JP7670053B2 - Sensor Array - Google Patents

Description

The present disclosure relates to signal detection circuits, drive detection circuits, sensor arrays and sensor systems.

In recent years, people have become more interested in their health, and developments in the field of healthcare are expected. Accordingly, arranging sensors in an array to obtain two-dimensional information on external stimuli such as pressure and temperature has become important in order to grasp a person's posture, movement, abnormalities, etc. For example, a pressure sensor array that combines a thin-film transistor array with a pressure-sensitive medium can be used to detect pressure distribution within a surface. Examples of pressure-sensitive media include those whose resistance changes with pressure (Patent Document 1) and those whose potential difference changes with pressure (Patent Document 2). Alternatively, a temperature sensor array that combines a thin-film transistor array with a temperature-sensitive medium can be used to detect temperature distribution within a surface.

A sensor array usually has detection points (here called "pixels") that correspond to the intersections of multiple scanning wirings and multiple signal wirings, and as the number of signal wirings increases, the circuit that detects signals from the sensor array also becomes larger in scale. The most easily conceivable signal detection circuit is one that has the same number of load resistors 122, voltage detection amplifiers 123, and AD converters 124 as the number of signal wirings 115, as shown in Figure 29, but this requires a large area and costs.

As a method for reducing the scale of the signal detection circuit, it has been proposed to reduce the number of downstream circuits by applying a switching circuit 100 as shown in FIG. 30. In this signal detection circuit, the output of multiple signal wirings 115 is input to one switching circuit 100 after passing through a voltage detection amplifier 123, and the output of one switching circuit 100 is input to one AD converter 124. For example, the circuit described in Patent Document 3 inputs the output from multiple electrodes to one multiplexer after passing through an operational amplifier, and the output of the one multiplexer is input to one A/D converter. Also, an example of a drive circuit including a signal detection circuit as shown in FIG. 30 is shown in FIG. 31. The drive detection circuit in FIG. 31 is the signal detection circuit in FIG. 30 with the addition of a control circuit 125 and a drive circuit 126, and detects the signal at the sensor point by applying an on-voltage to the scanning wiring 127. In Patent Document 4, a large number of signal wiring outputs are input to a small number of switching circuits after passing through a voltage detection amplifier, and then input to the same number of AD converters as the number of switching circuits. According to these, the number of voltage detection amplifiers and load resistors is not reduced, but the number of AD converters can be reduced.

JP 2014-119375 A Patent No. 2943437 Patent No. 4160251 Patent No. 3667058

However, while these circuits can reduce the number of AD converters downstream of the switching circuit, they still require the same number of voltage detection amplifiers and load resistors upstream of the switching circuit as there are signal wiring, which creates the problem that the overall size of the signal detection circuit cannot be significantly reduced.

The present disclosure has been made in consideration of the state of the art, and aims to provide a small-scale signal detection circuit. In addition, it aims to provide a drive detection circuit that is small in scale and has little error when the drive detection circuit includes a drive circuit and a control circuit in the signal detection circuit.

Another aspect of the present disclosure provides a display device including a plurality of signal wirings, a plurality of scanning wirings intersecting the signal wirings, a plurality of reference signal wirings parallel to the signal wirings, a plurality of pixel sections provided corresponding to each of the intersections of the signal wirings and the scanning wirings, the pixel sections including a pixel electrode, a first thin film transistor, a second thin film transistor, a fourth thin film transistor and a fifth thin film transistor, a drain wiring for supplying power to a drain electrode of the first thin film transistor, a sensor section connected to the pixel electrode, a common electrode connected to the sensor section, and a common wiring for supplying power to a gate electrode of the fourth thin film transistor , the pixel electrode being connected to a gate electrode of the first thin film transistor, a drain electrode of the first thin film transistor connected to a drain wiring, a source electrode of the first thin film transistor connected to a drain electrode of the second thin film transistor, a gate electrode of the second thin film transistor connected to a scanning wiring, a source electrode of the second thin film transistor connected to a signal wiring , a gate electrode of the fourth thin film transistor connected to a common wiring, a drain electrode of the fourth thin film transistor connected to a drain wiring, a source electrode of the fourth thin film transistor connected to a drain electrode of the fifth thin film transistor, a gate electrode of the fifth thin film transistor connected to the scanning wiring, and a source electrode of the fifth thin film transistor connected to a reference signal wiring .

According to the present disclosure, it is possible to provide a small-scale signal detection circuit. Furthermore, when the signal detection circuit includes a drive circuit and a control circuit, it is possible to provide a drive detection circuit that is small in scale and has little error.

FIG. 1 is a circuit diagram illustrating an example of a signal detection circuit according to a first embodiment of the present disclosure. FIG. 2 is a circuit diagram illustrating an example of a drive detection circuit including the signal detection circuit of FIG. FIG. 3 is a circuit diagram showing another example of a drive detection circuit including the signal detection circuit of FIG. FIG. 4 is an explanatory diagram showing a simple signal detection method. FIG. 5 is an explanatory diagram illustrating an example of the signal detection method of the present disclosure. FIG. 6 is a circuit diagram illustrating an example of a sensor array applied to the first embodiment. FIG. 7 is an explanatory diagram illustrating an example of a signal detection circuit according to the second embodiment of the present disclosure. FIG. 8 is an explanatory diagram illustrating an example of a drive detection circuit including the signal detection circuit of FIG. FIG. 9 is an explanatory diagram illustrating an example of the signal detection method of the present disclosure. FIG. 10 is a circuit diagram illustrating an example of a sensor array applied to the second embodiment. FIG. 11 is an explanatory diagram illustrating an example of a pixel circuit according to the third embodiment of the present disclosure. 12A and 12B are a plan view and a cross-sectional view showing a specific example of the pixel circuit of FIG. FIG. 13 is an explanatory diagram illustrating an example of a pixel circuit according to a fourth embodiment of the present disclosure. 14A and 14B are a plan view and a cross-sectional view showing a specific example of the pixel circuit of FIG. FIG. 15 is an explanatory diagram illustrating an example of a pixel circuit according to a fifth embodiment of the present disclosure. 16A and 16B are a plan view and a cross-sectional view showing a specific example of the pixel circuit of FIG. FIG. 17 is an explanatory diagram illustrating an example of a pixel circuit according to a sixth embodiment of the present disclosure. 18A and 18B are a plan view and a cross-sectional view showing a specific example of the pixel circuit of FIG. FIG. 19 is a block diagram illustrating an example of the care data collection and determination system of the present disclosure. FIG. 20 is an explanatory diagram showing an example of arrangement of the care sensor device of the present disclosure. FIG. 21 is a circuit diagram illustrating an example of a sensor array applied to the first embodiment. FIG. 22 is a circuit diagram illustrating an example of a current limiting circuit applied to the seventh embodiment. FIG. 23 is an explanatory diagram including an example of a detection circuit connected to the pixel circuit of FIG. FIG. 24 is an explanatory diagram including another example of a detection circuit connected to the pixel circuit of FIG. FIG. 25 is an explanatory diagram including an example of a detection circuit connected to the pixel circuit of FIG. FIG. 26 is an explanatory diagram including another example of a detection circuit connected to the pixel circuit of FIG. FIG. 27 is an explanatory diagram showing an example of a conventional pixel circuit. FIG. 28 is an explanatory diagram showing another example of a conventional pixel circuit. FIG. 29 is a circuit diagram illustrating an example of a conventional signal detection circuit. FIG. 30 is a circuit diagram showing another example of a conventional signal detection circuit. FIG. 31 is a circuit diagram illustrating an example of a conventional drive detection circuit.

The embodiments of the present disclosure will be described in detail below with reference to the drawings. Note that the drawings used below are not drawn to scale precisely in order to make the description easier to understand. Moreover, the embodiments of the present disclosure are a group of embodiments based on a unique single invention. Moreover, each aspect of the present disclosure is an aspect of a group of embodiments based on a single invention. Each configuration of the present disclosure may have each aspect of the present disclosure. Each feature of the present disclosure can be combined to form each configuration. Therefore, each feature of the present disclosure, each configuration of the present disclosure, each aspect of the present disclosure, and each embodiment of the present disclosure can be combined, and the combination can express a cooperative function and exhibit a synergistic effect.

[First embodiment]
FIG. 1 shows a circuit diagram illustrating an example of a signal detection circuit according to a first embodiment of the present disclosure. A sensor array to which this signal detection circuit is applied has M signal wirings 15. In FIG. 1, the M signal wirings 15 are divided into M ₂ blocks (parts surrounded by dashed lines in FIG. 1), each of which has M ₁ signal wiring. When the signal wirings 15 in each block are referred to as signal wirings A to M ₁ , the signal detection circuit of this embodiment has M 2 blocks in which the signal wirings A to M ₁ are connected to the inputs of a first switching circuit 101, and the output of the first switching circuit 101 is connected to a load resistor 20 and a voltage detection amplifier 53. Due to the presence of the first switching circuit 101, the number of required load resistors 20 and voltage detection amplifiers 53 is _{M 2 instead} of M, which can be reduced from the number of signal wirings 15.

Furthermore, the output of the voltage detection amplifier 53 of each block is connected to the input of the second switching circuit 102, and the output of the second switching circuit 102 is connected to the input of the AD converter 25. If the number of inputs of one second switching circuit 102 is L, the number of AD converters 25 required is (M ₂ /L) instead of M ₂ , which can be reduced from the number of voltage detection amplifiers 53. When the number of inputs L of the second switching circuit 102 is equal to M ₂ , the number of AD converters 25 required is one.

In this way, by combining the first switching circuit 101 and the second switching circuit 102, the number of load resistors 20 and voltage detection amplifiers 53 can be reduced below the number of signal wirings 15, and the number of AD converters 25 can be reduced below the number of voltage detection amplifiers 53, thereby reducing the scale of the signal detection circuit and reducing the installation area and manufacturing costs.

Although FIG. 1 shows the voltage detection amplifier 53 as a voltage follower, it is not limited to this and may be a circuit with an amplification factor other than 1 or an inverting amplifier circuit. The voltage detection amplifier 53 may also have a known oscillation prevention circuit, phase compensation circuit, capacitance correction circuit, and protection circuit. Furthermore, an FET (Field Effect Transistor) or the like may be substituted without using an operational amplifier. Also, FIG. 1 shows the load resistor 20 being placed between the signal line and GND, but if the voltage detection amplifier 53 is an inverting amplifier circuit, it may be placed between the signal line and the output of the voltage detection amplifier 53.

It is also preferable that the first switching circuit 101 is an analog multiplexer. Using an analog multiplexer allows high-speed switching without losing analog signal information. However, in cases where the signal voltage range is too large for an analog multiplexer to handle, a relay may be used.

By having the load resistor 20 on the output side of the first switching circuit 101, rather than on the input side, a current flows through the first switching circuit 101, lowering the impedance and making the circuit less susceptible to noise. In addition, a current flows only through the input signal line that has been switched to the output of the first switching circuit 101 among the signal wirings 15 connected to the first switching circuit 101, thereby reducing power consumption.

Next, a circuit diagram showing an example of a drive detection circuit including the signal detection circuit of FIG. 1 is shown in FIG. 2. The sensor array to which this drive detection circuit is applied has M signal wirings 15 and N scanning wirings 12. The drive detection circuit of FIG. 2 is obtained by adding a control circuit 5 and a drive circuit 6 to the signal detection circuit according to this embodiment, and the first switching circuit 101, the second switching circuit 102, the AD converter 25, and the drive circuit 6 are controlled by the control circuit 5. In order to control the first switching circuit 101, digital wiring 48 with a bit number n (where 2 ^n-1 <M ₁ ≦2 ⁿ ) that can switch the switching circuit with the number of inputs M ₁ is required. For example, the number of digital wirings 48 required in each block is 2 if M ₁ =4, 3 if M ₁ =8, and 4 if M ₁ =16.

When the number of digital outputs of the control circuit 5 is small, it is advisable to control the first switching circuit 101 using a counter 49 as shown in Figure 3. This allows the number of digital wirings 48 for switching the inputs of each block to be one each.

FIG. 4 shows an easily conceivable signal detection method when the drive detection circuit of FIG. 2 or FIG. 3 is applied. In FIG. 4, the second switching circuit 102 is switched to block 1 in advance. After applying an on-voltage to the first row of the scanning wiring 12, the first switching circuit 101 of block 1 is set to signal A, and the data of signal A is read by the AD converter 25. Next, the first switching circuit 101 is set to signal B, and the data of signal B is read by the AD converter 25. In the same manner, the data up to signal _M1 is sequentially read by the AD converter 25, and then the second switching circuit 102 is switched to block 2, and signals A to _M1 of block 2 are sequentially read in the same manner as block 1. Then, up to block M2 is read in the same manner as blocks 1 and _2. In this case, data can be read in the order of pixel arrangement, which is easy to understand, but there are the following problems.

Since the data is read by the AD converter 25 immediately after switching the first switching circuit 101, the signal is read before it stabilizes, resulting in a large error.

An improved signal detection method will be explained with reference to Figure 5. In Figure 5, all of the first switching circuits 101 are switched to signal A in advance. After applying an on-voltage to the first row of the scanning wiring 12, a certain period of time is waited.

Thereafter, the second switching circuit 102 is switched to block 1, the data of signal A in block 1 is read by the AD converter 25, and the first switching circuit 101 in block 1 is set to signal B. Next, the second switching circuit 102 is switched to block 2, the data of signal A in block 2 is read by the AD converter 25, and the first switching circuit 101 in block 2 is set to signal B. The same is done for blocks 3, 4, ..., and similarly for block _M2 , that is, the second switching circuit 102 is switched to block _M2 , the data of signal A in block _M2 is read by the AD converter 25, and the first switching circuit 101 in block _M2 is set to signal B. (The above is the "signal A reading and switching to signal B process.")

Thereafter, the second switching circuit 102 is switched to block 1, the data of signal B of block 1 is read by the AD converter 25, and the first switching circuit 101 of block 1 is set to signal C. Next, the second switching circuit 102 is switched to block 2, the data of signal B of block 2 is read by the AD converter 25, and the first switching circuit 101 of block 2 is set to signal C. The same is done for blocks 3, 4, ..., and similarly for block _M2 , that is, the second switching circuit 102 is switched to block _M2 , the data of signal B of block M2 is read by the AD converter 25, and the first switching circuit 101 of block _M2 is set to signal C. (The above is the "signal B reading and switching to signal C process.")

Thereafter, similarly to the "step of reading signal A and switching to signal B" and the "step of reading signal B and switching to signal C", the "step of reading signal C and switching to signal D", the "step of reading signal D and switching to signal E", ... are performed, followed by the "step of reading signal _M1 and switching to signal A", i.e., the second switching circuit 102 is switched to block 1, the data of signal _M1 in block 1 is read by the AD converter 25, and then the first switching circuit 101 in block 1 is set to signal A. Next, the second switching circuit 102 is switched to block 2, the data of signal _M1 in block 2 is read by the AD converter 25, and then the first switching circuit 101 in block 2 is set to signal A. The same process is carried out for blocks 3, 4, ..., and block _M2 , i.e., the second switching circuit 102 is switched to block _M2 , the data of signal _M1 in block _M2 is read by the AD converter 25, and then the first switching circuit 101 in block _M2 switches to signal A. However, this description is specifically described for ease of understanding, and does not limit signal _M1 to being after signal E, i.e., does not limit _M1 > 5, and _M1 may be any integer equal to or greater than 2. Moreover, block _M2 is not limited to being after block 4, i.e., does not limit _M2 > 4, and _M2 may be any integer equal to or greater than 2.

Next, an off voltage is applied to the first row of the scanning wiring 12, and then an on voltage is applied to the second row of the scanning wiring 12, and the process waits for a "certain time." As with the first row of the scanning wiring 12, the "process of reading signal A and switching to signal B" to the "process of reading signal _M1 and switching to signal A" are performed.

Similar operations are then performed up to the Nth row of scanning wiring 12, and an off voltage is applied to the Nth row of scanning wiring 12. At this stage, sensor information for one screen is obtained. By further repeating the same operations, data for multiple screens, i.e., time-dependent data of the signals of all pixels, can be obtained. (However, N is not limited to N>2, and N can be any integer equal to or greater than 1.)

5 is characterized in that, after switching the signal wiring selected by the first switching circuit 101 to a different signal wiring, the signal of the signal wiring selected by the first switching circuit of another block is measured one or more times before measuring the signal. This makes it possible to buy time until the signal stabilizes after switching the first switching circuit 101, and to improve the accuracy of the signal measurement. In particular, when the number of blocks is M ₂ , it is easy to perform another (M ₂ -1) measurements between the switching of the signal of the first switching circuit 101 and the measurement of the switched signal.

The features of the signal detection method of FIG. 5 are shown in more detail. The control circuit 5 performs a first process in which the drive circuit 6 applies an ON voltage to one scanning wiring selected from the multiple scanning wirings 12. After applying the ON voltage, the control circuit 5 waits for a certain period of time. Then, in one block selected by the second switching circuit, the signal of one signal wiring selected by the first switching circuit is read out via the AD converter 25, and after selecting another signal line different from the one signal wiring by the first switching circuit 101, before reading out the signal of the selected other signal wiring 15, the second switching circuit 102 repeats the steps of selecting another block different from the one block, reading out the signal, and switching the first switching circuit 101 of the other block, and the second switching circuit 102 selects one block, and a second process is performed in which the signals of one row of sensor units corresponding to the selected one scanning wiring 12 are read out in sequence through these processes. Furthermore, a third process is performed in which the drive circuit 6 applies an off voltage to one selected scanning line 12 after the second process is completed. The first process, standby, second process, and third process are repeated for all scanning lines 12, thereby reading out signals from all sensor units.

However, the procedure of selecting another signal line different from one signal wiring 15 by the first switching circuit 101 in one block and the procedure of selecting another block different from one block by the second switching circuit 102 may be reversed. That is, the second process may include a procedure of reading out the signal of one signal wiring 15 selected by the first switching circuit 101 in one block selected by the second switching circuit 102 via the AD converter 25, selecting another block different from one block by the second switching circuit 102, selecting another signal line different from one signal wiring 15 by the first switching circuit 101 of one block, and then reading out the signal of the other block before reading out the signal of the other signal wiring 15 of the one block, a procedure of switching the second switching circuit 102, and a procedure of switching the first switching circuit 101 of the other block, and the signals of one row of sensor units corresponding to the selected one scanning wiring 12 may be read out in sequence by these processes.

Therefore, the second process includes repeating at least a step of reading out a signal from the other block, a step of switching the second switching circuit 102, and a step of switching the first switching circuit 101 of the other block, after selecting another signal wiring 15 different from the one signal wiring 15 by the first switching circuit 101 of the one block, before reading out a signal from the other signal wiring 15 of the one block.

Furthermore, it is desirable that the "certain time" which is waited for a certain period of time after application of an on-voltage to one of the N scanning wirings 12 is at least (M ₂ -1) times the measurement time of the AD converter 25. In this way, for signal A of block 1, which is the first measurement of one screen, it is possible to have at least the measurement time of the AD converter 25 x (M ₂ -1) before measuring signal A after first switching circuit 101 is switched to signal A, which makes it possible to buy time until the signal stabilizes, just like the measurement of other signals, and it is possible to increase the accuracy of the signal measurement to the same level as other signals.

An example of a sensor array suitable for the signal detection circuit, drive detection circuit, and signal detection method of this embodiment will be described. FIG. 6 is a circuit diagram showing an example of a sensor array applied to the first embodiment. In the sensor array, a pixel circuit is formed by a first thin film transistor T1 and a second thin film transistor T2 at the intersection of a matrix of N scanning wirings 12 and M signal wirings 15, and a pressure-sensitive medium 9 is provided as a sensor unit 109 between the gate electrode of the first thin film transistor T1 and the common electrode 10. A drain wiring 14 is connected to the drain of the first thin film transistor T1, a source of the first thin film transistor T1 is connected to the drain of the second thin film transistor T2, a gate of the second thin film transistor T2 is connected to the scanning wiring 12, and a source of the second thin film transistor T2 is connected to the signal wiring 15. A voltage dependent on pressure is generated in the pressure-sensitive medium 9. When one of the scanning wirings 12 is turned on, a current dependent on the stimulus (pressure, etc.) of the pixel of that row flows through the signal wiring 15. The sensor unit 109 is preferably a pressure-sensitive medium 9, for example, polyvinylidene difluoride (PVDF) or poly(vinylidene difluoride-trifluoroethylene copolymer). Note that FIG. 6 is an example, and the sensor array is not limited to this structure. FIG. 21 is a circuit diagram showing an example of a sensor array applied to the first embodiment. In the sensor array, a pixel circuit is formed by a thin film transistor 38 at the intersection of a matrix of N scanning wirings 12 and M signal wirings 15, and a pressure-sensitive medium 39 is provided between the drain electrode of the thin film transistor 38 and the power supply wiring 36. The gate of the thin film transistor 38 is connected to the scanning wiring 12, and the source of the thin film transistor 38 is connected to the signal wiring 15. The resistance value of the pressure-sensitive medium 39 changes depending on the pressure. When one of the scanning wirings 12 is turned on, a current that depends on the pressure of the pixel of that row flows through the signal wiring 15. The pressure-sensitive medium 39 is preferably rubber or the like in which conductive particles are dispersed. Alternatively, another type of sensor unit 109 may be adopted and used as another type of pressure sensor, displacement sensor, temperature sensor, etc. The power supply wiring 36 may have a current limiting circuit 40, which will be described later in the seventh embodiment.

As described above, in the signal detection circuit according to the first embodiment, the number of load resistors 20 and voltage detection amplifiers 53 can be reduced by providing the first switching circuit 101 upstream of the load resistors 20 and voltage detection amplifiers 53, and the number of AD converters 25 can be reduced by providing the second switching circuit 102 downstream of the voltage detection amplifiers 53, thereby reducing the scale of the signal detection circuit. In addition, by applying the signal detection circuit, the scale of the drive detection circuit can also be reduced. In addition, after the signal is switched by the first switching circuit 101, the measurement of the switched and unmeasured signals of other blocks can be performed before measuring the signal, so that the measurement can be performed after the switching signal has stabilized.

Second Embodiment
The second embodiment of the present disclosure will be described with reference to FIG. 7. FIG. 7 is an explanatory diagram showing an example of a signal detection circuit according to the second embodiment of the present disclosure. A sensor array to which this signal detection circuit is applied has M ₁ signal wiring 15 and M ₁ reference signal wiring 16. The signal wiring 15 and the reference signal wiring 16 are divided into M ₂ blocks, each of which has M ₁ signal wiring 15 and reference signal wiring 16. The signal wirings A to M ₁ of each block are connected to the input of the first switching circuit 101, and the output of the first switching circuit 101 is connected to the load resistor 20 and the voltage detection amplifier 53. In addition, the reference signal wirings A to M ₁ of each block are connected to the input of the third switching circuit 103, and the output of the third switching circuit 103 is connected to the load resistor 21 and the voltage detection amplifier 54. Therefore, the number of required load resistors 20 and voltage detection amplifiers 53 is not the sum of the signal wirings 15 and the reference signal wirings 16 (M ₁ ×2), but twice the number of blocks (M ₂ ×2).

Furthermore, the output of the voltage detection amplifier 53 of the signal and the output of the voltage detection amplifier 54 of the reference signal corresponding to the signal are input to the differential amplifier circuit 24. The number of required differential amplifier circuits 24 is _M2 , which is the same as the number of blocks. The output of the differential amplifier circuit 24 is connected to the input of the second switching circuit 102, and the output of the second switching circuit 102 is connected to the input of the AD converter 25. If the number of inputs of the second switching circuit 102 is L, the number of required AD converters 25 is ( _M2 /L) instead of _M2 , which can be reduced from the number of differential amplifier circuits 24. If the number of inputs L of the second switching circuit 102 is equal to _M2 , the number of required AD converters 25 is one.

In this way, by combining the first switching circuit 101, the third switching circuit 103, and the second switching circuit 102, the number of load resistors 20 and voltage detection amplifiers 53 can be reduced below the number of signal wirings 15, the number of load resistors 21 and voltage detection amplifiers 54 can be reduced below the number of reference signal wirings 16, and the number of AD converters 25 can be reduced below the number of differential amplifier circuits 24, thereby reducing the scale of the signal detection circuit and reducing the installation area and costs.

In FIG. 7, the voltage detection amplifiers 53 and 54 are shown as voltage followers, but are not limited to this and may be circuits with an amplification factor other than 1 or inverting amplifier circuits. The voltage detection amplifiers 53 and 54 may also have known oscillation prevention circuits, phase compensation circuits, capacitance correction circuits, and protection circuits. Furthermore, an FET or the like may be used instead of an operational amplifier. In FIG. 7, the load resistors 20 and 21 are shown to be installed between the signal line and GND, but if the voltage detection amplifiers 53 and 54 are inverting amplifier circuits, they may be installed between the signal line and the output of the inverting amplifier. Furthermore, the differential amplifier circuit 24 may be a circuit with an amplification factor of 1 that sees the difference between the signal and the reference signal, but the amplification factor may be other than 1. The differential amplifier circuit 24 can shift the output voltage by the base voltage Vbase. In the differential amplifier circuit 24, by adding Vbase to the signal wiring output-reference output, it can be reliably detected even when the signal wiring output-reference output is small or negative.

It is also preferable that the first switching circuit 101 and the third switching circuit 103 are analog multiplexers. Analog multiplexers allow high-speed switching without losing analog signal information. However, in cases where the signal voltage range is too large for an analog multiplexer to handle, relays may be used.

Since the load resistors 20 and 21 are on the output side, not the input side, of the first switching circuit 101 and the third switching circuit 103, a current flows through the first switching circuit 101 and the third switching circuit 103, lowering the impedance and making the circuit less susceptible to noise. Also, a current flows only through the input signal line switched to the output of the first switching circuit 101 among the signal wirings 15 connected to the first switching circuit 101, and only through the input reference signal line switched to the output of the third switching circuit 103 among the reference signal wirings 16 connected to the third switching circuit 103, so that power consumption can be reduced.

Next, the drive detection circuit according to this embodiment will be described. FIG. 8 is an explanatory diagram showing an example of a drive detection circuit including the signal detection circuit of FIG. 5. The sensor array to which this drive detection circuit is applied has M signal wirings 15, M reference signal wirings 16, and N scanning wirings 12. The drive detection circuit of FIG. 8 is a signal detection circuit according to this embodiment, to which a control circuit 5 and a drive circuit 6 are added, and the first switching circuit 101, the third switching circuit 103, the second switching circuit 102, the AD converter 25, and the drive circuit 6 are controlled by the control circuit 5. When the number of digital outputs of the control circuit 5 is small, the first switching circuit 101 and the third switching circuit 103 are controlled using a counter 49. By using the counter 49, the digital wiring 48 for switching the input of each block can be reduced to one each.

When applying the drive detection circuit shown in Figure 8, as in the first embodiment, the signal detection method shown in Figure 9 is preferable rather than a simple signal detection method.

In Figure 9, all first switching circuits 101 are switched to signal A, the third switching circuit 103 is switched to reference signal A, and the second switching circuit 102 is switched to block 1. After applying an on-voltage to the first row of the scanning wiring 12, a "certain period of time" is waited.

Then, data corresponding to the difference between the signal A and the reference signal A of the block 1 is read by the AD converter 25, and the first switching circuit 101 of the block 1 is set to the signal B, and the third switching circuit 103 of the block 1 is set to the reference signal B. Next, the second switching circuit 102 is switched to the block 2, and data corresponding to the difference between the signal A and the reference signal A of the block 2 is read by the AD converter 25, and the first switching circuit 101 of the block 2 is set to the signal B, and the third switching circuit 103 of the block 2 is set to the reference signal B. The same is carried out for the blocks 3, 4, ..., and similarly for the block _M2 , that is, the second switching circuit 102 is switched to the block _M2 , and data corresponding to the difference between the signal A and the reference signal A of the block _M2 is read by the AD converter 25, and the first switching circuit 101 of the block _M2 is set to the signal B, and the third switching circuit 103 of the block _M2 is set to the reference signal B. (The above is the "signal difference A reading and switching to signal B process")

Thereafter, the second switching circuit 102 is switched to block 1, data corresponding to the difference between the signal B of block 1 and the reference signal B is read by the AD converter 25, and then the first switching circuit 101 of block 1 is set to signal C and the third switching circuit 103 of block 1 is set to reference signal C. Next, the second switching circuit 102 is switched to block 2, data corresponding to the difference between the signal B of block 2 and the reference signal B is read by the AD converter 25, and then the first switching circuit 101 of block 2 is set to signal C and the third switching circuit 103 of block 2 is set to reference signal C. The same is carried out for blocks 3, 4, ..., and similarly for block _M2 , that is, the second switching circuit 102 is switched to block _M2 , data corresponding to the difference between the signal B of block _M2 and the reference signal B is read by the AD converter 25, and then the first switching circuit 101 of block _M2 is set to signal C and the third switching circuit 103 of block _M2 is set to reference signal C. (The above is the "process of reading signal difference B and switching to signal C")

Then, "signal difference A is read and a process of switching to signal B" and "signal difference B is read and a process of switching to signal C"
Similarly, the "step of reading signal difference C and switching to signal D", "step of reading signal difference D and switching to signal E", ... are followed by the "step of reading signal difference M1 and switching to signal A", that is, the second switching circuit 102 is switched to block 1, data corresponding to the difference between the signal _M1 of block ₁ and the reference signal M1 is read by the AD converter 25, and then the first switching circuit 101 of block 1 is set to signal A and the third switching circuit 103 of block 1 is set to reference signal A. Next, the second switching circuit 102 is switched to block 2, data corresponding to the difference between the signal _M1 of block 2 and the reference signal _M1 is read by the AD converter 25, and then the first switching circuit 101 of block 2 is set to signal A and the third switching circuit 103 of block 2 is set to reference signal A. The same process is carried out for blocks 3, 4, ..., and block _M2 , i.e., the second switching circuit 102 is switched to block _M2 , data corresponding to the difference between the signal _M1 of block _M2 and the reference signal _M1 is read by the AD converter 25, and then the first switching circuit 101 of block _M2 is set to signal A, and the third switching circuit 103 of block _M2 is set to reference signal A. However, this description is specifically described for ease of understanding, and does not limit signal _M1 to being after signal E, i.e., does not limit _M1 > 5, and _M1 may be any integer equal to or greater than 2. Moreover, block _M2 is not limited to being after block 4, i.e., does not limit _M2 > 4, and _M2 may be any integer equal to or greater than 2.

Next, an off voltage is applied to the first row of scanning wiring 12, and then an on voltage is applied to the second row of scanning wiring 12, and the process waits for a "certain time." As with the first row of scanning wiring 12, the "step of reading signal difference A and switching to signal B" to the "step of reading signal difference _M1 and switching to signal A" are performed.

Similar operations are then performed up to the Nth row of scanning wiring 12, and an off voltage is applied to the Nth row of scanning wiring 12. At this stage, sensor information for one screen is obtained. By further repeating the same operations, data for multiple screens, i.e., time-dependent data of the signal differences for all pixels, can be obtained. (However, N is not limited to being greater than 2, and N can be any integer equal to or greater than 1.)

The feature of the signal detection method of Fig. 9 is that after switching to the signal wiring selected by the first switching circuit 101 and the reference signal corresponding to that signal wiring, the difference between the signal of the signal wiring selected by the first switching circuit 101 of another block and the signal of the reference signal wiring corresponding to that signal wiring is measured one or more times before measuring the signal difference between them. This makes it possible to buy time until the signal becomes stable after switching the first switching circuit 101 and the third switching circuit 103, and to improve the accuracy of the signal measurement. In particular, when the number of blocks is M ₂ , it is easy to insert (M ₂ -1) measurements.

The features of the signal detection method in Fig. 9 will now be described in more detail. The control circuit 5 performs a first process in which the drive circuit 6 applies an on-voltage to one scanning wiring 12 selected from the multiple scanning wirings 12. After applying the on-voltage, the process waits for a certain period of time. Then, in one block selected by the second switching circuit 102, a signal difference between one signal wiring 15 selected by the first switching circuit 101 and a reference signal wiring 16 corresponding to one signal wiring 15 selected by the third switching circuit 103 is read out via the AD converter 25, and after selecting another signal line and reference signal wiring 16 different from the one signal wiring 15 and the reference signal wiring 16 by the first and third switching circuits, before reading out the signal difference between the selected other signal wiring 15 and the reference signal wiring 16, the procedure of selecting another block different from the one block by the second switching circuit 102, the procedure of reading out the signal difference, and the procedure of switching the first and third switching circuits of the other block are repeated, and a procedure of selecting one block by the second switching circuit 102 is performed, and the signal difference of one row of sensor units corresponding to the selected one scanning wiring 12 is sequentially read out by these processes. Furthermore, a third process is performed in which the driving circuit 6 applies an off voltage to the selected one scanning wiring 12 after the second process is completed. The first process, waiting, second process, and third process are repeated for all the scanning lines 12, thereby reading out signals from all the sensor units.

However, the procedure of selecting another signal wiring 15 and reference signal wiring 16 different from one signal wiring 15 and reference signal wiring 16 in one block by the first and third switching circuits and the procedure of selecting another block different from the one block by the second switching circuit 102 may be reversed. That is, the second process may include repeating a procedure of reading out the signal difference between one signal wiring 15 and reference signal wiring 16 selected by the first and third switching circuits in one block selected by the second switching circuit 102 via the AD converter 25, selecting another block different from the one block by the second switching circuit 102, selecting another signal wiring 15 and reference signal wiring 16 different from the one signal wiring 15 and reference signal wiring 16 using the first and third switching circuits of the one block, and then reading out the signal difference between the other signal wiring 15 and reference signal wiring 16 of the one block, a procedure of switching the second switching circuit 102, and a procedure of switching the first and third switching circuits of the other block, and sequentially reading out signals of one row of sensor units corresponding to the selected one scanning wiring 12 through these processes.

Therefore, the second process involves selecting another signal wiring 15 and reference wiring 16 different from one signal wiring 15 and reference signal wiring 16 by the first switching circuit 101 and third switching circuit 103 of one block, and then repeating at least a procedure of reading out the signal difference of the other block, a procedure of switching the second switching circuit 102, and a procedure of switching the first switching circuit 101 and third switching circuit 103 of the other block before reading out the signal difference of the other signal wiring 15 and reference signal wiring 16 of the one block.

Moreover, it is desirable that the "certain time" which is waited for a certain time after applying an on-voltage to one of the N scanning wirings 12 is at least (M ₂ -1) times the measurement time of the AD converter 25. In this way, for the difference between the signal A and the reference signal A of block 1, which is the first measurement of one screen, after the first switching circuit 101 and the third switching circuit 103 are switched to the signal A, at least the measurement time x (M ₂ -1) of the AD converter 25 can be inserted before measuring the difference between the signal A and the reference signal A, and as with the measurement of other signal differences, it is possible to buy time until the signal and the reference signal become stable, and the accuracy of the signal measurement can be increased to the same level as other signal differences. Moreover, since the measurement is performed after the signal and the reference signal become stable, the time constant until the signal becomes stable and the time constant until the reference signal becomes stable do not necessarily have to be the same.

A suitable sensor array applicable to the signal detection circuit, drive detection circuit, and signal detection method of this embodiment will be described. FIG. 10 is a circuit diagram showing an example of a sensor array applied to the second embodiment. In the sensor array, a pixel circuit is formed by a first thin film transistor T1 and a second thin film transistor T2 at the intersection of a matrix of N scanning wirings 12 and M signal wirings 15, and a pressure-sensitive medium 9 is provided as a sensor unit 109 between the gate electrode of the first thin film transistor T1 and the common electrode 10. In addition, a reference circuit is formed by a third thin film transistor T3 and a fourth thin film transistor T4 at the intersection of N scanning wirings 12 and M reference signal wirings 16, and the third thin film transistor T3 is adjacent to the first thin film transistor T1. It is desirable that the channel length/channel width of the third thin film transistor T3 is equal to the channel length/channel width of the first thin film transistor T1, and the channel length/channel width of the fourth thin film transistor T4 is equal to the channel length/channel width of the second thin film transistor T2. The drain of the first thin film transistor T1 is connected to the drain wiring 14, the source of the first thin film transistor T1 is connected to the drain of the second thin film transistor T2, the gate of the second thin film transistor T2 is connected to the scanning wiring 12, and the source of the second thin film transistor T2 is connected to the signal wiring 15. A voltage dependent on a stimulus (pressure, etc.) is generated in the sensor unit 109. On the other hand, the gate of the third thin film transistor T3 is connected to the common electrode 10, the drain of the third thin film transistor T3 is connected to the drain wiring 14, the source of the third thin film transistor T3 is connected to the drain of the fourth thin film transistor T4, the gate of the fourth thin film transistor T4 is connected to the scanning wiring 12, and the source of the fourth thin film transistor T4 is connected to the reference signal wiring 16. When one of the scanning wirings 12 is turned on, a current dependent on the pressure of the pixel of that row flows to the signal wiring 15, and a current having characteristics close to those of the pixel circuit of that row and not dependent on a stimulus (pressure, etc.) flows to the reference signal wiring 16. As the sensor section 109, a pressure-sensitive medium 9, for example, polyvinylidene difluoride (PVDF) or poly(vinylidene difluoride-trifluoroethylene copolymer) is suitable. The sensor array applicable to this embodiment is not limited to the sensor array having the structure shown in FIG. 10. For example, a pressure-sensitive medium whose resistance changes depending on pressure may be used, and a signal from an element to which pressure is applied and a reference signal from an element to which no pressure is applied may be used. Alternatively, another sensor section 109 may be adopted and used for other types of pressure sensors, displacement sensors, temperature sensors, etc. The drain wiring 14 may have a current limiting circuit 40, which will be described later in the seventh embodiment.

By subtracting the detection voltage in the adjacent reference signal wiring 16 from the detection voltage from the signal wiring 15, the in-plane distribution of the thin film transistor array can be canceled because the characteristics of adjacent thin film transistors are similar. In addition, because the temperatures of adjacent thin film transistors are equivalent, the temperature dependence of the thin film transistors can be largely canceled.

As described above, in the signal detection circuit according to the second embodiment, the first switching circuit 101 is provided upstream of the load resistor 20 and the voltage detection amplifier 53, and the third switching circuit 103 is provided upstream of the load resistor 21 and the voltage detection amplifier 54, thereby reducing the number of load resistors 20, 21 and voltage detection amplifiers 53, 54. Furthermore, the second switching circuit 102 is provided downstream of the differential amplifier circuit 24, thereby reducing the number of AD converters 25 and reducing the scale of the signal detection circuit. In addition, by applying the signal detection circuit, the scale of the drive detection circuit can also be reduced. In addition, after switching the signal with the first switching circuit 101 and the third switching circuit 103, the signal difference between the other blocks that have been switched and not yet measured is measured before measuring the signal difference, so that the measurement can be performed after the switching signal has stabilized, thereby providing a signal detection method with small errors.

In conventional sensor arrays, the pressure-sensitive medium with variable resistance is prone to degradation. Therefore, the use of a type of pressure-sensitive medium with variable potential difference as in Patent Document 2 has been considered (Figure 28). However, the circuit that has a load resistor in the pixel and reads out the potential as in Patent Document 2 has the problem of being vulnerable to noise. In addition, because the first thin-film transistor 41 is used as a source-grounded circuit, there is a problem that it is susceptible to the effects of variations in the mobility and threshold value of the thin-film transistor. Furthermore, the pressure-sensitive medium in Patent Document 2 is inorganic, and is vulnerable to mechanical shock.

Therefore, the third to sixth embodiments describe a sensor array that is less affected by variations in the mobility and threshold voltage of thin-film transistors and is resistant to noise.

[Third embodiment]
An example of a conventional pixel circuit is shown in FIG. 27. In FIG. 27, the pressure-sensitive medium 130, which is a sensor section, is a type whose resistance changes depending on pressure, and one end is connected to a common electrode and the other end is connected to the drain electrode of a thin film transistor 31. A power source is connected to the common electrode. A gate voltage (on voltage) that turns on the thin film transistor 31 is applied to one of the scanning wirings 32, and a gate voltage (off voltage) that turns off the thin film transistor 31 is applied to the other scanning wirings 32. A current flowing through the pressure-sensitive medium 130 of the corresponding pixel flows to the signal wiring 33 through the thin film transistor 31 belonging to the scanning wiring 32 to which the on voltage is applied. Pressure data for all rows is read out by sequentially changing the scanning wirings 32 to be turned on one by one.

Another example of a conventional pixel circuit is shown in FIG. 28. In FIG. 28, the pressure-sensitive medium 140, which is the sensor section, is a type in which the potential difference changes depending on the pressure. One end of the pressure-sensitive medium 140 is connected to the gate electrode of the first thin film transistor 41, and the other end is connected to the source electrode of the first thin film transistor 41. The first thin film transistor 41 is connected to a power source via a drain resistor 43 in the pixel, and the first thin film transistor 41 is a source ground circuit. A gate voltage (on voltage) that turns on the second thin film transistor 42 is applied to one of the scanning wirings 44, and a gate voltage (off voltage) that turns off the second thin film transistor 42 is applied to the other scanning wirings 44. Then, the drain voltage of the corresponding pixel is drawn to the signal wiring 45 through the second thin film transistor 42 belonging to the scanning wiring 44 to which the on voltage is applied. By sequentially changing the scanning wirings 44 to be turned on one by one, the pressure data of all rows can be read out.

However, because the circuit that reads out the voltage has a high input impedance, if the signal wiring 45 is long, noise is likely to be mixed into the signal. Furthermore, if the impedance of the detection circuit in this circuit were lowered to make it less susceptible to noise, a current (not necessarily dependent on pressure) would flow through the detection circuit in addition to the current (dependent on pressure) flowing through the first thin-film transistor 41, and the voltage drop across the drain resistor 43 due to the current flowing through the detection circuit would become an error. Furthermore, the source-grounded circuit amplifies both the voltage and current, so it has high sensitivity, but the signal voltage is easily affected by variations in the mobility and threshold value of the first thin-film transistor 41.

Therefore, a pixel circuit according to a third embodiment of the present disclosure is shown in FIG. 11. In FIG. 11, the sensor unit 109 (for example, pressure-sensitive medium 9) is a type in which the potential difference changes depending on a stimulus (pressure, etc.). One end of the sensor unit 109 is connected to the common electrode 10, and the other end is connected to the gate electrode G1 of the first thin film transistor, the drain electrode D1 of the first thin film transistor is connected to the power supply Vdd via the drain wiring 14, the source electrode S1 of the first thin film transistor is connected to the drain electrode D2 of the second thin film transistor, the gate electrode G2 of the second thin film transistor is connected to the scanning wiring 12, the source electrode S2 of the second thin film transistor is connected to the signal wiring 15, and when the load resistor 20 in the signal detection circuit is included, the first thin film transistor is a drain ground circuit (source follower). A gate voltage (on voltage) that turns on the second thin film transistor is applied to one of the scanning wirings 12, and a gate voltage (off voltage) that turns off the second thin film transistor is applied to the other scanning wiring 12. Then, through the second thin film transistor belonging to the scanning wiring 12 to which the on voltage is applied, the source electrode S1 of the corresponding pixel is connected to the signal wiring 15, and then to the load resistor 20 in the signal detection circuit. That is, since the load resistor 20 is outside the array, a current flows through the signal wiring 15, so the impedance is low and noise is unlikely to be mixed into the signal. In addition, since it is a drain-grounded (source follower) circuit, only the current is amplified and the source potential is close to the gate potential, so the signal voltage is unlikely to be affected by the variation in the mobility of the first thin film transistor. By sequentially changing the scanning wiring 12 to be turned on one by one, the pressure data of each row can be read out.

In addition, the potential of the common electrode 10 is added to a potential difference that depends on the stimulus (pressure, etc.) of the sensor unit 109 and applied to the gate electrode G1 of the first thin film transistor, so that the operating point can be adjusted by the potential of the common electrode 10.

The detection method of the sensor array in the third embodiment can suitably use, for example, the signal detection circuit, drive detection circuit, and signal detection method in the first embodiment. In this case, the number of scanning wirings 12 of the sensor array is N, and the number of signal wirings 15 is M.

A pressure-sensitive medium 9 (a type in which the potential difference changes) is suitable as the sensor unit 109. However, it is also possible to use other pressure-sensitive media, displacement-sensitive media, temperature-sensitive media, etc. as the sensor unit 109.

In addition, when the potential of the drain wiring 14 is changed from 0 to Vdd immediately before the measurement, the potential of the pixel electrode 8 shifts by ΔVp = Vdd × Cgd1 / (Cgd1 + Cp), assuming that the capacitance between the gate and drain electrodes of the first thin film transistor (including the pixel electrode 8 connected to the gate electrode G1 and the drain wiring 14 connected to the drain electrode D1) is Cgd1 and the capacitance between the pixel electrode 8 and the common electrode 10 is Cp. This shift needs to be sufficiently small compared to the maximum potential change of the sensor unit 109, and needs to be suppressed to within 10% of the maximum potential change, for example. To suppress the above shift to within 10% of the maximum potential change, | Vdd × Cgd1 / (Cgd1 + Cp) | ≦ maximum potential change × 0.1. Here, the maximum potential change is the amount of change in the pixel electrode potential when a stimulus of the maximum value of the detection range set for the sensor is applied from a state in which no stimulus (pressure, etc.) is applied to the sensor. For example, when the maximum potential change amount is 4 [V], |Vdd×Cgd1/(Cgd1+Cp)|≦0.4 is satisfied.

A specific example of the sensor array shown in FIG. 11 is shown in FIG. 12. On an insulating substrate 1, gate electrodes G1 and G2 (G2 is connected to the scanning wiring 12), a gate insulating film 3 is provided thereon, semiconductors SC1 and SC2 are provided thereon, source electrodes S1 and S2 and drain electrodes D1 and D2 are provided thereon (S1 is connected to D2 via a connection wiring 17, D1 is connected to a drain wiring 14, and S2 is connected to a signal wiring 15), an interlayer insulating film 7 is provided thereon, and a pixel electrode 8 is provided thereon (the pixel electrode 8 is connected to the gate electrode G1 via via wirings 18U and 18L provided in the opening of the interlayer insulating film 7 and the opening of the gate insulating film 3). It further has a sensor portion 109 and a common electrode 10. The sensor portion 109 is in contact with or bonded to the pixel electrode 8.

An insulating etching stopper layer may be formed on the semiconductors SC1 and SC2, and contact layers having a lower resistance than the semiconductor 4 may be formed at the interfaces between the semiconductors SC1 and SC2 and the source electrodes S1 and S2 and at the interfaces between the semiconductors SC1 and SC2 and the drain electrodes D1 and D2.

Also, if the pixel electrode 8 is thick, there may be a gap in the area where the pixel electrode 8 is not present, or the gap may be filled with an insulating material.

In FIG. 12, the pixel electrode 8 also serves as the back gate electrode of the first thin film transistor. This provides a more stable operation than when the pixel electrode 8 is simply connected to the gate electrode G1 without covering the channel portion of the first thin film transistor. Also, although not shown in FIG. 12, a back gate electrode may be provided in the second thin film transistor and a common electrode potential, GND potential, or a specific constant potential may be connected thereto. This provides a stable operation of the second thin film transistor.

The insulating substrate 1 may be glass, but is preferably an organic material (e.g., PET (polyethylene terephthalate), PEN (polyethylene naphthalate), PES (polyethersulfone), PI (polyimide), PC (polycarbonate), etc.). The gate electrodes G1 and G2 are preferably a metal (e.g., Al, Ti, Mo, Ta, etc., or an alloy mainly composed of these). The gate insulating film 3 is preferably an organic material (acrylic, epoxy, etc.), an inorganic material (SiO ₂ , SiN, etc.), or a laminate or mixture thereof. The semiconductors SC1 and SC2 are preferably an organic semiconductor, an oxide semiconductor, or amorphous Si. The source electrodes S1 and S2 and the drain electrodes D1 and D2 are preferably a metal (e.g., Al, Ti, Mo, Ta, etc., or an alloy mainly composed of these). The interlayer insulating film 7 is preferably an organic material (acrylic, epoxy, etc.), an inorganic material (SiO ₂ , SiN, etc.), or a laminate or mixture thereof. The pixel electrodes 8 are preferably made of a metal (e.g., Al, Ti, Mo, Ta, etc., or an alloy mainly made of these) or a mixture of metal particles and resin (e.g., Ag paste). The sensor section 109 is preferably made of a pressure-sensitive medium 9, particularly an organic piezoelectric material (polyvinylidene fluoride, polyvinylidene fluoride-trifluoroethylene copolymer, polylactic acid, porous electret type, etc.), but may also be a displacement-sensitive medium or a temperature-sensitive medium. The common electrode 10 is preferably made of a metal (e.g., Al, Ti, Mo, Ta, etc., or an alloy mainly made of these).

However, flexibility is often desired for the sensor array, and in order to ensure flexibility, it is particularly desirable for the insulating substrate 1, gate insulating film 3, interlayer insulating film 7, and sensor portion 109 (pressure-sensitive medium 9, etc.) to be primarily composed of organic materials.

In addition, if the pixel electrode 8 is made of metal, it is easy to make the pixel electrode 8 thinner, and the gap between the interlayer insulating film 7 in the portion other than the pixel electrode 8 and the sensor portion 109 (pressure-sensitive medium 9, etc.) can be eliminated, improving the uniformity of the measurement. If the pixel electrode 8 is a mixture of metal particles and resin, it is easy to make the pixel electrode 8 thicker, and the gap between the interlayer insulating film 7 in the portion other than the pixel electrode 8 and the sensor portion 109 (pressure-sensitive medium 9, etc.) can be increased, allowing a specified pressure to be obtained with less force, i.e., the sensitivity can be increased.

Figure 12 shows a bottom gate/top contact case, but the present disclosure is not limited to this and may also be top gate or bottom contact.

[Fourth embodiment]
A pixel circuit according to a fourth embodiment of the present disclosure is shown in Fig. 13. In Fig. 13, a third thin film transistor is further included in the pixel circuit of Fig. 11, and the drain electrode D3 of the third thin film transistor is connected to the pixel electrode 8, the source electrode S3 is connected to the common wiring 11, and the gate electrode G3 is connected to the reset wiring 13.

Before measurement, with no stimulus (pressure, etc.) applied to the sensor unit 109, a voltage (on voltage) that turns on the third thin film transistor is applied to the reset wiring 13. Then, the pixel electrode 8 is connected to the common wiring 11 via the third thin film transistor, and the charge accumulated in the pixel electrode 8 can be set to zero. Here, the common wiring 11 is at the same potential as the common electrode 10. Then, a voltage (off voltage) that turns off the third thin film transistor is applied to the reset wiring 13, and a voltage Vdd is applied to the drain wiring 14.

In the case of a sensor unit 109 of a type in which the potential difference changes with pressure, such as a piezoelectric element, the potential difference is zero when the stimulus (pressure, etc.) is zero in a steady state. However, depending on the past history, for example if the stimulus (pressure, etc.) continues to be applied until just before use, an error occurs due to the residual charge in the sensor unit 109, such that the potential difference is not zero even when the stimulus (pressure, etc.) is zero. In the sensor array of this embodiment, the third thin film transistor can be turned on to reset the charge of the pixel electrode 8 just before measurement, thereby eliminating errors due to the residual charge in the sensor unit 109.

The capacitance between the gate and drain electrodes of the first thin film transistor (including the pixel electrode 8 connected to the gate electrode G1 and the drain wiring 14 connected to the drain electrode D1) is Cgd1, the capacitance between the gate and drain electrodes of the third thin film transistor (including the capacitance of the reset wiring 13 connected to the gate electrode G3 and the pixel electrode 8 connected to the drain electrode D3) is Cgd3, and the capacitance between the pixel electrode 8 and the common electrode 10 is Cp. Other parasitic capacitances are ignored because they are small. When an off voltage is applied to the reset wiring 13 to turn off the third thin film transistor, the potential of the pixel electrode 8 shifts by ΔVp=-{Vreset(on)-Vreset(off)}×Cgd3/(Cgd3+Cp+Cgd1). In addition, when the potential of the drain wiring 14 is changed from 0 to Vdd, the potential of the pixel electrode 8 shifts by ΔVp=Vdd×Cgd1/(Cgd1+Cp+Cgd3). In the case of an n-channel TFT, the former is negative and the latter is positive, and in the case of a p-channel TFT, the former is positive and the latter is negative, and in either case, the voltage changes cancel each other out. This voltage change must be sufficiently smaller than the maximum potential change of the pressure-sensitive medium 9, and must be suppressed to within 10% of the maximum potential change, for example. In order to suppress the voltage change to within 10% of the maximum potential change, |Vdd×Cgd1/(Cgd1+Cp+Cgd3)-{Vreset(on)-Vreset(off)}×Cgd3/(Cgd3+Cp+Cgd1)|≦maximum potential change×0.1. Here, the maximum potential change is the amount of change in pixel electrode potential when a pressure of the maximum value of the pressure detection range set in the pressure sensor is applied from a state where no pressure is applied to the pressure sensor. For example, when the maximum potential change amount is 4 [V], |Vdd×Cgd1/(Cgd1+Cp+Cgd3)−{Vreset(on)−Vreset(off)}×Cgd3/(Cgd3+Cp+Cgd1)|≦0.4.

The measurement method is the same as in the third embodiment, and the detection method of the sensor array in the third embodiment can suitably use, for example, the signal detection circuit, drive detection circuit, and signal detection method of the first embodiment.

A specific example of FIG. 13 is shown in FIG. 14. On an insulating substrate 1, gate electrodes G1, G2, and G3 (G2 is connected to the scanning wiring 12, and G3 is connected to the reset wiring 13), a gate insulating film 3 is provided thereon, semiconductors SC1, SC2, and SC3 are provided thereon, source electrodes S1, S2, and S3 and drain electrodes D1, D2, and D3 are provided thereon (S1 is connected to D2 through the connection wiring 17, D3 is connected to the gate electrode G1 through the via wiring 18L provided in the opening of the gate insulating film 3, D1 is connected to the drain wiring 14, S2 is connected to the signal wiring 15, and S3 is connected to the common wiring 11), an interlayer insulating film 7 is provided thereon, and a pixel electrode 8 is provided thereon (the pixel electrode 8 is connected to the drain electrode D3 through the via wiring 18U provided in the opening of the interlayer insulating film 7). It further has a sensor portion 109 (for example, a pressure-sensitive medium 9) and a common electrode 10. The sensor portion 109 is in contact with or bonded to the pixel electrode 8.

An insulating etching stopper layer may be formed on the semiconductors SC1, SC2, and SC3, and contact layers having a lower resistance than the semiconductors SC1, SC2, and SC3 may be formed at the interfaces between the semiconductors SC1, SC2, and SC3 and the source electrodes S1, S2, and S3 and at the interfaces between the semiconductors SC1, SC2, and SC3 and the drain electrodes D1, D2, and D3.

Also, if the pixel electrode 8 is thick, there may be a gap in the area where the pixel electrode 8 is not present, or the gap may be filled with an insulating material.

In FIG. 14, the pixel electrode 8 also serves as the back gate electrode of the first thin film transistor. This provides a more stable operation than when the pixel electrode 8 is simply connected to the gate electrode G1 without covering the channel portion of the first thin film transistor. Although not shown in FIG. 14, a back gate electrode may be provided in the second thin film transistor and a common electrode potential, a GND potential, or a specific constant potential may be connected thereto. This provides a stable operation of the second thin film transistor. Similarly, a back gate electrode may be provided in the third thin film transistor and a pixel electrode potential, a common electrode potential, a GND potential, or a specific constant potential may be connected thereto. This provides a stable operation of the third thin film transistor.

The materials of each component are the same as in the third embodiment.

Figure 14 shows a bottom gate/top contact case, but the present disclosure is not limited to this and may also be top gate or bottom contact.

[Fifth embodiment]
A pixel circuit according to a fifth embodiment of the present disclosure is shown in FIG. 15. In FIG. 15, the sensor unit 109 (e.g., pressure-sensitive medium 9) is a type in which the potential difference changes depending on a stimulus (pressure, etc.). One end of the sensor unit 109 is connected to a common electrode 10, and the other end is connected to a gate electrode G1 of a first thin film transistor, a drain electrode D1 of the first thin film transistor is connected to a power supply Vdd via a drain wiring 14, a source electrode S1 of the first thin film transistor is connected to a drain electrode D2 of a second thin film transistor, a gate electrode G2 of the second thin film transistor is connected to a scanning wiring 12, and a source electrode S2 of the second thin film transistor is connected to a signal wiring 15. When a load resistor 20 in a detection circuit described later is included, the first thin film transistor is a drain ground circuit (source follower). Since the load resistor 20 is outside the array, a current flows through the signal wiring 15, so that the impedance is low and noise is unlikely to be mixed in. In addition, since the circuit is a common-drain (source follower) circuit, only the current is amplified and the voltage remains almost constant, so that the circuit is less susceptible to the effects of variations in the mobility and threshold value of the first thin film transistor.

In addition, the common wiring 11 is connected to the gate electrode G4 of the fourth thin film transistor, the drain electrode D4 of the fourth thin film transistor is connected to the power supply Vdd via the drain wiring 14, the source electrode S4 of the fourth thin film transistor is connected to the drain electrode D5 of the fifth thin film transistor, the gate electrode G5 of the fifth thin film transistor is connected to the scanning wiring 12, the source electrode S5 of the fifth thin film transistor is connected to the reference signal wiring 16, and when the load resistor 20 in the signal detection circuit is included, the fourth thin film transistor becomes a drain-grounded circuit (source follower).

By observing the difference between the signal circuit consisting of the sensor unit 109 and the first and second thin film transistors and the reference circuit consisting of the fourth and fifth thin film transistors, the mobility variation and threshold change of the first thin film transistor can be canceled by the mobility variation and threshold change of the fourth thin film transistor, and the mobility variation and mobility change of the second thin film transistor can be canceled by the mobility variation and threshold change of the fifth thin film transistor. This is because the variation and characteristic change are greatly influenced by the in-plane distribution, and therefore the variation and characteristic change of thin film transistors formed in the same pixel are similar. In particular, it is preferable to make the shape (channel width and channel length) of the first thin film transistor equal to the shape (channel width and channel length) of the fourth thin film transistor, and the shape (channel width and channel length) of the second thin film transistor equal to the shape (channel width and channel length) of the fifth thin film transistor.

The detection method of the sensor array in the fifth embodiment can suitably use, for example, the signal detection circuit, drive detection circuit, and signal detection method according to the second embodiment. In this case, the number of scanning wirings 12 of the sensor array is N, and the number of signal wirings 15 is M.

A pressure-sensitive medium 9 (a type in which the potential difference changes) is suitable as the sensor unit 109. However, it is also possible to use other pressure-sensitive media, displacement-sensitive media, temperature-sensitive media, etc. as the sensor unit 109.

In addition, when the potential of the drain line 14 is changed from 0 to Vdd immediately before measurement, the potential shift of the pixel electrode 8 should be set to |Vdd x Cgd1/(Cgd1 + Cp)| ≦ maximum potential change amount x 0.1, as in the third embodiment.

A specific example of Figure 15 is shown in Figure 16. On an insulating substrate 1, gate electrodes G1, G2, G4, G5 are provided (G2 and G5 are connected to a scanning wiring 12), a gate insulating film 3 is provided thereon, semiconductors SC1, SC2, SC4, SC5 are provided thereon, source electrodes S1, S2, S4, S5 and drain electrodes D1, D2, D4, D5 are provided thereon (S1 is connected to D2 via a connection wiring 17, S4 is connected to D5 via a connection wiring 17, D1 and D4 are connected to a drain wiring 14, S2 is connected to a signal wiring 15, and S5 is connected to a reference signal wiring 16), an interlayer insulating film 7 is provided thereon, and a pixel electrode 8 and a common wiring 11 are provided thereon (the pixel electrode 8 is connected to the gate electrode G1 via via wirings 18U and 18L provided in an opening of the interlayer insulating film 7 and an opening of the gate insulating film 3, and the common wiring 11 is connected to the gate electrode G4 via via wirings 18U and 18L provided in an opening of the interlayer insulating film 7 and an opening of the gate insulating film 3). The pixel electrode 8 further includes a sensor portion 109 (for example, a pressure-sensitive medium 9) and a common electrode 10. The sensor portion 109 is in contact with or bonded to the pixel electrode 8.

An insulating etching stopper layer may be formed on the semiconductors SC1, SC2, SC4, and SC5, and contact layers having a lower resistance than the semiconductors SC1, SC2, SC4, and SC5 may be formed at the interfaces between the semiconductors SC1, SC2, SC4, and SC5 and the source electrodes S1, S2, S4, and S5 and at the interfaces between the semiconductors SC1, SC2, SC4, and SC5 and the drain electrodes D1, D2, D4, and D5.

In addition, if the pixel electrode 8 is thick, the portion where the pixel electrode 8 is not present may have a gap or may be filled with an insulator. The common wiring 11 may or may not be in contact with the sensor portion 109.

In FIG. 16, the pixel electrode 8 is the back gate electrode of the first thin film transistor, and the common wiring 11 is the back gate electrode of the fourth thin film transistor. This results in a more stable operation than when the pixel electrode 8 is only connected to the gate electrode G1 without covering the channel portion of the first thin film transistor, or when the common wiring 11 is only connected to the gate electrode G4 without covering the channel portion of the fourth thin film transistor. In addition, although not shown in FIG. 16, a back gate electrode may be provided in the second thin film transistor, and a pixel electrode potential, a common electrode potential, a GND potential, or a specific constant potential may be connected thereto. This stabilizes the operation of the second thin film transistor. Similarly, a back gate electrode may be provided in the fifth thin film transistor, and a common electrode potential, a GND potential, or a specific constant potential may be connected thereto. This stabilizes the operation of the fifth thin film transistor.

The materials of each component are the same as in the third embodiment.

Figure 16 shows a bottom gate/top contact case, but the present disclosure is not limited to this and may also be top gate or bottom contact.

Sixth embodiment
A pixel circuit according to a sixth embodiment of the present disclosure is shown in Fig. 17. In Fig. 17, a third thin film transistor is further included in the pixel circuit of Fig. 15, and the drain electrode D3 of the third thin film transistor is connected to the pixel electrode 8, the source electrode S3 is connected to the common wiring 11, and the gate electrode G3 is connected to the reset wiring 13.

Before pressure measurement, a voltage (on voltage) that turns on the third thin film transistor is applied to the reset wiring 13 with no stimulus (pressure, etc.) being applied to the sensor unit 109. This connects the pixel electrode 8 to the common wiring 11 via the third thin film transistor, and the charge accumulated in the pixel electrode 8 can be set to zero. Then, a voltage (off voltage) that turns off the third thin film transistor is applied to the reset wiring 13, and the power supply Vdd is applied to the drain wiring 14.

When an off voltage is applied to the reset wiring 13 to turn off the third thin film transistor, the potential of the pixel electrode 8 shifts by ΔVp = (Vreset(off) - Vreset(on)) x Cgd3/(Cgd3 + Cp + Cgd1), and when the potential of the drain wiring 14 is changed from 0 to Vdd, the potential of the pixel electrode 8 shifts by ΔVp = Vdd x Cgd1/(Cgd1 + Cp + Cgd3), and the two have the effect of canceling each other out, as in the second embodiment. As in the second embodiment, it is sufficient if |Vdd x Cgd1/(Cgd1 + Cp + Cgd3) - {Vreset(on) - Vreset(off)} x Cgd3/(Cgd3 + Cp + Cgd1)| ≦ maximum potential change x 0.1.

The measurement method is the same as in the fifth embodiment, and the detection method of the sensor array in the sixth embodiment can suitably use, for example, the signal detection circuit, drive detection circuit, and signal detection method of the second embodiment.

A specific example of Figure 17 is shown in Figure 18. On an insulating substrate 1, gate electrodes G1, G2, G3, G4, G5 (G2 and G5 are connected to scanning wiring 12, and G3 is connected to reset wiring 13) are provided thereon, and a gate insulating film 3 is provided thereon, and semiconductors SC1, SC2, SC3, SC4, SC5 are provided thereon, and source electrodes S1, S2, S3, S4, S5 and drain electrodes D1, D2, D3, D4, D5 are provided thereon (S1 is connected to D2 via connection wiring 17, D3 is connected to gate electrode G1 via via wiring 18L provided in an opening in the gate insulating film 3, and S4 is connected to the connection wiring 18L). 17, D1 and D4 are connected to the drain wiring 14, S2 is connected to the signal wiring 15, S5 is connected to the reference signal wiring 16, and S3 is connected to the common wiring 11), has an interlayer insulating film 7 thereon, and has a pixel electrode 8 and a common wiring 11 thereon (the pixel electrode 8 is connected to the drain electrode D3 through a via wiring 18U provided in an opening of the interlayer insulating film 7, and the common wiring 11 is connected to the gate electrode G4 through via wirings 18U and 18L provided in openings of the interlayer insulating film 7 and the gate insulating film 3). It further has a sensor portion 109 (e.g., a pressure-sensitive medium 9) and a common electrode 10. The sensor portion 109 is in contact with or joined to the pixel electrode 8.

An insulating etching stopper layer may be provided on the semiconductors SC1, SC2, SC3, SC4, and SC5, and contact layers having a lower resistance than the semiconductors SC1, SC2, SC3, SC4, and SC5 may be provided at the interfaces between the semiconductors SC1, SC2, SC3, SC4, and SC5 and the source electrodes S1, S2, S3, S4, and S5 and at the interfaces between the semiconductors SC1, SC2, SC3, SC4, and SC5 and the drain electrodes D1, D2, D3, D4, and D5.

In addition, if the pixel electrode 8 is thick, the portion where the pixel electrode 8 is not present may have a gap or may be filled with an insulator. The common wiring 11 may or may not be in contact with the sensor portion 109.

The materials of each component are the same as in the third embodiment.

In FIG. 18, the pixel electrode 8 is the back gate electrode of the first thin film transistor, and the common wiring 11 is the back gate electrode of the fourth thin film transistor. This results in a more stable operation than when the pixel electrode 8 is only connected to the gate electrode G1 without covering the channel portion of the first thin film transistor, or when the common wiring 11 is only connected to the gate electrode G4 without covering the channel portion of the fourth thin film transistor. In addition, although not shown in FIG. 12, a back gate electrode may be provided in the second thin film transistor, and a pixel electrode potential, a common electrode potential, a GND potential, or a specific constant potential may be connected thereto. This stabilizes the operation of the second thin film transistor. Similarly, a back gate electrode may be provided in the third thin film transistor, and a pixel electrode potential, a common electrode potential, a GND potential, or a specific constant potential may be connected thereto. This stabilizes the operation of the third thin film transistor. Similarly, a back gate electrode may be provided in the fifth thin film transistor, and a common electrode potential, a GND potential, or a specific constant potential may be connected thereto. This stabilizes the operation of the fifth thin film transistor.

Figure 18 shows a bottom gate/top contact case, but the present disclosure is not limited to this and may also be top gate or bottom contact.

In addition, if the sensor unit 109 is oriented so that the potential on the pixel electrode 8 side increases when a positive stimulus (pressure, etc.) is applied, it is advisable to adjust the signal voltage when there is no stimulus to somewhere between 0 and +2 [V]. This allows a detection range of 5 to 3 V to be used when an AD converter with an input of 0 to +5 V is used for signal detection. If the sensor unit 109 is oriented so that the potential on the pixel electrode 8 side decreases when a positive stimulus (pressure, etc.) is applied, it is advisable to adjust the signal voltage when there is no stimulus to somewhere between +3 and +5 [V]. This allows a detection range of 3 to 5 V to be used when an AD converter with an input of 0 to +5 V is used.

In addition, if the sensor unit 109 is oriented so that the potential on the pixel electrode 8 side increases when a positive stimulus (pressure, etc.) is applied, it is advisable to adjust the voltage Vbase added by the differential amplifier circuit 24 to somewhere between 0 and +2 V. This allows a detection range of 5 to 3 V to be used when an AD converter with an input of 0 to +5 V is used. If the sensor unit 109 is oriented so that the potential on the pixel electrode 8 side decreases when a positive stimulus (pressure, etc.) is applied, it is advisable to adjust the voltage Vbase added by the differential amplifier circuit 24 to somewhere between +3 and +5 V. This allows a detection range of 3 to 5 V to be used when an AD converter with an input of 0 to +5 V is used.

[Seventh embodiment]
Based on FIG. 19, a health condition estimation system using the signal detection circuit or drive detection circuit of the first embodiment or the signal detection circuit or drive detection circuit of the second embodiment will be described. FIG. 19 is a block diagram showing an example of a care data collection and determination system of the present disclosure. The care data collection and determination system includes a care sensor device and a data collection and determination device. The care sensor device is a device in which a communication circuit is added to the signal detection circuit of the first or second embodiment, and includes a signal detection circuit, a communication circuit, a pressure-sensitive sensor array, a microcomputer, and a drive circuit. The communication circuit of the care sensor device is a circuit that communicates data with an external circuit, and is capable of wired communication and wireless communication, but wireless communication such as Bluetooth (registered trademark) and Wi-Fi (registered trademark) is particularly preferable, and it is further preferable to connect to the Internet. The data collection and determination device has a communication circuit, a computer, and a database, and (1) stores data detected by the care sensor device in the database as it is or after processing. At that time, the medical condition of the care recipient can also be stored together. (2) Using artificial intelligence, the big data in the database is analyzed by machine learning or the like to clarify the relationship between posture and medical condition. (3) The data detected by the care sensor device is compared with the data in the database to determine the condition of the patient.

One data collection and judgment device may be connected to only one care sensor device, or one data collection and judgment device may be connected to multiple care sensor devices. When connected to only one care sensor device, data exchange is easy, but the response speed of the care sensor device needs to be fast. Alternatively, the speed of the data collection and judgment device does not need to be very fast. When connected to multiple care sensor devices, data exchange becomes more complicated, but the operating speed of each care sensor device can be slow. Alternatively, the speed of the data collection and judgment device needs to be fast.

Also, in Figure 19, the computer and database are located within a single data collection and judgment device, but the computer and database may also communicate via a communication circuit.

An example of a care sensor device is shown in Figure 20. In Figure 20, the care sensor device 200 is shown visible on a bed 201, but in reality a sheet is placed on top of it and the person being cared for sleeps on it. The care sensor device 200 in Figures 20(a) and (b) has a large sheet-like sensor array 200A (e.g. a pressure sensor array) placed on the bed. 200G is a drive circuit, 200S is a signal detection circuit, and 200C is a control and communication circuit. The short side may be the drive side as in Figure 20(a), or the long side may be the drive side as in (b).

The care sensor device 200 in Fig. 20(c) has a plurality of band-shaped sensor arrays 200A, all of the short sides of the band-shaped sensor arrays 200A are connected to the signal detection circuit 200S, and adjacent long sides of the band-shaped sensor arrays 200A are connected to the drive wiring connection parts 200WG to connect all gate wirings to one drive circuit 200G, and has one control/communication circuit 200C. The care sensor device 200 in Fig. 20(d) has a plurality of small sheet-shaped sensor arrays 200A, and the signal wirings of the small sheet-shaped sensor arrays 200A are connected to each other with the signal wiring connection parts 200WS to connect to the signal detection circuit 200S, and the drive wirings of the small sheet-shaped sensor arrays 200A are connected to each other with the drive wiring connection parts 200WG to connect to one drive circuit 200G, and has one control/communication circuit 200C. In Fig. 20(c) and Fig. 20(d), the large sheet-shaped sensor array in Fig. 20(a) is replaced with multiple strip-shaped sensor arrays or multiple small sheet-shaped sensor arrays. The driving side and the signal side may be interchanged as in Fig. 20(b). These operate as one care sensor device 200.

The care sensor device 200 in FIG. 20(e) has a plurality of belt-shaped sensor arrays 200A, connects the short side of the belt-shaped sensor array 200A to a signal detection circuit 200S, connects the long side of each belt-shaped sensor array 200A to a plurality of driving circuits 200G, and has a plurality of control and communication circuits 200C. The care sensor device 200 in FIG. 20(f) has a plurality of small sheet-shaped sensor arrays 200A, connects the signal wiring of the small sheet-shaped sensor arrays 200A with a signal wiring connecting part 200WS to form a belt-shaped set and connects it to the signal detection circuit 200S, connects each belt-shaped set to a plurality of driving circuits 200G, and has a plurality of control and communication circuits 200C. FIG. 20(e) and FIG. 20(f) operate as a plurality of care sensor devices 200.

In addition, when a sensor array is applied to determining posture, it is possible to make a determination even if the stimulus values (pressure, etc.) of all pixels are not accurately measured. Even if a malfunction occurs in the detection section of one pixel, resulting in abnormal data, it is possible to make a determination by interpolating from the data of the surrounding pixels. Even if a malfunction occurs in the detection section of multiple pixels, resulting in abnormal data, it is possible to make a determination by interpolating from the data of the surrounding pixels. In this case, if the defective pixels are dispersed, it is easier to interpolate data compared to when they are densely packed. However, even when they are densely packed, a certain amount of interpolation is possible. Note that the sensor array is not limited to pressure sensors. Specifically, a displacement sensor or a temperature sensor can be used as a sensor array. In other words, it is also applicable to a displacement sensor array or a temperature sensor array. Furthermore, it is also applicable to a composite sensor array equipped with both a temperature sensor and a pressure sensor, for example.

Furthermore, as shown in FIG. 22, it is preferable to provide a current limiting circuit 40 for the drain wiring 14. When a short circuit occurs between the drain wiring 14 and other wiring (scanning wiring 12, signal wiring 15, reference signal wiring 16, common electrode 37, etc.) in the array, excessive current is prevented from flowing. In this case, as shown in FIG. 22(a), the power supply may pass through one current limiting circuit 40 and then branch to be connected to all the drain wirings 14, but in that case, an abnormality in one place will cause the voltage of all the drain wirings 14 to drop, and the entire sensor array will show an abnormal value. Therefore, as shown in FIG. 22(b), it is preferable to branch the power supply and connect each of the branches to each individual drain wiring 14 after passing through a current limiting circuit 40. Since the drain wiring 14 is usually provided for each column or row, it is preferable to provide one current limiting circuit 40 for each drain wiring 14. In this case, an abnormality in one place will cause the voltage of one drain wiring 14 to drop, and one column or one row of sensors will show an abnormal value, but the abnormality in one column or one row can be corrected by interpolation. Alternatively, as shown in Fig. 22(c), each of the multiple current limiting circuits 40 can be assigned to multiple column wirings or row wirings. In this case, as shown in Fig. 22(d), by not placing the column wirings or row wirings assigned to one current limiting circuit 40 adjacent to each other, and providing column wirings or row wirings assigned to another current limiting circuit 40 between them, it is possible to prevent an abnormality in one location from becoming a continuous abnormality in multiple columns or rows, and to enable interpolation. Note that the current limiting circuit 40 is not limited to the circuit shown in Fig. 22(a), and may be a current limiting circuit of another type.

As described above, by applying the signal detection circuit or drive detection circuit of the first embodiment, or the signal detection circuit or drive detection circuit of the second embodiment, a nursing care data collection and judgment system capable of estimating health status can be provided.

Example 1
The signal detection circuit shown in Fig. 1 was fabricated. The first switching circuit 101 was an 8-input, 1-output analog multiplexer, the load resistor 20 was a 1 MΩ metal film resistor, the voltage detection amplifier 53 was a voltage follower using an operational amplifier, the second switching circuit 102 was an 8-input, 1-output analog multiplexer, and the AD converter 25 had an input of 0 to +5 V and an output of 0 to 255 levels (8 bits). This circuit has M ₁ = 8, M ₂ = 8, and L = 8, and corresponds to a sensor array having M = 64 signal wirings 15. An oscillation prevention circuit was built into the voltage detection amplifier 53, and an AD converter input protection circuit was provided on the output side of the voltage detection amplifier 53.

A microcomputer and a 3-bit counter were used to control the first switching circuit 101, which also controlled the second switching circuit 102 and the AD converter 25, to detect the signal of the 1 row x 64 column pressure sensor array. The measurement time of the AD converter 25 was set to (preparation time 104 μs + actual measurement time 52 μs) = 156 μs, the time constant of the response of the output of the second switching circuit 102 was about 3 μs, and the time constant of the response of the output of the first switching circuit 101 was about 500 μs. Since the time constant of the response of the output of the first switching circuit 101 was smaller than (M ₂ -1) × AD converter measurement time = 1092 μs, the signal detection method of Figure 5 allowed for highly accurate measurement after the signal stabilized.

Example 2
The drive detection circuit of Fig. 3 was fabricated by adding the microcomputer and counter used in Example 1 as a control circuit 5 and a counter 49 to the signal detection circuit of Example 1, and further adding a drive circuit 6. The drive circuit outputs +15 V as an on-voltage or -15 V as an off-voltage.

Using this drive detection circuit, signals from an 8-row, 64-column pressure sensor array were detected using the signal detection method of Fig. 5. The measurement time of the AD converter 25 was set to (preparation time 104 µs + actual measurement time 52 µs) = 156 µs, the time constant of the response of the output of the second switching circuit 102 was about 3 µs, and the time constant of the response of the output of the first switching circuit 101 was about 500 µs. Since the time constant of the response of the output of the first switching circuit 101 was smaller than (M ₂ - 1) × AD converter measurement time = 1092 µs, the signal detection method of Fig. 5 allowed for highly accurate measurement after the signal stabilized.

Example 3
The signal detection circuit of FIG. 7 was fabricated. The first switching circuit 101 and the third switching circuit 103 were each a set of analog multiplexers (8 inputs, 1 output x 2 sets), the load resistors 20 and 21 were 1 MΩ metal film resistors, the voltage detection amplifiers 53 and 54 were non-inverting amplifier circuits using operational amplifiers, the differential amplifier circuit 24 was a circuit using an operational amplifier, the second switching circuit 102 was an 8-input, 1-output analog multiplexer, and the AD converter 25 was an input of 0 to +5 V and an output of 0 to 255 levels (8 bits). This circuit corresponds to a sensor array having M ₁ = 8, M ₂ = 8, and L = 8, and M = 64 signal wirings and 64 reference signal wirings. An oscillation prevention circuit was built into the voltage detection amplifiers 53 and 54, and an AD converter input protection circuit was provided on the output side of the voltage detection amplifiers 53 and 54.

A microcomputer and a 3-bit counter were used to control the first switching circuit 101 and the third switching circuit 103, and the same microcomputer also controlled the second switching circuit 102 and the AD converter 25 to detect the signal of the 1 row x 64 column pressure sensor array. The measurement time of the AD converter 25 was set to (preparation time 104 μs + actual measurement time 52 μs) = 156 μs, the time constant of the response of the output of the second switching circuit 102 was about 3 μs, and the time constant of the response of the output of the first switching circuit 101 was about 500 μs. Since the time constant of the response of the output of the first switching circuit 101 was smaller than (M ₂ -1) × AD converter measurement time = 1092 μs, the signal detection method of FIG. 9 allowed for highly accurate measurement after the signal stabilized.

Example 4
The drive detection circuit of Fig. 8 was fabricated by adding the microcomputer and counter used in Example 3 to the signal detection circuit of Example 3, and further adding a drive circuit 6. The drive circuit 6 outputs +15 V as an on-voltage or -15 V as an off-voltage.

Using this drive detection circuit, signals from an 8-row, 64-column pressure sensor array were detected by the signal detection method of Fig. 9. The measurement time of the AD converter 25 was set to (preparation time 104 µs + actual measurement time 52 µs) = 156 µs, the time constant of the response of the output of the second switching circuit 102 was about 3 µs, and the time constant of the response of the output of the first switching circuit 101 and the third switching circuit 103 was about 500 µs. Since the time constant of the response of the output of the first switching circuit 101 and the third switching circuit 103 is smaller than (M ₂ - 1) × AD converter measurement time = 1092 µs, the signal detection method of Fig. 9 allowed for highly accurate measurement after the signal stabilized.

Example 5
The sensor array shown in FIG. 12 was fabricated. A PET film on a glass substrate was used as the insulating substrate 1, and Mo was deposited, a resist was deposited, pattern-exposed, developed, etched, and the resist was removed to form gate electrodes G1 and G2 and scanning wiring 12. Next, a photosensitive acrylic film was deposited, pattern-exposed, and developed to form a gate insulating film 3 with an opening. In addition, amorphous InGaZnO was deposited, a resist was deposited, pattern-exposed, developed, etched, and the resist was removed to form semiconductor patterns SC1 and SC2. Then, a _SiO2 pattern was formed as an etching stopper layer on the channel portions of the semiconductor patterns SC1 and SC2 (not shown).

Furthermore, a Mo film was formed, a resist film was formed, the pattern was exposed, developed, etched, and the resist was removed to form source electrodes S1, S2, drain electrodes D1, D2, connection wiring 17 (between S1 and D2), signal wiring 15, drain wiring 14, and via wiring 18L (the lower half between the pixel electrode and G1).

Then, a photosensitive acrylic film was formed, pattern exposed, and developed to form an interlayer insulating film 7 with an opening. Next, a Mo film was formed, a resist film was formed, pattern exposed, developed, etched, and the resist was removed to form a pixel electrode 8 and a via wiring 18U (the upper half between the pixel electrodes 8 and G1). At this time, the pixel electrode 8 was connected to the gate electrode G1 by the via wirings 18U and 18L.

Furthermore, a pressure-sensitive medium (polyvinylidene fluoride-trifluoroethylene copolymer, polarized) with Mo attached to the entire surface on one side was placed so that the pressure-sensitive medium side was in contact with the pixel electrode 8 to form the sensor section 109 (pressure-sensitive medium 9) and common electrode 10. The glass substrate was then peeled off from the PET film, which was the insulating substrate 1. As the pixel electrode 8 was thin, the sensor section 109 (pressure-sensitive medium 9) was in contact with the interlayer insulating film 7 in areas other than the pixel electrode 8, with almost no gaps.

Here, the gate-drain capacitance of the first thin-film transistor (including the capacitance between the pixel electrode and the drain wiring) Cgd1 = 1.53 pF, and the capacitance between the pixel electrode 8 and the common electrode 10 Cp = 63.1 pF.

Using the detection circuit of Figure 23, +1V was applied to the common electrode 10, +10V to the drain wiring 14, an on voltage of +15V to one of the scanning wirings 12, and an off voltage of -15V to the others, to obtain a pressure-dependent signal for one pixel. Pressure-dependent signals for one row were obtained by switching the analog switch 22. The same operation was performed by changing the on voltage position of the scanning wiring 12, to obtain pressure-dependent signals for all pixels. The pressure-dependent signal can be determined from the pressure-dependent signal. Furthermore, since the potential change of the pixel electrode 8 when Vdd is applied is 0.24V, and the maximum potential change of the pressure-sensitive medium 9 (at a pressure of 800kPa) is 4V, the error due to the potential change of the pixel electrode 8 when Vdd is applied is sufficiently small at 6% of the maximum potential change.

Example 6
The sensor array of FIG. 14 was fabricated. A polyimide film on a glass substrate was used as the insulating substrate 1, and Mo was deposited, a resist was deposited, pattern-exposed, developed, etched, and the resist was removed to form gate electrodes G1, G2, and G3, scanning wiring 12, and reset wiring 13. Next, a photosensitive acrylic was deposited, pattern-exposed, and developed to form a gate insulating film 3 with an opening. In addition, amorphous InGaZnO was deposited, a resist was deposited, pattern-exposed, developed, etched, and the resist was removed to form semiconductor patterns SC1, SC2, and SC3. Then, a _SiO2 pattern was formed as an etching stopper layer on the channel portions of the semiconductor patterns SC1, SC2, and SC3 (not shown).

Furthermore, source electrodes S1, S2, S3, drain electrodes D1, D2, D3, connection wiring 17 (between S1 and D2), via wiring 18L (between D3 and G1), signal wiring 15, and drain wiring 14 were formed by depositing Mo, depositing a resist, pattern exposing, developing, etching, and removing the resist.

Then, photosensitive acrylic was deposited, pattern-exposed, and developed to form an interlayer insulating film 7 with an opening. Next, Ag paste was screen-printed to form the pixel electrode 8 and via wiring 18U (between pixel electrode 8 and D3). At this time, the pixel electrode 8 was connected to the drain electrode D3 and gate electrode G1 by the via wiring 18U and 18L.

Furthermore, a pressure-sensitive medium (polyvinylidene fluoride trifluoroethylene copolymer, polarized) with Mo attached to the entire surface on one side was placed so that the pressure-sensitive medium side was joined to the pixel electrode 8 to form the sensor section 109 (pressure-sensitive medium 9) and common electrode 10. The glass substrate was also peeled off from the polyimide film that constituted the insulating substrate 1. As the pixel electrode 8 was thick, the sensor section 109 (pressure-sensitive medium 9) was not in contact with the interlayer insulating film 7, and there was a gap where the pixel electrode 8 was not present.

Here, the gate-drain capacitance of the first thin film transistor (including the capacitance between the pixel electrode and the drain wiring) Cgd1 = 1.53 pF, the gate-drain capacitance of the third thin film transistor (including the capacitance between the pixel electrode and the drain wiring) Cgd3 = 0.69 pF, and the capacitance Cp between the pixel electrode 8 and the common electrode 10 = 63.1 pF.

Using the detection circuit in Figure 24, first, an on-voltage of +15V was applied to the reset wiring 13 with +1V applied to the common electrode 10 and 0V applied to the drain wiring 14. Next, the potential of the reset wiring 13 was set to the off-voltage of -15V, and the potential of the drain wiring 14 was set to +15V.

An on voltage of +15V was applied to one of the scanning wirings 12, and an off voltage of -15V to the other, to obtain a pressure-dependent signal for one pixel. A pressure-dependent signal for one row was obtained by switching the analog switch 22. The on voltage position of the scanning wiring 12 was changed and the same operation was performed to obtain pressure-dependent signals for all pixels. The pressure-dependent signal can be determined from the pressure-dependent signal. Furthermore, since the potential change of the pixel electrode 8 when Vreset is off and Vdd is applied is 0.027V, and the maximum potential change of the pressure-sensitive medium 9 (at a pressure of 800kPa) is 4V, the error due to the potential change of the pixel electrode 8 when Vreset is off and Vdd is applied is sufficiently small at 0.7% of the maximum potential change.

(Example 7)
The sensor array of FIG. 16 was produced. A PET film on a glass substrate was used as the insulating substrate 1, and Mo was deposited, resist was deposited, pattern exposed, developed, etched, and resist removed to form gate electrodes G1, G2, G4, and G5 and scanning wiring 12. Next, a photosensitive acrylic was deposited, pattern exposed, and developed to form a gate insulating film 3 with an opening. In addition, amorphous InGaZnO was deposited, resist was deposited, pattern exposed, developed, etched, and resist removed to form semiconductor patterns SC1, SC2, SC4, and SC5. Then, a _SiO2 pattern was formed as an etching stopper layer on the channel portions of the semiconductor patterns SC1, SC2, SC4, and SC5 (not shown).

Furthermore, a Mo film was formed, a resist film was formed, the pattern was exposed, developed, etched, and the resist was removed to form source electrodes S1, S2, S4, S5, drain electrodes D1, D2, D4, D5, connection wiring 17 (between S1 and D2), connection wiring 17 (between S4 and D5), signal wiring 15, reference signal wiring 16, drain wiring 14, common wiring 11, via wiring 18L (the lower half between pixel electrodes 8 and G1), and via wiring 18L (the lower half between common wiring 11 and G4).

Then, photosensitive acrylic was deposited, pattern-exposed, and developed to form an interlayer insulating film 7 with an opening. Next, Ag paste was screen-printed to form the pixel electrode 8, common wiring 11, via wiring 18U (the upper half between pixel electrodes 8 and G1), and via wiring 18U (the upper half between common wiring 11 and G4). At this time, the pixel electrode 8 was connected to the gate electrode G1, and the common wiring 11 was connected to the gate electrode G4.

Furthermore, a pressure-sensitive medium (polyvinylidene fluoride trifluoroethylene copolymer, polarized) with Mo attached to the entire surface on one side was placed so that the pressure-sensitive medium side was joined to the pixel electrode 8 to form the sensor section 109 (pressure-sensitive medium 9) and the common electrode 10. The glass substrate was also peeled off from the PET film, which was the insulating substrate 1.

Here, the gate-drain capacitance of the first thin-film transistor (including the capacitance between the pixel electrode and the drain wiring) Cgd1 = 1.53 pF, and the capacitance between the pixel electrode 8 and the common electrode 10 Cp = 63.1 pF.

Using the detection circuit of FIG. 25, +1V was applied to the common electrode 10, +10V to the drain wiring 14, an on voltage of +15V to one of the scanning wirings 12, and an off voltage of -15V to the others, to obtain a pressure-dependent signal for one pixel. The analog switch 22 was switched to obtain a pressure-dependent signal for one row. The same operation was performed by changing the on voltage position of the scanning wiring 12, to obtain pressure-dependent signals for all pixels. The pressure-dependent signal can be determined from the pressure-dependent signal. In addition, the potential change of the pixel electrode 8 when Vdd is applied is 0.24V, and the maximum potential change of the pressure-sensitive medium 9 (at a pressure of 800 kPa) is 4V, so the error due to the potential change of the pixel electrode 8 when Vdd is applied is 6% of the maximum potential change, which is sufficiently small. Note that the Vbase of the detection circuit was set to 0.5 [V].

(Example 8)
The sensor array of FIG. 18 was produced. A polyimide film on a glass substrate was used as the insulating substrate 1, and Mo was deposited, resist was deposited, pattern exposed, developed, etched, and resist removed to form gate electrodes G1, G2, G3, G4, and G5, scanning wiring 12, and reset wiring 13. Next, a photosensitive acrylic was deposited, pattern exposed, and developed to form a gate insulating film 3 with an opening. In addition, amorphous InGaZnO was deposited, resist was deposited, pattern exposed, developed, etched, and resist removed to form semiconductor patterns SC1, SC2, SC3, SC4, and SC5. Then, a _SiO2 pattern was formed as an etching stopper layer on the channel portions of the semiconductor patterns SC1, SC2, SC3, SC4, and SC5 (not shown).

Furthermore, Mo was deposited, a resist was deposited, the pattern was exposed, developed, etched, and the resist was removed to form source electrodes S1, S2, S3, S4, S5, drain electrodes D1, D2, D3, D4, D5, connection wiring 17 (between S1 and D2), via wiring 18L (between D3 and G1), connection wiring 17 (between S4 and D5), signal wiring 15, drain wiring 14, and via wiring 18L (the lower half of the wiring between common wiring 11 and G4).

Then, photosensitive acrylic was deposited, pattern-exposed, and developed to form an interlayer insulating film 7 with an opening. Next, Ag paste was screen-printed to form the pixel electrode 8, via wiring 18U (between pixel electrode 8 and D1), common wiring 11, and via wiring 18U (the upper half between common wiring 11 and G4). At this time, the pixel electrode 8 was connected to the drain electrode D3 and gate electrode G1, and the common wiring 11 was connected to the gate electrode G4.

Furthermore, a pressure-sensitive medium (polyvinylidene fluoride trifluoroethylene copolymer, polarized) with Mo attached to the entire surface on one side was placed so that the pressure-sensitive medium side was joined to the pixel electrode 8 to form the sensor section 109 (pressure-sensitive medium 9) and the common electrode 10. The glass substrate was also peeled off from the polyimide film, which was the insulating substrate 1.

Here, the gate-drain capacitance of the first thin film transistor (including the capacitance between the pixel electrode and the drain wiring) Cgd1 = 1.53 pF, the gate-drain capacitance of the third thin film transistor (including the capacitance between the pixel electrode and the drain wiring) Cgd3 = 0.69 pF, and the capacitance between the pixel electrode 8 and the common electrode 10 Cp = 63.1 pF.

Using the detection circuit in Figure 26, first, an on-voltage of +15V was applied to the reset wiring 13 with +1V applied to the common electrode 10 and 0V applied to the drain wiring 14. Next, the potential of the reset wiring 13 was set to the off-voltage of -15V, and the potential of the drain wiring 14 was set to +15V.

An on-voltage of +15V was applied to one of the scanning wirings 12, and an off-voltage of -15V was applied to the other, to obtain a signal on the pressure-sensitive side of one pixel. A signal on the non-pressure-sensitive side was obtained by switching the analog switch 22. Furthermore, signals on the pressure-sensitive side and non-pressure-sensitive side for one row were obtained by switching the analog switch 22. The same operation was performed by changing the on-voltage position of the scanning wiring 12, and signals on the pressure-sensitive side and non-pressure-sensitive side of all pixels were obtained. The pressure of each pixel can be determined from the value obtained by subtracting the non-pressure-sensitive side signal from the pressure-sensitive side signal. In addition, the potential change of the pixel electrode 8 when Vreset is off and Vdd is applied is 0.027V, and the maximum potential change of the pressure-sensitive medium 9 (at a pressure of 800 kPa) is 4V, so the error due to the potential change of the pixel electrode 8 when Vreset is off and Vdd is applied is 0.7% of the maximum potential change, which is sufficiently small. Note that Vbase of the detection circuit is set to 1.0 [V].

(Comparative Example 1)
The signal detection circuit shown in Fig. 30 was created. The switching circuit 100 uses eight 8-input, 1-output analog multiplexers, the load resistors 122 are 1 MΩ metal film resistors, the voltage detection amplifiers 123 are voltage followers using operational amplifiers, and the AD converter 124 has an input of 0 to +5 V and an output of 0 to 255 levels (8 bits). This circuit uses 64 load resistors 122 and voltage detection amplifiers 123. This circuit corresponds to a sensor array having 64 signal wirings 15.

A microcomputer was used to control the switching circuit 100, which also controlled the AD converter 124, to detect the signal of a 1-row, 64-column pressure sensor array. The measurement time of the AD converter 124 was set to (preparation time 104 μs + actual measurement time 52 μs) = 156 μs, and the response time constant of the output of the switching circuit 100 was approximately 500 μs. Since the response time constant of the output of the switching circuit 100 was larger than the AD converter measurement time = 156 μs, the signal was unstable and the measurement accuracy was poor.

(Comparative Example 2)
Using the signal detection circuit of Example 2, signals from a pressure sensor array with 8 rows and 64 columns were detected by the signal detection method of Fig. 4. The measurement time of the AD converter 25 was set to (preparation time 104 μs + actual measurement time 52 μs) = 156 μs, the time constant of the response of the output of the second switching circuit 102 was about 3 μs, and the time constant of the response of the output of the first switching circuit 101 was about 500 μs. Since the time constant of the response of the output of the first switching circuit 101 was larger than the AD converter measurement time = 156 μs, the signal was not stable and the measurement accuracy was poor when using the signal detection method of Fig. 4.

The present disclosure can be used as a signal detection circuit or a drive detection circuit for various sensor arrays. It can also be used for various sensor arrays that use a sensor unit in which the potential difference changes. It can also be used for sensor systems including health condition estimation systems.

1 ... insulating substrate G1, G2, G3, G4, G5 ... gate electrode 3 ... gate insulating film SC1, SC2, SC3, SC4, SC5 ... semiconductor pattern S1, S2, S3, S4, S5 ... source electrode D1, D2, D3, D4, D5 ... drain electrode 5 ... control circuit 6 ... drive circuit 7 ... interlayer insulating film 8 ... pixel electrode 9 ... pressure-sensitive medium (type in which potential difference changes)
10... common electrode 11... common wiring 12... scanning wiring 13... reset wiring 14... drain wiring 15... signal wiring 16... reference signal wiring 17 (S1-D2, S4-D5)... connection wiring 18L, 18U... via wiring 20, 21... load resistor 22... analog switch 24... differential amplifier circuit 25... analog-digital conversion circuit (AD converter)
31 thin film transistor 32 scanning wiring 33 signal wiring 36 power supply wiring 38 TFT
39... Pressure-sensitive medium (resistance change type)
40: current limiting circuit 41: first thin film transistor 42: second thin film transistor 43: drain resistor 44: scanning wiring 45: signal wiring 48: control signal (digital wiring)
Reference numerals 49, 53, 54, voltage detection amplifier 100, switching circuit 101, first switching circuit 102, second switching circuit 103, third switching circuit 109, sensor unit 115, signal wiring 122, load resistor 123, voltage detection amplifier 124, AD converter 125, control circuit 126, drive circuit 127, scanning wiring 130, pressure-sensitive medium (resistance-changing type)
140 ... Inorganic pressure-sensitive medium (type in which potential difference changes)
200 ... Nursing care sensor device 200A ... Pressure sensor array 200G ... Driving circuit 200S ... Signal detection circuit 200C ... Control and communication circuit 200WG ... Drive wiring connection part 200WS ... Signal wiring connection part 201 ... Bed T1 ... TFT1
T2...TFT2
T3... TFT3
T4... TFT4

Claims (5)

A plurality of signal wirings;
A plurality of scanning wirings intersecting the signal wirings;
A plurality of reference signal wirings parallel to the signal wirings;
a plurality of pixel sections provided corresponding to the intersections of the signal lines and the scanning lines, each pixel section including a pixel electrode, a first thin film transistor, a second thin film transistor, a fourth thin film transistor, and a fifth thin film transistor;
a drain wiring for supplying power to a drain electrode of the first thin film transistor;
a sensor portion connected to the pixel electrode;
a common electrode connected to the sensor unit;
a common wiring for supplying power to a gate electrode of the fourth thin film transistor;
the pixel electrode is connected to the gate electrode of the first thin film transistor;
a drain electrode of the first thin film transistor is connected to the drain wiring;
A source electrode of the first thin film transistor is connected to a drain electrode of the second thin film transistor;
A gate electrode of the second thin film transistor is connected to the scanning line,
a source electrode of the second thin film transistor is connected to the signal line;
A gate electrode of the fourth thin film transistor is connected to the common wiring;
A drain electrode of the fourth thin film transistor is connected to the drain wiring;
A source electrode of the fourth thin film transistor is connected to a drain electrode of the fifth thin film transistor;
A gate electrode of the fifth thin film transistor is connected to the scanning line,
A source electrode of the fifth thin film transistor is connected to the reference signal wiring. the pixel portion further includes a third thin film transistor,
the sensor array has a common wiring for supplying power to a source electrode of the third thin film transistor, and a reset wiring for supplying power to a gate electrode of the third thin film transistor;
2. The sensor array of claim 1, wherein a drain electrode of the third thin film transistor is connected to the pixel electrode, a source electrode of the third thin film transistor is connected to the common wiring, and a gate electrode of the third thin film transistor is connected to the reset wiring. 3. The sensor array according to claim 1 , wherein the sensor portion is an organic piezoelectric material. 4. The sensor array according to claim 3, wherein the first to fifth thin film transistors are provided on an insulating substrate, each having a gate electrode, a gate insulating film, a semiconductor, a source electrode, and a drain electrode, an interlayer insulating film is provided on the first to fifth thin film transistors, the pixel electrode is provided on the interlayer insulating film on at least the first thin film transistor, and the insulating substrate, the gate insulating film, and the interlayer insulating film are mainly composed of an organic insulator. 5. The sensor array of claim 4 , wherein the pixel electrode is a mixture of conductive particles and an organic binder.

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