JP4177652B2 - Liquid crystal display - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a liquid crystal display device that displays an image by irradiating a liquid crystal display panel using a backlight light source having a plurality of light emitting regions.
[0002]
[Prior art]
In recent years, display devices have also been required to be lighter and thinner due to lighter and thinner personal computers and television receivers. In accordance with such demands, liquid crystal display devices (LCDs) instead of cathode ray tubes (CRTs) have been demanded. ) Flat panel displays have been developed.
[0003]
The LCD applies an electric field to a liquid crystal layer having an anisotropic dielectric constant injected between two substrates, and adjusts the amount of light transmitted through the substrate by adjusting the strength of the electric field. A display device that obtains an image signal. Such LCDs are representative of portable and simple flat panel displays. Among these, TFT LCDs using thin film transistors (TFTs) as switching elements are mainly used.
[0004]
In such a liquid crystal display device, since the liquid crystal display panel itself does not emit light, it is usually necessary to dispose a backlight light source on the back surface of the liquid crystal display panel and irradiate the liquid crystal display panel. In order to reduce the power consumption due to the lighting of the backlight light source, for example, in Japanese Patent Laid-Open Nos. Hei 2-258087 and Hei 6-178240, when a synchronizing signal of an input video signal is not detected, or television reception is performed. It has been proposed to automatically turn off the backlight light source during the wave tuning operation.
[0005]
On the other hand, NTSC (National Television System Committee) color television broadcasts implemented in Japan have a video signal aspect ratio of 4: 3 and HDTV (High Definition). In the Television system, the aspect ratio of the video signal is standardized to a more horizontally long width, for example, 16: 9. Furthermore, in a movie or the like, a screen that is horizontally longer than an aspect ratio of 4: 3, which is referred to as a Vista size, is used.
[0006]
Therefore, the current letterbox is used so that the image content having a horizontally longer aspect ratio (for example, an aspect ratio of 16: 9) than the aspect ratio of 4: 3 can be received by a current NTSC television receiver (an aspect ratio of 4: 3). A display form called a method is used. In this letterbox system, as shown in FIG. 6 (a), a horizontally long screen (aspect ratio 16: 9), which is a video portion, is displayed at the center of a 4: 3 aspect ratio screen, and the upper and lower portions of the screen are displayed as images. This is a display form with no image, so that even in the current NTSC television receiver (aspect ratio 4: 3), it is possible to view movie software etc. without trimming left and right without trimming. (For example, JP-A-8-9284, JP-A-10-93985).
[0007]
Note that when this letterbox video signal is received by a wide television receiver with a horizontally long screen (aspect ratio of 16: 9), the upper and lower no-picture portions are not displayed on the screen, and only the video portion is displayed on the entire screen. Thus, a horizontally long screen (aspect ratio 16: 9) can be used effectively.
[0008]
In addition, in order to be able to receive image content having an aspect ratio of 4: 3 even with an HDTV television receiver (wide television receiver) having a horizontally long display screen (for example, an aspect ratio of 16: 9), FIG. As shown in FIG. 6 (b), a main screen having an aspect ratio of 4: 3, which is a video portion, is displayed at the center portion of the screen having an aspect ratio of 16: 9, and left and right portions thereof are displayed as non-image portions (side panel portions). ), A display form called a side panel system is known (for example, Japanese Patent Laid-Open Nos. 11-275487 and 2002-77768).
[0009]
[Patent Document 1]
Japanese Patent Laid-Open No. 2-280588 [Patent Document 2]
JP-A-6-178240 [0010]
[Problems to be solved by the invention]
In a conventional liquid crystal display device, for example, when the letterbox type or side panel type input video signal is displayed on the liquid crystal display panel as it is, depending on the aspect ratio of the video portion and the aspect ratio of the display screen, It is necessary to display a non-image area on the left and right sides (black display), but the backlight light source is always lit even in this non-image area display area, and there is a problem that wasteful power is consumed. It was.
[0011]
The present invention has been made in view of the above problems, and when displaying an image having an aspect ratio different from the aspect ratio of the screen of the liquid crystal display panel, the backlight light source is turned on for the non-image area display area. The present invention provides a liquid crystal display device capable of reducing wasteful power consumption by automatically stopping.
[0012]
[Means for Solving the Problems]
1st invention of this application is a liquid crystal display device which displays an image by irradiating a liquid crystal display panel using the backlight light source which has a some light emission area | region, Comprising: The non-image part contained in an input video signal A non-image portion detecting means for detecting the image, a first display mode for displaying the input video signal as it is, and a second display for displaying the screen by enlarging the vertical size or horizontal size of the video portion included in the input video signal. When the display mode switching means for switching the mode according to a user instruction and the first display mode are selected, the upper and lower or left and right portions of the display screen are displayed based on the detection result of the no-image portion detecting means. a light emitting region by turning off control of the backlight source corresponding to the image portion display area, when the second display mode is selected, the detection result of the non-picture portion detecting means Regardless, characterized in that a control means for lighting control of all the light-emitting region of the backlight source.
[0013]
According to a second aspect of the present invention, there is provided a partition member for partitioning the light emitting regions of the backlight light source.
[0015]
As described above, the liquid crystal display device of the present invention automatically turns off the light emission area of the backlight light source corresponding to the non-image area display area that does not require display light on the liquid crystal display panel, thus reducing wasteful power consumption and saving energy. Can be realized.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a liquid crystal display device according to a first embodiment of the present invention will be described in detail with reference to FIGS. Here, FIG. 1 is a functional block diagram showing a schematic configuration of the liquid crystal display device of the present embodiment, FIG. 2 is a schematic cross-sectional view of the liquid crystal display device of the present embodiment, (a) front sectional view, (b) side sectional view. FIG. 3 is an explanatory diagram showing an operation principle at the time of impulse-type display in the liquid crystal display device of the present embodiment.
[0017]
As shown in FIG. 1, the liquid crystal display device of this embodiment includes an active matrix type liquid crystal display panel 1 having a liquid crystal layer and electrodes for applying scanning signals and data signals to the liquid crystal layer, and an input video signal. The electrode driving unit 2 for driving the data electrodes and the scanning electrodes of the liquid crystal display panel 1, a direct backlight light source 3 disposed on the back surface of the liquid crystal display panel 1, and the backlight light source 3. And a light source driving unit 4 for turning on / off.
[0018]
Also, a vertical expansion processing unit 5 that expands the vertical size of the video portion in the letterbox type input video signal by line interpolation or the like, and a non-image portion that detects the presence or absence of a non-image portion added to the upper and lower portions from the input video signal A detection unit 6, a remote control light receiving unit 7 that receives an instruction signal input by a user using a remote controller (remote controller) (not shown), a detection result of a non-image part by the non-image part detection unit 6, and a remote control light reception unit 7 A control CPU 8 that outputs a predetermined control signal to the vertical extension processing unit 5 and the light source driving unit 4 based on the received instruction signal is provided.
[0019]
In this embodiment, a normally black mode liquid crystal display panel 1 having a display screen with an aspect ratio of 4: 3 is used. Further, as the backlight light source 3, a direct type or side illumination type LED light source, an EL light source, or the like can be used in addition to the direct type fluorescent lamp. Here, as shown in FIG. 2, the backlight light source 3 is constituted by eight direct fluorescent lamps (CCFT) corresponding to the respective light emitting areas divided in the horizontal direction (parallel to the scanning line). is doing.
[0020]
In addition, the liquid crystal display device of the present embodiment has a reflector 9 that reflects the light emitted from the backlight light source 3 toward the liquid crystal display panel 1, and diffuses the light emitted from the backlight light source 3 and the light reflected by the reflector 9. Thus, a diffusion plate 10 for irradiating the liquid crystal display panel 1 is provided. Here, the reflecting plate 9 is provided with a partition member 9a for partitioning between the fluorescent lamp lamps, and by this partition member 9a, each light emitting region irradiates each display region of the liquid crystal display panel 1 independently. It is possible to do.
[0021]
In the example shown in FIG. 2, the isosceles triangular section is maintained along the longitudinal direction (parallel to the scanning line) of each fluorescent lamp lamp in the partition member 9a having a cross section of an isosceles triangle. Although it is stretched as it is, its shape and size are not limited to this. Moreover, the partition member 9a may be a member independent of the reflecting plate 9, or may be integrally formed of the same material.
[0022]
The operation of the liquid crystal display device configured as described above will be described. When a user displays a letterbox-type input video signal having an aspect ratio of 4: 3 on the liquid crystal display panel 1 using the remote controller, the non-image portion without video is displayed (black display) on the upper and lower portions of the display screen. The first display mode (see FIG. 6A), or the second display that displays an image on the entire screen by changing the vertical size of the video portion having an aspect ratio of 16: 9 included in the input video signal. One of the modes can be switched.
[0023]
When the first display mode is instructed, when a letterbox video signal is input, the upper and lower portions of the liquid crystal display panel 1 become the non-image area display area, where the non-image area is displayed (black display). ) Since no display light (backlight) is required in this non-image area display area, the light emission area of the backlight light source 3 corresponding to this non-image area display area based on the detection result of the no-image detection section 6. The control CPU 8 controls the light source driving unit 4 so as to turn off the light.
[0024]
Here, of the eight fluorescent lamps, two fluorescent lamps positioned at the upper and lower ends are light emitting areas corresponding to the non-image area display area. Turn off only the two fluorescent lamps. Here, for example, when inputting a CM image with an aspect ratio of 4: 3 inserted in the air of a 16: 9 movie, the control CPU 8 controls the light source drive unit 4 because no image portion is not detected. Thus, the two fluorescent lamps at the upper and lower ends are lit in the same manner as the other six fluorescent lamps.
[0025]
Further, when the second display mode is instructed, when a letterbox video signal is input, the control CPU 8 controls the vertical expansion processing unit 5 to control the vertical size of the video unit with an aspect ratio of 16: 9. In order to enlarge the image, the liquid crystal display panel 1 displays a video portion in which the vertical size is expanded over the entire screen having an aspect ratio of 4: 3. Therefore, the control CPU 8 controls the light source driving unit 4 so that all the eight fluorescent lamp lamps are turned on to irradiate the entire display screen of the liquid crystal display panel 1.
[0026]
As described above, the liquid crystal display device of the present embodiment detects the presence or absence of a non-image area in the input video signal, and irradiates only the video area display area based on the detection result, Since turning on / off each light emitting area of the backlight light source 3 is automatically controlled to stop the irradiation, it is possible to reduce useless power consumption and realize energy saving without any special operation by the user. It becomes.
[0027]
Further, in the present embodiment, since the partition member 9a for partitioning the light emitting areas of the backlight light source 3 is provided, it is possible to efficiently irradiate the image display area with the backlight light. is there. Further, since a plurality of light emitting regions are provided in the direction parallel to the scanning lines, by sequentially driving these light sources within one vertical period, a pseudo drive type display is changed to an impulse type drive display such as a CRT. It is also possible to prevent motion blur interference that occurs when displaying moving images. This scanning backlight driving method will be described with reference to FIG.
[0028]
After the scanning (image writing) of a certain horizontal line group (display divided area) is completed, the light emitting area (fluorescent lamp) corresponding to the horizontal line group is considered in consideration of the response delay of the liquid crystal. ) Is lit. This is repeated with the next region in the vertical direction. As a result, as shown by the broken line portion in FIG. 3, the backlight lighting period can be sequentially shifted in units of light emitting areas with the passage of time corresponding to the writing scanning position of the video signal.
[0029]
Here, in the second display mode, since the video portion is displayed on the entire screen, as shown in FIG. 3A, eight fluorescent lamps are used as the respective light emitting areas, and these are set in one frame (for example, 60 Hz). In the case of progressive scan, it is controlled so that the scan lights up sequentially within 16.7 msec). As a result, it is possible to prevent motion blur and reduce power consumption by shortening the lighting period of each fluorescent lamp.
[0030]
In the first display mode, the upper and lower parts of the screen are the non-image area display area. Therefore, as shown in FIG. 3B, two fluorescent lamps at the upper and lower ends corresponding to the non-image area display area are displayed. The light is turned off, and only the six fluorescent lamps corresponding to the video portion display area having an aspect ratio of 16: 9 are sequentially turned on. As a result, it is possible not only to prevent motion blur but also to further reduce power consumption by not lighting the fluorescent lamp corresponding to the non-image area display area.
[0031]
In the above-described embodiment, the description has been given of the case where the light emission area of the backlight light source corresponding to the non-image area display area when displaying the letterbox image having the aspect ratio of 4: 3 is automatically turned off. Not limited to this, when displaying image content with various aspect ratios different from the aspect ratio of the display screen, the light emission area of the backlight light source corresponding to the non-image area display area formed on the liquid crystal display panel is automatically turned off. It goes without saying that it should be done.
[0032]
In the case of displaying image content having such various aspect ratios, by adopting a direct type LED light source as a backlight light source, it becomes possible to subdivide and set the light emission divided region. Reduction of power consumption can be realized efficiently.
[0033]
Next, a liquid crystal display device according to a second embodiment of the present invention will be described in detail with reference to FIGS. 4 and 5. The same reference numerals are given to the same portions as those in the first embodiment, and description thereof will be omitted. Here, FIG. 4 is a functional block diagram showing a schematic configuration of the liquid crystal display device of the present embodiment, FIG. 5 is (a) a plan sectional view showing a schematic configuration of the liquid crystal display device of the present embodiment, and (b) a front sectional view. It is.
[0034]
As shown in FIG. 4, the liquid crystal display device of the present embodiment includes a normally black mode liquid crystal display panel 11 having a display screen with an aspect ratio of 16: 9, and a plurality of pixels divided in a direction perpendicular to the scanning lines. The backlight light source 13 having a light emitting region is provided. In addition, when a side panel video signal having an aspect ratio of 16: 9 is input, a horizontal expansion processing unit 15 is provided that expands the horizontal size of the video part having an aspect ratio of 4: 3 by pixel interpolation or the like in accordance with a user instruction. .
[0035]
In the present embodiment, as shown in FIG. 5, the backlight light source 13 is constituted by eight direct fluorescent lamps (CCFT) arranged so that the longitudinal direction extends in the vertical direction. As in the first embodiment, a plurality of direct-type or side-irradiation type LED light sources, EL light sources, and the like may be used. Further, the reflector 9 that reflects the light emitted from the backlight light source 13 toward the liquid crystal display panel 11 is provided with a partition member 9a for partitioning the fluorescent lamps, as in the first embodiment. It is the same.
[0036]
The operation of the liquid crystal display device configured as described above will be described. When the user displays a side panel type input video signal having an aspect ratio of 16: 9 on the liquid crystal display panel 11 by using the remote controller, a non-image portion without video is displayed (black display) on the left and right portions of the display screen. The first display mode (see FIG. 6B), or the second display for displaying an image on the entire screen by changing the horizontal size of the video part having an aspect ratio of 4: 3 included in the input video signal. One of the modes can be switched.
[0037]
When the first display mode is instructed, when a side panel video signal is input, the left and right parts of the screen of the liquid crystal display panel 1 become the non-image area display area, where the non-image area is displayed (black display). ) Since no display light (backlight) is required in this non-image area display area, the light emission area of the backlight light source 13 corresponding to this non-image area display area based on the detection result of the no-image detection section 6. The control CPU 8 controls the light source driving unit 4 so as to turn off the light.
[0038]
Here, of the eight fluorescent lamps, two fluorescent lamps located at the left and right ends are light emitting areas corresponding to the non-image area display area. Turn off only the two fluorescent lamps. For example, when inputting a CM image with an aspect ratio of 4: 3 inserted in a broadcast program of a movie with an aspect ratio of 16: 9, a non-image area is detected. Only the two fluorescent lamps are turned off.
[0039]
In addition, when the second display mode is instructed, when a side panel video signal is input, the control CPU 8 controls the horizontal expansion processing unit 15 to control the horizontal size of the video unit having an aspect ratio of 4: 3. Therefore, the liquid crystal display panel 11 displays the video portion with the horizontal size expanded on the entire screen with an aspect ratio of 16: 9. Accordingly, the control CPU 8 controls the light source driving unit 4 so as to turn on all eight fluorescent lamps so as to irradiate the entire display screen of the liquid crystal display panel 11.
[0040]
As described above, in the liquid crystal display device of the present embodiment, the presence or absence of a non-image portion in the input video signal is detected, and based on the detection result, only the video portion display region is irradiated, and the non-image portion display region Since the lighting / extinction in each light emitting area of the backlight light source 13 is automatically controlled so as to stop the irradiation of the light source, even if there is no special operation by the user, it is possible to reduce wasteful power consumption and realize energy saving. It becomes possible.
[0041]
In the above-described embodiment, the description has been given of the case where the light emission area of the backlight light source corresponding to the non-image area display area when the side panel image having the aspect ratio of 16: 9 is displayed is automatically turned off. Not limited to this, when displaying image content with various aspect ratios different from the aspect ratio of the display screen, the light emission area of the backlight light source corresponding to the non-image area display area formed on the liquid crystal display panel is automatically turned off. It goes without saying that it should be done.
[0042]
In the case of displaying image content having such various aspect ratios, by adopting a direct type LED light source as a backlight light source, it becomes possible to subdivide and set the light emission divided region. Reduction of power consumption can be realized efficiently.
[0043]
【The invention's effect】
Since the liquid crystal display device of the present invention is configured as described above, the light emission area of the backlight source corresponding to the non-image area display area when displaying an image having an aspect ratio different from the aspect ratio of the liquid crystal display panel is provided. Since it automatically turns off, it is possible to reduce energy consumption by reducing wasteful power consumption.
[Brief description of the drawings]
FIG. 1 is a functional block diagram showing a schematic configuration in a first embodiment of a liquid crystal display device of the present invention.
2A is a front sectional view showing a schematic configuration of the liquid crystal display device according to the first embodiment of the present invention, and FIG.
FIG. 3 is an explanatory diagram illustrating an operation principle during impulse-type display in the first embodiment of the liquid crystal display device of the present invention.
FIG. 4 is a functional block diagram showing a schematic configuration in a second embodiment of the liquid crystal display device of the present invention.
FIGS. 5A and 5B are a schematic cross-sectional view and a front cross-sectional view, respectively, showing a schematic configuration of a liquid crystal display device according to a second embodiment of the present invention.
6A is a letterbox image having an aspect ratio of 4: 3 including an image portion having an aspect ratio of 16: 9, and FIG. 6B is a side panel image having an aspect ratio of 16: 9 including an image portion having an aspect ratio of 4: 3. It is explanatory drawing shown, respectively.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1, 11 Liquid crystal display panel 2 Electrode drive part 3, 13 Backlight light source 4 Light source drive part 5 Vertical expansion process part 6 No image part detection part 7 Remote control light-receiving part 8 Control CPU
15 Horizontal stretch processing unit

Claims (2)

A liquid crystal display device that displays an image by irradiating a liquid crystal display panel using a backlight light source having a plurality of light emitting regions,
A non-image portion detecting means for detecting a non-image portion included in the input video signal;
A display that switches between a first display mode in which an input video signal is displayed on the screen as it is and a second display mode in which the vertical or horizontal size of the video portion included in the input video signal is enlarged and displayed on the screen according to a user instruction. Mode switching means;
When the first display mode is selected, based on the detection result of the no-image portion detection unit, the light emission region of the backlight light source corresponding to the no-image portion display regions of the upper and lower or left and right portions on the display screen by turning off control, when the second display mode is selected, regardless of the detection result of the non-picture portion detecting means, and control means for lighting control of all the light-emitting region of the backlight source A liquid crystal display device characterized by the above. The liquid crystal display device according to claim 1,
A liquid crystal display device comprising a partition member for partitioning light emitting regions of the backlight light source.

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