JP2019102184A - Image display device and control method thereof - Google Patents

Abstract

To provide an image display device capable of achieving image display of a wide luminance dynamic range and capable of suppressing a change in luminescent colors from a light emission section, and to provide a control method of the image display device.SOLUTION: An image display device includes a display section 120 for displaying an image based on image data and a light emission section 130 for irradiating the display section 120 with light from the rear side. A light emission amount control section 150, when light emission luminance of the light emission section 130 is a low luminance range and a high luminance range, performs current amount control for controlling a current amount of a driving current of the light emission section 130. When the light emission luminance of the light emission section 130 is an intermediate luminance range between the low luminance range and the high luminance range, the light emission amount control section 150 does not execute current amount control and executes pulse width control for controlling pulse width of a driving current of the light emission section.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image display apparatus including a light emitting unit and a control method thereof.

  In recent years, in the EOTF (Electro Optical Transfer Function) processing of an image display apparatus, a wide luminance dynamic range is defined by the international standard SMPTE-ST 2084 or the like. In an image display apparatus using a liquid crystal panel, in order to express an image display in such a wide luminance dynamic range, in addition to the transmittance control of the liquid crystal panel, the light emission amount control of the backlight (light emitting portion) is performed. The luminance dynamic range of the display image is expanded. Therefore, it is necessary to control the light emission amount of the backlight in a wide luminance range.

  Patent Document 1 below discloses that the amount of light emission of the backlight is controlled by combining both the amount of driving current of the backlight and the pulse width. Specifically, the pulse width is controlled by keeping the amount of current constant in the low luminance region, and the pulse width becomes 100% duty in the high luminance region, so that the amount of driving current is controlled.

  Further, the technology described in Patent Document 2 below discloses a technology for correcting a video signal in accordance with the amount of drive current so that the color of a display image does not change when the amount of drive current for backlight is changed. .

Japanese Patent Application Laid-Open No. 2002-56996 JP, 2011-85693, A

  If the amount of light emitted from the backlight is controlled by changing the amount of driving current, the color of light from the backlight will change. In particular, when the luminance dynamic range is wide, color visibility of the color is high in the intermediate luminance range excluding the dark low luminance range and the very bright high luminance range, and the color change of the display image due to the color change of the backlight Easy to see. Even if the technology described in Patent Document 1 is used, the amount of driving current of the backlight is controlled in the intermediate luminance range, so that the color change of the display image caused by the color change of the backlight is visually recognized.

  In particular, in a backlight using an LED (Light Emitting Diode) as a light source, the spectral characteristics are likely to change if the amount of driving current of the LED is changed. High-precision color display is important in professional displays such as master monitors. Therefore, as described in Patent Document 2, it is difficult to correct the video signal with high accuracy according to the amount of drive current, and it is mounted on a business display such as a master monitor where faithful color reproduction of the input image is required. Is difficult. In a factory or the like, much work is also required to adjust video signals.

  Therefore, the present invention has been made in view of the above-mentioned problems, and realizes an image display of a wide luminance dynamic range, and an image display device capable of suppressing a change in color of light emitted from a light emitting unit It aims at providing the control method.

  In order to solve the problems described above, an image display apparatus according to an embodiment of the present invention includes a display unit that displays an image based on image data, and a light emitting unit that emits light to the display unit from the back side. When the light emission luminance of the light emitting unit is in the low luminance range and in the high luminance range, current amount control is performed to control the current amount of the drive current of the light emitting unit, and the light emission luminance of the light emitting unit is high and low A control unit that controls the light emission amount of the light emitting unit by performing the pulse width control that controls the pulse width of the drive current of the light emitting unit without performing the current amount control when it is an intermediate luminance range between the luminance ranges And.

  In addition, a control method of an image display device according to an embodiment of the present invention includes an image display unit that displays an image based on image data, and a light emission unit that emits light to the display unit from the back side. In the control method of a display device, when the light emission luminance of the light emitting unit is in the low luminance range and in the high luminance range, current amount control is performed to control the current amount of the drive current of the light emitting unit. When the light emission luminance is in the low luminance range, the control step of controlling the light emission amount of the light emitting unit by performing the pulse width control of controlling the pulse width of the drive current of the light emitting unit without performing the current amount control It is characterized by

  According to the present invention, it is possible to realize image display with a wide luminance dynamic range and to suppress a change in emission color from the light emitting unit.

FIG. 1 is a block diagram showing a configuration of an image display device according to Embodiment 1. It is a flowchart for demonstrating the operation | movement of the image display apparatus shown in FIG. FIG. 5 is a diagram showing an example of image data input in the first embodiment. FIG. 6 is a diagram showing an example of the correspondence between the image feature amount and the light emission luminance in the first embodiment. It is a figure which shows an example of a control value table. It is a figure which shows the relationship between light-emitting luminance and electric current amount control value. FIG. 7 is a block diagram showing a configuration of an image display device according to Embodiment 2. It is a flowchart for demonstrating the operation | movement of the image display apparatus shown in FIG. FIG. 10 is a diagram showing an example of image data input in the second embodiment. FIG. 18 is a diagram showing an example of the correspondence between the image feature amount and the light emission luminance in the second embodiment.

  Hereinafter, embodiments of the present invention will be described using the drawings. The technical scope of the present invention is determined by the scope of the claims, and is not limited by the embodiments exemplified below. Moreover, not all combinations of features described in the embodiments are essential to the present invention. The contents described in the specification and the drawings are for illustrative purposes only and should not be considered as limiting the present invention. Various modifications (including organic combinations of the respective embodiments) are possible based on the spirit of the present invention, and they are not excluded from the scope of the present invention. That is, the configuration in which each embodiment and its modification are combined is all included in the present invention.

  The image display apparatus shown in each embodiment of the present invention includes a display panel and a backlight for illuminating the display panel from the back. In addition, although a liquid crystal panel is illustrated as a display panel below and an LED light emitting element is illustrated as a light source of a backlight, the light source of a display panel or a backlight is not restricted to this. For example, the light source of the backlight may be an organic EL element or a laser light source. The display panel may be a display panel having an element other than a liquid crystal element (an element capable of controlling the transmittance of light from the backlight). The present invention is also applicable to a liquid crystal projector or the like which projects an image on a screen.

Embodiment 1
FIG. 1 is a block diagram showing the configuration of the image display apparatus according to the first embodiment. The image display device of FIG. 1 includes an image input unit 100, an image processing unit 110, a display unit 120, a light emission unit 130, an operation input unit 140, a light emission amount control unit 150, and a light source drive unit 160.

  The image input unit 100 is an input interface such as, for example, a high-definition multimedia interface (HDMI (registered trademark)), a digital interface (DVI), and a display port. The image input unit 100 includes an input terminal and a receiver unit. The image input unit 100 is connected to an image output device such as a personal computer or a video player. The image input unit 100 receives image data (image signal) from the image output device, and outputs the input image data to the image processing unit 110.

  The image processing unit 110 performs tone correction processing, edge enhancement processing, noise reduction processing, and the like on the image data input from the image input unit 100, and outputs the image data to the display unit 120. In the present embodiment, the image data input from the image input unit 100 is described as moving image data consisting of a plurality of frames, but may be still image data. The image processing unit 110 acquires an image feature amount for each frame of the image data input from the image input unit 100. The image feature amount is, for example, a maximum value (maximum brightness value) or an average value (average brightness value) of pixel values (brightness values) of an image of one frame. The image processing unit 110 determines the light emission luminance of the light emitting unit 130 based on the acquired image feature amount. When the image feature amount is small, the light emission luminance is determined to be low so that the light emission amount of the light emitting unit 130 becomes small in order to display the image dark. When the image feature amount is large, in order to display an image brightly, the light emission luminance is determined to be high so that the light emission amount of the light emitting unit 130 becomes large. The light emission luminance corresponds to, for example, the brightness of the light emitting unit 130, and is the brightness when white image data is displayed on the display unit 120. The image processing unit 110 outputs light emission luminance information indicating the determined light emission luminance to the light emission amount control unit 150.

  The display unit 120 is, for example, a display panel such as a liquid crystal panel. The light emitting unit 130 is disposed on the back side of the display unit 120. When the light emitting unit 130 emits light from the back side of the display unit 120, the user can view the image displayed on the display unit 120. The display unit 120 modulates the light from the light emitting unit 130 by controlling the transmittance of the display panel according to the image data input from the image processing unit 110 to perform image display.

  The light emitting unit 130 is a planar light emitting body in which a large number of LED light sources are disposed, and is a backlight that irradiates the display unit 120 with white light from the back side. The LED light source may be configured by a white LED, or may be configured by a red LED, a blue LED, and a green LED that emit synthetic white light. The light emission amount of the light emitting unit 130 can be adjusted by the drive current value and the pulse width control value (PWM value). When the driving current amount is large, the light emission amount of the light source becomes large, and the light emission luminance becomes high. In addition, when the amount of driving current is small, the light emission amount of the light source becomes small, and the light emission luminance becomes low. In addition, the drive current of the light source of the light emitting unit 130 can be adjusted by pulse width modulation, and when the pulse width is large, the light emission amount of the light source becomes large and the light emission luminance becomes high. In addition, when the pulse width is small, the light emission amount of the light source becomes small, and the light emission luminance becomes low. As described above, by adjusting the light emission amount of the light emitting unit 130 with both the drive current value and the pulse width control value (PWM value), image display with a wide luminance dynamic range is realized.

  The operation input unit 140 is an interface including an operation unit such as a button or a key. However, the operation input unit 140 may be configured to receive an operation signal from the remote control. The user can adjust the light emission amount gain of the light emission unit 130 by adjusting the light emission amount gain of the light emission unit 130 by operating the operation input unit 140. When the light emission amount gain is large, the light emitting unit 130 is brightened, and when the light emission amount gain is small, the light emitting unit 130 is dark. The operation input unit 140 outputs the light emission amount gain designated by the user to the light emission amount control unit 150.

  The light emission amount control unit 150 controls the light emission amount of the light source of the light emitting unit 130. Specifically, a current amount control value for controlling the drive current amount of the light source and a pulse width control value for controlling the pulse width of the light source are determined to control the brightness of the light source. For example, based on the light emission luminance value obtained by multiplying the light emission luminance determined by the image processing unit 110 by the light emission amount gain input from the operation input unit 140, the current amount control value and the pulse width control value Decide. Details of the method of determining the current amount control value and the pulse width control value will be described later. The light emission amount control unit 150 is, for example, a central processing unit (CPU), and controls the operation of the light source drive unit 160 by reading and executing a program from the ROM.

  The light source driving unit 160 is a driver circuit that drives the light source of the light emitting unit 130. The light source drive unit 160 controls the current amount of the drive current of the light emitting unit 130 in accordance with the current amount control value determined by the light emission amount control unit 150. Further, in accordance with the pulse width control value determined by the light emission amount control unit 150, the pulse width of the drive current of the light emitting unit 130 is controlled.

  When the image data input to the image display device is dark as a whole, the amount of light emission of the light emitting unit 130 that illuminates the entire screen becomes small, so the display image is expressed dark. Further, when the image data input to the image display device is entirely bright, the amount of light emission of the light emitting unit 130 illuminating the entire screen is increased, and thus the display image is expressed brightly.

  FIG. 2 is a flow chart for explaining the operation of the image display device shown in FIG. First, in step S11, image data is input from the image output device to the image input unit 100.

  FIG. 3 shows an example of input image data. The images 501, 502, and 503 are all images having uniform signal values over the entire surface. The image 501 is an image (low intensity image) darker than the image 502, and the image 503 is an image brighter than the image 502 (high intensity image).

  In step S12, the image processing unit 110 acquires an image feature amount of the image data input from the image input unit 100. For example, the image feature amount of the image 501 is T1, the image feature amount of the image 502 is T2, and the image feature amount of the image 503 is T3.

  In step S13, the image processing unit 110 determines the light emission luminance of the light emitting unit 130 according to the acquired image feature amount. FIG. 4 is a diagram showing an example of the correspondence between the image feature amount and the light emission luminance. In FIG. 4, the horizontal axis is the image feature amount of the input image data, and the vertical axis is the light emission luminance of the light emitting unit 130. The light emission luminance is determined such that the light emission luminance is larger as the image feature amount is larger and the light emission luminance is smaller as the image feature amount is smaller.

  Then, the light emission amount control unit 150 multiplies the light emission luminance determined by the image processing unit 110 by the light emission amount gain set by the user to determine the final light emission luminance. For example, for the image 501, after the light emission luminance Y1 corresponding to the image feature amount T1 is determined, the light emission luminance Y1 is multiplied by the light emission amount gain, and the light emission luminance L1 after multiplication is determined. For the image 502, after the light emission luminance Y2 corresponding to the image feature amount T2 is determined, the light emission luminance Y2 is multiplied by the light emission amount gain, and the light emission luminance L2 after multiplication is determined. For the image 503, after the light emission luminance Y3 corresponding to the image feature amount T3 is determined, the light emission luminance Y3 is multiplied by the light emission amount gain, and the light emission luminance L3 after multiplication is determined.

  In step S14, the light emission amount control unit 150 determines the current amount control value and the pulse width control value of the light emitting unit 130 from the final light emission luminance determined in step S13.

  FIG. 5 is a diagram showing an example of a control value table showing the relationship between the light emission luminance and the current amount control value and the pulse width control value used in the process of determining the current amount control value and the pulse width control value by the light emission amount control unit 150. It is. When the light emitting unit 130 is driven with the current amount control value and the pulse width control value shown in FIG. 5, for example, the brightness of the white image data becomes equal to the light emission luminance value. In the control value table of FIG. 5, the current amount control value is constant in the middle luminance range where the color visibility is relatively high, and the light emission luminance is changed by the pulse width control value. Further, in a low luminance range and a high luminance range in which color visibility is relatively low, the light emission luminance is changed by the current amount control value and the pulse width control value.

FIG. 6 is a diagram showing the relationship between the light emission luminance and the current amount control value in the control value table shown in FIG. In FIG. 6, the horizontal axis is the light emission luminance, and the vertical axis is the current amount control value. The current amount control value is constant in the middle luminance range between the low luminance range and the high luminance range. Generally, in a low luminance range of less than 3.4 [cd / m ² ], since full photopic vision is not used, the visual sensitivity to the color is low and the visibility of the color is low. In addition, it is difficult to look at an image because it looks dazzling in a high luminance range of 400 [cd / m ² ] or more, and the visibility of the color is low. On the other hand, in the middle luminance range between the low luminance range and the high luminance range, a change in color is easily visible. In the present embodiment, and the constant current control value in a range of to include as possible intermediate luminance range of ^{10 [cd / m 2] 399} [cd / m 2]. In the low luminance range of less than 10 cd / m ² and the high luminance range of 400 cd / m ² or more, the current amount control value is changed according to the light emission luminance. As described above, in the low luminance range and the high luminance range, an image display with a wide luminance dynamic range is realized by adjusting the light emission amount of the light emitting unit 130 with both the drive current value and the pulse width control value (PWM value). Be done.

For example, when the light emission luminance L1 of the image 501 is 10 cd / m ² , the current amount control value is 20 and the pulse width control value is 150 according to the control value table of FIG. When the light emission luminance L2 of the image 502 is 399 [cd / m ² ], the current amount control value is 20 and the pulse width control value is 3000 according to the control value table of FIG. When the light emission luminance L3 of the image 503 is 1000 cd / m ² , the current amount control value is 50 and the pulse width control value is 3000 according to the control value table of FIG.

  Next, in step S15, the light emission amount of the light emitting unit 130 is controlled using the current amount control value and the pulse width control value determined in step S14.

  For example, when displaying the image 501, the light emitting unit 130 is driven based on the current amount control value 20 and the pulse width control value 150. When the image 502 is input, the light emitting unit 130 is driven based on the current amount control value 20 and the pulse width control value 3000. That is, when displaying the image 501 and displaying the image 502, the light emitting unit 130 is controlled with the same current amount control value 20 (controlled with the same amount of drive current). In the case where the light emitting unit 130 is a backlight of an LED light source, when the amount of driving current is changed, the spectral characteristics change, and thus the color of light emitted tends to change. However, when the image 501 is displayed and when the image 502 is displayed, since the amount of drive current is the same, a change in spectral characteristics of the light emitting unit 130 is suppressed, and a change in light emission color is suppressed. As described above, in the intermediate luminance range in which the visibility of the color is relatively high, the amount of drive current is constant, and the change in the emission color from the light emitting unit is suppressed.

  Therefore, in the first embodiment, an image display of a wide luminance dynamic range is realized, and in the intermediate luminance range in which the color visibility is relatively high, a change in emission color from the light emitting unit is suppressed.

  In the present embodiment, the current amount control value is made constant in the intermediate luminance range. However, in the intermediate luminance range, the current amount control value may be slightly changed in accordance with the light emission luminance to such an extent that the change in color is not an issue.

  Further, the intermediate luminance range in which the current amount control value is constant may be changed according to the brightness of the external light of the environment in which the image display device is installed.

  In addition, the intermediate luminance range where the current amount control value is constant corresponds to the luminance range (such as 10% to 90% of the input image data) when evaluating the color change in the evaluation standard and guidelines for liquid crystal projectors and displays. The luminance range may be set.

Second Embodiment
In the first embodiment, the configuration in which the entire light emission amount of the light emitting unit is subjected to global dimming control has been described, but in the second embodiment, the configuration in which the light emission amount of the light emitting unit 210 is locally locally controlled locally explain. Hereinafter, differences from the first embodiment will be mainly described.

  FIG. 7 is a block diagram showing the configuration of the image display apparatus according to the second embodiment. The image display device of FIG. 7 includes an image input unit 100, an image processing unit 200, a display unit 120, a light emitting unit 210, a light source drive unit 230, a light emission amount control unit 220, and an operation input unit 140. The same components as in FIG. 1 are denoted by the same reference numerals, and the detailed description thereof will not be repeated.

  The image processing unit 200 acquires an image feature amount for each frame of image data input from the image input unit 100. The image feature amount is acquired for each area block obtained by dividing the image of each frame into a plurality of area blocks. The image feature amount is, for example, a maximum value (maximum brightness value) or an average value (average brightness value) of pixel values (brightness values) of an image of one frame.

  The image processing unit 200 determines the light emission luminance for each light emission block of the light emission unit 210 based on the acquired image feature amount for each area block. A plurality of area blocks of the image and a plurality of light emitting blocks of the light emitting unit correspond to each other in the arrangement relationship. A light emission block corresponding to a region block having a small image feature amount is determined to have a low light emission luminance so as to reduce the light emission amount in order to display an image dark. A light emission block corresponding to a region block having a large image feature amount is determined to have a high light emission luminance so as to increase the light emission amount in order to display an image brightly. The image processing unit 200 outputs light emission luminance information indicating the determined light emission luminance for each light emission block to the light emission amount control unit 220.

  The light emitting unit 210 is a planar light emitting body in which a large number of LED light sources are disposed, and is a backlight which emits white light to the display unit 120 from the back side. The light emitting unit 210 is divided into a plurality of light emitting blocks, and the light emission amount of each light emitting block can be controlled independently of each other by the driving current output from the light source driving unit 230. The light emission amount of each light emission block of the light emission unit 210 is bright when the current amount of the drive current of the light emission block is large, and is dark when the current amount is small. The drive current is pulse width modulated, and the light emission amount is large when the pulse width is large, and the light emission amount is small when the pulse width is small.

  The light emission amount control unit 220 determines a current amount control value for controlling the current amount of the drive current of each light emission block of the light source, and a pulse width control value for controlling the pulse width of the drive current of each light emission block of the light source Control the brightness of each light emission block of the light source. Specifically, the light emission amount control unit 220 multiplies the light emission luminance of each light emission block determined by the image processing unit 200 by the light emission amount gain designated through the operation input unit 140, and Determine the final light emission brightness of Then, for each light emission block, the current amount control value and the pulse width control value are determined based on the determined light emission luminance. The light emission amount control unit 220 is, for example, a CPU, and controls the operation of the light source drive unit 230 by reading and executing a program from the ROM.

  The light source driving unit 230 is a driver circuit that drives the light source of the light emitting unit 210. The light source drive unit 230 controls the current amount of the drive current of each light emission block of the light emission unit 130 according to the current amount control value of each light emission block determined by the light emission amount control unit 220. Further, the pulse width of the drive current of each light emitting block of the light emitting unit 130 is controlled in accordance with the pulse width control value of each light emitting block determined by the light emitting amount control unit 220.

  FIG. 8 is a flow chart for explaining the operation of the image display device shown in FIG. First, in step S21, image data is input from the image output device to the image input unit 100.

  FIG. 9 shows an example of input image data. The image 510 is divided into three areas 601, 602 and 603 each having different pixel values. The area 601 is an area of an image (low intensity image) darker than the area 602, and the area 603 is an area of an image (high intensity image) brighter than the area 602.

  In step S22, the image processing unit 200 acquires an image feature amount for each area block of the image data input from the image input unit 100. For example, the image feature amount of the region block located in the area 601 of the image 510 is T4, the image feature amount of the region block located in the area 602 is T5, and the image feature amount of the region block located in the area 603 is T6.

  In step S23, the image processing unit 200 determines the light emission luminance of each light emission block of the light emission unit 210 according to the acquired image feature amount of each area block. FIG. 10 is a diagram showing an example of the correspondence between the image feature amount and the light emission luminance. In FIG. 10, the horizontal axis is the image feature amount of the input image data, and the vertical axis is the light emission luminance of each light emission block of the light emission unit 130. The light emission luminance is determined such that the light emission luminance is larger as the image feature amount is larger and the light emission luminance is smaller as the image feature amount is smaller.

  Then, the light emission amount control unit 220 multiplies the light emission brightness of each light emission block determined by the image processing unit 200 by the light emission amount gain set by the user to determine the final light emission luminance. For example, in the image 510, the light emission luminance Y4 corresponding to the image feature amount T4 of the area 601 is multiplied by the light emission amount gain, and the light emission luminance L4 after multiplication is determined. Further, the light emission luminance Y5 corresponding to the image feature amount T5 in the area 602 is multiplied by the light emission amount gain, and the light emission luminance L5 after multiplication is determined. Further, the light emission luminance Y6 corresponding to the image feature amount T6 of the area 603 is multiplied by the light emission amount gain, and the light emission luminance L6 after multiplication is determined.

  In step S24, the light emission amount control unit 220 determines the current amount control value and the pulse width control value of each light emission block of the light emission unit 210 from the light emission luminance of each final light emission block determined in step S23. The control value table used in the process of determining the current amount control value and the pulse width control value by the light emission amount control unit 150 is the same as that shown in FIG.

For example, when the light emission luminance L4 of the area 601 of the image 510 is 10 [cd / m ² ], the current amount control value of the light emission block corresponding to the area 601 is 20, and the pulse width control value is 150. When the light emission luminance L5 of the area 602 of the image 510 is 399 [cd / m ² ], the current amount control value of the light emission block corresponding to the area 602 is 20 and the pulse width control value is 3000. When the light emission luminance L6 of the area 603 of the image 510 is 1000 cd / m ² , the current amount control value of the light emission block corresponding to the area 603 is 50, and the pulse width control value is 3000.

  Next, in step S25, the light emission amount of each light emission block of the light emitting unit 210 is controlled using the current amount control value and the pulse width control value of each light emission block determined in step S24.

  For example, the light emission block that illuminates the area 601 of the image 510 is driven based on the current amount control value 20 and the pulse width control value 150. In addition, the light emission block that illuminates the area 602 of the image 510 is driven based on the current amount control value 20 and the pulse width control value 3000. That is, the area 601 and the area 602 are controlled by the same current amount control value 20 (controlled by the same amount of drive current). In the case where the light emitting unit 210 is a backlight of an LED light source, when the amount of driving current is changed, spectral characteristics change, so that the color of light emission is likely to change. However, since the area 601 and the area 602 of the image 510 have the same amount of drive current, the change of the spectral characteristic of each light emission block of the light emitting unit 210 is suppressed, and the change of the light emission color is suppressed. As described above, in the intermediate luminance range in which the visibility of the color is relatively high, the amount of drive current is constant, and the change in the emission color from the light emitting unit is suppressed.

  Therefore, in the second embodiment, as in the first embodiment, while the image display of the wide brightness dynamic range is realized, the change of the light emission color from the light emitting unit in the middle brightness range where the color visibility is relatively high. Is suppressed. Furthermore, in an area where an image in an intermediate luminance range with a relatively high color visibility is displayed, a change in emission color from the light emitting unit is suppressed.

(Other embodiments)
The present invention supplies a program that implements one or more functions of the above-described embodiments to a system or apparatus via a network or storage medium, and one or more processors in a computer of the system or apparatus read and execute the program. Can also be realized. The computer is configured of, for example, a processor such as a CPU or an MPU. It can also be implemented by a circuit (eg, an ASIC) that implements one or more functions. The computer program for realizing one or more functions of the above-described embodiments is also one of the present invention.

100 image input unit 110 image processing unit 120 display unit 130 light emitting unit 140 operation input unit 150 light emission amount control unit 160 light source drive unit

Claims (10)

A display unit for displaying an image based on the image data;
A light emitting unit that emits light to the display unit from the back side;
When the light emission brightness of the light emitting unit is in the low brightness range and in the high brightness range, current amount control is performed to control the current amount of the drive current of the light emitting unit, and the light emission brightness of the light emitting unit is the low brightness In the case of an intermediate luminance range between the range and the high luminance range, the pulse width control is performed to control the pulse width of the drive current of the light emitting portion without performing the current amount control And a control unit configured to control an amount of light emission.   The control unit performs the current amount control and performs the pulse width control when the light emission luminance of the light emitting unit is in a low luminance range and in a high luminance range. Image display device as described. The light emitting unit includes a plurality of light emitting blocks each capable of controlling an amount of light emission.
The image display apparatus according to claim 1, wherein the control unit performs the current amount control and the pulse width control for each of the plurality of light emitting blocks.   The said display part is a liquid crystal panel, The image display apparatus of any one of Claim 1 to 3 characterized by the above-mentioned.   The said light emission part has a LED light source, The image display apparatus of any one of Claim 1 to 4 characterized by the above-mentioned. A control method of an image display apparatus, comprising: a display unit configured to display an image based on image data; and a light emitting unit configured to emit light to the display unit from a back side,
When the light emission luminance of the light emitting unit is in the low luminance range and in the high luminance range, current amount control is performed to control the current amount of the drive current of the light emitting unit, and the light emission luminance of the light emitting unit is in the low luminance range In the above case, there is provided a control step of controlling the light emission amount of the light emitting unit by performing pulse width control for controlling the pulse width of the drive current of the light emitting unit without performing the current amount control. Control method of the image display device.   The control step performs the current amount control and performs the pulse width control when the light emission luminance of the light emitting unit is in a low luminance range and in a high luminance range. The control method of the image display apparatus as described. The light emitting unit includes a plurality of light emitting blocks each capable of controlling an amount of light emission.
The control method of the image display device according to claim 6 or 7, wherein the control step performs the current amount control and the pulse width control for each of the plurality of light emitting blocks.   The control method of an image display apparatus according to any one of claims 6 to 8, wherein the display unit is a liquid crystal panel.   The control method of the image display device according to any one of claims 6 to 9, wherein the light emitting unit has an LED light source.

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