JPS634188B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention displays changes in voltage and the like. For example, the present invention relates to a liquid crystal display device used as an analog display device such as a voltmeter.

Conventionally, when measuring data, etc. is displayed step by step using a liquid crystal display device formed in the form of a bar graph, the circuit configuration is generally complicated because a predetermined voltage is applied to each bar graph. It was something like that. That is, the selection of the bar graph and the length to be displayed must all be done on the circuit side.

Therefore, the present invention provides a liquid crystal display device in which display is controlled by changing the area ratio of opposing electrodes of the liquid crystal display device and changing the applied voltage between the electrodes.

An embodiment of the present invention will be described below based on the drawings. In FIG. 1, 1 and 2 indicate common electrodes of the liquid crystal display device, which are arranged opposite to segment electrodes 3-8. Here, the facing surfaces 3a to 8a of the segment electrodes 3 to 8 facing the common electrode 2 are made equal to each other, but the facing surfaces 3b of the segment electrodes 3 to 8 facing the common electrode 1 are equal to each other. The area of 8b is sequentially changed. A variable voltage source 9 is applied between the common electrode 1 and the common electrode 2. Note that the common electrode 2 and the segment electrode 3 are short-circuited and held at the same potential. A liquid crystal is interposed between the common electrodes 1 and 2 and the segment electrodes 3 to 8 to constitute a display device, but such a display device can be easily constructed by a person skilled in the art, and the present invention also covers the same. Since the structure of such a liquid crystal display device is not unique, the description thereof will be omitted.

In the above configuration, the area ratio of each opposing surface shown in the first diagram is 6:14 for opposing surfaces 4b and 4a, and 6:14 for opposing surface 5b.
and 5a at 13:14, opposing surfaces 6b and 6a at 24:14, opposing surfaces 7b and 7a at 40:14, and opposing surfaces 8b and 8a at
61:14, and the response voltage of the liquid crystal is 1.4 volts.
Set the non-response voltage (threshold voltage) to 1.0 volts.

The opposing surfaces 3b...8b and the common electrode 1 shown in the first diagram and the opposing surfaces 4a...8a and the common electrode 2 each constitute a capacitor, and become an equivalent circuit shown in the second diagram.
Here, the capacitors 3B...8B correspond to the opposing surfaces 3b...8b, and the capacitors 4A...8A correspond to the opposing surfaces 4a...8a. If the voltage value of the variable voltage source 9 is v ₀ , the opposing surfaces 4b and 4a
...Since the area ratios of 8b and 8a are as described above, the voltages applied to each of capacitors 4B...8B are 140v ₀ /20, 14v ₀ /27, 14v ₀ /38, 14v ₀ /54,
It becomes 14v ₀ /75. Therefore, FIG. 3 shows the state of the voltage applied to the capacitors 3B...8B when the voltage v ₀ is changed. The response voltage of the liquid crystal is
Since the voltage is 1.4 _volts , the liquid crystals of the capacitors 3B, 4B, . Therefore, the display portions corresponding to the facing surfaces 3b...8b shown in the first diagram are turned on, and a bar graph is sequentially formed. Note that when the voltage v ₀ takes a value other than the value shown in FIG. 3, the bar graph is illuminated by the half-response liquid crystal. For example, voltage v ₀ is 3
In the case of bolts, in FIG. 1, the opposing surfaces 3b,
The bar graphs corresponding to 4b and 5b are lit,
Those corresponding to the facing surface 6b are turned on in a half-response, and those corresponding to the facing surfaces 6b to 8b are not lit.

FIG. 4 shows an embodiment in which the segment electrode is further divided into smaller parts and applied to a voltmeter. 10 and 1
1 is a common electrode, and a part of the common electrode 10 is formed into a step shape. Segment electrodes 12a to 12k are provided opposite common electrodes 10 and 11 corresponding to each step. FIG. 5 shows the measurement voltage applied between terminals a and b and the area ratio of the segment electrodes, where A is the area where the segment electrodes 12a to 12k face the common electrode 10, and B is the area of the common electrode 11.
It shows the area facing . In the same diagram, at each voltage value, the display parts corresponding to the area A of each segment electrode are lit up in sequence. Note that the response and non-response voltages of the liquid crystal are the same as in the previous embodiment.

FIG. 6 shows an example in which the bar graphs have the same length. The common electrode 13 is formed in a rectangular shape, and the common electrode 14 is formed in a step shape. Segment electrode 15
When the opposing areas of a to 15j and the common electrodes 13 and 14 are set as shown in FIG. 7, the lighting area increases according to each voltage value. Note that the response and non-response voltages of the liquid crystal are the same as in the previous embodiment.

FIG. 8 shows an embodiment of the thermometer. Common electrode 16
and 17, segment electrodes 18a to 18g
are arranged. 19 is a thermistor, 20 is a resistor, 21 is a pulse generator, and 22 is a flip-flop circuit.

In the above configuration, using a twisted nematic (TN) liquid crystal with a response voltage of 1.4 volts,
An example of displaying the temperature in 10°C steps from 50°C to -10°C will be explained. Figure 10 shows the area ratio when a thermistor having the resistance characteristic Rt shown in Figure 9 is used, the voltage driven by the output of the flip-flop circuit 22 is 12 volts, and the resistance _R0 is 530KΩ. It is. Here, E is the segment electrodes 18a to 1 facing the common electrode 16.
8g is the opposing area, and F is the opposing area of the segment electrodes 18a to 18g facing the common electrode 17. As is clear from this, for a step temperature of 10 DEG C., the display portions corresponding to the opposing surfaces of the common electrode 16 and the segment electrodes 18a to 18g are lit in sequence. For voltage between steps,
There is a half-response state of the liquid crystal, and by lighting in this half-response, it is possible to grasp the general condition of the inter-step temperature.

Note that when the operating temperature range is wide and the response voltage of the liquid crystal is subject to change, it is necessary to determine the opposing area ratio of the segment electrodes in consideration of the fluctuating response voltage.

FIG. 11 shows an embodiment in which the segment electrodes have a special shape. The segment electrodes facing the common electrode 23 are the same as those in the previously described embodiments, but the segment electrodes 25a to 25a facing the common electrode 24 are
25c has a bent shape. According to this, even if the facing area is large, there is no need to make the segment electrodes long, so the space can be effectively utilized and the degree of freedom in shape is increased.

The above bending shape is not limited to this, and the segment electrodes and the common electrode may have any shape as long as a predetermined opposing area can be obtained between the segment electrodes and the common electrode.

Therefore, as an example, FIGS. 12 to 14 show an example in which electrodes are formed in a circular shape.
This will be explained based on the diagram. FIGS. 12 and 13 only show the arrangement of the electrodes. Reference numeral 26 indicates a plurality of segment electrodes which are insulated from each other and are each composed of opposing surfaces 27a and 27b, opposing surfaces 28a and 28b, . . . opposing surfaces 37a and 37b. The area of the facing surfaces 27b...37b facing the common electrode 43 formed in a circular shape is gradually decreased at a predetermined ratio. Opposing surfaces 27a to 37a
The opposing surfaces 27a to 37a facing the common electrode 38 formed in a circular shape have the same area.

39 is a segment electrode formed in the same manner as the segment electrode 26, and opposing surfaces 40a...40a face the common electrode 41. Just the opposite surface 40b
...40b extends toward the center, and the area facing the common electrode 42 is gradually reduced.
Note that terminals a, b, c, and d are connected to common electrodes 38, 42, 41, and 43, respectively.

In the above configuration, facing surfaces 27a to 37a and 27b are sequentially provided between terminals a and d and between terminals b and c.
~37b and opposing surfaces 40a~40a and 40b~
40b and the response voltage of the liquid crystal and apply a driving voltage, the opposing surfaces 27a to 37
The display sections corresponding to a and 40a...40a are sequentially lit. Fig. 14 shows an example of a display when used as a clock by applying a driving voltage that changes according to a time signal to terminals a to d.The inside shows the hours and the outside shows the minutes. It says 4:15.

In the above-mentioned embodiments, fields of use such as voltmeters, thermometers, and clocks have been shown, but the display is not limited to these, but can be applied to all displays as long as the content to be displayed can be converted into a change in voltage. It can be applied to For example, by using a humidity sensing element to convert humidity into a voltage, and setting the area ratio of the segment electrodes and the common electrode so that the display section lights up in accordance with the change in predetermined step voltage of this voltage, humidity can be adjusted. It can be used as a meter display device.

Furthermore, by using a photoconductive element and converting changes in the amount of light received into voltage changes, it can also be used as a device that displays the degree of brightness, such as an illumination meter or a transparency display device.

In the above embodiments, a variable voltage was used as the drive voltage applied between the common electrodes, but for example, it is possible to keep the voltage value constant and apply a pulse voltage whose effective value is varied by changing the duty ratio. It's okay. In particular, it is preferable to change the effective value and drive with alternating current from the viewpoint of the lifespan of the liquid crystal.

As described in detail above, the present invention arranges a segment electrode facing two common electrodes, changes the mutual area ratio of the opposing surfaces of the common electrode and the opposing segment electrode, and applies a driving voltage between the common electrodes. Since the display is made by changing the display area, the wiring from the drive circuit to the display section only needs to be a lead wire connecting to the common electrode, so that the number of wirings is extremely small. Furthermore, since the information to be displayed only needs to be a drive voltage applied to the common electrode, the circuit configuration is also extremely simple.
Furthermore, it consumes less power, is easy to manufacture, and changes the lighting state depending on the area ratio, so the shape can be set relatively freely, and it can be easily installed in small devices or objects with space constraints. It is.

Furthermore, it is highly versatile because it is possible to easily switch and display measurement values of the same system using one type of display device.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a display device according to an embodiment of the present invention, mainly showing the arrangement of electrodes, FIG. 2 is an equivalent circuit diagram mainly showing its capacitance, and FIG. A voltage characteristic chart for explaining the operation, FIG. 4 is a plan view mainly showing the electrode wiring of another embodiment, FIG. 5 is a chart showing the relationship between the voltage applied to FIG. 4 and the area, and FIG. 7 is a diagram showing the relationship between the applied voltage and area in FIG. 6, and FIG. 8 is a plan view mainly showing the electrode wiring of another embodiment. 9 and 10 are the temperature-voltage characteristic chart of the thermistor shown in FIG. 8 and the relation chart of the opposing area of the electrodes and temperature, respectively, and FIG. FIG. 12 is a plan view mainly showing the electrode arrangement, and FIG. 12 is a plan view mainly showing the electrode arrangement of another embodiment.
Figure 3 is a cross-sectional view taken along the - line shown in Figure 12;
FIG. 14 is an explanatory diagram of the lighting state of the display device shown in FIG. 13. 1...Common electrode, 2...Common electrode, 3-8...
Segment electrode, 21...Pulse generation circuit, 3
7, 38, 50, 51... common electrode, 26-36
...Segment electrode.

Claims (1)

[Claims] 1. A plurality of segment electrodes are arranged to face two common electrodes via a liquid crystal, and the area ratio of the opposing surfaces of each segment electrode facing each common electrode is changed to change the driving voltage applied between the common electrodes. A display device that lights up a display section constituted by one common electrode and a segment electrode facing the common electrode.