JP2006162909A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To set the optimal overdrive quantity even when there is difference in temperature at upper and lower parts of a liquid crystal display panel in a liquid crystal display device. <P>SOLUTION: The liquid crystal display device has a liquid crystal display panel and a drive means which controls and drives the liquid crystal display panel, the drive means has an overdrive processing means, divides the display screen of the liquid crystal display panel into m pieces in a first direction, divides it into n pieces in a second direction different from the first direction, the overdrive processing means changes the overdrive quantity by every area divided into (m×n) of the liquid crystal display panel. The display device has a plurality of sensors which measures temperature of the liquid crystal display panel and changes the overdrive quantity of the areas divided into (m×n) of the liquid crystal display panel based on the measured results of the plurality of temperature sensors. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a liquid crystal display device, and more particularly to a technique effective when driven by overdrive.

In a liquid crystal display device, an overdrive driving method is known as a technique for improving moving image display.
In this overdrive driving method, a method of changing the overdrive amount according to the temperature of the liquid crystal display panel is also known. (See Patent Document 1 and Patent Document 2 below)

As prior art documents related to the invention of the present application, there are the following.
JP 2004-133159 A JP 2004-107996 A

In Patent Document 1 and Patent Document 2 described above, the overdrive amount is changed depending on the temperature of the liquid crystal display panel.
However, in a liquid crystal display panel for TV use, there is a temperature difference between the top and bottom of the liquid crystal display panel, and the response speed of the liquid crystal changes due to this temperature difference.
Therefore, even if the overdrive amount is changed depending on the temperature of the liquid crystal display panel as in the above-described Patent Document 1 and Patent Document 2, for example, in the case of a liquid crystal display panel having a large temperature difference between the upper and lower sides, If the overdrive amount is determined based on the upper temperature, the overdrive amount is not the appropriate overdrive amount on the lower side of the liquid crystal display panel. In any case, the user who observes the liquid crystal display panel feels uncomfortable with the image displayed on the liquid crystal display panel. It becomes.
The present invention has been made to solve the above-described problems of the prior art, and an object of the present invention is to provide an optimum liquid crystal display device even when there is a temperature difference between the upper and lower sides of the liquid crystal display panel. It is an object of the present invention to provide a technique that can set an overdrive amount.
The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

Of the inventions disclosed in this application, the outline of typical ones will be briefly described as follows.
In order to solve the above-described problems, the present invention includes a liquid crystal display panel and a driving unit that controls and drives the liquid crystal display panel, and the driving unit includes a liquid crystal display device having an overdrive processing unit. The display screen of the liquid crystal display panel is divided into m in a first direction, or the display screen of the liquid crystal display panel is divided into m in a first direction and n in a second direction different from the first direction. The overdrive processing means changes the overdrive amount for each of the m divided areas of the liquid crystal display panel or for each of the (m × n) divided areas of the liquid crystal display panel.
In the present invention, a plurality of temperature sensors for measuring the temperature of the liquid crystal display panel are provided, and the liquid crystal display panel is divided into each of the m divided regions or the liquid crystal based on the measurement results of the plurality of temperature sensors. The overdrive amount is changed for each of the (m × n) divided areas of the display panel.

The effects obtained by the representative ones of the inventions disclosed in the present application will be briefly described as follows.
According to the liquid crystal display device of the present invention, an optimum overdrive amount can be set even when there is a temperature difference between the upper and lower sides of the liquid crystal display panel.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
In all the drawings for explaining the embodiments, parts having the same functions are given the same reference numerals, and repeated explanation thereof is omitted.
[Configuration of Liquid Crystal Display Module as a Premise of the Present Invention]
FIG. 1 is a block diagram showing a circuit configuration of a TFT liquid crystal display module which is a premise of the present invention.
The liquid crystal display module shown in FIG. 1 includes a liquid crystal display panel 100, a display control device 110, a power supply circuit 120, a drain driver 130, and a gate driver 140.
FIG. 2 is a diagram showing an equivalent circuit of an example of the liquid crystal display panel 100 shown in FIG.
As shown in FIG. 2, the liquid crystal display panel 100 has a plurality of pixels formed in a matrix.
Each pixel has a thin film transistor (TFT), and the source electrode of the thin film transistor (TFT) of each pixel is connected to the pixel electrode (ITO1).
In addition, since a liquid crystal layer is provided between the pixel electrode (ITO1) and the common electrode (also referred to as a counter electrode or a common electrode) (ITO2), the pixel electrode (ITO1) and the common electrode (ITO2) are not provided. The liquid crystal capacitors (CLC) are equivalently connected.
Further, a storage capacitor (CS) is connected between the source electrode of the thin film transistor (TFT) and the common electrode (ITO2).
In the liquid crystal display panel 100 shown in FIG. 2, the drain electrodes of the thin film transistors (TFTs) of the respective pixels arranged in the column direction are connected to the drain lines (also referred to as video lines) D, and the drain lines D are arranged in the column direction. Are connected to a drain driver 130 for applying a gradation voltage to the liquid crystal of each pixel.
A gate electrode of a thin film transistor (TFT) in each pixel arranged in the row direction is connected to a gate line (also referred to as a scanning line) G, and each gate line G corresponds to each pixel in the row direction for one horizontal scanning time. The gate driver 140 supplies a scanning drive voltage (positive bias voltage or negative bias voltage) to the gate electrode of the thin film transistor (TFT).

The display control device 110 is a drain driver based on display control signals and display data (R, G, B) of clock signals, display timing signals, horizontal synchronization signals, vertical synchronization signals transmitted from the outside. 130 and the gate driver 140 are controlled and driven.
The power supply circuit 120 supplies a gray scale reference voltage to the drain driver 130, supplies a scanning drive voltage to the gate driver 140, and supplies a common voltage to the common electrode (ITO2).
The power supply circuit 120 supplies the power supply voltages of the drain driver 130 and the gate driver 140 to the drain driver 130 and the gate driver 140.
The gate driver 140 sequentially supplies a scanning signal voltage for turning on the thin film transistor (TFT) to the gate line G for each horizontal scanning line for one horizontal scanning time to turn on the thin film transistor (TFT).
Also, the drain driver 130 supplies a video signal voltage to the drain line D, applies a video signal voltage to the pixel electrode (ITO1) through the turned-on thin film transistor (TFT), and applies the video signal voltage to each pixel. And the pixel capacitance (CLC) between the pixel electrode (ITO1) and the common electrode (ITO2) is charged to a predetermined voltage.
Based on this charging voltage, an image is displayed by changing the alignment direction of the liquid crystal molecules of each pixel.
With the above operation, an image is displayed on the liquid crystal display panel 100.

In the liquid crystal display module of the embodiment of the present invention, the display control device 110 shown in FIG. 1 has an overdrive function.
Next, the principle of overdrive processing will be described with reference to FIGS.
As shown in the upper side of FIG. 3, in normal driving, input data becomes display data as it is.
At this time, when voltage driving is performed with the waveform shown by the solid line in FIG. 4, the luminance response, that is, the liquid crystal response time is slower than one frame period (16.6 ms), so that the image change cannot be followed and tailing occurs.
Therefore, as shown by the waveform shown by the broken line in FIG. 4, the luminance response can be accelerated by applying the overdrive voltage to the frame in which the image has changed, and the tailing can be reduced.
This can be achieved with the lower method of FIG.
The previous frame data is created by the 1 frame delay circuit 111. Next, the data comparison circuit 112 compares the current frame data with the previous frame data. In accordance with the comparison result in the data comparison circuit 112, the data operation circuit 113 appropriately manipulates the input data to obtain display data.
As a specific circuit example, the 1-frame delay circuit 111 includes a frame memory (usually SDRAM) and a memory control circuit, the data comparison circuit 112 multiplies the subtraction circuit, and the data operation circuit 113 multiplies the subtraction result by a coefficient. A multiplication circuit and an addition circuit for adding the multiplication result to input data are constituted.

In the liquid crystal display module of the embodiment of the present invention, as shown in FIG. 5, the display screen of the liquid crystal display panel is divided into m in the vertical direction and n in the horizontal direction.
Then, the overdrive amount is changed for each of the (m × n) divided areas on the surface of the liquid crystal display panel.
For example, in the area of FIG. 5A, the overdrive amount is increased to increase the overdrive, and in FIG. 5B, the overdrive amount is decreased to decrease the overdrive. For example, the overdrive process is changed for each divided area.
In order to divide into m in the vertical direction, it is sufficient to have a counter that recognizes the beginning of the frame and counts the horizontal sync signal (Hsync) and performs division control, and to divide into n in the horizontal direction. It is sufficient to have a counter that recognizes the head in the horizontal direction and counts the reference clock signal (DCLK) and performs division control.

FIG. 6 is a diagram showing a configuration for switching overdrive processing in the liquid crystal display module of the embodiment of the present invention.
In FIG. 6, reference numeral 200 denotes overdrive means, and this overdrive means 200 constitutes the data comparison circuit 112 and the data operation circuit 113 shown in FIG. 3. Reference numeral 201 denotes a frame memory. The frame memory 201 constitutes a one-frame delay circuit 111 shown in FIG. The overdrive means 200 and the frame memory 201 are provided in the display control device 110 shown in FIG.
Reference numeral 202 denotes X temperature sensors for monitoring the temperature of the liquid crystal display panel.
In the configuration shown in FIG. 6, the X temperature sensor measurement results are directly input to the overdrive means 200, and overdrive processing is switched according to the measurement result of the temperature sensor 202. That is, according to the measurement result of the temperature sensor 202, the overdrive amount is changed for each (m × n) divided area of the liquid crystal display panel.
FIG. 7 is a diagram showing another configuration for switching overdrive processing in the liquid crystal display module of the embodiment of the present invention.
In the configuration shown in FIG. 7, the measurement results of the X temperature sensors 202 that monitor the temperature of the liquid crystal display panel are directly input to the microcomputer 210 that controls the overdrive means 200, and the microcomputer 210 follows the measurement results of the temperature sensor 202. The overdrive means 200 is controlled to switch overdrive processing.

FIG. 8 is a diagram for explaining an example of a method for attaching the temperature sensor 202 in the liquid crystal display module of the present embodiment.
In FIG. 8, AR is a display area, 220 is a glass substrate of a liquid crystal display panel, 230 is an external housing, and white circles indicate sensor mounting positions.
In general, a liquid crystal display panel is configured by enclosing a liquid crystal between a pair of glass substrates. And the temperature sensor 202 is arrange | positioned in the position covered with the external housing | casing 230 on the circumference | surroundings of one glass substrate of a pair of glass substrates.
Although the temperature sensor attachment position varies depending on the situation, for example, the following positions (1) to (3) are assumed.
(1) When the display screen of the liquid crystal display panel is divided into two parts, the temperature sensor 202 is attached on either the left or right side of the glass surface, and the setting of the overdrive amount is changed based on the temperature difference. The setting here is a constant of an arithmetic expression for determining the overdrive amount.
(2) When the display screen of the liquid crystal display panel is divided into three parts, the temperature sensor 202 is attached at equal intervals on either the left or right side of the glass surface, and the overdrive amount is set based on the temperature difference. To change.
(3) When the display screen of the liquid crystal display panel is divided into two in the left-right direction, the temperature sensor 202 is attached to either the upper or lower side of the glass surface, and the overdrive setting is changed based on the temperature difference.

Further, the temperature sensor 202 may be disposed in a driver (the drain driver 130 and the gate driver 140 in FIG. 1) disposed around one substrate of the liquid crystal display panel.
Further, in general, a liquid crystal display device such as a liquid crystal display module includes a backlight disposed on the side opposite to the display surface of the liquid crystal display panel. You may make it arrange | position the temperature sensor 202 in this backlight.
As described above, according to the present embodiment, for example, even if there is a temperature difference between the upper and lower portions of the liquid crystal display panel, the overdrive process is changed at the upper and lower portions of the display screen, and the entire liquid crystal display panel screen due to the temperature difference is changed. Since the variation in response speed is suppressed, it is possible to relieve the user who observes the liquid crystal display panel from feeling uncomfortable with the image displayed on the liquid crystal display panel.
As mentioned above, the invention made by the present inventor has been specifically described based on the above embodiments. However, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention. Of course.

1 is a block diagram showing a circuit configuration of a TFT liquid crystal display module which is a premise of the present invention. It is a figure which shows the equivalent circuit of an example of the liquid crystal display panel shown in FIG. It is a figure for demonstrating the principle of an overdrive process. It is a figure for demonstrating the principle of an overdrive process. In the liquid crystal display module of the Example of this invention, it is a figure which shows the state which divided the display screen of the liquid crystal display panel into m by the vertical direction, and n by the horizontal direction. It is a figure which shows the structure for switching an overdrive process in the liquid crystal display module of the Example of this invention. It is a figure which shows the other structure for switching an overdrive process in the liquid crystal display module of the Example of this invention. It is a figure for demonstrating an example of the attachment method of a temperature sensor in the liquid crystal display module of the Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Liquid crystal display panel 110 Display control apparatus 111 1 Frame delay circuit 112 Data comparison circuit 113 Data operation circuit 120 Power supply circuit 130 Drain driver 140 Gate driver 200 Overdrive means 201 Frame memory 202 Temperature sensor 210 Microcomputer 220 Glass substrate 230 External housing | casing D Drain line G Gate line AR Display area

Claims (7)

A liquid crystal display panel;
Driving means for controlling and driving the liquid crystal display panel;
The drive means includes overdrive processing means,
Dividing the display screen of the liquid crystal display panel into m in the first direction;
The liquid crystal display device, wherein the overdrive processing means changes an overdrive amount for each of the m divided areas of the liquid crystal display panel. A liquid crystal display panel;
Driving means for controlling and driving the liquid crystal display panel;
The drive means includes overdrive processing means,
Dividing the display screen of the liquid crystal display panel into m in a first direction and n in a second direction different from the first direction;
The liquid crystal display device, wherein the overdrive processing means changes an overdrive amount for each of the (m × n) divided areas of the liquid crystal display panel. A plurality of temperature sensors for measuring the temperature of the liquid crystal display panel;
The liquid crystal display device according to claim 1, wherein an overdrive amount for each of the m divided regions of the liquid crystal display panel is changed based on measurement results of the plurality of temperature sensors. A plurality of temperature sensors for measuring the temperature of the liquid crystal display panel;
The liquid crystal display device according to claim 2, wherein an overdrive amount of the (m × n) divided region of the liquid crystal display panel is changed based on measurement results of the plurality of temperature sensors.   5. The liquid crystal display device according to claim 3, wherein the plurality of temperature sensors are arranged at a position covered with an external housing on the periphery of one substrate of the liquid crystal display panel. Having a driver arranged around one substrate of the liquid crystal display panel;
The liquid crystal display device according to claim 3, wherein the plurality of temperature sensors are disposed in the driver. A backlight disposed on the opposite side of the display surface of the liquid crystal display panel;
The liquid crystal display device according to claim 3, wherein the plurality of temperature sensors are arranged in the backlight.

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