TWI596586B - Display device, apparatus for generating gamma voltage, and method for the same - Google Patents

Description

Display device, device for generating gamma voltage, and method thereof

Embodiments relate to a display device, a gamma voltage generating device, and a gamma voltage generating method. The embodiment particularly relates to a display device, a gamma voltage generating device, and a gamma voltage generating method for maintaining brightness equally in the process of determining a gamma voltage and after manufacturing a product.

In the manufacturing process of the display device, in order to improve the image quality of the display device, a process of predetermining a gamma voltage is required. The process of predetermining the gamma voltage is a process of predetermining the gamma voltage of each gray level so that the brightness according to each gray level becomes a 2.2 gamma curve. In general, the 2.2 gamma curve has the brightness characteristics best recognized by the human eye.

The test device is connected to the display panel during the process of predetermining the gamma voltage. Furthermore, the ELVDD voltage is supplied to the display panel via the DC/DC converter of the test equipment, and the gamma voltage of the full gray scale according to the brightness of each gray scale of 2.2 gamma curve.

In the completed product state after the manufacturing process of the display device, the ELVDD voltage is supplied to the display panel via a DC/DC converter provided in the display device.

However, a deviation may occur between the output of the DC/DC converter in the process of predetermining the gamma voltage and the output of the DC/DC converter provided in the display device. In addition, in advance The resistance of the connector for connecting the display panel during the process of setting the gamma voltage and the resistance of the test device and the connector actually used for the display device may be different from each other. Therefore, a deviation may occur between the ELVDD voltage supplied to the display panel in the process of determining the gamma voltage in advance and the ELVDD voltage supplied to the display panel in the display device.

In other words, the brightness after the product is manufactured cannot be maintained in the same manner as the brightness of the process of determining the gamma voltage in advance. This causes deterioration in the image quality characteristics of the display device.

The above information disclosed in the prior art is only used to enhance the understanding of the prior art of the present invention, and thus may contain information that does not constitute prior art known to those of ordinary skill in the art to which the present invention pertains.

The embodiment provides a display device, a gamma voltage generating device, and a gamma voltage generating method to equally maintain the brightness in the process of determining the gamma voltage and the brightness after manufacturing the product.

A display device according to an embodiment includes a display unit having a plurality of pixels connecting a plurality of data lines; selecting a gray scale voltage from a plurality of gamma voltages according to the image data to apply the gray scale voltage to the plurality of data lines a data driver; a gamma voltage generator that generates a plurality of gamma voltages; and a first reference voltage generator that generates a reference voltage to generate a plurality of gamma voltages that drive the plurality of pixels in cooperation with the power supply voltage.

The first reference voltage generator can record the voltage difference between the power supply voltage and the first reference voltage in the process of predetermining the gamma voltage, and can generate the second reference voltage as the second power supply voltage and the recorded voltage difference Difference.

The first reference voltage generator may include: the voltage difference generator includes a plurality of resistors coupled in series between the comparison voltage and the ground voltage; and a plurality of distribution powers distributed to the plurality of resistors a voltage difference selecting unit that selects and outputs a voltage corresponding to a voltage difference between the first power source voltage and the first reference voltage, and a difference between the output second power source voltage and a voltage output by the voltage difference selecting unit as a second Reference voltage output unit of reference voltage.

The plurality of resistors included in the voltage difference generator may have a resistance determined by determining a cell distribution for a plurality of distribution voltages.

The voltage difference selecting unit may record a voltage difference between the first power source voltage and the first reference voltage in a process of predetermining the gamma voltage, and may output the recorded voltage difference to the reference voltage output unit after manufacturing the product.

The reference voltage output unit may include a differential amplifier that outputs a difference between a power supply voltage supplied from the outside and a voltage output from the voltage difference selection unit.

The gamma voltage generator may include: a reference voltage dividing unit including a plurality of resistors coupled in series between the reference voltage and the reference voltage; and correspondingly determining gray by using a plurality of distribution voltages distributed to the plurality of resistors a gamma voltage selection unit of a plurality of gamma voltages; and a plurality of gamma corresponding to the full gray scale by using a reference voltage provided by the reference voltage generator and a plurality of gamma voltages selected from the gamma voltage selection unit The gamma voltage output unit of the voltage.

The gamma voltage selection unit may include a first selector that selects a second gamma voltage that represents a gray level higher than a first gamma voltage of the corresponding reference voltage.

The gamma voltage selection unit may further include a second selector that selects the seventh gamma voltage as the lowest of the plurality of gamma voltages corresponding to the full gray scale.

The gamma voltage selection unit may further include a sixth selection of the sixth gamma voltage by using a distribution resistor connecting the second gamma voltage transmitted by the first selector and the seventh gamma voltage selected by the second selector. Selector.

The gamma voltage selection unit may further include a fifth of selecting the fifth gamma voltage by using a distribution resistor connecting the second gamma voltage transmitted by the first selector and the sixth gamma voltage selected by the sixth selector. Selector.

The gamma voltage selecting unit may further include: selecting the fourth gamma voltage by using a distributed resistor that connects the second gamma voltage transmitted by the first selector and the fifth gamma voltage selected by the fifth selector Selector.

The gamma voltage selecting unit may further include: selecting the third gamma voltage by using a distributed resistor that connects the second gamma voltage transmitted by the first selector and the fourth gamma voltage selected by the fourth selector Selector.

The gamma voltage generator may further include the microcontroller providing the recorded value to control the gamma voltage to the gamma voltage selection unit in minutes.

A second reference voltage generator that generates a reference voltage to generate a plurality of gamma voltages that drive a plurality of pixels in conjunction with a supply voltage is further included.

The second reference voltage generator can record the voltage difference between the first power voltage and the first reference voltage in the process of determining the gamma voltage, and can generate the second reference voltage as the second power voltage and the recorded voltage difference The difference between the two.

The second reference voltage generator may include: a first differential amplifier including a first input terminal for inputting the comparison voltage and an output terminal for outputting the amplification voltage; and a voltage difference including a plurality of resistors coupled in series between the amplification voltage and the ground a generator; the distribution voltage is selected by the voltage difference generator to output an amplification voltage corresponding to a voltage difference between the first power supply voltage and the first reference voltage from the first differential amplifier, and input the distribution voltage to the second input of the first differential amplifier And a voltage difference selecting unit of the terminal; and outputting a difference between the second power voltage and the amplified voltage as a reference voltage output unit of the second reference voltage.

The voltage difference selection unit may record an amplification voltage corresponding to a voltage difference between the first power supply voltage and the first reference voltage in the process of generating the gamma voltage, and the recorded amplification voltage may be output through the first differential amplifier after manufacturing the product.

The reference voltage output unit may include a second differential amplifier that outputs a difference between the power supply voltage supplied from the outside and the amplified voltage output from the first differential amplifier.

The gamma voltage generating device according to another embodiment includes a first reference voltage generator recorded in a voltage difference between a first power voltage for driving a plurality of pixels and a predetermined first reference voltage in a process of determining a gamma voltage in advance, And generating a second reference voltage as a difference between the second power voltage for driving the plurality of pixels and the recorded voltage difference; and a gamma voltage generator for generating a plurality of gamma voltages by using the second reference voltage.

The first reference voltage generator may include: a voltage difference generator including a plurality of resistors coupled in series between the comparison voltage and the ground voltage; and selecting and outputting the corresponding ones of the plurality of distribution voltages distributed to the plurality of resistors a voltage difference selection unit for a voltage difference between the power supply voltage and the first reference voltage; and a difference between the output second power supply voltage and the voltage output by the voltage difference selection unit as a reference voltage output of the second reference voltage unit.

The plurality of resistors included in the voltage difference generator may have a resistance determined by determining a cell distribution for a plurality of distribution voltages.

The voltage difference selecting unit may record a voltage difference between the first power source voltage and the first reference voltage in a process of determining the gamma voltage, and output a recorded voltage difference to the reference voltage output unit after manufacturing the product.

The reference voltage output unit may include a differential amplifier that outputs a difference between the second power supply voltage and a voltage output by the voltage difference selection unit.

The gamma voltage generator may include a reference voltage dividing unit including a plurality of resistors coupled in series between the second reference voltage and the reference voltage; by utilizing the distributed to the plurality of resistors a plurality of distribution voltages select a gamma voltage selection unit corresponding to a plurality of gamma voltages of a predetermined gray scale; and output a full gray by using the second reference voltage and the plurality of gamma voltage outputs selected by the gamma voltage selection unit A gamma voltage output unit of a plurality of gamma voltages.

The gamma voltage selection unit may include a first selector that selects a second gamma voltage that represents a gray level higher than a first gamma voltage corresponding to the second reference voltage.

The gamma voltage selection unit may further include a second selector that selects the seventh gamma voltage as the lowest voltage of the plurality of gamma voltages corresponding to the full gray scale.

The gamma voltage selection unit may further include a sixth selection of the sixth gamma voltage by using a distribution resistor connecting the second gamma voltage transmitted by the first selector and the seventh gamma voltage selected by the second selector. Selector.

The gamma voltage selection unit may further include a fifth of selecting the fifth gamma voltage by using a distribution resistor connecting the second gamma voltage transmitted by the first selector and the sixth gamma voltage selected by the sixth selector. Selector.

The gamma voltage selecting unit may further include: selecting the fourth gamma voltage by using a distributed resistor that connects the second gamma voltage transmitted by the first selector and the fifth gamma voltage selected by the fifth selector Selector.

The gamma voltage selecting unit may further include: selecting the third gamma voltage by using a distributed resistor that connects the second gamma voltage transmitted by the first selector and the fourth gamma voltage selected by the fourth selector Selector.

A second reference voltage generator that generates a reference voltage to generate a plurality of gamma voltages that drive a plurality of pixels in conjunction with a supply voltage is further included.

The second reference voltage generator can record the voltage difference between the first power voltage and the first reference voltage in the process of determining the gamma voltage, and can generate the second reference voltage as the second power voltage and the recorded voltage difference The difference.

The second reference voltage generator may include: a first differential amplifier including a first input terminal for inputting the comparison voltage and an output terminal for outputting the amplification voltage; and a voltage difference including a plurality of resistors coupled in series between the amplification voltage and the ground a generator; the distribution voltage is selected by the voltage difference generator to output an amplification voltage corresponding to a voltage difference between the first reference voltage of the first power supply voltage from the first differential amplifier, and input the distribution voltage to the second input end of the first differential amplifier And a voltage difference selection unit; and outputting a difference between the second power voltage and the amplification voltage as a reference voltage output unit of the second reference voltage.

The voltage difference selecting unit may record the amplified voltage corresponding to the voltage difference between the first power source voltage and the first reference voltage in the process of generating the gamma voltage, and the recorded amplified voltage may be output through the first differential amplifier after manufacturing the product.

The reference voltage output unit may include a second differential amplifier that outputs a difference between the power supply voltage supplied from the outside and the amplified voltage output from the first differential amplifier.

The gamma voltage generating method according to other embodiments includes recording a voltage difference between a first power supply voltage of a plurality of pixels driving a predetermined number of pixels in a process of determining a gamma voltage and a predetermined first reference voltage; The second reference voltage is used as a difference between the second power supply voltage for driving the plurality of pixels and the recorded voltage difference; and a plurality of gamma voltages are generated by using the second reference voltage.

The recorded voltage difference may include selecting a voltage corresponding to a voltage difference between the first power supply voltage and the first reference voltage from a plurality of distribution voltages distributed to a plurality of resistors coupled in series between the comparison voltage and the ground voltage.

The method may further include recording a first power voltage for driving the plurality of pixels and a second voltage of the predetermined first reference voltage in a process of predetermining the gamma voltage.

The method may further include generating a second reference voltage as a difference between the second power supply voltage driving the plurality of pixels and the recorded second voltage difference after the product is manufactured.

The generating of the plurality of gamma voltages can include generating a plurality of gamma voltages by using the second reference voltage and the second reference voltage.

The generating of the plurality of gamma voltages may include: selecting a plurality of gamma voltages corresponding to the predetermined gray scale by using a plurality of distribution voltages distributed to the plurality of resistors coupled in series between the second reference voltage and the reference voltage And generating a plurality of gamma voltages corresponding to the full gray level by using the second reference voltage and a plurality of gamma voltages corresponding to the predetermined gray scale.

The selection of the plurality of gamma voltages corresponding to the gray level in advance may include selecting a second gamma voltage indicating that the gray level is higher than the first gamma voltage corresponding to the second reference voltage.

The selection of the plurality of gamma voltages corresponding to the predetermined gray scale may include selecting the seventh gamma voltage as the lowest of the plurality of gamma voltages corresponding to the full gray scale.

The selection of the plurality of gamma voltages corresponding to the predetermined gray scale may include selecting the sixth gamma voltage by using a distributed resistor connecting the second gamma voltage and the seventh gamma voltage.

The selection of the plurality of gamma voltages corresponding to the predetermined gray scale may include selecting the fifth gamma voltage by using a distributed resistor connected between the second gamma voltage and the sixth gamma voltage.

The selection of the plurality of gamma voltages corresponding to the predetermined gray scale may include selecting the fourth gamma voltage by using a distributed resistor connected between the second gamma voltage and the fifth gamma voltage.

The selection of the plurality of gamma voltages corresponding to the predetermined gray scale may include selecting the third gamma voltage by using a distributed resistor connected between the second gamma voltage and the fourth gamma voltage.

The brightness in the process of determining the gamma voltage in advance and the brightness after the manufacture of the product are equally maintained, and the image quality characteristics of the display device can be improved.

10‧‧‧pixel circuit

100‧‧‧Signal Controller

200‧‧‧ scan driver

300‧‧‧Data Drive

400‧‧‧Gamma Voltage Generator

410‧‧‧Reference voltage division unit

420‧‧‧Gamma Voltage Selection Unit

421‧‧‧First selector

422‧‧‧Second selector

423‧‧‧ third selector

424‧‧‧fourth selector

425‧‧‧ fifth selector

426‧‧‧ sixth selector

430‧‧‧Gamma voltage output unit

433~436‧‧‧Distributed resistor

440‧‧‧Microcontroller

500‧‧‧reference voltage generator

500-1‧‧‧First reference voltage generator

500-2‧‧‧Second reference voltage generator

510‧‧‧Voltage difference generator

520‧‧‧Voltage difference selection unit

530‧‧‧reference voltage output unit

531‧‧‧Differential Amplifier

540‧‧‧First Differential Amplifier

550‧‧‧Voltage difference generator

560‧‧‧Voltage difference selection unit

570‧‧‧reference voltage output unit

571‧‧‧Second differential amplifier

600‧‧‧ display unit

M1‧‧‧Switching transistor

M2‧‧‧ drive transistor

RC1~RC6‧‧‧ record value

V0~V255‧‧‧ gamma voltage

VREG, VREG', VREG" ‧ ‧ reference voltage

VGS, VGS', VGS" ‧ ‧ reference voltage

VREF‧‧‧Comparative voltage

Va‧‧‧First voltage

Vb‧‧‧second voltage

Vo‧‧‧ difference

ΔV, △Vg, △V1, △V2‧‧‧ voltage difference

R1~R4, R11~R14‧‧‧ resistors

P‧‧‧ position

Cst‧‧‧Support capacitor

D1~Dm‧‧‧ data line

S1~Sn‧‧‧ scan line

PX‧‧ ‧ pixels

ELVDD, ELVSS, ELVDD', ELVSS', ELVDD", ELVSS" ‧‧‧Power supply voltage

CONT2‧‧‧ data control signal

DAT‧‧‧ image data signal

CONT1‧‧‧ scan control signal

R, G, B‧‧‧ video signals

Hsync‧‧‧ horizontal sync signal

Vsync‧‧‧ vertical sync signal

MCLK‧‧‧ master clock signal

Fig. 1 is a block diagram of a display device according to an embodiment.

Figure 2 is a circuit diagram of a pixel in accordance with an embodiment.

Figure 3 is a block diagram of a gamma voltage generator in accordance with an embodiment.

Figure 4 is a block diagram of a first reference voltage generator in accordance with an embodiment.

Fig. 5 is a view showing the relationship between the ELVDD voltage and the reference voltage in the process of predetermining the gamma voltage and after the manufacture of the product according to the embodiment.

Fig. 6 is a view showing the relationship between the ELVDD voltage and the reference voltage of the gamma voltage in the process of predetermining the gamma voltage in the process of conventionally determining the gamma voltage.

Figure 7 is a block diagram of a second reference voltage generator in accordance with an embodiment.

Fig. 8 is a view showing the relationship between the ELVDD voltage and the reference voltage in the process of predetermining the gamma voltage and after manufacturing the product according to the embodiment.

Fig. 9 is a view showing the relationship between the ELVDD voltage and the reference voltage of the gamma voltage in the conventional process of predetermining the gamma voltage and after the manufacture of the product.

EXAMPLES The accompanying drawings, which are incorporated herein by reference in the claims It is to be understood by those of ordinary skill in the art that the invention may be modified or modified without departing from the spirit and scope of the invention.

In addition, in the several exemplary embodiments, elements having the same structure are denoted by the same symbols, and are typically described in relation to the first exemplary embodiment. In the remaining embodiments, only elements different from those of the first exemplary embodiment are described.

In order to clearly describe the embodiments, the parts that are not related to the description are omitted, and the same symbols are used in all the drawings to denote the same or similar parts.

Throughout the specification and the accompanying claims, when the elements are "coupled" to other elements, the elements can be "directly coupled" or "electrically coupled" to the other elements. In addition, the term "comprise" and variations thereof "comprises" or "comprising" are to be understood to include the elements but not to exclude other elements.

Fig. 1 is a block diagram of a display device according to an embodiment. Referring to FIG. 1, the display device includes a signal controller 100, a scan driver 200, a data driver 300, a gamma voltage generator 400, a reference voltage generator 500, and a display unit 600.

The signal controller 100 receives the image signals R, G, and B input by the external device, and inputs control signals for controlling the display thereof. The image signals R, G, and B contain brightness information of each pixel PX, and the brightness has a gray level containing a predetermined number, such as 1024=2 ¹⁰ , 256=2 ⁸ or 64=2 ⁶ . For example, the input control signal may include a vertical sync signal Vsync, a horizontal sync signal Hsync, a master clock signal MCLK, and a data enable signal DE.

The signal controller 100 appropriately processes the input image signals R, G, and B based on the input image signals R, G, and B and the input control signals for the operating conditions of the display unit 600 and the data driver 300, and generates the scan control signals CONT1 and data. Control signal CONT2 and image data signal DAT. The signal controller 100 transmits the scan control signal CONT1 to the scan driver 200. The scan controller 100 transmits the data control signal CONT2 and the image data signal DAT to the data driver 300.

The display unit 600 includes a plurality of scan lines S1-Sn, a plurality of data lines D1-Dm, and a plurality of pixels PX. The plurality of pixels PX are connected to the plurality of scanning lines S1-Sn and the data lines D1-Dm and arranged in an approximate matrix. The plurality of scanning lines S1-Sn extend in the approximate column direction and are almost parallel to each other. The plurality of data lines D1-Dm extend in the approximate row direction and are almost parallel to each other. The plurality of pixels PX of the display unit 600 are supplied with an ELVDD voltage and an ELVSS voltage from the outside.

The scan driver 200 is connected to the plurality of scan lines S1-Sn, and applies a turn-on voltage Von including a data signal application combined with the turn-on pixel PX, and a turn-off voltage Voff disconnected from the plurality of scan lines S1-Sn according to the scan control signal CONT1. Scan the signal.

The scan control signal CONT1 includes a scan start signal SSP and a clock signal CLK. The scan start signal SSP is a signal for generating a first scan signal to display an image of a frame. The clock signal CLK is a synchronous signal for continuously applying the scan signal to the plurality of scan lines S1-Sn.

The data driver 300 connects a plurality of data lines D1-Dm and selects a gray scale voltage according to the image data signal DAT. The data driver 300 selects a gray scale voltage from a plurality of gamma voltages supplied from the gamma voltage generator 400 in accordance with the image data signal DAT. The data driver 300 applies the selected gray scale voltage as a data signal to the plurality of data lines D1-Dm according to the data control signal CONT2.

The gamma voltage generator 400 generates a plurality of gamma voltages of a plurality of gray scales and supplies them to the data driver 300. A plurality of gamma voltages of a plurality of gray levels are used as gray scale voltages. The gamma voltage generator 400 receives the reference voltage VREG and the reference voltage VGS from the reference voltage generator 500, and divides between the reference voltage VREG and the reference voltage VGS to generate a plurality of gamma voltages. The reference voltage VREG as a voltage for generating a plurality of gamma voltages may be a voltage having the highest voltage value among the plurality of gamma voltages.

The reference voltage generator 500 generates and supplies a reference voltage VREG to the gamma voltage generator 400. The reference voltage generator 500 compares the reference voltage VREG with the externally supplied power supply voltage such that the voltage difference between the power supply voltage and the reference voltage VREG is the same in the process of predetermining the gamma voltage and after manufacturing the product. The power supply voltage includes a first power supply voltage ELVDD' to drive a plurality of pixels PX during the predetermined gamma voltage, and a second power supply voltage ELVDD" to drive the plurality of pixels PX after the product is manufactured.

Therefore, the reference voltage generator 500 records the voltage difference ΔV between the first power supply voltage ELVDD' and the reference voltage VREG' supplied in the process of determining the gamma voltage in advance. In addition, reference electricity The voltage generator 500 generates a reference voltage VREG' which is a difference between the second power source voltage ELVDD" and the voltage difference ΔV supplied after the product is manufactured.

The first power supply voltage ELVDD' supplied in the process of predetermining the gamma voltage and the second power supply voltage ELVDD" supplied after the manufacturing of the product may vary depending on the output deviation of the DC/DC converter for the connector resistance deviation. The voltage difference ΔV between the power supply voltage and the reference voltage can be determined equally in the process of determining the gamma voltage in advance and after manufacturing the product.

Further, the reference voltage generator 500 generates a reference voltage VGS and supplies it to the gamma voltage generator 400. The reference voltage generator 500 and the reference voltage VGS operate together with the externally supplied power supply voltage such that the voltage difference between the power supply voltage and the reference voltage VGS is the same in the process of determining the gamma voltage and after manufacturing the product.

Therefore, the reference voltage generator 500 records the voltage difference ΔV' between the first power source voltage ELVDD' and the reference voltage VGS' supplied in the process of determining the gamma voltage in advance. Further, the reference voltage generator 500 generates a difference between the reference voltage VGS" as the second power source voltage ELVDD after being supplied to the product and the voltage difference ΔV'.

Therefore, the voltage difference ΔV between the power supply voltage and the reference voltage in the process of determining the gamma voltage in advance and after the product is manufactured can be maintained equally.

The reference voltage generator 500 includes a first reference voltage generator that generates a reference voltage VREG to be supplied to the gamma voltage generator 400, and a second reference voltage generator that generates a reference voltage VGS to be supplied to the gamma voltage generator 400. The composition of the first reference voltage generator and the second reference voltage generator is described in the following FIGS. 4 and 7.

The gamma voltage generating device may include a gamma voltage generator 400 and a reference voltage generator 500.

Each of the driving devices 100, 200, 300, 400, and 500 may be directly mounted outside the pixel region in the form of at least one integrated circuit chip, and mounted on the flexible printed circuit film in the form of a tape carrier package (TCP). The display unit 600 is mounted on a separate printed circuit board (PCB). Alternatively, it may be integrated in the display unit 600 together with the scan lines S1-Sn and the data lines D1-Dm.

Figure 2 is a circuit diagram of a pixel in accordance with an embodiment.

Referring to FIG. 2, the pixel PX of the organic light emitting diode (OLED) display includes an organic light emitting diode OLED and a pixel circuit 10 to control the organic light emitting diode OLED. The pixel circuit 10 includes a switching transistor M1, a driving transistor M2, and a sustaining capacitor Cst.

Here, the pixel circuit 10 includes two transistors and one capacitor, however, the pixel circuit of the organic light emitting diode (OLED) display can operate for different compositions, and the display device does not limit the composition of the pixel circuit according to the embodiment.

The switching transistor M1 includes a scan gate Si gate electrode, one end of which is connected to the data line Dj, and the other end of which is connected to the gate electrode of the driving transistor M2.

The driving transistor M2 includes a gate electrode connected to the other end of the switching transistor M1, one end is connected to the ELVDD voltage, and the other end is connected to the anode of the organic light emitting diode (OLED).

The sustain capacitor Cst includes one end connected to the gate electrode of the driving transistor M2, and the other end connected to one end of the driving transistor M2. The sustain capacitor Cst charges the data voltage applied to the gate electrode of the driving transistor M2, and maintains the data voltage after the switching transistor M1 is turned off.

The organic light emitting diode (OLED) includes an anode connected to the other end of the driving transistor M2, and a cathode connected to the ELVSS voltage.

The switching transistor M1 and the driving transistor M2 may be p-channel field effect transistors. Here, the turn-on voltage of the switching transistor M1 and the driving transistor M2 is turned to a logic low level voltage, and the off voltage of the switching transistor is turned off to a logic high level voltage.

The switching transistor M1 and the driving transistor M2 are p-channel field effect transistors, however, at least one of the switching transistor M1 and the driving transistor M2 may be an n-channel field effect transistor, and the n-channel field effect transistor is turned on. The turn-on voltage is a logic high voltage, and the turn-off voltage that is turned off is a logic low voltage.

If the on-voltage Von is applied to the scan line Si, the switching transistor M1 is turned on and the data signal applied to the data line Dj is applied to one end of the sustain capacitor Cst via the turned-on switching transistor M1 to charge the sustain capacitor Cst. The driving transistor M2 controls the amount of current flowing from the ELVDD power source voltage to the organic light emitting diode (OLED) by a voltage value corresponding to the charging of the sustaining capacitor Cst. In other words, the driving transistor M2 controls the amount of current flowing to the organic light emitting diode (OLED) in accordance with the difference between the ELVDD voltage and the gate voltage applied to the gate electrode.

The organic light emitting diode (OLED) emits light corresponding to the amount of current flowing through the driving transistor M2. An organic light emitting diode (OLED) emits a primary color of one color. Examples of primary color light may be, for example, three primary colors of red, green, and blue, and the desired color is displayed by a combination of three primary color spaces or time. In this example, a portion of the organic light emitting diode (OLED) can emit white light, and if so, the brightness increases. Different from this, all the pixels of the PX organic light emitting diode (OLED) can emit white light, and a part of the pixel PX can further include a color filter that converts white light emitted by the organic light emitting diode (OLED) to any one of the primary colors. Light film (not shown).

Figure 3 is a block diagram of a gamma voltage generator in accordance with an embodiment. Referring to FIG. 3, the gamma voltage generator 400 includes a reference voltage dividing unit 410, a gamma voltage selecting unit 420, a gamma voltage output unit 430, and a microcontroller 440.

The reference voltage dividing unit 410 includes a plurality of resistors coupled in series between the reference voltage VREG and the reference voltage VGS. The reference voltage dividing unit 410 outputs a plurality of distribution voltages divided into a plurality of resistors to the gamma voltage selection unit 420 based on the reference voltage VREG and the reference voltage VGS.

At this time, the reference voltage VREG is transmitted to the gamma voltage output unit 430, and the reference voltage VREG becomes the first gamma voltage V0 as the highest voltage among the plurality of gamma voltages. When the driving transistor M2 of the pixel is a p-channel field effect transistor, the first gamma voltage V0 is a voltage at which the organic light emitting diode (OLED) emits at the lowest gray level. When the driving transistor M2 of the pixel is an n-channel field effect transistor, the first gamma voltage V0 is a voltage at which the organic light emitting diode (OLED) emits at the highest gray level.

The microcontroller 440 supplies the recording values RC1 to RC6 to control the gamma voltage to the gamma voltage selection unit 420 in minutes.

The gamma voltage selection unit 420 includes a plurality of selectors 421 to 426 that select a gamma voltage corresponding to a predetermined gray scale by using a plurality of distribution voltages.

The first selector 421 selects the second gamma voltage V1 among the plurality of distribution voltages corresponding to the first record value RC1 supplied from the microcontroller 440. The second gamma voltage V1 is a voltage representing a second low gray scale and lower than the first gamma voltage V0. The first selector 421 transmits the second gamma voltage V1 to the gamma voltage output unit 430, the third selector 423, the fourth selector 424, the fifth selector 425, and the sixth selector 426.

The second selector 422 selects the seventh gamma voltage V255 from the plurality of distribution voltages and transmits it to the gamma voltage output unit 430 in accordance with the second recording value RC2 supplied from the microcontroller 440. The seventh gamma voltage V255, which is the gamma voltage having the lowest voltage among the plurality of gamma voltages, may be a voltage representing the highest gray scale in the full gray scale.

For example, when the driving transistor M2 of the pixel is a p-channel field effect transistor, the seventh gamma voltage V255 may be a voltage of the organic light emitting diode (OLED) emitting light at the highest gray level.

Meanwhile, when the driving transistor M2 of the pixel is an n-channel field effect transistor, the seventh gamma voltage V255 may be a voltage at which the organic light emitting diode emits light at the lowest gray level.

The third selector 423 selects the third gamma voltage V19 in accordance with the third record value RC3 supplied from the microcontroller 440 and transfers it to the gamma voltage output unit 430. The third selector 423 can select the third gamma voltage by connecting the second gamma voltage V1 transmitted by the first selector 421 and the fourth gamma voltage V43 selected by the fourth selector 424 by using the distributed resistor 433. V19.

The fourth selector 424 selects the fourth gamma voltage V43 in accordance with the fourth record value RC4 supplied from the microcontroller 440 and transfers it to the gamma voltage output unit 430. The fourth selector 424 can select the fourth by using the distributed resistor 434 between the second gamma voltage V1 transmitted by the first selector 421 and the fifth gamma voltage V87 selected by the fifth selector 425. Gamma voltage V43.

The fifth selector 425 selects the fifth gamma voltage V87 in accordance with the fifth record value RC5 supplied from the microcontroller 440 and transmits it to the gamma voltage output unit 430. The fifth selector 425 can select the fifth by using the distributed resistor 435 between the second gamma voltage V1 transmitted by the first connector 421 and the sixth gamma voltage V71 selected by the sixth selector 426. Gamma voltage V87.

The sixth selector 426 selects the sixth gamma voltage in accordance with the sixth recording value RC6 supplied from the microcontroller 440 and transmits it to the gamma voltage output unit 430. The sixth selector 426 can select the sixth gamma by using a distributed resistor 436 connecting the second gamma voltage V1 transmitted by the first selector and the seventh gamma voltage V255 selected by the second selector. Voltage V171.

The gamma voltage output unit 430 outputs the full gray scale by using the reference voltage VREG supplied from the reference voltage generator 500 and the gamma voltages V1, V19, V43, V87, V171, and V255 selected by the plurality of selectors 421 to 426. The plurality of gamma voltages V0 to V255.

Figure 4 is a block diagram of a first reference voltage generator in accordance with an embodiment.

Referring to FIG. 4, the first reference voltage generator 500-1 may include a voltage difference generator 510, a voltage difference selecting unit 520, and a reference voltage output unit 530.

The voltage difference generator 510 includes a plurality of resistors coupled in series between the comparison voltage VREF and the ground, and a voltage difference between the comparison voltage VREF and the ground voltage is divided into a plurality of resistors to generate a plurality of distribution voltages. At this time, among the plurality of distribution voltages generated by the voltage difference generator 510, the distribution voltage corresponding to the voltage difference between the ELVDD voltage and the first gamma voltage V0 is selected by the voltage difference selection unit 520.

For example, when the driving transistor M2 of the pixel is a p-channel field effect transistor, the voltage difference between the first gamma voltage V0 and the ELVDD voltage of the organic light emitting diode (OLED) at the lowest gray level illumination may be approximately 0.2V to 0.6V.

At this time, the voltage difference generator 510 generates a plurality of distribution voltages including the range from 0.2V to 0.6V. Further, the plurality of resistors included in the voltage difference generator 510 generate a plurality of distribution voltages as predetermined units such that the voltage difference between the first gamma voltages V0 and ELVDD voltages can be controlled minutely. Therefore, the number of resistors forming the voltage difference generator 510 and the resistance of each resistor are controlled. For example, a plurality of resistors can be constructed for a plurality of distribution voltage distributions as 6.25 mV cells.

The voltage difference selection unit 520 selects a voltage from a plurality of distribution voltages corresponding to the voltage difference ΔV between the first power supply voltage ELVDD' and the reference voltage VREG' in the process of determining the gamma voltage in advance. The voltage difference selecting unit 520 records the voltage difference ΔV between the first power source voltage ELVDD' and the reference voltage VREG' in the process of determining the gamma voltage in advance, and outputs a recorded voltage difference ΔV after the product is manufactured.

The reference voltage output unit 530 outputs a difference of the voltage difference ΔV along the second power source voltage ELVDD" as the reference voltage VREG". The reference voltage output unit 530 includes a differential amplifier 531.

The first input terminal (+) of the differential amplifier 531 is input with a first voltage Va formed between the second resistor R2 and the fourth resistor R4 by the second power voltage ELVDD", and the second input terminal (-) A second voltage Vb formed between the first resistor R1 and the third resistor R3 by the voltage difference ΔV is input. The differential amplifier 532 outputs a difference Vo between the first voltage Va and the second voltage Vb.

At this time, the resistances of all the resistors R1 to R4 are the same. If the resistances of all the resistors R1 to R4 are the same, the reference voltage VREG" outputted by the differential amplifier 531 becomes VREG" = ELVDD" - ΔV.

Although the first power supply voltage ELVDD' supplied in the process of predetermining the gamma voltage is different from the second power supply voltage ELVDD" supplied after manufacturing the product, the first reference voltage generator 500-1 may predetermine the gamma voltage During the process and after the manufacture of the product, a reference voltage that equally determines the voltage difference ΔV between the power supply voltage and the reference voltage is output. This will be described with reference to FIG.

Fig. 5 is a view showing the relationship between the ELVDD voltage and the reference voltage in the process of predetermining the gamma voltage according to the embodiment and after manufacturing the product.

Referring to Fig. 5, in the process of determining the gamma voltage in advance, ELVDD' is supplied to the display panel via the DC/DC converter of the test apparatus. The reference voltage is determined as VREG' by a process of determining the gamma voltage in advance, and the voltage difference between the ELVDD' voltage and the reference voltage VREG' becomes ΔV1. The voltage difference ΔV1 between the ELVDD' voltage and the reference voltage VREG' is recorded in the first reference voltage generator 500-1.

After manufacturing the display device, the ELVDD" voltage is supplied to the display panel via the DC/DC converter of the display device. The output deviation between the DC/DC converter of the display device and the DC/DC converter of the test device, and the connector The resistance, the ELVDD" voltage supplied after the product is manufactured, the resistance deviation is generated along the ELVDD' voltage supplied during the predetermined gamma voltage (ELVDD" ≠ ELVDD').

The first reference voltage generator 500-1 receives the ELVDD" voltage after manufacturing the display device. The voltage difference selecting unit 520 outputs a voltage difference ΔV1 recorded in the process of determining the gamma voltage in advance. The reference voltage output unit 530 outputs the difference between the ELVDD" voltage and the voltage difference ΔV1 as the reference voltage VREG".

Therefore, the voltage difference ΔV2 between the ELVDD" voltage and the reference voltage VREG" after the manufacturing of the display device becomes a voltage difference between the ELVDD' voltage and the reference voltage VREG' in the process of determining the gamma voltage in advance. ΔV1 is the same (ΔV1 = ΔV2).

If the reference voltage supplied to the gamma voltage generator 400 is inconsistent with ELVDD" and is supplied as a predetermined voltage in the process of determining the gamma voltage in advance, the voltage difference between the ELVDD" voltage and the reference voltage after the product is manufactured It can be different from the process of predetermining the gamma voltage. In this example, the brightness cannot be maintained in the same process as the predetermined gamma voltage after the product is manufactured and the image quality characteristics of the display device may deteriorate. This will be described with reference to Figure 6.

Fig. 6 is a view showing the relationship between the ELVDD voltage and the reference voltage of the gamma voltage in the process of predetermining the gamma voltage in the process of conventionally determining the gamma voltage.

Referring to Fig. 6, the ELVDD' voltage is supplied to the display panel via the DC/DC converter of the test apparatus during the predetermined gamma voltage. The reference voltage is determined as VREG' by a process of determining the gamma voltage in advance, and the voltage difference between the ELVDD' voltage and the reference voltage VREG' becomes ΔV1.

After manufacturing the display device, the ELVDD' voltage is supplied to the display panel (ELVDD"≠ELVDD') via a DC/DC converter provided in the display device. When the reference voltage VREG' in the process of predetermining the gamma voltage is also used After the display device is manufactured, the voltage difference ΔV2 between the ELVDD" voltage and the reference voltage VREG' after the manufacturing of the display device is different between the ELVDD' voltage and the reference voltage VREG' in the process of determining the gamma voltage in advance. The voltage difference is ΔV1 (ΔV1 ≠ ΔV2). Therefore, the brightness after manufacturing the product can be different from the brightness in the process of determining the gamma voltage in advance, so that the image quality characteristics of the display device may deteriorate.

Figure 7 is a block diagram of a second reference voltage generator in accordance with an embodiment.

Referring to FIG. 7, the second reference voltage generator 500-2 includes a first differential amplifier 540, a voltage difference generator 550, a voltage difference selecting unit 560, and a reference voltage output unit 570.

The comparison voltage VREF is input to the first input terminal (+) of the first differential amplifier 540, and the distribution voltage selected from the voltage difference selection unit 560 is input to the second input terminal (-). The first differential amplifier 540 outputs an amplified voltage ΔVg corresponding to a voltage difference between the reference voltage VGS and the ELVDD voltage to the output terminal according to the voltages input to the first input terminal (+) and the second input terminal (−). The reference voltage VGS is used to generate a voltage of a plurality of gamma voltages in the gamma voltage generator 400.

The voltage difference generator 550 includes a plurality of resistors coupled in series between the amplified voltage ΔVg of the first differential amplifier 540 and the ground and divides the voltage difference between the amplified voltage ΔVg of the first differential amplifier 540 and the ground to a plurality of A resistor to generate a plurality of distribution voltages.

The voltage difference selection unit 560 selects the distribution voltage to output an amplification voltage ΔVg corresponding to the voltage difference between the reference voltage VGS and the ELVDD voltage via the first differential amplifier 540. When the position selected by the voltage difference generator 550 corresponding to the distribution voltage is referred to as P, the total resistance of the resistance between the position P and the ground is referred to as Ra, and the position P and the output resistance of the first differential amplifier 540 are The total resistance is referred to as Rb. At this time, the amplification voltage ΔVg=VREF*(1+Rb/Ra) is output from the first differential amplifier 540.

For example, the voltage difference between the reference voltage VGS and the ELVDD voltage for generating a plurality of gamma voltages of the plurality of gray levels by the gamma voltage generator 400 may range from about 3.6V to 4.6V. When the comparison voltage VREF is 2V, the plurality of resistors included in the voltage difference generator 550 may be configured to have a range of Rb/Ra of 0.8 to 1.3. Further, the plurality of resistors included in the voltage difference generator 550 may be configured to control the amplification voltage ΔVg in minutes and output in units of 100 mV.

The voltage difference selection unit 560 selects the distribution voltage so that the voltage difference corresponding to the first power supply voltage ELVDD' and the amplification voltage ΔVg corresponding to the reference voltage VGS' in the process of determining the gamma voltage in advance are output from the first differential amplifier 540. In addition, the voltage difference selection unit 560 records the predetermined gamma In the process of the voltage, the amplified voltage ΔVg corresponding to the voltage difference between the first power supply voltage ELVDD' and the reference voltage is outputted, and the recorded amplified voltage ΔVg is output via the first differential amplifier 540.

The reference voltage output unit 570 outputs a difference between the second power source voltage ELVDD" and the amplified voltage ΔVg as the reference voltage VGS". The reference voltage output unit 570 includes a second differential amplifier 571.

The first input terminal (+) of the second differential amplifier 571 is formed by the second power supply voltage ELVDD" at a first voltage Va between the second resistor R12 and the fourth resistor R14, and the second input terminal (- The second voltage Vb formed between the first resistor R11 and the third resistor R13 is input by the amplification voltage ΔVg. The second differential amplifier 571 outputs a difference Vo between the first voltage Va and the second voltage Vb.

At this time, the resistances of all the resistors R11 to R14 may be the same. If the resistances of all the resistors R11 to R14 are the same, the reference voltage VGS" outputted by the second differential amplifier 571 becomes VGS" = ELVDD" - ΔVg.

Although the first power supply voltage ELVDD' is supplied in the process of determining the gamma voltage in advance and the second power supply voltage ELVDD" is supplied to the manufactured product, the second reference voltage generator 500-2 outputs the reference voltage so that the gamma voltage is predetermined The voltage difference ΔV' between the power supply voltage and the reference voltage during and after the manufacture of the product is the same. This will be described with reference to FIG.

Fig. 8 is a view showing the relationship between the ELVDD voltage and the reference voltage in the process of predetermining the gamma voltage and after manufacturing the product according to the embodiment.

Referring to Fig. 8, in the process of determining the gamma voltage in advance, the ELVDD' voltage is supplied to the display panel via the DC/DC converter of the test apparatus. The voltage difference between the ELVDD' voltage and the reference voltage VGS' is determined to be ΔV1' by the process reference voltage which determines the gamma voltage in advance. The voltage difference ΔV1' between the ELVDD' voltage and the reference voltage VGS' is recorded to the second reference voltage generator 500-2.

After manufacturing the display device, the ELVDD" voltage is supplied to the display panel via the DC/DC converter of the display device. For the ELVDD" voltage supplied after the product is manufactured, the DC/DC converter and the test device are DC/DC according to the display device. The output deviation between the converters, as well as the resistance of the connector, which is generated along the ELVDD' voltage (ELVDD" ≠ ELVDD') supplied during the predetermined gamma voltage.

The second reference voltage generator 500-2 receives the ELVDD" voltage after manufacturing the display device. The voltage difference selection unit 560 outputs the amplified voltage ΔVg recorded in the process of determining the gamma voltage via the first differential amplifier 540. The reference voltage output The unit 570 outputs a difference between the ELVDD" voltage and the amplified voltage ΔVg as the reference voltage VGS".

Therefore, the voltage difference ΔV2' between the ELVDD" voltage and the reference voltage VGS" after the manufacturing of the display device becomes a voltage difference between the ELVDD' voltage and the reference voltage VGS' in the process of determining the gamma voltage in advance. ΔV1' is the same (ΔV1' = ΔV2').

If the reference voltage supplied to the gamma voltage generator 400 is inconsistent with ELVDD" and is supplied as a predetermined voltage in the process of determining the gamma voltage in advance, the voltage difference between the ELVDD" voltage and the reference voltage after the product is manufactured It can be different from the process of predetermining the gamma voltage. In this example, the brightness cannot be maintained in the same process as the predetermined gamma voltage after the product is manufactured, and the image quality characteristics of the display device may deteriorate. This will be described with reference to Figure 9.

Fig. 9 is a view showing the relationship between the ELVDD voltage and the reference voltage of the gamma voltage in the conventional process of predetermining the gamma voltage and after the manufacture of the product.

Referring to Fig. 9, the ELVDD' voltage is supplied to the display panel in the process of predetermining the gamma voltage via the DC/DC converter of the test apparatus. The reference voltage is determined as VGS' by the process of determining the gamma voltage in advance, and the voltage difference between the ELVDD' voltage and the reference voltage VGS' becomes ΔV1'.

The ELVDD' voltage is supplied to the display panel (ELVDD" ≠ ELVDD') after being manufactured by the DC/DC converter provided in the display device. It is also used to predetermine the gamma power. The voltage difference ΔV2' between the ELVDD" voltage after the manufacturing of the display device and the reference voltage VGS' after the manufacturing of the display device is determined by the predetermined reference voltage VGS' during the pressing process is different from the predetermined gamma voltage. The voltage difference between the ELVDD' voltage and the reference voltage VGS' is ΔV1' (ΔV1' ≠ ΔV2'). Therefore, the brightness after manufacturing the product can be different from the predetermined gamma voltage. The brightness makes the image quality characteristics of the display device worse.

However, according to the above description, the voltage difference between the ELVDD voltage and the reference voltage in the process of determining the gamma voltage, and the voltage difference between the ELVDD voltage and the reference voltage and the reference voltage and reference voltage after manufacturing the product to the ELVDD voltage are determined. Consistently, the deterioration of the image quality characteristics of the display device can be solved.

The above description and the detailed description are for the purpose of illustration and description, and are not intended to may. In summary, the true technical scope of the embodiments should be based on the technical spirit of the scope of the patent application.

100‧‧‧Signal Controller

200‧‧‧ scan driver

300‧‧‧Data Drive

400‧‧‧Gamma Voltage Generator

500‧‧‧reference voltage generator

600‧‧‧ display unit

D1~Dm‧‧‧ data line

S1~Sn‧‧‧ scan line

PX‧‧ ‧ pixels

ELVDD, ELVSS‧‧‧ voltage

CONT2‧‧‧ data control signal

DAT‧‧‧ image data signal

CONT1‧‧‧ scan control signal

R, G, B‧‧‧ video signals

Hsync‧‧‧ horizontal sync signal

Vsync‧‧‧ vertical sync signal

MCLK‧‧‧ master clock signal

Claims (47)

A display device comprising: a display unit comprising a plurality of pixels connecting a plurality of data lines; and a data driver for selecting a gray scale voltage from a plurality of gamma voltages according to an image data signal to apply the gray scale voltage to the a plurality of data lines; a gamma voltage generator for generating the plurality of gamma voltages; and a first reference voltage generator for generating a reference voltage to generate a plurality of gamma that cooperates with a power supply voltage to drive the plurality of pixels a voltage voltage, wherein a voltage difference between one of the first power voltage and a first reference voltage in the process of determining the gamma voltage is recorded in the first reference voltage generator, and the first reference voltage is generated The device generates a second reference voltage as a difference between a second supply voltage and the recorded voltage difference. The display device of claim 1, wherein the first reference voltage generator comprises: a voltage difference generator comprising a plurality of resistors coupled in series between a comparison voltage and a ground voltage; The voltage difference selecting unit selects and outputs one of voltage voltages corresponding to one of the first power voltage and the first reference voltage among the plurality of power distribution voltages distributed to the plurality of resistors; and a reference voltage output unit And outputting, as the second reference voltage, a difference between the second power voltage and the voltage output by the voltage difference selecting unit. The display device of claim 2, wherein the plurality of resistors included in the voltage difference generator have a resistance determined by a predetermined unit distribution for the plurality of distribution voltages. The display device of claim 2, wherein the voltage difference selecting unit records the voltage difference between the first power voltage and the first reference voltage in a process of determining the gamma voltage in advance, and After the product is manufactured, the recorded voltage difference is output to the reference voltage output unit. The display device of claim 2, wherein the reference voltage output unit comprises a differential amplifier that outputs a difference between the power supply voltage supplied from the outside and the voltage outputted by the voltage difference selection unit. The display device of claim 1, wherein the gamma voltage generator comprises: a reference voltage dividing unit, comprising: a plurality of resistors coupled in series between the reference voltage and a reference voltage; a gamma The voltage selection unit selects the plurality of gamma voltages corresponding to the predetermined gray scale by using a plurality of distribution voltages distributed to the plurality of resistors; and a gamma voltage output unit by using the reference voltage The reference voltage provided by the device and the plurality of gamma voltages selected from the gamma voltage selection unit output a plurality of gamma voltages corresponding to full gray scale. The display device of claim 6, wherein the gamma voltage selection unit comprises: selecting one of the second gamma voltages that is one of the first gamma voltages that is higher than a corresponding one of the corresponding reference voltages. Selector. The display device of claim 7, wherein the gamma voltage selecting unit further comprises selecting a seventh gamma voltage as one of a lowest voltage of the plurality of gamma voltages corresponding to the full gray level. Selector. The display device of claim 8, wherein the gamma voltage selection unit further comprises the second gamma voltage transmitted by the first selector by using a connection and the second selector selected by the second selector One of the seventh gamma voltage distribution resistors selects a sixth selector of a sixth gamma voltage. The display device of claim 9, wherein the gamma voltage selection unit further comprises the second gamma voltage transmitted by the first selector by using a connection and the selected by the sixth selector One of the sixth gamma voltage distribution resistors selects a fifth selector of a fifth gamma voltage. The display device of claim 10, wherein the gamma voltage selection unit further comprises the second gamma voltage transmitted by the first selector by using a connection and the selected by the fifth selector One of the fifth gamma voltage distribution resistors selects a fourth selector of a fourth gamma voltage. The display device of claim 11, wherein the gamma voltage selection unit further comprises the second gamma voltage transmitted by the first selector by using a connection and the selected by the fourth selector One of the fourth gamma voltage distribution resistors selects a third selector of a third gamma voltage. The display device of claim 8, wherein the gamma voltage generator further comprises a microcontroller to provide a recording value to control the gamma voltage to the gamma voltage selection unit in minutes. The display device of claim 1, further comprising a second reference voltage generator that generates a reference voltage to generate the plurality of gamma voltages that drive the plurality of pixels in cooperation with the power supply voltage. The display device of claim 14, wherein a voltage difference between one of the first power supply voltage and a first reference voltage in the process of predetermining the gamma voltage is recorded at the second reference voltage And generating, by the second reference voltage generator, a second reference voltage as a difference between a second power voltage and the recorded voltage difference. The display device of claim 15, wherein the second reference voltage generator comprises: a first differential amplifier includes a first input terminal for inputting a comparison voltage and an output terminal for outputting an amplification voltage; a voltage difference generator comprising a plurality of resistors coupled in series between the amplification voltage and a ground a voltage difference selecting unit, wherein the voltage difference generator selects a power distribution voltage to output the amplified voltage corresponding to the voltage difference between the first power voltage and the first reference voltage from the first differential amplifier, and And inputting the distribution voltage to the second input end of the first differential amplifier; and a reference voltage output unit, outputting a difference between the second power supply voltage and the amplified voltage as the second reference voltage. The display device of claim 16, wherein the voltage difference selection unit records the amplified voltage corresponding to the voltage difference between the first power supply voltage and the first reference voltage during the generation of the gamma voltage And the amplified voltage of the record is output via the first differential amplifier after the product is manufactured. The display device of claim 16, wherein the reference voltage output unit comprises a second differential amplifier that outputs a difference between the power supply voltage supplied from the outside and the amplified voltage outputted by the first differential amplifier. A gamma voltage generating device includes: a first reference voltage generator that records one of driving a plurality of pixels in a process of predetermining a gamma voltage, and one of a predetermined one of the first reference voltages a voltage difference, and generating a second reference voltage as a difference between a second power voltage for driving the plurality of pixels and a voltage difference of the recording; and a gamma voltage generator by using the second reference voltage A plurality of gamma voltages are generated. The gamma voltage generating device of claim 19, wherein the first reference voltage generator comprises: a voltage difference generator comprising: a plurality of resistors coupled in series between a comparison voltage and a ground voltage; a voltage difference selection unit for selecting and outputting a plurality of distribution voltages distributed to the plurality of resistors a voltage corresponding to the voltage difference between the first power voltage and the first reference voltage; and a reference voltage output unit that outputs a difference between the second power voltage and the voltage output by the voltage difference selecting unit As the second reference voltage. The gamma voltage generating device of claim 20, wherein the plurality of resistors included in the voltage difference generator have a resistance determined by a predetermined unit distribution for the plurality of distribution voltages. The gamma voltage generating device of claim 20, wherein the voltage difference selecting unit records the voltage difference between the first power voltage and the first reference voltage in a process of determining the gamma voltage in advance And outputting the recorded voltage difference to the reference voltage output unit after manufacturing a product. The gamma voltage generating device of claim 20, wherein the reference voltage output unit comprises a differential amplifier that outputs a difference between the second power voltage and a voltage output by the voltage difference selecting unit. The gamma voltage generating device of claim 19, wherein the gamma voltage generator comprises: a reference voltage dividing unit, comprising a plurality of series coupled between the second reference voltage and a reference voltage a gamma voltage selection unit that selects the plurality of gamma voltages corresponding to a predetermined gray level by using a plurality of distribution voltages distributed to the plurality of resistors; and a gamma voltage output unit And using the second reference voltage and the plurality of gamma voltages selected from the gamma voltage selection unit to output a plurality of gamma voltages corresponding to the full gray scale. The gamma voltage generating device of claim 24, wherein the gamma voltage selecting unit comprises: selecting a second gamma indicating that the gray level is higher than the first gamma voltage corresponding to the second reference voltage The first selector of voltage. The gamma voltage generating device of claim 25, wherein the gamma voltage selecting unit further comprises selecting a seventh gamma voltage as one of the lowest voltages of the plurality of gamma voltages corresponding to the full gray level. Second selector. The gamma voltage generating device of claim 26, wherein the gamma voltage selecting unit further comprises the second gamma voltage transmitted by the first selector by using a connection and by the second selector One of the seventh gamma voltages is selected to distribute the resistor to select a sixth selector of a sixth gamma voltage. The gamma voltage generating device of claim 27, wherein the gamma voltage selecting unit further comprises the second gamma voltage transmitted by the first selector by using a connection and by the sixth selector One of the sixth gamma voltages is selected to distribute the resistor to select a fifth selector of a fifth gamma voltage. The gamma voltage generating device of claim 28, wherein the gamma voltage selecting unit further comprises the second gamma voltage transmitted by the first selector by using a connection and by the fifth selector One of the fifth gamma voltages is selected to distribute the resistor to select a fourth selector of a fourth gamma voltage. The gamma voltage generating device of claim 29, wherein the gamma voltage selecting unit further comprises the second gamma voltage transmitted by the first selector by using a connection and by the fourth selector One of the fourth gamma voltages is selected to distribute the resistor to select a third selector of a third gamma voltage. The gamma voltage generating device of claim 19, further comprising: generating a reference voltage to generate a second reference voltage generator that is one of the plurality of gamma voltages for driving the plurality of pixels in cooperation with a power supply voltage. The gamma voltage generating device of claim 31, wherein a voltage difference between the first power voltage and a first reference voltage in the process of determining the gamma voltage is recorded in the first And a second reference voltage generator, wherein the second reference voltage generator generates a second reference voltage as a difference between the second power voltage and the recorded voltage difference. The gamma voltage generating device of claim 32, wherein the second reference voltage generator comprises: a first differential amplifier comprising: inputting a first input terminal of a comparison voltage and outputting one of the amplification voltages a voltage difference generator comprising: a plurality of resistors coupled in series between the amplified voltage and a ground; a voltage difference selecting unit, wherein the voltage difference generator selects a distribution voltage from the first difference The amplifier outputs the amplified voltage corresponding to the voltage difference between the first power voltage and the first reference voltage, and inputs the power distribution voltage to the second input end of the first differential amplifier; and a reference voltage output unit, The difference between the second power voltage and the amplified voltage is output as the second reference voltage. The gamma voltage generating device of claim 33, wherein the voltage difference selecting unit records the voltage difference between the first power source voltage and the first reference voltage in the process of generating the gamma voltage The amplified voltage is generated, and the recorded amplified voltage is output via the first differential amplifier after the product is manufactured. The gamma voltage generating device of claim 33, wherein the reference voltage output unit comprises one of a difference between the output voltage supplied from the outside and the amplified voltage output by the first differential amplifier. Differential amplifier. A method of generating a gamma voltage, the method comprising: driving a voltage difference between a first supply voltage of a plurality of pixels and a predetermined one of the first reference voltages in a process of predetermining the gamma voltage Recording; generating a second reference voltage as a difference between a second supply voltage for driving the plurality of pixels and a voltage difference of the recording after manufacturing a product; and generating a plurality of numbers by using the second reference voltage Gamma voltage. The method of claim 36, wherein the recorded voltage difference comprises selecting from a plurality of distribution voltages distributed to a plurality of resistors connected in series between a comparison voltage and a ground voltage. a voltage of the voltage difference between the power supply voltage and the first reference voltage. The method of claim 36, further comprising recording the first power voltage for driving the plurality of pixels and one of the predetermined ones of the first reference voltages in a process of predetermining the gamma voltage difference. The method of claim 38, further comprising generating a second reference voltage as a difference between the second power voltage for driving the plurality of pixels and the second voltage difference of the record after manufacturing a product. The method of claim 39, wherein generating the plurality of gamma voltages comprises generating the plurality of gamma voltages by using the second reference voltage and the second reference voltage. The method of claim 36, wherein generating the plurality of gamma voltages comprises: using a plurality of resistors distributed to the plurality of resistors coupled in series between the second reference voltage and a reference voltage The distribution voltage selection corresponds to the plurality of gamma voltages that predetermine the gray level; The plurality of gamma voltages corresponding to the full gray scale are generated by using the second reference voltage and the plurality of gamma voltages corresponding to the predetermined gray scale. The method of claim 41, wherein selecting the plurality of gamma voltages corresponding to the predetermined gray level comprises selecting to indicate that one gray level is higher than one of the first gamma voltages corresponding to one of the second reference voltages. Two gamma voltage. The method of claim 42, wherein selecting the plurality of gamma voltages corresponding to the predetermined gray scale comprises selecting a seventh gamma voltage as one of the plurality of gamma voltages corresponding to the full gray scale Voltage. The method of claim 43, wherein selecting the plurality of gamma voltages corresponding to the predetermined gray scale comprises selecting by using a distributed resistor connected to the second gamma voltage and the seventh gamma voltage A sixth gamma voltage. The method of claim 44, wherein the selecting the plurality of gamma voltages corresponding to the predetermined gray level comprises using a distribution between the second gamma voltage and the sixth gamma voltage The resistor selects a fifth gamma voltage. The method of claim 45, wherein the selecting the plurality of gamma voltages corresponding to the predetermined gray scale comprises using a distribution between the second gamma voltage and the fifth gamma voltage The resistor selects a fourth gamma voltage. The method of claim 46, wherein the selecting the plurality of gamma voltages corresponding to the predetermined gray level comprises using a distribution between the second gamma voltage and the fourth gamma voltage The resistor selects a third gamma voltage.