JP2015132784A - image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image display device capable of maintaining the constant luminance and luminescent color of a backlight light source part while suppressing unevenness of the luminance and the color.SOLUTION: An image display device 10 includes: an image display part 17; a backlight light source part 15; a light detection part 13; a light source control part 14; and a timing generation part 11. Luminescence driving signals P1 to Pn generated by the timing generation part 11 sequentially light the light sources of a plurality of division light source areas 151 to 15n of the backlight light source part 15 in response to the scanning in the image display part 17 while, during a detection period in which a light detection gate signal GA enables the detection of the light detection part 13, lighting all the light sources of the plurality of division light source areas 151 to 15n of the backlight light source part 15, and during a plurality of other detection periods, lighting the light source of a division light source area selected from the plurality of division light source areas of the backlight light source part 15, and turning off the light sources of the other division light source areas.

Description

  The present invention relates to an image display device including an image display unit and a backlight light source unit.

  When an image is displayed on a liquid crystal panel as an image display unit, a process for giving the liquid crystal a desired light transmittance by applying a driving voltage corresponding to the gradation (luminance) indicated by the input image signal to the liquid crystal. (Image rewriting process) is repeated for each frame. Since a certain amount of time is required until the light transmittance of the liquid crystal reaches a desired value after the drive voltage is applied to the liquid crystal, the liquid crystal panel is not suitable for displaying a moving image that changes quickly. . Therefore, the backlight light source unit of the liquid crystal panel is divided into a plurality of areas, and the light sources in the plurality of areas are sequentially turned on and off according to the timing of the image rewriting process performed in synchronization with the input image signal ( Technologies for performing backlight scanning have been proposed.

  In this technique, after the driving voltage corresponding to the input image signal is applied to the liquid crystal, the light source in the corresponding area is kept off until the light transmittance of the liquid crystal approaches a desired value, and the light transmission of the liquid crystal is continued. The control of turning on the light source in the corresponding area when the rate approaches a desired value is repeatedly performed for a plurality of areas in each frame of the input image signal. The liquid crystal display device that performs such control is configured to turn on the light source in the corresponding region in a period from when the driving voltage corresponding to the input image signal is applied to the liquid crystal until the light transmittance of the liquid crystal approaches a desired value. Since the image is turned off and no image is displayed, a moving image with less blur can be displayed even when displaying a moving image that changes quickly.

  On the other hand, the luminance of the light source provided in the backlight light source unit changes according to the temperature and gradually changes with the passage of time. Further, in the backlight light source unit having light sources that emit light of different colors, when the luminance of the light source of each color changes, the ratio (light quantity balance) of the light amount of each color emitted from the light source of each color changes, The color temperature when a white image is displayed changes. Furthermore, when a change in the luminance of the light source of each color or a change in the ratio of the amount of light of each color emitted from the light source of each color occurs in a part of the screen, luminance unevenness or color unevenness appears in the image displayed on the screen. May occur.

  Patent Document 1 includes three types of light sources with different emission colors for illuminating the liquid crystal panel from the back, and three types of optical sensors corresponding to the emission colors of the three types of light sources, and an image displayed on the liquid crystal panel. A liquid crystal display device has been proposed in which three types of light sources are operated so that the white balance is equal to a set value.

  Patent Document 2 discloses a light emitting unit having a light emitting surface including a plurality of regions, a detection unit that detects a feature amount of a video signal, and a light emission luminance value of the plurality of regions based on the detected feature amount. Providing a backlight light source unit (light source device) that performs local contrast control, including a determination unit that determines each and a drive unit that updates light emission states in a plurality of regions based on the determined light emission luminance values Yes.

Japanese Patent Laid-Open No. 11-295589 (for example, claim 1 and FIG. 1) Japanese Patent Laying-Open No. 2011-118278 (for example, claim 1 and FIG. 3)

  However, in the backlight light source unit having a light emitting surface including a plurality of regions, when the light sources of the plurality of regions are controlled to sequentially emit light in a short period in synchronization with the image, The optical sensor (light detection unit) detects not only the light emitted from the light source in the detection target area but also the light emitted in the adjacent area, so that the amount of light emitted from each of the light sources in the plurality of areas can be accurately determined. Cannot be detected. Therefore, the image display device cannot appropriately control the light emission amounts of the light sources in the plurality of regions of the backlight light source unit based on the detection value of the optical sensor. For this reason, in a conventional image display device that sequentially emits light from a plurality of regions of a backlight light source unit, it is difficult to keep the luminance or emission color of the backlight light source unit constant, and uneven brightness or color unevenness occurs. There was a problem that there was.

  Accordingly, the present invention has been made to solve the above-described problems of the prior art, and can maintain the luminance and emission color of the backlight light source unit at a constant level, and suppress luminance unevenness or color unevenness. An object of the present invention is to provide an image display device capable of performing the above.

  An image display device according to the present invention sequentially scans the screen in a predetermined direction in synchronization with a screen and an input image signal, and changes the light transmittance of the screen according to the input image signal. An image display unit including a plurality of divided light source regions, a backlight light source unit that emits light from the plurality of divided light source regions toward the screen, and light emitted from the backlight light source unit A light detection unit that detects a light intensity and outputs a light detection value indicating the light intensity; and a light emission intensity of each of the plurality of divided light source regions based on the light detection value output from the light detection unit A light source control unit that controls the light source, a light emission drive signal that causes the backlight light source unit to emit light based on a reference signal included in the input image signal, and light detection that enables detection of the light intensity by the light detection unit Gate signal and And the light emission drive signal generated by the timing generation unit sequentially turns on the light sources of the plurality of divided light source regions of the backlight light source unit according to the scanning in the image display unit. In addition, in a detection period in which the light detection gate signal enables detection of the light detection unit, all of the light sources in the plurality of divided light source regions of the backlight light source unit are turned on, and the light detection gate signal In another plurality of detection periods in which detection of the detection unit is enabled, the light source of the one divided light source region selected from the plurality of divided light source regions of the backlight light source unit is turned on, and the other divided light sources The light source in the area is turned off.

  In the present invention, detection of light emitted from the backlight light source unit is performed during a period in which all of the light sources of the plurality of divided light source regions are turned on to obtain the first detection value, and from the backlight light source unit The emitted light is detected during each period in which the light sources included in each of the plurality of divided light source regions are sequentially turned on to obtain a plurality of second detection values, and the light source control unit includes the first detection values and Based on the plurality of second detection values, the light emission intensity of each light source in the plurality of divided light source regions of the backlight light source unit is controlled. Therefore, according to the present invention, it is possible to accurately detect the light intensity for controlling the emission intensity of each divided light source region of the backlight light source unit, and based on the accurate detection value, the backlight light source unit Control for keeping the luminance or emission color constant and control for suppressing luminance unevenness or color unevenness can be performed.

1 is a block diagram schematically showing a configuration of an image display device according to Embodiment 1 of the present invention. (A) And (b) is the front view and side view which show roughly arrangement | positioning of the backlight light source part of the image display apparatus which concerns on Embodiment 1, a light-guide plate, and a photon detection part. 3 is a front view schematically showing a screen area of an image display unit of the image display apparatus according to Embodiment 1. FIG. 6 is a timing chart showing temporal changes in the period of each frame, the display image of each frame, and the light transmittance in a plurality of screen areas of the liquid crystal panel in the image display apparatus according to Embodiment 1; In the image display device according to Embodiment 1, the period of each frame, the display image of each frame, the temporal change in light transmittance in a plurality of screen regions of the liquid crystal panel, and the light emission drive signal (high) of the light sources in the plurality of divided light source regions It is a timing chart which shows a level period. In the image display device according to Embodiment 1, the period of each frame, the display image of each frame, the temporal change in light transmittance in a plurality of screen regions of the liquid crystal panel, and the light emission drive signal (high) of the light sources in the plurality of divided light source regions It is a timing chart which shows the change of the length of a (level period). In the image display device according to Embodiment 1, the period of each frame, the display image of each frame, the temporal change in light transmittance in a plurality of screen regions of the liquid crystal panel, and the light emission drive signal (high) of the light sources in the plurality of divided light source regions It is a timing chart which shows the phase shift of a level period. 4 is a timing chart showing a period of each frame, a light emission drive signal (high level period) of a light source in a plurality of divided light source regions, and a detection gate of a light detection unit in the image display device according to the first embodiment. The period of each frame in the image display device of the comparative example, the temporal change of the light transmittance in the plurality of screen areas of the liquid crystal panel, the light emission drive signal (high level period) of the light sources in the plurality of divided light source areas, and the detection of the light detection unit It is a timing chart which shows a gate. The period of each frame in the image display device of the comparative example, the temporal change of the light transmittance in the plurality of screen areas of the liquid crystal panel, the light emission drive signal (high level period) of the light sources in the plurality of divided light source areas, and the detection of the light detection unit It is a timing chart which shows a gate. 4 is a timing chart showing a period of each frame, a light emission drive signal (high level period) of a light source in a plurality of divided light source regions, and a detection gate of a light detection unit in the image display device according to the first embodiment. It is a block diagram which shows schematically the structure of the image display apparatus which concerns on Embodiment 2 of this invention. The period of each frame, the display image of each frame, the vertical synchronization signal, the image valid signal, the temporal change in light transmittance in a plurality of screen areas of the liquid crystal panel, and the plurality of divided light source areas in the image display device according to the second embodiment It is a timing chart which shows the light emission drive signal (high level period) of this light source. It is a block diagram which shows schematically the structure of the image display apparatus which concerns on Embodiment 3 of this invention. (A) And (b) is the front view and side view which show roughly arrangement | positioning of the backlight light source part of the image display apparatus which concerns on Embodiment 3, a light-guide plate, and a photon detection part. (A) And (b) is a figure which shows operation | movement of the image display apparatus which concerns on Embodiment 3. FIG. 14 is a timing chart showing a period of each frame, a display image of each frame, a vertical synchronization signal, and a light emission drive signal (high level period) of light sources in a plurality of divided light source regions in the image display device according to the third embodiment.

<1> First Embodiment
<1-1> Configuration of the first embodiment.
FIG. 1 is a block diagram schematically showing a configuration of an image display apparatus 10 according to Embodiment 1 of the present invention. The image display device 10 is, for example, a liquid crystal display device, and is provided with an image display unit 17 such as a transmissive liquid crystal panel, and a back light source that irradiates light toward the back surface of the image display unit. Device 10a. As shown in FIG. 1, the image display apparatus 10 according to the first embodiment includes a timing generation unit 11, a reference value recording unit 12, a light detection unit 13 having one or more photosensors, and a light source control unit. 14, a backlight light source unit 15 having a plurality of light sources, and a light guide plate 16 as a light guide unit that emits light emitted from the backlight light source unit 15 toward the back surface of the image display unit 17. . The timing generation unit 11, the reference value recording unit 12, the light detection unit 13, the light source control unit 14, the backlight light source unit 15, and the light guide plate 16 constitute a backlight light source device 10a. The backlight light source unit 15 is divided into a plurality of regions (hereinafter referred to as “divided light source regions”), that is, n divided light source regions (n is an integer of 2 or more). Each has one or more light sources. The image display apparatus 10 also includes a control unit that controls the operation of the entire apparatus including the configurations 11 to 15 and 17.

  In the image display device 10 according to the first embodiment, as shown by the white arrow in FIG. 1, the light emitted from the backlight light source unit 15 enters the light guide plate 16, and the light intensity distribution is made uniform. The planar light is emitted toward the back surface of the image display unit 17. The light guide plate 16 is, for example, a thin plate-like optical member, and is a light emitting surface (light emitting surface) (16a in FIG. 2B) 16a facing the back surface of the image display unit 17, and a light diffusion surface on the opposite side. (16b in FIG. 2B). In parallel with the process in which the image display unit 17 changes the light transmittance for each pixel in accordance with the input image signal I1 (image rewriting process), from the light emitting surface of the light guide plate 16 (16a in FIG. 2B). The back surface of the image display unit 17 is irradiated with the emitted light (that is, planar light with a uniform light intensity distribution). By such an operation, an image corresponding to the input image signal I1 is displayed on the image display unit 17.

  The input image signal I1 is input to the image display unit 17. In addition, the image reference signal B0 included in the input image signal I1 is input to the timing generation unit 11. In the first embodiment, the case where the image reference signal B0 is the vertical synchronization signal V included in the input image signal I1 will be described. The input image signal I1 may be input to the timing generation unit 11, and the timing generation unit 11 may extract the image reference signal B0 from the input image signal I1.

  The timing generation unit 11 generates a light detection gate signal GA that causes the light detection unit 13 to detect the light intensity of the backlight light source unit 15 based on the image reference signal B0, and uses the light detection gate signal GA as the light detection unit 13. To supply. The timing generation unit 11 controls the operation of the light detection unit 13 using the light detection gate signal GA.

  Further, the timing generation unit 11 generates light emission drive signals P1 to Pn for turning on and off the light sources of the plurality of divided light source regions of the backlight light source unit 15 based on the image reference signal B0, and the generated light emission drive signals. P1 to Pn are supplied to the backlight light source unit 15. That is, the timing generation unit 11 controls the light sources of a plurality (n) of divided light source regions of the backlight light source unit 15 independently for each divided light source region using the light emission drive signals P1 to Pn. The light emission drive signals P <b> 1 to Pn are drive signals for n divided light source regions of the backlight light source unit 15.

  The reference value recording unit 12 holds a reference light detection value MD and a reference light emission intensity value ME set in advance, and appropriately outputs these values to the light source control unit 14. The number of reference light detection values MD held is the number of light sensors installed in the light detection unit 13, the number of light colors that can be detected by the light sensor, and the number n of divided light source regions in the backlight light source unit 15. The number is equal to the number of combinations of n + 1, which is the total number of the light sources in the divided light source regions when all the light sources are turned on. The number of reference emission intensity values ME held is equal to the number of combinations of the number of divided light source regions of the backlight light source unit 15 and the number of colors of the light sources of the backlight light source unit 15.

  Next, a method for determining the reference light detection value MD and the reference light emission intensity value ME to be held in the reference value recording unit 12 will be described. First, a reference signal, for example, a signal (all white signal) in which all colors have the maximum gradation in all pixels is input to the image display device 10 according to the first embodiment and operated, and the luminance installed outside. The luminance is measured by a meter or a surface luminance meter, and the emission intensity value of each color of the light source is adjusted for each of the divided light source regions so that the output light of the image display unit 17 becomes a target luminance value, white balance, color temperature, etc. To do. Further, the light emission intensity value of each light source of the plurality of divided light source regions is adjusted so that the brightness of the screen of the image display unit 17 or the color of the screen is uniform, that is, the brightness unevenness or the color unevenness is eliminated.

  Thereafter, the reference value recording unit 12 is a light in a state where all the light sources of the plurality of divided light source regions of the backlight light source unit 15 are turned on when the output light from the screen of the image display unit 17 is adjusted to a target value. The light detection value of the detection unit 13 is held as a reference light detection value MDa, and the light emission intensity value input to the light source of each divided light source region is held as a reference light emission intensity value MEn.

  Next, the reference value recording unit 12 has the light source of one divided light source region among the n divided light source regions of the backlight light source unit 15 in a state where the output light of the image display unit 17 is adjusted to a target value. Is turned on and the light sources of the other divided light source regions are turned off, and the light detection values n of the light detection unit 13 when only the light sources of the respective divided light source regions turned on are turned on are held as reference light detection values MDn. .

  Since the luminance of the light source changes according to the temperature or gradually changes with time, the reference value recording unit 12 uses the reference light detection value MD and the reference corresponding to the temperature condition or the cumulative lighting time of the light source. The value of the light emission intensity value ME may be held. For example, the reference emission intensity value ME when the temperature is low and the reference emission intensity value ME when the temperature is high are determined separately and stored in the reference value recording unit 12, and either one is selected according to the detection result of the temperature detection means. By selecting and using, the target color can be converged more quickly. Further, for example, since the light source becomes generally darker as the cumulative time during which the light source is lit increases, a cumulative lighting time holding means for measuring and storing the cumulative lighting time of the light source is provided, and the reference is set according to the increase in the cumulative lighting time. You may comprise so that the value of the reference light detection value MD stored in the value recording part 12 may be reduced. As a specific example, the light emission intensity value E output from the light source control unit 14 to the backlight light source unit 15 is held in the reference value recording unit 12 immediately before the light source of the backlight light source unit 15 is turned off. The control unit 14 may output the light emission intensity value E to the backlight light source unit 15. By determining the reference light detection value MD in this way, it is possible to converge to the target luminance and color more quickly. The changes in the reference light detection value MD and the reference light emission intensity value ME may be determined according to the characteristics of the device used as the light source.

  The reference value recording unit 12 may store and hold the reference light detection value MD and the reference light emission intensity value ME for each target white color or color temperature with respect to the output light from the image display unit 17. By doing in this way, there exists an effect which can switch setting, such as color temperature, by adjustment of the emitted light intensity of a light source.

  Light output from the light guide plate 16 (light generated by the backlight light source unit 15) is input to the light detection unit 13. The light detection unit 13 includes one or more optical sensors so that the light intensity of one or more colors in the light emitted from the light guide plate 16 can be detected. The light detection unit 13 performs a light detection operation for detecting the light intensity of the backlight light source unit 15 only during a period when the light detection gate signal GA output from the timing generation unit 11 is significant, for example, a high (H) level period. . The light detection unit 13 supplies the detected result value as the light detection value D to the light source control unit 14. The light detection value D is, for example, a voltage value proportional to the light intensity of the backlight light source unit 15.

  The light sensor of the light detection unit 13 may be one luminance sensor that can detect the luminance value, or the light amounts of three colors of red (R), green (G), and blue (B). It may be a color light sensor that can be detected (ie, a red (R) color light sensor, a green (G) color light sensor, and a blue (B) color light sensor). As the optical sensor, various types of optical sensors can be used. For example, a sensor using a photoelectric cell, a sensor using a photodiode, or a combination of these and an optical filter may be used. Good. When a color light sensor that detects light of a plurality of colors is used, the same number of light detection values D as the number of light colors to be detected are output.

  Note that the optical sensor of the light detection unit 13 is installed between the light guide plate 16 and the image display unit 17, for example. The installation location of the optical sensor is not particularly limited as long as it can detect the light emitted from the light guide plate 16. The optical sensor may be a single sensor installed at one location, or a plurality of sensors installed at multiple locations. In the first embodiment, when a plurality of optical sensors are installed corresponding to each of the plurality of divided light source regions, the light sources in the divided light source regions corresponding to the installation locations can be controlled. When a plurality of photosensors are installed, the same number of photodetection values D as the number of photosensors are output. In the first embodiment, even with a configuration having only one optical sensor, the light emission color of the backlight light source unit can be kept constant, and luminance unevenness or color unevenness can be suppressed. Further, when a plurality of optical sensors of the light detection unit 13 are installed, the accuracy can be further improved.

  In the initial state, the light source control unit 14 outputs the reference light emission intensity value ME held in the reference value recording unit 12 to the backlight light source unit 15 as the light emission intensity value E. Thereafter, the light source control unit 14 emits light intensity of the backlight light source unit 15 based on the light detection value D detected by the light detection unit 13 and the reference light detection value MD preset in the reference value recording unit 12. A value E is determined for each of the plurality of divided light source regions.

  Specifically, the control of the light source control unit 14 in a state where all the light sources in the plurality of divided light source regions of the backlight light source unit 15 are turned on will be described. The light source control unit 14 corresponds to a state in which the light detection value D of the light detection unit 13 in a state where all the light sources of the plurality of divided light source regions of the backlight light source unit 15 are turned on is stored in the reference value recording unit 12 ( The light emission intensity value E is determined so as to be the same as the reference light detection value MDa in a state where all of the light sources in the plurality of divided light source regions are turned on, and is output to the backlight light source unit 15. Here, the light emission intensity value E is, for example, a current amount, and the backlight light source unit 15 to which the light emission intensity value E is input is configured to emit light with a light amount proportional to the input light emission intensity value E. ing. For example, when the light detection value D when the light sources of the plurality of divided light source regions of the backlight light source unit 7 are all turned on is lower than the reference light detection value MDa in the same state, the light source control unit 14 Each of the emission intensity values E supplied to is controlled to increase uniformly. Conversely, if the light detection value D when all the light sources in the plurality of divided light source regions of the backlight light source unit 7 are turned on is higher than the reference light detection value MDa in the same state, the light source control unit 14 Is controlled so as to uniformly reduce each of the emission intensity values E supplied to. In this way, the light source control unit 14 controls the light detection value D to be substantially equal to the reference light detection value MDa, so that the output light of the backlight light source unit 15 is adjusted to a target value. The state and the state in which all the light sources in the plurality of divided light source regions are turned on can be made the same state.

  Next, control in the state where only the light source of one divided light source region among the plurality of divided light source regions of the backlight light source unit 15 of the light source control unit 14 is turned on will be described. The light source control unit 14 is configured such that the light detection value D of the light detection unit 13 in a state where only the light source of one divided light source region among the plurality of divided light source regions of the backlight light source unit 15 is turned on is the reference light detection value MDk. The light emission intensity value Ek of the lit divided light source region k is determined so as to be the same, and is output to the backlight light source unit 15. Here, k is an integer of 1 to n. For example, the light source control unit 14 uses the light detection value D when only the light source of the divided light source region 151 of the backlight light source unit 15 is turned on as the reference light detection value MD1 when only the light source of the divided light source region 151 is turned on. When it is low, the light emission intensity value E1 of the divided light source region 151 is increased, and the light detection value D is controlled to be the same as the reference light detection value MD1. Conversely, if the light detection value D when only the light source of the divided light source region 151 of the backlight light source unit 15 is turned on is higher than the reference light detection value MD1, the light source control unit 14 emits light intensity E1 of the divided light source region 151. Is controlled to be small. As described above, the light source control unit 14 controls the light detection value D so as to be substantially equal to the reference light detection value MDk, so that the output light of the backlight light source unit 15 is adjusted to a target value, The state in which the light source in one of the divided light source regions is turned on can be made the same state.

  Note that the emission intensity value E output from the light source control unit 14 is output, for example, by the number of the plurality of divided light source regions of the backlight light source unit 15 or the number of light sources of the plurality of divided light source regions. When there are a plurality of colors of light emitted from the light source and there are a plurality of colors of light detected by the optical sensor, the color of each color is set to be equal to the reference light detection value MD with respect to the light detection value D of the optical sensor of each color. The emission intensity value E is controlled. Further, in the comparison between the reference light detection value MD and the light detection value D, how close the values are considered to be approximately equal is determined at the time of designing in consideration of the balance between desired luminance or color change and adjustment convergence time. Just decide.

  In the above description, the light source control unit 14 determines the light emission intensity of the backlight light source unit 15 based on the light detection value D detected by the light detection unit 13 and the preset reference light detection value MD. An example of controlling has been described. However, the present invention is not limited to such a form, and the light source control unit 14 uses the predetermined expression from the light detection value D detected by the light detection unit 13 to determine the light emission intensity value E of the backlight light source unit 15. And the backlight light source unit 15 may be controlled so that the calculated emission intensity value E is obtained.

  The backlight light source unit 15 includes n divided light source regions, and the number of colors of the light sources provided in each of the n divided light source regions includes one or more colors. Each light source of the plurality of divided light source regions of the backlight light source unit 15 corresponds to the light emission intensity value E output from the light source control unit 14 for the period indicated by the light emission drive signals P1 to Pn output from the timing generation unit 11. Emits light. In the following description, the light source in the divided light source region may be turned on and off, and the light source in the divided light source region may be described as turned on and off.

  The backlight light source unit 15 may be composed of one type of white light source, or a combination of light sources of a plurality of colors, for example, a three-color light source of red (R), green (G), and blue (B). Or a combination of two color light sources of cyan (C) and red (R) to generate white light. Various types of light emitters can be used. For example, a light emitting diode (LED), a laser, an organic electroluminescence (organic EL), a combination thereof, or a combination thereof with a fluorescent material. There may be.

  The light sources of the plurality of divided light source regions of the backlight light source unit 15 are configured to be controlled independently for each of the plurality of divided light source regions. The backlight light source unit 15 may be disposed directly below the image display unit 17, or may be disposed at the left and right ends or the upper and lower ends of the liquid crystal panel.

  The backlight light source unit 15 emits pulses by the light emission drive signals P1 to Pn, and the light emission intensity is variable by the light emission intensity value E. Specifically, the light emission drive signals P1 to Pn are configured by the same number of signals as the number of divisions of the backlight light source unit (that is, the number n of divided light source regions). During the period indicated by the corresponding light emission drive signals P1 to Pn, the light is lit with the light amount indicated by the corresponding light emission intensity value E. For example, the light sources in each divided light source region are controlled to be turned on during the high (H) level period of the light emission drive signals P1 to Pn and controlled to be turned off during the low (L) level period. The light emission intensity value E may be composed of a combination of n as the number of divided light source regions and m colors as the number of light source colors, that is, n × m, or m equal to the number of light source colors. It may be configured by n or may be configured by n which is the number of divided light source regions.

  Light emitted from the backlight light source unit 15 enters the light guide plate 16. The light guide plate 16 diffuses the incident light uniformly in a planar shape in a predetermined light guide region, and then emits the light uniformly diffused in a planar shape toward the back surface of the image display unit 17. Further, when the backlight light source unit 15 is composed of a combination of light sources of a plurality of colors such as red (R), green (G), and blue (B), the light guide plate 16 has a plurality of light guide plates 16. It has the function of mixing color light to make white light. Although the backlight light source unit 15 is divided into n divided light source regions, the light guide plate 16 does not normally need to have a physically divided structure, and uses a single plate-like optical member. And has a structure that diffuses light throughout. That is, the n light guide regions of the light guide plate 16 are a concept indicating a range corresponding to the n divided light source regions of one light guide plate 16, and are not separate members but an integrated optical member. .

  The image display unit 17 is, for example, a transmissive liquid crystal panel in which color filters are arranged. When the input image signal I1 is input to the screen drive unit 17b of the image display unit 17, the input image is scanned sequentially from the top to the bottom (predetermined direction) of the screen 17a in synchronization with the input image signal I1. In accordance with the gradation of the signal I1, the light transmittance of the light from the back surface to the front surface is changed for each pixel. Thus, an image based on the input image signal I1 is displayed on the image display unit 17.

  2A and 2B are a front view and a side view schematically showing the arrangement of the backlight light source unit 15, the light guide plate 16, and the light detection unit 13 of the image display apparatus 10 according to the first embodiment. is there. In the example shown in FIGS. 2A and 2B, a light guide plate 16 that is a kind of light guide is provided on the back of the image display unit 17, and on the left side of the light guide plate 16 (the left end of the image display unit 17). A backlight light source unit 15 is disposed. The backlight light source unit 15 is disposed at the left end of the light guide plate 16 in FIG. 2, but may be disposed directly below the light guide plate 16. Here, the light detection unit 13 is disposed at the center of the light guide plate 16 in plan view, but may be disposed at any location as long as it is disposed between the light guide plate 16 and the image display unit 17.

  2A and 2B, the backlight light source unit 15 is a light source that can be controlled independently in each of the n divided light source regions arranged in the vertical direction (in FIG. 2A, Red (R), green (G), and blue (B) light sources are arranged. The light emitted from the backlight light source unit 15 is diffused by the light guide plate 16 and guided from end to end of the image display unit 17 in plan view. During this time, light from the three color light sources of red (R), green (G), and blue (B) is mixed to become white light. The diffused light is detected by the light detector 13. For example, in FIG. 2A, Er_1, Eg_1, and Eb_1 mean the emission intensity values E of the three color light sources of red, green, and blue in the upper divided light source region in FIG. 2A, and Dr, Dg, Db means a light detection value D of three colors of red, green, and blue.

  The light guide plate 16 has a function of diffusing light so that light unevenness does not occur over a wide range. The light emitted from the light source in one divided light source region of the backlight light source unit 15 causes only one corresponding light guide region in the light guide plate 16 (the range indicated by the dotted line shown on the light guide plate 16 in FIG. 2) to shine. Instead, the adjacent light guide regions in the light guide plate 16 or light guide regions further away from the light guide plate 16 are slightly lit. In other words, one light guide region of the light guide plate 16 is not only the light emitted from the light source of the corresponding one divided light source region, but also the light source of the divided light source region adjacent thereto or the light source of the further separated light source region. It will shine with the amount of light that combines all of the light emitted from.

<1-2> Operation of the first embodiment.
Next, a more detailed operation of the image display device 10 according to the first embodiment will be described. FIG. 3 is a diagram illustrating a screen 17 a of the image display unit 17 of the image display device 10. Here, as shown in FIG. 3, the screen 17 a of the image display unit 17 is not divided in the horizontal direction but is divided into n in the vertical direction. The n screen areas 17a1 to 17an obtained by this division correspond to the divided light source areas 151 to 15n of the backlight light source unit 15, and the lighting and extinguishing of the light sources in the respective screen areas are independent. And can be controlled. In addition, when the screen 17a of the image display unit 17 is also divided in the horizontal direction, the light sources of the corresponding group of divided light source regions so that the group of screen regions having the same position in the vertical direction are turned on at the same timing. What is necessary is just to control lighting of.

  FIG. 4 shows temporal changes in the period T of each frame in the image display apparatus 10 according to the first embodiment, the display image of each frame, and the light transmittance in a plurality of screen regions of the liquid crystal panel as the image display unit 17 (liquid crystal It is a timing chart which shows (response). In the example of FIG. 4, the input image signal I1 input to the image display unit 17 is a signal for alternately displaying an all white screen and an all black screen for convenience of explanation. In FIG. 4, the horizontal axis indicates time, and the dotted line indicates the change in the light transmittance of the liquid crystal of the image display unit 17.

  In FIG. 4, the change of the light transmittance of the liquid crystal is shown for each screen area from the upper part of the screen of the image display unit 17 to the lower part of the screen. Point A1 indicates the timing at which gradation writing of the first frame starts in the screen area at the top of the screen, and point B1 indicates the timing at which gradation writing of the second frame starts in the same area. Point A2 indicates the timing when writing of one frame of gradation starts in the second screen area from the top, and point B1 indicates the timing of starting writing of two frames of gradation in the same area. The same applies to the points An and Bn. In the display image of FIG. 4, for the sake of convenience of explanation, an all-white screen and an all-black screen are alternately displayed, so that points A1 to An and points B1 to Bn for all screen regions are aligned. Yes.

  Next, gradation writing (image writing processing) in each screen area will be described in detail. First, writing to the liquid crystal in the screen area at the top of the screen will be described. At the timing of point A1 in FIG. 4, the first frame of white (strictly speaking, the gradation corresponding to the area) is written in the liquid crystal in the screen area at the top of the screen. Since the liquid crystal is written in white, the light transmittance gradually increases in response. Thereafter, black of the second frame is written into the liquid crystal in the screen area at the top of the screen at the timing of point B1. Since the liquid crystal is written black, the light transmittance gradually decreases in response. As shown in FIG. 4, the liquid crystal responds sufficiently immediately before the point B1, that is, immediately before switching from the first frame to the second frame, and is close to the target light transmittance corresponding to the white of the first frame. . This is an example in the case where the response of the liquid crystal is slow. If the response of the liquid crystal is sufficiently fast, it converges before that and the light transmittance is constant. Thus, if the light source of the divided light source region corresponding to the screen region at the top of the screen is turned on immediately before the point B1 at which the liquid crystal sufficiently responds, only the state of the liquid crystal that has reached the target gradation can be displayed. it can.

  Next, writing to the liquid crystal in the screen area at the bottom of the screen will be described. At the timing of the point An in FIG. 4, the white of the first frame (strictly, the gradation corresponding to the screen area) is written in the liquid crystal in the screen area at the bottom of the screen. Since the liquid crystal panel is scanned from the top to the bottom, the point An indicating the writing timing in the screen area at the bottom of the screen is delayed from the point A1 indicating the writing timing at the top of the screen. Thereafter, black of the second frame is written into the liquid crystal in the divided light source region at the bottom of the screen at the timing of the point Bn. At the bottom of the screen, like the top of the screen, the liquid crystal responds sufficiently immediately before the point Bn, that is, immediately before switching from the first frame to the second frame, and the desired light transmittance corresponding to the white of the first frame is achieved. It ’s close. Thus, if the light source of the divided light source region corresponding to the screen region at the bottom of the screen is turned on immediately before the point Bn at which the liquid crystal sufficiently responds, only the state of the liquid crystal that has reached the target gradation can be displayed. it can.

  As described above, if the light source in the corresponding divided light source region is controlled to be turned on immediately before switching from the first frame to the second frame, it is possible to display an image in a state where the liquid crystal is sufficiently responsive. That is, it is appropriate to emit light from the corresponding divided light source regions immediately before the points B1 to Bn from the viewpoint of suppressing moving image blur.

  Therefore, the timing generation unit 11 according to the first embodiment generates light emission drive signals P1 to Pn that turn on the light sources of the plurality of divided light source regions of the backlight light source unit 15 in accordance with the scanning in the image display unit 17. That is, the timing generation unit 11 performs control to turn on the light source of the divided light source region corresponding to the screen region being switched immediately before the points B1 to Bn at which the first frame is switched to the second frame.

  As a configuration for realizing such an operation, for example, a configuration in which the lighting timing is sequentially shifted by synchronizing the lighting timing of the light source in the divided light source region with the scanning timing (writing timing) is conceivable.

  FIG. 5 shows a time period T of each frame in the image display apparatus 10 according to the first embodiment, a display image of each frame, a temporal change in light transmittance in a plurality of screen regions of the liquid crystal panel which is the image display unit 17, and a plurality of It is a timing chart which shows the light emission drive signal (high level period) P1-Pn of the light source of each divided | segmented light source area | region. The thick lines shown in FIG. 5 are the light emission drive signals P1 to Pn. The light emission drive signals P1 to Pn shown in FIG. 5 are signals using the vicinity of the points B1 to Bn as the reference of the falling edge. The timing generation unit 11 sequentially shifts the lighting timing of the light sources in the plurality of divided light source regions of the backlight light source unit 15 by generating such light emission drive signals P1 to Pn. Here, the light emission drive signals P <b> 1 to Pn are represented by binary signals, the low (L) level is extinguishing the light sources of the plurality of divided light source regions of the backlight light source unit 15, and the high (H) level is the backlight light source unit 15. Represents lighting of each light source in the plurality of divided light source regions. As will be described later, the amount of shift in the lighting timing of the light emission drive signals P1 to Pn is determined by the frame period T of the input image signal I1 and the number n of the divided light source regions in the vertical direction of the backlight light source unit 15.

  FIG. 6 is a timing chart showing the timing relationship between the input image signal I1, the liquid crystal response of the image display unit 17, the light emission drive signals P1 to Pn, and the vertical synchronization signal V included in the input image signal I1. The vertical synchronization signal V is a signal indicating the start timing of the frame and is synchronized with the input image signal I1. In the example of FIG. 6, the period of one frame is T. In FIG. 6, the dotted line represents the liquid crystal response, and the thick solid line represents the light emission drive signals P <b> 1 to Pn input to the backlight light source unit 15. FIG. 6 shows an example in which the number of divided light source regions of the backlight light source unit 15 is four.

In the example illustrated in FIG. 6, the timing generation unit 11 controls the falling edge of the light emission drive signal P1 corresponding to the divided light source region at the top of the screen to be near the point B1. Then, the timing generation unit 11 represents the falling edge of the light emission drive signal P2 corresponding to the divided light source region adjacent to the divided light source region at the top of the screen from the falling edge of the light emission drive signal P1 by the following equation (1). Control is performed so as to be in the vicinity of the point B2, which is a time point delayed by the shift amount S of the time.
S = T / n (1)

  That is, the timing generation unit 11 generates the first falling edge of the light emission drive signal P1 after time T from the rising edge of the vertical synchronization signal V, and shifts the time by the shift amount S shown in the above equation (1). Thus, the fall of the light emission drive signals P2 to Pn is generated. For example, when the number of divided light source regions of the backlight light source unit 15 is 4 as shown in FIG. 6, the falling edge of the light emission drive signal P1 is after the time T has elapsed from the vertical synchronization signal V, and the light emission The falling edge of the drive signal P2 is after T + T / 4 period.

  Since the high level period of the light emission drive signals P1 to Pn becomes the light emission period of the light source in the divided light source region, the timing generation unit 11 does not change the falling timing of the light emission drive signals P1 to Pn when increasing the luminance. Further, the rising timing of the light emission drive signals P1 to Pn is changed to lengthen the high level period of the light emission drive signals P1 to Pn. On the other hand, when darkening the luminance, the timing generation unit 11 does not change the falling timing of the light emission driving signals P1 to Pn, but changes the rising timing of the light emission driving signals P1 to Pn to change the light emission driving signals P1 to Pn. Shorten the high level period. As described above, the timing generation unit 11 performs the luminance adjustment by fixing the falling timing of the light emission drive signals P1 to Pn and adjusting the rising timing. The double-directional arrows shown in FIG. 6 indicate adjustments for increasing and shortening the rising timing.

  Here, consider a case where the number of divided light source regions in the vertical direction of the light source is small. In this case, since the vertical width of one divided light source region of the backlight light source unit 15 is increased, the timing for scanning the liquid crystal in one corresponding screen region is lengthened. As a result, the scanning timing of the liquid crystal is greatly different between the upper part and the lower part even within one screen area.

  In such a case, as shown in FIG. 7, the timing generator 11 assumes a scanning start time at the center position of the vertical width of one screen area, and shifts so that the phases of the light emission drive signals P1 to Pn are uniformly delayed. May be. For example, in the case where the number of divided light source regions n = 4, a quarter of the vertical scanning period of one frame corresponds to the scanning period of one region. For this reason, for example, if the response of the liquid crystal is fast, the target gradation is reached quickly, and the influence of the response start of the next frame is early, so the earlier timing may be better. Therefore, the scanning timing may be balanced by adjusting the phase of the light emission period. That is, in FIG. 6, the light emission drive signal P4 is generated as a scanning start point at the bottom of the screen of the image, but FIG. 7 shows the rise of the vertical synchronization signal V, that is, the top of the screen of the image. It is a figure of the example which shifted the phase of the light emission drive signals P1-P4 uniformly before only the time a from the writing start point. The broken lines indicate the response of the liquid crystal at the lowest point and the start point of division, the point shifted by time a1, respectively. Looking at the overlap of the response of the broken line liquid crystal, it can be seen that the difference between the response of the liquid crystal at the top of the light source split screen and the response of the liquid crystal at the bottom of the light source screen is balanced a little earlier. .

  The response start position by rewriting the next frame has been described so as to be the falling edge of the light emission drive signals P1 to Pn, but the phase is shifted before and after the response start position by rewriting the next frame, and the number of divisions You may fine-tune the response of the liquid crystal. In this way, fine adjustment of scanning timing becomes possible. Thus, the timing generation unit 11 may be configured to adjust the phases of the light emission drive signals P1 to Pn.

  As described above, the timing generation unit 11 controls the timing generation unit 11 to sequentially turn on the light sources of the plurality of divided light source regions of the backlight light source unit 15 in synchronization with scanning of the image signal in the image display unit 17. I do. Thereby, each light source of the several division | segmentation light source area | region of the backlight light source part 15 can be lighted at the appropriate timing corresponding to the response of a liquid crystal. Therefore, the light source of the divided light source region corresponding to the screen region to which the liquid crystal of the image display unit 17 responded sufficiently can be turned on, that is, the backlight light source unit 15 can be turned on when the liquid crystal is in an appropriate state. Therefore, there is an effect that blurring of moving images (motion blurring) in the displayed video can be suppressed.

  On the other hand, light emitters such as lasers and LEDs have the property that the light emission intensity changes according to temperature changes or due to secular changes, and the light emitting element itself has individual differences in the amount of light emission. Alternatively, the color balance may change, and unintended luminance unevenness or color unevenness may occur in the displayed image. In order to cope with such a difference in the light source of the backlight light source unit 15, the light detection unit 13 detects the light intensity of the backlight light source unit 15 and corrects the change in luminance or color by feedback control.

  In order to perform the above-described light detection, the timing generation unit 11 generates a light detection gate signal GA for indicating a predetermined period in which light is detected, and outputs the light detection gate signal GA to the light detection unit 13. That is, the timing generation unit 11 generates a light detection gate signal GA that enables detection of the light detection unit 13 in the predetermined period (hereinafter referred to as “light detection period Ta”), and the light detection gate signal GA is generated. Output to the light detection unit 13. The light detection unit 13 performs light detection only during a light detection period Ta in which the light detection gate signal GA is significant, that is, measures the amount of light from the light guide plate 16 (light from the backlight light source unit 15).

  FIG. 8 shows the input image signal I1, the liquid crystal response of the image display unit 17, and various signals such as the light emission drive signals P1 to Pn and the light detection gate signal GA in the image display device 10 according to the first embodiment. It is a timing chart which shows an example of timing relation. FIG. 8 shows an example in which the divided light source region n = 4.

  In FIG. 8, thin solid lines of the light emission drive signals P1 to Pn indicate lighting timings for sequential lighting, and thick solid lines indicate lighting timings for light detection. A hatched rectangular portion indicates the timing to turn off the light. According to FIG. 8, the lighting timing indicated by the thick solid line and the lighting timing of the hatched rectangular portion among the lighting timings of the light emission drive signals P1 to Pn are shown at the same timing as the light detection gate signal GA. Control is performed so that the light is always turned on during a lighting timing period indicated by a thick solid line, and control is performed so that the light is always turned off during a light-off timing period indicated by a hatched rectangular portion. If the lighting timing period indicated by the thin solid line and the lighting timing period indicated by the thick solid line overlap, the light is turned on as it is, and if the extinguishing timing period indicated by the hatched rectangular part overlaps, the light turns on Even during the timing, turn it off.

  The generation timing of the light emission drive signals P1 to Pn and the light detection gate signal GA will be described. In the first step, the timing generation unit 11 controls the photodetection gate signal GA to be significant only for a photodetection period Ta that is short enough to perform photodetection, and at the same time, The light emission drive signals P1 to Pn in the divided light source region are controlled to be lit only during the light detection period Ta. That is, in the first step, the timing generation unit 11 causes the light sources of all the divided light source regions of the backlight light source unit 15 to be lit during the light detection period Ta during which the light detection unit 13 performs light detection. The light emission drive signals P1 to Pn are generated. As described above, if the lighting timing period indicated by the thin solid line of each light emission drive signal overlaps the lighting timing period indicated by the thick solid line, the lighting timing signal is turned on as it is, and if it is during the extinguishing timing period, Control is performed so that only the light detection period Ta is lit.

  In the second step, the timing generation unit 11 controls the photodetection gate signal GA so as to be significant only for a photodetection period Ta short enough to perform photodetection, and at the same time, the split light source of the backlight source unit 15 The light emission drive signal P1 at the top of the screen, which is the first area, is controlled to be lit for the light detection period Ta, and the divided light source areas other than the first area of the divided light source area are only for the light detection period Ta. Turns off. That is, the timing generation unit 11 has only the light source at the top of the screen, which is the first region of the divided light source region of the backlight light source unit 15, during the light detection period Ta in which the light detection unit 13 performs light detection. The light emission drive signals P1 to Pn are generated so as to light up. As described above, if the lighting timing period indicated by the thin solid line of each light emission drive signal overlaps the lighting timing period indicated by the thick solid line, the light emission driving signal is turned on as it is and is indicated by a hatched rectangular portion. When the turn-off timing overlaps, the light is turned off only during the light detection period Ta. In addition, when there is a lighting timing period indicated by a thick solid line during the light-off timing period, control is performed so that the light detection period Ta is turned on, and when the light-off timing indicated by the hatched rectangular portion overlaps, the light is turned off as it is. To do.

  In the third step, the timing generation unit 11 controls the photodetection gate signal GA so that it is significant only for a photodetection period Ta that is short enough for photodetection, and at the same time, the split light source of the backlight source unit 15 The light emission drive signal P2 of the second area is controlled to be lit for the light detection period Ta, and the divided light source areas other than the second area of the divided light source area are turned off for the light detection period Ta. That is, the timing generation unit 11 emits light so that only the light source in the second region of the divided light source region of the backlight light source unit 15 is lit during the light detection period Ta in which the light detection unit 13 performs light detection. Drive signals P1 to Pn are generated.

  Similarly, in the (n + 1) th step, similarly, the timing generation unit 11 controls the photodetection gate signal GA so that it is significant only for a photodetection period Ta short enough for photodetection. The light emission drive signals P1 to Pn of the nth region of the divided light source region of the light light source unit 15 are controlled to be lit only during the light detection period Ta, and the divided light source regions other than the nth region of the divided light source region are light. It is turned off only during the detection period Ta. That is, the timing generation unit 11 emits light so that only the light source in the nth region of the divided light source region of the backlight light source unit 15 is lit during the light detection period Ta in which the light detection unit 13 performs light detection. Drive signals P1 to Pn are generated.

  In this way, the timing generation unit 11 according to the first embodiment turns on each of the plurality of divided light source regions of the backlight light source unit 15 in accordance with the scanning in the image display unit 17 and performs the light detection period Ta. Light emission drive signals P <b> 1 to Pn that light all the divided light source regions of the backlight light source unit 15 and only the light sources of the respective divided light source regions of the backlight light source unit 15 are generated. In addition, the timing generation unit 11 generates a photodetection gate signal GA that enables detection by the photodetection unit 13 in the photodetection period Ta.

  In the above description, when the backlight light source unit 15 uses light sources of a plurality of colors, not only all the light sources in each divided light source region are turned on, but also the number of colors of the backlight light source unit 15 in each divided light source region. Control may be performed by adding a step so that only one color is lit. That is, the same number of steps as those recorded in the reference value recording unit 12 are performed.

  The light detection timing detection generation interval or step interval may be every frame, every few frames, or every few seconds. What is necessary is just to implement at the space | interval which can fully respond to the time change or temperature change of the light source of the backlight light source part 15. FIG. Further, the order of steps is not limited to the order shown above.

  FIG. 9 shows a period of each frame in the image display device of the comparative example, a temporal change in light transmittance in a plurality of screen areas of the liquid crystal panel, a light emission drive signal (high level period) of light sources in a plurality of divided light source areas, and light. It is a timing chart which shows the detection gate of a detection part. As a configuration different from the case of FIG. 8, a configuration will be described in which light detection of the light sources of each divided light source region is individually performed at the same timing as the lighting timing for sequentially lighting the light sources of the divided light source regions. FIG. 9 is a timing chart showing the timing relationship of the light emission drive signals P1 to Pn generated in this configuration. According to the light emission drive signals P1 to Pn shown in FIG. 9, light detection (illustrated by thick solid lines) of the light sources in the respective divided light source regions is performed in the period within the lighting timing for sequential lighting indicated by thin solid lines. Is called. That is, the light emission drive signals P1 to Pn shown in FIG. 9 do not have a separate light detection period Ta for light detection as shown in FIG. 8, and light detection lighting is performed at the same timing as sequential lighting. Done. In this case, the timing generation unit 11 is configured to control the light detection gate signal GA so as to be significant at the timing when the light of the light sources in the respective divided light source regions is turned on.

  In the timing relationship shown in FIG. 9, not only the light source of one divided light source region is lit but also the light source of the adjacent divided light source region at the timing of detecting the light amount of the light source of one divided light source region. Lights up. For example, in FIG. 9, the light emission drive signal P2 of the adjacent divided light source region is also significant in the light detection period Ta of the divided light source region corresponding to the light emission drive signal P1. As described above, since the light guide plate 16 has an effect of diffusing light over a wide range, the light emitted by the light source in a certain divided light source region is not only the region corresponding to each light guide region of the light guide plate 16, It reaches the area adjacent to it or even further away. Therefore, the amount of light detected in the light detection period Ta includes not only the light source of the divided light source region that is turned on by the light emission drive signal P1, but also the amount of light of the light source of the divided light source region that is turned on by the light emission drive signal P2. There is a problem that the light quantity of the light source in one divided light source region cannot be detected accurately.

  FIG. 10 shows a period of each frame in the image display device of the comparative example, a temporal change in light transmittance in a plurality of screen areas of the liquid crystal panel, a light emission drive signal (high level period) of light sources in a plurality of divided light source areas, and light. It is a timing chart which shows the detection gate of a detection part. When the luminance is changed as described above, for example, when the user controls the luminance to be low, the light emission period for sequential lighting is shortened as shown in FIG. In the case of FIG. 10, the amount of light detected in the light detection period Ta is only the light emitted from the light source in the region corresponding to the light emission drive signal P1, and the influence of the light from the adjacent region is eliminated. However, when the brightness is controlled by the user to be high, not only the divided light source regions to be detected but also the light sources of the adjacent divided light source regions are turned on in the light detection period Ta, so that the configuration shown in FIG. Problem arises.

  As described above, as described in the comparative examples of FIGS. 9 and 10, the light detection of the light sources of each divided light source region is individually performed at the same timing as the lighting timing for sequentially lighting the light sources of the divided light source regions. In this case, there is a problem that the amount of light detected by the light detection unit 13 is not constant depending on the condition of the luminance setting. Further, another configuration in which the lighting timing and the light detection period Ta shown in FIG. 10 are fixed is also conceivable. However, with this configuration, the luminance cannot be further increased.

  On the other hand, in the image display device 10 according to the first embodiment, as illustrated in FIG. 8, the light source of the plurality of divided light source regions of the backlight light source unit 15 at the timing when the light detection unit 13 performs light detection. Control to turn on all and control to turn on only the light sources of one divided light source region among the plurality of divided light source regions. Thereby, the detection of the light intensity for controlling the light emission intensity of each of the light sources in the plurality of divided light source regions of the backlight light source unit 15 can be performed stably and accurately. Further, each of the light sources in the plurality of divided light source regions of the backlight light source unit 15 is turned on according to the scanning in the image display unit 17. Thereby, moving image blur can be suppressed.

  FIG. 11 is a timing chart showing the period of each frame, the light emission drive signal (high level period) of the light sources in the plurality of divided light source regions, and the detection gate of the light detection unit in the image display apparatus 10 according to the first embodiment. . As shown in FIG. 11, even when the user sets the brightness to the maximum, that is, when the backlight light source unit is turned on 100%, a plurality of divided light source regions are used as in the first embodiment. By controlling to turn on only one of the divided light source regions, it is possible to stably and accurately detect the light intensity for controlling the light emission intensity of each of the plurality of divided light source regions of the backlight light source unit 15. it can.

<1-3> Effects of the first embodiment.
As described above, according to the image display device 10 according to the first embodiment, all of the light sources in the plurality of divided light source regions of the backlight light source unit 15 are turned on at the timing when the light detection unit 13 performs light detection. By performing the control, the light detection value D detected is input to the light source control unit 14 and compared with the reference light detection value MDa in a state where all the light sources in the plurality of divided light source regions of the backlight light source unit 15 are turned on. By controlling to determine the light emission intensity value E, it is possible to suppress a change in luminance or color displayed on the image display unit 17.

  Further, the light source control unit 14 detects the light source by controlling to turn on only the light source of one divided light source region among the plurality of divided light source regions of the backlight light source unit 15 at the timing when the light detection unit 13 performs light detection. The detected light detection value D is input, and the light emission intensity value when only the light source of one divided light source area of the plurality of divided light source areas of the backlight light source unit 15 is turned on is compared with the reference light emission intensity value MEn. By controlling so as to determine the light emission intensity value En, it is possible to suppress a change in luminance or color displayed in each divided light source region of the image display unit 17, and partial luminance unevenness of the image display unit 17 or Color unevenness can be suppressed.

  When the control is performed as shown in FIG. 8, a light emission period for light detection occurs in a period other than the timing at which the light sources of the plurality of divided light source regions are sequentially turned on. Therefore, the light emission period (light detection period Ta) for light detection is a short period in which the light detection unit 13 (light sensor) can detect significant light and does not affect the display quality of the image. In other words, it is desirable that the period be momentary that the user cannot perceive.

  Further, according to the first embodiment, the light guide plate 16 has a function of diffusing incident light so that light unevenness does not occur over a wide range, and all the light sources in the plurality of divided light source regions are turned on simultaneously. Since the amount of light is detected during the period, the amount of light can be stably detected regardless of the location of the light detection unit 13 between the image display unit 17 and the light guide plate 16. Therefore, an effect of increasing the degree of freedom in arrangement can be obtained.

  Further, in the first embodiment, even when only one optical sensor is configured, the luminance or emission color of the backlight light source unit is detected in order to detect the amount of light during the period when all the light sources in the plurality of divided light source regions are turned on simultaneously. Since the amount of light is detected during a period in which only one divided light source region of the plurality of divided light source regions is turned on, luminance unevenness or color unevenness can be suppressed.

  In addition, when a plurality of optical sensors of the light detection unit 13 are installed, detection accuracy in light detection can be improved, and unevenness in brightness or color can be further suppressed.

<1-4> Modified example of the first embodiment.
In the above description, the light emission drive signals P1 to P1 that can be controlled to turn on the light sources of the plurality of divided light source regions all at once and control to turn on only the light sources of one divided light source region of the plurality of divided light source regions Pn and the control of the light detection gate signal GA that can be controlled to detect light during that period, and the method of adjusting the brightness and color have been described. It may be performed every frame. Alternatively, the adjustment may be performed every few frames, or every few seconds or minutes. That is, the light source operation of the backlight light source unit 15 and the light detection operation of the light detection unit 13 in the light detection period Ta are performed at intervals that can sufficiently cope with the time change or temperature change of the light source of the backlight light source unit 15. It may be performed every predetermined cycle longer than one frame of the image signal. Thus, if it does not perform lighting and detection for every frame, but carries out at intervals, it is possible to reduce the amount of processing for light detection and adjustment of luminance and color.

<2> Embodiment 2.
<2-1> Configuration of the second embodiment.
FIG. 12 is a block diagram schematically showing the configuration of the image display apparatus 20 according to Embodiment 2 of the present invention. 12, components that are the same as or correspond to the components shown in FIG. 1 are given the same reference numerals as those shown in FIG. The image display device 20 is, for example, a liquid crystal display device, and is provided on the back side of the image display unit 17 such as a transmissive liquid crystal panel, and a backlight light source that emits light toward the back side of the image display unit. Device 20a. The image display device 20 according to the second embodiment is different from the image display device according to the first embodiment in the operation of the timing generation unit 21. In the first embodiment, the timing generation unit 11 generates the light emission drive signals P1 to Pn and the light detection gate signal GA based on the vertical synchronization signal V included in the input image signal I1. On the other hand, in the second embodiment, the timing generation unit 21 generates the light emission drive signals P1 to Pn and the light detection gate signal GA based on the image valid signal DE included in the input image signal I1. In the image display device 20 according to the second embodiment, the configuration and operation other than the timing generation unit 21 are the same as those in the first embodiment.

  The image valid signal DE is a signal indicating a period during which actual image data is transmitted in one frame period of the image. The gradation of the image is written in the liquid crystal of the image display unit 17 during a period (image effective period) Tde in which the image effective signal DE is significant. One frame period T of the image is equal to the sum of the image effective period Tde and the blanking period b1. The blanking period is a period in which no image is written. For example, in the case of a standard high-definition signal, the vertical 1080 lines are the image effective period, but the total number of lines in the vertical period is 1125 lines. The 45 lines of this difference is the blanking period.

<2-2> Operation of the second embodiment.
Next, a detailed operation of the image display device 20 according to the second embodiment will be described with reference to FIG. FIG. 13 shows the input image signal I1, the response of the liquid crystal of the image display unit 17, and the vertical synchronization signal V and the image valid signal DE included in the input image signal I1 in the image display device 20 according to the second embodiment. It is a timing chart which shows the timing relationship with various signals. In the example of FIG. 13, a period in which the image valid signal DE is at a high level is a significant period, that is, an image valid period in which the image data is valid. Is shown.

In FIG. 13, the dotted line indicates the response of the liquid crystal, and the thick solid line indicates the light emission drive signals P <b> 1 to Pn for turning on the backlight light source unit 15. FIG. 13 shows an example in which the number n of the divided light source regions in the vertical direction of the backlight light source unit 15 is 4 (n = 4). The shift amount S of the light emission drive signals P1 to Pn is expressed by the image effective period Tde of the image effective signal DE and the number n of the divided light source regions in the vertical direction of the backlight light source unit 15 as shown in the following equation (2). Determined.
S = Tde / n (2)

  As illustrated in FIG. 13, the timing generation unit 21 shifts the falling timing by the shift amount S by time with respect to the timing for sequentially lighting the light sources in the divided light source regions of the light emission drive signals P1 to Pn. Specifically, the falling timings of the light emission drive signals P1 to Pn are time-shifted by the shift amount S with reference to the rising edge of the image valid signal DE. Since the high level period of the light emission drive signals P1 to Pn is the light emission period of the light source in the divided light source region, the timing generation unit 21 changes the rise timing without changing the fall timing when increasing the luminance. , Make the high level period longer. On the other hand, when darkening the luminance, the timing generation unit 21 changes the rising timing without changing the falling timing to shorten the high level period. Thus, the timing generation unit 21 adjusts the luminance by fixing the falling timing of the light emission drive signals P1 to Pn and adjusting the rising timing. A double-headed arrow shown in FIG. 13 indicates an adjustment for increasing and shortening the rising timing.

<2-3> Effects of the second embodiment.
As described above, according to the image display device 20 according to the second embodiment, since the timing control of the light emission drive signals P1 to Pn is performed based on the image valid signal DE, it is strictly synchronized with the image writing scan. The light sources in the plurality of divided light source regions of the backlight light source unit 15 can be sequentially turned on at a timing that can be taken. Therefore, according to the image display device 20 according to the second embodiment, the light source of the divided light source region corresponding to the screen region to which the liquid crystal of the image display unit 17 responded sufficiently is turned on, that is, the liquid crystal is in an appropriate state. Since the backlight light source unit 15 can be turned on in some cases, there is an effect that the moving image blur of the displayed video can be suppressed.

<3> Third Embodiment
<3-1> Configuration of the third embodiment.
FIG. 14 is a block diagram schematically showing the configuration of the image display device 30 according to the third embodiment of the present invention. 14, components that are the same as or correspond to those shown in FIG. 1 are given the same reference numerals as those shown in FIG. The image display device 30 is, for example, a liquid crystal display device, and is provided on the image display unit 17 such as a transmissive liquid crystal panel and on the back side thereof, and a backlight light source that emits light toward the back surface of the image display unit. Device 30a. The image display device 30 according to the third embodiment is different from the image display device 10 according to the first embodiment in that it includes an image signal analysis unit 32 and the operation of the timing generation unit 31. In the image display device 30 according to the third embodiment, the configuration and operation other than the image signal analysis unit 32 and the timing generation unit 31 are the same as those in the first embodiment.

  In the image display device 30 according to Embodiment 3, the input image signal I1 is input to the image signal analysis unit 32 and the image display unit 17. The image reference signal B0 included in the input image signal I1 is input to the timing generation unit 31. That is, except that the input image signal I1 is input to the image signal analysis unit 32, the input of the input image signal I1 and the image reference signal B0 in the third embodiment is the same as in the first embodiment.

  The image signal analysis unit 32 relates to the luminance (in this case, luminance information) of the input image signal I1 with respect to each of the plurality of divided light source regions 1511 to 151m and 1521 to 152m (for example, 1511 to 1514 and 1521 to 1524) of the backlight light source unit 35. ), Image analysis information Y11 to Y14 and Y21 to Y24 indicating the analysis results are generated and output to the timing generation unit 31. That is, the image analysis information Y11 to Y14, Y21 to Y24 includes the same number of signals Y11 to Y14 and Y21 to Y24 as the number of divided light source regions.

  The timing generation unit 31 basically has the same function as the timing generation unit 11 described in the first embodiment. The timing generation unit 31 generates a light detection gate signal GA that causes the light detection unit 13 to detect the light intensity of the backlight light source unit 35 based on the image reference signal B0, and uses the light detection gate signal GA as the light detection unit 13. Output to. The timing generation unit 31 generates light emission drive signals P11 to P14 and P21 to P24 for turning on and off the backlight light source unit 35 based on the image reference signal B0, and the generated light emission drive signals P11 to P14, P21 to P24 are output to the backlight light source unit 35. The light emission drive signals P <b> 11 to P <b> 14 and P <b> 21 to P <b> 24 include the same number of signals as the number of divided light source regions of the backlight light source unit 35.

  15A and 15B are a front view and a side view schematically showing the arrangement of the backlight light source unit 35, the light guide plate 16, and the light detection unit 13 of the image display device 30 according to the third embodiment. is there. In the example shown in FIGS. 15A and 15B, a light guide plate 16 that is a kind of light guide unit is disposed on the back of the image display unit 17, and the left side of the light guide plate 16 (the left end and the right end of the image display unit 17). ) Is provided with a backlight source 35. The backlight light source unit 35 is disposed at the left and right ends in FIGS. 15A and 15B, but may be disposed directly below the light guide plate 16. Here, the light detection unit 13 is arranged at the center of the light guide plate in plan view. However, as long as it is arranged between the light guide plate 16 and the image display unit 17 in the same manner as described above, the light detection unit 13 is arranged at an arbitrary place. Good.

  In FIGS. 15A and 15B, the backlight source 35 is independently controlled in each of n (= 2 × m) divided light source regions, which are two in the horizontal direction and m in the vertical direction. Light sources that can be used (in FIG. 15A and FIG. 15B, three color light sources of red (R), green (G), and blue (B)) are arranged. The light emitted from the backlight light source unit 35 is diffused by the light guide plate 16 and guided from end to end in the liquid crystal panel in plan view. During this time, light from the light sources of three colors of red (R), green (G), and blue (B) is mixed to become white light. Then, the diffused light is detected by the light detection unit 13. In FIGS. 15A and 15B, Er_11, Eg_11, and Eb_11 mean the emission intensity values E of the three color light sources of red, green, and blue in the upper left divided light source region in FIG. , Dr, Dg, and Db mean light detection values D of light of three colors of red, green, and blue.

  Since the light guide plate 16 has a function of diffusing incident light so that light unevenness does not occur over a wide range, light emitted from the light source in one divided light source region of the backlight light source unit 35 is transmitted through the light guide plate 16. Rather than illuminating only one corresponding light guide region (a range indicated by a dotted line on the light guide plate 16 in FIG. 15A), adjacent light guide regions in the light guide plate 16 or further apart from each other Also shine a little. In other words, one light guide region of the light guide plate 16 is not only the light emitted from the light source of one corresponding divided light source region of the backlight light source unit 35, but also the light source of the divided light source region adjacent thereto, or A certain amount of light emitted from the light sources in the separated light source regions is emitted with a total light amount.

<3-2> Operation of the third embodiment.
Next, the operation of the image display device 30 according to Embodiment 3 will be described in detail. First, the operation of the image signal analysis unit 32 will be described in detail with an example of a specific operation. First, the image signal analysis unit 32 calculates the average luminance HYa of the entire screen of the input image signal I1. Next, the image signal analysis unit 32 calculates average luminances HY1, HY2 to HYn for each screen area of the input image corresponding to the divided light source area. For example, when the screen area is divided into two horizontal parts and four vertical parts as shown in FIG. 15A, the image signal analyzing unit 32 has eight screens of horizontal 1/2 and vertical 1/4. An average luminance is calculated for each of the areas. Then, the image signal analysis unit 32 generates image analysis information Yn based on the overall average brightness HYa and the average brightness HYn for each screen area. The image analysis information Yn is, for example, a comparison result between the overall average brightness HYa and the average brightness HYn for each screen area, or a difference as shown in the following equation (3).
Yn = g × (Hyn−Hya) (3)

  Here, g is gain information for determining the influence of the difference in average luminance on the image analysis information Yn. The unit of the image analysis information Yn may be expressed, for example, as a percentage where the minimum average luminance value is 0% and the maximum average luminance value is 100%, or a multi-bit gradation value (0 to 8 for 8 bits). (Value in the range of 255). Further, the image analysis information Yn may be assigned to a certain normalized luminance level.

  FIGS. 16A and 16B will be described in more detail with reference to specific examples of the input image signal I1. In the examples of FIGS. 16A and 16B, the backlight light source unit 35 is divided into two horizontal parts and four vertical parts. In FIGS. 16A and 16B, a dotted line indicates a boundary line of the screen area corresponding to the divided light source area. FIG. 16A shows an image having a bright sun and dark clouds in the sky as an example of the image indicated by the input image signal I1.

  FIG. 16B shows an example of image analysis information Yn generated by the image signal analysis unit 32 for the input image signal I1 indicating the image of FIG. Here, the average luminance of the image for each screen area (each divided light source area of the backlight light source unit 35) is shown in five levels for simplicity. In the example of FIG. 16B, the luminance level L1 has the lowest average luminance level, and the luminance level L5 has the highest average luminance level. In the example of FIG. 16B, the average luminance HYa of the entire screen is the luminance level L3.

  For example, the image signal analysis unit 32 generates the image analysis information Y11 = 0 for the screen area (divided light source area) because the average brightness of the screen area at the top of the left screen is the same as the overall average brightness. In addition, for example, the image signal analysis unit 32 performs image analysis on the screen area (divided light source area) because the average brightness of the second screen area from the upper right side where the sun is displayed is higher than the overall average brightness. Information Y22 = + 2 is generated. For example, the image signal analysis unit 32 performs image analysis on the screen area (divided light source area) because the average brightness of the screen area at the bottom of the left screen where dark clouds are displayed is smaller than the overall average brightness. Information Y14 = -2 is generated.

  The image signal analyzer 32 configured in this manner compares the average luminance of the screen area with the overall average luminance and outputs the result as image analysis information Yn. Then, the image signal analysis unit 32 generates image analysis information Yn having a large value for the divided light source region corresponding to the screen region having a higher average luminance than the overall average luminance, and the average luminance is higher than the overall average luminance. For the divided light source region corresponding to the low screen region, image analysis information Yn having a small value is generated. In the above example, the image analysis information Yn is obtained using the luminance information of the image. For example, the highest gradation among the red (R), green (G), and blue (B) of the image signal is obtained. The image analysis information Yn may be obtained by replacing the average value of the signals.

  Next, the operation of the timing generation unit 31 will be described in detail. FIG. 17 shows the input image signal I1, the response of the liquid crystal of the image display unit 17, and the light emission drive signal P11 when the input image signal I1 indicating the image as shown in FIGS. 15A and 15B is input. It is a timing chart which shows an example of timing relationship with various signals, such as -P14, P21-P24, and photodetection gate signal GA. The vertical synchronization signal V is a signal indicating the start timing of the frame and is synchronized with the input image signal I1. In the example of FIG. 17, the period of one frame is T. In FIG. 17, as in FIG. 6, the thick solid lines are the light emission drive signals P <b> 11 to P <b> 14 and P <b> 21 to P <b> 24 input to the backlight light source unit 35, and the number of divided light source regions of the backlight light source unit 35 is eight. An example of a case where the backlight light source unit 35 is divided into two parts in the horizontal direction and four parts in the vertical direction is shown.

  Similar to the timing generation unit 11 described in the first embodiment, the timing generation unit 31 outputs the light emission drive signals P11 to P14 and P21 to P24 immediately before the start of writing the image data of the next frame on the liquid crystal panel. By controlling to fall (the lighting period ends), the backlight source 35 can emit light at an appropriate timing in consideration of the response of the liquid crystal.

  Specifically, in the divided light source regions at the same position in the vertical direction (divided light source regions adjacent in the horizontal direction), the writing of image data to the liquid crystal panel occurs at almost the same timing. The light emission drive signals P11 to P14 and P21 to P24 corresponding to the divided light source regions are controlled to fall at the same timing.

  For example, the timing generation unit 31 performs control so that the light emission drive signals P11 and P21 of the divided light source region corresponding to the screen region at the top of the screen fall simultaneously. Further, for example, the light emission drive signals P21 and P22 of the divided light source regions that are adjacent to the divided light source regions in the vertical direction are shifted from the light emission drive signals P11 and P21 by the time shift amount S represented by the above equation (1). Control to fall at the delayed time.

  That is, the timing generation unit 31 generates the first falling edge of the light emission drive signals P11 and P21 after the time T from the rise of the vertical synchronization signal V, and shifts the time by the shift amount S shown in the above equation (1). As a result, falling edges of the light emission drive signals P21 and P22, P31 and P32,..., Pm1 and Pm2 (m is a positive integer) are generated. For example, as shown in FIG. 17, when the number of the divided light source regions in the vertical direction of the backlight light source unit 35 is 4, the falling edges of the light emission drive signals P11 and P21 have elapsed time T from the vertical synchronization signal V. Later, the falling edges of the light emission drive signals P21 and P22 are after the elapse of the T + T / 4 period.

  Since the high-level period of the light emission drive signals P11 to P14 and P21 to P24 is the light emission period of the light source in the divided light source region, the timing generation unit 31 does not change the fall timing when increasing the brightness, but rises timing. To increase the high level period. On the other hand, when darkening the luminance, the timing generation unit 11 changes the rising timing without changing the falling timing to shorten the high level period. As described above, the timing generation unit 31 performs the brightness adjustment by fixing the falling timing of the light emission drive signals P11 to P14 and P21 to P24 and adjusting the rising timing.

  Here, the timing generation unit 31 changes the high-level period of the light emission drive signals P11 to P14 and P21 to P24 based on the image analysis information Yn output from the image signal analysis unit 32. That is, the timing generation unit 31 includes a plurality of divided light source regions 1511 to 151m and 1521 to 152m of the backlight light source unit 35 according to scanning in the image display unit 17 based on the image analysis information Y11 to Y14 and Y21 to Y24. Each high level period (lighting period) is controlled.

  Here, the image analysis information Y11 to Y14 and Y21 to Y24 are generated based on the average luminance of the entire screen and the average luminance of each screen area as described above. Therefore, the timing generation unit 31 uses the high-level periods of the light emission drive signals P11 to P14 and P21 to P24 corresponding to the luminance setting values of the entire screen that can be set by the user as a reference, and the image analysis information Y11 to Y14, Y21 to Y24. Based on this, the high level periods of the light emission drive signals P11 to P14 and P21 to P24 are increased or decreased.

  Specifically, when the values of the image analysis information Y11 to Y14 and Y21 to Y24 of the screen area are larger than the average luminance value of the entire screen, the timing generation unit 31 emits the light emission drive signal P11 of the corresponding divided light source area. The high level periods of P14 and P21 to P24 are made longer than the reference high level period to control the brightness in the screen area to be brighter. Conversely, when the values of the image analysis information Y11 to Y14 and Y21 to Y24 of the screen area are smaller than the average luminance value of the entire screen, the timing generation unit 31 emits the light emission drive signals P11 to P14 of the corresponding divided light source area. , P21 to P24 are controlled so as to make the luminance in the screen area darker by making the high level period shorter than the reference high level period.

  FIG. 17 shows how the high-level periods of the light emission drive signals P11 to P14 and P21 to P24 in the corresponding divided light source regions are changed by the image analysis information Y11 to Y14 and Y21 to Y24, respectively. In the screen area at the top of the left screen shown in FIG. 15A, since the image analysis information Y11 = 0, the timing generation unit 31 sets the light emission drive signal P11 of the corresponding divided light source area to the reference high level. Control to be high level only for the period. In the uppermost screen area on the right side shown in FIG. 15A, since the image analysis information Y21 = + 1, the timing generation unit 31 sets the light emission drive signal P21 of the corresponding divided light source area to the reference high level. Control is performed so as to be high level for a period slightly longer than the period. In the screen area at the bottom of the right screen shown in FIG. 15A, since the image analysis information Y24 = −2, the timing generation unit 31 uses the light emission drive signal P24 of the corresponding divided light source area as a reference. The high level is controlled for a period shorter than the high level period.

<3-3> Effects of the third embodiment.
As described above, according to the image display device 30 according to the third embodiment, if the average luminance HYn of the screen region is larger than the overall average luminance HYa, the luminance of the corresponding divided light source region can be increased. If the average brightness HYn of the screen area is smaller than the overall average brightness HYa, the brightness of the corresponding divided light source area can be lowered. Therefore, according to the image display device 30 according to the third embodiment, since the luminance of the divided light source region of the backlight light source unit 35 can be changed according to the luminance of each screen region of the input image signal I1, display The contrast of the image can be increased.

  In addition to the above operation, the timing generation unit 31 according to the third embodiment also performs the same operation as the timing generation unit 11 according to the first embodiment. For example, the timing generation unit 31 lights all the light sources of the plurality of divided light source regions of the backlight light source unit 35 according to the scanning in the image display unit 17, and all of the backlight light source units 35 in the light detection period Ta. The control for turning on the light sources in the divided light source regions and the control for turning on only the light sources in one of the divided light source regions and turning off the light sources in the other divided light source regions are performed. Then, the timing generation unit 31 generates a light detection gate signal GA that enables the detection of the light detection unit 13 in the light detection period Ta. Therefore, according to the image display device 30 according to the third embodiment, as in the first embodiment, detection of light intensity for controlling the light emission intensity of each of the plurality of divided light source regions of the backlight light source unit 35 is performed. This can be performed stably and accurately, and blurring of moving images can be suppressed.

<4> Modifications.
Although the embodiments of the present invention have been described above, the present invention can be combined with the configurations of the embodiments within the scope of the invention, and the configurations of the embodiments can be appropriately modified or omitted. Is possible.

  10, 20, 30 Image display device, 10a, 20a, 30a Backlight light source device, 11, 21, 31 Timing generation unit, 12 Reference value recording unit, 13 Light detection unit, 14 Light source control unit, 15, 35 Back light source Part, 16 light guide plate, 17 image display part, 32 image signal analysis part.

Claims (6)

An image display unit having a screen and a screen driving unit that sequentially scans the screen in a predetermined direction in synchronization with the input image signal and changes the light transmittance of the screen according to the input image signal;
A backlight light source unit that has a plurality of divided light source regions and emits light from the plurality of divided light source regions toward the screen;
A light detection unit that detects the intensity of light emitted from the backlight light source unit and outputs a light detection value indicating the intensity of the light;
A light source control unit that controls light emission intensity of each of the plurality of divided light source regions based on the light detection value output from the light detection unit;
Timing generation for generating a light emission drive signal for causing the backlight light source unit to emit light and a light detection gate signal for enabling detection of the light intensity by the light detection unit based on a reference signal included in the input image signal The department and
The light emission drive signal generated by the timing generation unit is:
While sequentially turning on the light sources of the plurality of divided light source regions of the backlight light source unit according to the scanning in the image display unit,
In the detection period in which the light detection gate signal enables detection of the light detection unit, all of the light sources in the plurality of divided light source regions of the backlight light source unit are turned on, and the light detection gate signal is the light detection unit. In a plurality of other detection periods that enable detection of the light source, the light source of the one divided light source region selected from the plurality of divided light source regions of the backlight light source unit is turned on, and the other divided light source regions An image display device characterized in that the light source is turned off. A light guide unit that converts light emitted from the backlight light source unit into light directed to the screen of the image display unit;
The image display device according to claim 1, wherein the light detection unit is installed between the image display unit and the light guide unit. Analyzing the luminance of the image signal for each of the divided light source regions, further comprising an image signal analysis unit for generating image analysis information indicating the analysis result,
The timing generation unit controls a lighting period of each of the plurality of divided light source regions of the backlight light source unit according to the scanning based on the image analysis information. The image display device described.   4. The image display device according to claim 1, wherein the image reference signal included in the image signal includes a vertical synchronization signal or an image valid signal. 5.   The light detection gate signal turns on and off the light sources of the plurality of divided light source regions of the backlight light source unit in the detection period in which the detection of the light detection unit is enabled, and the detection of the light detection unit 5. The image display device according to claim 1, wherein the image display device is performed in a cycle of one frame period or more of an input image signal. The light detection gate signal turns on and off the light sources in the plurality of divided light source regions of the backlight light source unit in the detection period in which the detection of the light detection unit is validated according to the scanning in the image display unit. 6. The image display device according to claim 1, wherein the image display device is executed in preference to sequential lighting of the light sources of the plurality of divided light source regions of the backlight light source unit to be performed.

Images