JP2010026248A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a direct-view type liquid crystal display device providing high contrast and achieving reduced consumption energy. <P>SOLUTION: The liquid crystal display device includes: a two-dimensional scan driving part which causes a light spot formed by a light beam from a light source to two-dimensionally scan on a rear surface of an image display region 11c of a liquid crystal panel in a main scanning direction Dh and a subscanning direction Dv; a two-dimensional scan control part which supplies a scan timing signal to the two-dimensional scan driving part; a divided region control part which divides the image display region 11c into a plurality of regions E1 to E12 and outputs illuminating light correction coefficients based on an input image signal per divided region; and an emission intensity control part which controls the emission intensity of the light beam on the basis of illuminating light correction coefficients per divided region. The emission intensity of the light beam is controlled by the emission intensity control part on the basis of illuminating light correction coefficients of one or more regions out of the plurality of regions and scan timings in the main scanning direction and the subscanning direction of a two-dimensional scanning part. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a liquid crystal display device that performs backlight illumination of a direct-view type liquid crystal panel by two-dimensional scanning of a light beam, and particularly relates to control of the intensity of backlight illumination.

  Generally, in a liquid crystal display device (LCD), the entire image display area of a liquid crystal panel is backlit. Since the liquid crystal panel cannot completely block the backlight illumination light, the dark image is not sufficiently dark and high contrast cannot be obtained. As an improvement measure, there has been proposed a display device that deflects light emitted from a light source and scans the entire surface of an image display area (image information display element) of a liquid crystal panel within one frame period (for example, a patent). Reference 1). This display device improves the dynamic range by controlling the luminance value by changing the scanning speed in accordance with the video signal.

Japanese Patent Laying-Open No. 2004-163915 (paragraphs 0048 to 0056, FIG. 4)

  However, the display device described in Patent Document 1 has a problem in that the contrast is not sufficiently improved because backlight illumination is performed even on a portion that is desired to be displayed darkly.

  Further, in the display device described in Patent Document 1, in order to change the scanning speed of the light spot, the driving speed of the two-dimensional scanning device constituted by two polygon mirrors or a polygon mirror and a single-vibration mirror body is set. Since it is controlled, there is a problem that the energy consumption increases when the scanning speed is increased.

  Further, the display device described in Patent Document 1 has a problem that energy consumption is wasted because backlight illumination is performed even on a portion that is desired to be displayed darkly.

  Accordingly, the present invention has been made to solve the above-described problems of the prior art, and an object of the present invention is to provide a liquid crystal display device capable of obtaining high contrast and reducing energy consumption. is there.

  A liquid crystal display device according to the present invention includes a liquid crystal panel, a liquid crystal drive signal generating unit that generates a liquid crystal drive signal based on an input video signal, a liquid crystal drive unit that drives the liquid crystal panel based on the liquid crystal drive signal, A light source that emits a light beam, and deflects the light beam to two-dimensionally scan a light spot formed by the light beam in the main scanning direction and the sub-scanning direction on the back surface of the image display area of the liquid crystal panel. Two-dimensional scanning control means for supplying a scanning timing signal in the main scanning direction and sub-scanning direction of the light spot to the two-dimensional scanning driving means; and a plurality of image display areas on the liquid crystal panel. Divided region control means for outputting an illumination light correction coefficient based on the input video signal for each of the regions, and for each region based on the illumination light correction coefficient Emission intensity control means for controlling the emission intensity of the light beam, and the emission intensity control means controls the emission intensity of the light beam by scanning the light beam in the plurality of regions. The illumination light correction coefficient is calculated based on the illumination light correction coefficient of the area or the illumination light correction coefficient of any one of the two or more areas scanned by the light beam in the plurality of areas, and the light emission The switching timing of the illumination light correction coefficient used for controlling the emission intensity of the light beam by the intensity control means is determined based on the scanning timing signal from the two-dimensional scanning control means.

  According to the liquid crystal display device of the present invention, it is possible to display an image with a high contrast and to achieve energy saving.

Embodiment 1 FIG.
FIG. 1 is a diagram schematically showing the configuration and operation of a liquid crystal display device according to Embodiment 1 of the present invention. FIG. 2 is a diagram schematically showing the configuration of the optical system and the control system of the liquid crystal display device according to the first embodiment.

  As shown in FIG. 1 or 2, the liquid crystal display device according to the first embodiment includes a liquid crystal panel 11 and a liquid crystal drive signal as a liquid crystal drive signal generation unit that generates a liquid crystal drive signal A1 based on an input video signal. The generating unit 12, the liquid crystal driving unit 13 as a liquid crystal driving unit for driving the liquid crystal panel 11 based on the liquid crystal driving signal A1, the light beam emitting unit 20 for emitting the light beam L0, and the image display area 11c of the liquid crystal panel 11 A two-dimensional scanning drive as a two-dimensional scanning means for two-dimensionally scanning a light beam L1 as backlight illumination light on the back surface 11b of the liquid crystal panel 11; And a two-dimensional scanning control unit 31 that outputs a control signal (scanning timing signal) A3 of the two-dimensional scanning driving unit 30. The divided area control unit 23 performs a process of dividing the image display area 11c of the liquid crystal panel 11 into a plurality of areas and a process of determining an illumination light correction coefficient for each of the divided areas. The illumination light correction coefficient is determined, for example, according to the luminance of the video displayed in each divided area. For example, if the luminance of the video displayed in each divided area is high, an illumination light correction coefficient (for example, a high value illumination light correction coefficient) that increases the intensity of the light beam L0 from the light source 21 is generated and divided. If the luminance of the image displayed in each region is low, an illumination light correction coefficient (for example, a low value illumination light correction coefficient) that reduces the intensity of the light beam L0 from the light source 21 is generated. In this case, as the luminance of the video displayed in the divided area, the maximum value, the minimum value, or the intermediate value of the luminance of each pixel in the area can be used, and each pixel in the area can be used. It is also possible to use an average value of luminances.

  As shown in FIG. 1 or FIG. 2, the liquid crystal panel 11 is a direct view type liquid crystal panel in which the surface 11a is directly viewed by an observer. A light beam L1 emitted from the light beam emitting unit 20 and scanned by the two-dimensional scan driving unit 30 is irradiated on the back surface 11b of the image display area (shaded portion in FIG. 2) 11c of the liquid crystal panel 11. The two-dimensional scanning drive unit 30 can be constituted by, for example, a polygon mirror, a galvanometer mirror, and a drive control unit that drives them. However, the two-dimensional scanning drive unit 30 is not limited to this configuration, and may be another configuration that realizes two-dimensional scanning, for example, a MEMS (Micro Electro Mechanical Systems).

  As shown in FIG. 2, the light beam emitting unit 20 includes a light source 21 that emits a light beam, and a light emission intensity control unit 22 that controls the light emission intensity of the light beam L0 emitted from the light source 21. . The emission intensity control unit 22 outputs a control signal to the light source 21 based on the illumination light correction coefficient A2 output from the divided region control unit 23 and the scanning timing signal A3 output from the two-dimensional scanning control unit 31. The light source 21 is, for example, an optical device having a laser light emitting element or an LED element, but may be an optical device having a light emitting lamp such as a high-intensity mercury lamp as a light source as long as the light beam can be emitted. It is.

  Further, as shown in FIG. 1 or FIG. 2, the two-dimensional scan driving unit 30 controlled by the two-dimensional scan control unit 31 deflects the light beam L0 from the light beam emitting unit 20 in the horizontal direction and the vertical direction. As a result, light spots formed by the light beam L1 are respectively transmitted to the main scanning direction (horizontal direction) Dh and the sub-scanning direction (vertical direction) Dv on the back surface 11b of the image display area 11c of the liquid crystal panel 11 (predetermined frequencies (predetermined) And the entire surface of the back surface 11b of the image display area 11c of the liquid crystal panel 11 is line-sequentially scanned with a light spot. It should be noted that the image information on the entire surface of the liquid crystal panel 11 is rewritten, and 1/60 seconds is defined as one frame period. During this period, the entire surface of the liquid crystal panel 11 is scanned with a light spot to perform backlight illumination.

  3A is a diagram for explaining regions E1 to E12 that divide the image display region 11c of the liquid crystal panel 11 in the liquid crystal display device according to the first embodiment, and FIG. It is a figure for demonstrating the relationship between the scanning positions P1-P7 of the area | regions E1-E12 divided | segmented by 3 (a), and the light spot (it shows seven with a broken-line circle).

  As shown in FIG. 3A, the light spot scans a plurality of scanning operations in the main scanning direction Dh from the scanning start position S1 in the main scanning direction Dh of the liquid crystal panel 11 as in the scanning position P1 of the first line. The scanning positions (for example, P1 to P7) are sequentially performed from the top, for example, and scanned to the lowest end (scanning position P7) on the back surface 11b of the image display area 11c of the liquid crystal panel 11. Here, at the timing when the light spot illuminates a certain area of the image display area 11c of the liquid crystal panel 11, the light emission intensity control unit 22 is output based on the illumination light correction coefficient A2 output from the divided area control unit 23. The light source 21 is controlled to determine the light emission intensity of the light beam L0. At the timing of simultaneously illuminating two or more of the plurality of regions E1 to E12 with the light spot (that is, straddling two or more regions), the light emission intensity control unit 22 performs the illumination light correction coefficient for each region. Are compared to select which region the light emission intensity of the light beam L0 is to be controlled based on the illumination light correction coefficient of which region.

  That is, the control of the light emission intensity of the light beam L0 by the light emission intensity control unit 22 is performed by adjusting the illumination light correction coefficient of one region scanned by the light beam L0 among the plurality of regions determined by the divided region control unit 23, Alternatively, the light emission is performed based on the illumination light correction coefficient of any one of the two or more areas scanned by the light beam L0 in the plurality of areas determined by the divided area control unit 23. The switching timing of the light emission intensity of the light beam L0 by the intensity controller 22 (that is, the switching timing of the illumination light correction coefficient to be used) is determined based on the scanning timing signal from the two-dimensional scanning controller 31. As described above, the light beam is emitted based on the scanning timing signal A3 in the main scanning direction Dh and the sub-scanning direction Dv of the two-dimensional scanning output from the two-dimensional scanning control unit 31, and the illumination light correction coefficient A2 for each region. By controlling the intensity, an image with high contrast can be obtained. Further, when displaying a dark image, energy saving can be realized because the output of the light source 21 is controlled to be low.

  Next, the case where the image display area 11c of the liquid crystal panel 11 is divided into 12 rectangular areas E1 to E12 of 4 columns and 3 rows as shown in FIG. 3A will be described. In addition, the size of the light spot is sufficiently larger than the pixel size of the liquid crystal panel 11 and smaller than the size of each region into which the liquid crystal panel 11 is divided. As shown in FIG. 3B, when the number of scans in the sub-scanning direction Dv is 7, the odd-line main scan (scanning positions P1, P3, P5, P7) illuminates the vicinity of the boundary with a light spot. In the main scanning of the even lines (scanning positions P2, P4, P6), the vicinity of the center of the area is illuminated with the light spot.

  FIG. 4 is a diagram for explaining input video signals in areas E1 to E12 that divide the image display area 11c of the liquid crystal panel in the liquid crystal display device according to the first embodiment. The region divided by the divided region control unit 23 ideally corresponds to the pixel on a one-to-one basis, but is driven by controlling the two-dimensional scan driving unit 30 and the light source 21 for each pixel. Since this involves technical difficulties, a range including a plurality of pixels is defined as one region. As shown in FIG. 4, in the luminance distribution of one frame with an input video signal, the region E7 has the highest luminance (the gradation level is high), and the luminances of the regions E6, E10, and E11 are halftones (steps). In other areas E1 to E5, E8, E9, and E12, the luminance is the lowest (the gradation level is low). In FIG. 4, since main scanning is performed at seven positions P1 to P7 in the sub-scanning direction Dv, one of the plurality of areas E1 to E12 dividing the liquid crystal panel 11 is illuminated (scanned). And when illuminating (scanning) across two or more of the plurality of regions E1 to E12. For this reason, it is necessary to determine which region of the illumination light correction coefficient is to be subjected to output control of the light source 21 at that timing.

FIG. 5 is a diagram showing the intensity I of the light beam from the light source 21 at the timing of illuminating the areas E1 to E12 with the light spot in the liquid crystal display device according to the first embodiment. In FIG. 5, 11c represents an image display area of the liquid crystal panel, E1 to E12 represent areas obtained by dividing the image display area, and P1 to P7 represent scanning positions in the main scanning direction Dh (positions in the sub-scanning direction Dv). , I _{11 to} I ₁₇ indicate changes in the light emission intensity of the light source 11 on the image display region 11c (that is, changes in the illumination light correction coefficient used) in a coordinate system in which the horizontal axis is Dh and the vertical axis is intensity I. ing. In the first embodiment, as shown in FIG. 5, the emission intensity control unit 22 controls the emission intensity of the light beam L0 from the light source 21 when the light spot scans two or more regions. This is performed based on the illumination light correction coefficient in the region having the lowest gradation level among the two or more regions.

First, the main scanning of the first line (scanning position P1) in FIG. 5 will be described. The illumination light that turns off the light beam L0 from the light source 21 has the lowest gradation level in the region E1, the region E2, the region E3, and the region E4 that are illuminated by the main scanning (scanning position P1) of the first line. A correction coefficient (illumination light correction coefficients for the areas E1, E2, E3, and E4) is selected. As a result, as shown in FIG. 5, the intensity I ₁₁ of the light beam L0 from the light source 21 in the first line of the main scanning (scanning position P1) maintains zero.

The main scanning of the second line (scanning position P2) in FIG. 5 will be described. The area E1, the area E2, the area E3, and the area E4, which are illuminated by the main scanning of the second line (scanning position P2), have the lowest gradation level, so that the light beam L0 from the light source 21 is turned off. A light correction coefficient (illumination light correction coefficient in the areas E1, E2, E3, and E4) is selected. As a result, as shown in FIG. 5, the intensity I ₁₂ of the light beam L0 from the light source 21 in the main scanning of the second line (scanning position P2) is maintained zero.

The main scanning of the third line (scanning position P3) in FIG. 5 will be described. The areas illuminated by the light spot in the main scanning of the third line (scanning position P3) are areas E1, E5, areas E2, E6, areas E3, E7, and areas E4, E8. Further, in the middle of the movement of the light spot from the regions E1 and E5 to the regions E2 and E6, there is a period in which illumination is performed across the regions E1, E5, E2, and E6. In the middle of the movement of the light spot from the areas E2 and E6 to the areas E3 and E7, there is a period in which illumination is performed across the areas E2, E6, E3 and E7. Further, in the middle of the movement of the light spot from the areas E3, E7 to the areas E4, E8, there is a period of illumination across the areas E3, E7, E4, E8. In the first embodiment, when the light spot moves across two or more regions, the intensity of the light beam is based on the illumination light correction coefficient of the region having the lowest gradation level among the two or more regions. Adjustments are made. As a result, as shown in FIG. 5, the intensity I ₁₃ of the light beam L0 from the light source 21 in the main scanning of the third line (scanning position P3) maintains zero.

The main scanning of the fourth line (scanning position P4) in FIG. 5 will be described. The areas illuminated by the light spot in the fourth line (scanning position P4) are the areas E5, E6, E7, and E8. Further, in the middle of the movement of the light spot from the region E5 to the region E6, there is a period in which illumination is performed across the regions E5 and E6. Further, in the middle of the movement of the light spot from the region E6 to the region E7, there is a period in which illumination is performed across the regions E6 and E7. Further, in the middle of the movement of the light spot from the region E7 to the region E8, there is a period in which illumination is performed across the regions E7 and E8. In the first embodiment, when the light spot moves across two or more regions, the intensity of the light beam is based on the illumination light correction coefficient of the region having the lowest gradation level among the two or more regions. Adjustments are made. As a result, the intensity I ₁₄ of the light beam L0 from the light source 21 in the main scanning of the fourth line (scan position P4), as shown in FIG. 5, the higher in the area E6 and region E7.

The main scanning of the fifth line (scanning position P4) in FIG. 5 will be described. The areas illuminated by the light spot in the fifth line (scanning position P4) are areas E5 and E9, areas E6 and E10, areas E7 and E11, and areas E8 and E12. Further, in the middle of the movement of the light spot from the areas E5 and E9 to the areas E6 and E10, there is a period of illumination across the areas E5, E9, E6 and E10. Further, in the middle of the movement of the light spot from the regions E6 and E10 to the regions E7 and E11, there is a period in which illumination is performed across the regions E6, E10, E7, and E11. Further, in the middle of the movement of the light spot from the areas E7, E11 to the areas E8, E12, there is a period of illumination across the areas E7, E11, E8, E12. In the first embodiment, when the light spot moves across two or more regions, the intensity of the light beam is based on the illumination light correction coefficient of the region having the lowest gradation level among the two or more regions. Adjustments are made. As a result, the intensity I ₁₅ of the light beam L0 from the light source 21 in the main scanning of the first five lines (scanning position P5), as shown in FIG. 5, the higher in the area E6 and region E7.

The main scanning of the sixth line (scanning position P6) in FIG. 5 will be described. The regions illuminated by the light spot in the main scanning of the sixth line (scanning position P6) are region E9, region E10, region E11, and region E12. In the middle of the movement of the light spot from the region E9 to the region E10, there is a period in which illumination is performed across the regions E9 and E10. Further, in the middle of the movement of the light spot from the region E10 to the region E11, there is a period in which illumination is performed across the regions E10 and E11. Further, in the middle of the movement of the light spot from the region E11 to the region E12, there is a period in which illumination is performed across the regions E11 and E12. In the first embodiment, when the light spot moves across two or more regions, the intensity of the light beam is based on the illumination light correction coefficient of the region having the lowest gradation level among the two or more regions. Adjustments are made. As a result, the intensity _{I 16} of the light beam L0 from the light source 21 in the main scanning of the first six lines (scanning position P6), as shown in FIG. 5, the higher in the region E10 and the region E11.

The main scanning of the seventh line (scanning position P7) in FIG. 5 will be described. The area illuminated by the light spot in the main scanning of the seventh line (scanning position P7) is the boundary in the horizontal direction of the area E9, the area E10, the area E11, and the area E12. In the middle of the movement of the light spot from the region E9 to the region E10, there is a period in which illumination is performed across the regions E9 and E10. Further, in the middle of the movement of the light spot from the region E10 to the region E11, there is a period in which illumination is performed across the regions E10 and E11. Further, in the middle of the movement of the light spot from the region E11 to the region E12, there is a period in which illumination is performed across the regions E11 and E12. In the first embodiment, when the light spot moves across two or more regions, the intensity of the light beam is based on the illumination light correction coefficient of the region having the lowest gradation level among the two or more regions. Adjustments are made. As a result, the intensity _{I 17} of the light beam L0 from the light source 21 in the main scanning of the 7th line (scan position P7), as shown in FIG. 5, the higher in the region E10 and the region E11.

  In the above description, the case of performing scanning in the main scanning direction Dh at the seven positions P1 to P7 in the sub-scanning direction Dv has been described. However, the number of positions in the sub-scanning direction may be a number other than seven. Alternatively, the output of the light source 21 is controlled based on the illumination light correction coefficient in two or more regions and the scanning timing signals in the main scanning direction Dh and the sub-scanning direction Dv of the two-dimensional scanning output from the two-dimensional scanning control unit 31. can do.

  In the above description, the case where the image display area 11c of the liquid crystal panel 11 is divided into 12 areas of 4 columns and 3 rows has been described, but other area dividing means, for example, when divided into 24 areas of 6 columns and 4 rows. For example, the number of other regions may be used. The shape of the row area is not limited to a rectangle.

  As described above, the liquid crystal display device according to the first embodiment has two scanning timing signals in the main scanning direction Dh and the sub-scanning direction Dv of the two-dimensional scan output from the two-dimensional scan control unit 31, one signal. Alternatively, an image with high contrast can be obtained by controlling the light emission intensity of the light beam based on the illumination light correction coefficient in the low gradation level region of the two or more regions.

  In addition, the liquid crystal display device according to Embodiment 1 can achieve energy saving because the output of the light source 21 is controlled to be low when displaying a dark image.

Embodiment 2. FIG.
FIG. 6 is a diagram showing the intensity I of the light beam from the light source 21 at the timing when each region is illuminated with a light spot in the liquid crystal display device according to the second embodiment. In FIG. 6, 11c represents an image display area of the liquid crystal display panel, E1 to E12 represent areas divided in the image display area, P1 to P7 represent positions in the sub-scanning direction Dv of the inspection position, and I ₂₁ ˜I ₂₇ shows a change in the light emission intensity of the light source 11 on the image display area 11c (that is, a change in the illumination light correction coefficient used) in a coordinate system in which the horizontal axis is Dh and the vertical axis is the intensity I. In the second embodiment, as shown in FIG. 6, the light emission intensity control unit 22 controls the light emission intensity of the light beam L0 from the light source 21 when the light spot scans two or more regions ( When two or more regions are straddled), it is performed based on the illumination light correction coefficient of the region having the highest gradation level among the two or more regions. In the description of the second embodiment, FIG. 1 to FIG. 4 are also referred to. The liquid crystal display device according to the second embodiment is different from the liquid crystal display device according to the first embodiment in that emphasis is placed on displaying bright images brighter. Except for this point, the liquid crystal display device according to the second embodiment is the same as the liquid crystal display device according to the first embodiment.

First, the main scanning of the first line (scanning position P1) in FIG. 6 will be described. The area E1, the area E2, the area E3, and the area E4 that are illuminated in the main scanning of the first line (scanning position P1) have the lowest gradation level, and therefore the illumination that turns off the light beam L0 from the light source 21 A light correction coefficient (illumination light correction coefficient in the areas E1, E2, E3, and E4) is selected. As a result, as shown in FIG. 6, the intensity I ₂₁ of the light beam L0 from the light source 21 in the main scanning of the first line (scanning position P1) maintains zero.

The main scanning of the second line (scanning position P2) in FIG. 6 will be described. The area E1, the area E2, the area E3, and the area E4, which are illuminated by the main scanning of the second line (scanning position P2), have the lowest gradation level, so that the light beam L0 from the light source 21 is turned off. A light correction coefficient (illumination light correction coefficient in the areas E1, E2, E3, and E4) is selected. As a result, as shown in FIG. 6, the intensity I ₂₂ of the light beam L0 from the light source 21 in the main scanning of the second line (scanning position P2) is maintained zero.

The main scanning of the third line (scanning position P3) in FIG. 6 will be described. The areas illuminated by the light spot in the third line (scanning position P3) are areas E1, E5, areas E2, E6, areas E3, E7, and areas E4, E8. Further, in the middle of the movement of the light spot from the regions E1 and E5 to the regions E2 and E6, there is a period in which illumination is performed across the regions E1, E5, E2, and E6. In the middle of the movement of the light spot from the areas E2 and E6 to the areas E3 and E7, there is a period in which illumination is performed across the areas E2, E6, E3 and E7. Further, in the middle of the movement of the light spot from the areas E3, E7 to the areas E4, E8, there is a period of illumination across the areas E3, E7, E4, E8. In the second embodiment, when the light spot moves across two or more regions, the intensity of the light beam is based on the illumination light correction coefficient of the region having the highest gradation level among the two or more regions. Adjustments are made. As a result, as shown in FIG. 6, the intensity _{I 23} of the light beam L0 from the light source 21 in the main scanning of the third line (scanning position P3), the portion crossing over the area E1, E5, E2, E6, area E2 , E6, and higher in a portion straddling regions E2, E6, E3, E7, a portion straddling regions E3, E7, and a portion straddling regions E3, E7, E4, E8.

The main scanning of the fourth line (scanning position P4) in FIG. 6 will be described. The areas illuminated by the light spot in the fourth line (scanning position P4) are the areas E5, E6, E7, and E8. Further, in the middle of the movement of the light spot from the region E5 to the region E6, there is a period in which illumination is performed across the regions E5 and E6. Further, in the middle of the movement of the light spot from the region E6 to the region E7, there is a period in which illumination is performed across the regions E6 and E7. Further, in the middle of the movement of the light spot from the region E7 to the region E8, there is a period in which illumination is performed across the regions E7 and E8. In the second embodiment, when the light spot moves across two or more regions, the intensity of the light beam is based on the illumination light correction coefficient of the region having the highest gradation level among the two or more regions. Adjustments are made. As a result, as shown in FIG. 6, the intensity I ₂₄ of the light beam L0 from the light source 21 in the main scanning of the fourth line (scanning position P4) becomes high in the region E6 and in the region E6. Further, the height is further increased in the portion straddling the regions E6 and E7, in the region E7, and in the portion straddling the regions E7 and E8.

The main scanning of the fifth line (scanning position P5) in FIG. 6 will be described. The areas illuminated by the light spot in the fifth line (scanning position P5) are areas E5 and E9, areas E6 and E10, areas E7 and E11, and areas E8 and E12. Further, in the middle of the movement of the light spot from the areas E5 and E9 to the areas E6 and E10, there is a period of illumination across the areas E5, E9, E6 and E10. Further, in the middle of the movement of the light spot from the regions E6 and E10 to the regions E7 and E11, there is a period in which illumination is performed across the regions E6, E10, E7, and E11. Further, in the middle of the movement of the light spot from the areas E7, E11 to the areas E8, E12, there is a period of illumination across the areas E7, E11, E8, E12. In the second embodiment, when the light spot moves across two or more regions, the intensity of the light beam is based on the illumination light correction coefficient of the region having the highest gradation level among the two or more regions. Adjustments are made. As a result, the intensity I ₂₅ of the light beam L0 from the light source 21 in the main scanning of the fifth line (scanning position P5), as shown in FIG. 6, is a portion straddling regions E5, E9, E6, E10, region E6. , E10, and higher in a portion straddling regions E6, E10, E7, E11, a portion straddling regions E7, E11, and a portion straddling regions E7, E11, E8, E12.

The main scanning of the sixth line (scanning position P6) in FIG. 6 will be described. The regions illuminated by the light spot in the main scanning of the sixth line (scanning position P6) are region E9, region E10, region E11, and region E12. In the middle of the movement of the light spot from the region E9 to the region E10, there is a period in which illumination is performed across the regions E9 and E10. Further, in the middle of the movement of the light spot from the region E10 to the region E11, there is a period in which illumination is performed across the regions E10 and E11. Further, in the middle of the movement of the light spot from the region E11 to the region E12, there is a period in which illumination is performed across the regions E11 and E12. In the second embodiment, when the light spot moves across two or more regions, the intensity of the light beam is based on the illumination light correction coefficient of the region having the highest gradation level among the two or more regions. Adjustments are made. As a result, as shown in FIG. 6, the intensity I ₂₆ of the light beam L0 from the light source 21 in the main scanning of the sixth line (scanning position P6) is a portion straddling the regions E9 and E10, in the region E10, and in the region E11. Of these, the height is increased in a portion across the regions E11 and E12.

The main scanning of the seventh line (scanning position P7) in FIG. 6 will be described. The region illuminated by the light spot in the main scanning of the seventh line (scanning position P7) is the boundary in the horizontal direction of the region E9, the region E10, the region E11, and the region E12. In the middle of the movement of the light spot from the region E9 to the region E10, there is a period in which illumination is performed across the regions E9 and E10. Further, in the middle of the movement of the light spot from the region E10 to the region E11, there is a period in which illumination is performed across the regions E10 and E11. Further, in the middle of the movement of the light spot from the region E11 to the region E12, there is a period in which illumination is performed across the regions E11 and E12. In the second embodiment, when the light spot moves across two or more regions, the intensity of the light beam is based on the illumination light correction coefficient of the region having the highest gradation level among the two or more regions. Adjustments are made. As a result, as shown in FIG. 6, the intensity I ₂₇ of the light beam L0 from the light source 21 in the main scanning of the seventh line (scanning position P7) crosses the regions E9 and E10, the region E10, and the region E11. Of these, the height is increased in a portion across the regions E11 and E12.

  As described above, the liquid crystal display device according to the second embodiment has two scanning timing signals in the main scanning direction Dh and the sub-scanning direction Dv of the two-dimensional scan output from the two-dimensional scan control unit 31, one signal. Alternatively, an image with high contrast can be obtained by controlling the light emission intensity of the light beam based on the illumination light correction coefficient in a region having a high gradation level among two or more regions.

  In addition, the liquid crystal display device according to the second embodiment can realize energy saving because the output of the light source 21 is controlled to be low when displaying a dark image.

It is a figure which shows schematically the structure and operation | movement of a liquid crystal display device which concern on Embodiment 1 and 2 of this invention. FIG. 3 is a diagram schematically showing a configuration of an optical system and a configuration of a control system of a liquid crystal display device according to Embodiments 1 and 2. (A) is a figure for demonstrating the area | region which divides | segments the image display area | region of a liquid crystal panel in the liquid crystal display device which concerns on Embodiment 1 and 2, (b) scans the area | region to divide | segment and a light spot. It is a figure for demonstrating the relationship with the position to perform. FIG. 4 is a diagram for explaining an input video signal in a region that divides an image display region of a liquid crystal panel in the liquid crystal display devices according to the first and second embodiments. FIG. 4 is a diagram showing the intensity of a light beam from a light source at a timing when each region is illuminated with a light spot in the liquid crystal display device according to Embodiment 1. FIG. 10 is a diagram illustrating the intensity of a light beam from a light source at a timing when each region is illuminated with a light spot in the liquid crystal display device according to Embodiment 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Liquid crystal panel, 11a Surface of liquid crystal panel, 11b Back surface of liquid crystal panel, 11c Image display area of liquid crystal panel, 12 Liquid crystal drive signal generation part, 13 Liquid crystal drive part, 20 Light beam emission part, 21 Light source, 22 Light emission intensity control part , 23 divided area control unit, 30 two-dimensional scan drive unit, 31 two-dimensional scan control unit, A1 liquid crystal drive signal, A2 illumination light correction coefficient, A3 scan timing signal, Dh main scan direction, Dv sub-scan direction, E1 to E12 divided regions, _I, the intensity of _{I 11 ~I 17, I 21 ~I} 27 light beam, P1 to P7 scanning position, S1 light spot scanning start position.

Claims (3)

LCD panel,
Liquid crystal drive signal generating means for generating a liquid crystal drive signal based on the input video signal;
Liquid crystal driving means for driving the liquid crystal panel based on the liquid crystal driving signal;
A light source that emits a light beam;
Two-dimensional scanning drive means for deflecting the light beam and two-dimensionally scanning a light spot formed by the light beam in the main scanning direction and the sub-scanning direction on the back surface of the image display area of the liquid crystal panel;
Two-dimensional scanning control means for supplying scanning timing signals in the main scanning direction and sub-scanning direction of the light spot to the two-dimensional scanning driving means;
A divided area control means for dividing the image display area of the liquid crystal panel into a plurality of areas and outputting an illumination light correction coefficient based on the input video signal for each of the areas;
Emission intensity control means for controlling the emission intensity of the light beam based on the illumination light correction coefficient for each region,
The control of the light emission intensity of the light beam by the light emission intensity control means is performed by controlling the illumination light correction coefficient in one area scanned by the light beam in the plurality of areas or the light in the plurality of areas. Based on the illumination light correction coefficient of any one of the two or more areas scanned by the beam,
The switching timing of the illumination light correction coefficient used for controlling the light emission intensity of the light beam by the light emission intensity control means is determined based on the scanning timing signal from the two-dimensional scanning control means. Display device.   The light intensity of the light beam is controlled by the light intensity control means when the light spot scans two or more areas of the plurality of areas. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is performed based on the illumination light correction coefficient in the lowest level region.   The light intensity of the light beam is controlled by the light intensity control means when the light spot scans two or more areas of the plurality of areas. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is performed based on the illumination light correction coefficient in a region having the highest level.

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