KR101510690B1 - Driving Circuit For Automatic Adjustment Of Grey Level Voltage Using Transfer Function And Display Device Including The Same - Google Patents

Abstract

Provided is a driving circuit for automatically adjusting a gray voltage using a transfer function, the driving circuit comprising a transfer function operating unit to operate gray voltage information and inclination information from brightness of an image using a transfer function; a color balance processing unit to receive the gray voltage information and the inclination information; and a gamma voltage generating unit to generate multiple gamma voltages according to control of the color balance processing unit. The gamma voltage generating unit includes a reference voltage generating unit including multiple reference resistances which are connected in serial between high potential power voltages and low potential power voltages; an amplitude inclination adjusting unit including multiple multiplexers which are connected to nodes among the reference resistances to be overlapped with each other; and a gamma interpolating unit including multiple gamma resistances which are connected to the multiplexers, thereby maintaining the output brightness of the uniform inclination.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving circuit for automatically adjusting a gray scale voltage using a transfer function and a display device including the same,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving circuit for automatically adjusting a gradation voltage, and more particularly, to a driving circuit for automatically adjusting a gradation voltage using a transfer function, a display including the same, and a driving method thereof.

An organic light emitting diode (OLED) display device, which is one of a flat panel display (FPD), has high luminance and low operating voltage characteristics.

In addition, since it is a self-luminous type that emits light by itself, it has a large contrast ratio, can realize an ultra-thin display, has a short response time of several microseconds (μs), easy to implement a moving image, And is driven at a voltage as low as about 5 to 15 V of direct current, so that it is easy to manufacture and design a driving circuit.

In addition, since the manufacturing process of the organic light emitting diode display device is all of evaporation and encapsulation, the manufacturing process is very simple.

However, the organic light emitting diode display device still has many problems to be solved. First, the organic light emitting diode display device has a lower manufacturing yield than the liquid crystal display device. In order to increase the manufacturing yield, the manufacturing process deviation of the thin film transistor and the light emitting diode (Threshold voltage) deviation of the thin film transistor, critical point deviation of the organic film material, and the like must be overcome.

Secondly, in the organic light emitting diode display device, efficiency variation between red, green, and blue (R, G, B) subpixels varies according to the decrease in lifetime, The lifetime and efficiency of the diode must be improved to have stable uniformity. Particularly, the difference in the luminance variation of the light emitting diodes of each sub-pixel due to the ambient temperature fluctuation and the light leakage current fluctuation,

Third, the organic light emitting diode display device has a static voltage drop (IR drop) due to a resistance difference in each position of a power supply wiring for supplying a cell driving voltage to the light emitting diodes of each subpixel, The cell drive voltage supplied to each subpixel due to the static voltage drop and the dynamic voltage drop depends on the variation of the display position and the amount of data, It is necessary to solve such a difference between the static voltage drop and the dynamic voltage drop since the display luminance appears as a crosstalk phenomenon in which the luminance is partially changed.

In order to solve the problems of the organic light emitting diode display device, various correction methods are being performed during or after the manufacturing process. All the correction methods are performed by using a look up table ).

A conventional gamma correction method using such a look up table will be described with reference to the drawings.

1 is a view showing a conventional driving circuit for a display device.

1, the conventional display device drive circuit 10 includes a control register 20 for holding a set value for gamma characteristic adjustment, a gradation voltage generation circuit 30, a gradation voltage generation circuit 30, And a decoding unit 50 for decoding the data.

The control register 20 includes an amplitude adjustment register 22 and a curve adjustment register 24.

The individual gradation voltage generating circuit 30 for red, green and blue has a ladder resistor 32 and a reset resistor 34 provided between a reference voltage supplied from the outside and a ground voltage, Selector circuits 36 and 38 for selecting a gradation reference voltage from a plurality of voltage levels generated by division, an operational amplifier circuit 40 for buffering the output voltages of the selector circuits 36 and 38, an operational amplifier circuit 40, An operational amplifier circuit 44 for buffering the voltage generated by the variable resistor 42, and a variable resistor 42 for dividing the output voltage of the operational amplifier circuit 44 by a desired number of gradations (for example, And an output section ladder resistor 46 for linearly dividing the voltage by a gradation voltage of 64 gradation voltages.

The selector circuit 36 provided at the upper side of the ladder resistor 32 sets the voltage level by the maximum gradation voltage setting value of the amplitude adjustment register 22 and the selector circuit 38 The voltage level is set by the minimum gradation voltage setting value of the amplitude adjustment register 22 so that the voltage selected by the selector circuits 36 and 38 is set as the gradation reference voltage at both ends of the gradation number, Is set by the amplitude adjustment register (22).

The resistance value of the variable resistor 42 is set by the variable resistor setting value of the curve adjustment register 24. [

In such a conventional display apparatus drive circuit 10, the amplitude adjustment register 22 is constituted by the upper and lower selector circuits 36 and 38 having a selection period in which a part of the amplitude adjustment register 22 overlaps a part of the amplitude adjustment register 22 so that the maximum gradation voltage and the minimum gradation voltage can be adjusted And the lower selector circuit 38 has a resistor selection period that is denser than the upper selector circuit 36, thereby minimizing malfunction in the low gradation region.

However, in the conventional display device driver circuit 10, since the reset resistor 34 is used for the threshold voltage, adjustment of the threshold voltage is limited, and the gradation voltage output from the output section ladder resistor 46 It is difficult to obtain desired display quality by making the luminance characteristic curve.

In addition, it is difficult to realize the resistance value setting by the automatic calculation due to the non-uniformity of the resistance value of the output section ladder resistor 46 and the disconnection continuity disconnection for each section, and the resistance value of the preset output section ladder resistor 46 is varied It is a limitation to implement the gradation voltage.

That is, a difference in efficiency of the transfer function occurs when energy conversion is performed between the input gradation voltage and the output luminance of the display device. In particular, in the current adjustment method of the serial LED of the self-luminous display device, There is a problem that the white balance is distorted due to unevenness of the brightness of the entire screen caused by unevenness of the brightness of red, green, and blue brightness, and the display quality is deteriorated.
In setting the input gradation voltage by the output luminance, there is a problem that it is difficult to automate the input gradation voltage due to the restriction of finding an approximate value in the number of cases.

Korean Patent Publication No. 10-2004-0103782

SUMMARY OF THE INVENTION The present invention has been made in order to solve such a problem, and it is an object of the present invention to provide a method and an apparatus for generating a gradation voltage in consideration of a transfer function in a gradation voltage generator, The present invention has an object to provide a driving circuit for automatic adjustment of gradation voltage in which the difference in efficiency between gradations of a transfer function is compensated and the output luminance is maintained at a uniform slope and a display device including the same.

The present invention also provides a driving circuit for automatic adjustment of a gradation voltage in which a deviation per block is minimized by generating a gradation voltage so that transfer function factors such as gradation voltage information and slope information in a plurality of blocks of the display panel are the same, It is another object to provide a display device.

According to an aspect of the present invention, there is provided an image processing apparatus including a transfer function arithmetic unit for calculating gradation voltage information and slope information from a luminance of an image using a transfer function; A color balance processor receiving the gradation voltage information and the slope information; And a gamma voltage generator for generating a plurality of gamma voltages under the control of the color balance processor, wherein the gamma voltage generator comprises: a reference voltage generator A voltage generator; An amplitude tilt adjusting unit including a plurality of muxes connected to overlap the nodes between the plurality of reference resistors; And a gamma interpolation unit including a plurality of gamma resistors connected to the plurality of muxes.

The plurality of reference resistors may have the same resistance value, and the number of the plurality of muxes may be less than or equal to the number of the reference resistances. In particular, It may be 2 ^m times (m is natural number) times the number of muxes.

The total number of gradations corresponding to the number of bits of the final data used for the display of the image may be the sum of the number of the plurality of muxes and the number of the plurality of gamma It can be equal to the product of the number of resistors.

The plurality of gamma resistors may have the same resistance value.

The gamma voltage generator may further include: a fixed voltage generator including a plurality of fixed resistors connected in series between the high potential power supply voltage and the low potential power supply voltage; And a plurality of fixed muxes connected to the nodes between the plurality of fixed resistors so as to overlap with each other, wherein a plurality of fixed voltages outputted from the plurality of fixed muxes are connected between the plurality of reference resistors Lt; / RTI > node.

The driving circuit for automatically adjusting gradation voltages using the transfer function may further include a critical point compensator for generating additional data and adding the generated additional data to input data used for displaying the image to generate final data.

Each of the input data and the additional data corresponds to an upper bit and a lower bit of the final data, and the additional data may be generated only when the input data is valid, It can be mapped by level.

The driving circuit for automatically adjusting the gradation voltage using the transfer function may further include a residual anti-aging preventing unit for reversing the polarity of the input data according to a preset reversal period.

The transfer function calculating unit may be configured in an arithmetic unit outside the color balance processing unit, or integrated in the color balance processing unit.

The transfer function calculator includes a tilt processor for generating a tilt control signal according to the tilt information and transmitting the tilt control signal to the color balance processor; An amplitude controller for generating an amplitude control signal according to the maximum voltage information of the gradation voltage information and transmitting the amplitude control signal to the color balance processor; A gamma calculator for generating a gamma control signal according to the tilt information and transmitting the gamma control signal to the color balance processor; A critical point correcting unit for generating a critical point control signal for generating additional data and transmitting the critical point control signal to the color balance processing unit; A residual anti-aging processor for generating a residual anti-aging control signal for polarity reversal of input data and transmitting the generated residual anti-aging control signal to the color balance processor; And a dimming adjustment unit for generating a dimming control signal for reducing the luminance according to the dimming information and transmitting the dimming control signal to the color balance processing unit.

The transfer function calculator may calculate a transfer function y = A * (x / dx) ^r + B, where Y is luminance, x is the number of tones, dx is the total number of tones, (x / dx) ^{1 / r} + b), y is the gradation voltage, V is the total gradation voltage, x is the number of gradations and dx is the total number of gradations) The luminance transfer function and the voltage transfer function are adjusted by adjusting the slope efficiency transfer factor (r, 1 / r) and the threshold point efficiency transfer factor (B, b) Can be calculated.

When the luminance transfer function passes the minimum luminance point (n0, L0), the intermediate luminance point (n1, L1) and the maximum luminance point (n2, L2), the correlation between the luminance transfer function and the voltage transfer function The intermediate luminance L1 and the maximum luminance L2 and the threshold voltage V0 and the intermediate voltages V1 and V2 corresponding to the minimum luminance point, the intermediate luminance point and the maximum luminance point, respectively, The maximum voltage V2 satisfies (L1-L0) / (L2-L0) = (V0-V1) ^r / (V0-V2) ^r and the threshold voltage V0 satisfies V0 = V2 + ) / {1 - ((L1-L0) / (L2-L0)) ^{1 / r} }.

According to another aspect of the present invention, there is provided an image processing apparatus including a transfer function arithmetic unit for calculating gradation voltage information and tilt information from a luminance of an image of first and second blocks of a display panel using a transfer function; A color balance processor receiving the gradation voltage information and the slope information; And a first gamma voltage generator for generating a plurality of first and second gamma voltages under the control of the color balance processor, respectively, wherein the first gamma voltage generator comprises: a high gamma voltage generator A reference voltage generating unit including a plurality of reference resistors connected in series between the reference voltage generating unit and the reference voltage generating unit; A first amplitude tilt adjusting unit including a plurality of first muxes connected to overlap each other at nodes between the plurality of reference resistors; And a plurality of first gamma resistors coupled to the plurality of first muxes, wherein the second gamma voltage generator comprises: the reference voltage generator; A second amplitude tilt adjusting unit including a plurality of second muxes connected to overlap the nodes between the plurality of reference resistors; And a second gamma interpolation unit including a plurality of second gamma resistors connected to the plurality of second muxes, wherein the plurality of first gamma voltages of the first gamma voltage generation unit are applied to the first block, And a plurality of second gamma voltages of the two gamma voltage generators provides a driving circuit for automatically controlling the gray scale voltage using a transfer function applied to the second block.

On the other hand, the present invention provides a display device comprising: a display panel for displaying an image; A transfer function arithmetic unit for calculating the gradation voltage information and the slope information from the luminance of the image using the transfer function as a driving circuit for supplying a data signal to the display panel; A color balance processor receiving the gradation voltage information and the slope information; And a gamma voltage generator for generating a plurality of gamma voltages under the control of the color balance processor, wherein the gamma voltage generator comprises: a plurality of reference lines connected in series between a high potential power supply voltage and a low potential power supply voltage; A reference voltage generating unit comprising a resistor; An amplitude tilt adjusting unit including a plurality of muxes connected to overlap the nodes between the plurality of reference resistors; And a gamma interpolation unit comprising a plurality of gamma resistors connected to the plurality of muxes.

On the other hand, the present invention comprises a display panel divided into first to fourth blocks and displaying an image; A luminance meter for measuring luminance of the image of the first to fourth blocks; A first driving circuit for supplying a data signal to the first and second blocks of the display panel, the transfer function calculating unit calculating the gradation voltage information and the slope information from the luminance of the image using the transfer function; A first color balance processor receiving the gradation voltage information and the slope information; A first driving circuit comprising first and second gamma voltage generators for generating a plurality of first and second gamma voltages under the control of the first color balance processor; A second driving circuit for supplying the data signal to the third and fourth blocks of the display panel, the transfer function calculating unit; A second color balance processor receiving the gradation voltage information and the slope information; A second driving circuit comprising third and fourth gamma voltage generators for generating a plurality of third and fourth gamma voltages under the control of the second color balance processor; And a signal processing center for converting the gradation voltage information and the initial code into a digital signal and transmitting the digital signal to the first and second driving circuits.

The first gamma voltage generator includes: a first reference voltage generator including a plurality of first reference resistors connected in series between a high potential power supply voltage and a low potential power supply voltage; A first amplitude tilt adjusting unit including a plurality of first muxes connected to nodes between the plurality of first reference resistors to overlap each other; And a first gamma interpolation unit including a plurality of first gamma resistors coupled to the plurality of first muxes, wherein the second gamma voltage generator comprises: the first reference voltage generator; A second amplitude tilt adjusting unit including a plurality of second muxes connected to overlap each other at a node between the plurality of first reference resistors; And a second gamma interpolation unit composed of a plurality of second gamma resistors connected to the plurality of second muxes, wherein the third gamma voltage generator is connected in series between the high potential power supply voltage and the low potential power supply voltage A second reference voltage generating unit including a plurality of second reference resistors; A third amplitude tilt adjusting unit including a plurality of third muxes connected to overlap each other at a node between the plurality of second reference resistors; And a third gamma interpolation unit including a plurality of third gamma resistors connected to the plurality of third muxes, wherein the fourth gamma voltage generating unit comprises: the second reference voltage generating unit; A fourth amplitude tilt adjusting unit including a plurality of fourth muxes connected to overlap each other at a node between the plurality of second reference resistors; And a fourth gamma interpolation unit including a plurality of fourth gamma resistors coupled to the plurality of fourth muxes, wherein the plurality of first gamma voltages of the first gamma voltage generation unit are applied to the first block, A plurality of second gamma voltages of the second gamma voltage generator are applied to the second block, a plurality of third gamma voltages of the third gamma voltage generator are applied to the third block, A plurality of fourth gamma voltages may be applied to the fourth block.

The transfer function calculator may calculate the minimum luminance among the maximum luminance of the first to fourth blocks, reduce the maximum luminance in the first to fourth blocks to the calculated minimum luminance value, To the fourth block, and the threshold voltage in the first to fourth blocks is increased to the calculated threshold luminance maximum value to calculate the gradation voltage information and the slope information have.

In the present invention, by generating a reference voltage in consideration of the transfer function in the reference voltage generator of the driving circuit, the gradation voltage is automatically adjusted so that the white balance, the color balance, the gamma gradient and the maximum target luminance of the display device are uniformly maintained The yield is improved and the manufacturing cost is reduced.

In the present invention, a gradation voltage is generated so that transfer function factors such as gradation voltage information and gradation information are the same in a plurality of driving methods of each block of a display panel, thereby minimizing the block-by-block variation and improving the display quality on the entire screen .

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view showing a conventional drive circuit for a display device. Fig.
BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a display device including a driving circuit for automatically adjusting a gray scale voltage using a transfer function according to the first embodiment of the present invention.
3 is a view illustrating a gamma voltage generator of a driving circuit for automatically adjusting a gray scale voltage using a transfer function according to the first embodiment of the present invention.
4 is a view illustrating an amplitude tilt adjusting unit of a driving circuit for automatically adjusting a gray scale voltage using a transfer function according to a first embodiment of the present invention.
5 is a view showing a critical point compensating unit and a residual image aging preventing unit of a driving circuit for automatic adjustment of gradation voltage using a transfer function according to the first embodiment of the present invention.
6 is a waveform diagram of signals used in the critical point compensating unit and the afterimage antialiasing unit of the driving circuit for automatic adjustment of gradation voltage using the transfer function according to the first embodiment of the present invention.
7A, 7B and 7C are diagrams illustrating a luminance graph, a gradation voltage graph, and a reference voltage generator used for threshold voltage, amplitude, and maximum voltage adjustment in the driving circuit for automatic adjustment of gradation voltage according to the first embodiment of the present invention .
8A is a diagram illustrating a voltage transfer function and a luminance transfer function used in a driving circuit for automatic adjustment of gradation voltage using a transfer function according to the first embodiment of the present invention.
FIG. 8B is a view showing a program process of a result of automatic gradation voltage adjustment by the driving circuit for automatic adjustment of gradation voltage using the transfer function according to the first embodiment of the present invention; FIG.
9 is a view illustrating a display device including a driving circuit for automatic adjustment of gradation voltage using a transfer function according to a second embodiment of the present invention.
FIG. 10 is a diagram showing first and second amplitude tilt adjusting units 262a and 262b of a driving circuit for automatic adjustment of gradation voltage using a transfer function according to the second embodiment of the present invention. FIG.
11 is a diagram showing first and second gamma interpolation sections 264a and 264b of a driving circuit for automatic adjustment of gradation voltage using a transfer function according to the second embodiment.
FIG. 12 is a block diagram illustrating a first threshold value compensating unit 251a, a first afterimage anti-aging unit 252a, and a first block selecting unit 255a of a driving circuit for automatic adjustment of gradation voltage using a transfer function according to the second embodiment of the present invention. Fig.
13A is a diagram illustrating a voltage transfer function and a luminance transfer function used in a driving circuit for automatic adjustment of gradation voltage using a transfer function according to a second embodiment of the present invention.
13B is a view illustrating a dimming adjustment unit of a driving circuit for automatically adjusting a gray scale voltage using a transfer function according to a second embodiment of the present invention.
13C is a diagram illustrating a driving power source generating unit of a driving circuit for automatically adjusting a gray scale voltage using a transfer function according to a second embodiment of the present invention.
FIG. 14 illustrates a driving circuit for automatic adjustment of gradation voltage using a transfer function according to the third embodiment of the present invention; FIG.

In the driving circuit for automatic adjustment of gradation voltage according to the present invention, the transfer function calculator calculates a luminance transfer function (Y = A * (x / dx) ^r + B) and a voltage transfer function A) and the slope efficiency transfer factor (r, 1 / ^r + b) to set the correlation between the slope efficiency transfer function (y = V- (a * r) and a critical point efficiency transfer factor (B, b) so as to match the luminance transfer function and the voltage transfer function to calculate the gradation voltage information, and the slope efficiency factor is calculated by using a slope function efficiency R is the luminance slope value in the x gradation of the luminance slope function r (x), and 1 / r is the voltage slope in the x gradation of the voltage slope function 1 / kr (x) Maintaining the relationship between the slope value and the constant (k), adjusting the efficiency transfer factors so that the relationship between the two transfer functions in the previous gradation is correlated by the slope function, And the color balance processor automatically generates a reference voltage corresponding to the gradation voltage information by using the reference resistance of the gamma voltage generator so that the gradation voltage is adjusted to the gradation voltage The basic principle is to adjust automatically.

The present invention can be implemented by defining a concrete embodiment according to the basic principle as follows

In the first and the first modified examples, the transfer function calculation unit of the transfer function calculation unit receives the measured luminance, calculates the gradation voltage information using the correlation of the transfer function, and performs color balance processing in the drive circuit The reference voltage corresponding to the gradation voltage information is generated using the reference resistance of the additional gamma voltage generator. The transfer function calculator outside the driving circuit includes an application programming interface (API) calculation engine of an external computing device such as a computer, When the transfer function calculation unit is formed outside the drive circuit, the gradation voltage information is input to the drive circuit, and when the transfer function calculation unit is formed in the drive circuit, the measured luminance is input to the drive circuit.

In the second embodiment, the display panel is divided into a plurality of blocks, and a plurality of gamma voltages are generated using transfer functions different from one another for each of the plurality of drive circuits.

In the third embodiment, by forming the fixed voltage generator at the front end of the reference voltage generator of the gamma voltage generator, the large slope can be adjusted first by the fixed voltage generator and the small slope can be adjusted later by the reference voltage generator to increase the overall slope accuracy , The total number of resistors can be reduced.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the present embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout.

FIG. 2 is a diagram illustrating a display device including a driving circuit for automatically adjusting a gray scale voltage using a transfer function according to the first embodiment of the present invention. Referring to FIG.

2, the display device according to the first exemplary embodiment of the present invention includes a driving circuit 110 for automatically generating a gradation voltage adjusted using transfer function factors such as gradation voltage information and gradient information, A display panel 120 for displaying an image using the generated gradation voltage, a transfer function factor calculator for calculating transfer function factors such as gradation voltage information and gradation information from the luminance of the image displayed using the transfer function, And a transfer function arithmetic unit 180 for transferring a transfer function factor such as inclination information to the drive circuit 110.

The driving circuit 110 includes a gradation voltage input section 131, a slope input / output section 132, a maximum voltage amplitude input / output section 133, a dimming communication section 134, an initial code communication section 135, a color balance processing section 136, A lifetime compensation memory 149, a detection current memory 150, and a memory 150. The lifetime register memory 137, the factory reset memory 138, the RGB pattern generation unit 139, the driving power supply generation unit 146, the temperature compensation processing unit 147, Green, and blue threshold correction units 151R, 151G, 151B, red, green, and blue anti-aging units 152R, 152G, 152B, red, green, and blue DAC Analog-to-digital converters 153R, 153G, and 153B, an output buffer unit 154, and the like.

The color balance processing unit 136 performs a basic function of automatically setting a plurality of reference resistors (Rref in Fig. 3) so that each gradation voltage calculated from the voltage transfer function is outputted as a plurality of reference voltages (Vref in Fig. 3) The amplitude processing unit 141, the gamma computing unit 142, the critical point correction unit 143, the residual image degradation processing unit 144, and the dimming adjustment unit 144 of the transfer function computing unit 180 as an additional function, The gamma voltage generator 160, the critical point compensators 151R, 151G, and 151B, and the afterimage anti-aging unit 150, according to a plurality of control signals, 152R, 152G, and 152B.

The gradation voltage input section 131 transfers the gradation voltage information input from the transfer function arithmetic section 180 to the color balance processing section 136. [

The tilt input / output unit 132 transmits the tilt information input from the transfer function operation unit 180 to the color balance processing unit 136 or transmits / receives the tilt information to / from another drive circuit of the display device to match the tilt efficiency transfer factor of the tilt information .

The maximum voltage amplitude input / output unit 133 transmits the maximum voltage amplitude information inputted from the transfer function operation unit 180 to the color balance processing unit 136 or transmits and receives the maximum voltage amplitude information to another driving circuit of the display device, And serves to match the maximum voltage amplitude efficiency transfer factor of the information. Here, the characteristic of the transfer function is that the minimum voltage amplitude of the gradation voltage is determined by the threshold voltage of the light emitting diodes (DeR, DeG DeB) of the display panel 120 and the minimum luminance can be set to "0" The adjusted gradation voltage and threshold voltage can be calculated using the maximum voltage amplitude information.

Considering the characteristics of the sensory organs, it can be seen that the number of gradations (n) and the luminance (L) are exponentially proportional (L ~ n ^r ). Considering the luminance transfer function and the voltage transfer function, And the luminance (L) are exponentially proportional (V ~ L ^{1 / r} or L ~ V ^r ).

Thus, the luminance transfer function calculated from the measured luminance is the minimum luminance point (n0, L0), the intermediate luminance point (n1, L1 (n2)) corresponding to the minimum gradation (n0), the intermediate gradation (Ln) between the minimum luminance (L0) and the maximum luminance (L2) and the minimum luminance (V0) between the minimum luminance (L0) and the maximum luminance (L2) due to the exponential- ) And the maximum voltage (V2) satisfy the equation (1).

(Ln-L0) / (L2-L0) = A + C * (V0-Vn) ^r -

It can be seen from this that A = 0 from the luminance (Ln = L0) and the gradation voltage (Vn = V0) of the minimum luminance point and C = 1 / (V0 -V2) ^r .

Therefore, the luminance L1 of the intermediate luminance point and the gradation voltage V1 can be expressed by Equation 2, from which the gradation voltage V0 (threshold voltage) of the minimum luminance point can be expressed by the following equation (3).

(L1-L0) / (L2-L0) = (V0 - V1) ^r / (V0 - V2) ^r -

V0 = V2 + [(V1 - V2) / {1 - ((L1 - L0) / (L2 - L0)) ^{1 / r} }

In particular, when the luminance L0 of the minimum luminance point is 0, the gradation voltage V0 of the minimum luminance point can be expressed by the following equation (4).

V0 = V2 + [(V1 - V2) / {1- (L1 / L2) ^{1 / r} }

Therefore, the adjusted gradation voltage and threshold voltage can be calculated from the maximum voltage amplitude information.

The dimming communication unit 134 transmits the dimming information set by the user to the color balance processing unit 136. The color balance processing unit 136 transmits the dimming information to the dimming adjusting unit 145 of the transfer function calculating unit 180, Signal.

The initial code communication unit 135 transfers the register value for the gamma resistance and the register value for the information for setting the basic conditions of the driving circuit 110 to the color balance processing unit 136 and the setting unit.

The life register memory 137 stores lifetime information necessary for performing the life compensation of the life compensation processing unit 148. Upon receiving the current information stored in the current detection memory 149 during the environmental test under special conditions, It is possible to store the change in the amount of current due to the decrease in life and the life information for comparing and compensating the value stored in the life register.

The factory reset memory 138 stores the gamma-related environment information that has been normally adjusted after the display device is manufactured. If the user desires to initialize the information, And provides a reference value for compensating the variation in the amount of current due to the change.

The RGB pattern generator 139 generates input data (for example, 8 bits) corresponding to a specific pattern in a special environment used for calculating transfer function factors such as gradation voltage information and gradient information.

The transfer function calculator 180 calculates a luminance transfer function and a voltage transfer function using the luminance measured from the image displayed by the display panel 120 and calculates transfer functions such as gradation voltage information and gradient information from the voltage transfer function The transfer function calculator 180 calculates the transfer function of the transfer function calculator 180 based on the transfer function calculated by the transfer function calculator 180. The transfer function calculator 180 includes a tilt processor 140, an amplitude processor 141, a gamma calculator 142, a critical point corrector 143, A dimming adjustment unit 145, a gradation luminance input unit 181, and a maximum luminance amplitude input / output unit 182. [

The grayscale luminance input unit 181 transmits luminance information of an image input from the luminance meter (not shown) to the transfer function calculator 180. [

The maximum luminance amplitude input / output unit 182 transmits the maximum luminance amplitude information input from the luminance measuring unit to the transfer function calculating unit 180 or transmits and receives the maximum luminance amplitude information to another driving circuit of the display device and outputs the maximum luminance amplitude information And serves to match the amplitude efficiency transfer factor.

The tilt processor 140 generates a tilt control signal according to the tilt information and transmits the tilt control signal to the color balance processor 136. The color balance processor 136 adjusts the amplitude tilt of the gamma voltage generator 160 based on the tilt control signal 162).

The amplitude processing unit 141 generates an amplitude control signal according to the maximum voltage information and transmits the amplitude control signal to the color balance processing unit 136. The color balance processing unit 136 adjusts the amplitude tilt of the gamma voltage generating unit 160, Lt; / RTI >

The gamma calculator 142 generates a gamma control signal according to the tilt information and transmits the gamma control signal to the color balance processor 136. The color balance processor 136 receives the gamma control signal from the gamma interpolator 164.

The critical point correction unit 143 generates a critical point control signal for generating additional data corresponding to the gradation voltage at the low luminance and transmits the critical point control signal to the color balance processing unit 136. The color balance processing unit 136, And controls the compensation units 151R, 151G, and 151G.

Image anti-aging processing unit 144 generates a residual anti-aging control signal for polarity reversal of the input data and transmits the residual anti-aging control signal to the color balance processing unit 136. The color balance processing unit 136 subjects the residual anti-aging prevention unit 152R , 152G, and 152B.

The dimming adjusting unit 145 generates a dimming control signal for reducing the luminance under the setting conditions such as red, green, blue color balance or white balance according to the dimming information, and transmits the dimming control signal to the color balance processing unit 136, 136 control the driving power source generation unit 146 in accordance with the dimming control signal.

In the first embodiment, the transfer function arithmetic unit 180 may be realized by a separate arithmetic unit such as a computer outside the display device including the driving circuit 110. In the modification of the first embodiment, The transfer function calculator 180 may be integrated into the drive circuit 110 to form a single chip (IC). That is, the driving circuit 110 including the color balance processor 136 integrated with the transfer function calculator 180 receives the measured luminance, calculates a transfer function factor such as gradation voltage information and gradation information, And the gradation information can be automatically generated using the transfer function factor such as the gradation information. In this case, the grayscale brightness input section 181 transmits the brightness information to the transfer function arithmetic section 180 of the color balance processing section 136, and the maximum brightness amplitude input / output section 182 transmits the maximum brightness amplitude information to the color balance processing section 136 To the transfer function calculating unit 180.

The driving power source generating unit 146 generates and supplies various power source voltages required for the driving circuit 110.

The temperature compensation processing unit 147 compares the information on the operating temperature detected by the temperature sensor T with the specific environmental measurement pattern and the specific condition at a constant cycle and the current consumption amount obtained under the specific condition according to the information, The color balance processor 136 may generate the dimming control signal reflecting the environmental information in conjunction with the dimming adjuster 145. The color balance processor 136 may adjust the dimming control signal to reflect the environmental information The drive power generation unit 146 can be controlled according to the signal. For example, the color balance processing unit 136 may control the driving power source generation unit 146 so that the corresponding low potential power source voltage VDDL is raised or lowered according to the environment information, It is possible to maintain a good display quality uniformly and to reduce power consumption regardless of a change in temperature.

The threshold correction units 151R, 151G and 151G are provided for each of the red, green and blue colors. The threshold correction units 151R, 151G and 151G generate additional data (for example, 2 bits) corresponding to the gray- Added final data to the input data to generate final data. That is, by replacing the gradation voltage at the low luminance including the threshold luminance with the voltage corresponding to the additional data, instability of the gradation voltage at low luminance can be solved.

The anti-aging parts 152R, 152G, and 152B are made up of red, green, and blue colors. The anti-aging parts 152R, 152G, and 152B reverse the polarity of the input data at regular intervals according to the residual image aging control signal. In other words, by inverting the polarity of the input data, the contrast ratio is improved, the aging balance of pixels with high frequency of use is matched with the frequency of use, and the partial lifetime difference due to long-time use of a specific pattern is leveled. At this time, since the self-emission display device has a relatively high response speed, the inversion of the input data must be performed within a time that does not affect the visibility.

The gamma voltage generator 160 generates a plurality of gamma voltages corresponding to the tilt information, the maximum voltage information, and the luminance amplitude information. The gamma voltage generator 160 includes a reference voltage generator 161, an amplitude tilt adjusting unit 162, a reference voltage buffer unit A reference voltage generator 163 and a gamma interpolation unit 164 of the gamma voltage generator 160. The gamma interpolator 163 and the gamma interpolator 164. The reference voltage generator 161, May be configured for red, green, and blue, respectively.

The DACs 153R, 153G, and 153B are configured for red, green, and blue colors. By selecting one of the plurality of gamma voltages output from the gamma voltage generator 160, corresponding to the final data, And supplies the analog signal to the display panel 120 as a data signal.

The gamma voltage Vgam corresponding to the most significant bit (MSB) of 8 bits, which is valid data, among 1024 gamma voltages Vgam corresponding to 10 bits generated by the gamma voltage generator 160, The gamma voltage Vgam mapped by the upper level of the gamma voltage generator 160 and corresponding to the least significant bit LSB of the additional data is supplied to the lower level of the gamma voltage generator 160 Even if the additional data is repeatedly inverted in the frame period, the gradation voltage of the valid data, which is the upper bit, is not influenced by the lower bit, so that the flicker problem does not occur.

That is, since the arbitrarily generated additional data corresponds to the gamma voltage Vgam of the low luminance in the vicinity of the critical point, the influence on the entire flicker can be ignored.

The display panel 120 includes a plurality of gate lines GL and a plurality of data lines DL defining a plurality of pixel regions, each of which includes red, green, and blue pixel regions A switching transistor Ts, a driving transistor Td, and light emitting diodes DeR, DeG, and DeB may be formed in red, green, and blue pixel regions, respectively.

The gate driver 121 is connected to a plurality of gate lines GL to apply gate signals and the driver 110 is connected to a plurality of data lines DL to apply a data signal corresponding to the final data, A power supply voltage (PVDD) and a base low voltage (PVEE) are applied to both ends of the light emitting diodes (DeR, DeG, DeB).

The configuration and operation of the gamma voltage generator 160 of the driving circuit 110 will be described in detail with reference to the drawings.

3 is a view illustrating a gamma voltage generator 160 of a driving circuit for automatically adjusting a gray scale voltage using a transfer function according to the first embodiment of the present invention.

3, the gamma voltage generating unit 160 according to the first embodiment of the present invention includes a reference voltage generating unit 161, an amplitude tilt adjusting unit 162, a reference voltage buffer unit 163, And an interpolation section 164.

The reference voltage generating unit 161 generates a plurality of reference resistors Rref connected in series between the high potential power supply voltage VDDH and the low potential power supply voltage VDDL transmitted from the driving power supply generating unit 146 The voltage between the high potential power supply voltage VDDH and the low potential power supply voltage VDDL is distributed by the plurality of reference resistors Rref and is supplied to the plurality of reference voltages Vref from the node between the adjacent reference resistors Rref. Is output.

Here, in order to easily calculate the plurality of reference voltages Vref using the transfer function calculated from the output luminance, the plurality of reference resistors Rref may be configured to have the same resistance value.

The amplitude tilt adjusting unit 162 includes a plurality of MUXs 170 connected to overlap each other at a node of a plurality of reference resistors Rref.

Each of the plurality of muxes 170 has a plurality of input and output channels, wherein the number of the plurality of input channels is less than the number of the plurality of reference resistors Rref, and the plurality of muxes 170 are arranged The number of reference resistors Rref may be greater than or equal to the number of reference resistors Rref assigned to one mux 170.

The plurality of muxes 170 select one of the plurality of reference voltages Vref output from the nodes of the plurality of reference resistors Rref according to the tilt control signal and the amplitude control signal, A plurality of reference resistors Rref for outputting the reference voltage Vref closest to the gradation voltage and slope of the plurality of muxes 170 in descending order or ascending order, Can be selected.

The resistance value corresponding to the threshold voltage is calculated by Equation 3 or Equation 4 according to the magnitude of amplitude when the maximum voltage is determined during the amplitude adjustment and a small difference may occur between the calculated value and the actual value. Lt; RTI ID = 0.0 > 151). ≪ / RTI >

On the other hand, in order to allow each of the plurality of muxes 170 to select one of the plurality of reference voltages Vref output from the nodes of the plurality of reference resistors Rref, For example, the number of the plurality of muxes 170 is preferably equal to or less than the number of the plurality of reference resistors Rref, and may be, for example, a plurality of The number of reference resistors Rref may be a multiple of the number of the plurality of muxes 170 (in particular, an exponential multiple (for example, 2 ^m times and m is a natural number)).

Since the maximum voltage and the minimum voltage of the grayscale voltage graph are selected from the consecutive nodes of the plurality of reference resistors Rref, the first and last muxes of the plurality of muxes 170 are the maximum voltage and the minimum voltage ).

The reference voltage buffer unit 163 includes a plurality of buffers 171 connected to the output channels of the plurality of muxes 170. The plurality of buffers 171 are current amplifiers, And theoretically provides an infinite current to stabilize a plurality of reference voltages Vref which are output voltages.

That is, the plurality of buffers 171 isolate the input impedance to the output impedance at infinite impedance, so that the plurality of reference voltages Vref, which are the outputs of the plurality of muxes 170 due to the load fluctuation at the rear ends of the plurality of muxes 170, The reference voltage buffer unit 163 is connected to the amplitude tilt adjusting unit 162 at the next stage immediately after the amplitude tilt adjusting unit 162. [ Accordingly, the plurality of reference voltages Vref output from the amplitude tilt adjusting unit 162 can be amplified and supplied to the gamma interpolation unit 164 of the subsequent stage in the same voltage source as the gamma reference voltage.

The gamma interpolation unit 164 includes a plurality of gamma resistors Rgam connected between the plurality of buffers 171 of the reference voltage buffer unit 163 and connected in series to each other, A plurality of gamma voltages Vgam are generated using a plurality of reference voltages Vref (gamma reference voltages).

That is, at least one gamma resistor Rgam is connected between a plurality of reference voltages Vref (gamma reference voltages) output from the plurality of buffers 171, and a plurality of reference voltages The reference voltage Vref (gamma reference voltage) is supplied as a voltage source to a node between the plurality of gamma resistors Rgam to output a plurality of gamma voltages Vgam from a node between the plurality of gamma resistors Rgam.

The number of the reference voltages Vref (gamma reference voltages) output from the plurality of buffers 171 is equal to the number of the plurality of muxes 170 and is output from the node between the plurality of gamma resistors Rgam. the number of a plurality of gamma voltages (Vgam) which is equal to the total number of gray levels (2 ⁿ⁾ corresponding to the bit number (n) of the last data.

Here, the total number of gradations (2 ⁿ ) corresponding to the number of bits (n) of the final data is determined by the number of the plurality of muxes 170 and the number of reference voltages Vref Which is equal to or greater than the product of the number of gamma resistors Rgam connected between the reference voltage and the reference voltage.

When the number of bits of the final data (n = a + b) is determined by the sum of the number of input data bits a and the number of additional data bits b of the threshold point compensating unit 151, the number of Rgam) is larger than the gradation number (2 ^a) corresponding to the number of bits (a) of the input data, the number of the plurality of mUX 170 is the number of gradations which corresponds to the bit number (n) of the last data (2 ⁿ ) May be less than or equal to.

For example, when the input data is 8 bits and the final data is 10 bits, the number of the plurality of gamma resistors Rgam may be the number of tones (2 ¹⁰ ) corresponding to the number of bits of the final data, (2 ⁸ ) corresponding to the number of bits of the input data and the gamma resistor Rgam connected between each of the plurality of reference voltages (Vref) output from the plurality of buffers 171 is four (2 ² ).

When the gamma interpolation unit 164 generates a relatively large number of gamma voltages Vgam using a relatively small number of reference voltages Vref, The resistance values of the plurality of gamma resistors Rgam may be set so that the gamma voltages Vgam have the same voltage difference or a plurality of gamma resistors Rgam may be set so that the plurality of gamma voltages Vgam are intermediate voltages corresponding to the slope of the gradation voltage graph Rgam) can be set.

Conventionally, in calculating various slopes of the luminance graph, the resistance values of a plurality of gamma resistances Rgam are set to correspond to a specific panel. In the panel manufactured by the same process, The slope is set to an inaccurate approximate value due to the resistance value of the gamma resistance Rgam, and as a result, it is difficult to realize a luminance graph that exactly matches the measured luminance. In the present invention, however, The uniformity ratio is uniformly adjusted by the plurality of reference resistors Rref having a value such that the plurality of gamma voltages Vgam between the plurality of reference voltages Vref selected by the plurality of muxes 170 also have uniformity .

The number of reference voltages Vref input to the gamma interpolation unit 164 is the same as the number of the plurality of muxes 170 of the amplitude tilt adjusting unit 162. In this case, The grayscale voltage graph has a curve-shaped slope, and the luminance graph of each of red, green, blue, and white colors must maintain a curve at the corresponding halftone.

Therefore, in order that the luminance graph has a curvature or a curve-like slope at all gradations, the number of bits of the input data must be sufficiently increased by using an additional data generation method such as dithering.

Accordingly, the threshold compensating unit 151 generates and adds the additional data to the input data. The threshold compensating unit 151 generates additional data corresponding to the low luminance interval so as not to affect the effective luminance interval and the high luminance interval And at the same time, sufficiently increases the number of bits of the final data.

That is, the gradation voltage in the low-luminance interval corresponding to the critical point with large uncertainty in the luminance measurement and large instability is calculated by using the transfer function, and the additional data is added to repeatedly provide the inverted data only when the valid data exists The grayscale voltage in the middle luminance section and the high luminance section can be maximized by utilizing the effective period of the input data.

The afterimage anti-aging unit 152 inverts the polarity of the input data at a constant cycle.

When an image including a specific pattern such as an image in which the display panel (120 in Fig. 2) is stopped is displayed for a long time, the area corresponding to the specific pattern can be aged faster than the other area, There is a residual image that affects other images, or a difference in usage frequency of red, green, and blue colors causes unevenness in the image, or distortion of the balance of red, green, and blue colors.

In order to prevent this, the frequency of use of all the pixels is substantially equalized by inverting the input data for a short time using the characteristics of a relatively short response time of the self-light emitting display within a range that does not affect the visibility, The period of the reversal can be adjusted in consideration of the improvement of the contrast ratio by the inversion of the whole and the increase of the fatigue by the flicker.

The configuration and operation of the amplitude tilt adjusting unit 162 will be described with reference to the drawings.

FIG. 4 is a diagram showing an amplitude tilt adjusting unit 162 of a driving circuit for automatic adjustment of gradation voltage using a transfer function according to the first embodiment of the present invention. In FIG. 4, the input data corresponding to a video signal is 8 bits, The case where the additional data corresponding to the luminance is 2 bits and the final data to which the additional data is added to the input data is 10 bits will be described as an example.

4, in the driving circuit for automatically adjusting gradation voltages according to the first embodiment of the present invention, the reference voltage generator 161 includes a plurality of reference resistors R0 to R1023 The reference voltage buffer unit 163 includes a reference resistor Rref and the amplitude tilt adjusting unit 162 includes a plurality of muxes 170 composed of 0th to 255th muxes MUX0 to MUX255, And a buffer 171.

The plurality of muxes 170 of the amplitude tilt adjusting unit 162 are configured to have a number less than or equal to the number of tones corresponding to the number of bits of the final data and the gamma resistance Rgam is configured to have an equal interval distribution having the same resistance value. As the number of the muxes 170 approaches a sufficiently large number of effective data bits (for example, 8 bits), the gradation voltage graph can have a curved slope. (= 2 ¹⁰ ) corresponding to the 10-bit final data, the closer to the curved line the more the number of the muxes 170 is used. For example, ¹⁰⁾ a small number of gradation 0 to the 256 than 255 may be configured as a multiplexer (4 gamma resistance (Rgam) connected to between each MUX0 to MUX255) to an adjacent multiplexer.

The plurality of muxes 170 are connected to the plurality of reference voltages Vref output from the reference voltage generator 161 in order to select the reference voltage Vref which is maximally similar to the gradation voltage according to the gradation voltage information. The output voltage of the amplitude tilt adjusting unit 162 is adjusted by adjusting the magnitude of the plurality of reference resistors Rref and the range of selecting the reference voltage is fixed for each position, It is determined as a voltage regulation method for selecting some of the plurality of reference voltages Vref instead.

In the related art, since the resistance is set to correspond to the luminance measured by the manual resistance adjusting method, the accuracy of the gradation voltage adjustment depends on the degree of the preset resistance array corresponding to the measured luminance, and the manual resistance adjustment is determined depending on the situation However, in the present invention, a transfer function factor such as gradation voltage information and slope information is calculated using the transfer function from the measured luminance, and then the correct gradation voltage is calculated by selecting the corresponding gradation voltage, For models with an approximate resistance value and a gamma resistance structure of various driving circuits, it is possible to cope with various types of slopes and amplitudes owing to a large number of muxes and an equipotential resistor arrangement having a sufficiently large number of overlapping resistor setting ranges The gradation voltage can be adjusted as accurately as possible.

At this time, when selecting the gradation voltage corresponding to the transfer function factor such as the gradation voltage information and the slope information, if the gradation voltage is first selected from the portion 170 where the gradation voltages for the adjacent gradations overlap each other, Can not be selected in the entire region of the selectable input reference voltage Vref and the selection period is reduced to the remaining input reference voltage Vref except for the overlapped portion so that the gradation voltage is selected from the muxes 170 that do not overlap each other It is advantageous.

That is, it is normal to proceed with selecting the mux 170 in descending order of the high voltage.

The first and last muxes among the plurality of muxes 170 of the amplitude tilt adjusting unit 162 are portions for determining the amplitude of the grayscale voltage graph by selecting the maximum voltage and the minimum voltage respectively, And determines the slope of the grayscale voltage graph.

On the other hand, the configuration and operation of the critical point compensating unit and the residual image aging preventing unit will be described with reference to the drawings.

FIG. 5 is a diagram showing a critical point compensating unit 151 and a residual image aging preventing unit 152 of a driving circuit for automatic adjustment of gradation voltage using a transfer function according to the first embodiment of the present invention. FIG. 1 is a waveform diagram of signals used in a threshold compensation unit 151 and a residual image anti-aging unit 152 of a driving circuit for automatic adjustment of gradation voltage using a transfer function, in which input data corresponding to a video signal is 8 bits The case where the additional data corresponding to the low brightness which is the critical point is 2 bits and the final data in which the additional data is added to the input data is 10 bits will be described as an example.

5 and 6, in the driving circuit for automatic adjustment of gradation voltage according to the first embodiment of the present invention, the critical point compensating section 151 compensates the zero-th signal DC0 of the two- And the additional signal (QB) of the 4-frame period, which is the 0th signal (DC0) divided into two by the anti-flip flop 172 of the additional data generating unit 155, as the data D0, The data D0 and D1 of the 0th and 1st bits are used as the input data D2 through D0 via the OR gate 176 so that the selected input data of the upper bit can be used only. D5 or D6 to D9 are input to the first and second AND gates 177 and 178, respectively, with the 0th and 1st bits of data DO and D1, respectively.

Then, the afterimage anti-aging unit 152 can select the normal input data and the inverted input data in a desired cycle according to the first signal DC1.

The critical point compensation unit 151 includes an OR gate 176 and first and second AND gates 177 and 178. The residual image anti-aging unit 152 includes a plurality of inverters 173, A plurality of data muxes 174 and a third AND gate 175, and the additional data generating unit 155 includes an anti-flip flop 172.

The additional data generation unit 155 generates the 2-bit additional data to be added to the 8-bit input data. The additional data generation unit 155 outputs the 0-th signal DC0 to the Q-node, By feeding back to the input of the anti-flip flop 172 and dividing the frequency by 2, and using the 0-th signal DC0 having 2 frames as a clock And outputs an additional signal QB with a period of 4 frames to the QB node.

Here, the 0-th signal DC0 is used as the clock of the flip-flop 172. The 2-bit additional data corresponding to the bit difference between the last data of 10 bits and the input data of 8 bits is the gray- (Equation 1) by using the transfer function relationship (Equation 1), thereby avoiding the unstable portion of the grayscale adjacent to the critical point and solving the difficulty of the measurement of the sub-critical luminance.

For example, the additional data may be 2-bit data which totally increases the low brightness gradation which is a critical point. In another embodiment, the number of bits of the additional data can be increased or decreased as needed.

The critical point compensation unit 151 generates 2-bit additional data using the 0-th signal DC0 and the additional signal QB of the additional data generation unit 155 and adds the 2-bit additional data to 8-bit input data. It is possible to generate additional 2-bit additional data.

Here, the critical point compensator 151 detects the 8-bit input data and adds the additional data to the input data only when the valid data exists, thereby avoiding that the additional data is always added to the input data, .

At this time, the upper additional data D1 is generated from the valid data of the upper portions D6 to D9 of the input data detected by the oregate 176, and the lower additional data D0 is generated from the valid data of the upper portions D6 to D9 detected by the oregate 176 From the valid data of the input data lower part (D2 to D5), or by reversely selecting the valid data.
Accordingly, the input data corresponding to the video signal is set as the second to ninth bit data D2 to D9, and the output signal of the critical point compensating unit 151 is divided into the 0th and 1st bit data D0 and D1 ), And the final data of 10 bits is input to the DAC 153.

That is, the valid data, which is the upper bit, is mapped by the upper level of the gamma voltage generator 160, and the additional data which is the lower bit is mapped by the lower level of the gamma voltage generator 160, The problem of the flicker in which the output luminance shakes is prevented.

The plurality of inverters 173 inverts the input data of 8 bits each to invert the input data to prevent a residual image due to a specific pattern and aging. And the inverted signal (DC1) output from the third AND gate 175 having the first signal DC1 as the first input and the second input as the first input signal DC1 for adjusting the inversion period, INV), the plurality of data muxes 174 select one of the 8-bit input data or the inverted 8-bit input data, respectively, and input the data to the DAC 153.

By adjusting the inversion period of the inversion signal INV to a range that does not affect the visibility of the image, it is possible to improve the contrast while preventing or minimizing the lifetime. In the organic light emitting diode display, This is possible because flicker due to short time inversion is not a big problem because it is as short as several tens of microseconds (㎲).

On the other hand, in the large area organic light emitting diode display device, the decrease in the power supply voltage (PVDD) and the base low voltage (PVEE) of the light emitting diode due to the voltage drop (IR-drop) increases from the power supply part, Resulting in a reduction in luminance for the data. Therefore, in the case of a large area display device, the difference between the driving circuits 110 must be compensated. For this purpose, the plurality of driving circuits 110 may share a transfer function factor such as gradation voltage information and slope information.

The operation of the amplitude tilt adjusting section 162 of the driving circuit 110 will be described with reference to the drawings.

7A, 7B and 7C are diagrams illustrating a luminance graph, a gradation voltage graph, and a reference voltage generator used for threshold voltage, amplitude, and maximum voltage adjustment in the driving circuit for automatic adjustment of gradation voltage according to the first embodiment of the present invention to be.

As shown in FIG. 7A, after the RGB pattern is displayed on the display device and the brightness is measured for each site using the luminance meter, the transfer function calculator (180 in FIG. 2) calculates a luminance transfer function corresponding to the luminance transfer function The measured luminance graph can be adjusted to the target luminance graph when the target luminance based on the tristimulus equation of the transfer function calculator 180 is determined by calculating the luminance graph according to the number of gradations, Represents a luminance graph (i.e., a luminance transfer function curve), and a solid line represents a measured luminance graph

That is, the target maximum brightness Y1 and the target threshold brightness Y2 are selected from the measured brightness graphs and the first and second points P1 and P2 corresponding to the target maximum brightness Y1 and the target threshold brightness Y2, respectively, And the third threshold value P3 corresponding to the target intermediate brightness between the target maximum brightness Y1 and the target threshold brightness Y2 are selected as the target maximum brightness Y1 and the target threshold brightness Y2 And the number of gradations of the fourth and fifth points P4 and P5 of the corresponding measured luminance graph are set to the maximum and minimum gradation numbers, respectively, the number of gradations of the sixth point P6 of the measured luminance graph corresponding to the target intermediate luminance, The slope can be calculated.

The number of gradations of all the points between the fourth and fifth points P4 and P5 in a state in which the fourth and fifth points P4 and P5 coincide with the first and second points P1 and P2, The difference between the third and sixth points P3 and P6 is the slope difference between the target luminance and the measured luminance so that this slope difference can be corrected in the voltage transfer function according to the correlation of the transfer function.

As shown in FIG. 7B, the transfer function calculator (180 in FIG. 2) calculates a voltage graph corresponding to the number of gradations corresponding to the voltage transfer function from the luminance graph using the correlation of the transfer function.

Here, when the switching element and the driving element of the voltage transfer function are of the positive type (P type), the correlation of the transfer function is expressed by the slope function (r (x)) of the luminance transfer function and the slope function 1 / kr (x), k is a constant) is in a proportional relationship with the inverse function, and the slope value of the slope function at each gradation x is expressed as r or 1 / r, The maximum value and the threshold value of the luminance are opposite to the maximum value and the threshold value of the luminance.

Although not shown, when the switching elements and the driving elements of the voltage transfer function are of a negative type (N-type), the correlation of the transfer function depends on the slope function r (x) of the luminance transfer function and the slope function kr (x) and k are constants) are proportional to each other. In contrast to FIG. 7B, the maximum value and the threshold of the gray level voltage are located at the same value as the maximum value and the threshold value of luminance.
The transfer function calculator (180 in FIG. 2) calculates a transfer function factor such as gradation voltage information and gradient information from the gradation voltage graph (i.e., the voltage transfer function curve) and transfers it to the drive circuit (110 in FIG. 2) For example, the fourth, fifth and sixth points P4, P5 and P6 of the corrected gradation voltage graph and the fourth, fifth and sixth points P4, P5 and P6 of the luminance transfer function graph can be expressed by the transfer function The critical luminance, and the intermediate luminance, respectively, according to the correlation between the luminance and the luminance.

As shown in Fig. 7C, the driving circuit (110 in Fig. 2) includes a plurality of muxes (170 in Fig. 3) to select the reference voltage Vref closest to the gradation voltages corresponding to the respective gradation numbers in the corrected gradation voltage graph ).

For example, when the gradation voltages of the fourth, fifth and sixth points P4, P5 and P6 representing the maximum luminance, the critical luminance and the intermediate luminance are the fifth, fifth, and eleventh reference voltages V0, V511, V1000), a plurality of muxes (170 in Fig. 3) can be controlled to select the output voltage of the node connected to the fifth, fifth, and ninth reference resistors R5, R511, and R1000, respectively.

The gradation voltage automatic adjustment operation using the transfer function will be described with reference to the drawings.

8A is a diagram illustrating a voltage transfer function and a luminance transfer function used in a driving circuit for automatic adjustment of gradation voltage using a transfer function according to the first embodiment of the present invention. And the gradation voltage automatic adjustment result by the driving circuit for automatically controlling the gradation voltage using the transfer function is programmed.

As shown in FIG. 8A, in order to adjust the white balance and the white maximum luminance to the target value, information of the intrinsic color coordinate values of the red, green, and blue materials is secured, and red, green and blue colors are obtained using a tristimulus calculation method. The luminance of the blue color is determined and the target luminance graph corresponding to the number of gradations is calculated.

Here, the luminance transfer function of the luminance graph can be expressed by a slope function r (x) such that Y = A * (x / dx) ^{r (x)} + B, where Y represents the luminance of the organic light emitting diode, R denotes the slope function of the luminance transfer function (tangent of the tangent line at each gradation number of the luminance transfer function curve), r (x) denotes the slope function of the luminance transfer function R represents the slope at the corresponding gradation x, x represents the number of gradations, and dx represents the total number of gradations.

Then, the voltage transfer function is calculated from the luminance transfer function using the inverse correlation between the luminance transfer function and the slope of the voltage transfer function, and a grayscale voltage graph corresponding to the number of grayscales is calculated.

Here, the voltage transfer function of the gradation voltage graph can be expressed by y = V- (a * (x / dx) ^{1 / kr (x)} + b), where y represents the gradation voltage of the driving circuit, Represents a difference (VDDH-VDDL) between the high-potential reference voltage VDDH and the low-potential reference voltage VDDL as a total gradation voltage of the voltage transfer function, a represents the amplitude of the voltage transfer function, 1 / kr (x) represents the slope function of the voltage transfer function (the slope of the tangent line at each gradation of the voltage transfer function curve, where k is a proportional constant), and 1 / r Represents the slope value at the corresponding gradation x, x represents the number of gradations, and dx represents the total number of gradations.

8B, the transfer function arithmetic unit 180 may be realized by software such as an application programming interface (API) computing engine of a computer. The transfer function arithmetic unit 180 may adjust the intrinsic color coordinate values of the red, And the white coordinate is calculated to display the result of the change.

That is, the red, green, blue, and white luminance curves calculated from the measured luminance are calculated, and the red, green, blue, and white luminance curves are plotted using the correlation between the luminance transfer function and the voltage transfer function. The values of the voltage transfer functions of the red, green, blue, and blue voltages of the red, green, blue, and white voltage curves are calculated as a transfer function factor such as gradation voltage information and tilt information, 110).

2) of the gamma voltage generator (160 in FIG. 2) according to the transfer function factor of the gradation voltage information and the gradient information, 2) of the gamma voltage generator 160 (FIG. 2) by selecting a node of a plurality of reference resistors (Rref in FIG. 2) that outputs the voltage closest to the value of the voltage transfer function by controlling the gamma interpolation unit 2), the adjusted gradation voltage is automatically outputted, and the adjusted gradation voltage is stored in the gradation resistance memory.

In this case, the voltage drop due to the resistance (IR-drop) may occur not only in the region but also in the red, green, and blue separate driving and red, green, and blue driving for white display.

That is, since the resistances at the red, green, and blue separate driving are different from the resistances at the red, green, and blue driving simultaneously, the sum of the 256 gray scales of the white and the 256 gray scale voltages of red, For example, the gray scale voltage of 256 gray scales of white may be smaller than the sum of gray scale voltages of 256 gray scales of red, green, and blue.

Therefore, when adjusting the gradation voltage automatically, not only the red, green and blue balance but also the white balance should be considered.

In the first embodiment of the present invention, the gradation voltage is automatically adjusted by using the same transfer function without dividing the display panel. In another embodiment, the display panel is divided into a plurality of blocks, It is also possible to automatically adjust the voltage, which will be described with reference to the drawings.

FIG. 9 is a diagram illustrating a display device including a driving circuit for automatically adjusting a gray scale voltage using a transfer function according to a second embodiment of the present invention.

9, the display device according to the second embodiment of the present invention includes a display panel 220 for displaying an image, a luminance meter 282 for measuring the luminance of an image displayed on the display panel 220 And a transfer function calculator 282 which receives the measured luminance information from the luminance meter 282 and calculates a transfer function factor such as gradation voltage information and gradient information from the luminance information using the transfer function, A signal processing center 281 for converting the gradation voltage information and the initial code into digital signals and transmitting them to the first and second driving circuits 210a and 210b and supplying a plurality of power sources, And first and second driving circuits 210a and 210b that generate gradation voltages that are automatically adjusted using a transfer function factor such as a tilt.

The display panel 220 includes a display area divided into first to fourth blocks and first and second gate drivers 221a and 221b. The first gate driver 221a is connected to the first and third blocks The second gate driver 221b applies a gate signal to the second and fourth blocks, the first driver circuit 210a applies a data signal to the first and second blocks, The driving circuit 210b applies the data signal to the third and fourth blocks.

Four luminance meters 282 may be provided to correspond to the first to fourth blocks of the display panel 220. In another embodiment, one luminance meter may be used for each block.

Then, the signal processing center 281 may manage the input / output of the sample in the automation system.

The first driving circuit 210a includes a first color balance processor 236a, a first gradation voltage memory 256a, a first synchronizing signal counter 283a, and first and second gamma voltage generators 260a and 260b And the second driving circuit 210b includes a second color balance processor 236b, a second gradation voltage memory 256b, a second synchronous signal counter 283b, and third and fourth gamma voltage generators 260c , 260d.

Here, the first and second color balance processing units 236a and 236b may have the same configuration and function as those of the color balance processing unit 136 of the first embodiment.

The first and second synchronous signal counters 283a and 283b count the peak value of the signal such as the gate start signal GSP to grasp the number of the gate wiring and identify the corresponding block of the display panel from the number of the gate wiring And the first and second driving circuits 210a and 210b generate a block selection signal corresponding to the selected one of the first and second gamma voltage generators 260a and 260b, 4 gamma voltage generating units 260c and 260d to generate a gamma voltage.

That is, the first driving circuit 210a outputs the data signal generated using the gamma voltage of the first gamma voltage generator 260a to the first block in accordance with the block selection signal of the first synchronous signal counter 283a Or applies the data signal generated by using the gamma voltage of the second gamma voltage generator 260b to the second block.

The second driving circuit 210b outputs the data signal generated by using the gamma voltage of the third gamma voltage generator 260c to the third block in accordance with the block selection signal of the second synchronization signal counter 283b Or applies a data signal generated by using the gamma voltage of the fourth gamma voltage generator 260d to the fourth block.

In this case, in order to minimize the difference in the image quality of each block and the boundary line, the minimum value among the maximum luminance values of the first to fourth blocks is calculated, the maximum luminance value in each block is decreased to the calculated minimum value, The maximum brightness, critical brightness, amplitude (= maximum brightness-critical brightness), and slope can be calculated by calculating the maximum value of the critical brightness and increasing the critical brightness in each block to the calculated maximum value.

In the adjustment of the characteristic for each block, the same input data is simultaneously supplied to the first to fourth blocks to measure the luminance. The variation of each block is adjusted by a slope processing unit (140 in FIG. 2), an amplitude processing unit (142 in Fig. 2), and a critical point correction unit (143 in Fig. 2).

For example, the overall slope maintenance and management is performed by a slope processing unit (140 in FIG. 2) of the first and second driving circuits 210a and 210b, and the minimum value calculation of the maximum luminance of each block is performed by the first and second driving circuits The amplitude processing section (141 in FIG. 2) of the first and second driving circuits 210a and 210b performs the control and correction of the gradation voltage gradient and the luminance gradient in the first and second driving circuits 210a and 210b 2) of the first and second driving circuits 210a and 210b, and the adjustment of the period of the inverse signal of each block is performed by the first And the residual image aging processing section (144 in FIG. 2) of the second driving circuits 210a and 210b are performed by the first and second driving circuits 210a and 210b, and the maximum luminance readjustment and the tilt maintenance by the entire brightness adjustment by the user adjustment are performed by the first and second driving circuits 210a , And 210b (145 of FIG. 2).

The configuration and operation of the first and second gamma voltage generators 260a and 260b of the first driving circuit 210a (the third and fourth gamma voltage generators 260c and 260c of the second driving circuit 210b, 260d) will be described in more detail with reference to the drawings.

FIG. 10 is a diagram showing first and second amplitude tilt adjusting units 262a and 262b of the driving circuit for automatically controlling the gray level voltage using the transfer function according to the second embodiment of the present invention, and FIG. And the first and second gamma interpolation sections 264a and 264b of the driving circuit for automatically controlling the gradation voltage using the transfer function according to the second embodiment.

As shown in FIGS. 10 and 11, the first and second gamma voltage generators 260a and 260b according to the second exemplary embodiment of the present invention include a reference voltage generator 261, first and second amplitudes Tilt adjusting units 262a and 262b, first and second reference voltage buffer units 263a and 263b, and first and second gamma interpolation units 264a and 264b.

The first and second gamma voltage generators 260a and 260b may be configured to share the reference voltage generator 261. The first gamma voltage generator 260a may include a reference voltage generator 261, The second gamma voltage generating unit 260b includes a reference voltage generating unit 261, a first reference voltage generating unit 262, a first reference voltage generating unit 263, a first reference voltage generating unit 263, A second amplitude slope adjusting unit 262b, a second reference voltage buffer unit 263b, and a second gamma interpolation unit 264b.

The first amplitude tilt adjusting unit 262a includes a plurality of first muxes 270a and the second amplitude tilt adjusting unit 262b includes a plurality of second muxes 270b and includes a reference voltage generating unit 261, The configurations and functions of the first and second reference voltage buffer units 263a and 263b and the first and second gamma interpolation units 264a and 264b may be the same as those of the first embodiment.

The first color balance processing unit 236a receives a plurality of first reference voltages Vref1 (V0 to V255) from the first gamma voltage generating unit 260a in accordance with a block selection signal transmitted from the first synchronous signal counter 283a And outputs a plurality of second reference voltages Vref2 (U0 to U255) from the second gamma voltage generator 260b. The first DAC 253a includes a first threshold compensator 251a, (10 bits) and the first reference voltage (Vref1) (V0 to V255) through the residual image anti-aging unit 252a and the first block selection unit 255a, And the second DAC 253b generates a data signal to be applied to the block through the first threshold compensating unit 251a, the first afterimage anti-aging unit 252a and the first block selecting unit 255a, And a plurality of second reference voltages Vref2 (U0 to U255) to generate a data signal to be applied to the second block of the display panel 220. [

Although not shown, the second color balance processor 236b may be configured to output a plurality of third reference voltages from the third gamma voltage generator 260c according to a block selection signal transmitted from the second sync signal counter 283b, A plurality of fourth reference voltages are output from the fourth gamma voltage generating unit 260d, and the third DAC receives final data (10 bits) through the second threshold compensating unit, the second afterimage anti-aging unit, and the first block selecting unit And generates a data signal to be applied to the third block of the display panel 220 by using a plurality of third reference voltages, and the fourth DAC generates a data signal by using the second threshold compensating unit, the second afterimage anti- And generates a data signal applied to a fourth block of the display panel 220 using data (10 bits) and a plurality of fourth reference voltages.
On the other hand, in another embodiment, when each of the driving circuits is connected to a plurality of blocks of one column or one row of the display panel, a plurality of gamma voltage generating units of the color balance processing unit of the driving circuit A plurality of blocks may correspond to each other on a one-to-one basis, or a plurality of gamma voltage generators may be selectively connected to a plurality of blocks to adjust connected blocks.
At this time, the driving circuit includes at least two gamma voltage generators, and each gamma voltage generator may be connected to at least two blocks.

The configuration and operation of the block selector of the driving circuit for automatic adjustment of gradation voltage using the transfer function according to the second embodiment of the present invention will be described with reference to the drawings.

FIG. 12 is a block diagram illustrating a first threshold value compensating unit 251a, a first afterimage anti-aging unit 252a, and a first block selecting unit 255a of a driving circuit for automatic adjustment of gradation voltage using a transfer function according to the second embodiment of the present invention. In which the input data corresponding to the video signal is 8 bits, the additional data corresponding to the low brightness, which is the threshold, is 2 bits, and the final data in which the additional data is added to the input data is 10 bits, as an example Explain.

12, in the driving circuit for automatic adjustment of gradation voltage according to the second embodiment of the present invention, the first threshold compensating section 251a includes an OR gate 276, first and second end AND gates 277 and 278. The first afterimage anti-aging section 252a includes a plurality of inverters 273, a plurality of data muxes 274, and a third AND gate 275, The generating unit 255 includes an anti-flip flop 272, and the first block selecting unit 255a includes a plurality of block muxes 276. [

The configurations and functions of the first threshold-point compensating section 251a, the first afterimage anti-aging section 252a, and the additional data generating section 255 may be the same as those of the first embodiment.

The first block selector 255a selects the output of the first residual anti-aging unit 252a based on the block selection signal of the first synchronizing signal counter 283a to the first DAC 253a or the second block 253a corresponding to the first block, The first driving circuit 210a applies a data signal generated by the first DAC 253a to the first block and the second DAC 253b is applied to the second block by the first driving circuit 210a, Lt; / RTI >

At this time, in order to prevent the shaking of the gradation voltage at the time of block change, the reference voltage is provided to all the blocks at the same time, and when the gate line is driven, the first block selector 255a selects the block- , And 253b in accordance with the DAC change method.

In the driving circuit for automatic adjustment of gradation voltage using the transfer function according to the second embodiment of the present invention, the gradation voltage is automatically adjusted by using the voltage transfer function, so that the white balance is maintained and the visual uniformity The total luminance can be increased or decreased according to the surroundings or the user's selection. The dimming adjustment method will be described with reference to the drawings.

FIG. 13A is a diagram illustrating a voltage transfer function and a luminance transfer function used in a driving circuit for automatic adjustment of gradation voltage using a transfer function according to a second exemplary embodiment of the present invention. FIG. FIG. 13C is a view illustrating a driving power supply generating unit of the driving circuit for automatically adjusting the gray level voltage using the transfer function according to the second embodiment of the present invention .

As shown in FIG. 13A, the luminance transfer function and the voltage transfer function have a reciprocal correlation with each other. When the total luminance is reduced by dimming adjustment, the red, green, and blue luminance transfer functions are shifted to the same gray scale ratio The back balance is maintained, the visual uniformity is maintained for each luminance increment and decrement, and the luminance and gradation voltages are calculated by the voltage transfer function in association with the transfer function.

A push signal is output from a push button 255 of the dimming adjustment unit 245 and an up down counter 286 increases or decreases the number of gradations according to the push signal, At this time, the dimming adjustment unit 245 calculates the gradation voltage corresponding to the increase / decrease of the number of gradations by using the voltage transfer function.

That is, when the bias voltage V is applied from the voltage transfer function, the ratio of the gradation voltage yx to the number of gradations x with respect to the gradation voltage y1023 of the maximum gradation number can be calculated, and the gradation voltage ratio yx / y 1023 are kept constant even when the bias voltage V is changed from the high potential reference voltage VDDH to the logic power supply voltage VCC so that the gradation voltage (yx) can be calculated.

Therefore, the gradation voltage yx for the x-gradation number calculated by the voltage transfer function corresponds to the case where the bias voltage V is the high-potential reference voltage VDDH. Therefore, The driving voltage generator (for example, a PWM IC) can be physically adjusted by changing the upper reference voltage VDDH.

However, when the high-potential power supply voltage VDDH is used as the bias voltage V for dimming in the same manner as the voltage transfer function, since the high-potential power supply voltage VDDH of the voltage transfer function is changed by the dimming adjustment, In this case, the logic power supply voltage (VCC) used for the entire driving circuit is used as the voltage of the power transfer function for dimming, and the relationship between the two voltage transfer functions It keeps.

The dimming voltage y calculated in FIG. 13B is converted into a PWM (PWM) voltage by using the logic power supply voltage VCC equal to the bias voltage V for dimming as the reference reference voltage of the PWM IC which is the generation portion of the high- It can be increased or decreased by high reference voltage or low potential voltage by dimming stage by reference reference voltage of IC.

For example, as shown in FIG. 13B, the logic power supply voltage VCC may be used as the overall voltage, and the voltage may be output as the dimming voltage y by the step increased or decreased by the push button 255.

13C, in order to apply the increased and decreased gradation voltage information with respect to the high-potential reference voltage VDDH to the transistor power supply voltage VCC, the driving power supply generating section 246 converts the gradation voltage into a resistance value A plurality of power supply resistors Rv0 to Rv1023 292 connected in series between the transistor power supply voltage VCC and the ground voltage GND and a plurality of power supply resistors Rv0 to Rv1023, And a power supply unit 295 connected between the high potential power supply voltage VDDH and the low potential power supply voltage VDDL.

Thus, the voltage resistance conversion section 291 supplies the increased and decreased gradation voltages to the node between the plurality of power resistances 292, and the power mux 293 supplies a plurality of power resistances 292 in accordance with the increased and decreased gradation voltage information. To the power supply unit 295, and the power supply unit 295 adjusts the output voltage according to the increased / decreased gray-level voltage information.

Such a configuration is formed in the driving circuit to generate a relatively increased or decreased gradation voltage with the same transistor power supply voltage (VCC) as that of the external system as a reference voltage. However, such a configuration may be formed outside the driving circuit to exhibit the same function , And applying the result to one of the red, green, and blue transfer functions can be applied to the high potential power supply voltage (VDDH) to increase or decrease the same ratio.

Meanwhile, in another embodiment, the fixed voltage generator may be formed at the front end of the reference voltage generator to improve the slope of the automatic adjustment characteristic, which will be described with reference to the drawings.

FIG. 14 is a view illustrating a driving circuit for automatic adjustment of gradation voltage using a transfer function according to the third embodiment of the present invention.

14, the gradation voltage automatic adjustment driving circuit 310 using the transfer function according to the third exemplary embodiment of the present invention includes a fixed voltage generation unit 395, a gradient amplitude linear adjustment unit 396, And a generating unit 361.

The configuration of the latter stage of the reference voltage generator 361 is the same as that of the first embodiment, and a description thereof will be omitted.

The fixed voltage generator 395 includes a plurality of fixed resistors Rv0 to Rv1023 connected in series between a high potential power supply voltage VDDH and a low potential power supply voltage VDDL, The voltage between the low potential power supply voltage VDDL is distributed by the plurality of fixed resistors Rv0 to Rv1023 and a plurality of fixed voltages Vf are output from the node between the adjacent fixed resistors Rv0 to Rv1023.

The amplitude slope linear regulating unit 396 includes a plurality of fixed muxes 397 connected to overlap each other at a node between the plurality of fixed resistors Rv0 to Rv1023, Rv 1023 to one of the nodes between the plurality of reference resistors Rref of the reference voltage generator 361. [

In the third embodiment, the overall slope of the transfer function is adjusted in advance by the fixed voltage generation unit 395 and the amplitude gradient linear adjustment unit 396 so that the reference voltage generation unit 361 and the slope amplitude adjustment unit (not shown) Configuration and operation are simplified.

That is, by providing a plurality of reference power supply voltages other than the high potential power supply voltage VDDH and the low potential power supply voltage VDDL to the plurality of reference resistors Rref, the plurality of reference resistors Rref ) Are formed in various forms, and the plurality of reference voltages output from the plurality of reference resistors Rref have different intervals, and as a result, the number of the plurality of muxes of the gamma voltage generator can be reduced.

In this case, the grayscale voltage graph may partially have a linear slope in accordance with the decrease of the number of the muxes. By controlling the size of the plurality of gamma resistances Rgam of the gamma interpolation unit at the rear stage, .

A buffer is omitted between the fixed voltage generator 395 and the reference voltage generator 361. Since a buffer is formed between the reference voltage generator 361 and the gamma interpolator (not shown), the impedance change of the DAC And the voltage adjustment method for changing the voltage is used instead of the resistance adjustment method for changing the resistance for adjusting the gradation voltage, so that the impedance change does not affect the gradation voltage adjustment.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention as defined in the appended claims. It can be understood that

110: drive circuit 120: display device
130: Transfer Function Operation Unit 136: Color Balance Processing Unit
160: gamma voltage generator

Claims (20)

A transfer function arithmetic unit for calculating the gradation voltage information and the slope information from the luminance of the image using the transfer function;
A color balance processor receiving the gradation voltage information and the slope information;
A gamma voltage generating unit for generating a plurality of gamma voltages under the control of the color balance processor,
Lt; / RTI >
Wherein the gamma voltage generator comprises:
A reference voltage generating unit comprising a plurality of reference resistors connected in series between a high potential power supply voltage and a low potential power supply voltage;
An amplitude tilt adjusting unit including a plurality of muxes connected to overlap the nodes between the plurality of reference resistors;
And a plurality of gamma resistors connected to the plurality of muxes,
A driving circuit for automatic adjustment of gradation voltage using a transfer function including a transfer function.
The method according to claim 1,
And the plurality of reference resistors are used for automatically adjusting the gradation voltage using transfer functions having the same resistance value.
The method according to claim 1,
Wherein the number of the plurality of muxes is less than or equal to the number of the reference resistors.
The method of claim 3,
Wherein the number of reference resistors is 2 ^m times (m is a natural number) times the number of the plurality of muxes.
The method according to claim 1,
Wherein the total number of gradations corresponding to the number of bits of the final data used for the display of the image is the sum of the number of the plurality of muxes connected to each of the plurality of reference voltages outputted from the plurality of muxes A driving circuit for automatic adjustment of gradation voltage using a transfer function such as the product of the number.
The method according to claim 1,
And the plurality of gamma resistors are used for automatically adjusting the gradation voltage using a transfer function having the same resistance value.
The method according to claim 1,
Wherein the gamma voltage generator comprises:
A fixed voltage generator comprising a plurality of fixed resistors connected in series between the high potential power supply voltage and the low potential power supply voltage;
And a plurality of fixed muxes connected to the nodes between the plurality of fixed resistors so as to overlap with each other,
Further comprising:
And a plurality of fixed voltages output from the plurality of fixed muxes are supplied to nodes between the plurality of reference resistors.
The method according to claim 1,
A threshold point compensating unit for generating additional data and adding it to input data used for displaying the image to generate final data;
The driving circuit for automatic adjustment of the gradation voltage using the transfer function further includes:
9. The method of claim 8,
Wherein the input data and the additional data correspond to upper and lower bits of the final data, respectively, and the additional data is generated only when the input data is valid.
9. The method of claim 8,
And the additional data is mapped by a lower level of the gamma voltage generator.
9. The method of claim 8,
And a residual anti-aging preventing unit for inverting the polarity of the input data according to a preset inversion period.
The method according to claim 1,
Wherein the transfer function calculating unit is configured in an arithmetic unit outside the color balance processing unit, or is a driving circuit for automatically adjusting a gray level voltage using a transfer function integrated in the color balance processing unit.
The method according to claim 1,
The transfer function calculator may include:
A tilt processor for generating a tilt control signal according to the tilt information and transmitting the tilt control signal to the color balance processor;
An amplitude controller for generating an amplitude control signal according to the maximum voltage information of the gradation voltage information and transmitting the amplitude control signal to the color balance processor;
A gamma calculator for generating a gamma control signal according to the tilt information and transmitting the gamma control signal to the color balance processor;
A critical point correcting unit for generating a critical point control signal for generating additional data and transmitting the critical point control signal to the color balance processing unit;
A residual anti-aging processor for generating a residual anti-aging control signal for polarity reversal of input data and transmitting the generated residual anti-aging control signal to the color balance processor;
A dimming control unit for generating a dimming control signal for reducing the luminance according to the dimming information and transmitting the dimming control signal to the color balance processor,
A driving circuit for automatic adjustment of gradation voltage using a transfer function including a transfer function.
The method according to claim 1,
The transfer function calculator calculates the transfer function y = V- (a *) by using the following equation: Y = A * (x / dx) ^r + B, Y is luminance, x is number of gradations, dx is total number of gradations) (x / dx) ^{1 / r} + b), y is the gradation voltage, V is the total gradation voltage, x is the number of gradations and dx is the total number of gradations) (t), the slope efficiency transfer factor (r, 1 / r) and the threshold point efficiency transfer factor (B, b) so that the luminance transfer function and the voltage transfer function coincide with each other, A driving circuit for automatic adjustment of gradation voltage using a transfer function.
15. The method of claim 14,
When the luminance transfer function passes the minimum luminance point (n0, L0), the intermediate luminance point (n1, L1) and the maximum luminance point (n2, L2), the correlation between the luminance transfer function and the voltage transfer function The intermediate luminance L1 and the maximum luminance L2 corresponding to the minimum luminance point, the intermediate luminance point and the maximum luminance point, the threshold voltage V0, the intermediate voltage V1, (V2) is (L1-L0) / (L2 -L0) = (V0-V1) r / (V0-V2) satisfying ^r, and the threshold voltage (V0) is V0 = V2 + [(V1- V2) / The driving circuit for automatic adjustment of gray level voltage using a transfer function calculated from {1 - ((L1-L0) / (L2-L0)) ^{1 / r} }
A transfer function arithmetic unit for calculating the gradation voltage information and the slope information from the luminance of the image of the first and second blocks of the display panel using the transfer function;
A color balance processor receiving the gradation voltage information and the slope information;
A first and a second gamma voltage generating unit for generating a plurality of first and second gamma voltages under the control of the color balance processing unit,
Lt; / RTI >
Wherein the first gamma voltage generator comprises:
A reference voltage generating unit comprising a plurality of reference resistors connected in series between a high potential power supply voltage and a low potential power supply voltage;
A first amplitude tilt adjusting unit including a plurality of first muxes connected to overlap each other at nodes between the plurality of reference resistors;
And a first gamma interpolation part composed of a plurality of first gamma resistors connected to the plurality of first muxes,
Lt; / RTI >
Wherein the second gamma voltage generator comprises:
A reference voltage generator;
A second amplitude tilt adjusting unit including a plurality of second muxes connected to overlap the nodes between the plurality of reference resistors;
And a second gamma interpolation unit comprising a plurality of second gamma resistors connected to the plurality of second muxes,
Lt; / RTI >
Wherein the plurality of first gamma voltages of the first gamma voltage generator are applied to the first block and the plurality of second gamma voltages of the second gamma voltage generator are applied to the second block using a grayscale voltage Driver circuit for automatic adjustment.
A display panel for displaying an image;
A driving circuit for supplying a data signal to the display panel,
A transfer function arithmetic unit for calculating the gradation voltage information and the slope information from the luminance of the image using a transfer function;
A color balance processor receiving the gradation voltage information and the slope information;
A gamma voltage generating unit for generating a plurality of gamma voltages under the control of the color balance processor,
A driving circuit
Lt; / RTI >
Wherein the gamma voltage generator comprises:
A reference voltage generating unit comprising a plurality of reference resistors connected in series between a high potential power supply voltage and a low potential power supply voltage;
An amplitude tilt adjusting unit including a plurality of muxes connected to overlap the nodes between the plurality of reference resistors;
And a plurality of gamma resistors connected to the plurality of muxes,
.
A display panel divided into first to fourth blocks and displaying an image;
A luminance meter for measuring luminance of the image of the first to fourth blocks;
A first driving circuit for supplying a data signal to first and second blocks of the display panel,
A transfer function arithmetic unit for calculating the gradation voltage information and the slope information from the luminance of the image using a transfer function;
A first color balance processor receiving the gradation voltage information and the slope information;
A first and a second gamma voltage generating unit for generating a plurality of first and second gamma voltages under the control of the first color balance processing unit,
A first driving circuit comprising:
A second driving circuit for supplying the data signal to the third and fourth blocks of the display panel,
The transfer function calculator;
A second color balance processor receiving the gradation voltage information and the slope information;
And third and fourth gamma voltage generators for generating a plurality of third and fourth gamma voltages under the control of the second color balance processor,
A second driving circuit comprising:
A signal processing center for converting the gradation voltage information and initial code into a digital signal and transmitting the digital signal to the first and second driving circuits,
.
19. The method of claim 18,
Wherein the first gamma voltage generator comprises:
A first reference voltage generating unit comprising a plurality of first reference resistors connected in series between a high potential power supply voltage and a low potential power supply voltage;
A first amplitude tilt adjusting unit including a plurality of first muxes connected to nodes between the plurality of first reference resistors to overlap each other;
And a first gamma interpolation part composed of a plurality of first gamma resistors connected to the plurality of first muxes,
Lt; / RTI >
Wherein the second gamma voltage generator comprises:
A first reference voltage generator;
A second amplitude tilt adjusting unit including a plurality of second muxes connected to overlap each other at a node between the plurality of first reference resistors;
And a second gamma interpolation unit comprising a plurality of second gamma resistors connected to the plurality of second muxes,
Lt; / RTI >
Wherein the third gamma voltage generator comprises:
A second reference voltage generator comprising a plurality of second reference resistors connected in series between the high potential power supply voltage and the low potential power supply voltage;
A third amplitude tilt adjusting unit including a plurality of third muxes connected to overlap each other at a node between the plurality of second reference resistors;
And a third gamma interpolation unit including a plurality of third gamma resistors connected to the plurality of third muxes,
Lt; / RTI >
Wherein the fourth gamma voltage generator comprises:
A second reference voltage generator;
A fourth amplitude tilt adjusting unit including a plurality of fourth muxes connected to overlap each other at a node between the plurality of second reference resistors;
And a fourth gamma interpolation unit comprising a plurality of fourth gamma resistors connected to the plurality of fourth muxes,
Lt; / RTI >
The plurality of first gamma voltages of the first gamma voltage generator are applied to the first block, the plurality of second gamma voltages of the second gamma voltage generator are applied to the second block, Wherein the plurality of third gamma voltages of the generator are applied to the third block and a plurality of fourth gamma voltages of the fourth gamma voltage generator are applied to the fourth block.
19. The method of claim 18,
Wherein the transfer function calculating unit calculates the minimum luminance among the maximum luminance of the first to fourth blocks and reduces the maximum luminance in the first to fourth blocks to the calculated minimum luminance value, And the threshold voltage of the first to fourth blocks is increased to the calculated threshold luminance maximum value to calculate the gradation voltage information and the slope information.

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