JPH07219482A - Liquid crystal driving circuit - Google Patents

Abstract

PURPOSE:To drive a plurality of liquid crystal layers with the driving data sent from a color specifying circuit for individual liquid crystal layers. CONSTITUTION:Data driving a plurality of liquid crystal layers are sent to a gamma correcting/polarity inverting circuit 24, the driving voltages 25 are generated by the gamma correcting/polarity inverting circuit 24, and they are applied to a plurality of liquid crystal layers via a source driver 23 in this liquid crystal driving circuit. A memory circuit 26 is provided between the color specifying circuit 28 and the gamma correcting/polarity inverting circuit 24, and combinations of a plurality of driving data 29 and the driving voltage data 27 corresponding to the combinations are stored in the memory circuit 26. When a plurality of driving data 29 are sent from the color specifying circuit 28, the driving voltage data 27 corresponding to a plurality of driving data 29 are sent to the gamma correcting/polarity inverting circuit 24 from the memory circuit 26, and the driving voltages 25 are generated from the driving voltage data 27 by the gamma correcting/polarity inverting circuit 24.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal drive circuit, and more particularly to a liquid crystal drive circuit for driving a plurality of liquid crystal layers for each liquid crystal layer.

[0002]

2. Description of the Related Art FIG. 4 shows a conventional method of driving a liquid crystal using a switching element such as a TFT (thin film transistor). In FIG. 4, 1 is a liquid crystal layer, 2 is a counter electrode, 3 is a pixel electrode, and 4 is a T for controlling application of voltage to the pixel electrode 3.
FT and 5 are source lines for applying a voltage to the pixel electrode 3,
Reference numeral 6 is a gate line for controlling on / off of the TFT 4.

When a voltage is applied to the liquid crystal layer 1, a voltage having a necessary difference with respect to the counter electrode 2 may be applied to the pixel electrode 3. For example, assuming that the counter electrode 2 is 0 V, when a voltage of ± 5 V is applied to the liquid crystal layer 1 alternately, a voltage of ± 5 V is applied to the pixel electrode 3 alternately for each field.

However, the above-mentioned method cannot deal with the case where the liquid crystal layer 1 has a multi-layer structure.

That is, FIG. 5 shows a structure in which the liquid crystal layer 1 has three layers. In FIG. 5, 1a is a first liquid crystal layer, 1b is a second liquid crystal layer, 1c is a third liquid crystal layer, 2 is a counter electrode, 3a.
Is a first pixel electrode formed between the first liquid crystal layer 1a and the second liquid crystal layer 1b, and 3b is a second pixel electrode formed between the second liquid crystal layer 1b and the third liquid crystal layer 1c. Pixel electrodes 3c are third pixel electrodes formed below the third liquid crystal layer 1c. The voltage is applied to the first pixel electrode 3a by applying the first TFT.
4a, the application of voltage to the second pixel electrode 3a is controlled by the second TFT 4b, and the application of voltage to the third pixel electrode 3c is controlled by the third TFT 4c. 6a is a first gate line for controlling on / off of the first TFT 4a, 6b is a second gate line for controlling on / off of the second TFT 4b, and 6c is on / off of the third TFT 4c.
It is a third gate line that controls turning off. A drive voltage is applied to each of the first pixel electrode 3a, the second pixel electrode 3b, and the third pixel electrode 3c from the source line 5.

FIG. 6 shows a drive circuit of the liquid crystal device as described above. In FIG. 6, 7 is a liquid crystal panel, 8 is a gate driver that controls switching of the TFTs 4a to 4c (see FIG. 5) in the liquid crystal panel 1, and 9 is a pixel electrode 3a in the liquid crystal panel 1.
3c (see FIG. 5), the source driver 10 controls the voltage application to the source driver 9, and the source driver 9 applies a voltage 11 to the source driver 9.
A gamma correction / polarity inversion circuit for supplying a color, a color designation circuit 12 for sending data for driving a plurality of liquid crystal layers (see FIG. 5) to the gamma correction / polarity inversion circuit 10, and a timing 14 for the gate driver 8 and the source driver 9. Send a signal,
This is a controller that sends a polarity inversion signal to the gamma correction / polarity inversion circuit 10.

When the liquid crystal device of FIG. 5 is driven by the drive circuit of FIG. 6, it becomes as shown in FIG. That is, the data 13 for driving the three liquid crystal layers 1 a, 1 b, and 1 c is sent from the color designating circuit 12 to the gamma correction / polarity reversing circuit 15. In the gamma correction / polarity inversion circuit 15, three liquid crystal layers 1a,
± 5 when the data 13 that drives 1b and 1c is "1"
V is output and supplied to the source driver 9, and is supplied to the corresponding first pixel electrode 3a to third pixel electrode 3c. When the data 13 for driving the three liquid crystal layers 1a, 1b, 1c is "0", 0V is output and supplied to the corresponding first pixel electrode 3a to third pixel electrode 3c.

However, for example, three liquid crystal layers 1a, 1
Taking the case where the data 13 for driving b and 1c are all “1” as an example, when the counter electrode 1 is 0 V, the first pixel electrode 3
Since + 5V is applied to a, 5V is applied to the first liquid crystal layer 1a, but 5V is also applied to the second pixel electrode 3b, so that an effect is applied to the second liquid crystal layer 1b. The voltage becomes 0V, and since 5V is also applied to the third pixel electrode 3c, the effective voltage applied to the third liquid crystal layer 1c also becomes 0V.

Therefore, when there are three liquid crystal layers 1, the first liquid crystal layer 1a is dealt with by supplying a necessary difference voltage to the first pixel electrode 3a with reference to the voltage of the counter electrode 1. However, there is a problem that the second liquid crystal layer 1b and the third liquid crystal layer 1c cannot be driven by the conventional liquid crystal drive circuit.

The present invention has been invented in view of the above problems of the prior art, and an object of the invention is to provide a liquid crystal drive circuit capable of driving a plurality of liquid crystal layers layer by layer. is there.

[0011]

To achieve the above object, the liquid crystal drive circuit of the present invention sends data for driving a plurality of liquid crystal layers from a color designation circuit to a gamma correction / polarity inversion circuit, In a liquid crystal drive circuit that generates a drive voltage with a gamma correction / polarity inversion circuit and applies this drive voltage to a plurality of liquid crystal layers via a source driver to drive each liquid crystal layer, the color designation circuit and gamma correction / A storage circuit is provided between the polarity inversion circuits, a combination of a plurality of drive data and drive voltage data corresponding to the combination is stored in the storage circuit, and when a plurality of drive data is sent from the color designating circuit, The drive voltage data corresponding to the plurality of drive data is sent from the storage circuit to the gamma correction / polarity inversion circuit, and the gamma correction / polarity inversion circuit generates a drive voltage from the drive voltage data. Was to so that.

[0012]

As described above, if the storage circuit for storing the combination of drive data sent from the color designation circuit and the drive voltage data corresponding to the combination is provided between the color designation circuit and the gamma correction / polarity inversion circuit, The drive data sent from the color designating circuit can drive a plurality of liquid crystal layers for each liquid crystal layer.

[0013]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. FIG. 1 is a diagram showing an embodiment of a liquid crystal drive circuit according to the present invention, in which 21 is a liquid crystal panel, 22 is a gate driver for controlling switching of TFTs (see FIG. 5) in the liquid crystal panel 21, and 23 is a liquid crystal. A source driver that controls the voltage application to the pixel electrodes (see FIG. 5) in the panel 21, 24 is a voltage applied to the source driver 23
Gamma correction / polarity inversion circuit for supplying the voltage, 26 is a storage circuit for sending the drive voltage data 27 to the gamma correction / polarity inversion circuit 24, 28 is a plurality of liquid crystal layers in the storage circuit 26 (see FIG. 5).
Is a color designating circuit for sending the driving data 29, and 30 is a controller for sending a timing signal to the gate driver 22 and the source driver 23, and sending a polarity inversion signal to the gamma correction / polarity inversion circuit 24. The liquid crystal panel 21 itself is the same as the conventional liquid crystal panel shown in FIG. 5, and will be described with reference to FIG. FIG. 2 shows drive data 29 of a plurality of liquid crystal layers sent from the color designation circuit 28 to the storage circuit 26. For example, turn on / off the three liquid crystal layers 1a, 1b, and 1c.
There are eight combinations when operating by FF binary selection.

FIG. 3 shows the driving data 2 for the plurality of liquid crystal layers.
8 combinations of 9 and drive voltage data corresponding to this combination are shown. In FIG. 3, the color designating circuit 28
The drive data 29 of the plurality of liquid crystal layers sent from the memory circuit 26 to the memory circuit 26 is indicated by “0” and “1”. The data corresponding to the combination of the drive data 29 of the plurality of liquid crystal layers is obtained as follows. That is, the counter electrode 1 for the first liquid crystal layer 1a shown in FIG. 5, the first pixel electrode 3a for the second liquid crystal layer 1b, and the second pixel electrode 3b for the third liquid crystal layer 1c are set to 0V. Each liquid crystal layer 1
Values of drive voltage combinations for applying effective voltages of ON = 5V and OFF = 0V to a, 1b, and 1c are shown. The first pixel electrode 3a serves as the counter electrode of the second liquid crystal layer 1b, and the second pixel electrode 3b serves as the counter electrode of the third liquid crystal layer 1c. A voltage is applied to the first liquid crystal layer 1a (ON
In this case, if the counter electrode 1 is 0V, 5V is applied to the first pixel electrode 3a, and if no voltage is applied to the first liquid crystal layer 1a (OFF), if the counter electrode 1 is 0V. , The first pixel electrode 3a is also set to 0V. When a voltage is applied (ON) to the second liquid crystal layer 1b, 5 is applied to the first pixel electrode 3a.
If V is applied, the second pixel electrode 3b is set to 0V, and if the first pixel electrode 3a is 0V, the second pixel electrode 3b is set to 5V. When the voltage is not applied (OFF) to the second liquid crystal layer 1b, the voltage of the second pixel electrode 3b is made the same as the voltage of the first pixel electrode 3a. Third liquid crystal layer 1
When a voltage is applied to c (ON), the second pixel electrode 3
If 5V is applied to b, the third pixel electrode 3c is set to 0
V, and if the second pixel electrode 3b is 0V, the third pixel electrode 3c is 5V. When the voltage is not applied to the third liquid crystal layer 1c (OFF), the voltage of the third pixel electrode 3c is made the same as the voltage of the first pixel electrode 9. Therefore,
For example, when the drive data 29 is “000”, the drive voltage data corresponding to it is “000”, and the drive data 2
When 9 is "001", the corresponding drive voltage data is "001". When the drive data 29 is "010", the corresponding drive voltage data is "011" and the drive data 29 is "011". In this case, the drive voltage data corresponding to that is “010”, and the drive data 29
Is "100", the corresponding drive voltage data is "111". If the drive data 29 is "101", the corresponding drive voltage data is "110". If the drive data 29 is "110". , The drive voltage data corresponding to that becomes “100”, and the drive data 29
Is "111", the corresponding drive voltage data is "101". The drive data 29 and the drive voltage data 27 are stored in the storage circuit 26.

That is, the drive data 29 is transferred to the color designation circuit 2
The data is read from 8 to the storage circuit 26, one of the eight combinations is determined, and the drive voltage data 27 corresponding to the combination is sent to the gamma correction / polarity inversion circuit 24. The gamma correction / polarity inversion circuit 24 generates 0V when the drive voltage data is "0" and 5V when the drive voltage data is "1".
To generate. That is, the gamma correction / polarity inversion circuit 24
Then, when the drive voltage data 27 is “000”, the gamma correction / polarity inversion circuit 24 generates the drive voltage 25 of “0V” “0V” “0V”, and the drive voltage data 27 is “00”.
In the case of "1", the gamma correction / polarity inversion circuit 24 outputs "0V".
The drive voltage 25 of "0V""5V" is generated, and when the drive voltage data 27 is "010", the gamma correction / polarity inversion circuit 24 generates the drive voltage 25 of "0V""5V""5V". When the drive voltage data 27 is “010”, the gamma correction / polarity inversion circuit 24 generates the drive voltage 25 of “0V” “5V” “0V”, and the drive voltage data 27 is “11”.
In the case of "1", the gamma correction / polarity inversion circuit 24 outputs "5V".
The drive voltage 25 of "5V" and "5V" is generated, and when the drive voltage data 27 is "110", the gamma correction / polarity inversion circuit 24 generates the drive voltage 25 of "5V""5V""0V". When the drive voltage data 27 is "100", the gamma correction / polarity inversion circuit 24 generates the drive voltage 25 of "5V""0V""0V", and the drive voltage data 27 is "10".
In the case of "1", the gamma correction / polarity inversion circuit 24 outputs "5V".
The drive voltage 25 of “0V” and “5V” is generated.

The drive voltage 25 is applied to the controller 3
When the polarity inversion signal is input from 0, the polarity is inverted and generated.

The group of drive voltages 25 described above is sent to the source driver 23, and is sent from the source driver 23 to the corresponding source lines 6a, 6b, 6c (see FIG. 5). this,
The timing for outputting the driving voltage 25 is the controller 30.
Controlled by the control signal from.

As described above, according to this embodiment, the combination of drive voltages can be controlled by a digital signal.

In the above embodiment, the memory circuit 26 generates a combination of outputs from digital data, but any memory having a function of converting the data may be used. For example, a logic circuit that outputs a specified output for a specified input can be used. Further, by providing an A / D conversion circuit in front of the memory circuit 26, a driving circuit corresponding to an analog input signal can be obtained.

The plurality of liquid crystal layers 1a, 1b, 1c are
For example, it may be a composite layer of liquid crystal and polymer such as polymer dispersed liquid crystal.

[0021]

As described above, according to the liquid crystal drive circuit of the present invention, a storage circuit is provided between the color designation circuit and the gamma correction / polarity inversion circuit, and a combination of a plurality of drive data is provided in the storage circuit. The drive voltage data corresponding to the combination is stored, and when a plurality of drive data is sent from the color designation circuit, the drive voltage data corresponding to the plurality of drive data is sent from the storage circuit to the gamma correction / polarity inversion circuit. Since the gamma correction / polarity inversion circuit generates the drive voltage from the drive voltage data, the drive data sent from the color designating circuit can drive a plurality of liquid crystal layers for each liquid crystal layer, Therefore, it becomes possible to drive a plurality of liquid crystal layers.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a liquid crystal drive circuit according to the present invention.

FIG. 2 is a diagram showing a combination of drive data.

FIG. 3 is a diagram showing drive data, drive voltage data, and drive voltage.

FIG. 4 is a diagram showing a conventional single-layer liquid crystal device.

FIG. 5 is a diagram showing a conventional multi-layer liquid crystal device.

FIG. 6 is a diagram showing a configuration of a conventional liquid crystal drive circuit.

FIG. 7 is a diagram showing control data of a conventional liquid crystal drive circuit.

[Explanation of symbols]

21 ... Liquid crystal panel, 22 ... Gate driver, 2
3 ... Source driver, 24 ... Gamma correction / inversion circuit, 25 ... Drive voltage, 26 ... Memory circuit,
27 ... Driving voltage data, 28 ... Color designation circuit, 2
9 ... Drive data

Claims (5)

[Claims] 1. A data for driving a plurality of liquid crystal layers is sent from a color designation circuit to a gamma correction / polarity inversion circuit, a drive voltage is generated by this gamma correction / polarity inversion circuit, and this drive voltage is supplied to a source driver. A liquid crystal drive circuit that drives each liquid crystal layer by applying it to a plurality of liquid crystal layers via a storage circuit between the color designating circuit and the gamma correction / polarity inversion circuit And driving voltage data corresponding to the combination thereof are stored. When a plurality of driving data are sent from the color designating circuit, the driving voltage data corresponding to the plurality of driving data are stored in the storage circuit to the gamma correction / polarity. A liquid crystal drive circuit characterized in that the gamma correction / polarity inversion circuit generates a drive voltage from drive voltage data by sending it to an inversion circuit. 2. The liquid crystal drive circuit according to claim 1, wherein the drive voltage data is determined on the basis of a voltage applied to a pixel electrode in an upper layer or a voltage applied to a counter electrode in a lower layer. 3. The drive data sent to the storage circuit is 2
The liquid crystal drive circuit according to claim 1, wherein the liquid crystal drive circuit is value data. 4. The liquid crystal drive circuit according to claim 1, wherein the drive data sent to the gamma correction / polarity inversion circuit is binary data. 5. The liquid crystal drive circuit according to claim 1, wherein the liquid crystal layer is a composite layer of a liquid crystal layer and a polymer layer.