JPH11242203A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an efficient and miniaturizable liquid crystal display device having high display quality. SOLUTION: A liquid crystal cell 1 is a screen-divided simple matrix and a scanning circuit 2 and a signal circuit 3 are used for each divided screen. For a correction circuit 6 for generating display improvement data corresponding to image signals, one each of an integrated circuit element is allocated to each divided screen and the integrated circuit element is integrally provided with a screen processing part 61 (crosstalk correction signal generation circuit) for generating the display improvement data corresponding to the image signals and a cell processing part 62 for monitoring the voltage/clock or the like of the entire liquid crystal cell and generating required signals. The cell processing part 62 is constituted of a boundary screen processing circuit, a voltage abnormality detection circuit, a clock abnormality detection circuit, a waveform rounding correction circuit and AC signal generation circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called divided screen liquid crystal display device.

[0002]

2. Description of the Related Art A so-called simple matrix type liquid crystal display device having a conventional orthogonal electrode group and no active element such as a transistor at a pixel intersection is disclosed in JP-A-6-274132. As described above, in order to eliminate undesirable display (crosstalk) such as faint shadow, which is a specific problem of the simple matrix driving, a method of superimposing and applying a correction voltage by a calculation every time a waveform is changed has been made. Have been. When the screen is large and the display capacity increases, the screen is divided and displayed in order to secure a certain amount of scanning time and improve the display quality.

Referring to FIG. 2 as an example, orthogonal electrodes of the liquid crystal cell 1 are divided at the center of the screen, and a scanning circuit 2 and a signal circuit 3 are prepared in each divided area. The receiving circuit 4 which has received a signal from a device such as a word processor or a personal computer transmits the directly usable signal to the scanning circuit 2 or the signal circuit 3.
The signals are respectively distributed to the correction circuit 16 for generating display improvement data according to the image signal and to the cell processing circuit 17 for the entire liquid crystal cell, and the scanning of each divided area is performed via the bias circuit 5. The signal is supplied to the circuit 2 and the signal circuit 3.

[0004]

However, the correction circuit and the cell processing circuit often use the same signal,
Noise may be affected by the wiring layout,
In addition, if individual circuits are arranged on a substrate, the substrate becomes large, and a large component arrangement volume is required around and behind the liquid crystal display surface, which hinders miniaturization and thinning. In addition, the correction circuit is a relatively large circuit, and the processing must be adjusted depending on the compatibility between the device and the liquid crystal cell. Therefore, the integrated circuit device 1 having all functions incorporated in one liquid crystal display device is provided. There are many wastes in making individual pieces.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above points, and firstly, a liquid crystal cell having a screen divided into a plurality of parts by having a plurality of combinations of scanning electrode groups and signal electrode groups. A liquid crystal display comprising: a scanning circuit connected to the scanning electrode group; a signal circuit for providing pixel data to the signal electrode group according to an image signal; and a correction circuit for generating display improvement data according to the image signal. In the apparatus, the correction circuit includes an integrated circuit element integrally having a screen processing unit for each divided screen and a cell processing unit for performing signal processing on the entire liquid crystal cell, and more preferably an integrated circuit element. This is used for each divided screen.

The present invention also provides a liquid crystal cell having a plurality of orthogonal electrode groups, a scanning circuit connected to one of the orthogonal electrode groups in each group and outputting a scanning voltage to a predetermined electrode,
A signal circuit that supplies pixel data to the other electrode group according to the image signal, a screen processing unit that generates display improvement data according to the image signal in each group, and a voltage / clock of the entire liquid crystal cell are monitored and necessary. An integrated circuit element having an integrated cell processing unit for generating a signal is provided.

More preferably, the screen processing section comprises a crosstalk correction signal generation circuit, and the cell processing section includes a boundary screen processing circuit, a voltage abnormality detection circuit, a clock abnormality detection circuit, a waveform rounding correction circuit, and an AC signal generation circuit. It is configured by a circuit including one or more.

[0008]

FIG. 1 is a block diagram of a liquid crystal display device according to an embodiment of the present invention. In order to drive a liquid crystal cell having a large display capacity, a scanning signal is set to a large positive / negative voltage.
By setting the signal voltage to a voltage near the intermediate value between the positive selection voltage and the negative selection voltage, the scanning side can be driven at a low speed instead of using a large voltage, and the signal side can be driven at a high speed using a small voltage. A description will be given taking a liquid crystal display device as an example.

Reference numeral 1 denotes a liquid crystal cell having electrode groups orthogonal to each other. The liquid crystal cell forms a pixel at the intersection of these electrodes. For example, a field effect liquid crystal such as a super twisted nematic liquid crystal display can be used. These liquid crystal cells 1
These electrodes form a so-called simple matrix and have no active elements at pixel intersections. The liquid crystal cell 1 is divided into a plurality of screens (areas), and the divided screens (areas)
Each has a group of electrodes orthogonal to each other. Specifically, for example, a display surface of 1024 RGB × 768 pixels (color XGA) has 3072 (signal side) × 384 (scanning side) pixels of a two-screen configuration, and each of the upper and lower pixels separated by a center is 3072 pixels. Book signal electrodes and their intersection 76
It has eight scanning electrodes.

Reference numeral 2 denotes a scanning circuit for applying a scanning voltage to one electrode group for each screen (region) of the liquid crystal cell 1. In the above-described screen example, two sets of circuits having 384 outputs are provided. Consists of However, two sets is merely the number of sets as a scanning circuit, and does not mean that there are two integrated circuit elements. For example, it is constituted by using five integrated circuits of 156 outputs, and in this case, one integrated circuit which scans by covering two upper and lower parts, and the upper screen 312 to 384th and the lower screen 1 to 72 lines. It can be composed of elements. The scanning circuit 2 selects one of the positive and negative voltages -VL, + VH and the intermediate voltage Vm and supplies it to a predetermined electrode. Among them, -VL and + VH are selection voltages,
If the screen is divided vertically, scanning lines of the same order may be scanned one by one in order from the top in each screen (area). Here, line-sequential driving is taken as an example, but the present invention can be applied to a case where a plurality of electrodes are simultaneously scanned. In this case, for example, an applied voltage is selected according to an orthogonal function, The only difference is the number of electrodes for applying the selection voltage.

Reference numeral 3 denotes a signal circuit for applying a voltage corresponding to an image signal to the other electrode group of the liquid crystal cell 1, and particularly a signal circuit near an intermediate value between the positive selection voltage + VH and the negative selection voltage -VL of the scanning circuit 2. Two kinds of signal voltages -Vb and + Vb are selectively supplied to the electrodes according to the image signal. These selection voltages + V
The magnitudes of H, -VL and the signal voltage ± Vb are obtained according to the voltage averaging method. For example, when the XGA screen is divided into two, the number of scanning lines is 384, and when driving at 1/384 duty, The selection voltage ± 30 volts and the signal voltage ± Vb are approximately ± 1.5 volts depending on the optimum bias value. In this case, as the scanning voltage, one of the positive and negative selection voltages is selected at a constant cycle, which is selected according to the AC signal M, and the signal voltage output from the signal circuit 3 is the image voltage. Which of the two values is selected changes with the signal and the polarity inversion. When a plurality of rows are simultaneously scanned, only the voltage value is calculated by the orthogonal function, and there is no change in the application of the voltage averaging method.

Reference numeral 4 denotes a receiving circuit which receives a control signal or an image signal from a device such as a personal computer or a word processor, and may be a terminal or a simple buffer circuit. In many cases, it is often constituted by a conversion circuit, a waveform recovery circuit, or the like. Further, it may be constituted by a gate array or the like which receives a signal sent from a device such as a personal computer and supplies a control signal including a display signal and a timing signal to the scanning circuit 2 and the signal circuit 3.

A bias circuit 5 supplies a voltage of a predetermined value to the scanning circuit 2 and the signal circuit 3. The bias circuit 5 supplies at least a bias voltage such as a positive / negative selection voltage -VL, + VH, a signal voltage -Vb, + Vb, and an intermediate voltage Vm. And outputs a correction voltage corresponding to the correction circuit. The bias circuit 5 inputs a voltage VEE-VDD supplied from, for example, a personal computer in which the display device is incorporated as necessary to a voltage generation circuit (DC / DC converter), and outputs a positive / negative voltage −
VL and + VH are generated. The term "positive / negative" herein means not an absolute potential, for example, a potential specified for a power supply of a personal computer in which this display device is incorporated, but a potential with respect to a scanning voltage (intermediate voltage) Vm during non-scanning. expressing. Based on the selected voltage, a voltage having a predetermined bias value is obtained by a resistance dividing circuit, and the voltage is applied to a signal voltage + Vb, -V through a buffer circuit.
b and the intermediate voltage Vm are obtained. The driving voltage of the scanning circuit 2 and the driving voltage of the signal circuit 3 are the voltages VEE-VDD supplied from the personal computer in which the display device is incorporated.
May be used directly or may be newly generated by a voltage generation circuit.

A correction circuit 6 generates display improvement data according to an image signal sent from a device such as a personal computer. As is well known in the case of a simple matrix type liquid crystal display device, when a frame or bar is displayed, the extension of the frame or bar is shaded. This is often called crosstalk. There are various causes of crosstalk, and countermeasures include comparing the image signal for each line to see the rate of change, or comparing the overall white and black level ratios. They often use containers and registers. The main component of the correction circuit 6 is a screen processing unit 61 including such a crosstalk correction signal generation circuit.

However, what is characteristic here is that the screen processing section 61 operates not on the entire liquid crystal cell 1 but on a divided screen, and therefore, does not operate on the upper and lower divided screens. Consists of two integrated circuit elements. Since different image signals are handled for each divided screen, it is not necessary to store them in one package. Rather, storing them in one package increases the number of logics of integrated circuit elements, which is inconvenient. This is because it is more efficient to generate the crosstalk correction signal every time.

Another feature is that the cell processing unit 6 performs signal processing on the entire liquid crystal cell in the same integrated circuit element.
2. The cell processing unit 62 includes a boundary screen processing circuit, a voltage abnormality detection circuit, a clock abnormality detection circuit,
It monitors the voltage and clock of the entire liquid crystal cell, such as a waveform rounding correction circuit, an alternating signal generation circuit, and an upper screen lower screen drive switching circuit of the central scanning circuit element, and generates necessary signals. Only one is required. The reason why this is incorporated in each correction circuit 6 is that the crosstalk correction signal generation circuit processes the image signal while receiving various clocks, while the cell processing unit 62 detects the state of the image signal and the clock to detect the state of the image signal. Since a signal relating to the entire liquid crystal cell is generated, it is easier to process when arranged close to each other, and since these circuits have a relatively small number of logics, they are arranged at the corners of the screen processing unit 61 and used for the second and subsequent circuits. If there is no effect at all.

Since each circuit of the cell processing section 6 is separately scanned in the upper and lower directions, the influence of adjacent scanning lines on the display in the divided screen (area) and the boundary between the upper and lower screens (area) are different. The effect of adjacent scanning lines when scanning one scanning line is different and the display quality is not constant, so measures such as outputting the signal side data to the retrace period when scanning with the lowest scanning line on the upper screen Boundary screen processing circuit, voltage abnormality detection circuit that detects image quality instability due to voltage fluctuations, clock abnormality detection circuit that detects image distortion due to lack of various clocks, and applied voltage because the liquid crystal cell is a capacitive load A waveform rounding correction circuit that detects steepness and corrects the lost effective value of the applied voltage, and an AC signal generation circuit that inverts the applied polarity of the liquid crystal cell applied voltage under predetermined conditions When the scanning circuit is composed of five integrated circuits as described above, it is possible to incorporate an upper screen lower screen drive switching circuit that switches the central integrated circuit between upper screen driving and lower screen driving, etc. And
At least one circuit is preferably incorporated.

[0018]

As described above, according to the present invention, the correction circuit for each screen is provided, and the cell processing section is also incorporated in the integrated circuit element in which the correction circuit is incorporated. Process that makes it difficult to adjust by taking up space without requiring a large component arrangement volume around or on the back of the liquid crystal display surface. High display quality could be maintained without waste of expensive integrated circuit elements having large adjustment / change and unused functions.

[Brief description of the drawings]

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

FIG. 2 is a block diagram of a conventional liquid crystal display device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid crystal cell 2 Scanning circuit 3 Signal circuit 4 Receiving circuit 5 Bias circuit 6 Correction circuit 61 Screen processing part 62 Cell processing part

Continuation of the front page (72) Inventor Seiji Yamane 3-201 Minamiyoshikata, Tottori-shi, Tottori Sanyo Electric Co., Ltd. (72) Inventor Koji Maeda 3-201 Minamiyoshikata, Tottori-shi, Tottori Sanyo Electric Tottori

Claims (3)

[Claims] A liquid crystal cell having a plurality of screens divided by a plurality of combinations of a scanning electrode group and a signal electrode group, a scanning circuit connected to the scanning electrode group, and pixel data according to an image signal. And a correction circuit for generating display improvement data according to an image signal, the correction circuit,
A liquid crystal display device comprising: an integrated circuit element integrally including a screen processing unit for each divided screen and a cell processing unit for performing signal processing on the entire liquid crystal cell. 2. The liquid crystal display device according to claim 1, wherein the integrated circuit element is used for each divided screen. 3. A liquid crystal cell having a plurality of groups of orthogonal electrodes, a scanning circuit connected to one of the groups of orthogonal electrodes in each group and outputting a scanning voltage to a predetermined electrode, and pixel data according to an image signal. A signal circuit to be applied to the other electrode group, a screen processing unit for generating display improvement data according to an image signal in each group, and a cell processing unit for monitoring a voltage / clock of the entire liquid crystal cell and generating a necessary signal. A liquid crystal display device comprising an integrated circuit element provided integrally.