KR20110058352A - Organic light emitting display device - Google Patents

Abstract

PURPOSE: An organic light emitting display device is provided to improve color sense and display quality by preventing the change of a color coordinate system and color temperature according to luminance variation. CONSTITUTION: In an organic light emitting display device, a gamma part(60) sets a gamma reference voltage. The gamma part generates a gradation voltage value and outputs it. A data driver(DDRV) maps the gamma gradation voltage to a data signal. The data driver supplies the mapped gamma gradation voltage and the data signal to a display panel(PNL).

Description

Organic Light Emitting Display Device

The present invention relates to an organic light emitting display device.

The organic light emitting display device used in the organic light emitting display device is a self-light emitting device having a light emitting layer formed between two electrodes positioned on a substrate. The organic light emitting display includes a top emission type, a bottom emission type, or a dual emission type according to a direction in which light is emitted. In addition, depending on the driving method, it is divided into a passive matrix type and an active matrix type.

In the panel of the organic light emitting display device, the color temperature according to the color coordinate of white is set by the luminance ratio of red, green, and blue (RGB). The color temperature is used as a numerical value indicating how close to which color white appears.

In the conventional organic light emitting display device, the color coordinates change when the peak luminance of white displayed on the panel is changed. This is because the conventional organic light emitting display device uses the luminance ratio data of red, green, and blue in a memory or the like, in addition to the white peak luminance. Accordingly, when the user changes the white peak luminance in an application such as a mobile phone, a change occurs in the color coordinates with respect to the reference white peak, thereby changing the color temperature, thereby changing the color of white.

On the other hand, the higher the color temperature, the more blue is included, and the lower the color temperature, the more red is included. Therefore, in order for the display device to be utilized in various fields and various places, a technology capable of changing the color reproducibility according to the characteristics of the image input when the image is implemented should be proposed.

SUMMARY OF THE INVENTION The present invention for solving the above problems of the background art is to provide an organic light emitting display device which can improve color and display quality by preventing color coordinates or color temperature changes due to luminance changes.

The present invention as a problem solving means described above, the display panel; The gamma reference voltage is set according to the luminance change signal supplied from the outside, the gray level voltage value is generated based on the data value for each gray level and the gain value for each gray level, and the gamma generated based on the set gamma reference voltage and the voltage value for each gray level. A gamma unit configured to output a gamma gray voltage with reference to the voltage; And a data driver for mapping the gamma gray voltage and the data signal output from the gamma unit to the display panel.

The gamma unit may include an operation unit that generates a gray level voltage value by multiplying the gray level data value and the luminance gain value.

The set gamma reference voltage may be set from the white luminance data range to the black luminance data range according to the luminance change signal.

The gray level data value may be a value obtained by measuring an image displayed on the display panel.

The gain value for each luminance may be stored as a ratio of red, green, and blue data for each white luminance.

The luminance-specific gain value is stored as a lookup table in an internal or external memory unit of the data driver, and may be updated with a new luminance-specific gain value according to an external input.

The gamma unit is supplied from a gamma reference voltage setting unit that sets a gamma reference voltage according to a luminance change signal, a gamma voltage generator that generates a gamma voltage based on the set gamma reference voltage and the voltage value for each gray level, and a gamma voltage generator. It may include a gamma gray voltage generator for generating a gamma gray voltage with reference to the gamma voltage.

The gamma voltage generator includes a first gamma voltage generator for generating at least one high gray voltage value and at least one low gray voltage value, and a second gamma voltage generator for generating at least four intermediate gray voltage values. It may include.

The gamma unit may include a register unit that selects a gamma reference voltage, a data value for each gray level, and a gain value for each luminance according to the luminance change signal.

The gamma part may be included in the data driver.

According to the present invention, gamma can be compensated with data values of red, green, and blue corresponding to the changed luminance by using the data value for each gray level and the gain value for each luminance, thereby preventing color coordinates or color temperature changes due to luminance changes, and preventing color and display quality. There is an effect of providing an organic light emitting display device that can improve the.

Hereinafter, with reference to the accompanying drawings, the specific content for the practice of the present invention will be described.

1 is a block diagram of an organic light emitting display device according to an embodiment of the present invention, FIG. 2 is an exemplary circuit diagram of a subpixel shown in FIG. 1, FIG. 3 is a block diagram of a scan driver, and FIG. 4. Is a block diagram of the data driver.

As shown in FIG. 1, an organic light emitting display device according to an exemplary embodiment of the present invention includes a display panel PNL, a timing driver TCN, a scan driver SDRV, a data driver DDRV, and a gamma unit. 60).

The timing driver TCN receives a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, a data enable signal Data Enable (DE), a clock signal CLK, and a data signal DDATA from an external source. The timing driver TCN scans the data driver DDRV using timing signals such as the vertical synchronization signal Vsync, the horizontal synchronization signal Hsync, the data enable signal Data Enable, and the clock signal CLK. The operation timing of the driver SDRV is controlled. Since the timing driver TCN may determine the frame period by counting the data enable signal DE of one horizontal period, the vertical synchronization signal Vsync and the horizontal synchronization signal Hsync supplied from the outside may be omitted. The control signals generated by the timing driver TCN include a gate timing control signal GDC for controlling the operation timing of the scan driver SDRV and a data timing control signal DDC for controlling the operation timing of the data driver DDR. ) May be included. The gate timing control signal GDC includes a gate start pulse (GSP), a gate shift clock (GSC), a gate output enable signal (Gate Output Enable, GOE), and the like. The gate start pulse GSP is supplied to a gate drive integrated circuit (IC) where the first scan signal is generated. The gate shift clock GSC is a clock signal commonly input to the gate drive ICs and is a clock signal for shifting the gate start pulse GSP. The gate output enable signal GOE controls the output of the gate drive ICs. The data timing control signal DDC includes a source start pulse (Source, Start Pulse, SSP), a source sampling clock (SSC), a source output enable signal (Source Output Enable, SOE), and the like. The source start pulse SSP controls the data sampling start time of the data driver DDRV. The source sampling clock SSC is a clock signal that controls the sampling operation of data in the data driver DDRV based on the rising or falling edge. The source output enable signal SOE controls the output of the data driver DDRV. Meanwhile, the source start pulse SSP supplied to the data driver DVV may be omitted according to the data transmission method.

The display panel PNL is formed of an organic light emitting display panel including sub pixels SP arranged in a matrix. The subpixels SP may be formed in a passive matrix type or an active matrix type. When the subpixels SP are formed in an active matrix type, they are composed of a 2T (Capacitor) structure including a switching transistor, a driving transistor, a capacitor, and an organic light emitting diode, or a transistor such as 3T1C, 4T1C, 5T2C, or the like. It may also be of a structure in which a capacitor is further added. The subpixels SP having the above configuration may be formed in a top-emission method, a bottom-emission method, or dual-emission according to a structure.

Meanwhile, the subpixels SP having the 2T1C structure may have a structure as shown in FIG. 2. The switching transistor T1 has a gate connected to the scan line SL1 to which the scan signal is supplied, and one end thereof to the data line DL1 to which the data signal is supplied, and the other end thereof to the first node n1. The driving transistor T2 has a gate connected to the first node n1 and one end of the driving transistor T2 connected to the second node n2 connected to the first power line VDD supplied with the driving power supply Vdd having a high potential. The other end is connected to the node n3. One end of the capacitor Cst is connected to the first node n1 and the other end thereof is connected to the second node n2. In the organic light emitting diode D, an anode is connected to the third node n3 connected to the other end of the driving transistor T2, and a cathode is connected to the second power line VSS to which the driving power Vss of low potential is supplied. .

In the above description, the transistors T1 and T2 included in the sub-pixel SP are configured as N-types as an example, but embodiments of the present invention are not limited thereto. In addition, the high potential driving power Vdd supplied through the first power wiring VDD may be higher than the low power driving power Vss supplied through the second power wiring VSS. The level of power supplied through the VDD) and the second power line VSS may be switched according to the driving method.

The subpixel SP described above may operate as follows. When the scan signal is supplied through the scan line SL1, the switching transistor T1 is turned on. Next, when the data signal supplied through the data line DL1 is supplied to the first node n1 through the turned-on switching transistor T1, the data signal is stored as a data voltage in the capacitor Cst. Next, when the scan signal is blocked and the switching transistor T1 is turned off, the driving transistor T2 is driven in response to the data voltage stored in the capacitor Cst. Next, when the high potential driving power Vdd supplied through the first power line VDD flows through the second power line VSS, the organic light emitting diode D emits light. However, this is only an example of the driving method, the embodiment of the present invention is not limited thereto.

The scan driver SDRV is a swing width of the gate driving voltage at which the transistors of the subpixels SP included in the display panel PNL can operate in response to the gate timing control signal GDC supplied from the timing driver TCN. Scan signals are sequentially generated while shifting the level of the signals. The scan driver SDRV supplies the scan signals generated through the scan lines SL1 to SLm to the subpixels SP included in the display panel PNL.

As shown in FIG. 3, the scan driver SDRV includes gate drive ICs. The gate drive ICs each include a shift register 61, a level shifter 63, and a plurality of AND gates (hereinafter referred to as "AND gates") 62 connected between the shift register 61 and the level shifter 63. And an inverter 64 for inverting the gate output enable signal GOE and the like. The shift register 61 sequentially shifts the gate start pulse GSP according to the gate shift clock GSC using a plurality of D-flip flops connected in a cascade manner. The AND gates 62 generate an output by ANDing the output signal of the shift register 61 and the inverted signal of the gate output enable signal GOE, respectively. The inverter 64 inverts the gate output enable signal GOE and supplies it to the AND gates 62. The level shifter 63 shifts the output voltage swing width of the AND gate 62 to the swing width of the scan voltage at which the transistors included in the display panel PNL can operate. The scan signal output from the level shifter 63 is sequentially supplied to the scan lines SL1 to SLm. The shift register 61 may be formed on the display panel PNL together with the transistors in the process of manufacturing the transistors included in the display panel PNL. In this case, the level shifter 63 may be formed together with the timing driver TCN without being formed on the display panel PNL, or may be formed on a printed circuit board together with the source drive ICs.

The data driver DDRV samples and latches the digital data signal DDATA supplied from the timing driver TCN in response to the data timing control signal DDC supplied from the timing driver TCN, thereby providing data of a parallel data system. Convert to The data driver DVV converts the digital data signal DDATA into a gamma reference voltage and converts it into an analog data signal ADATA. The data driver DDRV supplies the data signal ADATA converted through the data lines DL1 to DLn to the subpixels SP included in the display panel PNL.

As shown in FIG. 4, the data driver DDRV includes source drive ICs. The source drive ICs include a shift register 51, a data register 52, a first latch 53, a second latch 54, a converter 55, an output circuit 56, and the like. The shift register 51 shifts the source sampling clock SSC supplied from the timing driver TCN. The shift register 51 transfers a carry signal CAR to a shift register of a source driver IC of a neighboring next stage. The data register 52 temporarily stores the digital data signal DDATA supplied from the timing driver TCN and supplies it to the first latch 53. The first latch 53 samples and latches a digital data signal DDATA that is serially input according to a clock sequentially supplied from the shift register 51, and then simultaneously outputs the latched data. The second latch 54 latches data supplied from the first latch 53 and then simultaneously outputs the latched data in synchronization with the second latch of the other source drive ICs in response to the source output enable signal SOE. . The converter 55 maps the digital data signal DDATA input from the second latch 54 and the gamma gray voltages G1 to Gn supplied from the gamma unit 60 to convert the analog data signal ADATA. To). The output circuit 56 supplies an analog data signal ADATA to the data lines DL1 to DLn in response to the source output enable signal SOE.

The gamma unit 60 sets a gamma reference voltage according to the luminance change signal CLC supplied from the outside, generates a voltage value for each gray level based on the data value for each gray level and a gain value for each gray level, and sets the gamma reference voltage and the gray level. The gamma gray voltages G1 to Gn are output by referring to the gamma voltage generated based on the group voltage value. The gamma part 60 may be included in the data driver DDRV, but is not limited thereto. The description of the gamma part 60 will be described in more detail below.

Hereinafter, an organic light emitting display device according to an embodiment of the present invention will be described in more detail.

5 is a schematic block diagram of a gamma part according to an embodiment of the present invention, and FIG. 6 is a detailed block diagram of the gamma part shown in FIG. 5.

As shown in FIG. 5, the gamma unit 60 includes a register unit 61, a storage unit 62, a lookup table 63, an operation unit 64, a gamma reference voltage setting unit 66, and a gamma voltage generation unit. And a gamma gray voltage generator 68.

The register unit 61 sets the gamma reference voltage REF_V of the gamma reference voltage setting unit 66 according to the brightness change signal CLC when the luminance change signal CLC is supplied from an external source, for example. The gray level data value GV stored in the storage unit 62 and the luminance gain value LG stored in the lookup table 63 are read and provided to the calculation unit 64. That is, the register unit 61 selects the gamma reference voltage REF_V, the grayscale data value GV, and the luminance-specific gain value LG according to the luminance change signal CLC.

The storage unit 62 may be configured as a device such as a read only memory (ROM). The grayscale data value GV stored in the storage 62 may be a value obtained by measuring an image displayed on the display panel PNL through a measuring device or the like.

The lookup table 63 may be configured as an element such as an internal or external memory unit. The lookup table 63 stores the gain value LG for each luminance set as a ratio of red, green, and blue data for each white luminance. The lookup table 63 may be included in an internal or external memory of the data driver DDRV, and the gain-specific gain LG in the lookup table 63 may be updated to a new value according to an external input.

The calculation unit 64 calculates the gray level data values GV read out by the register unit 61 and the gain value LG for each luminance to generate voltage values RGB_AM2 to RGB_GR0 for each gray level. The calculator 64 may generate voltage values RGB_AM2 to RGB_GR0 for each gray level by multiplying the gray level data value GV and the luminance-specific gain value LG, but the present invention is not limited thereto. The gray level voltage values RGB_AM2 to RGB_GR0 generated by the calculator 64 are supplied to the gamma voltage generator 67.

The gamma reference voltage setting unit 66 sets the gamma reference voltage REF_V according to the first register value Reg1 of the register unit 61 according to the luminance change signal CLC and sets the gamma reference voltage REF_Vm set by this value. , REF_V1 may be transmitted to the gamma voltage generator 67 as the second register value Reg2, but the present invention is not limited thereto.

The gamma voltage generator 67 generates a gamma voltage V0 to Vm based on the gamma reference voltage set by the gamma reference voltage setting unit 66 and the gray level voltage values RGB_AM2 to RGB_GR0 calculated by the calculation unit 64. Create The gamma voltage generator 67 may include at least one first gamma voltage generator 67a for generating at least one high gray voltage value RGB_AM2 and at least two low gray voltage values RGB_AM1 and RGB_AM0. The second gamma voltage generator 67b may generate a voltage value RGB_GR0 to RGB_GR3 of the intermediate gray level. The first gamma voltage generator 67a may supply gamma reference voltages REF_Vm and REF_V0 to the second gamma voltage generator 67b. In addition, the first gamma voltage generator 67a may supply the gamma reference voltage REF_V0 to the gamma gray voltage generator 68.

The gamma gray voltage generator 68 generates gamma gray voltages G1 to Gn with reference to the gamma voltages V0 to Vm supplied from the gamma voltage generator 67. The gamma gray voltages G1 to Gn generated by the gamma gray voltage generator 68 are supplied to the converter 55 included in the data driver DVV.

As shown in FIG. 6, when the luminance change signal CLC is supplied from the system or the user, the register unit 61 may set the first register value (ie, the gamma reference voltage REF_V according to the luminance change signal CLC) to be set. Reg1) is supplied to the gamma reference voltage setting unit 66. In addition, the register unit 61 reads out the gray level data value GV according to the luminance change signal CLC from the storage unit 62 and supplies it to the calculation unit 64. In addition, the register unit 61 reads the gain-specific gain value LG according to the luminance change signal CLC from the lookup table 63 and supplies it to the calculation unit 64. For example, in the case of the storage unit 62, one of gray level data values GV such as " RGB_AM2 to RGB_GR0 " is read by the register unit 61 and supplied to the operation unit 64. In the case of the lookup table 63, one of the gain values LG for each luminance, such as "Gain 1 to Gain n," is read by the register unit 61 and supplied to the calculation unit 64.

Thus, in the case of the gamma reference voltage setting unit 66, the gamma reference voltage REF_V is set to a specific value, and in the calculation unit 64, the data value GV for each gray level and the gain value LG for each luminance are changed. It becomes the supplied state. The gamma reference voltage setting unit 66 transmits the information on the set gamma reference voltage REF_V to the gamma voltage generation unit 67 as a second register value Reg2. The calculator 64 multiplies the grayscale data value GV and the luminance-specific gain value LG to generate the grayscale voltage values RGB_AM2 to RGB_GR0 suitable for the luminance change signal CLC, and then generates the gamma voltage generator 67. ) Is supplied to the first gamma voltage generator 67a and the second gamma voltage generator 67b. In this case, the first gamma voltage generator 67a receives at least one high gray voltage value RGB_AM2 and at least two low gray voltage values RGB_AM1 and RGB_AM0 from the calculator 64. In the case of the second gamma voltage generator 67b, the calculator 64 receives the voltage values RGB_GR0 to RGB_GR3 of at least four intermediate gray levels.

The gamma voltage generating unit 67 is based on the gamma reference voltage REF_V set by the gamma reference voltage setting unit 66 and the gray level voltage values RGB_AM2 to RGB_GR0 supplied from the calculating unit 64, and " V0 to V255 " Gamma voltages V0 to Vm are generated and supplied to the gamma gray voltage generator 68. In this case, the gamma voltages V0 to Vm generated by the gamma voltage generator 67 may be generated as 64 gray scales or 256 gray scales according to the gray scale, but are not limited thereto.

The gamma gray voltage generator 68 generates a gamma gray voltage G1 to Gn such as "G0 to G255" with reference to the gamma voltages V0 to Vm supplied from the gamma voltage generator 67, and generates the data driver. It is supplied to the conversion unit 55 included in. Then, the conversion unit 55 maps the digital data signal DDATA and the gamma gray voltages G1 to Gn supplied from the gamma unit 60 to convert the data signal DDATA into an analog data signal ADATA. Accordingly, the output circuit 56 included in the data driver can supply the analog data signal ADATA supplied from the converter 55 to the display panel.

Hereinafter, changes in color coordinates and color temperature when white luminance is changed will be described with reference to the white luminance according to the related art and the white luminance according to the exemplary embodiment of the present invention.

7 is a white luminance graph according to the prior art, Figure 8 is a white luminance graph according to an embodiment of the present invention. In the graphs of FIGS. 7 and 8, "sample_1, sample_2, and sample_3" represent color temperatures of white luminance for red, green, and blue, respectively.

In the prior art, a gamma reference voltage is set to represent a white luminance desired by a user. Next, based on the set gamma reference voltage, gray, gradation voltage values corresponding to desired color temperature and gamma characteristics are set. Next, the set gamma reference voltage and the gradation voltage values of red, green, and blue are stored in the storage unit, and a data signal is generated based on the stored gamma reference voltage. The prior art uses a fixed gradation voltage value when changing the white peak brightness in the user or outside. Therefore, in the related art, as shown in the white luminance graph of FIG. 7, the color coordinates change according to the white peak luminance, and thus the color temperature changes, thereby causing a change in color.

On the other hand, in one embodiment of the present invention, a gamma reference voltage is set to indicate a white luminance desired by a user. Next, a gray level voltage value and a brightness level gain value for red, green, and blue colors that maintain the same color temperature and color as the white peak brightness are set, and a gray level voltage value is generated based on the gray level voltage value. Next, the gamma voltage may be generated based on the set gamma reference voltage and the gray level voltage value to match the gamma reference voltage and luminance of red, green, and blue. Therefore, in the exemplary embodiment of the present invention, even if the white peak luminance is changed as shown in the white luminance graph of FIG. 8, gamma can be corrected for the same color coordinate and color temperature.

As described above, the present invention can compensate gamma with red, green, and blue data values corresponding to the changed luminance by using the data value for each gray level and the gain value for each brightness, thereby preventing color coordinates or color temperature changes according to the luminance change, and preventing color and display quality. There is an effect of providing an organic light emitting display device that can improve the.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood that the invention may be practiced. Therefore, the embodiments described above are to be understood as illustrative and not restrictive in all aspects. In addition, the scope of the present invention is shown by the claims below, rather than the above detailed description. Also, it is to be construed that all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts are included in the scope of the present invention.

1 is a block diagram of an organic light emitting display device according to an embodiment of the present invention.

FIG. 2 is an exemplary circuit diagram of a subpixel illustrated in FIG. 1. FIG.

3 is a block diagram of a scan driver.

4 is a block diagram of a data driver.

5 is a schematic block diagram of a gamma part according to an embodiment of the present invention.

FIG. 6 is a detailed block diagram of the gamma part shown in FIG. 5. FIG.

7 is a white luminance graph according to the prior art.

8 is a white luminance graph according to an embodiment of the present invention.

<Explanation of symbols on main parts of the drawings>

PNL: Display panel TCN: Timing driver

SDRV: Scan driver DDRV: Data driver

60: gamma part 61: register part

62: storage 63: lookup table

64: calculator 66: gamma reference voltage setting unit

67: gamma voltage generator 68: gamma gray voltage generator

Claims (10)

Display panel; The gamma reference voltage is set according to the luminance change signal supplied from the outside, the gray level voltage value is generated based on the data value for each gray level and the gain value for each gray level, and generated based on the set gamma reference voltage and the voltage value for each gray level. A gamma unit configured to output a gamma gray voltage with reference to the gamma voltage; And And a data driver for mapping the gamma gray voltage and the data signal output from the gamma part to the display panel. The method of claim 1, The gamma part, And a calculator configured to multiply the data value for each gray level and the gain value for each luminance to generate the voltage value for each gray level. The method of claim 1, The set gamma reference voltage is, And a black luminance data range from a white luminance data range according to the luminance change signal. The method of claim 1, The grayscale data value is And a value obtained by measuring an image displayed on the display panel. The method of claim 1, The gain value for each luminance is An organic light emitting display device, characterized in that stored in a ratio of red, green, and blue data for each white luminance. The method of claim 1, The gain value for each luminance is An organic light emitting display device which is stored as a lookup table in an internal or external memory unit of the data driver and updated with a new gain value for each luminance according to an external input. The method of claim 1, The gamma part, A gamma reference voltage setting unit which sets the gamma reference voltage according to the brightness change signal; A gamma voltage generator configured to generate a gamma voltage based on the set gamma reference voltage and the gray level voltage value; And a gamma gray voltage generator configured to generate a gamma gray voltage by referring to the gamma voltage supplied from the gamma voltage generator. The method of claim 7, wherein The gamma voltage generator, A first gamma voltage generator configured to generate at least one high gray voltage value and at least one low gray voltage value; An organic light emitting display device comprising a second gamma voltage generator for generating voltage values of at least four intermediate gray levels. The method of claim 1, The gamma part, And a register unit for selecting the gamma reference voltage, the data value for each gray level, and the gain value for each luminance according to the brightness change signal. The method of claim 1, The gamma part, An organic light emitting display device, characterized in that included in the data driver.

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