JP2010175685A - Liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make a light source efficiently emit light, in a liquid crystal display in which a display region is divided into a plurality of areas. <P>SOLUTION: In the liquid crystal display 100, a calculating part 5 calculates light quantity necessary for each area on the basis of an image signal; a CPU 121 decides the light quantity deciding order of a light source so that the order becomes an ascending order from the maximum light quantity area on the basis of light quantity necessary for each area by execution of a first deciding program 124b; the CPU decides light quantity of each light source and light quantity of a light source at the periphery of the light source with decided light quantity deciding order on the basis of the light quantity necessary for each area calculated by the calculating part 5 by execution of a second deciding program 124c; a backlight control part 11 makes each of the light source emit light with decided light quantity by execution of a backlight control program 124d. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a liquid crystal display device.

  In recent years, there has been known a liquid crystal display device that divides a display area into a plurality of areas and individually controls the light emission luminance of each light source corresponding to each area (see, for example, Patent Document 1). According to such a liquid crystal display device, a light source corresponding to a bright area can emit light with high luminance, while a light source corresponding to a dark area can emit light with low luminance, improving image quality and reducing power consumption. Can be achieved.

In such a liquid crystal display device, each area is irradiated with illumination light in which not only light from a light source disposed immediately below the area but also light diffused from the surrounding light sources is superimposed. Therefore, when determining the light amount of the light source corresponding to each area, it is necessary to consider the light amount of the light source arranged around the light source.
Patent Document 2 discloses a gradation correction table corresponding to a combination of a luminance level of a certain backlight illumination region (light source) and a luminance level of a backlight illumination region (light source) adjacent thereto for each pixel region (area). A display device that performs gradation correction based on data has been proposed (see, for example, Patent Document 2).

JP 2004-350179 A Patent No. 3523170

  In the method of determining the light amount of each light source as described above in consideration of the light amounts of the surrounding light sources, the light amount of each light source varies depending on the order of determining the light amount. Therefore, rather than simply determining the light intensity of each light source in the order in which they are arranged, it is more efficient to determine the light intensity of each light source in an appropriate order calculated based on the light intensity required for each area. It is possible to control the light source. However, the conventional techniques including Patent Document 2 have not proposed anything about the order of determining the light emission amount of the light source.

  An object of the present invention is to make a light source emit light more efficiently in a liquid crystal display device in which a display region is divided into a plurality of areas.

In order to solve the above-mentioned problem, the invention described in claim 1 is a liquid crystal display device comprising: a liquid crystal panel divided into a plurality of areas; and a backlight including a plurality of light sources corresponding one-to-one to the areas. ,
A calculation means for calculating a necessary light amount for each area based on an image signal;
First determining means for determining the light quantity determination order of the light source based on the light quantity required for each area calculated by the calculating means so as to be in ascending order from the area of the maximum light quantity;
Based on the amount of light necessary for each area calculated by the calculation means, the light amount of each light source and the light amounts of light sources around the light source are determined in the light amount determination order determined by the first determination unit. Second determining means for determining;
Backlight control means for controlling each of the light sources to emit light with the light amount determined by the second determination means;
It is characterized by providing.

The invention according to claim 2 is a liquid crystal display device comprising: a liquid crystal panel divided into a plurality of areas; and a backlight including a plurality of light sources corresponding one-to-one to the areas.
A calculation means for calculating a necessary light amount for each area based on an image signal;
First determining means for determining the light quantity determination order of the light source based on the light quantity required for each area calculated by the calculating means so as to be in ascending order from the area of the maximum light quantity;
Based on the amount of light necessary for each area calculated by the calculation means, the light amount of each light source and the light amounts of light sources around the light source are determined in the light amount determination order determined by the first determination unit. Second determining means for determining;
Backlight control means for controlling each of the light sources to emit light with the light amount determined by the second determination means;
With
A diffusion member for diffusing light emitted from each light source of the backlight is arranged on the front surface of the backlight.

According to the present invention, the calculation unit calculates the amount of light necessary for each area based on the image signal, and the first determination unit calculates the maximum amount of light based on the amount of light required for each area calculated by the calculation unit. The light quantity determination order of the light sources is determined so as to be in ascending order from the area, and the light quantity of each light source and the light source based on the light quantity required for each area calculated by the calculation means by the second determination means The light amount of the light source around the light source is determined in the light amount determination order determined by the first determination unit, and the backlight control unit controls the light sources to emit light with the light amount determined by the second determination unit. Is called.
That is, based on the light quantity required for each area, the light quantity determination order is determined so as to be in ascending order from the area of the maximum light quantity, and the light quantity of each light source is determined in the determined light quantity determination order. Therefore, in a liquid crystal display device in which the display area is divided into a plurality of areas, the light quantity of each light source is determined in order from the area with the highest light quantity, so that the light quantity in the entire backlight is reduced and is simply arranged. The light sources can be made to emit light more efficiently than when the light amounts of the respective light sources are determined in the order in which the light sources are emitted.

It is a block diagram which shows the principal part structure of the liquid crystal display device of this embodiment to which this invention is applied. FIG. 2A is a diagram schematically illustrating a display area of the liquid crystal panel of the present embodiment, and FIG. 2B is a diagram schematically illustrating the backlight of the present embodiment. It is an example of the light distribution memorize | stored in the light distribution memory | storage part. It is a flowchart which shows the flow of the light emission control processing of a light source. It is an example of the light quantity required for each area. It is the light quantity determination order determined based on the required light quantity of each area illustrated in FIG. It is a figure which shows the required light quantity of the area S (3, 4) with the 1st light quantity determination order. This is the light amount of each light source for irradiating the area S (3, 4) with the light amount “87”. It is a figure which shows the required light quantity of the area S (3, 4) with the 1st light quantity determination order, and the required light quantity of the area S (5, 2) with the 2nd light quantity determination order. This is the light amount of each light source for irradiating the area S (3, 4) with the light amount “87” and the area S (5, 2) with the light amount “84”. It is the light quantity of each light source for implement | achieving the light quantity shown in FIG. It is the light quantity of each light source for implement | achieving the light quantity shown in FIG. 5 calculated using the conventional method of calculating the light quantity of each light source L in the order arranged.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The scope of the invention is not limited to the illustrated example.

FIG. 1 is a block diagram showing a main configuration of the liquid crystal display device of the present embodiment. In FIG. 1, dotted lines indicate the flow of video data, and solid lines indicate the flow of control signals.
As shown in FIG. 1, for example, the liquid crystal display device 100 according to the present embodiment includes a signal input unit 1, a video processing unit 2, a timing control unit 3, a frame memory 4, a calculation unit 5 as a calculation unit, a correction unit 6, A liquid crystal panel 7, a scanning line driving unit 8, a signal line driving unit 9, a backlight 10, a backlight control unit 11, a control unit 12, and the like are provided.

  The signal input unit 1 includes, for example, an antenna and a tuner for receiving a television broadcast signal, various video terminals for receiving an image signal from an external device, and the like. Output to the processing unit 2.

  The video processing unit 2 includes an A / D conversion circuit, an RGB generation circuit, an image quality adjustment circuit, and the like, generates an RGB digital image signal based on the image signal supplied from the signal input unit 1, A scaling process corresponding to the number of pixels of the panel 7 is performed to generate an image signal for one frame. Further, the image memory for one frame is subjected to various image quality adjustments such as brightness, contrast, color density, hue, and sharpness based on the image quality adjustment signal output from the control unit 12, and then the frame memory. 4 is output.

  The timing control unit 3 generates a timing signal indicating one line period and a timing signal indicating one frame period based on the image signal supplied from the signal input unit 1, and supplies the timing signal to each unit of the liquid crystal display device 100. To do.

  The frame memory 4 stores the image signal input from the video processing unit 2 in units of frames.

  The calculation unit 5 calculates the amount of light necessary for each area S constituting the liquid crystal panel 7 based on the image signal input from the frame memory 4, and outputs the calculated amount of light in each area S to the control unit 12.

  Under the control of the control unit 12, the correction unit 6 outputs the image signals of the pixels belonging to each area S of the light source L corresponding to the area S so that each pixel area in the liquid crystal panel 7 emits light with a target light amount. Correct according to the amount of light.

The liquid crystal panel 7 is formed by sealing liquid crystal between a pair of substrates disposed at a predetermined interval. The pair of substrates is sandwiched between two polarizing plates whose polarization axes are orthogonal to each other, and a backlight 10 is disposed on the back side.
On the top surface of the substrate, p rows of scanning lines X (X _{1 to} X _p ) and q columns of signal lines Y (Y _{1 to} Y _q ) are arranged so as to be orthogonal to each other. The liquid crystal panel 7 employs, for example, an active matrix driving method, and a thin film transistor (TFT: thin film transistor) as an active element is disposed at each intersection pixel of the scanning line X and the signal line Y. . A pixel electrode is formed in each pixel, and a counter electrode is formed on the opposing substrate so as to face the pixel electrode. An alignment film is formed on the opposing surfaces of the pixel electrode and the counter electrode.

The scanning line driving unit 8 is provided corresponding to each of the scanning lines X (X _{1 to} X _p ) in the liquid crystal panel 7, and sequentially selects each scanning line X according to the timing signal from the timing control unit 3. Thus, the TFTs connected on the same scanning line X are turned on / off.
The signal line driving unit 9 is provided corresponding to each of the signal lines Y (Y _{1 to} Y _q ) in the liquid crystal panel 7, and in synchronization with scanning of each scanning line X by the scanning line driving unit 8, A voltage corresponding to the image signal input from the processing unit 2 is applied to the signal line Y.
When the scanning line X and the signal line Y are driven by the scanning line driving unit 8 and the signal line driving unit 9, the TFTs of the pixels at the intersections thereof are turned on, and charges are accumulated in the pixel electrodes. The alignment direction of the liquid crystal sandwiched between the counter electrode and the counter electrode changes, and the light irradiated from the backlight 10 provided on the back side of the liquid crystal panel 7 passes through the alignment film and the polarizing plate in units of pixels. Or block it.

  The backlight 10 is a direct type LED backlight provided on the back side of the liquid crystal panel 7, and houses an LED (not shown) inside a housing (not shown) opened on one side, and the opening of the housing The diffusion member 10a is attached to the part. The diffusion member 10a guides and disperses the light emitted from the LED.

In the present embodiment, the liquid crystal panel 7 is divided into a plurality of areas S.
In addition, the backlight 10 disposed on the back side of the liquid crystal panel 7 includes a plurality of light sources L that correspond one-to-one to a plurality of areas S constituting the liquid crystal panel 7.

Here, FIG. 2A is a diagram schematically showing a display area of the liquid crystal panel 7 of the present embodiment, and FIG. 2B is a diagram schematically showing the backlight 10 of the present embodiment. is there.
As shown in FIG. 2A, in the liquid crystal display device 100 of the present embodiment, the display area of the liquid crystal panel 7 is equally divided into a matrix of n vertical S × m horizontal S areas. . As shown in FIG. 2B, the backlight 10 is composed of n vertical light sources × m horizontal light sources L corresponding one-to-one to the area S constituting the liquid crystal panel 7.

In the following, n = 8 and m = 8, the liquid crystal panel 7 is divided into a total of 64 areas S of 8 vertical × 8 horizontal, and the backlight 10 has a total of 64 vertical 8 × 8 horizontal 64. A case where the light source L is divided into individual light sources L will be described.
Of the 64 areas S, S (1, 1) is located in the upper left corner, S (8, 1) is located in the upper right corner, and S (8, 1) is located in the lower left corner. 1, 8), an area located at the lower right end is assigned a code S (8, 8), and the other areas S are assigned the same code.
Of the 64 light sources L, the light source located at the upper left end corresponding to the area S (1, 1) is L (1, 1), and the upper right end corresponding to the area S (8, 1). L (8, 1) as the light source to be operated, L (1, 8) as the light source located at the lower left end corresponding to the area S (1, 8), and located at the lower right end corresponding to the area S (8, 8) L (8, 8) is attached to the light source to be used, and the other light sources L are assigned with the same method.
The correspondence between each area S and each light source L is stored in advance in a predetermined storage area.

  The backlight control unit 11 drives the LEDs provided in each light source L of the backlight 10 in accordance with instructions from the control unit 12 and performs control to cause each light source L to emit light.

  The control unit 12 includes, for example, a CPU (Central Processing Unit) 121, a RAM (Random Access Memory) 122, a light distribution storage unit 123, a ROM (Read Only Memory) 124, and the like.

  The CPU 121 executes various programs stored in the ROM 124 in accordance with input signals input from the respective units of the liquid crystal display device 100, and outputs output signals to the respective units based on the execution programs. Overall control of the operation of the apparatus 100 is performed.

  The RAM 122 includes a program storage area for developing various programs executed by the CPU 121, a data storage area for storing input data and processing results generated when these processing programs are executed, and is used as a work area for the CPU 121. It is done.

The light distribution storage unit 123 is configured by, for example, a nonvolatile memory, and stores a light distribution state at the time of light emission of each light source L configuring the backlight 10. Specifically, the area S irradiated with light and the amount of light when each light source L emits light are stored for each light source L.
For example, FIG. 3 shows an example of light distribution when the light source L (4, 4) corresponding to the area S (4, 4) emits light with a light amount of 100%. As shown in FIG. 3, the light from the light source L (4, 4) is dispersed by the diffusing member 10a of the backlight 10, and the corresponding area S (4, 4) is irradiated with a light amount of 40%. Also, areas S (3, 3), S (4, 3), S (5, 3), S (3, 4), S (5, 4) around the corresponding area S (4, 4), S (3, 5), S (4, 5), and S (5, 5) are irradiated with 5% light. Further, the surrounding area S (4, 2), S (2, 4), S (6, 4), S (4, 6) is irradiated with a 2% light amount, and the area S (2, 2) is irradiated. ), S (3, 2), S (5, 2), S (6, 2), S (2, 3), S (6, 3), S (2, 5), S (6, 5) , S (2,6), S (3,6), S (5,6), S (6,6) are irradiated with 1% light.
Thus, the light from the light source L is distributed and irradiated not only to the corresponding area S but also to the surrounding area S. Therefore, in order to realize the light amount of a certain area S, the light amount of each light source L constituting the backlight 10 is calculated based on the light distribution storage unit 123, and each light source L is calculated with the calculated light amount. It is necessary to emit light.

  The ROM 124 stores processing programs, data, and the like in advance. For example, the calculation program 124a as the calculation unit, the first determination program 124b as the first determination unit, the second determination program 124c as the second determination unit, and the back A backlight control program 124d as a light control means is stored.

  The calculation program 124a is a program for causing the CPU 121 to realize a function of calculating the amount of light necessary for each area based on the image signal. The CPU 121 configures a calculation unit together with the calculation unit 5 by executing the calculation program 124a.

  The first determination program 124b determines to the CPU 121 the light amount determination order of the light source L so that the maximum light amount is in ascending order from the area S based on the light amount required for each area calculated in the execution of the calculation program 124a. It is a program for realizing the function to perform. The CPU 121 configures a first determination unit by executing the first determination program 124b.

  The second determination program 124c causes the CPU 121 to calculate the light amount of each light source L and the light amounts of the light sources L around the light source L based on the light amount required for each area calculated in the execution of the calculation program 124a. This is a program for realizing the function of determining in the light amount determination order determined by the first determination program 124b. The CPU 121 configures a second determination unit by executing the second determination program 124c.

  The backlight control program 124d is a program for causing the CPU 121 to realize a function of performing control for causing each of the light sources L to emit light with the light amount determined in the execution of the second determination program 124c. The CPU 121 configures a backlight control unit together with the backlight control unit 11 by executing the backlight control program 124d.

  Here, referring to the flowchart of FIG. 4, the above-described calculation program 124a, first determination program 124b, second determination program 124c, and backlight control program 124d are executed in the liquid crystal display device 100 of the present embodiment. The light emission control process of the light source L will be described.

  First, in step S1, the CPU 121 calculates the amount of light necessary for each area S in the calculation unit 5 based on the image signal.

  FIG. 5 shows an example of the required light amount of each area S calculated based on the image signal. In FIG. 5, for example, the required light amount of area S (1, 1) is “65”, the required light amount of area S (5, 2) is “84”, and the required light amount of area S (3, 3) is “78”. It is said that. The area S (3, 4) is the area S having the maximum necessary light amount “87”, and the area S (7, 6) is the area S having the minimum necessary light amount “27”.

  Next, in step S <b> 2, the CPU 121 determines the light amount determination order for determining the light amount of the light source L so that the light amount of the corresponding area S is ascending from the maximum area S. The order of determining the light quantity from the area S with the maximum light quantity is as follows: the light source L corresponding to the area S with the largest necessary light quantity is first, and the light source L corresponding to the area S with the smallest necessary light quantity is last. By determining the light amount of each light source L in this order, the light amount of the light source L can be determined in order from the area S where the required light amount is large.

  FIG. 6 shows a light amount determination order determined based on the required light amount of each area S illustrated in FIG. In FIG. 6, for example, the light quantity determination order of the light sources L (3, 4) corresponding to the area S (3, 4) having the maximum required light quantity is the first. The light quantity determination order of the light sources L (7, 6) corresponding to the area S (7, 6) with the minimum required light quantity is 64th.

  Next, in step S3, the CPU 121 determines the light amount of each light source L in the light amount determination order determined in step S2.

Specifically, first, the CPU 121 targets the area S (3, 4) having the first light quantity determination order (see FIG. 7), and the light quantity “87” required for the area S (3, 4). The light quantity of each light source L for irradiating is determined. FIG. 8 shows the light amount of each light source L for irradiating the area S (3, 4) with the light amount “87”.
Next, the CPU 121 targets each area S (5, 2) whose light quantity determination order is the second (see FIG. 9), and each light source for irradiating the area S (5, 2) with the necessary light quantity “84”. The L light quantity is determined to be added to the already determined light quantity. FIG. 10 shows the light amount of each light source L for irradiating the area S (3, 4) with the light amount “87” and irradiating the area S (5, 2) with “84”.
Further, the CPU 121 determines the light amount of the light source L for irradiating all the areas S with the necessary light amount by performing the above-described process for each of the areas S in the light amount determination order 3rd to 64th.

Here, FIG. 11 shows the light amount of each light source L for realizing the light amount of FIG. 12 shows the light quantity of each light source L in the order in which the light sources L are arranged (for example, L (1,1), L (1,2)... L (2,1)... L ( 8 and 8)) are the light amounts of the respective light sources L for realizing the light amount of FIG. 5 calculated using the conventional method.
As in the present invention, in the method of determining the light amount of the light source L in the order of the required light amount of the corresponding area S, when determining the light amount of the area S where the required light amount is small, the required light amount is influenced by the surrounding area S. Can be suppressed. Therefore, the light amount of 5.4% can be reduced in the entire backlight 10 as compared with the conventional example of FIG. 12 using the conventional method.

  Next, in step S4, the CPU 121 causes the backlight control unit 11 to emit light of each light source L with the light amount of each light source L determined in step S3, and ends this processing.

According to the liquid crystal display device 100 of the present embodiment described above, the light amount necessary for each area is calculated based on the image signal by the execution of the calculation program 124a by the CPU 121, and is calculated by the execution of the first determination program 124b. Based on the amount of light necessary for each area calculated by executing the program 124a, the light amount determination order of the light source L is determined so as to increase from the area S of the maximum light amount, and by executing the second determination program 124c, The light quantity determination in which the light quantity of each light source L and the light quantity of the light source L around the light source L are determined by the first determining means based on the light quantity required for each area calculated by executing the calculation program 124a. Each of the light sources L is determined by the second determining means by executing the backlight control program 124d. Control to emit light in an amount is performed.
That is, based on the light quantity required for each area S, the light quantity determination order is determined so as to be the ascending order from the area S of the maximum light quantity, and the light quantity of each light source L is determined in the determined light quantity determination order. Become. Therefore, in the liquid crystal display device 100 in which the display area is divided into a plurality of areas S, the light amount of each light source L is determined in order from the area S with the highest light amount, thereby reducing the light amount of the entire backlight. The light emission control of the light sources L can be performed more efficiently than when the light amounts of the light sources L are simply determined in the order in which they are arranged.

  Further, since the diffusing member 10a for diffusing the light emitted from each light source L of the backlight 10 is disposed on the front surface of the backlight 10, display unevenness in the liquid crystal panel 7 is prevented and the luminance is improved. be able to.

The scope of the present invention is not limited to the above embodiment, and various improvements and design changes may be made without departing from the spirit of the present invention.
For example, the division mode of the area S in the liquid crystal panel 7 is arbitrary, and may not be, for example, equal division.
In addition to means for determining the light quantity of each light source L in ascending order from the area S with the maximum light quantity, the light source L includes means for determining the light quantity of each light source L in the order in which the light sources L are arranged. You may comprise so that it may switch.

  The present invention can be used in the manufacturing industry of liquid crystal display devices.

100 Liquid crystal display device 5 Calculation unit (calculation means)
7 Liquid crystal panel 10 Backlight 11 Backlight control unit (backlight control means)
121 CPU (calculation means, first determination means, second determination means, backlight control means)
124a Calculation program (calculation means)
124b First determination program (first determination means)
124c Second determination program (second determination means)
124d Backlight control program (backlight control means)

Claims (2)

In a liquid crystal display device comprising a liquid crystal panel divided into a plurality of areas, and a backlight comprising a plurality of light sources corresponding one-to-one to the areas,
A calculation means for calculating a necessary light amount for each area based on an image signal;
First determining means for determining the light quantity determination order of the light source based on the light quantity required for each area calculated by the calculating means so as to be in ascending order from the area of the maximum light quantity;
Based on the amount of light necessary for each area calculated by the calculation means, the light amount of each light source and the light amounts of light sources around the light source are determined in the light amount determination order determined by the first determination unit. Second determining means for determining;
Backlight control means for controlling each of the light sources to emit light with the light amount determined by the second determination means;
A liquid crystal display device comprising: In a liquid crystal display device comprising a liquid crystal panel divided into a plurality of areas, and a backlight comprising a plurality of light sources corresponding one-to-one to the areas,
A calculation means for calculating a necessary light amount for each area based on an image signal;
First determining means for determining the light quantity determination order of the light source based on the light quantity required for each area calculated by the calculating means so as to be in ascending order from the area of the maximum light quantity;
Based on the amount of light necessary for each area calculated by the calculation means, the light amount of each light source and the light amounts of light sources around the light source are determined in the light amount determination order determined by the first determination unit. Second determining means for determining;
Backlight control means for controlling each of the light sources to emit light with the light amount determined by the second determination means;
With
A liquid crystal display device, wherein a diffusion member for diffusing light emitted from each light source of the backlight is disposed on the front surface of the backlight.

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