JP6830244B2 - Display device and its control method - Google Patents

Description

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

In a display device such as a liquid crystal panel, a technique for controlling the voltage applied to the panel in order to optimize the brightness of the panel is known (see, for example, Patent Document 1).

On the other hand, HDR (High Dynamic Range) is attracting attention as a new method with an expanded luminance dynamic range. Specifically, the method of the luminance range supported by the conventional video signals is called SDR (Standard Dynamic Range), and the maximum luminance value is 100 nits, whereas the maximum luminance value is 1000 nits or more in HDR. It is expected that the brightness value will be increased. HDR is being standardized in SMPTE (Society of Motion Picture & Television Engineers) and ITU-R (International Telecommunication Union Radiocommunication Sector).

JP-A-2009-145866

However, when reproducing such an HDR video signal, it may not be possible to realize a display using an appropriate luminance resolution because the display gradation of the panel is not properly set.

Therefore, an object of the present disclosure is to provide a display device or a control method thereof that can realize a display using an appropriate luminance resolution.

The display device according to one aspect of the present disclosure is a display device that displays an image based on a video signal, and the gamma of the display panel according to the display panel for displaying the image and the luminance dynamic range of the image signal. The control unit includes a control unit that changes the characteristics, and the control unit determines whether the luminance dynamic range of the video signal is the first luminance dynamic range or the second luminance dynamic range wider than the first luminance dynamic range. When the determination is made and the luminance dynamic range of the video signal is the first luminance dynamic range, the gamma value indicating the gamma characteristic of the display panel is set to the first gamma value, and the luminance dynamic range of the video signal is the said. In the case of the second luminance dynamic range, the gamma value is set to a second gamma value larger than the first gamma value .

The present disclosure can provide a display device or a control method thereof that can realize a display using an appropriate luminance resolution.

FIG. 1 is a diagram showing an example of a display device according to the first embodiment. FIG. 2 is a block diagram of the display device according to the first embodiment. FIG. 3 is a block diagram of the control unit according to the first embodiment. FIG. 4 is a flowchart showing the operation of the display device according to the first embodiment. FIG. 5A is a diagram showing gamma characteristics for SDR according to the first embodiment. FIG. 5B is a diagram showing gamma characteristics for HDR according to the first embodiment. FIG. 6 is a diagram showing a configuration for generating a gradation voltage according to the first embodiment. FIG. 7 is a diagram showing the relationship between the input signal, the display luminance, the gradation voltage, and the transmittance according to the first embodiment. FIG. 8 is a diagram showing a PQ curve and a gamma characteristic for SDR according to the first embodiment. FIG. 9A is a diagram showing a PQ curve in a low luminance range and a gamma characteristic for SDR according to the first embodiment. FIG. 9B is a diagram showing a PQ curve in a high luminance range and a gamma characteristic for SDR according to the first embodiment. FIG. 10A is a diagram showing the resolution of the PQ curve in the low luminance range according to the first embodiment. FIG. 10B is a diagram showing the resolution of the gamma characteristic for SDR in the low luminance range according to the first embodiment. FIG. 11 is a diagram showing gamma characteristics for HDR according to the second embodiment. FIG. 12 is a diagram showing a low gradation portion of the gamma characteristic for HDR according to the second embodiment. FIG. 13 is a block diagram of the control unit according to the second embodiment. FIG. 14 is a flowchart showing the operation of the display device according to the second embodiment. FIG. 15 is a diagram showing a reference voltage for HDR according to the second embodiment. FIG. 16 is a diagram showing corrected gamma characteristics for HDR according to the second embodiment. FIG. 17 is a diagram showing a corrected reference voltage for HDR according to the second embodiment. FIG. 18 is a diagram showing a corrected reference voltage for HDR according to the second embodiment. FIG. 19 is a diagram showing corrected gamma characteristics for SDR according to the second embodiment. FIG. 20 is a diagram showing a corrected reference voltage for SDR according to the second embodiment.

Hereinafter, embodiments will be described in detail with reference to the drawings as appropriate. However, more detailed explanation than necessary may be omitted. For example, detailed explanations of already well-known matters and duplicate explanations for substantially the same configuration may be omitted. This is to avoid unnecessary redundancy of the following description and to facilitate the understanding of those skilled in the art.

It should be noted that the inventors intend to limit the subject matter described in the claims by those skilled in the art by providing the accompanying drawings and the following description in order to fully understand the present disclosure. is not it.

(Embodiment 1)
Hereinafter, the present embodiment will be described with reference to FIGS. 1 to 10B.

[Display device configuration]
First, the overall configuration of the display device 100 according to the present embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a diagram showing the appearance of the display device 100. For example, the display device 100 is a flat panel display type liquid crystal television receiver.

FIG. 2 is a block diagram of the display device 100. As shown in FIG. 2, the display device 100 is a display device that displays an image based on the image signal 111, and includes a display panel 101, a source driver 102, a gate driver 103, and a control unit 104.

The display panel 101 is a liquid crystal panel for displaying an image, and includes a plurality of pixel portions (not shown) arranged in a matrix.

The source driver 102 supplies a data signal indicating a pixel drive voltage corresponding to the emission brightness to each of a plurality of pixel portions in the display panel 101 arranged in the row via a data line provided for each row. To do.

The gate driver 103 supplies a control signal for controlling the display operation to each of a plurality of pixel units in the display panel 101 arranged in the row via a control line provided for each row.

The control unit 104 controls the source driver 102 and the gate driver 103 based on the video signal 111 acquired from the outside. The control unit 104 is composed of, for example, a storage unit (not shown) for storing the control program and an arithmetic processing unit (not shown) for executing the control program. The video signal 111 is a signal for forming an image on the display panel 101, and is output from a recording medium such as a DVD (Digital Versaille Disc) or a broadcasting device such as a terrestrial digital broadcast or a satellite digital broadcast. ..

[Structure of control unit 104]
Next, the configuration of the control unit 104 will be described with reference to FIG. In the present embodiment, the control unit 104 changes the gamma characteristic of the display panel 101 according to the luminance dynamic range (SDR or HDR) of the video signal 111.

FIG. 3 is a block diagram of the control unit 104. As shown in FIG. 3, the control unit 104 includes a switching unit 121, a curve conversion unit 122, a signal processing unit 123, and an inverse gamma conversion unit 124. In addition, the display device 100 further includes a DA converter 105.

The switching unit 121 changes the conversion process when generating the linear video signal 112 according to the luminance dynamic range of the video signal 111. Specifically, the switching unit 121 switches the conversion curve used by the curve conversion unit 122 depending on whether the video signal 111 is SDR or HDR. Further, the gamma characteristic of the display panel 101 is changed according to the luminance dynamic range of the video signal 111. Specifically, the switching unit 121 switches the gamma curve used by the inverse gamma conversion unit 124 according to whether the video signal 111 is SDR or HDR, and the reference voltage 115 output by the DA converter 105. To switch.

The curve conversion unit 122 generates a linear video signal 112 by converting the video signal 111 based on a predetermined conversion curve. Specifically, when the video signal 111 is HDR, it is converted into a linear video signal 112 based on the PQ curve. The signal processing unit 123 generates the video signal 113 by performing digital signal processing such as color correction on the video signal 112. The inverse gamma conversion unit 124 performs inverse gamma conversion of the video signal 113 to generate, for example, an input signal 114 which is a 10-bit code.

The DA converter 105 generates a plurality of reference voltages 115, which are a plurality of analog voltages used for gamma conversion in the source driver 102.

The source driver 102 generates a data signal 116 by performing gamma conversion of the input signal 114 using the reference voltage 115, and supplies the generated data signal 116 to the display panel 101.

[motion]
Next, the operation of the display device 100 will be described with reference to FIGS. 4 and 5. FIG. 4 is a flowchart showing the operation flow of the display device 100.

First, the switching unit 121 determines whether the video signal 111 is SDR or HDR (S101). For example, the video signal 111 includes control information (metadata) indicating whether the video signal 111 is an SDR video signal or an HDR video signal. The switching unit 121 determines whether the video signal 111 is SDR or HDR by referring to the control information.

Then, when the video signal 111 is SDR (No in S101), the curve conversion unit 122 generates a linear video signal 112 by converting the video signal 111 based on a normal curve (S102). Next, the signal processing unit 123 generates the video signal 113 by performing digital signal processing such as color correction on the video signal 112 (S103). Then, the switching unit 121 sets the gamma characteristic of the display panel 101 to the gamma characteristic for SDR.

On the other hand, when the video signal 111 is HDR (Yes in S101), the curve conversion unit 122 generates a linear video signal 112 by converting the video signal 111 based on the PQ curve (S104). Next, the signal processing unit 123 generates the video signal 113 by performing digital signal processing such as color correction on the video signal 112 (S105). Then, the switching unit 121 sets the gamma characteristic of the display panel 101 to the gamma characteristic for HDR.

FIG. 5A is a diagram showing an example of gamma characteristics for SDR. FIG. 5B is a diagram showing an example of gamma characteristics for HDR. As shown in FIG. 5A, a 2.2 gamma characteristic (gamma value = 2.2) is used as the gamma characteristic for SDR, and a cube gamma characteristic (gamma value = 3.0) is used as the gamma characteristic for HDR. ) Is used. That is, the switching unit 121 sets the gamma value of the gamma characteristic for HDR to a value larger than the gamma value of the gamma characteristic for SDR.

Specifically, when the video signal 111 is SDR (No in S101), the inverse gamma conversion unit 124 performs an inverse gamma conversion corresponding to the gamma characteristic for SDR on the video signal 112 to perform an input signal. Generate 114 (S106). The DA converter 105 generates a plurality of reference voltages 115 corresponding to gamma conversion for SDR (S107). Next, the source driver 102 performs gamma conversion for SDR by converting the input signal 114 into a data signal 116 using the generated reference voltage 115 for SDR, and displays the obtained data signal 116 on the display panel 101. It is supplied to the pixel portion inside (S108).

On the other hand, when the video signal 111 is HDR (Yes in S101), the inverse gamma conversion unit 124 generates the input signal 114 by performing the inverse gamma conversion corresponding to the gamma characteristic for HDR on the video signal 112. (S109). The DA converter 105 generates a plurality of reference voltages 115 corresponding to gamma conversion for HDR (S110). Next, the source driver 102 performs HDR gamma conversion by converting the input signal 114 into the data signal 116 using the generated reference voltage 115 for HDR, and displays the obtained data signal 116 in the display panel 101. It is supplied to the pixel portion of (S108).

[motion]
Next, the operations of the DA converter 105 and the source driver 102 will be described with reference to FIGS. 6 and 7. FIG. 6 is a diagram showing a configuration regarding a reference voltage 115 in the DA converter 105 and the source driver 102. FIG. 7 is a diagram showing the relationship between the input signal 114, the display luminance L, the gradation voltage V, and the transmittance T.

In the example shown in FIG. 6, the DA converter 105 generates nine reference voltages 115 on the negative side and nine on the positive side, respectively. Specifically, the DA converter 105 can output a reference voltage 115 of an arbitrary value based on the input voltage set value. For example, a voltage set value for SDR and a voltage set value for HDR are stored in advance in a storage unit (not shown) in the control unit 104. When the video signal 111 is SDR, the switching unit 121 inputs the voltage set value for SDR to the DA converter 105, and when the video signal 111 is HDR, the switching unit 121 inputs the voltage set value for HDR to DA. Input to the converter 105. As a result, a reference voltage 115 having a different value is generated depending on whether the video signal 111 is SDR or HDR.

The source driver 102 can generate a gradation voltage corresponding to each of the digital values of the input signal 114 by using the plurality of reference voltages 115. Note that FIG. 6 shows an example in which 8-bit (256 ways) gradation voltages are generated using nine reference voltages 115.

Then, the source driver 102 supplies the gradation voltage corresponding to the digital value of the input signal 114 to the corresponding pixel unit as the data signal 116. The pixel unit emits light with a brightness corresponding to the data signal 116.

That is, as shown in FIG. 7, the transmittance T of the liquid crystal panel, that is, the display luminance L is determined according to the gradation voltage V. Further, the gradation voltage is changed by changing the reference voltage 115. As a result, the gamma characteristic of the display panel 101 can be changed by changing the reference voltage 115 as described above.

[Effects, etc.]
As described above, the display device 100 according to the present embodiment switches the gamma characteristic of the display panel 101 according to whether the video signal 111 is SDR or HDR. As a result, it is possible to realize a display using an appropriate luminance resolution for the HDR video signal.

On the other hand, for example, when the conventional gamma curve for SDR (gamma value = 2.2) is used for the HDR video signal, the following problems occur.

FIG. 8 is a diagram showing a PQ curve for HDR (SMPTE ST 2084) defined by SMPTE and a gamma curve for SDR (gamma value = 2.2). 9A is an enlarged view of the low-luminance range of FIG. 8, and FIG. 9B is an enlarged view of the high-luminance range of FIG. FIG. 10A is a diagram showing the resolution of the PQ curve in the low luminance range, and FIG. 10B is a diagram showing the resolution of the gamma curve (gamma value = 2.2) in the low luminance range.

As shown in FIG. 9A, in the low luminance range, the resolution of the gamma curve is lower than the resolution of the PQ curve, and sufficient resolution is not obtained. Further, as shown in FIG. 9B, in the high luminance range, the resolution of the gamma curve is higher than the resolution of the PQ curve, which is an excessive resolution. Specifically, as shown in FIG. 10A, 13 gradations are assigned to the low luminance range of 5 to 6 bits in the PQ curve, whereas in the gamma curve (gamma value = 2.2). Only 7 gradations can be assigned.

On the other hand, in the display device 100 according to the present embodiment, by using the gamma characteristic for HDR as shown in FIG. 5B, the resolution in the low luminance range is increased as compared with the case where the gamma characteristic of SDR is used. , The resolution in the high luminance range can be reduced. Thereby, the above problem can be solved.

Further, in the present embodiment, the above problem is solved by changing the gamma characteristic of the display panel 101. Therefore, it is not necessary to increase the gradation of the display panel 101, and the resolution in the low luminance range can be increased by a simple configuration. In addition, it is possible to support high-quality reproduction of HDR video, which is expected to have a higher bit depth.

For example, the reference voltage 115 can be changed by a simple configuration in which different voltage setting values are input to the DA converter 105 during SDR and HDR, so the gamma characteristics can be changed without the need to add a large circuit. can do.

(Embodiment 2)
Hereinafter, the present embodiment will be described with reference to FIGS. 11 to 20. In the present embodiment, a modification of the display device according to the first embodiment will be described.

[Task]
FIG. 11 is a diagram showing an example of a gamma characteristic of the 3.5th power (gamma value = 3.5) for HDR. FIG. 12 is an enlarged view of a low gradation portion of the gamma characteristic shown in FIG.

Here, in the liquid crystal display panel, the transmittance of the liquid crystal does not become zero. As a result, as shown in FIG. 12, the low-gradation brightness displayed on the display panel becomes higher than the ideal characteristic. The brightness actually displayed on the display panel depends on the characteristics of the display panel, and as shown in FIG. 12, different display panels have different characteristics.

As described above, in the actual display panel, the slope of the graph becomes a characteristic in the low gradation. That is, the original brightness difference of the low-gradation portion of the image is compressed. As a result, the dark pattern becomes harder to see than the original image.

On the other hand, as a method of solving this, it is also possible to make a low-gradation pattern easier to see by applying a gain to the image by signal processing. However, when the digital signal processing calculation is performed, there arises a problem that the number of gradations decreases and the gradation property of the image is lost in the gradations other than the dark part where a gain of 1 or less is applied.

In this embodiment, a display device capable of solving such a problem will be described.

[Constitution]
FIG. 13 is a block diagram showing a configuration of the control unit 104A according to the present embodiment. The control unit 104A shown in FIG. 13 includes a brightness determination unit 125 in addition to the configuration of the control unit 104 shown in FIG. Further, the function of the switching unit 121A is different from that of the switching unit 121.

The luminance determination unit 125 determines the luminance of the video signal 111. Specifically, the brightness determination unit 125 determines APL (Average Picture Level) indicating the average brightness (average brightness) in the picture of the video signal 111.

In addition to the function of the switching unit 121, the switching unit 121A switches the reference voltage 115 generated by the DA converter 105 according to the APL. Specifically, when the APL is less than a predetermined reference value, the switching unit 121A increases the reference voltage 115 for low gradation generated by the DA converter 105.

[motion]
FIG. 4 is a flowchart showing the operation flow of the display device 100. First, the switching unit 121A determines whether the video signal 111 is SDR or HDR (S121). When the video signal 111 is HDR (Yes in S121), the switching unit 121A determines whether the APL of the video signal 111 is less than the reference value (S122). For example, the reference value is about 5% of the maximum brightness. For example, in the example shown in FIG. 11, since the maximum brightness is 1000 nits (cd / m ² ), the reference value is set to the value of the input signal (about 430) corresponding to 100 nits. The maximum brightness in the picture may be used instead of APL.

When the APL is equal to or higher than the reference value (No in S122), the DA converter 105 generates a plurality of reference voltages 115 corresponding to the gamma conversion for HDR based on the instruction of the switching unit 121A (S123). Next, the source driver 102 performs gamma conversion for HDR by converting the input signal 114 into a data signal 116 using the generated reference voltage 115 for HDR, and displays the obtained data signal 116 on the display panel 101. It is supplied to the inner pixel portion (S128).

Although the description is omitted here, linear conversion, various signal processing, and inverse gamma conversion are performed as in the first embodiment.

On the other hand, when the APL is less than the reference value (Yes in S122), the DA converter 105 generates a plurality of reference voltages 115 corresponding to the corrected gamma conversion for HDR based on the instruction of the switching unit 121A (S124). .. Next, the source driver 102 performs gamma conversion for HDR corrected by converting the input signal 114 into a data signal 116 using the generated reference voltage 115 for HDR, and obtains the data signal 116. Is supplied to the pixel portion in the display panel 101 (S128).

FIG. 15 is a diagram showing an example of a reference voltage (gamma voltage) for HDR. FIG. 15 shows an example when a reference voltage of 9 gradations × 2 is used. Here, since the liquid crystal display panel is AC driven, the reference voltage on the + side and the-side is set around the VCOM voltage. Also, except for the error, the + side and the-side are symmetrical with respect to the VCOM voltage.

FIG. 16 is a diagram showing an example of a normal gamma characteristic for HDR and a corrected gamma characteristic for HDR. FIG. 16 shows the characteristics of two types of display panels, panel A and panel B.

FIG. 17 shows an example of the normal and corrected reference voltage of the panel A, and FIG. 18 shows an example of the normal and corrected reference voltage of the panel B. Note that FIGS. 17 and 18 show only the characteristics on the + side.

As shown in FIG. 16, in the present embodiment, the reference voltage for low gradation increases, and as a result, the inclination of the low gradation portion of the gamma characteristic becomes large. Here, the low gradation is a gradation portion in which the value of the input signal or the luminance value is lower than a predetermined value. Specifically, it is a region equal to or less than the black brightness or the brightness value around it (for example, about several times the black brightness). For example, black brightness is determined by the maximum brightness and the contrast ratio.

The panel A is, for example, a VA (Virtual Element) type display panel, and the inclination of the input signal value around 64 to 128 lies. The contrast ratio is 5000: 1. In this case, the black brightness is about 1000 nits / 5000 = 0.2 nits.

The panel B is, for example, an IPS (In Place Switching) type display panel, and the inclination of the input signal value around 64 to 160 lies. Also, the contrast ratio is 1000: 1. In this case, the black brightness is about 1000 nits / 1000 = 1 nits.

In the example shown in FIG. 16, the black brightness and the reference voltage and the gamma characteristic of the peripheral region are changed, and the gamma characteristic is continuously changed from the low gradation portion to the high gradation portion. The reference voltage and gamma characteristics have been changed up to the region around the tuning portion (input signal value of about 256).

Further, in step S121 shown in FIG. 14, when the video signal 111 is SDR (No in S121), the switching unit 121A determines whether the APL of the video signal 111 is less than the reference value (S125). For example, this reference value is about 10% of the maximum brightness, which is different from the reference value used in step S122.

When the APL is equal to or higher than the reference value (No in S125), the DA converter 105 generates a plurality of reference voltages 115 corresponding to the gamma conversion for SDR based on the instruction of the switching unit 121A (S126). Next, the source driver 102 performs gamma conversion for SDR by converting the input signal 114 into a data signal 116 using the generated reference voltage 115 for SDR, and displays the obtained data signal 116 on the display panel 101. It is supplied to the pixel portion inside (S128).

On the other hand, when the APL is less than the reference value (Yes in S125), the DA converter 105 generates a plurality of reference voltages 115 corresponding to the corrected gamma conversion for SDR based on the instruction of the switching unit 121A (S127). .. Next, the source driver 102 performs gamma conversion for SDR corrected by converting the input signal 114 into a data signal 116 using the generated reference voltage 115 for SDR, and obtains the data signal 116. Is supplied to the pixel portion in the display panel 101 (S128).

FIG. 19 is a diagram showing an example of a normal gamma characteristic for SDR and a corrected gamma characteristic for SDR. FIG. 20 shows an example of a normal and corrected reference voltage in this case. Note that FIG. 20 shows only the characteristics on the + side.

For example, a look-up table showing a plurality of reference voltages 115 is provided for each of the normal HDR, the corrected HDR, the normal SDR, and the corrected SDR, and the lookup table is used. The reference voltage 115 is switched.

[Effects, etc.]
As described above, in the present embodiment, the reference voltage 115 is controlled according to the APL of the video signal. Specifically, the display device 100 determines that the video signal having a low APL is a video signal in which the gradation expression of the dark part is important, and changes the reference voltage corresponding to the dark part. More specifically, the display device 100 changes the reference voltage so that the slope of the input signal-luminance characteristic in the dark portion becomes large. Thereby, the visibility of the pattern in the dark part can be improved.

Further, by using the method of changing the reference voltage 115, it is not necessary to change the parts of the liquid crystal panel, and the cost increase can be suppressed. Further, the influence on the intermediate gradation can be reduced.

Further, in HDR, since many gradations are assigned to low gradations, it is particularly effective to use the method of the present embodiment for HDR.

In the above description, the correction processing for correcting the low gradation is performed for each of the HDR and the SDR, but the correction processing may be performed only in either case.

Further, in the above description, in the configuration where the reference voltage 115 is changed according to HDR or SDR, an example of further performing correction processing for correcting low gradation has been described, but only correction processing for correcting low gradation has been described. May be done.

[Modification example]
Although the display device according to the embodiment of the present disclosure has been described above, the present disclosure is not limited to this embodiment.

For example, in the above description, an example of switching the gamma characteristic according to SDR and HDR has been described. Disclosure is applicable. Further, the present disclosure can be applied even when there are three or more types of video signals having such different luminance dynamic ranges. In this case, different gamma characteristics are used depending on the type of video signal. For example, the wider the luminance dynamic range (the higher the maximum luminance), the higher the gamma value is controlled.

Further, the gamma characteristics for SDR and HDR shown above are examples, and the gamma value is not limited to the above values. That is, different gamma characteristics may be used for SDR and HDR, and for example, the gamma value for HDR is set higher than the gamma value for SDR. That is, a gamma curve deeper than the gamma curve for SDR is used for HDR.

Further, in the above description, an example of generating a linear video signal based on a predetermined curve according to the SDR and HDR has been described, but the present invention is not limited to this, and the SDR video signal is converted into a linear video signal. It may be sent to the signal processing unit 123 as it is without being subjected to various signal processing, while the HDR video signal may be converted into a curve equivalent to the SDR video signal. Further, only the HDR video signal may be converted into a linear video signal.

Further, the number of bits of the digital signal, the number of reference voltages, and the like shown above are examples, and are not limited to the above.

Further, each processing unit included in the display device according to the above embodiment is typically realized as an LSI which is an integrated circuit. These may be individually integrated into one chip, or may be integrated into one chip so as to include a part or all of them.

Further, the integrated circuit is not limited to the LSI, and may be realized by a dedicated circuit or a general-purpose processor. An FPGA (Field Programmable Gate Array) that can be programmed after the LSI is manufactured, or a reconfigurable processor that can reconfigure the connection and settings of circuit cells inside the LSI may be used.

That is, in each of the above-described embodiments, each component may be configured by dedicated hardware or may be realized by executing a software program suitable for each component. Each component may be realized by a program execution unit such as a CPU or a processor reading and executing a software program recorded on a recording medium such as a hard disk or a semiconductor memory.

Further, the present disclosure may be realized as a control method of a display device including a characteristic step executed by the display device.

Further, the circuit configuration shown in the circuit diagram is an example, and the present disclosure is not limited to the circuit configuration.

Further, the division of the functional block in the block diagram is an example, and a plurality of functional blocks can be realized as one functional block, one functional block can be divided into a plurality of functional blocks, and some functions can be transferred to other functional blocks. You may. Further, the functions of a plurality of functional blocks having similar functions may be processed by a single hardware or software in parallel or in a time division manner.

The processing procedure shown in the above flowchart is an example, and may be in an order other than the above. Further, a part of the above steps may be executed at the same time (parallel) as other steps.

Although the display device according to one or more aspects has been described above based on the embodiment, the present disclosure is not limited to this embodiment. As long as the purpose of the present disclosure is not deviated, various modifications that can be conceived by those skilled in the art are applied to the present embodiment, and a form constructed by combining components in different embodiments is also within the scope of one or more embodiments. May be included within.

The present disclosure can be applied to display devices such as liquid crystal televisions.

100 Display device 101 Display panel 102 Source driver 103 Gate driver 104, 104A Control unit 105 DA converter 111, 112, 113 Video signal 114 Input signal 115 Reference voltage 116 Data signal 121, 121A Switching unit 122 Curve conversion unit 123 Signal processing unit 124 Inverse gamma conversion unit 125 Brightness determination unit

Claims (4)

A display device that displays video based on video signals.
A display panel for displaying the above image and
It is provided with a control unit that changes the gamma characteristic of the display panel according to the luminance dynamic range of the video signal .
The control unit
It is determined whether the luminance dynamic range of the video signal is the first luminance dynamic range or the second luminance dynamic range wider than the first luminance dynamic range.
When the luminance dynamic range of the video signal is the first luminance dynamic range, the gamma value indicating the gamma characteristic of the display panel is set to the first gamma value, and the luminance dynamic range of the video signal is the second luminance. A display device that sets the gamma value to a second gamma value larger than the first gamma value in the case of a dynamic range . The display device further
A DA converter that generates the reference voltage used for gamma conversion,
A source driver that generates a data signal by gamma-converting an input signal based on the video signal using the reference voltage and supplies the generated data signal to the display panel is provided.
The display device according to claim 1, wherein the control unit changes the gamma characteristic of the display panel by changing the reference voltage generated by the DA converter. The control unit
The display device according to claim 2, wherein when the average brightness of the video signal is less than a predetermined reference value, the reference voltage for low gradation generated by the DA converter is increased. It is a control method of a display device provided with a display panel for displaying an image based on an image signal and displaying the image.
The gamma characteristic of the display panel is changed according to the luminance dynamic range of the video signal .
It is determined whether the luminance dynamic range of the video signal is the first luminance dynamic range or the second luminance dynamic range wider than the first luminance dynamic range.
When the luminance dynamic range of the video signal is the first luminance dynamic range, the gamma value indicating the gamma characteristic of the display panel is set to the first gamma value, and the luminance dynamic range of the video signal is the second luminance. A method of controlling a display device in which the gamma value is set to a second gamma value larger than the first gamma value in the case of a dynamic range .

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