KR20170131804A - Display device - Google Patents

Abstract

The present invention relates to a display apparatus capable of mitigating luminance degradation of a display apparatus due to pixel deterioration. The display apparatus comprises: a display panel having pixels; a gamma control part calculating a usage amount of the pixels and correcting a gamma register based on the usage amount to output a gamma control signal; and a data driving part generating a reference gamma voltage based on the gamma control signal.

Description

Display device {DISPLAY DEVICE}

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a display device, and more particularly to a display device capable of compensating for a decrease in luminance due to pixel deterioration.

The organic light emitting display device can display an image by emitting an organic light emitting diode based on input data. The characteristics of the organic light emitting diode and the driving transistor for supplying current to the organic light emitting diode may be deteriorated by use. The organic light emitting display device can not display an image having a desired luminance according to deterioration of the organic light emitting diode and the driving transistor (hereinafter referred to as "pixel deterioration").

In recent years, a deterioration compensation technique for compensating a tone value corresponding to a pixel by using a stress profile that defines a deterioration ratio according to a usage amount of a pixel has been proposed. On the other hand, the deterioration compensation technique is a technique of first scaling (e.g., downscaling) the gradation value to prevent the final gradation value (i.e., the compensated gradation value) from exceeding the maximum gradation value, And compensates the scaled gradation value. In this case, deterioration of the display quality due to pixel deterioration can be prevented, but the luminance of the display device is further reduced by the degradation of the efficiency of the display device due to deterioration of the pixels and the scaling (e.g., downscaling) Lower.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a display device capable of mitigating a decrease in luminance of a display device due to pixel deterioration.

It should be understood, however, that the present invention is not limited to the above-described embodiments, and may be variously modified without departing from the spirit and scope of the present invention.

In order to accomplish one object of the present invention, a display device according to embodiments of the present invention includes a display panel having pixels; A gamma control unit for calculating a usage amount of the pixel and correcting the gamma register based on the usage amount to output a gamma control signal; And a data driver for generating a reference gamma voltage based on the gamma control signal.

According to an embodiment, the data driver includes: a resistance column for dividing a reference voltage; And a distribution circuit for selecting one of the outputs of the resistor string based on the gamma control signal and outputting the reference gamma voltage.

According to an embodiment, the gamma control unit may include: a deterioration calculation block which accumulates the gray level values corresponding to the pixels to calculate the usage amount of the pixels; An offset calculation block for calculating a gamma offset for correcting the gamma register based on the usage amount; And a brightness control block for correcting the gamma register based on the gamma offset and outputting the gamma control signal.

According to an embodiment, the offset calculation block may calculate the offset ratio based on the usage amount, and calculate the gamma offset by multiplying the maximum gamma offset and the offset ratio.

According to an embodiment, the offset ratio may increase stepwise as the usage amount increases.

According to an exemplary embodiment, the brightness control block may generate the gamma control signal by summing the gamma register and the gamma offset.

According to an embodiment, the gamma control unit may further include a storage block that stores the usage amount and periodically updates the usage amount.

According to an embodiment, the offset calculation block may calculate the gamma offset based on the usage amount stored in the storage block at the time of initial driving of the display device.

In order to accomplish one object of the present invention, a display device according to embodiments of the present invention includes a display panel having pixels; Calculating a usage amount of the pixel, receiving a user dimming step from an external device, correcting the user dimming step based on the usage amount to calculate a final dimming step, and outputting a gamma control signal corresponding to the final dimming step A gamma control unit; And a data driver for generating a reference gamma voltage based on the gamma control signal.

According to an embodiment, the data driver includes: a resistance column for dividing a reference voltage; And a distribution circuit for selecting one of the outputs of the resistor string based on the gamma control signal and outputting the reference gamma voltage.

According to an embodiment, the gamma control unit may include: a deterioration calculation block which accumulates the gray level values corresponding to the pixels to calculate the usage amount of the pixels; An offset calculating block for calculating a dimming offset for correcting the user dimming step based on the usage amount; And a brightness control block for calibrating the user dimming step based on the dimming offset to calculate the final dimming step.

According to an embodiment, the offset calculation block may calculate the dimming offset by calculating an offset ratio based on the usage amount, and multiplying the maximum dimming offset and the offset ratio.

According to an embodiment, the offset ratio may increase stepwise as the usage amount increases.

According to an embodiment, the brightness control block may calculate the final dimming step by summing the user dimming step and the dimming offset.

According to an embodiment, the gamma control unit may further include a storage block that stores the usage amount and periodically updates the usage amount.

According to an embodiment, the offset calculation block may calculate the dimming offset based on the usage amount stored in the storage block at an initial driving time of the display device.

In order to accomplish one object of the present invention, a display device according to embodiments of the present invention includes a display panel having pixels; A gamma control unit for calculating a usage amount of the pixel, receiving a dimming step from an external device, calculating a final dimming step by correcting the dimming step based on the usage amount, and outputting a dimming control signal corresponding to the final dimming step, ; And a light emitting driver for adjusting a light emission time of the pixel based on the dimming control signal.

According to an embodiment, the gamma control unit may include: a deterioration calculation block which accumulates the gray level values corresponding to the pixels to calculate the usage amount of the pixels; An offset calculating block for calculating a dimming offset for correcting the user dimming step based on the usage amount; And a brightness control block for calibrating the user dimming step based on the dimming offset to calculate the final dimming step.

According to an embodiment, the offset calculation block may calculate the dimming offset by calculating an offset ratio based on the usage amount, and multiplying the maximum dimming offset and the offset ratio.

According to an embodiment, the brightness control block may calculate the final dimming step by summing the user dimming step and the dimming offset.

The display device according to the embodiments of the present invention accumulates tone values corresponding to pixels to calculate USAGE (or stress data), calculates a gamma offset (SP_OFFSET) based on USAGE, The gamma register GAMMA_REGISTER can be corrected based on the gamma offset SP_OFFSET. In this case, the display device can adjust the gamma offset SP_OFFST in the direction of increasing the luminance as the usage USAGE increases (or as the pixel deterioration progresses), thereby generating the upward gamma voltages. Therefore, the display apparatus 100 can prevent or minimize a decrease in luminance due to pixel deterioration.

In addition, the display device can calculate the dimming offset DVB_OFFSET based on the usage amount USAGE and correct the user dimming step WRDISBV received from the external device (or the user) based on the dimming offset DBV_OFFSET. The display device can increase the dimming offset (DVB_OFFSET) as the usage (USAGE) increases (or as pixel deterioration progresses). Therefore, the display apparatus 100 can prevent or minimize a decrease in luminance due to pixel deterioration.

However, the effects of the present invention are not limited to the above effects, and may be variously extended without departing from the spirit and scope of the present invention.

1 is a block diagram showing a display device according to embodiments of the present invention.
2 is a diagram showing an example of a data driver included in the display device of FIG.
3 is a diagram illustrating an example of a gamma offset generated in the gamma control unit included in the display apparatus of FIG.
4 is a block diagram showing an example of a gamma control unit included in the display device of FIG.
5 is a diagram illustrating an example of the offset ratio generated by the gamma controller of FIG.
6 is a block diagram showing an example of a gamma control unit included in the display device of FIG.
7 is a view for explaining driving of the display device of Fig.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The same or similar reference numerals are used for the same components in the drawings.

1 is a block diagram showing a display device according to embodiments of the present invention.

1, a display device 100 includes a display panel 110, a timing controller 120, a gamma controller 130, a scan driver 140, a data driver 150, a light emitting driver 160, (Not shown). The display apparatus 100 can display an image based on input data (for example, first data (DATA1)) provided from an external apparatus. For example, the display apparatus 100 may be an organic light emitting display.

The display panel 110 may include the gate lines S1 to Sn, the data lines D1 to Dm, the emission control lines E1 to En and the pixel 111 ). The pixel 111 may be disposed at an intersection region of the gate lines S1 to Sn, the data lines D1 to Dm, and the emission control lines E1 to En.

The pixel 111 stores a data signal (i.e., a data signal provided through the data lines D1 to Dm) in response to a gate signal (that is, a gate signal provided through the gate lines S1 to Sn) In response to the light emission control signals (that is, the light emission control signals provided through the light emission control lines E1 to En), light can be emitted at a luminance corresponding to the data signals.

In embodiments, the pixel 111 may include sub-pixels, respectively. For example, the pixel 111 may include a first sub-pixel emitting a first color (e.g., red), a second sub-pixel emitting a second color (e.g., green) And a third sub-pixel that emits blue light, for example.

The timing controller 120 may convert input data to be available in the data driver 150 and control the scan driver 140 and the data driver 150. For example, the timing controller 120 generates a gate drive control signal and supplies the generated gate drive control signal to the scan driver 140. The timing controller 120 generates a data drive control signal and supplies modulation data (for example, (DATA2) and a data driving control signal to the data driver 150. [

The gamma control unit 130 calculates the usage amount of the pixel 111 based on the input data and generates the gamma control signal GAMMA_OUTPUT and / or the dimming control signal DL (or the light emission drive control signal) can do. The usage amount of the pixel 111 is the stress (or stress data) received by the pixel 111 according to the use of the pixel 111, and the tone value corresponding to the pixel 111, It can be proportional to time. The gamma control signal GAMMA_OUTPUT is a set value for adjusting the reference gamma voltage which is a reference of the gamma voltage (that is, the gamma voltage constituting the data signal provided to the display panel 110 in correspondence to the gray level value) Setting values). The dimming control signal DL may be a control signal for adjusting the emission time (or on-duty) of the pixel 111. [

The gamma control unit 130 calculates the amount of use of the pixel 111 by accumulating the gray level value corresponding to the pixel 111, calculates the gamma offset based on the usage amount, And output the gamma control signal GAMMA_OUTPUT. Here, the gamma register may include the set values corresponding to the reference gamma voltages to generate the reference gamma voltages in accordance with a gamma curve (e.g., gamma curve 2.2), and may be preset. The gamma register and the gamma offset will be described in detail with reference to FIGS. 3 and 4. FIG.

In embodiments, the gamma control unit 130 receives a user dimming step (WRDISBV) from an external device (e.g., a user interface) and corrects the user dimming step (WRDISBV) based on the usage of the pixel 111 The final dimming step may be calculated and the gamma control signal GAMMA_OUTPUT and / or the dimming control signal DL corresponding to the final dimming step may be output. Here, the user dimming step (WRDISBV) may be one selected by the user among the dimming steps (for example, 256 dimming steps).

That is, the gamma control unit 130 may calculate the amount of use of the pixel 111, correct the gamma register based on the usage amount of the pixel 111, or correct the user dimming step WRDISBV. In this case, the display apparatus 100 displays an image with a higher luminance (for example, luminance compensated for luminance degradation due to pixel deterioration) based on the corrected gamma register or the corrected user dimming step (WRDISBV) can do.

1, the gamma controller 130 is shown as being independent of the timing controller 120 and the data driver 150, but the gamma controller 130 is not limited thereto. For example, the gamma control unit 130 may be implemented in the timing controller 120 or may be included in the data driver 150. FIG.

The scan driver 140 (or the gate driver) may generate a gate signal based on the gate drive control signal. The gate driver control signal includes a start signal (or a start pulse) and clock signals, and the scan driver 140 includes gate drive units (or shifts) that sequentially generate a gate signal based on the start signal and the clock signals Registers).

The data driver 150 generates reference gamma voltages based on the gamma control signal GAMMA_OUTPUT and generates a data signal corresponding to the modulation data (e.g., the second data DATA2) using the reference gamma voltages . The configuration for generating the reference gamma voltages will be described in detail with reference to FIG. Meanwhile, the data driver 130 may provide a data signal to the display panel 110 in response to the data driving control signal.

The light emission driving unit 160 generates the light emission control signal based on the dimming control signal DL (or the light emission drive control signal) and supplies the light emission control signal to the pixels 111 through the light emission control lines E1 to En Can supply. The light emission driving unit 150 may determine the on duty (or the light emission period) and / or the off duty (or the non-light emission period) of the pixel 111 based on the dimming control signal DL. The pixel 111 emits light in response to a light emission control signal having a logic low level (or a low voltage, a low voltage level, or a turn-on voltage) and outputs a light emission control signal having a logic high level (or high voltage, high voltage level, It is possible to emit no light in response to the signal.

The power supply unit 170 may generate a driving voltage necessary for driving the display device 100. [ The driving voltage may include a first power supply voltage ELVDD and a second power supply voltage ELVSS. The first power supply voltage ELVDD may be greater than the second power supply voltage ELVSS.

As described above, the display device 100 according to the embodiments of the present invention calculates the amount of use of the pixel 111 based on the input data (for example, the first data (DATA1)), (WRDISBV), and display the image with a higher luminance based on the corrected gamma register or the corrected user dimming step (WRDISBV). Therefore, the display device 100 can relieve the luminance degradation due to pixel deterioration.

Before describing the configuration for correcting the gamma register in the gamma controller 130, a description will be given of a gamma register (that is, a configuration for generating a gamma voltage using a gamma register).

2 is a diagram showing an example of a data driver included in the display device of FIG. 3 is a diagram illustrating an example of a gamma offset generated in the gamma control unit included in the display apparatus of FIG.

2 and 3, the data driver 150 (or the gamma voltage generator 200) includes resistance columns 211 and 212 and distribution circuits 221, 222 and 223, To generate reference gamma voltages V0 through V255 (e.g., reference gamma voltages for the first sub-pixel). The reference gamma voltages V0 to V255 are supplied to specific grayscale values (for example, from 0 grayscale to 255 grayscale) in accordance with a gamma curve (for example, a curve representing a relationship between grayscales and gamma voltages, Can respond.

The first resistor row 211 can divide the reference voltage VREG1. For example, the first row of resistors 211 may comprise resistors that are connected in series between the reference voltage VREG1 and the ground voltage.

The first distribution circuit 211 may select one of the outputs of the first resistor string 211 based on the bottom control signal CRT and output it as a bottom voltage VT. The first distribution circuit 221 may be a 16 * 1 multiplexer (16-to-1 multiplexer).

The second distribution circuit 211 may select one of the outputs of the first resistor string 211 based on the tenth control signal CR9 and output it as the tenth reference gamma voltage V255. For example, the second distribution circuit 222 may be a 512 * 1 multiplexer (512-to-1 multiplexer).

The second resistance column 212 may include first through ninth sub-resistive columns and the third distribution circuit 223 may include first through ninth sub-distributors. Here, the first to ninth subdividers may be a 256-to-1 multiplexer.

Regarding the ninth reference gamma voltage V203, the ninth sub-resistor row divides the bottom voltage VT and the tenth reference gamma voltage V255, and the ninth sub- Thereby selecting and outputting one of the outputs of the ninth sub-resistor row.

Similarly, the eighth sub-resistor row divides the bottom voltage VT and the ninth reference gamma voltage V203, and the eighth sub-divider divides the output of the eighth sub-resistor row based on the eighth control signal CR7 One can be selected and output as the eighth reference gamma voltage V151.

That is, the ith sub-resistor row (where i is an integer of 3 or more) divides the bottom voltage VT and the i + 1 reference gamma voltage, and the i-th sub divider divides the i- One of the outputs of the column can be selected and output as the ith reference gamma voltage.

In relation to the second reference gamma voltage V1, the second sub-resistor row divides the reference voltage VREG1 and the third reference gamma voltage V11, and the second sub-divider divides the reference voltage VREG1 and the third reference gamma voltage V11 based on the second control signal CR1 So that one of the outputs of the second sub-resistor row can be selected and output.

Similarly, the first sub-resistor row divides the reference voltage VREG1 and the second reference gamma voltage V1, and the first sub-divider divides the output of the first sub-resistor row based on the first control signal CR0 And may output one as the first reference gamma voltage V0.

2, the data driver 150 (or the gamma voltage generator 200) may generate gamma voltages by dividing the reference gamma voltages VO through V255.

Referring to FIG. 3, the gamma register may include first through ninth control signals CR0 through CR9 and a bottom control signal CRT (or their corresponding set values). Since the pixel 111 described with reference to FIG. 1 includes the first through third sub-pixels, the gamma register may include control signals CR0-CR9, CRT0, and CR2 to generate reference gamma voltages V0 through V255 for each sub- , CG0-CG9, CGT, CB0-CB9 and CBT) (or corresponding set values).

2, the second distribution circuit 222 for outputting the tenth reference gamma voltage V255 may be implemented as a 512 * 1 multiplexer (512-to-1 multiplexer). In this case, , And the tenth control signal CR9 (or CG9, CB9), 9-bit data can be assigned.

Similarly, the first distribution circuit 221, which outputs the bottom voltage VT, may be implemented as a 16 * 1 multiplexer, in which case the bottom control signal CRT (or CGT , CBT) can be assigned 4 bits of data. The third distribution circuit 223 (or subdividers) for outputting the first to ninth reference gamma voltages V0 to V203 may be implemented as a 256-to-1 multiplexer, In this case, 8 bits of data may be allocated to the setting values for the first to ninth control signals CRn (or CGn, CBn) (where n is a positive integer of 9 binary).

As described with reference to FIGS. 2 and 3, the data driver 150 generates the reference gamma (or gamma) based on the gamma control signal (or the first through tenth control signals CR0 through CR9 and the bottom control signal CRT) And generates the voltages V0 to V255 and the gamma register supplies the gamma control signal (or the first to tenth control signals CR0 to CR9 and the bottom control signal CRT) (or the gamma control signal Setting value).

4 is a block diagram showing an example of a gamma control unit included in the display device of FIG.

4, the gamma control unit 130 may include a deterioration calculation block 410, an offset calculation block 420, a storage block 430, and a brightness control block 440. Referring to FIG.

The degradation calculation block 410 can calculate the usage amount USAGE of the pixel 111 (or the stress data of the pixel 111) by accumulating the gray level values. Here, the gray level value is included in the first data (DATA1) and can correspond to the pixel 111. [ For example, the degradation calculation block 410 may downsample the first data (DATA1) and periodically accumulate the downscaled first data (DATA1) to calculate the USAGE of the pixel (111) .

The offset calculation block 420 may calculate the gamma offset SP_OFFSET based on the usage USAGE. Here, the gamma offset SP_OFFSET may include setting values for correcting the gamma register GAMMA_REGISTER (or the gamma setting register). For example, the gamma offset SP_OFFSET may have substantially the same data structure as the gamma register GAMMA_REGISTER described with reference to FIG.

The offset calculation block 420 calculates the offset ratio OFFSET_RATIO based on the usage amount USAGE and calculates the gamma offset SP_OFFSET by multiplying the maximum gamma offset SP_OFFSET_MAX and the offset ratio OFFSET_RATIO Can be calculated. Here, the maximum gamma offset (SP_OFFSET_MAX) is a maximum value that the gamma offset (SP_OFFSET) can have, and the offset ratio (OFFSET_RATIO) can be included in the range of 0 to 1.

In embodiments, the offset ratio (OFFSET_RATIO) is linear with USAGE and can increase stepwise as the usage (USAGE) increases.

5 is a diagram illustrating an example of the offset ratio generated by the gamma controller of FIG.

Referring to FIG. 5, the horizontal axis represents the usage amount (USAGE), and the vertical axis represents the size of the offset ratio (OFFSET_RATIO). The usage amount USAGE is divided into a plurality of sections, and the offset ratio (OFFSET_RATIO) corresponding to a specific section may have a constant value. The maximum value 60 of the usage amount USAGE shown in FIG. 5 is illustrative and may vary depending on the calculation method of the usage amount USAGE. However, the usage amount when the display device 100 is driven for about 20,000 hours For example, the maximum lifetime of the pixel 111). The offset ratio (OFFSET_RATIO) can be set in units of 0.1, considering the size of the maximum gamma offset (SP_OFFSET_MAX).

Referring again to FIG. 4, the store block 430 may store and update the USAGE computed in the degradation computation block 410, and may include a maximum gamma offset (SP_OFFSET_MAX) and a gamma register (GAMMA_REGISTER). The storage block 430 further includes a panel gamma offset OTP_OFFSET and the panel offset OTP_OFFSET includes setting values for compensating the gamma register GAMMA_REGISTER in consideration of the characteristic deviation of the display panel 110 And has a data structure substantially the same as the gamma register GAMMA_REGISTER described with reference to FIG. 3, and may be stored in the storage block 430 at the time of manufacturing the display device 100.

The brightness control block 440 may generate the gamma control signal GAMMA_OUTPUT based on the gamma register GAMMA_REGISTER, the gamma offset SP_OFFSET, and the panel offset OTP_OFFSET.

For example, the brightness control block 440 calculates the final gamma setting value based on the following equation (1) and provides the gamma control signal GAMMA_OUTPUT corresponding to the final gamma setting value to the data driver 150 can do.

[Equation 1]

Here, the Final Gamma Output is a final gamma setting value, the Gamma Register is a gamma register (GAMMA_REGISTER), the Gamma offset is a panel offset (OTP_OFFSET), and the SP Offset may be a gamma offset (SP_GAMMA_OFFSET).

4 and 5, the gamma setting unit 130 calculates a usage amount USAGE (or stress data) of the pixel 111 and calculates a gamma offset SP_OFFSET based on the usage amount USAGE, And can output the gamma control signal GAMMA_OUTPUT by correcting the gamma register GAMMA_REGISTER based on the gamma offset SP_OFFSET. Since the gamma offset SP_OFFST is adjusted in the direction of increasing the luminance as the usage USAGE increases or as the pixel deterioration proceeds, the reference gamma voltages (or the reference gamma voltages) generated based on the gamma control signal GAMMA_OUTPUT , Gamma voltages) can be raised as a whole. Therefore, even if pixel deterioration occurs, the display device 100 can prevent or minimize a decrease in luminance.

6 is a block diagram showing an example of a gamma control unit included in the display device of FIG.

Referring to FIG. 6, the gamma control unit 130 may include a deterioration calculation block 610, an offset calculation block 620, a storage block 630, and a brightness control block 640. The degradation computation block 610, the offset computation block 620, the storage block 630 and the brightness control block 640 are the same as the degradation computation block 410, the offset computation block 420, 430 and the brightness control block 440. In this case, Therefore, redundant description is not repeated.

The gamma controller 130 of FIG. 4 may adjust gamma voltages in consideration of pixel deterioration when a gamma register (GAMMA_REGISTER) (or a gamma curve) is set by the user, and the gamma controller 130 of FIG. (Or the light emission time period) of the pixel 111 when the user dimming step (or the brightness level, brightness of the display device 100) is set by the user and not the gamma register GAMMA_REGISTER, ) Can be adjusted. That is, the gamma control unit 130 of FIG. 6 receives the user dimming step (WRDISBV), corrects the user dimming step (WRDISBV) based on the usage amount USAGE, and the corrected user dimming step (or final dimming step) By outputting the gamma control signal GAMMA_OUTPUT corresponding to the gamma voltage. Meanwhile, the user dimming step (WRDISBV) may be one selected from the 255 brightness stages of the display device 100. [

The offset calculation block 620 may calculate the dimming offset DVB_OFFSE based on the usage USAGE. Here, the dimming offset DVB_OFFSET may include setting values for correcting the user dimming step WRDISBV. For example, the dimming offset (DVB_OFFSET) may be the number of luminance steps to be adjusted (or the step difference between the user dimming stage (WRDISBV) and the final dimming stage).

In the embodiments, the offset calculation block 620 calculates the offset ratio (OFFSET_RATIO) based on the usage amount USAGE and multiplies the maximum dimming offset DBV_OFFSET_MAX and the offset ratio OFFSET_RATIO to obtain the dimming offset DBV_OFFSET Can be calculated. Here, the maximum dimming offset DBV_OFFSET_MAX is the maximum value that the dimming offset DBV_OFFSET can have, and the offset ratio OFFSET_RATIO can be included in the range of 0 to 1. On the other hand, the offset ratio (OFFSET_RATIO) is linear with the USAGE as described with reference to FIG. 5, and may increase stepwise as the usage (USAGE) increases.

Storage block 630 may include a maximum dimming offset (DVB_OFFSET_MAX). In addition, the store block 630 may store and update the USAGE and may include a gamma register (GAMMA_REGISTER) and a panel gamma offset (OTP_OFFSET).

The brightness control block 640 receives the user dimming step WRDISBV and generates the gamma control signal GAMMA_OUTPUT and / or the dimming control signal DL based on the user dimming step WRDISBV and the dimming offset DVB_OFFSET .

In embodiments, the brightness control block 640 may sum the user dimming step (WRDISBV) and the dimming offset (DVB_OFFSET) to yield the final dimming step, and the gamma control signal (GAMMA_OUTPUT) corresponding to the final dimming step and / It is possible to generate the dimming control signal DL. For example, the brightness control block 640 may use a look-up table indicating the relationship between the final dimming step and the gamma register (GAMMA_REGISTER) (or the gamma register compensated by the panel offset (OTP_OFFSET) It is possible to output the gamma control signal GAMMA_OUTPUT. Similarly, the brightness control block 640 may output a dimming control signal DL corresponding to the final dimming step using a look-up table indicating the relationship between the final dimming step and the dimming control signal DL. That is, the brightness control block 640 calculates the final dimming step and generates a control signal for adjusting the gamma voltages and the emission time (i.e., the emission time or on-duty of the pixel 111) based on the final dimming step / Output.

On the other hand, since the dimming offset (DVB_OFFSET) is set to compensate for the luminance degradation due to pixel deterioration, it can have only a positive value that moves the luminance stage in the positive direction.

6, the gamma setting unit 130 calculates the dimming offset DVB_OFFSET based on the usage amount USAGE and outputs the user dimming step WRDISBV received from the external device (or user) to the dimming offset (GAMMA_OUTPUT) and / or the dimming control signal (DL) by correcting it based on the reference voltage (DBV_OFFSET). Since the dimming offset DVB_OFFSET increases as the usage USAGE increases (or as pixel deterioration progresses) and the final dimming step is upward, the display device 100 prevents or suppresses a decrease in luminance due to pixel deterioration, Can be minimized.

7 is a view for explaining driving of the display device of Fig.

Referring to FIGS. 1, 4 and 7, the display device 100 (or the offset calculation block 420) is based on the usage amount USAGE stored in the storage block 430 at the time of initial operation of the display device 100 To calculate a gamma offset (SP_OFFSET). Similarly, the display device 100 (or the offset calculation block 620) may be configured to determine a usage amount stored in the storage block 630 at the time of initial operation of the display device 100 (USAGE (DVB_OFFSET).

The synchronization signal VSYNC shown in FIG. 7 synchronizes the operation of the display device 100 and the sleep-out signal SLEPP-OUT synchronizes the operation of the display device 100 (for example, Lt; / RTI >

The usage amount USAGE may be calculated in the previous driving period of the display apparatus 100 and stored in the storage block 430. [ That is, the usage amount USAGE is calculated while the display device 100 is driven and stored in the storage block 430, and while the display device 100 is in the sleep-out state (or while the display device 100 is stopped) ).

When the display device 100 is initially driven (that is, wakes up from the sleep-out state) at the first time point T1, the display device 100 receives the usage amount USAGE), and calculate the gamma offset (SP_OFFSET) based on the usage (USAGE).

At the second time point T2, the display apparatus 100 generates the gamma control signal GAMMA_OUTPUT based on the calculated gamma offset SP_OFFSET, and at the third time point T3, the display apparatus 100 performs the gamma control (That is, the display device 100 can generate gamma voltages based on the gamma control signal GAMMA_OUTPUT).

Before the third time point T3, the gamma control signal GAMMA_OUTPUT does not reflect the gamma offset SP_OFFSET, so that the initial gamma control signal GAMMA_OUTPUT set based on the predetermined gamma register GAMMA_REGISTER (and the panel offset OTP_OFFSET) INITIAL GAMMA). After the third time point T3, the gamma control signal GAMMA_OUTPUT is set to reflect the gamma offset SP_OFFSET and can be expressed as the final gamma control signal FINAL GAMMA, distinguished from the initial gamma control signal GAMMA_OUTPUT have.

The display device 100 can continuously calculate the usage amount USAGE. For example, the display apparatus 100 can calculate / update the stress data by accumulating gray level values. However, the display apparatus 100 may store the usage amount USAGE in the storage block 430, and may not generate the new gamma control signal GAMMA_OUTPUT. For example, even if the display apparatus 100 is continuously used for a long time (for example, 15 hours), the gamma offset (OFFSET) set based on the usage amount USAGE does not change by more than one step (or, Since the offset ratio (OFFSET_RATIO) described with reference to FIG. 5 does not change more than one level. That is, the display apparatus 100 calculates the gamma offset SP_OFFSET only at the initial driving of the display apparatus 100, and calculates the gamma offset SP_OFFSET (that is, Gamma offset SP_OFFSET) of the gamma control signal GAMMA_OUTPUT.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, the above description is illustrative and not restrictive, and various changes and modifications may be made by those skilled in the art without departing from the technical spirit of the invention. And may be changed.

The present invention can be variously applied to an electronic apparatus having a display device. For example, the present invention can be applied to a computer, a notebook, a mobile phone, a smart phone, a smart pad, a PMP, a PDA, an MP3 player, a digital camera, a video camcorder,

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made therein without departing from the spirit and scope of the invention as defined in the appended claims. You will understand.

100: display device 110: display panel
111: pixel 120: timing control unit
130: gamma control unit 140:
150: Data driver 160:
170: power supply unit 200: gamma voltage generator
211: first resistance column 212: second resistance column
221 to 223: First to third distribution circuits
410: degradation calculation block 420: offset calculation block
430: storage block 440: brightness control block
610: deterioration calculation block 620: offset calculation block
630: Storage block 640: Brightness control block

Claims (20)

A display panel having pixels;
A gamma control unit for calculating a usage amount of the pixel and correcting the gamma register based on the usage amount to output a gamma control signal; And
And a data driver for generating a reference gamma voltage based on the gamma control signal. The data driver according to claim 1,
A resistor row for dividing the reference voltage; And
And a distribution circuit for selecting one of the outputs of the resistance series based on the gamma control signal and outputting the reference gamma voltage. The apparatus of claim 1, wherein the gamma controller comprises:
A deterioration calculating block for accumulating gray level values corresponding to the pixels to calculate the usage amount of the pixels;
An offset calculation block for calculating a gamma offset for correcting the gamma register based on the usage amount; And
And a brightness control block for correcting the gamma register based on the gamma offset and outputting the gamma control signal. The display device according to claim 3, wherein the offset calculation block calculates an offset ratio based on the usage amount, and calculates the gamma offset by multiplying the maximum gamma offset and the offset ratio. 5. The display device according to claim 4, wherein the offset ratio increases stepwise as the usage amount increases. 6. The display device of claim 5, wherein the brightness control block generates the gamma control signal by summing the gamma register and the gamma offset. The apparatus of claim 3, wherein the gamma control unit comprises:
Further comprising a storage block for storing the usage amount and periodically updating the usage amount. The display device according to claim 7, wherein the offset calculation block calculates the gamma offset based on the usage amount stored in the storage block at the time of initial driving of the display device. A display panel having pixels;
Calculating a usage amount of the pixel, receiving a user dimming step from an external device, correcting the user dimming step based on the usage amount to calculate a final dimming step, and outputting a gamma control signal corresponding to the final dimming step A gamma control unit; And
And a data driver for generating a reference gamma voltage based on the gamma control signal. The data driver as claimed in claim 9,
A resistor row for dividing the reference voltage; And
And a distribution circuit for selecting one of the outputs of the resistance series based on the gamma control signal and outputting the reference gamma voltage. The apparatus of claim 9, wherein the gamma control unit comprises:
A deterioration calculating block for accumulating gray level values corresponding to the pixels to calculate the usage amount of the pixels;
An offset calculating block for calculating a dimming offset for correcting the user dimming step based on the usage amount; And
And a brightness control block for correcting the user dimming step based on the dimming offset to calculate the final dimming step. The display device according to claim 11, wherein the offset calculation block calculates the offset ratio based on the usage amount, and calculates the dimming offset by multiplying the maximum dimming offset and the offset ratio. 13. The display device according to claim 12, wherein the offset ratio increases stepwise as the usage amount increases. 14. The display device according to claim 13, wherein the brightness control block calculates the final dimming step by summing the user dimming step and the dimming offset. 13. The apparatus of claim 12, wherein the gamma control unit comprises:
Further comprising a storage block for storing the usage amount and periodically updating the usage amount. The display device according to claim 15, wherein the offset calculation block calculates the dimming offset based on the usage amount stored in the storage block at the time of initial driving of the display device. A display panel having pixels;
A gamma control unit for calculating a usage amount of the pixel, receiving a dimming step from an external device, calculating a final dimming step by correcting the dimming step based on the usage amount, and outputting a dimming control signal corresponding to the final dimming step, ; And
And a light emitting driver for adjusting a light emission time of the pixel based on the dimming control signal. The apparatus of claim 17, wherein the gamma control unit comprises:
A deterioration calculating block for accumulating gray level values corresponding to the pixels to calculate the usage amount of the pixels;
An offset calculating block for calculating a dimming offset for correcting the user dimming step based on the usage amount; And
And a brightness control block for correcting the user dimming step based on the dimming offset to calculate the final dimming step. The display device according to claim 11, wherein the offset calculation block calculates the offset ratio based on the usage amount, and calculates the dimming offset by multiplying the maximum dimming offset and the offset ratio. 14. The display device according to claim 13, wherein the brightness control block calculates the final dimming step by summing the user dimming step and the dimming offset.

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