WO2022249311A1

WO2022249311A1 - Display device and display method

Info

Publication number: WO2022249311A1
Application number: PCT/JP2021/019920
Authority: WO
Inventors: 秀平芳賀
Original assignee: 三菱電機株式会社
Priority date: 2021-05-26
Filing date: 2021-05-26
Publication date: 2022-12-01
Also published as: JPWO2022249311A1

Abstract

A display device (1) comprising: a display unit (11); a backlight (12) which is provided with a plurality of light sources and illuminates the display unit with light from the light sources; a display driver (13) which drives the display unit (11); and a signal processing unit (14) which displays an image on the display unit (11) on the basis of input image data. The display device (1) comprises signal lines (16) which connect the display driver (13) to the light sources of the backlight (12). The signal processing unit (14) applies signals which are for lighting and are output from the display driver (13) to the light sources provided to the backlight (12) through the signal lines (16), to thereby control the lighting of the light sources determined on the basis of the input image data.

Description

Display device and display method

The present disclosure relates to a display device and a display method.

Local dimming divides the backlight into a plurality of areas in a liquid crystal display device, and controls the luminance of the backlight for each area based on the feature value related to the luminance of the image to be displayed, thereby improving the contrast of the image display. It is a technology that improves For example, Patent Literature 1 describes a display device to which local dimming control is applied.

JP 2018-146750 A

Conventionally, local dimming was performed by a control circuit dedicated to the backlight, which was provided separately from the liquid crystal display control circuit. Therefore, there is a problem that a display device compatible with local dimming has a larger circuit scale than a display device not compatible with local dimming. Note that in the conventional display device described in Patent Document 1 as well, the control circuit dedicated to the backlight performs local dimming, and there is concern about an increase in circuit size.

The present disclosure is intended to solve the above problems, and an object thereof is to obtain a display device and a display method capable of implementing local dimming without providing a dedicated control circuit for the backlight.

A display device according to the present disclosure includes a display unit, a plurality of light sources, a backlight that illuminates the display unit with light from the light sources, a display driver that drives the display unit, and a display based on input image data. and a signal processing unit for displaying an image in the display device, the display device comprising a signal line connecting a display driver and a light source of the backlight, wherein the signal processing unit receives a lighting signal output from the display driver. By applying a signal to the light source of the backlight through the signal line, lighting of the light source determined based on the input image data is controlled.

According to the present disclosure, the signal processing unit applies the lighting signal output from the display driver to the light source of the backlight through the signal line, thereby turning on the light source determined based on the input image data. Control. With this, the display device according to the present disclosure can perform local dimming without providing a dedicated backlight control circuit.

2 is a block diagram showing the hardware configuration of the display device according to Embodiment 1; FIG. 3 is a configuration diagram showing partial configurations of a display unit and a display driver; FIG. 2 is a block diagram showing the functional configuration of the display device according to Embodiment 1; FIG. 4 is a flowchart showing a display method according to Embodiment 1; FIG. 4 is an explanatory diagram showing the relationship between a source driver and a backlight; FIG. 2 is a circuit diagram showing light emitting diodes (LEDs) included in the backlight; 4 is a table showing the relationship between the source voltage and the light emission luminance of an LED; 4 is a graph showing the relationship between gradation and source voltage; 7 is a graph showing the relationship between gradation and source voltage after correction; It is a graph which shows a gamma curve. 11A and 11B are block diagrams showing hardware configurations of signal processing units included in the display device according to Embodiment 1. FIG.

Embodiment 1.
FIG. 1 is a block diagram showing the hardware configuration of a display device 1 according to Embodiment 1. As shown in FIG. FIG. 2 is a configuration diagram showing a partial configuration of the display unit 11 and the display driver 13. As shown in FIG. The display device 1 is a device that performs local dimming control. In FIG. 1 , the display device 1 includes a display section 11 , a backlight 12 , a display driver 13 , a signal processing section 14 , an image output section 15 and signal lines 16 . The display unit 11 is illuminated by a backlight 12 and driven by a display driver 13 .

The backlight 12 has a plurality of light sources, is arranged behind the display unit 11, and illuminates the display unit 11 with light from the light sources. In the backlight 12, multiple light sources are arranged in a matrix. The light source is, for example, a light emitting diode (LED) that emits white light. In the following description, it is assumed that the plurality of light sources of the backlight 12 are LEDs. The display driver 13 is a driver that drives the display unit 11, and includes a source driver 13A and a gate driver 13B.

The display unit 11 includes a panel filled with a liquid crystal material and a glass substrate arranged on the back surface of this panel. In the panel, a plurality of TFTs (Thin Film Transistors) and pixels 20 shown in FIG. 2 are arranged in a matrix. Further, the glass substrate is provided with a plurality of scanning lines 17 for each pixel row of the plurality of pixels 20 and a plurality of data lines 18 for each pixel column of the plurality of pixels 20 . A scanning line 17 is a gate line for selecting a pixel row to which the gate voltage of the TFT 19 is applied. A data line 18 is a source line for applying a source voltage to pixels in a selected pixel row.

The TFT 19 is turned on or off according to the gate voltage applied to the scanning line 17 from the gate driver 13B. The source voltage applied from the source driver 13A to the data line 18 is held on the pixel 20 side by switching the TFT 19 from ON to OFF. The light transmittance of the pixel 20 changes according to the source voltage applied to the data line 18 .

The source driver 13A converts the digital control signal output from the signal processing unit 14 into an analog signal to generate a source voltage corresponding to the gradation value (eg, 0 to 255 gradation) of the image data. It is supplied to the pixels 20 of the display section 11 . Further, the source driver 13A converts the digital control signal output from the signal processing unit 14 into an analog signal, thereby generating an LED lighting voltage corresponding to the gradation value of the image data, and transmitting the voltage to the backlight 12 through the signal line 16. is applied to the LEDs of

The gate driver 13B generates a scanning signal for display according to the control signal output from the signal processing section 14, and outputs the generated scanning signal to the scanning line 17. In the local dimming control, divisions in the pixel column direction of pixel blocks irradiated with light from the LEDs of the backlight 12 are determined based on voltage signals applied to the scanning lines 17 by the gate driver 13B.

The signal processing unit 14 displays an image on the display unit 11 based on the image data input from the image output unit 15. In addition, the signal processing unit 14 applies the voltage from the display driver 13 to the light source of the backlight 12 through the signal line 16, thereby turning on the light source of the backlight 12 determined based on the input image data. Control. The image output unit 15 outputs image data stored in a storage device (not shown) or image data from an external device (not shown) to the signal processing unit 14 .

For example, the signal processing unit 14 analyzes the brightness of the image indicated by the input image data for each display area of the display unit 11, and determines the LED area of the backlight 12 that illuminates the display area. The signal processing unit 14 sets the maximum gradation in the display area to the brightness of the LED area of the backlight 12 that illuminates the display area. Thereby, the contrast ratio of the image displayed on the display unit 11 is improved. In addition, when the display area includes many pixels with low gradation, the LEDs of the backlight 12 set the luminance of the area of the LEDs of the backlight 12 that illuminates the display area to be low, so that the display area has pixels with high gradation. , the brightness of the LED area of the backlight 12 that illuminates the display area may be set high.

FIG. 3 is a block diagram showing the functional configuration of the display device 1. As shown in FIG. As shown in FIG. 3 , the signal processing section 14 includes an image processing section 141 and a timing control section 142 . The image processing unit 141 gamma-corrects the image data output from the image output unit 15 and outputs the gamma-corrected image data to the timing control unit 142 . Gamma correction is a process of correcting the luminance of an image represented by input image data so as to have a linear relationship.

The timing control unit 142 controls the timing of synchronizing the operation of displaying the gamma-corrected image data on the display unit 11 and the lighting and extinguishing of the LEDs of the backlight 12 . For example, the timing control unit 142 transmits a synchronization signal to the source driver 13A and the gate driver 13B for synchronizing the display of the gamma-corrected image data and the lighting of the LED. The pixel column direction of the pixel block illuminated by one LED in the backlight 12 is divided by the number of scanning lines 17 to which the gate driver 13B applies the gate voltage, and the pixel row direction is divided by the source driver 13A. It is divided by the number of data lines 18 to be applied.

4 is a flowchart showing a display method according to Embodiment 1. FIG.
The image processing unit 141 included in the signal processing unit 14 receives image data from the image output unit 15 and gamma-corrects an image represented by the input image data (step ST1). Subsequently, the image processing unit 141 converts the gamma-corrected image data into analog data. The image processing unit 141 applies a display voltage for displaying an image represented by image data after analog conversion on the display unit 11 and an LED lighting voltage for the backlight 12 for illuminating the image displayed on the display unit 11. is determined (step ST2).

In the local dimming control, the image processing unit 141 needs to change the brightness of the LEDs in each region of the backlight 12 according to the brightness of the image indicated by the input image data. In the conventional local dimming control, according to the brightness of the image indicated by the image data after analog conversion, LED brightness information in the area corresponding to the image in the backlight 12 is calculated, and a dedicated LED control circuit controls the LED brightness The light emission luminance of the LEDs in each region of the backlight 12 is changed according to the information.

As described above, the conventional display device that performs local dimming control has the problem that the circuit scale is larger than the display device that does not perform local dimming because it requires a dedicated LED control circuit. In contrast, the display device 1 does not require a dedicated LED control circuit by lighting the LEDs of the backlight 12 using the lighting voltage from the display driver 13 . As a result, the display device 1 suppresses an increase in circuit size due to local dimming control.

FIG. 5 is an explanatory diagram showing the relationship between the source driver 13A and the backlight 12. FIG. As shown in FIG. 5, the source driver 13A includes a plurality of lines 18A connected to the data lines 18 of the display unit 11, and signal lines 16A to 16C for lighting LEDs connected to the LEDs 121 of the backlight 12. Prepare. For example, the display unit 11 is a liquid crystal display with full high definition (FHD) resolution (1920×1080×RGB three colors), and the total number of LEDs 121 of the backlight 12 is 12 in the vertical direction and 32 in the horizontal direction. Assume that there are 384 of them.

A pixel block illuminated by light from one LED 121 of the backlight 12 has 90 pixels (=1080/12) in the pixel column direction when the display unit 11 has FHD resolution. The image processing unit 141 calculates the pixel block size A in the pixel column direction shown in FIG. 5 by dividing the gate voltage signal output by the gate driver 13B every 90 clocks. Thus, even without providing a dedicated LED control circuit, the image processing unit 141 can determine divisions in the pixel column direction of pixel blocks illuminated by light from one LED 121 of the backlight 12 . be.

In addition, the pixel block illuminated by the light from one LED 121 of the backlight 12 has 180 pixels in the pixel row direction (=1920×3 colors of RGB/32 pixels) when the display unit 11 has FHD resolution. . The image processing unit 141 divides the plurality of lines 18A connected to the plurality of data lines 18 of the display unit 11 into 180 lines by the source driver 13A, so that the pixel block size B in the pixel row direction shown in FIG. Calculate Thus, even without providing a dedicated LED control circuit, the image processing unit 141 can determine divisions in the pixel row direction of pixel blocks illuminated by light from one LED 121 of the backlight 12 . be. Note that the resolution of the display unit 11 and the total number of LEDs or the number of vertical and horizontal lights of the backlight 12 are examples.

The source driver 13A selects the maximum source voltage (peak voltage) among the source voltages applied to the data lines 18 of 180 lines in the pixel block 131A having a size A in the pixel column direction and a size B in the pixel row direction. , the selected source voltage is determined as the LED lighting voltage. The LED lighting voltage is output to the signal lines 16A to 16C and applied to the anode terminal of the LED 121. FIG. In the pixel blocks 131B and 131C, LED lighting voltages are similarly determined.

For example, to the LED 121A that illuminates the pixel block 131A, the maximum source voltage in the pixel block 131A is applied as a lighting voltage through the signal line 16A. Also, the maximum source voltage in the pixel block 131B is applied as a lighting voltage to the LED 121B that illuminates the pixel block 131B through the signal line 16B. The maximum source voltage in the pixel block 131C is applied as a lighting voltage to the LED 121C that illuminates the pixel block 131C through the signal line 16C.

Also, in conventional local dimming, a dedicated LED control circuit controls the current i flowing through the LEDs of the backlight 12 and the duty ratio to light the LEDs. In contrast, the display device 1 lights the LED by controlling only the voltage applied to the anode terminal of the LED. FIG. 6 is a circuit diagram showing the LEDs 121 included in the backlight 12. As shown in FIG. A signal line 16 from the source driver 13A is connected to the anode terminal of the LED 121 with a resistor R interposed. A current i flows through the LED 121 due to the lighting voltage Vp applied to the signal line 16 and the resistor R, and the current i is adjusted by controlling the lighting voltage Vp.

FIG. 7 is a table showing the relationship between the source voltage Vp and the emission luminance of the LED 121. As shown in FIG. The image processing unit 141 calculates the light emission luminance of the LED 121 corresponding to the source voltage Vp of each gradation of the image indicated by the input image data. Although the relationship between the light emission luminance of the LED and the current i flowing through the LED is normally proportional, there may be a characteristic deviation. Hereinafter, it is assumed that the light emission luminance of the LED and the current i flowing through the LED are in a proportional relationship, and even if there is a deviation between the characteristics of the two, the image quality of the image subjected to local dimming control is not affected. and
In general, there are two types of source voltages with respect to the common (COM), a positive voltage and a negative voltage. side voltage.

For example, when the lighting voltage Vf necessary for lighting the LED 121 is 6.0 (V) and the maximum current i flowing through the LED 121 is 100 (mA), the image processing unit 141 subtracts the lighting voltage Vf from the source voltage Vp. Then, the subtraction value (Vp-Vf) (V) is calculated. Subsequently, the image processing unit 141 calculates the current i (mA) flowing through the LED 121 using the formula (Vp−Vf)÷resistance (Ω). Furthermore, the image processing unit 141 calculates the brightness (%) of the LED 121 using the formula of the current i flowing through the LED 121 divided by the maximum current.

When the resistance R shown in FIG. 6 is 55.0 (Ω) and the gradation is “white”, the relationship between the source voltage Vp and the emission luminance of the LED is Vp = 11.5 (V), (Vp-Vf) = 5.5 (V), current i = 100 (mA), and the light emission luminance of the LED is 100 (%). Further, when the gradation is “gray” (128/255), the relationship between the source voltage Vp and the light emission luminance of the LED is Vp=8.5 (V), (Vp−Vf)=2.5 (V ), the current i=45.5 (mA), and the light emission luminance of the LED is 45.5 (%). When the gradation is "black", the relationship between the source voltage Vp and the light emission luminance of the LED is Vp=6.0 (V), (Vp-Vf)=0 (V), current i=0 (mA). , the emission luminance of the LED is 0 (%).
Note that this relationship between the source voltage Vp and the light emission luminance of the LED is an example.

Returning to the description of FIG.
When the display voltage and the LED lighting voltage are determined, the image processing unit 141 determines whether or not the gamma curve of the image to be displayed on the display unit 11 matches the target gamma curve (ideal gamma curve). (Step ST3). FIG. 8 is a graph showing the relationship between gradation and source voltage Vp. So far, it has been assumed that the source voltage Vp and the light emission luminance of the LED are in a proportional relationship, and that the source voltage Vp and the LED lighting voltage have the same value. However, in reality, as is apparent from the curve C1 in FIG. 8, there is a proportional relationship in the intermediate gradation area, but there is no proportional relationship in the low gradation area and the high gradation area. Therefore, if the gamma curve of the image is determined assuming that the gradation and the source voltage are in a proportional relationship, the gamma curve deviates from the ideal gamma curve.

Therefore, if the gamma curve of the image does not match the target gamma curve (step ST3; NO), the image processing section 141 returns to step ST1 and changes the voltage from the source driver 13A. For example, the image processing unit 141 performs normal gamma correction on the input image data, multiplies the gamma curve of the corrected image by the correction coefficient, and converts the gradation value multiplied by the correction coefficient into the gamma parameter. When the gamma parameter is set to "1", the 0 gradation and 255 gradation are multiplied by the correction coefficient "1", the correction coefficient is increased as the intermediate gradation is reached, and the correction is made gradually as the gradation shifts to the high gradation range. Decrease the coefficient.

FIG. 9 is a graph showing the relationship between the gradation and the corrected source voltage Vp. In FIG. 9, when the relationship between the gradation of the image to be displayed on the display unit 11 and the source voltage Vp is a curve C1, by multiplying the source voltage Vp by the correction coefficient for each gradation, The relationship of curve C2 is obtained in which the source voltage Vp is increased.

FIG. 10 is a graph showing gamma curves. In FIG. 10, a gamma curve D2 is a gamma curve obtained before performing the above-described correction on the image displayed on the display unit 11. FIG. The source driver 13A performs local dimming by applying the source voltage Vp to the LEDs of the backlight 12 to light them, and the relationship between the gradation and the source voltage Vp is a curve C1 shown in FIG. In the curve C1, the source voltage Vp in the intermediate gradation range is out of the proportional relationship. Therefore, in the gamma curve D2, the luminance in the intermediate gradation region is greatly depressed.
In the image with the gamma curve D2, the intermediate gradation becomes darker than the fineness of the black image due to local dimming, and the image cannot be viewed as a clear image.

The gamma curve D3 is a gamma curve that indicates the ideal relationship between gradation and luminance. The gamma curve D1 is a gamma curve obtained by correcting the relationship between the above-described gradation and the source voltage Vp for the image displayed on the display section 11 . As shown in FIG. 10, the correction coefficient is determined so that the gamma curve C1 and the gamma curve C3 have the same luminance ratio for each gradation. As a result, even when local dimming is performed by applying the source voltage Vp to the LEDs of the backlight 12 to turn them on, the display unit 11 has the same hierarchy and luminance relationship as the ideal gamma curve C3. Images can be displayed.

A case where the relationship between the gradation and the source voltage Vp is corrected for each gradation (processing of multiplying the source voltage Vp for each gradation by a correction coefficient) is shown. However, it is not necessary to perform correction at all gradations, and correction may be performed at intervals of several gradations, and the relationship between gradation and luminance between gradations without changing the source voltage Vp may be linearly interpolated. For example, it is assumed that the source voltage Vp varies linearly between grayscales not multiplied by the correction coefficient. Even in this way, it is possible to correct the relationship between the gradation and the source voltage Vp.

In the above correction, the source voltage Vp applied to the LEDs of the backlight 12 may be multiplied by a correction coefficient, or the display source voltage applied to the data lines 18 of the display unit 11 may be multiplied by the correction coefficient. You may

When the gamma curve of the image matches the target gamma curve (step ST3; YES), the timing control section 142 outputs a timing control signal to the display driver 13 so that the display voltage from the source driver 13A is applied to the data line 18. , and a lighting voltage is applied to the LEDs of the backlight 12 (step ST4). As a result, the operation of displaying the image indicated by the corrected image data on the display unit 11 and the lighting and extinguishing of the LEDs of the backlight 12 are performed in synchronization.

The functions of the image processing unit 141 and the timing control unit 142 in the signal processing unit 14 are realized by processing circuits. That is, the signal processing unit 14 includes a processing circuit for executing the processing from step ST1 to step ST4 shown in FIG. The processing circuit may be dedicated hardware, or may be a CPU that executes a program stored in memory.

FIG. 11A is a block diagram showing the hardware configuration that implements the functions of the signal processing unit 14. FIG. FIG. 11B is a block diagram showing a hardware configuration for executing software realizing the functions of the signal processing unit 14. As shown in FIG. 11A and 11B, the input interface 100 is an interface that relays image data output from the image output section 15 to the image processing section 141. FIG. The output interface 101 is an interface that relays control signals output from the timing control unit 142 to the display driver 13 .

If the processing circuit is the dedicated hardware processing circuit 102 shown in FIG. 11A, the processing circuit 102 may be, for example, a single circuit, multiple circuits, a programmed processor, a parallel programmed processor, an ASIC, an FPGA, or any of these. A combination of is applicable. The functions of the image processing unit 141 and the timing control unit 142 in the signal processing unit 14 may be realized by separate processing circuits, or these functions may be collectively realized by one processing circuit.

When the processing circuit is the processor 103 shown in FIG. 11B, the functions of the image processing unit 141 and the timing control unit 142 in the signal processing unit 14 are realized by software, firmware, or a combination of software and firmware. Note that software or firmware is written as a program and stored in the memory 104 .

The processor 103 implements the functions of the image processing unit 141 and the timing control unit 142 in the signal processing unit 14 by reading and executing the programs stored in the memory 104 . For example, the signal processing unit 14 includes a memory 104 for storing a program that, when executed by the processor 103, results in the processing of steps ST1 to ST4 shown in FIG. These programs cause the computer to execute the procedure or method of processing performed by the image processing unit 141 and the timing control unit 142 .

The memory 104 may be a computer-readable storage medium storing a program for causing a computer to function as the image processing section 141 and the timing control section 142. The memory 104 corresponds to, for example, nonvolatile or volatile semiconductor memory such as RAM, ROM, flash memory, EPROM, EEPROM, magnetic disk, flexible disk, optical disk, compact disk, mini disk, DVD, and the like.

A part of the functions of the image processing unit 141 and the timing control unit 142 in the signal processing unit 14 may be realized by dedicated hardware, and a part may be realized by software or firmware. For example, the image processing unit 141 realizes its function by the processing circuit 102, which is dedicated hardware, and the timing control unit 142 realizes its function by the processor 103 reading and executing a program stored in the memory 104. may be realized. As such, the processing circuitry may implement the above functions in hardware, software, firmware, or a combination thereof.

As described above, in the display device 1 according to Embodiment 1, the signal processing unit 14 applies the lighting signal output from the display driver 13 to the LEDs 121 of the backlight 12 through the signal line 16. , controls lighting of the LED 121 determined based on the input image data. As a result, the display device 1 can perform local dimming without providing a dedicated backlight control circuit.

In the display device 1 according to Embodiment 1, the display unit 11 includes a plurality of pixels 20 arranged in a matrix and provided for each pixel row in the plurality of pixels 20, and selects a pixel row to which a gate voltage is applied. and a plurality of data lines 18 provided for each pixel column in the plurality of pixels 20 and for applying a source voltage to pixels in a selected pixel row. The display driver 13 has a source driver 13A that applies source voltages to the plurality of data lines 18 and a gate driver 13B that applies gate voltages to the plurality of scanning lines 17 . A signal line 16 connects the source driver 13A and the LED 121 of the backlight 12 . The signal processing unit 14 applies the source voltage output from the source driver 13A to the LEDs 121 of the backlight 12 through the signal line 16 . As a result, the display device 1 can perform local dimming without providing a dedicated backlight control circuit.

In the display device 1 according to Embodiment 1, the signal processing section 14 changes the source voltage output from the source driver 13A so that the gamma curve of the image displayed on the display section 11 matches the target gamma curve. Thereby, the gamma curve of the image to be displayed on the display unit 11 can be corrected to the target gamma curve.

In the display device 1 according to Embodiment 1, the signal processing section 14 changes the source voltage output from the source driver 13A for each gradation of the image to be displayed on the display section 11 . Thereby, the gamma curve of the image to be displayed on the display unit 11 can be corrected to the target gamma curve.

In the display device 1 according to the first embodiment, the signal processing unit 14 changes the source voltage output from the source driver 13A every several gradations of the image to be displayed on the display unit 11, and changes the gradation without changing the source voltage. linearly interpolate the relationship between gradation and luminance. Thereby, the gamma curve of the image to be displayed on the display unit 11 can be corrected to the target gamma curve.

In the display device 1 according to Embodiment 1, the signal processing unit 14 performs pixel block illumination in the pixel column direction based on the gate voltage signal applied to the scanning line 17 from the gate driver 13B. Decide on a break. This makes it possible to determine a pixel block to be illuminated by local dimming.

In the display device 1 according to Embodiment 1, the cathode terminal of the LED 121 in the backlight 12 is grounded, and the signal line 16 is connected to the anode terminal via a resistor.
The LED 121 can be lit with the source voltage output from the source driver 13A without providing a dedicated LED control circuit.

It should be noted that any component of the embodiment can be modified or any component of the embodiment can be omitted.

The display device according to the present disclosure can be used, for example, as a display device for in-vehicle equipment.

1 display device, 11 display unit, 12 backlight, 13 display driver, 13A source driver, 13B gate driver, 14 signal processing unit, 15 image output unit, 16, 16A to 16C signal lines, 17 scanning lines, 18 data lines, 18A lines, 19 TFTs, 20 pixels, 100 input interface, 101 output interface, 102 processing circuit, 103 processor, 104 memory, 121, 121A to 121C LEDs, 131A to 131C pixel blocks, 141 image processing section, 142 timing control section.

Claims

a display unit;
a backlight having a plurality of light sources and illuminating the display section with light from the light sources;
a display driver that drives the display unit;
a signal processing unit that displays an image on the display unit based on input image data;
A display device comprising
a signal line connecting the display driver and the light source of the backlight;
The signal processing unit controls lighting of the light source determined based on input image data by applying a voltage from the display driver to the light source of the backlight through the signal line. A display device characterized by:
The display unit includes a plurality of pixels arranged in a matrix, a plurality of scanning lines provided for each pixel row in the plurality of pixels for selecting a pixel row to which a voltage is applied, and the plurality of pixels. and a plurality of data lines provided for each pixel column in and for applying a voltage to the pixels of the selected pixel row,
The display driver has a source driver that applies voltages to the plurality of data lines and a gate driver that applies voltages to the plurality of scanning lines,
the signal line connects the source driver and the light source of the backlight;
2. The display device according to claim 1, wherein the signal processing section applies a voltage from the source driver to the light source of the backlight through the signal line.
3. The display device according to claim 2, wherein the signal processing section changes the voltage from the source driver so that the gamma curve of the image to be displayed on the display section matches a target gamma curve.
4. The display device according to claim 3, wherein the signal processing section changes the voltage from the source driver for each gradation of an image to be displayed on the display section.
The signal processing unit changes the voltage from the source driver every several gradations of an image to be displayed on the display unit, and changes the relationship between gradation and luminance between gradations without changing the voltage from the source driver. 4. The display device according to claim 3, wherein the linear interpolation is performed on .
2. The signal processing unit determines, based on the voltage signal applied to the scanning line by the gate driver, the division of the pixel blocks illuminated by the light from the light source in the pixel column direction. 6. The display device according to any one of claims 1 to 5.
the light source in the backlight is a light emitting diode;
6. The display device according to any one of claims 2 to 5, wherein the light emitting diode has a cathode terminal grounded, and the signal line is connected to an anode terminal via a resistor.
a plurality of pixels arranged in a matrix; a plurality of scanning lines provided for each pixel row in the plurality of pixels for selecting a pixel row to which a voltage is applied; a display unit provided with a plurality of data lines for applying voltages to pixels in a selected pixel row;
a backlight having a plurality of light sources and illuminating the display section with light from the light sources;
a source driver that applies a voltage to the plurality of data lines;
a signal processing unit that displays an image on the display unit based on input image data;
A display method for a display device comprising
a step in which the signal processing unit gamma-corrects the relationship between gradation and luminance in the input image data;
determining, by the source driver, voltages to be applied to the plurality of data lines and voltages to be applied to the light source based on gamma-corrected image data;
a step in which the signal processing unit determines whether or not the gamma curve of the image to be displayed on the display unit matches a target gamma curve;
changing the voltage from the source driver if both gamma curves do not match;
A display method comprising: when the gamma curves match, the signal processing unit causes the display unit to display an image, and controls lighting of the light source of the backlight.