JP3545389B2 - Surface shape recognition sensor device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a surface shape recognition sensor device, and more particularly to a surface shape recognition sensor device that detects minute irregularities such as a human fingerprint and an animal nose pattern.
[0002]
[Prior art]
As an application example of the surface shape recognition sensor device that detects the surface shape of a detection target, many fingerprint sensors that detect a fingerprint pattern have been proposed. For example, “ISSCC DIGEST OF TECHNICAL PAPERS” FEBRUARY 1998 pp. 284-285.
In this method, a sensor electrode is provided inside a two-dimensionally arranged cell (hereinafter referred to as a sensor cell) on an LSI chip, and is formed between the sensor electrode and the skin of a finger touched via an insulating film. It detects the capacitance and detects the concavo-convex pattern of the fingerprint. Since the value of the capacitance formed by the unevenness of the fingerprint differs, the unevenness of the fingerprint can be sensed by detecting the difference in the capacitance.
[0003]
Further, a surface shape recognition sensor device having means for individually adjusting the detection sensitivities of a plurality of sensor circuits has been proposed.
FIG. 10 shows an example of a use state of a surface shape recognition sensor device having such a detection sensitivity adjustment function. This surface shape recognition sensor device is constituted by a large number of sensor cells adjacent to each other, and is typically constituted by a large number of sensor cells 11 arranged two-dimensionally (in an array or a lattice).
By bringing a detection target such as a finger 13 into contact with a sensor surface 12 of the surface shape recognition sensor device 10, the detection target surface (here, the concave and convex shape of the fingerprint) 14 is individually detected by each sensor cell 11, and the detection target is detected. Two-dimensional data indicating the surface shape is output.
[0004]
FIG. 11 shows an overall configuration diagram of a conventional surface shape recognition sensor device.
Each sensor cell 11 is arranged in a two-dimensional matrix of p rows × q columns, and is connected to word lines WL1 to WLp for selectively controlling the sensor cell 11 and data lines DL1 to DLq for transmitting the output of the sensor cell 11, respectively. They are connected in a grid.
A decoder 20 and an A / D conversion circuit 30 are provided around these sensor cells 11. The decoder 20 controls a word line according to the input address signal ADR. The A / D conversion circuit 30 converts an analog signal input from the data line into a digital signal and outputs the digital signal.
[0005]
As described above, in the surface shape recognition sensor device 10, any one of the plurality of sensor cells 11 is sequentially selected by the decoder 20, and the analog output of these sensor cells 11 is converted into the digital output by the A / D conversion circuit 30. The configuration 11 also serves as the A / D conversion circuit 30. As a result, an increase in the circuit scale is suppressed, and analog outputs from a large number of sensor cells 11 are efficiently converted to digital outputs.
[0006]
On the other hand, the surface shape recognition sensor device 10 has a function of adjusting the sensitivity of each sensor cell 11 (hereinafter, referred to as calibration) in order to make the characteristics of each sensor cell 11 caused by the manufacturing process, that is, the variation of the detection sensitivity uniform. Have.
In the conventional surface shape recognition sensor device 10, calibration is performed by connecting the calibration signal lines CL1 to CLp to the plurality of sensor cells 11 in the same manner as the word lines WL1 to WLp, and setting any one of the calibration signal lines to the active state. One of the plurality of sensor cells is sequentially selected from the application control circuit 40, and calibration is sequentially performed on the selected sensor cells.
[0007]
FIG. 12 shows a block diagram of a conventional sensor cell. The sensor cell 11 includes a detection element 1, a sensor circuit 2, a calibration circuit 3, and a selection circuit 4.
The detection element 1 is an element for converting a surface shape into an electric quantity. The sensor circuit 2 measures an electric quantity of the detecting element which changes according to the surface shape, and converts the electric quantity into a time signal having a pulse width corresponding to the electric quantity by an internal voltage-time conversion circuit (hereinafter referred to as a VT conversion circuit) 21. And outputs the output signal 2A.
The calibration circuit 3 is a circuit for individually adjusting (sensitivity adjustment) the detection sensitivity of the sensor circuit 2 of the sensor cell 11 for each sensor cell. The selection circuit 4 is a circuit that activates the sensor cell 11 based on the active state of the word line WL or the calibration signal from the calibration signal line CL.
[0008]
When the detection sensitivity in the sensor circuit 2 of each sensor cell 11 is calibrated, a reference sample having no unevenness is detected by the sensor as an object to be measured, or the detection is performed without placing anything on the sensor surface. The same measurement value is detected by the sensor cell.
The output signal 2A from each sensor cell 11 is input to the calibration circuit 3 of the sensor cell. The calibration circuit 3 includes a load circuit 31, a counter circuit (n bits) 32, and a time signal comparison circuit 33.
[0009]
In the time signal comparison circuit 33, the output signal 2A is compared with a reference pulse signal 3A having a pulse width corresponding to a desired detection sensitivity. Then, a comparison result having a pulse width of a time difference between the two is input to the counter circuit (n bits) 32 as a counter input signal 3B.
The counter circuit 32 performs a new counter operation based on the counter input signal 3B. As a result, the count data in the counter circuit 32 is sequentially updated, and the n load elements Z provided in the load circuit 31 are updated based on the count data.₁~ Z_nIs connected to the sensor circuit 2, and the detection sensitivity of the sensor circuit 2 is adjusted.
[0010]
Load element Z of load circuit 31₁~ Z_nA load element that can be controlled between an active state and an inactive state may be used. FIG. 13 shows an example of a load element that can be controlled between an active state and an inactive state. FIG. 13A shows an example of a capacitive load element, and FIG. 13B shows an example of a resistive load element. When the capacitance formed between the finger surface 14 and the sensor electrode 1B is used as the electric quantity, a load element as shown in FIG. 13A may be used, and the electric quantity between the finger surface 14 and the sensor electrode 1B may be used. In the case of using the contact resistance formed as described above, a load element as shown in FIG.
Such an operation is performed in each sensor cell 11 by the number of adjustment stages, for example, excluding a state where all the load elements Z are not selected.ⁿThe detection sensitivity of each sensor circuit 2 is adjusted by repeating -1 time, and the performance of each sensor cell is made uniform.
[0011]
As shown in FIG. 12, the detection element 1 is realized by a sensor electrode 1B formed on an insulating layer 16 and covered with a passivation film 15, and a static electricity formed between the finger surface 14 and the sensor electrode 1B as an electric quantity. Electric capacity C_fIs used.
The sensor circuit 2 includes a Pch MOSFET Q₁, NchMOSFET Q₂, A constant current source I and a VT conversion circuit 21. C_p0Is the parasitic capacitance.
[0012]
FIG. 14 is a timing chart showing the detection operation of the sensor cells.
Before time T1, the sensor circuit control signal / PRE (PRE bar) is set to the power supply voltage V_DDControlled by Q₁Is turned off, the sensor circuit control signal RE is controlled to a voltage of 0 V, and Q₂Is off and node N₁Is 0V.
At time T1, signal / PRE is controlled to 0V and Q₁Turns on and node N₁Is V_DDTo rise. At time T2, signal / PRE and signal RE become V_DDIs controlled to Q₁Turns off and Q₂Turns on. Thereby, the capacitance C_fIs discharged.
[0013]
Therefore, the capacitance C_fN at a speed dependent on₁Is gradually lowered, and at time T3 after a predetermined time Δt has elapsed from time T2, the signal RE is controlled to 0 V and Q₂Is turned off, the node N₁Then the capacitance C_fPotential V according to_DD−ΔV is maintained, and this is output to the VT conversion circuit 21.
[0014]
The VT conversion circuit 21 includes a constant current source I_VT, Capacity C_LAnd a threshold circuit 22.
In the VT conversion circuit 21, the node N₁Constant current source I according to the potential of_VTOperates and the capacity C_LCharge. In the threshold circuit 22, the capacitance C_LHas a predetermined threshold value V_THIs exceeded, the output, that is, the output signal 2A is inverted.
As a result, the electric charge becomes an empty capacitance C_LTo the node N₁After a lapse of time corresponding to the potential of the output signal 2A, the output signal 2A is inverted. At the time of the sensing operation for detecting the surface shape of the detection target, by measuring this time length, the unevenness of the skin surface can be known.
[0015]
At the time of a calibration operation for adjusting the detection sensitivity of the sensor circuit 2, the time signal comparison circuit 33 operates based on the calibration signal CAL from the calibration control circuit 40, and calibration by the calibration circuit 3 is performed. . At this time, the count data of the counter circuit 32 is set to an initial set value in advance so that all the load elements are deactivated. The output signal 2A from the VT conversion circuit 21 is set to an initial set value at the start of each detection operation. Then, a reference pulse signal 3A having a pulse width corresponding to a desired detection sensitivity is supplied to the sensor cell 11, and the detection operation is sequentially performed by the sensor cell 11 in synchronization with the reference pulse signal 3A.
As a result, an output signal 2A is obtained from the sensor circuit 2, and as shown in FIG. 15, the time signal comparison circuit 33 compares the output signal 2A with the reference pulse signal 3A. For example, the output signal 2A and the reference pulse signal 3A The counter input signal 3B is generated by the logical product of
[0016]
The output signal 2A has a capacitance C_fIs constant, the delay time ts from the rising edge of the reference pulse signal 3A to the rising edge of the output signal 2A changes according to the load of the load circuit 31.
Therefore, when the output signal 2A changes earlier than the time determined by tr (ts <tr) (time T11, T12), the counter input signal 3B is input to the counter circuit 32 for each detection operation. At 32, the count data is incremented, and the load of the load circuit 31 increases sequentially.
[0017]
When the output signal 2A changes after the time determined by tr (ts ≧ tr) (time T13), the detection sensitivity of the sensor circuit 2 becomes a desired sensitivity corresponding to tr, and the counter input signal 3B becomes The output is stopped, and the selected state of the load element at that time is held by the counter circuit 32.
Therefore, for example, Z_k= Z · 2^k-1By setting (k is a natural number), the value of the load circuit 31 increases by Z each time the count data is counted up, and the detection sensitivity can be adjusted in Z units.
Such a calibration operation is individually performed for each sensor cell 11 and is adjusted to an appropriate detection sensitivity. Even if the characteristic of the sensor circuit 2, that is, the detection sensitivity is different for each sensor cell due to process variation, each calibration operation is performed. The detection performance of the sensor cells can be made uniform.
[0018]
[Problems to be solved by the invention]
However, in such a conventional surface shape recognition sensor device, when adjusting characteristics of a sensor circuit provided in each sensor cell, a calibration control circuit is provided to select a desired sensor cell. There is a problem that the circuit size of the surface shape recognition sensor device is increased. In particular, since the above-mentioned calibration control system is further added to the control system for controlling the normal surface shape detection operation, the circuit configuration and control become complicated, resulting in an increase in chip area and manufacturing yield. In addition, there is a problem that the manufacturing cost increases as a whole due to a reduction in the design time and an increase in the design time.
The present invention has been made to solve such a problem, and has as its object to provide a surface shape recognition sensor device capable of calibrating the detection sensitivity of each sensor cell with a small circuit configuration.
[0019]
[Means for Solving the Problems]
In order to achieve such an object, a surface shape recognition sensor device according to the present invention includes a detection element that detects an amount of electricity that changes according to the surface shape of a detection target, and a quantity of electricity detected by the detection element. A sensor circuit having a sensor circuit for performing a sensing operation of measuring and converting the output into an output signal corresponding to the quantity of electricity, and arranging the sensor cells two-dimensionally, selecting one of these sensor cells in order by a decoder, and selecting the selected sensor cell A surface shape recognition sensor device for detecting unevenness of the surface shape based on the sensor output obtained from the sensor cell, and as a decoder, these sensor cells based on an address signal output from a control circuit for controlling the surface shape recognition sensor device. And a decoder for sequentially selecting one of the sensor cells. At the same time supplies the calibration signal line calibration signals output from the control circuit to indicate ShonAnd a plurality of word lines commonly connected to a plurality of sensor cells selected at the same time among the sensor cells.WithA block selection for controlling a decoder to divide each word line into a predetermined number of blocks and outputting a block selection signal for selecting one of the blocks based on an address signal for selecting one of the word lines Block multiplexing for selecting a sensor cell to be calibrated by simultaneously selecting all word lines belonging to the block based on a logical product of a circuit, a block selection signal, and a multiple selection control signal supplied at the time of calibration And a selection circuit,Each sensor cell is provided with a calibration circuit that adjusts the detection sensitivity of the sensor circuit based on a sensor output obtained by a sensing operation in the sensor circuit of the sensor cell, and a calibration signal is supplied from a calibration signal line. In addition, when selected by the decoder, a calibration operation for adjusting the detection sensitivity of the sensor circuit using the calibration circuit is performed.
[0022]
In this case, each block may be provided with the same number of word lines as the number of sensing operations for adjusting the detection sensitivity performed by each sensor cell during calibration.
Alternatively, each block is provided with one more word line than the number of sensing operations for adjusting the detection sensitivity performed by each sensor cell at the time of calibration, and the block multiplexing selection circuit uses the block selection signal from the block selection circuit and the calibration. All word lines other than the word line corresponding to the address signal are simultaneously selected among the word lines belonging to the block selected by the block selection signal, based on the logical product with the multiple selection control signal supplied at that time. Thus, a cell to be calibrated may be selected. At this time, a gate circuit which is provided for each word line and outputs an exclusive OR of a word line selection signal instructing selection of the word line based on an address signal and a multiple selection control signal is provided as a block multiple selection circuit. May be used.
[0023]
Further, another surface shape recognition sensor device according to the present invention includes a detection element that detects an amount of electricity that changes in accordance with the surface shape of a detection target, and an amount of electricity detected by the detection element, and measures the amount of electricity. A sensor cell having a sensor circuit that performs a sensing operation of converting to a corresponding output signal and outputting the signal is arranged two-dimensionally, and one of these sensor cells is sequentially selected by a decoder, and is sequentially obtained from the selected sensor cell. A surface shape recognition sensor device that detects unevenness of a surface shape based on a sensor output, and sequentially selects one of these sensor cells as a decoder based on an address signal output from a control circuit that controls the surface shape recognition sensor device. And a decoder connected to each of the sensor cells, and instructs calibration for each of the sensor cells. A calibration signal line for supplying calibration signals simultaneously output from the control circuit,A plurality of word lines commonly connected to a plurality of sensor cells selected at the same time among the sensor cells, a decoder is provided with a collective multiplex selection circuit, and based on a multiplex selection control signal supplied at the time of calibration. Select all sensor cells to be calibrated by selecting all word lines simultaneouslyEach sensor cell is provided with a calibration circuit that adjusts the detection sensitivity of the sensor circuit based on a sensor output obtained by a sensing operation in the sensor circuit of the sensor cell, and a calibration signal is supplied from a calibration signal line. And when selected by the decoder, a calibration operation for adjusting the detection sensitivity of the sensor circuit using the calibration circuit is performed.
[0024]
At this time, a word line selection signal and a multiple selection control signal, which are provided as a collective multiple selection circuit for each word line and instruct the selection of the word line based on an address signal for selecting one of the word lines, are provided. May be used.
Further, the decoder is provided with a word line selection circuit for each word line, and an address signal for selecting one of the word lines and a non-selection control supplied when all the word lines are deselected. The logical product with the signal may be output to the gate circuit as a word line selection signal.
[0025]
Further, another surface shape recognition sensor device according to the present invention includes a detection element that detects an amount of electricity that changes in accordance with the surface shape of a detection target, and an amount of electricity detected by the detection element, and measures the amount of electricity. A sensor cell having a sensor circuit that performs a sensing operation of converting to a corresponding output signal and outputting the signal is arranged two-dimensionally, and one of these sensor cells is sequentially selected by a decoder, and is sequentially obtained from the selected sensor cell. A surface shape recognition sensor device that detects unevenness of a surface shape based on a sensor output, and sequentially selects one of these sensor cells as a decoder based on an address signal output from a control circuit that controls the surface shape recognition sensor device. And a decoder connected to each of the sensor cells, and instructs calibration for each of the sensor cells. A calibration signal line for simultaneously supplying a calibration signal output from the control circuit, and a plurality of word lines commonly connected to a plurality of sensor cells selected simultaneously among the sensor cells. A selection circuit is provided to control each word line by dividing it into blocks by a predetermined number, and to output a block selection signal for selecting one of the blocks based on an address signal for selecting one of the word lines. A cell to be calibrated is selected by providing a word line selection circuit and selecting one of the word lines based on the logical product of the block selection signal and the address signal.A batch selection address output circuit is provided to output a batch selection address for selecting all word lines at the same time, instead of an address signal for selecting one of the word lines.Each sensor cell is provided with a calibration circuit that adjusts the detection sensitivity of the sensor circuit based on a sensor output obtained by a sensing operation in the sensor circuit of the sensor cell, and a calibration signal is supplied from a calibration signal line. And when selected by the decoder, a calibration operation for adjusting the detection sensitivity of the sensor circuit using the calibration circuit is performed.
[0026]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a configuration of a surface shape recognition sensor device according to an embodiment of the present invention. The same or equivalent parts as those in the surface shape recognition sensor device of FIG. .
In this surface shape recognition sensor device, the sensor cells 11 are arranged in a two-dimensional matrix of p rows × q columns, and each of the sensor cells 11 includes word lines WL1 to WLp for selectively controlling the sensor cells 11 and the sensor cells 11 11 are connected in a grid pattern to the data lines DL1 to DLq that propagate the output of the eleventh output.
[0027]
A decoder 20 and an A / D conversion circuit 30 are provided around these sensor cells 11. The decoder 20 controls the word lines WL1 to WLp according to the input address signal ADR. The A / D conversion circuit 30 converts an analog signal input from the data lines DL1 to DLq into a digital output signal 30A and outputs the digital output signal 30A. Each sensor cell 11 is commonly connected to the same calibration signal line CL, and the same calibration signal CAL is simultaneously supplied to each sensor cell 11 via the calibration signal line CL during calibration.
[0028]
In the present invention, the calibration signal CAL instructs each sensor cell 11 to perform a normal surface shape detection operation or a calibration operation, and uses a normal calibration control circuit (see FIG. 11) as described above without using the calibration control circuit (see FIG. 11). The sensor cell 11 to be calibrated is selected by the decoder 20 used in the surface shape detection operation.
Note that these address signals ADR (further, ADB and ADW to be described later) and calibration signals CAL are supplied from a control circuit 50 which is a host device such as a CPU for externally controlling the surface shape recognition sensor device. The information may be separately generated and supplied inside the shape recognition sensor device 10.
[0029]
As shown in FIG. 2, the sensor cell 11 has substantially the same configuration as the above-described conventional sensor cell (see FIG. 12), and the same or equivalent parts are denoted by the same reference numerals.
In a conventional sensor cell, the calibration signal CAL is input to the selection circuit 4 to control the operation of the sensor cell itself, and has a redundant configuration.
In the sensor cell 11 of the present invention, only the word line WL is input to the selection circuit 4, and the calibration signal CAL is input only to the time signal comparison circuit 33.
[0030]
Next, a surface shape recognition sensor device according to the first embodiment of the present invention will be described with reference to FIGS. FIG. 3 is a block diagram showing the decoder 20 used in the surface shape recognition sensor device according to the first embodiment. FIG. 4 is a timing chart showing the operation of the decoder of FIG.
In this decoder 20, the word line WL is set to 2^mOne block is configured for each book (m is an integer of 2 or more), and is managed as blocks 101, 102, 103,. Each block has a gate 110 that decodes an address value corresponding to the word line WL in a word line selection address signal ADW (m bits) and outputs a word line selection signal for activating the word line. A buffer 111 for activating the word line WL in response to a word line selection signal from the gate 110 is provided for each word line WL.
[0031]
Also, for each block, a gate 120 (block selection circuit) for decoding an address value corresponding to the block out of the block selection address signal ADB, and an output of the gate 120 to each gate 110 of the block A buffer 121 is provided for supplying as a block selection signal SB (SB1, SB2, SB3,...).
When any of the address signals ADB and ADW is supplied to the decoder 20, the block selection signal SB is output to any of the blocks according to the address value of the address signal ADB. One of the word lines WL is activated by an output of the gate 110 corresponding to the address value of the address signal ADW.
[0032]
More specifically, complementary signals (m bits / 2m) indicating positive logic and negative logic for each address bit are used as these address signals ADB and ADW. Therefore, a positive logic or negative logic address bit which becomes High level corresponding to the address of the word line WL is selectively input to each gate 110, and its logical product is output as a word line selection signal. You. The same applies to each of the gates 120. Each address bit having a High level corresponding to the address of the block is selectively input, and its logical product is output as a block selection signal.
[0033]
In such a configuration, at the time of calibration, the calibration signal CAL is supplied to all the sensor cells 11 (in FIG. 4, described as High level), and the address signals ADB, ADB, ADW is sequentially changed to select each word line in order. As a result, for example, as shown in FIG. 4, the block selection signal SB1 of the block 101 becomes High level, and the word lines WL1 to WL2^mAre sequentially activated one by one. Subsequently, the block selection signal SB2 of the block 102 becomes valid, and the word line WL2^m+1 to WL2^{m + 1}Are sequentially activated one by one.
[0034]
Thereafter, all the word lines WL1 to WLp are selected one by one, and after one cycle is completed, the process returns to the word line WL1 and the address signals ADB and ADW are sequentially changed to select each word line in order.
In this way, if the above cycle is repeatedly executed by the number of adjustment stages of calibration, the calibration operation of the number of adjustment stages is performed for each sensor cell 11.
Note that the calibration operation in each sensor cell 11 is the same as in FIGS. 14 and 15 described above, and a description thereof will be omitted.
[0035]
As described above, the calibration signal line CL to which the sensor cells 11 are connected in common is provided, and a calibration signal for instructing calibration is supplied to each sensor cell via the calibration signal line (in FIG. 4, , High level), in each sensor cell 11, when the calibration signal CAL is supplied from the calibration signal line CL and selected by the decoder 20, the detection sensitivity of the sensor circuit 2 using the calibration circuit 3 Is performed, calibration can be performed using a decoder used for normal sensing without adding a calibration control circuit, and an increase in circuit scale can be reduced.
[0036]
Next, a surface shape recognition sensor device according to a second embodiment of the present invention will be described with reference to FIGS. FIG. 5 is a block diagram showing a decoder 20A used in the surface shape recognition sensor device according to the second embodiment. FIG. 6 is a timing chart showing the operation of the decoder of FIG.
In the first embodiment, a case has been described in which each word line WL is selected one by one in the same manner as in the normal surface shape detection operation at the time of calibration. In this embodiment, a case where a plurality of word lines are simultaneously selected in a block unit will be described.
[0037]
Compared to the decoder 20 of the first embodiment (see FIG. 3), the decoder 20A of the present embodiment has a block selection signal SB and a multiple selection control signal SS for each block as shown in FIG. Is provided as a block multiple selection control signal SSx (SS1, SS2, SS3,...). In addition, each block is provided with a block multiplex selection circuit 113 including a gate 112 disposed between the gate 110 of each word line WL and the buffer 111. The output of the gate 110 of the word line WL and the block multiple selection control signal SSx of the block are input to each gate 112, and an exclusive OR (EOR) of these inputs is output to the buffer 111.
[0038]
In the decoder 20A, at the time of the normal surface shape detection operation, the block multi-selection control signal SSx from the gate 122 of each block is set to the Low level in order to set the multi-selection control signal SS to the Low level. 112 operates as a buffer. As a result, only one word line WL corresponding to the address signals ADB and ADW is activated.
The multiple selection control signal SS and the address signals ADB and ADW are supplied from a control circuit 50 which is a host device such as a CPU for externally controlling the surface shape recognition sensor device. It may be generated and supplied separately inside.
[0039]
On the other hand, at the time of calibration, by setting the multiple selection control signal SS to the high level, the block multiple selection control signal SSx becomes the high level only in the block selected by the address signal ADB.
Therefore, at the time of calibration, the calibration signal CAL is supplied to all the sensor cells 11 (in FIG. 6, described as High level), and the word lines are sequentially selected by sequentially changing the address signals ADB and ADW. In this case, for example, as shown in FIG. 6, the block selection signal SB1 of the block 101 becomes High level, and the word lines WL1 to WL2ⁿAre sequentially selected. Note that n is the number of load elements Z of the calibration circuit 3.
[0040]
At this time, since the block multiple selection control signal SS1 is input from the gate 122 to each gate 112 of the block 101 and each gate 112 operates as an inverter, the word lines WL1 to WL2 of the block 101ⁿAmong them, all the word lines other than one word line WL corresponding to the address value of the address ADW become active.
In other words, with one address value of the address signal ADW, 2ⁿ-1 word line is multiplexed and selected, so that the address value of the address signal ADW is simply cycled, ie, 2ⁿIn each cycle, each word line WL of the block is 2ⁿIt becomes active once.
[0041]
In this way, by performing the above-described selection operation for each block, calibration operations for the number of adjustment stages are performed for each sensor cell 11.
Thus, by supplying the address signal in the same manner as in the normal surface shape detection operation, the calibration can be completed for all the sensor cells 11, and compared with the first embodiment, the calibration is completed.ⁿCalibration can be performed at a speed of -1 times, and the time required for calibration can be greatly reduced.
[0042]
In this embodiment, each word line WL belonging to the block is selected by the block multi-selection circuit 113 based on the logical product of the block selection signal SB of the block and the multi-selection control signal SS supplied during calibration. Although the case where all the word lines other than the word line corresponding to the address signal ADW are selected at the same time has been described as an example, the present invention is not limited to this. For example, when the multiple selection control signal SS is supplied by the block multiple selection circuit 113, all the word lines WL of the block selected by the address signal ADB may be activated. Thus, the time required for calibration can be greatly reduced. At this time, by dividing each block so as to have the same number of word lines as the number of adjustment stages, that is, the number of times of the calibration operation, calibration can be performed efficiently.
[0043]
Next, a surface shape recognition sensor device according to a third embodiment of the present invention will be described with reference to FIGS. FIG. 7 is a block diagram showing a decoder 20B used in the surface shape recognition sensor device according to the third embodiment. FIG. 8 is a timing chart showing the operation of the decoder of FIG.
In the second embodiment, a case has been described in which a plurality of word lines WL are multiple-selected in block units during calibration. In the present embodiment, a case will be described in which all word lines are selected at the same time, not in block units.
[0044]
Compared to the decoder 20 of the first embodiment (see FIG. 3), each block of the decoder 20B of the present embodiment has a gate 110 and a buffer 111 of each word line WL, as shown in FIG. A batch multiplexing selection circuit 115 including a gate 114 disposed between them is provided. The output of the gate 110 of the word line WL and the multiple selection control signal SS are input to each gate 114, and the logical sum (OR) of these inputs is output to the buffer 111. In addition, one of the inputs of each gate 110 includes a non-selection control signal SI output from the control circuit 50 during the calibration operation (ie, when the calibration signal CAL in FIG. 8 is supplied to each sensor cell). (Negative logic) is supplied.
[0045]
In the decoder 20B, during a normal surface shape detection operation, the gate 110 operates as an AND gate by setting the non-selection control signal SI to a high level. By setting the multiple selection control signal SS to a low level, the gate 114 of each block operates as a buffer. As a result, only one word line WL corresponding to the address signals ADB and ADW is activated.
The non-selection control signal SI is supplied from the control circuit 50 which is a higher-level device such as a CPU for externally controlling the surface shape recognition sensor device, but is separately generated and supplied inside the surface shape recognition sensor device. You may make it.
[0046]
On the other hand, at the time of calibration, by setting the non-selection control signal SI to Low level, the output of each gate 110 becomes Low level, so that the state of all word lines WL can be controlled according to the multiple selection control signal SS.
That is, when the multiple selection control signal SS is at a high level, all the word lines WL are in an active state, and when they are at a low level, all the word lines WL are in an inactive state.
[0047]
Therefore, at the time of calibration, for example, as shown in FIG. 8, the non-selection control signal SI is set to Low level, and the calibration signal CAL is supplied to all the sensor cells 11.
Then, the number of cycles 2 for the number of adjustment stages of the calibrationⁿThe sensing operation may be performed in all the sensor cells 11 by setting the multiple selection control signal SS to the High level only during the period of −1. At this time, the address signals ADB and ADW may have any address values.
[0048]
Thereby, the calibration can be completed for all the sensor cells 11, and the calibration can be performed at a speed p times (p is the number of word lines WL) as compared with the first embodiment. The time required for calibration can be greatly reduced.
When the decoder 20 manages each word line WL for each of a plurality of blocks, (2ⁿ-1) Since ≪p, it is possible to further reduce the calibration time and simplify the control as compared with the second embodiment.
[0049]
Next, a surface shape recognition sensor device according to a fourth embodiment of the present invention will be described with reference to FIG. FIG. 9 is a block diagram showing a decoder 20C used in the surface shape recognition sensor device according to the fourth embodiment.
In the third embodiment, a case has been described in which the block multiple selection circuit 115 is provided in each block, and the multiple selection control signal SS is output during calibration, so that all the word lines WL are multiple-selected. In the present embodiment, instead of providing the block multiplex selection circuit 115 in each block, all words are output using a block selection address output circuit that outputs a block selection address value as address signals ADB and ADW supplied to each block. A case where lines are selected simultaneously will be described.
[0050]
Compared with the decoder 20 of the first embodiment (see FIG. 3), the decoder 20C of the present embodiment includes an address gate circuit 130 and a batch selection address output circuit 140 as shown in FIG. Have been. The address gate circuit 130 includes gates 131 provided for each address signal line. The gates 131 output a logical product (AND) of the address value and the non-selection control signal SI (negative logic). The batch selection address output circuit 140 includes gates 141 provided for each address signal line, and the logical sum (OR) of the output of the gate 131 and the multiple selection control signal SS from these gates 141 is used as an address for each block. The signals are output as signals ADB and ADW.
[0051]
In the decoder 20C, during a normal surface shape detection operation, the gate 131 operates as a buffer by setting the non-selection control signal SI to a high level. The gate 141 also operates as a buffer by setting the multiple selection control signal SS to Low level.
Thus, the address signals ADB and ADW are supplied to each block as they are, so that only one word line WL corresponding to these address values is activated.
The non-selection control signal SI and the multiple selection control signal SS are supplied from a control circuit 50 which is a host device such as a CPU for externally controlling the surface shape recognition sensor device. May be separately generated and supplied.
[0052]
On the other hand, at the time of calibration, by setting the non-selection control signal SI to Low level, the output of each gate 131 becomes Low level, so that an address value corresponding to the level of the multiple selection control signal SS is supplied to each block. .
At this time, by setting in advance a value at which all the address lines are at the High level as a collective selection address value for selecting all the word lines WL, it is only necessary to set the multiple selection control signal SS to the High level. The collective selection address value is supplied from each gate 131 to the gates 110 and 120 of each block. As a result, all the word lines WL are activated as in the case of FIG.
[0053]
As described above, complementary signals are used as the address signals ADB and ADW, and a positive logic or negative logic address bit which becomes a High level at the address to be decoded is selectively applied to each of the gates 110 and 120. Has been entered. Therefore, by outputting from the collective select address output circuit 140 a collective select address value in which all the address lines go high in response to the multiple select control signal SS, all the word lines are activated.
When the multiple selection control signal SS is at a low level, the output of the address gate circuit 130 is output as address signals ADB and ADW. At this time, by setting the non-selection control signal SI to Low level, all the address lines are set to Low level, and no word line WL is selected.
[0054]
As described above, the batch selection address output circuit 140 is provided, and at the time of calibration, by outputting the batch selection address value as the address signals ADB and ADW supplied to each block, all the word lines are simultaneously selected. Therefore, as in the third embodiment, the calibration can be performed at a speed p times (p is the number of word lines WL) compared to the first embodiment, and the calibration is required. Time can be greatly reduced. Further, it is not necessary to provide the collective multiplex selection circuit 115 in each block as in the third embodiment, and the circuit configuration can be further reduced.
[0055]
【The invention's effect】
As described above, the present invention provides a calibration signal line to which each sensor cell is connected in common, and supplies a calibration signal for instructing calibration to each sensor cell via this calibration signal line. In each sensor cell, a calibration signal is supplied from a calibration signal line.When the decoder selects the word line of the sensor cell by the operation of selecting all or a plurality of word lines at the same time in the block selected by the sensing operation or the operation of selecting all the word lines at the same time by the decoder,When selected, a calibration operation is performed to adjust the detection sensitivity of the sensor circuit using the calibration circuit, so that it is used for normal sensing without adding a calibration control circuit as in the related art. Calibration can be performed using a decoder, and an increase in circuit size can be reduced. In addition, the control operation may be performed by changing the state of the calibration signal and performing exactly the same operation as the normal surface shape detection operation, thereby simplifying the control.

[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a surface shape recognition sensor device according to an embodiment of the present invention.
FIG. 2 is a block diagram showing a sensor cell according to one embodiment of the present invention.
FIG. 3 is a block diagram showing a decoder used in the surface shape recognition sensor device according to the first embodiment of the present invention.
FIG. 4 is a timing chart showing the operation of the decoder of FIG.
FIG. 5 is a block diagram showing a decoder used in the surface shape recognition sensor device according to the second embodiment of the present invention.
FIG. 6 is a timing chart showing the operation of the decoder of FIG.
FIG. 7 is a block diagram showing a decoder used in a surface shape recognition sensor device according to a third embodiment of the present invention.
8 is a timing chart showing the operation of the decoder of FIG.
FIG. 9 is a block diagram showing a decoder used in a surface shape recognition sensor device according to a fourth embodiment of the present invention.
FIG. 10 is an explanatory diagram showing a use state of a general surface shape recognition sensor device.
FIG. 11 is an overall configuration diagram of a conventional surface shape recognition sensor device.
FIG. 12 is a block diagram showing a conventional sensor cell.
FIG. 13 is an implementation example of a load element that can be controlled between an active state and an inactive state.
FIG. 14 is a timing chart showing a detection operation of a sensor cell.
FIG. 15 is a timing chart showing a calibration operation in a sensor cell.
[Explanation of symbols]
Reference Signs List 10: Surface shape recognition sensor device, 11: Sensor cell, 12: Sensor surface, 13: Finger, 14: Finger surface, 15: Passivation film, 16: Insulating layer, 20, 20A, 20B, 20C: Decoder, 30: A / D conversion circuit, 30A digital output signal, 1 detection element, 1A electric quantity, 1B sensor electrode, 2 sensor circuit, 21 voltage-time conversion circuit (VT conversion circuit), 22 threshold circuit, 2A output signal, 3 calibration circuit, 31 load circuit, 32 counter circuit, 33 time signal comparison circuit, 3A reference pulse signal, 3B counter input signal, 4 selection circuit, 101, 102, 103 ... Block, 110 ... Gate (AND), 111, 121 ... Buffer, 112 ... Gate (EOR), 113 ... Block multiplex selection circuit, 114 ... Gate (OR) 115: batch multiplex selection circuit, 120: gate (AND), 122: gate (AND), 130: address gate circuit, 131: gate (AND), 140: batch selection address output circuit, 141: gate (OR), WL , WL1 to WLp: cell selection line, DL, DL1 to DLq: data line, CL: calibration signal line, CAL: calibration signal, ADB: address signal (block selection), ADW: address signal (word line selection), SB1, SB2, SB3: block selection signal, SS: multiple selection control signal, SS1, SS2, SS3: block multiple selection control signal, SI: non-selection control signal, Z₁~ Z_N... Load element, V_DD... Power supply voltage, C_f... Detection capacity, C_p0... parasitic capacitance, C_L... Capacity, R_a... resistance, I, I_VT... current source, Q₁... Pch MOSFET, Q₂... NchMOSFET, RE, / PRE ... sensor circuit control signal, N₁, N₂…node.

Claims (8)

A detecting element that detects an electric quantity that changes according to the surface shape of a detection target, and a sensor that performs a sensing operation that measures the electric quantity detected by the detecting element, converts the electric quantity into an output signal corresponding to the electric quantity, and outputs the output signal. And a sensor cell having a circuit is two-dimensionally arranged, one of these sensor cells is sequentially selected by a decoder, and surface shape recognition for detecting irregularities of the surface shape based on sensor outputs sequentially obtained from the selected sensor cell. A sensor device,
The decoder includes a decoder that sequentially selects any of these sensor cells based on an address signal output from a control circuit that controls the surface shape recognition sensor device,
A calibration signal line that is connected in common to the sensor cells and simultaneously supplies a calibration signal output from the control circuit to instruct calibration for each sensor cell ,
A plurality of word lines commonly connected to a plurality of sensor cells selected simultaneously among the sensor cells ,
The decoder controls the word lines by dividing the word lines into blocks by a predetermined number, and outputs a block selection signal for selecting one of the blocks based on an address signal for selecting one of the word lines. Block selecting circuit, and simultaneously selecting all the word lines belonging to the block based on the logical product of the block selecting signal and the multiple selection control signal supplied at the time of calibration, thereby selecting the sensor cells to be calibrated. A block multiplex selection circuit for selecting
Each of the sensor cells has a calibration circuit that adjusts the detection sensitivity of the sensor circuit based on a sensor output obtained by a sensing operation in the sensor circuit of the sensor cell, and a calibration signal is supplied from the calibration signal line. And performing a calibration operation for adjusting the detection sensitivity of the sensor circuit by using the calibration circuit when selected by the decoder. The surface shape recognition sensor device according to claim 1,
The surface shape recognition sensor device , wherein each block has the same number of word lines as the number of sensing operations for adjusting the detection sensitivity performed in each sensor cell during calibration . The surface shape recognition sensor device according to claim 1,
Each of the blocks has one more word line than the number of sensing operations for adjusting the detection sensitivity performed by each sensor cell during calibration,
Each of the word lines belonging to the block selected by the block selection signal is based on a logical product of a block selection signal from the block selection circuit and a multiple selection control signal supplied at the time of calibration. Wherein a cell to be calibrated is selected by simultaneously selecting all word lines other than the word line corresponding to the address signal . The surface shape recognition sensor device according to claim 3,
The block multiple selection circuit is provided for each of the word lines, and outputs an exclusive OR of a word line selection signal instructing selection of the word line based on the address signal and the multiple selection control signal. It is made of the surface shape recognition sensor device characterized by. A detecting element that detects an electric quantity that changes according to the surface shape of a detection target, and a sensor that performs a sensing operation that measures the electric quantity detected by the detecting element, converts the electric quantity into an output signal corresponding to the electric quantity, and outputs the output signal. And a sensor cell having a circuit is two-dimensionally arranged, one of these sensor cells is sequentially selected by a decoder, and surface shape recognition for detecting irregularities of the surface shape based on sensor outputs sequentially obtained from the selected sensor cell. A sensor device,
The decoder includes a decoder that sequentially selects any of these sensor cells based on an address signal output from a control circuit that controls the surface shape recognition sensor device,
A calibration signal line that is connected in common to the sensor cells and simultaneously supplies a calibration signal output from the control circuit to instruct calibration for each sensor cell,
A plurality of word lines commonly connected to a plurality of sensor cells selected simultaneously among the sensor cells,
The decoder has a batch multiple selection circuit that selects all sensor cells to be calibrated by simultaneously selecting all word lines based on a multiple selection control signal supplied at the time of calibration,
Each of the sensor cells has a calibration circuit that adjusts the detection sensitivity of the sensor circuit based on a sensor output obtained by a sensing operation in the sensor circuit of the sensor cell, and a calibration signal is supplied from the calibration signal line. And performing a calibration operation for adjusting the detection sensitivity of the sensor circuit by using the calibration circuit when selected by the decoder . The surface shape recognition sensor device according to claim 5,
The batch multiplex selection circuit is provided for each of the word lines, and based on an address signal for selecting any one of the word lines, a word line selection signal for instructing selection of the word line and the multiplex selection control signal. A surface shape recognition sensor device comprising a gate circuit that outputs a logical sum of The surface shape recognition sensor device according to claim 6 ,
The decoder is provided for each word line, and is a logical product of the address signal for selecting one of the word lines and a non-selection control signal supplied when all the word lines are deselected. A word line selection circuit that outputs the word line selection signal to the gate circuit as the word line selection signal . A detecting element that detects an electric quantity that changes according to the surface shape of a detection target, and a sensor that performs a sensing operation that measures the electric quantity detected by the detecting element, converts the electric quantity into an output signal corresponding to the electric quantity, and outputs the output signal. And a sensor cell having a circuit is two-dimensionally arranged, one of these sensor cells is sequentially selected by a decoder, and surface shape recognition for detecting irregularities of the surface shape based on sensor outputs sequentially obtained from the selected sensor cell. A sensor device,
The decoder includes a decoder that sequentially selects any of these sensor cells based on an address signal output from a control circuit that controls the surface shape recognition sensor device,
A calibration signal line that is connected in common to the sensor cells and simultaneously supplies a calibration signal output from the control circuit to instruct calibration for each sensor cell,
A plurality of word lines commonly connected to a plurality of sensor cells selected simultaneously among the sensor cells,
The decoder controls the word lines by dividing the word lines into blocks by a predetermined number, and outputs a block selection signal for selecting one of the blocks based on an address signal for selecting one of the word lines. A word line selection circuit for selecting a cell to be calibrated by selecting any one word line based on a logical product of the block selection signal and the address signal; A batch selection address output circuit for outputting a batch selection address for simultaneously selecting all word lines, instead of an address signal for selecting any of the word lines,
Each of the sensor cells has a calibration circuit that adjusts the detection sensitivity of the sensor circuit based on a sensor output obtained by a sensing operation in the sensor circuit of the sensor cell, and a calibration signal is supplied from the calibration signal line. And performing a calibration operation for adjusting the detection sensitivity of the sensor circuit by using the calibration circuit when selected by the decoder .

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