JP2008116554A - Backlight control device and video display device equipped with the backlight control device - Google Patents

Backlight control device and video display device equipped with the backlight control device Download PDF

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JP2008116554A
JP2008116554A JP2006297865A JP2006297865A JP2008116554A JP 2008116554 A JP2008116554 A JP 2008116554A JP 2006297865 A JP2006297865 A JP 2006297865A JP 2006297865 A JP2006297865 A JP 2006297865A JP 2008116554 A JP2008116554 A JP 2008116554A
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mask pattern
mask
non
portion
display screen
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JP2006297865A
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Hiroyuki Takano
裕之 高野
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Sharp Corp
シャープ株式会社
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Abstract

<P>PROBLEM TO BE SOLVED: To control light emission, by quickly specifying a portion where turning on a backlight light source is unnecessary, regardless of the shape of a non-picture portion displayed on a display screen. <P>SOLUTION: The video display device acquires (S1) image data of video signals to be displayed and computes (S2) with a stored n-th mask pattern. After computation, the device discriminates (S3) whether the mask portion of the n-th mask pattern coincides with the non-picture portion on the display screen; and if they coincide, the device controls (S4) so as to turn on the backlight light source according to the mask pattern. The light source corresponding to the mask portion will not turned be on, while the light source corresponding to the non-mask portion is turned on. If the mask portion of the mask pattern does not coincide with the non-picture portion of the display screen in the step S3, the device discriminates (S5) whether another mask pattern is present. If another mask pattern is not present, the device turns on (S6) the whole backlight light source; but if another mask pattern is present, the device updates (S7), by replacing n by n+1 and returns to the step S2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a backlight control device and a video display device including the device, and more particularly, a backlight control device for controlling a backlight light source for illuminating a liquid crystal display panel from the back, and the same The present invention relates to a video display device including a backlight control device.

  In order to display a video source, a video display device including a matrix type display panel such as a liquid crystal display panel is generally used. In a display device using a liquid crystal display panel, a backlight light source for illuminating the liquid crystal display panel from the back and modulating the illumination light with the liquid crystal display panel to display an image is used.

Video sources displayed on the video display device include, for example, NTSC broadcast video with an aspect ratio of 4: 3, HDTV broadcast video with an aspect ratio of 16: 9, and the like. In movies and the like, a video signal having a horizontally longer aspect ratio than 4: 3, which is called a cinema type, is used.
Also on the display screen of the video display device, a display panel having a pixel aspect ratio of 4: 3, a display panel having an aspect ratio of 16: 9 corresponding to high vision, and the like are used.

Thus, there are a plurality of standards for the aspect ratio of the video source, and there are also a plurality of standards for the aspect ratio of the display screen of the video display device that displays the video source.
FIG. 15 is a diagram schematically showing a display example of a letterbox video signal.
For example, when a video signal having an aspect ratio of 16: 9 is to be displayed using a display panel having an aspect ratio of 4: 3, a display form called a letterbox method is used. In letterbox display, a no-image portion 112 without an image is provided in a horizontal direction at the upper and lower ends of a display panel having an aspect ratio of 4: 3. The video unit 111 having an aspect ratio of 16: 9 is displayed.

  The letterbox broadcast signal is broadcast in a state where the above-mentioned non-image portion 112 is added to the video portion 111 on the broadcast station side. When a letterbox broadcast signal is displayed on a 16: 9 display panel, only the video unit 111 can be displayed without displaying the non-image unit 112.

  FIG. 16 is a diagram schematically illustrating a display example of a side panel video signal. For example, when a video signal having an aspect ratio of 4: 3 is to be displayed on a display panel having an aspect ratio of 16: 9, a display form called a side panel method is used. In the side panel display, a non-image portion 112 having no image is provided in the vertical direction at the left and right end portions of a display panel having an aspect ratio of 16: 9, and between the left and right non-image portions 112. The video unit 111 having an aspect ratio of 4: 3 is displayed. In these examples, the obi-shaped no-image portion 112 is called black obi.

Alternatively, some video display devices have a function of switching the display screen size of a video signal (for example, called an auto-wide function). When dealing with such a function of switching the size, it is necessary to change the enlargement ratio of the video signal in accordance with the aspect ratio of the display panel.
For example, in the normal mode of FIG. 17, when a video signal having an aspect ratio of 4: 3 is displayed on a display panel having an aspect ratio of 16: 9, the video signal is scaled and displayed as an image having the same aspect ratio. Further, an obi-shaped no-image portion 112 is added to the left and right of the video for display.

In the cinema mode shown in FIG. 18, the portion excluding the non-image portion 112 from the letterbox type or cinema-type 4: 3 video signal having the obi-shaped non-image portion 112 at the upper and lower ends is left as it is. The image is scaled and displayed in the aspect (16: 9).
As described above, even when the display screen size of the video signal is changed in the video display device, the above-described non-image portion may be generated depending on the video signal method and the screen display mode at that time.

  Alternatively, for example, when the screen is divided using the two-screen display function of the video display device, the video source is displayed on one split screen, and the other split screen is not displayed, such a non-image portion is also displayed. Occurs. At this time, there may be a case where a non-image portion is further generated in the divided screen by displaying a video signal of a different aspect or changing the display mode on one divided screen.

That is, as described above, it is necessary to display a non-image portion on the display panel of the video display device according to the combination of the video signal system, the specification of the video display device, the image display mode, and the like. Also, various shapes are taken according to the above conditions.
In this case, in an image display device using a backlight light source, if the illumination light from the backlight light source is irradiated also to the non-image portion as described above, the illumination light is also applied to a region that originally does not have an image (no image is displayed). Becomes inefficient from the viewpoint of reducing the power consumption of the backlight light source.

Regarding such a problem, for example, in Patent Document 1, when an image having an aspect ratio different from the aspect ratio of the screen of the liquid crystal display panel is displayed, the backlight light source is automatically turned on for the non-image area display area. Disclosed is a liquid crystal display device in which wasteful power consumption is reduced by stopping automatically. This liquid crystal display device displays an image by irradiating the liquid crystal display panel using a backlight light source having a plurality of light emitting areas, detects an imageless portion of an input video signal, and detects no image in the liquid crystal display panel. The image area display area is determined, and the light emission area of the backlight source corresponding to the non-image area display area is controlled to be turned off.
JP 2004-184937 A

  As described above, the display panel of a video display device is subject to conditions such as display panel specifications such as panel size and resolution, video source type (analog wave, digital wave, input terminal system, etc.), or video display mode. Accordingly, a display area of the non-image area is generated, and the shape of the non-image area at this time can take various shapes. The time required to detect these non-image areas also differs depending on each condition.

In the liquid crystal display device of Patent Document 1, when the aspect ratio of the input video signal is different from the aspect ratio of the screen of the display panel, the light emitting area of the backlight light source corresponding to the non-image area is turned off, which is useless. The power consumption can be reduced.
However, as described above, the shape of the non-image portion can take various shapes not only when the aspect ratio is different, but also depending on the video source method, display panel specifications, video display mode on the display panel, and the like.
Even when such non-image areas of various shapes are generated, the power consumption is reduced by reliably detecting the non-image areas and controlling the light emission of the backlight light source according to the non-image areas. The energy saving effect by can be realized more effectively.

  The present invention has been made in view of the above-described circumstances, and when displaying a video signal, a portion that does not require lighting of the backlight light source can be quickly displayed regardless of the shape of the non-image portion displayed on the display screen. An object of the present invention is to provide a backlight control device capable of more effectively realizing an energy saving effect by reducing power consumption by performing light emission control specifically, and an image display device including the device. is there.

  In order to solve the above problems, a first technical means of the present invention is a backlight control device that controls a backlight light source for illuminating a liquid crystal display panel that displays an image based on an input video signal. , Whether the shape of the non-image portion of the display screen of the video signal to be displayed matches the mask portion of the mask pattern, and storage means for storing a plurality of mask patterns that prescribe the non-lighting area of the backlight light source as a mask portion And a backlight control means for controlling the lighting pattern of the backlight light source based on the mask pattern determined by the determining means to match the shape of the non-image portion of the display screen. It is a feature.

  The second technical means is characterized in that, in the first technical means, the backlight control means performs control to turn off the backlight light source at the position corresponding to the mask portion of the mask pattern.

  A third technical means is a plurality of mask patterns having a mask portion in the first or second technical means having a mask portion that matches a shape of a non-image portion that can be taken when displaying an image based on a video signal. It is characterized by that.

  According to a fourth technical means, in the third technical means, the judging means determines whether or not the mask portion of the mask pattern matches the shape of the non-image portion of the display screen for a plurality of mask patterns stored in the storage means. If there is a mask pattern having a mask portion that matches the shape of the non-image portion of the display screen, the backlight control means controls the lighting pattern of the backlight light source based on the mask pattern, and the non-image portion If there is no mask pattern having a mask portion that matches the shape, the control is performed to turn on all the backlight light sources.

  According to a fifth technical means, in any one of the first to fourth technical means, the judging means sets the image data of each pixel at a position corresponding to the pixel on the display screen in the mask pattern, and the pixel on the display screen The image data of the mask pattern and the image data of the pixel of the mask pattern at the position corresponding to the pixel of the image data are calculated, and whether the mask portion of the mask pattern and the shape of the non-image portion of the display screen match according to the calculation result It is characterized by judging.

  The sixth technical means is characterized in that, in the fifth technical means, the judging means calculates the image data of the pixels of the display screen for the image data of all the pixels of the mask pattern.

  The seventh technical means is characterized in that, in the fifth technical means, the judging means calculates only the image data of the pixels of the mask portion of the mask pattern with the image data of the pixels of the display screen.

  An eighth technical means is the fifth technical means, characterized in that the operation is an OR operation of the pixel data of the pixels of the mask pattern and the pixel data of the pixels of the display screen.

  According to a ninth technical means, in the fifth technical means, the calculation is a calculation for comparing pixel data of a pixel of a mask pattern and pixel data of a pixel of a display screen.

  According to a tenth technical means, in the fifth technical means, the calculation is a subtraction of pixel data of a pixel of a mask pattern and pixel data of a pixel of a display screen.

  The eleventh technical means is the fifth technical means characterized in that the calculation is an XOR operation of pixel data of a pixel of a mask pattern and pixel data of a pixel of a display screen.

  A twelfth technical means includes a backlight control device according to any one of the first to eleventh technical means, a backlight light source controlled by the backlight control device, and a liquid crystal display panel illuminated by the backlight light source. And a video signal image is displayed on a liquid crystal display panel.

  According to the present invention, when displaying a video signal, regardless of the shape of the non-image portion displayed on the display screen, by quickly identifying a portion that does not require lighting of the backlight light source and performing light emission control, It is possible to provide a backlight control device capable of more effectively realizing an energy saving effect by reducing power consumption, and a video display device including the device.

  In particular, according to the present invention, a mask pattern having a mask portion corresponding to the shape of the non-image portion of the display screen is held in advance, and the lighting / non-lighting of the backlight light source is controlled according to the mask pattern. It is possible to simplify and speed up the processing from detection of a non-image portion of the screen to switching of lighting of the backlight light source.

  Further, according to the present invention, a plurality of mask patterns are held in accordance with the shape of a non-image portion that can be taken when a video signal is displayed, and the image data of the mask pattern and the image data of the display screen are calculated. As a result, the mask pattern used for controlling the backlight source can be easily extracted, so that the backlight source can be controlled flexibly and easily according to various non-image area shapes. Become.

  According to the present invention, when a video signal is displayed on the screen, a mask pattern having a mask portion that matches the non-image portion of the display screen is extracted using a mask pattern prepared in advance, and the back corresponding to the mask pattern is extracted. Power consumption is reduced by controlling the lighting / non-lighting area of the light source. The mask pattern is prepared in advance assuming a pattern of a non-image portion that can be taken by the video signal.

  In this case, for example, the conventional no-image portion detection is performed by calculating a mask pattern prepared in advance and the no-image portion of the display screen obtained from the image signal, using a channel selection operation of the image display device as a trigger. It is possible to detect a non-image area appropriately (reasonably faster) than the method, determine a mask pattern corresponding to the non-image area, and turn off the light source of the backlight that does not need to be lit. The configuration and processing in the embodiment for carrying out the present invention will be specifically described below.

FIG. 1 is a block diagram for explaining a configuration example of a video display device provided with the backlight control device of the present invention, and shows an example of a television applicable as the video display device.
The television 10 includes a tuner 11 that selects a channel from a broadcast signal received by an antenna 23, and an external input unit 12 that inputs a video / audio signal from an AV device or a network externally connected to the television 10. ing. The video signal input from the tuner 11 or the external input unit 12 is processed by the video processing unit 13 according to the video format and video processing setting.

  Here, for example, YC separation processing, RGB decoding processing, A / D conversion processing, color space conversion processing, IP conversion processing, scaling processing, FRC processing, γ correction processing, color correction processing, synchronization detection processing, and the like are appropriately performed. . The video signal output from the video processing unit 13 includes a non-image part having a predetermined shape according to the type of the video source, the specification of the liquid crystal display panel 17, the video display mode of the liquid crystal display panel 17, and the like. May be included.

  The display device driver 15 controls the liquid crystal display panel 17 included in the display unit 16 in accordance with the video signal processed by the video processing unit 13. The video signal processed by the video processing unit 13 is also input to a pattern extraction / BL (backlight) control unit 19. The pattern extraction / BL control unit 19 performs lighting control of the backlight light source 18 included in the display unit 16. Illumination light from the backlight source 18 illuminates the liquid crystal display panel 17 from the back, and is modulated by the liquid crystal display panel 17 controlled according to the video signal to display an image.

  Further, at this time, the pattern extraction / BL control unit 19 calculates the image data of the display screen based on the video signal and the image data of the mask pattern stored in the memory 20 to match the shape of the non-image portion of the display screen. A mask pattern having a portion is extracted from the memory 20. Then, according to the extracted mask pattern, the lighting / non-lighting area of the backlight light source 18 is controlled according to a preset lighting control pattern. In this case, the region of the backlight light source 18 corresponding to the non-image portion of the display screen is not lit, and the region of the backlight light source 18 corresponding to the video portion that performs video display is lit.

  On the other hand, the audio signal output from the tuner 11 or the external input unit 12 is processed by the audio processing unit 21 and output from the speaker 22. The MCU 14 is a control unit that controls each unit of the television 10.

  A backlight control apparatus according to the present invention includes a storage unit that stores in advance a plurality of mask patterns that define a non-lighting area of a backlight light source as a mask portion, and a shape and mask pattern of a non-image portion of a display screen of a video signal to be displayed. A backlight that controls the lighting pattern of the backlight light source based on the determining means for determining whether or not the mask portions match, and the mask pattern determined by the determining means to match the shape of the non-image portion of the display screen And a light control means. In the example of FIG. 1, the storage unit is realized by the memory 20, and the determination unit and the backlight control unit are realized by the pattern extraction / BL control unit 19. The function of the pattern extraction / BL control unit 19 is executed by a computer using programs and data stored in advance in the memory 20 or the like.

  2A and 2B are diagrams illustrating a configuration example of a display unit including a backlight light source applicable to the present invention. FIG. 2A is a cross-sectional view of the display unit, and FIG. 2B is a liquid crystal display panel, a diffusion plate, or the like. It is a top view of the display unit in the state where the member is removed. This example shows a display unit using a plurality of LEDs as a backlight light source.

  In the display unit 16, a reflector (not shown) is installed on the bottom side of the housing 30, and a backlight light source using LEDs is disposed above the reflector. The backlight light source of this example includes a red LED 31 that emits red (R), a green LED 32 that emits green (G), and a blue LED 33 that emits blue (B). A white light source is obtained by mixing the light emission of these RGB three-color LEDs.

  Light emitted from each of the LEDs 31, 32, 33 is diffused by a diffusion plate 34 disposed further upward, and further receives an optical action by the optical sheets 35 to illuminate the liquid crystal display panel 17. The optical sheets 35 are members that give illumination light with light distribution characteristics and luminance distribution characteristics, for example, and diffusion sheets, prism sheets, reflective polarizing plates, and the like are used as appropriate.

  As a backlight light source, in addition to the above-described method using RGB three-color LEDs, a method of obtaining white by combining phosphors with short wavelength LEDs, a method of obtaining white by combining phosphors with blue LEDs, or blue A method of obtaining a white color by combining a yellow phosphor with an LED can be employed.

  As a means for dimming control of the LED light source, a voltage (current) dimming method, a duty dimming method in which brightness is time-division, or the like can be applied. In order to perform dimming control of the LED, various electric circuit components (all not shown) including an LED lighting circuit, a dimming control unit, an LED lighting circuit, and the like are collectively arranged on the back side of the LED substrate. .

For example, when a lighting device using a voltage (current) dimming method is applied, the dimming control unit changes the input voltage or input current from the power supply circuit with a DC-DC converter or the like, and the drive voltage (or current) is changed. Dimming is performed by changing the current of the LED connected directly as a load of the LED lighting circuit in size.
On the other hand, when the duty dimming method is applied, the dimming control unit generates a dimming pulse (PWM signal) for driving the LED lighting circuit, and the pulse width so as to obtain a duty ratio according to the PWM ratio setting data. The brightness of the LED can be dimmed by varying.

  In the embodiment according to the present invention, the lighting / non-lighting area of the backlight light source is controlled corresponding to the non-image portion of the display screen, and the non-image portion is not illuminated by the backlight light source. . In the backlight light source using the LED as in the present example, the lighting / non-lighting area can be controlled relatively easily with respect to various shapes of the non-image area. This is because a lighting region and a non-lighting region can be flexibly changed by a large number of LEDs arranged in a matrix or array.

  3A and 3B are diagrams showing another configuration example of a display unit including a backlight light source applicable to the present invention. FIG. 3A is a cross-sectional view of the display unit, and FIG. It is a top view of the display unit in a state where members such as a diffusion plate are removed. This example shows a display unit using a plurality of straight tube fluorescent tubes as a backlight light source.

In the display unit 16, a reflector (not shown) is installed on the bottom side of the housing 30, and a plurality of thin fluorescent tubes 41 are arranged at equal intervals above the reflector 30 to constitute a backlight light source.
The light emitted from the fluorescent tube 41 is diffused by the diffusion plate 42 disposed further upward, and further receives an optical action by the optical sheets 43 to illuminate the liquid crystal display panel 17. The optical sheets 43 are members that give illumination light with light distribution characteristics and luminance distribution characteristics, for example, and diffusion sheets, prism sheets, reflective polarizing plates, and the like are used as appropriate.

In order to control the lighting of the fluorescent tube 41, for example, in the display unit 16, the signal period ratio (duty) of the high potential level and the low potential level of the rectangular wave changes according to the backlight luminance adjustment signal input from the backlight control unit. A dimming control circuit that outputs a pulse width modulation output as a dimming signal, and generates an alternating voltage with a period and voltage according to the dimming signal from the dimming control circuit, And an inverter (all not shown) that is applied to the tube 41 and driven to light.
The inverter operates when the output of the dimming control circuit is at a high potential level, stops operating when the output is at a low potential level, and performs an intermittent operation according to the output duty of the dimming control circuit, thereby returning the backlight light source. Adjust the brightness.

In this example, the straight fluorescent tube 41 is arranged so that the tube axis direction thereof coincides with the horizontal direction of the screen. However, the fluorescent tube 41 is arranged in a non-image portion for controlling lighting / non-lighting. The direction, the arrangement position, the length in the tube axis direction, and the like are appropriately set in advance so as to correspond to the shape pattern.
In this case, it can be said that the fluorescent tube type backlight light source is somewhat inferior in terms of the degree of freedom in controlling the lighting / non-lighting area as compared with the above-described LED configuration. Fluorescent tubes 41 are arranged corresponding to the above, and the lighting area and non-lighting area can be controlled according to these non-image areas, thereby enabling lighting / non-lighting control for a frequently used pattern. To be able to function. Alternatively, in order to control the lighting of each area of each screen individually in correspondence with the case where one of the two screens becomes non-imaged, the half-length fluorescent tube is divided into two screens. You may make it provide corresponding to.

  In addition, as a display unit applied to this invention, you may apply what is called a hybrid type which used together said LED and fluorescent tube as a backlight light source.

  FIG. 4 is a diagram for explaining an example of shape detection processing of a non-image area in the present invention. FIG. 4A is a diagram showing an example of a mask pattern held in advance in the video display device, and FIG. ) Is a diagram showing an example of a display screen of a video signal to be displayed, and FIG. 4C is a diagram showing calculation results obtained by these calculations.

As described above, in the embodiment according to the present invention, a mask pattern having a mask portion corresponding to a non-image portion that can be taken by a display screen based on a video signal is stored in advance in a memory.
Then, when actually displaying an image, a mask having a mask portion having a shape that matches the non-image portion of the display screen by calculating image data of the display screen and image data of the mask pattern from the image signal to be displayed Extract a pattern from memory. Then, by controlling the lighting / non-lighting area of the backlight according to the extracted mask pattern, unnecessary illumination on the non-image area is prevented.

For example, it is assumed that the display screen of the video signal to be displayed is a display screen 110 as shown in FIG. The display screen 110 is formed by a video part 111 on which video is displayed and a non-picture part 112 without video. In this example, the screen is a side-edge type screen having an obi-shaped no-image portion 112 at both left and right ends of the screen.
Further, it is assumed that a mask portion 102 and a non-mask portion 101 are set in the mask pattern 100 of FIG. The mask unit 102 is set as an area where the backlight light source is not turned on.

  Then, the display screen 110 and the mask pattern 100 are compared. Specifically, the image data of each pixel on the display screen 110 and the image data of each pixel set in the mask pattern 100 are compared with each other at the same position, and the shape of the non-image portion 112 of the display screen 110 is determined. Is determined to match the mask portion 102 of the mask pattern 100. In this case, since the video signal to be displayed is a video signal after all video signal processing including scaling is completed, the video data is video data that matches the resolution (number of pixels) of the liquid crystal display panel.

  For example, when the video signal is generated by digital video data having a gradation of 8 bits, each pixel constituting the display screen is represented by 0 to 255 image data. In this example, the OR operation is performed on the image data of each pixel of the display screen and the image data of each pixel of the mask pattern held in the memory, so that the non-image portion of the display screen and the mask portion of the mask pattern are obtained. To match.

If the image data is ORed,
0 or 0 = 0
0 or 1 = 1
1 or 0 = 1
1 or 1 = 1
become.

For example, when the image data “100” and the image data “200” are ORed,
100 = 01100 100b
200 = 11001000b
100 or 200 = 11101 100b = 236
It becomes.

When comparing the image data of each pixel of the display screen 110 as shown in FIG. 4B with the image data of each pixel of the mask pattern 100 as shown in FIG. The image data of the pixel of the mask unit 102 is set to “0”, and the image data of the pixel of the non-mask unit 101 is set to “255”.
If one of the image data of each pixel of the display screen 110 is “200”, for example, if this pixel corresponds to the pixel of the mask portion 102 of the mask pattern,
0 = 00000000b
200 = 11001000b
0 or 200 = 110010100b = 200
Thus, the calculation result is always the same as the image data on the display screen 110.

On the other hand, since the image data of the non-mask portion 101 of the mask pattern 100 is “255”, when calculation is performed with the image data “200” of the pixel of the display screen 110,
255 = 11111111b
200 = 11001000b
255 or 200 = 11111111b = 255
Thus, the calculation result is always the same as the image data of the non-mask portion 101.

As described above, the pixel image data of the display screen 110 is compared with the pixel image data of the mask pattern 100 stored in the memory. At this time, image data of pixels at the same positions on the display screen 110 and the mask pattern 100 are calculated.
For example, when the image data of each pixel of the mask pattern 100 in FIG. 4A and the image data of each pixel on the display screen 110 in FIG. 4B are compared by OR operation, FIG. The calculation result 120 is as shown in FIG.

  Here, the image data of the mask portion 102 in the mask pattern 100 is compared with the image data of each pixel of the non-image portion 112 of the display screen 110. In this case, the image data of each pixel of the mask portion 102 of the mask pattern 100 is “0”, and the image data of each pixel of the non-image portion 112 of the display screen 110 is also “0”. All OR operations of these image data are “0”. Therefore, as shown in the calculation result 120 of FIG. 4C, a non-image portion 122 having a shape matching the mask portion 102 of the mask pattern 100 is obtained. The non-image portion 122 is an area where all the calculation results are “0”.

On the other hand, the image data of each pixel of the non-mask portion 101 in the mask pattern 100 of FIG. 4A is calculated as the image data of each pixel of the video portion 111 of the display screen 110 of FIG.
In this case, the image data of the non-mask portion 101 of the mask pattern 100 is “255”, and the image data of the video portion 111 of the display screen 110 can take a different value for each pixel. The OR operation between these image data is all “255”. Therefore, as shown in the calculation result 120 of FIG. 4C, a non-mask portion corresponding portion 121 having a shape that matches the non-mask portion 101 of the mask pattern 100 is obtained. The non-mask part corresponding unit 121 of the calculation result 120 is an area where the calculation results are all “255”, and in this case, corresponds to the video unit 111 of the display screen 110.

  By comparing the image data in this way, it can be determined whether or not the shape of the non-image portion 112 of the display screen 110 matches the mask portion 102 of the mask pattern 100 stored in the memory. For example, when the mask pattern 100 having a shape different from that shown in FIG. 4A is compared with the screen 110 shown in FIG. 4B, a pixel whose calculation result of the non-image portion 112 of the display screen 110 does not become “0”. Since a pixel that appears or a calculation result of the video part 111 does not become “255” appears, it can be determined that the non-image part 112 of the display screen 110 and the mask part 102 of the mask pattern 100 do not match. . In this case, the next mask pattern stored in the memory is used to perform calculation with the image data of each pixel on the display screen 110.

FIG. 5 is a diagram for explaining an example when calculation is performed using a mask pattern having a non-image portion shape different from the display screen of the video signal. FIG. 5A is held in advance by the video display device. FIG. 5B is a diagram showing an example of a display screen of a video signal to be displayed, and FIG. 5C is a diagram showing calculation results obtained by these calculations.
Here, image data of each pixel of the mask pattern 100 having the side edge type mask portion 102 as shown in FIG. 5A and a letterbox type non-image portion 112 as shown in FIG. Assume that the image data of each pixel of the display screen 110 is calculated by OR operation.

  In this case, a comparison between the image data of each pixel of the mask portion 102 in FIG. 5A and the image data of each pixel of the display screen 110 at a position corresponding to the mask portion 102 is shown in FIG. 5C. As described above, the non-image portion 122 whose calculation result is “0” is generated only at the four corners of the screen of the calculation result 120. In addition, a video unit 123 having the same image data as the image data of the image 110 in FIG. 5B is generated between the non-image units 122 at the left and right ends of the screen of the calculation result 120. Further, in the center, a non-masked part corresponding unit 121 whose operation results are all “255” is generated. In this case, the area of the non-mask part corresponding part 121 includes one part each of the non-picture part 112 and the video part 111 of the display screen.

  Through the processing so far, it can be seen that the mask portion 102 of the mask pattern 100 in FIG. 5A does not match the non-image portion 112 of the display screen 110, and this mask pattern 100 cannot be used for lighting control of the backlight light source. Can be judged.

Next, another example of mask pattern extraction processing will be described.
In the above example, the image data of all the pixels of the mask pattern 100 and the image data of all the pixels of the display screen 110 are calculated, but only the mask portion 102 of the mask pattern 100 has the pixels of the display screen 110. The calculation may be performed with the image data.

  For example, in the example of FIG. 4, only the image data of each pixel of the mask portion 102 of the mask pattern 100 is calculated with the image data of each corresponding pixel of the display screen 110, and the non-image portion 122 having the same shape in the calculation result 120 is obtained. If it can be detected, it is determined that they match. By the processing of this example, it is not necessary to compare the image data of all the pixels, so that a simple configuration and quick calculation processing can be performed.

  However, in this case, for example, even in the case of the display screen 110 in which the non-image portion 112 exists around as shown in FIG. 6, it may be determined that it matches the mask pattern in FIG. In this case, illumination light from the backlight light source is also emitted to the non-image parts at the top and bottom of the screen. Therefore, when a mask pattern is extracted by the processing of this example, a mask pattern 100 having a non-image area as shown in FIG. 6 is used first to calculate the image data of each pixel on the display screen 110. To do.

  That is, if there is a mask pattern that includes all mask portions of other mask patterns, such as a mask pattern having a mask portion corresponding to the non-image portion 112 in FIG. A mask pattern including other mask patterns is calculated to check whether it matches the shape of the non-image portion 112 of the display screen 110, and if it does not match, calculation with another mask pattern is performed. That's fine. This makes it possible to reliably extract a mask pattern having a mask portion that matches the non-image portion of the display screen.

In each of the above processing examples, the image data of each pixel of the mask pattern 100 stored in the memory and the image data of each pixel of the display screen 110 are compared by an OR operation, so that the non-image portion of the display screen 110 is displayed. Although the mask pattern 100 having the mask portion 102 that matches 112 is extracted, as another processing example, for example,
(1) The image data of each pixel of the mask pattern and the image data of each pixel of the display screen are all simply compared as they are to determine whether or not the respective image data match each other.
(2) Subtraction is performed between the image data of each pixel of the mask pattern and the image data of each pixel of the display screen, and it is determined that the image data whose result is “0” match each other.
(3) An XOR operation is performed between the image data of each pixel of the mask pattern and the image data of each pixel of the display screen, and it is determined that the image data whose result is “0” match each other.
Such a method can be applied. Note that the comparison or calculation of the above image data means that the image data of pixels located at the same place in the mask pattern 100 and the display screen 110 is compared or calculated in the same manner as the OR calculation.

An example of XRO calculation will be described below.
When image data is XORed,
0 xor 0 = 0
0 xor 1 = 1
1 xor 0 = 1
1 xor 1 = 0
become.

For example, when the image data “100” and the image data “200” are ORed,
100 = 01100 100b
200 = 11001000b
100 xor 200 = 10101 100b = 172
It becomes.

Also, for example, when the same image data 100 is ORed,
100 = 01100 100b
100 xor 100 = 00000000b = 0
It becomes.

  That is, when the image data of each pixel of the mask pattern and the image data of each pixel of the display screen are calculated using the XOR operation, the image data of the mask pattern is obtained for the pixel whose calculation result is “0”. It can be seen that the image data on the display screen matches. Here, similarly to the OR operation of FIG. 4 described above, in the mask pattern 100, the image data of each pixel of the mask portion 102 is set to “0”, and the image data of each pixel of the non-mask portion 101 is set to “255”. When the region where the calculation result 120 is “0” matches the mask portion 102 of the mask pattern 100, the mask portion 102 of the mask pattern 100 matches the non-image portion 112 of the display screen 110. Judgment can be made.

7 to 13 list examples of mask pattern and backlight light source lighting / non-lighting control. In each figure, a mask pattern prepared in advance is shown in FIG. (A), and a lighting control example of the backlight light source at this time is shown in FIG. (B). In the figure, reference numeral 130 denotes an entire lighting region of the backlight light source, 131 denotes a lighting region, and 132 denotes a light-off (non-lighting) region.
As shown in FIGS. 7 to 13, when the backlight light source is controlled to be turned on based on the mask pattern 100 having the mask portion 102 that matches the non-image portion of the display screen, it corresponds to the mask portion 102 of the mask pattern 100. The backlight light source in the area 132 is turned off (not lit), and the backlight light source in the area 131 corresponding to the non-mask part 101 is turned on. As a result, useless illumination light is not irradiated onto the non-image area of the display screen, and an energy saving effect can be realized by reducing the power consumption of the backlight light source.

FIG. 14 is a flowchart for explaining a control process example of a backlight light source by the backlight control apparatus according to the present invention.
The control unit of the video display device (e.g., corresponding to the pattern extraction / BL control unit 19 of the television 10) first acquires image data of the display screen from the video signal to be displayed on the liquid crystal display panel (step S1). As the image data, the image data of each pixel on the display screen of the video signal to be displayed as described above can be used.

  The control unit of the video display device then displays the nth (n = 1, 2, 3...) Mask pattern among the plurality of mask patterns stored in the memory and the image data of the display screen acquired in step S1. Are calculated (step S2). As a result of the calculation, it is determined whether or not the mask portion of the nth mask pattern matches the non-image portion of the display screen (step S3).

Here, as in the above example, the image data of each pixel of the display screen and the image data of each pixel of the mask pattern are calculated, and the mask portion of the nth mask pattern and the non-image of the display screen are calculated according to these results. It is determined whether the part matches. As the calculation method, a method such as the OR operation as described above can be appropriately employed. As a result of these calculations, if the mask portion of the mask pattern matches the non-image portion of the display screen, the nth mask pattern is extracted.
In addition, when calculating the image data of each pixel of the mask pattern and the image data of each pixel of the display screen, the above calculation may be performed only for the non-image portion of the mask pattern. You may make it operate | move about the data of an area | region.

  If the mask portion matches the non-image portion of the display screen in the n-th mask pattern, the lighting control of the backlight light source is performed with the n-th mask pattern (step S4). That is, as described above, the backlight light source corresponding to the mask portion in the mask pattern is turned off, and the backlight light source corresponding to the non-mask portion is turned on.

If the mask portion of the nth mask pattern does not match the non-image portion of the display screen in step S3, it is determined whether there is another mask pattern stored in the memory (step S5). If there is no other mask pattern in the memory, control to turn on the backlight light source is performed (step S6).
If there is another mask pattern in the memory, it is updated as n = n + 1 (step S7), and the process returns to step S2 to calculate the nth mask pattern and the image data on the display screen.

It is a block diagram for demonstrating the structural example of the video display apparatus provided with the backlight control apparatus of this invention. It is a figure which shows the structural example of the display unit provided with the backlight light source applicable to this invention. It is a figure which shows the other structural example of the display unit provided with the backlight light source applicable to this invention. It is a figure for demonstrating the example of a shape detection process of the no-image part in this invention. It is a figure for demonstrating the example when it calculates using the mask pattern which has a non-image part shape different from the display screen of a video signal. It is a figure which shows the example of the display screen in which a non-image part exists in the circumference | surroundings. It is a figure which shows the example of lighting / non-lighting control of a mask pattern and a backlight light source. It is a figure which shows the other example of lighting / non-lighting control of a mask pattern and a backlight light source. It is a figure which shows the further another example of lighting / non-lighting control of a mask pattern and a backlight light source. It is a figure which shows the further another example of lighting / non-lighting control of a mask pattern and a backlight light source. It is a figure which shows the further another example of lighting / non-lighting control of a mask pattern and a backlight light source. It is a figure which shows the further another example of lighting / non-lighting control of a mask pattern and a backlight light source. It is a figure which shows the further another example of lighting / non-lighting control of a mask pattern and a backlight light source. It is a flowchart for demonstrating the control processing example of the backlight light source by the backlight control apparatus by this invention. It is a figure which shows typically the example of a display of the video signal of a letterbox system. It is a figure which shows typically the example of a display of the video signal of a side panel system. It is a figure which shows the example which displays the video signal of aspect ratio 4: 3 on the display panel whose aspect ratio is 16: 9. It is a figure which shows the example which resizes and displays the part remove | excluding the non-image part from the letter box type or cinema type 4: 3 video signal to the aspect of 16: 9.

Explanation of symbols

3 ... RGB, 4 ... aspect ratio, 8 ... gradation, 10 ... TV, 11 ... tuner, 12 ... external input unit, 13 ... video processing unit, 14 ... MCU, 15 ... display device driver, 16 ... display unit, 17 DESCRIPTION OF SYMBOLS ... Liquid crystal display panel, 18 ... Back light source, 19 ... Pattern extraction / BL control part, 20 ... Memory, 21 ... Audio processing part, 22 ... Speaker, 23 ... Antenna, 30 ... Housing, 31 ... Red LED, 32 ... Green LED 33 ... Blue LED 34 ... Diffusion plate 35 ... Optical sheet 41 ... Fluorescent tube 42 ... Diffusion plate 43 ... Optical sheet 100 ... Mask pattern 101 ... Non-mask part 102 ... Mask part 110 ... Display screen 111 ... Video part 112 ... No picture part 120 ... Calculation result 121 ... Non-mask part corresponding part 122 ... No picture part 123 ... Video part 130 ... B Full lighting area of a scaling light source, 131 ... lighting area, 132 ... off (non-lighting) region.

Claims (12)

  1. A backlight control device that controls a backlight light source for illuminating a liquid crystal display panel that displays an image based on an input video signal,
    Storage means for storing in advance a plurality of mask patterns that define the non-lighting area of the backlight light source as a mask portion;
    Determining means for determining whether the shape of the non-image portion of the display screen of the video signal to be displayed matches the mask portion of the mask pattern;
    Backlight control means for controlling a lighting pattern of the backlight light source based on a mask pattern determined by the determining means to match the shape of the non-image portion of the display screen. Light control device.
  2. The backlight control device according to claim 1,
    The backlight control device, wherein the backlight control means performs control to turn off a backlight light source at a position corresponding to a mask portion of the mask pattern.
  3. In the backlight control device according to claim 1 or 2,
    The backlight control apparatus according to claim 1, wherein the mask pattern is a plurality of mask patterns having a mask portion that matches a shape of a non-image portion that can be taken when displaying an image based on a video signal.
  4. In the backlight control device according to claim 3,
    The determination means determines, for each of the plurality of mask patterns stored in the storage means, whether or not the mask portion of the mask pattern matches the shape of the non-image portion of the display screen,
    If there is a mask pattern having a mask portion that matches the shape of the non-image portion of the display screen, the backlight control means controls the lighting pattern of the backlight light source based on the mask pattern, and the non-image portion If there is no mask pattern having a mask portion that matches the shape of the backlight control device, the backlight control device controls to turn on all the backlight light sources.
  5. The backlight control device according to any one of claims 1 to 4,
    The determination means sets image data of each pixel at a position corresponding to the pixel on the display screen in the mask pattern, and sets the image data of the pixel on the display screen and the position corresponding to the pixel of the image data. A backlight control device that calculates image data of pixels of a mask pattern and determines whether or not the mask portion of the mask pattern matches the shape of the non-image portion of the display screen according to the calculation result .
  6. In the backlight control device according to claim 5,
    The determination means calculates the image data of all the pixels of the mask pattern with the image data of the pixels of the display screen.
  7. In the backlight control device according to claim 5,
    The backlight control apparatus according to claim 1, wherein the determination unit calculates only pixel image data of a mask portion of the mask pattern and pixel image data of the display screen.
  8. In the backlight control device according to claim 5,
    The backlight control apparatus according to claim 1, wherein the calculation is an OR operation of pixel data of pixels of the mask pattern and pixel data of pixels of the display screen.
  9. In the backlight control device according to claim 5,
    The backlight control apparatus according to claim 1, wherein the calculation is a calculation for comparing pixel data of pixels of the mask pattern with pixel data of pixels of the display screen.
  10. In the backlight control device according to claim 5,
    The backlight control apparatus according to claim 1, wherein the calculation is a subtraction of pixel data of pixels of the mask pattern and pixel data of pixels of the display screen.
  11. In the backlight control device according to claim 5,
    The backlight control apparatus according to claim 1, wherein the calculation is an XOR calculation of pixel data of pixels of the mask pattern and pixel data of pixels of the display screen.
  12.   12. The backlight control device according to claim 1, a backlight light source controlled by the backlight control device, and a liquid crystal display panel illuminated by the backlight light source, and the video signal A video display apparatus for displaying the video on the liquid crystal display panel.
JP2006297865A 2006-11-01 2006-11-01 Backlight control device and video display device equipped with the backlight control device Pending JP2008116554A (en)

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