Display device

Abstract

A display device is disclosed. The display device of the present invention includes: a pixel portion including a pixel; a compensation portion generating compensation image data by scaling a gradation value of input image data based on temperature data corresponding to an ambient temperature of the pixel portion; a timing control portion generating image data based on the compensation image data; and a data drive portion generating a data signal corresponding to the image data and supplying to the pixel. In a case where the ambient temperature is greater than a reference temperature, the compensation portion scales the gradation value in such a manner that the gradation value of the input image data is decreased. In a case where the ambient temperature is less than the reference temperature, the compensation portion scales the gradation value in such a manner that the gradation value of the input image data is increased.

Description

Technical Field

[0001] This invention relates to a display device. Background Technology

[0002] The display device may include a display panel for displaying images. The display panel may include pixels, and the light-emitting elements included in each pixel may emit light with a brightness corresponding to the amount of driving current.

[0003] However, the current flowing through the display panel varies depending on the ambient temperature, and the display panel may emit light at a brightness different from the target brightness. Therefore, it is necessary to control the display to show an image at the target brightness regardless of the ambient temperature of the display panel. Summary of the Invention

[0004] One object of the present invention is to provide a display device capable of displaying an image of target brightness regardless of ambient temperature.

[0005] A display device according to an embodiment of the present invention may include: a pixel unit comprising pixels; a compensation unit that generates compensated image data by scaling the grayscale value of input image data based on temperature data corresponding to the ambient temperature of the pixel unit; a timing control unit that generates image data based on the compensated image data; and a data driving unit that generates a data signal corresponding to the image data and supplies it to the pixels. When the ambient temperature is greater than a reference temperature, the compensation unit may scale the grayscale value to decrease the grayscale value of the input image data. When the ambient temperature is less than the reference temperature, the compensation unit may scale the grayscale value to increase the grayscale value of the input image data.

[0006] In one embodiment, the display device may further include: a power supply unit that generates a reference voltage using an input voltage. The data driving unit may use the reference voltage to generate the data signal, and the compensation unit may generate a power control signal for controlling the voltage level of the reference voltage based on the temperature data.

[0007] In one embodiment, the compensation unit may include: a grayscale extraction unit that extracts representative grayscale values ​​based on the input image data; a compensation signal generation unit that generates a first compensation control signal and a second compensation control signal as the power control signal based on the temperature data and the representative grayscale values; and a compensation data generation unit that generates the compensation image data based on the input image data and the first compensation control signal.

[0008] In one embodiment, the representative grayscale value may correspond to the largest grayscale value among the grayscale values ​​of the input image data.

[0009] In one embodiment, the compensation signal generation unit may include: a first scaling factor generation unit that generates a first scaling factor corresponding to the ambient temperature based on the temperature data; a calculation unit that calculates a first corrected gray value based on the first scaling factor and the representative gray value; a comparison unit that compares the first corrected gray value with a reference gray value and generates comparison result data; and a second scaling factor generation unit that generates a second scaling factor corresponding to the first compensation control signal based on the comparison result data.

[0010] In one embodiment, when the ambient temperature is lower than the reference temperature, the first scaling factor generating unit can generate a first scaling factor with a value greater than 1. The lower the ambient temperature, the larger the value of the first scaling factor can be.

[0011] In one embodiment, when the ambient temperature is greater than the reference temperature, the first scaling factor generating unit can generate a first scaling factor with a value less than 1. The higher the ambient temperature, the smaller the value of the first scaling factor.

[0012] In one embodiment, when the ambient temperature is the same as the reference temperature, the first scaling factor generation unit can generate a first scaling factor with a value of 1.

[0013] In one embodiment, the calculation unit can calculate the first corrected gray value by multiplying the representative gray value by the first scaling factor.

[0014] In one embodiment, the comparison unit may calculate a second corrected gray value based on the comparison result between the first corrected gray value and the reference gray value.

[0015] In one embodiment, when the first corrected grayscale value is below the reference grayscale value, the comparison unit can calculate a second corrected grayscale value that is the same as the first corrected grayscale value; when the first corrected grayscale value is greater than the reference grayscale value, the comparison unit can calculate a second corrected grayscale value that is the same as the reference grayscale value.

[0016] In one embodiment, the compensation signal generation unit may further include a power control signal generation unit, which generates a power control signal corresponding to the second compensation control signal based on the comparison result data.

[0017] In one embodiment, when the first corrected gray value and the second corrected gray value are not the same, the second scaling factor generation unit can generate a second scaling factor with a value smaller than the first scaling factor.

[0018] In one embodiment, the value of the second scaling factor applied to the representative grayscale value can correspond to the reference grayscale value.

[0019] In one embodiment, the power supply unit may generate a reference voltage having a voltage level different from the input voltage based on the power control signal.

[0020] In one embodiment, when the first corrected gray value and the second corrected gray value are the same, the second scaling factor generation unit can generate a second scaling factor having the same value as the first scaling factor.

[0021] In one embodiment, the power supply unit may generate a reference voltage having the same voltage level as the input voltage based on the power control signal.

[0022] A display device according to an embodiment of the present invention may include: a pixel unit comprising pixels; a compensation unit that calculates a target current value corresponding to input image data and generates compensated image data by scaling the grayscale value of the input image data based on the target current value and a global current value flowing through the pixels; a timing control unit that generates image data based on the compensated image data; and a data driving unit that generates a data signal corresponding to the image data and supplies it to the pixels. When the global current value is greater than the target current value, the compensation unit may scale the grayscale value to decrease the grayscale value of the input image data. When the global current value is less than the target current value, the compensation unit may scale the grayscale value to increase the grayscale value of the input image data.

[0023] In one embodiment, the display device may further include: a power supply unit that generates a reference voltage using an input voltage. The data driving unit may generate the data signal using the reference voltage, and the compensation unit may also generate a power control signal for controlling the voltage level of the reference voltage based on the target current value and the global current value.

[0024] In one embodiment, the pixel may be connected to a power line. The display device may further include a current sensor that generates the global current value by sensing the current flowing through the power line.

[0025] The display device according to an embodiment of the present invention can scale the grayscale value of the input image data in accordance with the ambient temperature of the display panel and control the voltage level of the reference voltage. Accordingly, an image with a target brightness can be displayed on the display panel regardless of the ambient temperature.

[0026] Furthermore, the display device according to an embodiment of the present invention can sense the current flowing through the display panel, scale the grayscale value of the input image data accordingly to the sensed current value, and control the voltage level of the reference voltage. Accordingly, an image with a target brightness can be displayed on the display panel regardless of the ambient temperature.

[0027] However, the effects of the present invention are not limited to those described above, and can be extended in various ways without departing from the spirit and scope of the present invention. Attached Figure Description

[0028] Figure 1 This is a block diagram illustrating a display device according to an embodiment of the present invention.

[0029] Figure 2 It is a graph used to illustrate how the current flowing through the display panel changes with temperature.

[0030] Figure 3 It is shown that includes Figure 1 A circuit diagram of an example of the pixels of a display device.

[0031] Figure 4 It is shown that includes Figure 1 A block diagram of an example of the data driving section of a display device.

[0032] Figure 5 It is shown that includes Figure 1 A block diagram of an example of the compensation section of a display device.

[0033] Figure 6 It is shown that includes Figure 5 A block diagram of an example of the compensation signal generation unit of the compensation section.

[0034] Figure 7a and Figure 7b It is used for explanation Figure 5 A diagram illustrating an example of the operation of the compensation unit.

[0035] Figure 8 This is a block diagram illustrating a display device according to an embodiment of the present invention.

[0036] Figure 9 It is shown that includes Figure 8 A block diagram of an example of the compensation section of a display device. Detailed Implementation

[0037] This invention can be modified in various ways and can take many forms. Specific embodiments will be shown in the accompanying drawings and described in detail herein. However, this is not intended to limit the invention to the specific disclosed forms, and it should be understood to include all modifications, equivalents, and substitutions contained within the spirit and scope of this invention.

[0038] Similar reference numerals are used for similar constituent elements in the description of the various figures. In the figures, for clarity of the invention, the dimensions of the structures are shown enlarged compared to their actual dimensions. While terms such as "first," "second," etc., may be used to describe various constituent elements, the constituent elements should not be limited to those terms. These terms are used only to distinguish one constituent element from another. For example, a first constituent element may be named a second constituent element without departing from the scope of the invention, and similarly, a second constituent element may be named a first constituent element. Unless the context clearly indicates a different meaning, singular expressions include plural expressions.

[0039] In this application, terms such as “comprising” or “having” specify the presence of features, figures, steps, operations, constituent elements, parts, or combinations thereof described in the specification, and should be understood as not precluding the possibility of the presence or addition of one or more other features or figures, operations, constituent elements, parts, or combinations thereof.

[0040] Furthermore, when it is described as a part being "connected" to another part, this includes not only the case of a direct connection, but also the case of a connection with other elements in between.

[0041] Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

[0042] Figure 1 This is a block diagram illustrating a display device according to an embodiment of the present invention. Figure 2 It is a graph used to illustrate how the current flowing through the display panel changes with temperature.

[0043] Reference Figure 1 The display device 1000 may include a display panel 100, a timing control unit 200, a compensation unit 300, a scan driving unit 400, a data driving unit 500, and a power supply unit 600. According to an embodiment, the display device 1000 may also include a temperature sensor TS. The temperature sensor TS can sense the ambient temperature of the display device 1000 (or the display panel 100) to generate temperature data TD.

[0044] The display panel 100 (or pixel unit) may include pixels. Each pixel PXij can be connected to a corresponding data line and scan line. i and j can be integers greater than 0. Pixel PXij may refer to the pixel connected to the scan transistor and the i-th scan line and the j-th data line.

[0045] Each pixel PXij can be connected to a first power line VDDL and a second power line VSSL. Pixel PXij can receive the voltage of the first power supply VDD through the first power line VDDL and the voltage of the second power supply VSS through the second power line VSSL. Here, the voltages of the first power supply VDD and the second power supply VSS can be the voltages required for the operation of the pixel. The first power supply VDD can have a higher voltage level than the second power supply VSS. For example, the voltage of the first power supply VDD can be a positive voltage, and the voltage of the second power supply VSS can be a negative voltage.

[0046] The timing control unit 200 can receive a control signal CS from an external source. Here, the control signal CS may include a synchronization signal, a clock signal, etc.

[0047] The timing control unit 200 can generate a first control signal SCS (or a scan control signal) and a second control signal DCS (or a data control signal) based on the control signal CS. The timing control unit 200 can supply the first control signal SCS to the scan drive unit 400 and the second control signal DCS to the data drive unit 500.

[0048] The first control signal SCS may include a scan start signal, a clock signal, etc. The scan start signal may be a signal used to control the timing of the scan signals. The clock signal included in the first control signal SCS may be used to shift the scan start signal.

[0049] The second control signal DCS may include a clock signal supplied to the register section of the data drive unit 500, a line latch signal supplied to the latch section, etc.

[0050] The compensation unit 300 can receive input image data IDATA from an external source. Here, the input image data IDATA may include at least one image frame.

[0051] In one embodiment, the compensation unit 300 can receive temperature data TD from the temperature sensor TS. The compensation unit 300 can generate a scaling factor corresponding to the ambient temperature of the display panel 100 (or display device 1000) based on the temperature data TD.

[0052] For example, such as Figure 2As shown, when the ambient temperature of the display panel 100 increases to or above the reference temperature (e.g., room temperature), the current flowing through the pixel PXij (or the display panel 100) can increase to or above the target current. Accordingly, the brightness of the image displayed by the display panel 100 can increase to or above the target brightness. In this case, the compensation unit 300 can generate a scaling factor for controlling the flow of a target current corresponding to the target brightness of the displayed image through the pixel PXij. Here, the scaling factor can be less than 1.

[0053] As another example, such as Figure 2 As shown, when the ambient temperature of the display panel 100 decreases below the reference temperature, the current flowing through the pixel PXij (or the display panel 100) can be reduced to below the target current. Accordingly, the brightness of the image displayed by the display panel 100 can be reduced to below the target brightness. In this case, the compensation unit 300 can generate a scaling factor for controlling the flow of a target current corresponding to the target brightness of the displayed image through the pixel PXij. Here, the scaling factor can be greater than 1.

[0054] The compensation unit 300 can generate compensated image data CDATA by scaling the grayscale values ​​of the input image data IDATA using a scaling factor. The compensated image data CDATA can be provided to the timing control unit 200. The brightness of the image displayed on the display panel 100 can be controlled based on the compensated image data CDATA generated by scaling the grayscale values ​​of the input image data IDATA.

[0055] Furthermore, when the ambient temperature of the display panel 100 is the same as the reference temperature, the compensation unit 300 can scale the grayscale value of the input image data IDATA by generating a scaling factor with a value of 1. However, the present invention is not limited to this. When the ambient temperature of the display panel 100 is the same as the reference temperature, the compensation unit 300 can also provide the input image data IDATA as compensated image data CDATA to the timing control unit 200 without needing to scale the grayscale value of the input image data IDATA separately.

[0056] The timing control unit 200 rearranges the compensated image data CDATA generated by scaling the grayscale values ​​of the input image data IDATA to generate digital image data DATA, and can provide the digital image data DATA to the data driving unit 500.

[0057] The scan drive unit 400 can receive a first control signal SCS from the timing control unit 200 and supply scan signals to scan lines SL1 to SLn in response to the first control signal SCS. n can be an integer greater than 0. For example, the scan drive unit 400 can supply scan signals to scan lines SL1 to SLn sequentially. When supplying scan signals sequentially, pixels PXij can be selected in horizontal line units (or pixel row units), and data signals can be supplied to the selected pixels PXij. For this purpose, the scan signal can be set to a gate on-state voltage (low voltage or high voltage) so that the transistors (e.g., scan transistors) included in each pixel PXij and receiving the scan signal are turned on.

[0058] The data driving unit 500 can receive image data DATA and a second control signal DCS from the timing control unit 200, and in response to the second control signal DCS, convert the digital image data DATA into an analog data signal (data voltage) and supply it to data lines DL1 to DLm. m can be an integer greater than 0. The data signals supplied to data lines DL1 to DLm can be supplied to the pixel PXij selected by the scan signal. Therefore, the data driving unit 500 can supply data signals to data lines DL1 to DLm synchronously with the scan signal.

[0059] At this time, since the image data DATA is generated based on the compensated image data CDATA generated by scaling the gray values ​​of the input image data IDATA using a scaling factor, the data driving unit 500 can supply the data signal corresponding to the scaled gray value to the data lines DL1 to DLm. For example, the data driving unit 500 can apply the data signal corresponding to the gray value of the scaled pixel PXij to the j-th data line.

[0060] The power supply unit 600 can receive an input voltage VIN from an external source (e.g., a battery) and can generate a reference voltage VGM based on the input voltage VIN. The reference voltage VGM can be supplied to the data drive unit 500. The data drive unit 500 can receive the reference voltage VGM as input, convert the digital image data DATA into an analog signal (i.e., grayscale voltage), and supply it as a data signal (data voltage) to the pixel PXij.

[0061] The data driving unit 500 can use a reference voltage VGM to generate multiple gamma voltages representing a predetermined grayscale. For example, the data driving unit 500 can generate multiple gamma voltages between the ground voltage and the reference voltage VGM by dividing the reference voltage VGM. The data driving unit 500 can provide the value of the multiple gamma voltages corresponding to the image data DATA as a data signal (data voltage) to the pixel PXij.

[0062] Furthermore, since grayscale values ​​have values ​​greater than 0 and less than 255, the value obtained by applying a scaling factor to the representative grayscale value corresponding to the maximum grayscale value in the input image data IDATA (or the expected corrected grayscale value) cannot be greater than the reference grayscale value (e.g., 255 corresponding to the maximum grayscale value). Accordingly, the value of the scaling factor generated by the compensation unit 300 can be limited based on the grayscale values ​​(e.g., the representative grayscale value) of the input image data IDATA and the ambient temperature.

[0063] Accordingly, when the expected corrected grayscale value is greater than the reference grayscale value, the compensation unit 300 according to an embodiment of the present invention can generate a scaling factor in such a way that the final corrected grayscale value is below the reference grayscale value (e.g., the final corrected grayscale value is the same as the reference grayscale value), and can additionally generate a power control signal PCS for controlling the voltage level of the reference voltage VGM generated by the power supply unit 600. For example, the compensation unit 300 can generate a power control signal PCS for changing (increasing) the voltage level of the reference voltage VGM.

[0064] The power supply unit 600 can provide a reference voltage VGM with a modified voltage level to the data drive unit 500 based on the power control signal PCS. Since the multiple gamma voltages generated by the data drive unit 500 are generated by dividing the reference voltage, the value of the gamma voltage can also increase when the reference voltage VGM increases. Accordingly, the voltage level of the data signal (data voltage) generated by the data drive unit 500 can increase relative to the same grayscale value.

[0065] Thus, according to an embodiment of the present invention, the compensation unit 300 can scale the grayscale value of the input image data IDATA in accordance with the ambient temperature, and control the voltage level of the reference voltage VGM provided to the data driving unit 500 based on the ambient temperature and the grayscale value, thereby controlling the brightness of the displayed image. Accordingly, the display panel 100 can display an image with a target brightness regardless of the ambient temperature.

[0066] Figure 3 It is shown that includes Figure 1 A circuit diagram of an example of the pixels of a display device.

[0067] refer to Figure 3 The pixel PXij may include a light-emitting element LD and a driving circuit DC connected to the light-emitting element LD to drive the light-emitting element LD.

[0068] The first electrode (e.g., the anode electrode) of the light-emitting element (LD) can be connected to the first power supply line VDDL via the driving circuit DC, and the second electrode (e.g., the cathode electrode) of the light-emitting element (LD) can be connected to the second power supply line VSSL. The light-emitting element (LD) can emit light with a brightness corresponding to the amount of driving current controlled by the driving circuit DC.

[0069] Organic light-emitting diodes (OLEDs) can be chosen as the light-emitting element (LD). Furthermore, inorganic light-emitting diodes (LEDs), such as micro LEDs and quantum dot LEDs, can also be chosen as the LD. Additionally, the LD can be a composite element made of organic and inorganic materials. Although... Figure 3 The illustration shows a pixel PXij comprising a single light-emitting element LD, but in another embodiment, pixel PXij may comprise multiple light-emitting elements, and the multiple light-emitting elements may be connected in series, in parallel, or in a series-parallel connection.

[0070] The first power supply VDD, supplied to the first power line VDDL, and the second power supply VSS, supplied to the second power line VSSL, can have different potentials than each other. For example, the voltage of the first power supply VDD can be greater than the voltage of the second power supply VSS.

[0071] The driving circuit DC may include a first transistor T1, a second transistor T2, and a storage capacitor Cst.

[0072] The first electrode of the first transistor T1 (driving transistor) can be connected to the first power supply line VDDL, and the second electrode can be electrically connected to the first electrode (e.g., the anode electrode) of the light-emitting element LD. The gate electrode of the first transistor T1 can be connected to the first node N1. The first transistor T1 can control the amount of driving current supplied to the light-emitting element LD in response to the data signal supplied to the first node N1 via the data line DLj.

[0073] The first electrode of the second transistor T2 (switching transistor) can be connected to the data line DLj, and the second electrode can be connected to the first node N1. The gate electrode of the second transistor T2 can be connected to the scan line SLi.

[0074] When a scan signal, capable of turning on the second transistor T2 (e.g., gate on-state voltage), is supplied from the scan line SL1, the second transistor T2 turns on to electrically connect the data line DLj to the first node N1. At this time, a data signal corresponding to the frame is provided to the data line DLj, thereby allowing the data signal to be transmitted to the first node N1. The voltage corresponding to the data signal transmitted to the first node N1 can be stored in the storage capacitor Cst.

[0075] One electrode of the storage capacitor Cst can be connected to the first node N1, and the other electrode of the storage capacitor Cst can be connected to the first electrode of the light-emitting element LD. Such a storage capacitor Cst can be charged with a voltage corresponding to the data signal supplied to the first node N1, and the charged voltage can be maintained until the data signal of the next frame is supplied.

[0076] In addition, for ease of explanation, Figure 3 The pixel PXij is shown in a relatively simple form, and the structure of the driving circuit DC can be implemented in various ways. As an example, the driving circuit DC can also be supplemented with various transistors, such as a compensation transistor for compensating the threshold voltage of the first transistor T1, an initialization transistor for initializing the first node N1, and / or a light emission control transistor for controlling the light emission time of the light-emitting element LD, or other circuit elements such as a boost capacitor for boosting the voltage of the first node N1.

[0077] And, although Figure 3 The illustration shows a scenario where the transistors (e.g., the first transistor T1 and the second transistor T2) included in the drive circuit DC are both N-type transistors, but the invention is not limited thereto. That is, at least one of the first transistor T1 and the second transistor T2 included in the drive circuit DC can be changed to a P-type transistor.

[0078] Figure 4 It is shown that includes Figure 1 A block diagram of an example of the data driving section of a display device.

[0079] Reference Figure 1 and Figure 4 The data drive unit 500 may include a register unit 510, a latch unit 520, a digital-to-analog converter 530, and a buffer unit 540.

[0080] The register section 510 can be synchronized with the clock signal CLK to sequentially activate the latch clock signal and provide it to the latch section 520. The register section 510 may include multiple shift registers.

[0081] The latch unit 520 can receive latch clock signals sequentially provided by the register unit 510, and sample and latch the digital image data DATA in sync with the latch clock signal. Furthermore, the latch unit 520 can provide the latched digital image data DATA to the digital-to-analog converter 530 in response to the latch signal.

[0082] The digital-to-analog converter 530 can convert digital image data DATA provided by the latch unit 520 into an analog signal. The digital-to-analog converter 530 can receive a reference voltage VGM input from the power supply unit 600, convert the digital image data DATA into an analog signal (i.e., grayscale voltage), and provide the converted analog signal as a data signal (data voltage) to the buffer unit 540.

[0083] According to an embodiment, the digital-to-analog converter 530 may include a voltage generation unit 531 and a decoding unit 532.

[0084] The voltage generation unit 531 can generate multiple gamma voltages representing a predetermined grayscale using a reference voltage VGM supplied from the power supply unit 600. For example, the voltage generation unit 531 can generate gamma voltages by dividing the reference voltage VGM using multiple resistors connected in series between the reference voltage VGM and the ground voltage. As an example, when the image data DATA is 10 bits, the voltage generation unit 531 can generate 2... 10 One (i.e., 1024) gamma voltages V0 to V1023.

[0085] Additionally, as referenced Figure 1 As described above, when the voltage level of the reference voltage VGM supplied from the power supply unit 600 changes, the voltage level of the gamma voltages V0 to V1023 generated by the voltage generation unit 531 can also change accordingly.

[0086] The decoding unit 532 can receive gamma voltages V0 to V1023 from the voltage generation unit 531, and output the corresponding gamma voltages from V0 to V1023 as data signals (data voltages) to the buffer unit 540 according to the input image data DATA.

[0087] The buffer unit 540 can output the data signal from the digital-to-analog converter 530 to the corresponding data lines DL1 to DLm.

[0088] Figure 5 It is shown that includes Figure 1 A block diagram of an example of the compensation section of a display device. Figure 6 It is shown that includes Figure 5 A block diagram of an example of the compensation signal generation unit of the compensation section. Figure 7a and Figure 7b It is used for explanation Figure 5 A diagram illustrating an example of the operation of the compensation unit.

[0089] Reference Figure 1 and Figure 5 The compensation unit 300 may include a grayscale extraction unit 310, a compensation signal generation unit 320, and a compensation data generation unit 330.

[0090] The grayscale extraction unit 310 can extract a representative grayscale value RGS based on the input image data IDATA. Here, the representative grayscale value RGS can correspond to the largest grayscale value among the grayscale values ​​of the input image data IDATA.

[0091] The compensation signal generation unit 320 can generate a first compensation control signal CPS1 and a second compensation control signal CPS2 based on temperature data TD. Here, the first compensation control signal CPS1 can be a reference signal. Figure 1 The scaling factor explained, the second compensation control signal CPS2 can be a reference. Figure 1 The power control signal PCS is described.

[0092] The compensation data generation unit 330 can receive the first compensation control signal CPS1 from the compensation signal generation unit 320, and can generate compensation image data CDATA by scaling the grayscale value of the input image data IDATA based on the first compensation control signal CPS1.

[0093] To further explain the compensation signal generation unit 320, please refer to... Figure 6 The compensation signal generation unit 320 may include a first scaling factor generation unit 321, a calculation unit 322, a comparison unit 323, a second scaling factor generation unit 324, and a power control signal generation unit 325.

[0094] The first scaling factor generation unit 321 can generate a first scaling factor SF1 corresponding to the ambient temperature of the display panel 100 based on the temperature data TD.

[0095] In one embodiment, when the ambient temperature is higher than a reference temperature (e.g., room temperature), the first scaling factor generation unit 321 can generate a first scaling factor SF1 with a value less than 1. Here, the higher the ambient temperature, the smaller the value of the first scaling factor SF1 generated by the first scaling factor generation unit 321 can have.

[0096] Furthermore, when the ambient temperature is lower than the reference temperature, the first scaling factor generation unit 321 can generate a first scaling factor SF1 with a value greater than 1. Here, the lower the ambient temperature, the larger the value of the first scaling factor SF1 generated by the first scaling factor generation unit 321 can have.

[0097] Furthermore, when the ambient temperature is the same as the reference temperature, the first scaling factor generation unit 321 can generate a first scaling factor SF1 with a value of 1.

[0098] According to an embodiment, the first scaling factor generation unit 321 can generate a first scaling factor SF1 based on a pre-stored lookup table (LUT). The lookup table LUT may include a value of the first scaling factor SF1 preset according to the ambient temperature. For example, the first scaling factor SF1 can be experimentally determined based on the ambient temperature.

[0099] However, this is merely exemplary, and the present invention is not limited thereto. For example, the first scaling factor generation unit 321 can generate a first scaling factor SF1 based on the ambient temperature using a pre-set calculation formula or the like.

[0100] The calculation unit 322 can receive a first scaling factor SF1 from the first scaling factor generation unit 321 and receive a representative gray value RGS from the gray value extraction unit 310.

[0101] The calculation unit 322 can calculate the expected corrected gray value CGS1 (or the first corrected gray value) based on the representative gray value RGS and the first scaling factor SF1. For example, the calculation unit 322 can calculate the expected corrected gray value CGS1 by multiplying the representative gray value RGS by the first scaling factor SF1.

[0102] The comparison unit 323 can compare the expected corrected grayscale value CGS1 with the reference grayscale value FGS. Here, the reference grayscale value FGS can correspond to the maximum grayscale value (e.g., 255) among grayscale values ​​(e.g., values ​​above 0 and below 255).

[0103] The comparison unit 323 can calculate the final corrected grayscale value CGS2 (or, the second corrected grayscale value) based on the comparison result between the expected corrected grayscale value CGS1 and the reference grayscale value FGS. For example, if the expected corrected grayscale value CGS1 is less than or equal to the reference grayscale value FGS, the comparison unit 323 can calculate the same final corrected grayscale value CGS2 as the expected corrected grayscale value CGS1. As another example, if the expected corrected grayscale value CGS1 is greater than the reference grayscale value FGS, the comparison unit 323 can calculate the same final corrected grayscale value CGS2 as the reference grayscale value FGS.

[0104] The comparison unit 323 can generate comparison result data CRD based on the comparison results described above, and provide it to the second scaling factor generation unit 324 and the power control signal generation unit 325. Here, the comparison result data CRD may include the expected correction grayscale value CGS1 and the final correction grayscale value CGS2.

[0105] Based on the comparison result data CRD, the second scaling factor generation unit 324 can generate a second scaling factor SF2 (or a first compensation control signal CPS1), and the power control signal generation unit 325 can generate a power control signal PCS (or a second compensation control signal CPS2).

[0106] For example, when the expected corrected grayscale value CGS1 and the final corrected grayscale value CGS2 are the same, the second scaling factor generation unit 324 can generate the first scaling factor SF1 provided by the first scaling factor generation unit 321 as the second scaling factor SF2. That is, the second scaling factor SF2 can be the same as the first scaling factor SF1. Since the expected corrected grayscale value CGS1 is a value generated based on the first scaling factor SF1, when the expected corrected grayscale value CGS1 and the final corrected grayscale value CGS2 are the same, even if the grayscale value of the input image data IDATA is scaled using the same value as the first scaling factor SF1, the scaled grayscale value will not be greater than the reference grayscale value FGS (i.e., 255, which is the maximum grayscale value). Accordingly, the second scaling factor generation unit 324 can generate a second scaling factor SF2 with the same value as the first scaling factor SF1.

[0107] In this case, the power control signal generation unit 325 can generate a power control signal PCS for controlling the voltage level of the reference voltage VGM to remain unchanged. At this time, the power supply unit 600 can generate a reference voltage VGM having the same voltage level as the input voltage VIN based on the power control signal PCS. However, the present invention is not limited to this; the power control signal generation unit 325 may also choose not to generate an additional power control signal PCS.

[0108] As another example, when the expected corrected grayscale value CGS1 and the final corrected grayscale value CGS2 are not the same, the second scaling factor generation unit 324 can generate a second scaling factor SF2 that is smaller than the value of the first scaling factor SF1 provided by the first scaling factor generation unit 321. When the expected corrected grayscale value CGS1 and the final corrected grayscale value CGS2 are not the same, this corresponds to the situation where the expected corrected grayscale value CGS1, corresponding to the value of multiplying the representative grayscale value RGS by the first scaling factor SF1, is greater than the reference grayscale value FGS (i.e., the maximum grayscale value 255). Accordingly, the second scaling factor generation unit 324 can generate the second scaling factor SF2 in a manner that makes the value of the scaled input image data IDATA equal to or less than the reference grayscale value FGS. For example, the second scaling factor generation unit 324 can generate the second scaling factor SF2 in a manner that makes the scaled representative grayscale value RGS the same as the reference grayscale value FGS. For example, the second scaling factor generation unit 324 can generate the second scaling factor SF2 according to the following mathematical formula 1.

[0109]

Mathematical Formula 1

[0110]

[0111] Wherein, SF1 and SF2 represent the first scaling factor SF1 and the second scaling factor SF2, respectively, and CGS1 and CGS2 represent the expected corrected grayscale value CGS1 and the final corrected grayscale value CGS2, respectively.

[0112] In this case, the power control signal generation unit 325 can generate a power control signal PCS for changing (e.g., increasing) the voltage level of the reference voltage VGM. For example, the power control signal generation unit 325 can generate a power control signal PCS for increasing the voltage level of the reference voltage VGM by a ratio equivalent to the reduction of the second scaling factor SF2 relative to the first scaling factor SF1. Based on such a power control signal PCS, the power supply unit 600 can amplify the voltage level of the input voltage VIN to generate the reference voltage VGM. The reference voltage VGM generated based on the power control signal PCS is shown in the following mathematical formula 2.

[0113]

Mathematical Formula 2

[0114]

[0115] Where VGM represents the reference voltage VGM, VIN represents the input voltage VIN, and CGS1 and CGS2 represent the expected correction grayscale value CGS1 and the final correction grayscale value CGS2, respectively.

[0116] Thus, according to an embodiment of the present invention, the compensation unit 300 can control the brightness of the displayed image by scaling the grayscale value of the input image data IDATA according to the ambient temperature. Furthermore, the compensation unit 300 can control the grayscale value scaled according to the ambient temperature and grayscale value to be no greater than the reference grayscale value FGS, and control (change) the voltage level of the reference voltage VGM supplied to the data driving unit 500, thereby further controlling the brightness of the displayed image. Accordingly, the display panel 100 can display an image with a target brightness independent of the ambient temperature.

[0117] Furthermore, the above explanation is based on the case where the reference grayscale value FGS is 255, which is the maximum grayscale value. In this case, the second scaling factor generation unit 324 can make the scaled grayscale value include the grayscale region below 255, which is the maximum grayscale value. Figure 7a The second scaling factor SF2 is generated in the manner shown in the first grayscale region GSA1.

[0118] However, the present invention is not limited thereto. Based on the voltage level of the reference voltage VGM and the data voltage Vdata corresponding to the gray value, the second scaling factor generation unit 324 may also generate the second scaling factor SF2 in a manner that scales the gray value to a virtual gray area of ​​255 or more.

[0119] Specifically, further reference Figure 7b According to the present invention, the display device 1000 (or the compensation unit 300) can generate a second grayscale region GSA2 (or a virtual grayscale region) greater than 255. Here, the second grayscale region GSA2 may correspond to a region that does not include the grayscale values ​​of the input image data IDATA received from the outside, but may include grayscale values ​​scaled by a second scaling factor SF2.

[0120] For example, the value of the virtual grayscale data voltage Vdata in the second grayscale region GSA2 can increase linearly equivalent to the difference between the data voltage Vdata of grayscale 255 and grayscale 254, which are the maximum grayscale values. As an example, the value of the data voltage Vdata from virtual grayscale 256 to virtual grayscale 270 can increase linearly by 0.024V, which is the difference between the data voltage Vdata of grayscale 255 and grayscale 254.

[0121] At this point, the maximum virtual grayscale value of the second grayscale region GSA2 can be determined based on the voltage level of the reference voltage VGM. For example, because Figure 4The voltage generation unit 531 included in the data driving unit 500 generates a gamma voltage by dividing the reference voltage VGM. Therefore, it is necessary to set the value of the data voltage Vdata corresponding to the maximum virtual grayscale value of the second grayscale region GSA2 to a voltage level below the reference voltage VGM. As an example, when the voltage level of the reference voltage VGM is 8V, the maximum virtual grayscale value of the second grayscale region GSA2 can be set to a virtual grayscale value of 270 corresponding to the data voltage Vdata of 7.988V.

[0122] Thus, the display device 1000 according to an embodiment of the present invention can not only ensure the first grayscale region GSA1, but also additionally ensure a second grayscale region as a virtual grayscale region based on the voltage level of the reference voltage VGM supplied to the data driving unit 500. In this case, since the compensation unit 300 according to an embodiment of the present invention can set the reference grayscale value FGS to a value corresponding to the maximum virtual grayscale value of the second grayscale region GSA2 (e.g., 270) instead of grayscale 255, the range of the second scaling factor SF2 that the second scaling factor generation unit 324 can generate can be increased. Accordingly, even without separately generating a power control signal PCS for changing the voltage level of the reference voltage VGM according to the ambient temperature, the compensation signal generation unit 320 can use only the second scaling factor SF2 to make the range of controllable brightness of the displayed image wider.

[0123] Figure 8 This is a block diagram illustrating a display device according to an embodiment of the present invention. Figure 9 It is shown that includes Figure 8 A block diagram of an example of the compensation section of a display device. Additionally, Figure 8 The display device 1000' and Figure 9 The compensation section 300', apart from some of its constituent elements, is respectively related to... Figure 1 The display device 1000 and Figure 5 The compensation unit 300 is substantially the same or similar, so it will not be described repeatedly.

[0124] Reference Figure 8 The display device 1000' may include a display panel 100, a timing control unit 200, a compensation unit 300', a scan drive unit 400, a data drive unit 500, and a power supply unit 600.

[0125] According to an embodiment, the display device 1000' may further include a current sensor CS. The current sensor CS generates a global current value GC by sensing the current flowing through the display panel 100. Here, the value of the current flowing through the display panel 100 may vary depending on the ambient temperature of the display panel 100. As an example, when the ambient temperature of the display panel 100 increases above a reference temperature, the value of the current flowing through the display panel 100 may increase (i.e., the global current value GC increases). And, when the ambient temperature of the display panel 100 decreases below the reference temperature, the value of the current flowing through the display panel 100 may decrease (i.e., the global current value GC decreases).

[0126] In one embodiment, a current sensor CS can be connected to a first power line VDDL that is commonly connected to pixel PXij. The current sensor CS can sense the current flowing through the first power line VDDL to generate a global current value GC. Here, the global current value GC can correspond to the current commonly supplied to all pixels PXij through the first power line VDDL. However, the invention is not limited to this; for example, the current sensor CS can also be connected to a second power line VSSL that is commonly connected to all pixels PXij to sense the current flowing through the second power line VSSL.

[0127] The current sensor CS can provide the global current value GC to the compensation unit 300'.

[0128] In one embodiment, the compensation unit 300' may generate a scaling factor based on the global current value GC. For example, the compensation unit 300' may calculate a target current value corresponding to the input image data IDATA, and compare the target current value with the global current value GC to generate a scaling factor for controlling the current flowing through the display panel 100 to achieve the target current value (for example, referring to...). Figure 6 The second scaling factor (SF2) is explained.

[0129] For a more detailed explanation of the compensation section 300', please refer to... Figure 9 The compensation unit 300' may include a grayscale extraction unit 310, a compensation signal generation unit 320', a compensation data generation unit 330, and a target current calculation unit 340.

[0130] The target current calculation unit 340 can calculate the target current value TC based on the input image data IDATA. Here, the target current value TC can correspond to the current value flowing through the display panel 100 that should correspond to the grayscale value of the input image data IDATA. For example, the target current calculation unit 340 can calculate the target current value TC corresponding to the grayscale value of the input image data IDATA using a pre-stored lookup table or a pre-set calculation formula.

[0131] The compensation signal generation unit 320' can generate a first compensation control signal CPS1 and a second compensation control signal CPS2 based on the target current value TC and the global current value GC.

[0132] Here, in generating references Figure 6 When the first scaling factor SF1 is described, the compensation signal generation unit 320' can generate the first scaling factor SF1 by comparing the target current value TC and the global current value GC. For example, the compensation signal generation unit 320' can determine the ratio between the target current value TC and the global current value GC as the first scaling factor SF1.

[0133] As an example, when the ambient temperature of the display panel 100 is greater than the reference temperature, since the global current value GC is greater than the target current value TC, the compensation signal generation unit 320' can generate a first scaling factor SF1 with a value less than 1.

[0134] As another example, when the ambient temperature of the display panel 100 is lower than the reference temperature, since the global current value GC is lower than the target current value TC, the compensation signal generation unit 320' can generate a first scaling factor SF1 with a value greater than 1.

[0135] Thus, the display device 1000' according to an embodiment of the present invention can directly sense the global current value GC that varies according to the ambient temperature, and can generate a scaling factor based on the global current value GC. Accordingly, brightness compensation of the displayed image according to the ambient temperature can be performed more accurately.

[0136] The above detailed description illustrates and explains the present invention. Furthermore, the foregoing content is merely illustrative of preferred embodiments of the invention. As stated above, the invention can be used in a variety of other combinations, variations, and environments, and can be modified or altered within the scope of the inventive concept disclosed in this specification, within the equivalent scope of the foregoing disclosure, and / or within the scope of technology or knowledge in the art. Therefore, the above detailed description of the invention is not intended to limit the invention to the disclosed embodiments. Moreover, the appended claims should be interpreted as including other embodiments.

Claims

1. A display device, comprising: The pixel section contains pixels; The compensation unit generates compensated image data by scaling the grayscale value of the input image data based on temperature data corresponding to the ambient temperature of the pixel. The timing control unit generates image data based on the compensated image data; as well as The data driving unit generates a data signal corresponding to the image data and supplies it to the pixel. Specifically, when the ambient temperature is higher than the reference temperature, the compensation unit scales the grayscale value of the input image data in a manner that reduces the grayscale value of the input image data to generate compensated image data corresponding to a grayscale value smaller than the grayscale value of the input image data. When the ambient temperature is lower than the reference temperature, the compensation unit scales the gray value of the input image data in a manner that increases the gray value of the input image data to generate compensated image data corresponding to a gray value that is larger than the gray value of the input image data.

2. The display device according to claim 1, further comprising: The power supply section uses the input voltage to generate a reference voltage. The data driving unit uses the reference voltage to generate the data signal. The compensation unit also generates a power control signal based on the temperature data to control the voltage level of the reference voltage.

3. The display device according to claim 2, wherein, The compensation unit includes: The grayscale extraction unit extracts representative grayscale values ​​based on the input image data; The compensation signal generation unit generates a first compensation control signal and a second compensation control signal as the power control signal based on the temperature data and the representative grayscale value; and The compensation data generation unit generates the compensation image data based on the input image data and the first compensation control signal.

4. The display device according to claim 3, wherein, The grayscale value represents the largest grayscale value among the grayscale values ​​in the input image data.

5. The display device according to claim 3, wherein, The compensation signal generation unit includes: The first scaling factor generation unit generates a first scaling factor corresponding to the ambient temperature based on the temperature data. The calculation unit calculates a first corrected gray value based on the first scaling factor and the representative gray value; The comparison unit compares the first corrected grayscale value with the reference grayscale value and generates comparison result data; and The second scaling factor generation unit generates a second scaling factor corresponding to the first compensation control signal based on the comparison result data.

6. The display device according to claim 5, wherein, When the ambient temperature is lower than the reference temperature, the first scaling factor generation unit generates a first scaling factor with a value greater than 1. The lower the ambient temperature, the larger the value of the first scaling factor.

7. The display device according to claim 5, wherein, When the ambient temperature is greater than the reference temperature, the first scaling factor generation unit generates a first scaling factor with a value less than 1. The higher the ambient temperature, the smaller the value of the first scaling factor.

8. The display device according to claim 5, wherein, When the ambient temperature is the same as the reference temperature, the first scaling factor generation unit generates a first scaling factor with a value of 1.

9. The display device according to claim 5, wherein, The calculation unit calculates the first corrected gray value by multiplying the representative gray value by the first scaling factor.

10. The display device according to claim 5, wherein, If the first corrected grayscale value is lower than the reference grayscale value, the comparison unit generates the first corrected grayscale value as the comparison result data. If the first corrected grayscale value is greater than the reference grayscale value, the comparison unit generates the reference grayscale value as the comparison result data.

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