JP2960192B2 - Liquid crystal display - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device for continuously changing the brightness of a bar graph display.

[0002]

2. Description of the Related Art As a conventional liquid crystal display device, for example, FIG.
There is something like that shown in In the figure, 1 is a bar graph liquid crystal display in which segments 2 to 8 are arranged in a plurality of bars,
9 is a common electrode of segments 2 to 8, 10 is a drive pulse generator for generating a rectangular drive pulse 11, 12 to 18 are segment electrodes of segments 2 to 8, 19 is a binary number representing a measurement signal 20 input from the outside. The display control unit 21 for converting the data into data has the number of segments 2 to 8 in each segment 2.
Shift register to which the lighting / non-lighting data No. to No. 8 are transferred; 22, a latch circuit for latching the display data 23 transferred to the shift register 21 in accordance with a command from the display control unit 19; If the data is a high level signal, a pulse having a phase opposite to that of the drive pulse 11 is supplied. If the data is a low level signal, the drive pulse 1 is supplied.
This is an exclusive OR circuit that supplies a pulse having the same phase as 1.

Next, the operation will be described. The drive pulse 11 generated by the drive pulse generator 10 is supplied to the common electrodes 9 of the segments 2 to 8 of the bar graph liquid crystal display 1. The measurement signal 20 input from the outside is converted into lighting / non-lighting binary data of each of the segments 2 to 8 by the display control unit 19, and transferred to the latch circuit 22 when the number of segments is transferred to the shift register 21. 2
Latch as 3. If the display data 23 from the latch circuit 22 is a lighting segment, the exclusive OR circuits 24a to 24e apply a pulse a having a phase opposite to that of the drive pulse 11; The pulse b having the same phase as the drive pulse 11 is applied to the segment electrodes 12 to 18 by the logical OR circuits 24f to 24g.
The display is performed by supplying the information to each of them.

[0004]

However, in such a conventional liquid crystal display device, the display driving pulses a and b of the liquid crystal display 1 are in phase or opposite to the driving pulse 11 supplied to the common electrode 9. Since only the binary value of the phase can be selected, only two types of display modes, lighted and non-lighted, can be selected, and there is a problem that the display mode is simple and stale.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and there is no biased electric charge between electrodes which leads to deterioration of a liquid crystal display, so that a new and high-quality display feeling can be obtained. It is an object of the present invention to obtain a liquid crystal display device.

[0006]

A liquid crystal display device according to the present invention has a driving circuit for outputting a high-level or low-level signal from a plurality of output terminals, and a segment connected to each of the driving circuits. , A segment common signal generating circuit that outputs a pulse whose amplitude can be varied, and an output terminal of the drive circuit is connected via a first resistor 26, and each of the output terminals is The second resistor 2 is connected to the segment common signal generation circuit.
7 and a voltage synthesizing circuit to which a pulse from the segment common signal generating circuit and a pulse from the driving circuit are supplied.

[0007]

In the liquid crystal display device according to the present invention, a first resistor is mutually connected to the divided segment electrodes of the liquid crystal display, and a second resistor is commonly connected to each segment electrode. In addition to the static drive pulse, a high-impedance drive pulse is supplied, and a segment common pulse is supplied from the segment common signal generation circuit to each commonly connected segment electrode so that the voltage level width can be controlled arbitrarily. .

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention.
In FIG. 1, the same or equivalent components as those in FIG. 5 are denoted by the same reference numerals, and redundant description will be omitted. First, the configuration will be described. In the figure, reference numerals 25a to 25f denote exclusive OR circuits 2
The gate circuits 25a to 25f and the exclusive OR circuits 24a to 24g constitute a drive circuit. Reference numeral 26 denotes a first resistor for connecting the segment electrodes 12 to 18 to each other,
This first resistor 26 divides the drive pulse to the segment electrode. Reference numeral 27 denotes a second resistor for commonly connecting the segment electrodes 12 to 18. The second resistor 27 divides a driving pulse from a later-described segment common signal generation circuit.
Then, the first resistor 26 and the second resistor 27 constitute a voltage combining circuit. 28 is each segment electrode 12-1
8 is a segment common signal line to which 8 is commonly connected, and 29 is a segment common signal generation circuit for supplying a drive pulse to the segment signal line 28.

Next, the operation will be described. The measurement signal 20 input from the outside is converted into lighting / non-lighting binary data of each of the segments 2 to 8 by the display control unit 19.
Now, the external measurement signal 2 is applied to the segment 6 of the liquid crystal display 1.
When “0” is input, for example, the display control unit 19 inputs binary display data 23 such that the segments 3 to 6 become “1” and the other segments 2 become “0”, and is shifted. The display data 23 is sequentially sent one bit at a time to the register 21, and is latched by the latch circuit 22 when the display data 23 is transferred by the number of segments of the liquid crystal display 1. On the other hand, a data signal of "0" is input from the latch circuit 22 to the exclusive OR circuit 24f corresponding to the segment electrode 17 of the segment 7, and the output of the exclusive OR circuit 24f is generated from the drive pulse generator 10. It becomes a signal having the same phase as the driving pulse 11 and is input to the signal gate circuit 25f. Also, as shown in FIG.
When the data signal “0” of the upper segment is input to the control terminal of the, a signal having the same phase as the drive pulse 11 is supplied to the segment electrode 17, and the display of the segment 7 is turned off. Similarly, the segments for which the display data 23 is “0” are not lit. On the other hand, the outputs of the exclusive OR circuits 24b, 24c, 24d, and 24e corresponding to the segments 3 to 6 in which the display data 23 is "1" are signals having a phase opposite to that of the drive pulse 11, and the signals are gated. The signals are input to the circuits 25b, 25c, 25d, and 25e.
Here, since the data signal of the upper segment is input to each control terminal of the gate circuits 25a to 25f, the gate circuit 25e corresponding to the uppermost segment 6 among the segments whose display data is "1". Is "0" only at the control terminal of
A signal having a phase opposite to 1 is supplied, and the display of the segment 6 is turned on. For the other segments 2, 3, 4, and 5, "1" is input to the control terminals of the gate circuits 25b, 25c, and 25d. The exclusive OR circuit 24
The signals from b, 24c and 24d are electrically cut off.
The segment electrodes 1, 14, 15, which are electrically cut off, are divided into the segment electrodes 1 through the first resistor 26.
6 and the drive pulse (FIG. 2f) generated by the segment common signal generation circuit 29 divided by the second resistor 27 and supplied as drive pulses c, d, and e.

Here, the driving pulses c, d, and e will be described. Assuming that the second resistor 27 connected to the segment common signal line 28 does not have a drive pulse (FIG. 2f), which is a segment common pulse, the drive pulses c, d, and e.
Are connected to the segment electrodes 12 to 16 by the first resistors 26 connected to each other.
As shown in FIG. 2, the voltage divided by the first resistor 26 around the voltage level of １ ／ of the voltage peak value V _LC of the drive pulse 11 as shown in FIG. It will only be a police box. Therefore, the effective voltage value supplied to the segments 2 to 6 is as shown by the broken line in FIG. However, since the relationship between the effective voltage and the transmittance of the liquid crystal display 1 is not generally a linear relationship as shown in FIG. 4, the display of the segments 2 to 6 naturally does not become a linear gradation display. I will. Therefore, the same second resistor 27 is connected to each of the segment electrodes 12 to 18, and a segment common pulse obtained by dividing the in-phase / negative-phase pulse of the drive pulse 11 by a variable resistor into the segment common signal line 28 (see FIG. By supplying 2f), the effective voltage value supplied to the segments 2 to 6 becomes as shown by the solid line in FIG. 3, and the second resistor according to the effective voltage-transmittance characteristic of the liquid crystal display 1 (FIG. 4). By selecting the values of the variable resistors 27 and the segment common signal generator 29, a linear gradation display can be realized. In addition, since the segment common pulse is a divided pulse having the same phase and opposite phase as the drive pulse 11 supplied to the common electrode 9, there is no occurrence of charge bias between the electrodes that causes deterioration of the liquid crystal.

In the liquid crystal display 1 of this embodiment, the amplitude of the drive pulse applied to each of the segment electrodes 12 to 18 can be varied by a variable resistor. This resistance value is controlled by the speed at which the measured value increases or decreases. By doing so, it is possible to change the gradation intermediate luminance that looks like an afterimage of the display irrespective of the display data, and it is possible to realize a display like a radar scope.

[0012]

As described above, according to the present invention, the structure is connected to a drive circuit for outputting a high-level or low-level signal from a plurality of output terminals and corresponding to each of the drive circuits. A liquid crystal display having a divided segment, a segment common signal generating circuit for outputting a pulse having a variable amplitude, and an output terminal of the drive circuit connected via a first resistor, A liquid crystal display device comprising: a voltage synthesizing circuit each connected to the segment common signal generating circuit via a second resistor to receive a pulse from the segment common signal generating circuit and a pulse from the driving circuit. Did
There is no biased charge between the electrodes which leads to deterioration of the liquid crystal display,
There is an effect that a new and high-quality display feeling can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a liquid crystal display device according to one embodiment of the present invention.

FIG. 2 is a waveform diagram of each section for explaining the operation of the liquid crystal display device of FIG.

FIG. 3 is a waveform diagram showing an effective voltage value supplied to each segment of the liquid crystal display.

FIG. 4 is a characteristic diagram showing an effective voltage-transmittance characteristic of the liquid crystal display.

FIG. 5 is a block diagram illustrating an example of a conventional liquid crystal display device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid crystal display 24a-24g Exclusive OR circuit (drive circuit) 25a-25f Gate circuit (drive circuit) 26 1st resistor (voltage synthesis circuit) 27 2nd resistor (voltage synthesis circuit) 29 Generating segment common signal circuit

Claims (1)

(57) [Claims] 1. A drive circuit for outputting a high-level or low-level signal from a plurality of output terminals, a liquid crystal display having segments connected to the respective drive circuits, and a variable amplitude. A segment common signal generating circuit for outputting a pulse is connected to the output terminal of the drive circuit via a first resistor, and each of the output terminals is connected to the segment common signal generating circuit via a second resistor. And a voltage synthesizing circuit to which a pulse from the segment common signal generating circuit and a pulse from the driving circuit are supplied.