JP2008116555A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display device which prevents an apparent OSD image from appearing different so much and can reduce the unnaturalness. <P>SOLUTION: The liquid crystal display device is provided with: a tuner part 1; a signal processing part 2; a display part 3; and a CPU 4. An image signal is input into the tuner part 1. The signal processing part 2 processes the video signal from the tuner part 1. The display part 3 displays a video of broadcast processed by the signal processing part 2. The CPU 4 changes the brightness of a backlight of the display part 3 in accordance with a displayed scene. The CPU 4 changes an OSD color so as to compensate a fluctuation of brightness of the backlight. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a liquid crystal display device that changes an OSD (On Screen Display) color of a liquid crystal television in conjunction with the brightness of a backlight.

  Conventionally, there is a technique for changing the backlight brightness of a liquid crystal television in conjunction with the scene.

  However, there is no example of controlling the OSD display color according to the brightness fluctuation of the backlight of the liquid crystal television.

FIG. 6 is an explanatory diagram showing a method for controlling the backlight brightness of a conventional liquid crystal television.
As shown in FIG. 6, the conventional method for controlling the brightness of the backlight of the liquid crystal television is that the television determines the brightness of the backlight BL according to the scene, controls the brightness of the backlight BL, and the OSD data. Is superimposed on the video signal and displayed on the TV screen 9 by OSD.

Conventionally, Patent Document 1 proposes an image display device that changes the brightness of the OSD display in accordance with the light emission brightness of the backlight.
JP-A-2005-321423

  However, in the method of controlling the backlight brightness of the conventional liquid crystal television shown in FIG. 6, if the brightness of the backlight BL is changed in conjunction with the scene, the image is displayed appropriately, but this is not related to it. Since the OSD display is also affected, the apparent brightness of the OSD display changes.

  Conventionally, there is a technology for actively controlling the brightness of the backlight of the liquid crystal television in conjunction with the displayed image, but the brightness of the OSD color also varies according to the brightness of the backlight. There is a problem.

  When the brightness of the backlight fluctuates, we want to change the OSD color in conjunction with it so that the appearance of the OSD does not change so much.

  Furthermore, when the user adjusts the brightness of the backlight, the appearance of the OSD should also change, so it is desirable to link the OSD color in cases other than user adjustment.

  Therefore, the present invention has been made in view of the above circumstances, and by changing the OSD color when the brightness of the backlight linked to the image is changed, the appearance of the OSD does not change so much. Therefore, an object is to provide a liquid crystal display device capable of reducing unnaturalness.

  In order to solve the problems of the prior art, a liquid crystal display device of the present invention displays a video input unit, a signal processing unit that processes a video signal from the video input unit, and a video processed by the signal processing unit. And a control means for changing the brightness of the backlight of the display unit in accordance with the scene to be displayed, and a liquid crystal display device for OSD display superimposed on the video signal, wherein the control means The OSD color is changed so as to cancel out the brightness variation of the backlight.

  In the liquid crystal display device of the present invention, when the control means is an OSD display using a CLUT (Color Look Up Table), the OSD color displayed in the OSD display is changed by changing the color registered in the CLUT. It is supposed to change.

  In the liquid crystal display device of the present invention, when the control means is an OSD display that does not use a CLUT, the OSD is redrawn every time the color is changed.

  In the liquid crystal display device of the present invention, the control means calculates the color value to be changed from the original color value and the brightness value of the backlight when the change is executed.

  In the liquid crystal display device of the present invention, the control means prepares an array calculated in advance in the program and refers to the color value to be changed.

  In the liquid crystal display device of the present invention, the control means changes the original OSD color to a color obtained by increasing RGB, thereby increasing the brightness of the OSD color so as to cancel out the darkening of the white backlight. It is like that.

  The liquid crystal display device of the present invention darkens the brightness of the OSD color so that the control unit changes the original OSD color to a color obtained by subtracting RGB from each other to cancel the brightening of the white backlight. It is like that.

  In the liquid crystal display device of the present invention, when the control means is interlocked with the brightness of the backlight that is not white, the liquid crystal display device is configured to increase or decrease with a corresponding bias in RGB.

  The liquid crystal display device of the present invention includes brightness detection means for detecting the brightness around the display unit, and the control means performs a back operation according to the brightness around the display unit detected by the brightness detection means. The brightness of the light is changed, and the OSD color is changed in an unlinked manner with the brightness of the backlight.

  In the liquid crystal display device of the present invention, the control means changes the OSD color in a manner not interlocked with the brightness of the backlight adjusted by the user.

  The liquid crystal display device of the present invention is a television with a built-in tuner that employs a tuner that selects a broadcast channel received by an antenna as the video input unit.

  The liquid crystal display device of the present invention is a video monitor in which the video input unit receives and displays a video signal from an external video signal source.

  As described above, according to the present invention, by changing the OSD color when the brightness of the backlight linked to the image is changed, the appearance of the OSD is changed so as not to be seen. A liquid crystal display device that can be reduced can be obtained.

  Hereinafter, a liquid crystal display device of the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  The liquid crystal display device of the present invention includes a tuner unit 1 that is a video input unit, a signal processing unit 2 that processes a video signal from the tuner unit 1, a display unit 3 that displays a video processed by the signal processing unit 2, A CPU (Central Processing Unit) 4 serving as control means for changing the brightness of the backlight of the display unit 3 in accordance with the scene to be displayed is provided.

  The liquid crystal display device of the present invention is an OSD display device superimposed on a video signal.

  In the liquid crystal display device of the present invention, the CPU 4 changes the OSD color so as to cancel out the brightness variation of the backlight.

  In the liquid crystal display device of the present invention, when the CPU 4 performs OSD display using CLUT, the OSD color displayed in the OSD is changed by changing the color registered in the CLUT.

  In the liquid crystal display device of the present invention, when the CPU 4 performs OSD display without using a CLUT, the OSD is redrawn every time the color is changed.

  In the liquid crystal display device of the present invention, the CPU 4 calculates the color value to be changed from the original color value and the brightness value of the backlight when the change is executed.

  In the liquid crystal display device of the present invention, the CPU 4 refers to the color value to be changed by preparing a previously calculated arrangement in the program.

  In the liquid crystal display device of the present invention, the brightness of the OSD color is increased so that the CPU 4 changes the original OSD color to a color obtained by increasing RGB, thereby canceling the darkening of the white backlight. It has become.

  In the liquid crystal display device of the present invention, the brightness of the OSD color is reduced so that the CPU 4 changes the original OSD color to a color obtained by subtracting RGB from each other so as to cancel the brightening of the white backlight. It has become.

  In the liquid crystal display device of the present invention, when the CPU 4 is interlocked with the brightness of the backlight that is not white, it increases or decreases with a corresponding bias in RGB.

  The liquid crystal display device of the present invention includes a brightness sensor 5 which is a brightness detection means for detecting the brightness around the display unit 3.

  In the liquid crystal display device of the present invention, the CPU 4 changes the brightness of the backlight according to the ambient brightness of the display unit 3 detected by the brightness sensor 5, and the OSD color is not linked to the brightness of the backlight. Is supposed to change.

  In the liquid crystal display device of the present invention, the CPU 4 changes the OSD color in a manner not interlocked with the brightness of the backlight adjusted by the user.

  The liquid crystal display device of the present invention is a television with a built-in tuner that employs a tuner that selects a broadcast channel received by an antenna as a video input unit.

  The liquid crystal display device of the present invention is a video monitor in which a video input unit receives and displays a video signal from an external video signal source.

FIG. 1 is a block diagram showing an example of the configuration of a liquid crystal display device according to an embodiment of the present invention.
An example of the liquid crystal display device of the present invention will be described with reference to FIG.
As shown in FIG. 1, the liquid crystal display device includes a tuner unit 1, a signal processing unit 2, a display unit 3, a CPU 4, a brightness sensor 5, a nonvolatile memory 6, a work memory 7, and an input device. 8 and.

  The tuner unit 1 selects a channel for digital broadcasting received by an antenna (not shown).

  The signal processing unit 2 processes the video signal of the digital broadcast channel selected by the tuner unit 1 to obtain the brightness of the scene.

  The display unit 3 displays the digital broadcast video processed by the signal processing unit 2.

  The CPU 4 controls the entire apparatus, and changes the brightness of the backlight of the display unit 3 according to the scene to be displayed.

  The brightness sensor 5 obtains the brightness around the display unit 3 of the liquid crystal television.

  The non-volatile memory 6 stores a control program of the CPU 4 and a CLUT which is a correspondence table of color numbers and RGB formats, and stores a user setting value of backlight brightness.

  The work memory 7 is for recording and reading various data during operation of the apparatus, and temporarily stores the received digital broadcast program information.

  The input device 8 allows the user to set the backlight brightness using a menu or the like.

There are the following cases for the control to change the brightness of the backlight.
(1) The case where the LCD TV changes frequently according to the scene to be displayed (2) The case where the LCD TV changes according to the brightness of the surroundings of the LCD TV (3) The user uses the menu etc. Case for adjusting brightness

  (1) In the case where the liquid crystal television frequently changes in accordance with the scene to be displayed and the OSD is not involved in the determination of determining the backlight brightness, the liquid crystal television sets the backlight brightness according to the video. Because of the fluctuation, the brightness variation of the backlight is natural and unnoticeable in the video portion, whereas the brightness variation of the backlight becomes unnaturally conspicuous in the OSD portion affected by the wrapping.

  When the backlight is darkened as a control of the liquid crystal television, if the brightness of the OSD color is changed so as to cancel out the brightness variation of the backlight, such as brightening the OSD color, a certain amount of backlight brightness fluctuation occurs. Within this range, the brightness variation of the OSD portion does not appear unnatural to the user.

  In order to change the displayed OSD color, if the OSD display system uses a CLUT, the color registered in the CLUT may be changed.

  If the OSD display system does not use the CLUT, the OSD may be redrawn every time the color is changed.

  The color value to be changed may be obtained by calculation at the time of execution of the change from the original color value and the backlight brightness value, or a pre-calculated array may be prepared in the program for reference. good.

  In order to brighten the brightness of the OSD color so as to cancel out the darkening of the white backlight, the original OSD color is changed to a color obtained by increasing RGB.

  In order to darken the brightness of the OSD color so as to cancel the brightening of the white backlight, the original OSD color is changed to a color obtained by subtracting each of RGB.

  When interlocking with the brightness of the non-white backlight, the RGB is increased or decreased with a corresponding bias.

Furthermore, when changing the brightness of the OSD color so as to offset the fluctuation of the brightness of the backlight, there may be a case where the change in only the brightness does not work due to the optical characteristics of the backlight.
For example, when interlocking with brightness such as a hybrid backlight of a white fluorescent tube and a red LED, the RGB is increased or decreased with a corresponding bias.

FIG. 2 is an explanatory diagram illustrating a method of controlling the brightness of the backlight in a case where the frequency is frequently changed according to a scene displayed on the liquid crystal television.
When the brightness of the backlight BL is linked to the video, the signal processing unit 2 obtains the brightness of the scene, and the television determines the brightness of the backlight BL according to the scene and controls the brightness of the backlight BL.

  Further, the television changes the OSD color using the CLUT so as to cancel the brightness variation of the backlight BL, and the OSD data is superimposed on the video signal and displayed on the television screen 9 as an OSD.

  By the way, in the case (2) where the liquid crystal television changes according to the brightness of the surroundings of the liquid crystal television and the case (3) where the user adjusts the brightness of the backlight using a menu or the like, There is no need to synchronize the brightness.

For example, in the case (2) where the liquid crystal television is changed according to the brightness around the liquid crystal television, the backlight is darkened because the surroundings of the liquid crystal television are dark.
At that time, if the brightness of the OSD color is increased so that the OSD display looks as it is, the OSD is dazzled as a result.

Alternatively, since the periphery of the liquid crystal television is bright, control is performed to brighten the backlight.
At that time, if the brightness of the OSD color is lowered so that the OSD display looks as it is, the OSD becomes dark as a result.

  After all, in the case of (2) above, OSD color interlocking control should not be performed.

  For example, in the case (3) where the user adjusts the brightness of the backlight using a menu or the like, the OSD display appears to remain unchanged even though the backlight is adjusted to a brightness that is easy for the user to see. Is dazzling or dark.

  Eventually, in the case of (3), the OSD color interlocking control should not be performed.

  That is, when the brightness of the backlight fluctuates depending on the combination of (1), (2), and (3) above, the OSD color is used for the backlight brightness fluctuation due to (2) and (3). A natural control method is to use only the brightness fluctuation of the backlight due to (1) as a reference value for linking OSD colors without linking them.

  Furthermore, it is necessary to cancel the OSD color change to compensate for backlight fluctuations linked to the scene. However, backlight brightness fluctuations due to the brightness around the TV and backlight brightness fluctuations caused by user operations Therefore, it is necessary to follow the OSD color as it is.

FIG. 3 is an explanatory diagram illustrating a method of controlling the brightness of the backlight in a case where the liquid crystal television changes according to the brightness of the surroundings of the liquid crystal television and a case where the user adjusts the brightness of the backlight using a menu or the like. It is.
When the user adjusts the brightness of the backlight BL using the user menu 10, the user determines the brightness of the backlight BL and obtains the basic backlight brightness (A) from the user settings.

  When the brightness of the backlight BL is synchronized with the ambient brightness of the television, the brightness sensor 5 obtains the ambient brightness of the television, and the television determines the brightness of the backlight BL according to the ambient brightness of the television. The amount of change (B) is determined based on the brightness around the television and the brightness (A) of the backlight BL.

  When the brightness of the backlight BL is linked to the video, the signal processing unit 2 determines the brightness of the scene, and the television determines the brightness of the backlight BL according to the scene, and the brightness of the video scene and the backlight brightness. The amount of change (C) is obtained based on the amount of change (A) and the amount of change (B).

  The brightness of the backlight BL is obtained as (A) + (B) + (C) by the adder 11, and the brightness of the backlight BL is controlled.

  Furthermore, the OSD color is changed using the CLUT so that only the brightness fluctuation of the backlight BL due to the scene is canceled, and the OSD data is superimposed on the video signal and displayed on the television screen 9 as OSD.

  In a liquid crystal television that performs backlight brightness control in conjunction with a scene, the OSD color superimposed on the television screen is appropriately changed to a color that cancels the brightness fluctuation of the scene interlocking backlight. It can prevent the color from changing.

FIG. 4 is a diagram illustrating an example of a CLUT used when the user adjusts the brightness of the backlight.
FIG. 4 shows an example of a 256 color CLUT used when the user adjusts the brightness of the backlight using a menu or the like.
For example, the non-volatile memory 6 stores a 256 color CLUT 12 as shown in FIG.

  The CLUT 12 for 256 colors shown in FIG. 4 has red (R), green (G), and blue (B) as 0 (dark) to 255 (bright), respectively, and the brightness of the color is changed when the backlight brightness becomes bright. Drop it.

  Since it is a CLUT, what color is assigned to the color number depends on the program, so the above is an example of the CLUT.

FIG. 5 is a control flowchart for controlling the brightness of the backlight in the liquid crystal display device according to the embodiment of the present invention.
First, the basic backlight brightness (A) is obtained from the user settings (step S100).

  Next, when the brightness of the backlight is linked to the brightness around the television, the change amount (B) is obtained based on the brightness around the television and the brightness (A) of the backlight (step S101).

  Next, when the brightness of the backlight is linked to the video, the change amount (C) is obtained based on the brightness of the video scene, the brightness of the backlight (A), and the change amount (B) (step S102). .

  Next, the brightness of the backlight is obtained as (A) + (B) + (C), and the brightness of the backlight is controlled (step S103).

  Next, the OSD color is changed by the value of the change amount (C) (step S104).

  Thereafter, the process returns to step S101 and is rotated at the timing of controlling the backlight.

Conventionally, a television has not been very particular about how the OSD is seen, but since it has become a digital television and the number of OSD displays has increased dramatically, the appearance of the OSD becomes important.
In the present invention, the OSD color is also changed in conjunction with the backlight control unique to the liquid crystal television.

  Although the above has been described based on a liquid crystal television with a built-in tuner, the present invention displays a video signal from a set top box, a DVD player, or an HDD recorder connected by a cable such as a video cable, an S video cable, or an HDMI cable. Needless to say, it is used for a so-called “video monitor”, a liquid crystal display for displaying a video signal from an external personal computer connected by a display cable.

  According to the present invention, the OSD color is determined using only the amount of backlight brightness fluctuation linked to the image, and the amount of backlight brightness fluctuation due to user settings and the brightness around the television is not used. , OSD color unnatural changes can be reduced.

1 is a block diagram illustrating an example of a configuration of a liquid crystal display device according to an embodiment of the present invention. Explanatory drawing which shows the method of controlling the brightness of the backlight in the case where it changes frequently according to the scene which a liquid crystal television displays. Explanatory drawing which shows the method to control the brightness of a backlight in the case where a liquid crystal television changes according to the surrounding brightness of a liquid crystal television, and a user adjusts the brightness of a backlight with a menu etc. The figure which shows an example of CLUT used when a user adjusts the brightness of a backlight. The control flow figure which controls the brightness of the backlight in the liquid crystal display device concerning the example of the present invention. Explanatory drawing which shows the method of controlling the brightness of the backlight of the conventional liquid crystal television.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tuner part 2 Signal processing part 3 Display part 4 CPU (control means)
5 Brightness sensor (brightness detection means)
6 Nonvolatile Memory 7 Work Memory 8 Input Device 9 TV Screen 10 User Menu 11 Adder 12 256 Color CLUT
BL backlight

Claims (12)

A video input unit; a signal processing unit that processes a video signal from the video input unit; a display unit that displays the video processed by the signal processing unit; and brightness of a backlight of the display unit according to a scene to be displayed A liquid crystal display device that performs OSD display by superimposing it on a video signal.
The liquid crystal display device, wherein the control means changes the OSD color so as to cancel out the brightness variation of the backlight.   2. The liquid crystal display device according to claim 1, wherein when the OSD display uses a CLUT, the control unit changes the OSD color displayed in the OSD by changing a color registered in the CLUT.   2. The liquid crystal display device according to claim 1, wherein, when the OSD display does not use a CLUT, the control unit redraws the OSD every time the color is changed.   The liquid crystal display device according to claim 1, wherein the control means obtains the color value to be changed from the original color value and the backlight brightness value by calculation when the change is executed.   The liquid crystal display device according to claim 1, wherein the control means prepares an array calculated in advance in a program and refers to a color value to be changed.   2. The liquid crystal display according to claim 1, wherein the control means changes the brightness of the OSD color so as to cancel the darkening of the white backlight by changing the original OSD color to a color obtained by increasing RGB. apparatus.   The liquid crystal display according to claim 1, wherein the control means changes the brightness of the OSD color so as to cancel the brightening of the white backlight by changing the original OSD color to a color obtained by subtracting each of RGB. apparatus.   2. The liquid crystal display device according to claim 1, wherein the control means increases or decreases with a corresponding bias in RGB when interlocking with the brightness of a non-white backlight.   Brightness detection means for detecting the brightness around the display section, the control means changes the brightness of the backlight according to the brightness around the display section detected by the brightness detection means, The liquid crystal display device according to claim 1, wherein the OSD color is changed in association with the brightness of the backlight.   The liquid crystal display device according to claim 1, wherein the control unit changes the OSD color in a manner not interlocked with the brightness of the backlight adjusted by the user.   The liquid crystal display device according to claim 1, wherein the video input unit is a tuner built-in television that employs a tuner that selects a broadcast channel received by an antenna.   The liquid crystal display device according to claim 1, wherein the video input unit is a video monitor that receives and displays a video signal from an external video signal source.

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