KR102102697B1 - method of driving display panel and display apparatus using the same - Google Patents

Abstract

The display panel driving method includes analyzing digital image data to select a reference grayscale value for each frame, generating at least one gamma data corresponding to the reference grayscale value, and a first analog corresponding to the reference grayscale value. Generating a second analog driving voltage smaller than the first analog driving voltage from a driving voltage, generating at least one gamma reference voltage corresponding to the second analog driving voltage and the gamma data, and the second analog And generating a gradation voltage corresponding to the driving voltage and the gamma reference voltage, and displaying an image on a display panel using the gradation voltage.

Description

Method of driving display panel and display device for performing same {method of driving display panel and display apparatus using the same}

The present invention relates to a method of driving a display panel of a display device and a display device to perform the same, and more specifically, to analyze the gradation of image data in driving the display device and optimize the driving voltage accordingly to reduce power consumption. It relates to a driving method of a display panel and a display device performing the same.

Recently, a flat panel display (FPD), which is easy to have a large area and can be thin and lightweight, is widely used as a display device, and such a flat panel display includes a liquid crystal display (LCD), a plasma display panel ( Plasma display panels (PDPs) and organic light emitting displays (OLEDs) are used.

The display device converts digital image data into analog data, such as a gradation voltage, and displays it on a display panel so that it can be viewed from a human perspective.

For example, in the case of a liquid crystal display device, the gradient of a liquid crystal molecule arrangement is changed by varying the intensity of a gradation voltage applied to the pixel electrode of the liquid crystal, and through this, the intensity of light passing through the liquid crystal is adjusted to adjust the color of the color displayed on the screen. Adjust gradation.

Therefore, the liquid crystal display panel requires a voltage of various intensities from a voltage for representing the minimum gradation to a voltage for representing the maximum gradation that the liquid crystal display panel can express for driving. Used as driving voltage (AVDD). Therefore, the analog driving voltage AVDD applied to the data driver is kept constant in order to display all the gradations that the liquid crystal display panel can express.

However, the gradation displayed on the screen does not always require the maximum gradation that can be expressed by the liquid crystal display panel, and in this case, the voltage for representing a gradation having a value greater than the gradation having the maximum value among the gradations displayed on the screen. Silver is wasted is a problem that consumes more power than necessary.

In addition, in order to prevent deterioration of the liquid crystal display panel, an inversion driving of the liquid crystal molecule arrangement is performed, and for this purpose, inversion driving to two polarities of positive polarity (+ polarity) and negative polarity (-polarity) based on the common electrode do. Therefore, when considering the positive and negative polarities, the wasted voltage is further increased.

Accordingly, the technical problem of the present invention has been devised in this regard, and the object of the present invention is to analyze the input digital image data and select an arbitrary value among grayscales displayed on a screen to a level necessary to express the selected grayscale. It is to provide a display panel driving method for driving by varying the analog driving voltage (AVDD).

Another object of the present invention is to provide a display device that performs the display panel driving method.

The display panel driving method according to an embodiment for realizing the object of the present invention includes analyzing digital image data to select a reference grayscale value of each frame, and at least one gamma data corresponding to the reference grayscale value Generating, a second analog driving voltage smaller than the first analog driving voltage from a first analog driving voltage corresponding to the reference grayscale value, at least corresponding to the second analog driving voltage and the gamma data Generating at least one gamma reference voltage, generating a grayscale voltage corresponding to the second analog driving voltage and the gamma reference voltage, and displaying an image on a display panel using the grayscale voltage.

In one embodiment of the present invention, the step of generating the second analog driving voltage generates the second analog driving voltage by adjusting the magnitude of the first analog driving voltage to a first magnitude corresponding to the reference grayscale value. In addition, the first size may be a predetermined size to generate only positive polarity grayscale voltages having a value greater than the common voltage up to a positive polarity grayscale voltage corresponding to the reference grayscale value.

In an embodiment of the present invention, the step of selecting the reference grayscale value GRYref may select the maximum grayscale value of each frame of the digital image data as the reference grayscale value GRYref.

In one embodiment of the present invention, the step of selecting the reference grayscale value (GRYref) is based on a preset threshold value of each frame of the digital image data, the number of pixels corresponding to each grayscale is the threshold value. The maximum threshold gradation value corresponding to the gradation value of the highest gradation exceeding may be selected as the reference gradation value.

In one embodiment of the present invention, the step of selecting the reference grayscale value (GRYref) sets the reference number of image quality degradation pixels per frame, and then sets the image quality degradation pixels in each frame of the digital image data. The maximum gradation value satisfying the reference number may be selected as the reference gradation value.

In one embodiment of the present invention, the step of selecting the reference grayscale value (GRYref) is to obtain a difference value between a maximum grayscale value and an average grayscale value in each frame of the digital image data, and weight the difference value. A multiplied median value may be obtained, and a value obtained by adding the average gradation value to the median value may be selected as the reference gradation value.

In one embodiment of the present invention, the weight may be varied such that the smaller the difference value between the maximum grayscale value and the average grayscale value, the larger the weight.

In one embodiment of the present invention, the step of generating the second analog driving voltage generates the second analog driving voltage by adjusting the magnitude of the first analog driving voltage to a second magnitude corresponding to the reference grayscale value. The method further includes the steps of generating a positive polarity grayscale voltage having a value greater than a common voltage up to a positive polarity grayscale voltage corresponding to the reference grayscale value, and a negative polarity grayscale voltage having a value less than the common voltage. The second analog driving voltage AVDD2 may be generated by having a predetermined size to generate only up to the negative polarity gradation voltage corresponding to the reference gradation value.

In an embodiment of the present invention, the method may further include changing a common voltage in response to the reference grayscale value GRYref.

The display device according to an embodiment for realizing another object of the present invention described above is a display panel for displaying an image, analyzes input digital image data, selects a reference gradation value for each frame, and corresponds to the reference gradation value. An image analysis unit generating at least one gamma data, a driving power conversion unit generating a second analog driving voltage smaller than the first analog driving voltage from a first analog driving voltage corresponding to the reference grayscale value, and the second The second analog driving voltage is electrically connected to the gamma reference voltage generator and the display panel, the driving power converter, and the gamma reference voltage generator to generate at least one gamma reference voltage corresponding to the analog driving voltage and gamma data. And data driving that receives an gamma reference voltage and transmits an electrical signal to the display panel. Includes wealth.

In one embodiment of the present invention, the driving power conversion unit includes a positive polarity conversion unit that generates the second analog driving voltage by adjusting the magnitude of the first analog driving voltage to a first magnitude corresponding to the reference grayscale value. In addition, the first magnitude may be characterized in that it is a predetermined size to generate only positive polarity gradation voltages corresponding to the reference gradation voltages.

In one embodiment of the present invention, the reference grayscale value GRYref may be a maximum grayscale value of each frame of the digital image data.

In one embodiment of the present invention, the reference gradation value is the gradation value of the highest gradation in which the number of pixels corresponding to each gradation exceeds the threshold based on a preset threshold value of each frame of the digital image data. It may be a maximum threshold gradation value corresponding to.

In one embodiment of the present invention, the reference gradation value is a maximum gradation value that satisfies the reference number of the image quality deterioration pixels in each frame of the digital image data after setting the reference number of image quality deterioration pixels allowed per frame. Can be

In one embodiment of the present invention, the reference grayscale value (GRYref) obtains a difference value between a maximum grayscale value and an average grayscale value in each frame of the digital image data, obtains an intermediate value obtained by multiplying the difference value with a weight, and calculates the intermediate value. It may be a value obtained by adding the average gradation value.

In one embodiment of the present invention, the weight may be varied such that the smaller the difference value between the maximum grayscale value and the average grayscale value, the larger the weight.

In one embodiment of the present invention, the driving power converter includes a negative polarity converter for generating the second analog driving voltage by adjusting the magnitude of the first analog driving voltage to a second magnitude corresponding to the reference grayscale value. The second magnitude generates positive polarity gradation voltages having a value greater than the common voltage up to the positive gradation gradation voltage corresponding to the reference gradation value, and negative polarity gradation voltages having a value less than the common voltage to the reference gradation value. It may be a predetermined size to generate only the corresponding negative polarity gradation voltage.

In one embodiment of the present invention, the display device may include a common voltage generator configured to receive a first common voltage and generate a second common voltage smaller than the first common voltage in response to the reference grayscale value.

According to a display panel driving method and a display device according to embodiments of the present invention, power consumption of a data driving unit is reduced by varying an analog driving voltage input to a data driving unit in response to a gradation value displayed on a screen, and the analog driving The loss rate of the voltage generation stage is reduced, so that the total power consumption of the power stage may be reduced.

1 is a block diagram illustrating a display device according to an exemplary embodiment of the present invention.
FIG. 2 is a graph for explaining a method of selecting a reference gradation value of the image analysis unit of FIG. 1.
FIG. 3 is a graph showing a relationship between a gradation voltage and an analog driving voltage at each gradation level for explaining a driving method of the display panel of FIG. 1.
4 is a graph for explaining a method of selecting a reference grayscale value (GRYref) of an image analysis unit of a display device according to another exemplary embodiment of the present invention.
5 is a graph for explaining a method for selecting a reference grayscale value (GRYref) of an image analysis unit of a display device according to another embodiment of the present invention.
6 is a graph for explaining a method of selecting a reference grayscale value (GRYref) of an image analysis unit of a display device according to another embodiment of the present invention.
7 is a block diagram illustrating a display device according to another exemplary embodiment of the present invention.
8 is a block diagram showing a driving power converter of FIG. 7.
FIG. 9 is a graph showing a relationship between a gradation voltage and an analog driving voltage at each gradation level for explaining a driving method of the display panel of FIG. 7.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

As described above, a liquid crystal display (LCD), a plasma display panel (PDP), an organic light emitting display (OLED), etc. may be applied to the flat panel display panel, but the present embodiment In the example, description will be made by applying a liquid crystal display (LCD).

1 is a block diagram illustrating a display device according to an exemplary embodiment of the present invention.

Referring to FIG. 1, the display device analyzes input digital image data, a display panel 10 for displaying an image, selects a reference grayscale value GRYref of each frame, and at least corresponds to the reference grayscale value GRYref. An image analysis unit 70 that generates one or more gamma data GMAdata, a driving power supply that generates a second analog driving voltage AVDD2 from a first analog driving voltage AVDD1 corresponding to the reference grayscale value GRYref Conversion unit 80, the second analog driving voltage (AVDD2) and at least one gamma reference voltage (GMAref) for generating at least one gamma reference voltage (GMAref) corresponding to the gamma data (GMAdata) and the display panel (10), the driving power converter 80 and the gamma reference voltage generator 50 are electrically connected to the display panel 10 by receiving the second analog driving voltage AVDD2 and the gamma reference voltage GMAref. To transmit electrical signals to It includes emitter driver 20.

The display device is electrically connected to the display panel 10 to sequentially activate the gate lines GL of the display panel 10, the gate driver 30, the gate driver 30 and the data driver 20 ) May include a timing controller 40 for controlling driving timing and a power supply unit 60 for supplying driving power to the driving power conversion unit 80.

The display panel 10 includes a plurality of pixels displaying an image. For example, the display panel 100 may include M * N (M and N are natural numbers) pixels. Each pixel includes a switching element TR connected to a gate line GL and a data line DL, a liquid crystal capacitor Clc and a storage capacitor Cst connected to the switching element TR. The pixels are configured in a matrix form, and the gate line GL extends parallel to the first side of the display panel 10 and is connected to the gate driver 30. The data line DL extends parallel to the second side of the display panel 10 and is connected to the data driver 20. The gate line GL and the data line DL may be composed of M and N numbers depending on the number of pixels.

When a gate-on pulse is supplied to the gate line GL, digital image data is converted into the gradation voltage, which is an analog data voltage, by the data driver 20 and supplied to the data line DL. The gradation voltage is charged in the liquid crystal capacitor Clc. To this end, a gate electrode of the switching element TR is connected to the gate line GL, a source electrode is connected to the data line DL, and a drain electrode is a pixel electrode and the storage of the liquid crystal capacitor Clc. It is connected to the first electrode of the capacitor Cst. The common voltage Vcom is supplied to the common electrode of the liquid crystal capacitor Clc, and the gradation voltage is supplied to the pixel electrode. The gradation voltage is supplied to the first electrode of the storage capacitor Cst, and the storage voltage Vst is supplied to the second electrode. For example, the storage voltage Vst may be the same as the common voltage Vcom. The storage capacitor Cst serves to maintain the voltage of the liquid crystal capacitor Clc by charging the gradation voltage applied from the data line DL when the switching element TR is turned on.

When the switching element TR is turned on by a gate-on pulse applied to the gate line GL to form a channel between the source electrode and the drain electrode, the gradation voltage on the data line DL is the liquid crystal capacitor. The liquid crystal molecules are supplied to the pixel electrode of (Clc), and the liquid crystal molecules are changed in order by the potential difference between the gradation voltage applied to the pixel electrode and the common voltage (Vcom) applied to the common electrode, so that the incident light transmittance is adjusted. It expresses the gradation.

The image analysis unit 70 analyzes digital image data to construct an image of each frame, examines a gradation value of a unit pixel represented by the pixel, selects a reference gradation value (GRYref), and selects the reference gradation value (GRYref). ) Corresponding to at least one or more of the gamma data (GMAdata) is generated. The gamma data GMAdata may be generated in the form of digital data.

The reference grayscale value GRYref is a reference value for determining the magnitude of the second analog driving voltage AVDD2. Hereinafter, 256 gradations from 0 to 255 gradations can be expressed, and a description will be given based on a display device operating in a normally black mode. In this case, in order to express 255 gradations, the largest analog driving voltage (AVDD) is required. Therefore, if an image of a frame contains only 192 gradations, it can be expressed with a relatively low driving voltage. Therefore, the reference grayscale value GRYref is a variable necessary to determine the size of the analog driving voltage AVDD required to represent a screen. A detailed reference grayscale value (GRYref) selection method will be described separately below.

The gamma data GMAdata is used to maintain the voltages of the gamma reference voltages GMAref corresponding to the gray scales below the reference gray value GRYref. The voltage of the gamma reference voltages GMAref corresponding to the gray level exceeding the reference gray level value GRYref may be the same as the voltage of the second analog driving voltage AVDD2.

The driving power conversion unit 80 receives the first analog driving voltage AVDD1 as a basic from the power supply unit 60 and receives the reference grayscale value GRYref from the image analysis unit 70. The first analog driving voltage AVDD1 is a basic analog driving voltage necessary for expressing 255 gradations. When the reference grayscale value GRYref is smaller than 255 grayscales, the second analog driving voltage AVDD2 is generated correspondingly. The generated second analog driving voltage AVDD2 is transmitted to the analog circuit of the data driving unit 20 and the gamma reference voltage generating unit 50.

The gamma reference voltage generator 50 generates the gamma reference voltage GMAref, which is a reference for gamma correction in consideration of human visual recognition characteristics, and transmits the gamma reference voltage GMAref to the data driver 20. The gamma reference voltage GMAref has a value between the first analog driving voltage AVDD1 and the low level analog driving voltage AVSS (not shown). The low-level analog driving voltage AVSS (not shown) may be, for example, a value of zero. The low level analog driving voltage AVSS (not shown) may be, for example, a ground voltage. The gamma reference voltage GMAref may be generated with a number equal to or less than the number of gradation voltages. The gamma reference voltage GMAref is divided into a positive polarity gamma reference voltage corresponding to a positive polarity grayscale voltage and a negative polarity gamma reference voltage corresponding to a negative polarity grayscale voltage based on the common voltage Vcom. In the embodiment according to FIG. 1, the gamma reference voltage generation unit 50 generates all gamma reference voltages (GMAref) corresponding to 0 to 255 gray levels with respect to the negative polarity gamma reference voltage, and the positive gamma reference voltage For this, only the gamma reference voltage GMAref corresponding to the reference grayscale value GRYref is generated. The gamma reference voltage GMAref corresponding to the gradation thereafter may be generated with a voltage equal to the maximum value of the generated positive polarity gamma reference voltage.

The timing control unit 40 is a control unit for controlling the driving timing of the gate driving unit 30 and the data driving unit 20, digital image data, a vertical synchronization signal (Vsync) for vertical synchronization, and horizontal synchronization for horizontal synchronization. Control signals such as a signal (Hsync), a clock signal (CLK) for synchronization, and a data enable signal (DE) are received.

Based on the control signal, the gate driver 30 includes a vertical synchronization start signal instructing the start of the output of the gate-on pulse, a gate clock signal for controlling the output timing of the gate-on pulse, and an output in which limits the width of the gate-on pulse. Able traffic light is transmitted. In addition, the data driving unit 20 transmits the digital image data appropriately so as to be processed by the data driving unit 20, and a horizontal synchronization start signal instructing to start inputting the changed digital image data, the data line A load signal to apply the corresponding gradation voltage to (DL), an inversion signal to invert the polarity of the gradation voltage with respect to the common voltage Vcom, and a data clock signal are transmitted.

The data driver 20 receives the changed digital image data and transmits a gradation voltage corresponding to each pixel to the data line DL. To this end, the data driver 20 sequentially operates sampling cells for sampling the image data of each column of the changed digital image data in synchronization with the horizontal synchronization start signal, and sequentially operates each cell of the sampling latch according to the horizontal synchronization start signal. When the sampling is completed by using the shift register, the time of one row is transmitted, the holding latch receiving all image data of the sampling latch, and the image data transferred to the holding latch are transferred from the gamma reference voltage generator 50 And a digital-to-analog converter generating the gray level voltage based on the received gamma reference voltage GMAref and an output buffer outputting the gray level voltage to the pixel. The second analog driving voltage AVDD2 is applied to the digital-to-analog converter and output buffer.

The gate driver 30 applies the voltage to each of the gate lines GL in sequence according to the vertical synchronization start signal, the gate clock signal, and the output enable signal received from the timing controller 40 to switch the switching element ( TR) is turned on. To this end, a shift register for sequentially transmitting signals from the top to the bottom of the gate line GL, a level shifter for generating a gate-on voltage that is a high voltage for turning on a pixel, and the gate-on voltage are quickly applied to the gate line GL. It consists of a buffer for application.

The power supply unit 60 supplies the first analog driving voltage AVDD1 to the driving power conversion unit 80.

The common voltage Vcom is a voltage applied to the common electrode and is a voltage that is a reference for inversion driving to prevent deterioration of the liquid crystal. In general, it is set to an intermediate value between the first analog driving voltage AVDD1 and the low-level analog driving voltage AVSS (not shown). Accordingly, the positive gradation voltage has a value between the common voltage Vcom and the first analog driving voltage AVDD1, and the negative polarity gradation voltage is the common voltage from the low-level analog driving voltage AVSS (not shown). (Vcom).

FIG. 2 is a graph for explaining a method for selecting a reference grayscale value (GRYref) of the image analysis unit 70 of FIG. 1.

Referring to FIG. 2, the graph of FIG. 2 shows the number of pixels for each gray level based on one frame of the digital image data, and in the embodiment of FIG. 1, the reference gray level value GRYref is the number of the digital image data. It can be the maximum gradation value of each frame.

FIG. 3 is a graph showing a relationship between a gradation voltage and an analog driving voltage at each gradation level for explaining a driving method of the display panel of FIG. 1.

Referring to FIG. 3, the graph of FIG. 3 shows the magnitude of the gradation voltage for each gradation level, and the upper side represents the magnitude of the positive polarity gradation voltage and the lower side represents the magnitude of the negative polarity gradation voltage based on the common voltage Vcom. . In addition, a portion indicated by a dotted line expressed in a gradation greater than or equal to the reference gradation value (GRYref) represents the gradation voltage required when all 255 gradations are included, and the required driving voltage is the magnitude of the first analog driving voltage AVDD1. It is marked together. According to the present embodiment, since the magnitude of the positive polarity grayscale voltage corresponding to the reference grayscale value GRYref is not required, the second necessary for generating the positive polarity grayscale voltage corresponding to the reference grayscale value GRYref. The analog driving voltage AVDD2 may be generated with a lower value than the first analog driving voltage AVDD1.

According to this embodiment, the power consumption of the data driving unit is reduced by varying the analog driving voltage input to the data driving unit to the second analog driving voltage smaller than the first analog driving voltage in response to the reference grayscale value. The loss rate of the analog driving voltage generation stage is reduced, so that the total power consumption of the power stage may be reduced.

4 is a graph for explaining a method of selecting a reference grayscale value (GRYref) of an image analysis unit of a display device according to another exemplary embodiment of the present invention.

The display panel driving method and the display device according to the present embodiment are substantially the same as the display panel driving method and the display device described with reference to FIGS. 1 to 3, except for selecting the reference grayscale value (GRYref). The same reference numerals are used for the same or similar components, and overlapping descriptions are omitted.

1, 3 and 4, the reference grayscale value GRYref may be a maximum threshold grayscale value of each frame of the digital image data. The maximum threshold grayscale value refers to a grayscale value of the highest grayscale in which the number of pixels corresponding to each grayscale exceeds the threshold based on a preset threshold. For example, the threshold may be a fixed value. Alternatively, the threshold may be a variable value.

5 is a graph for explaining a method for selecting a reference grayscale value (GRYref) of an image analysis unit of a display device according to another embodiment of the present invention.

The display panel driving method and the display device according to the present embodiment are substantially the same as the display panel driving method and the display device described with reference to FIGS. 1 to 3, except for selecting the reference grayscale value (GRYref). The same reference numerals are used for the same or similar components, and overlapping descriptions are omitted.

1, 3, and 5, the reference grayscale value GRYref is a maximum grayscale value that satisfies this in each frame of the digital image data after setting the number of allowed deterioration pixels per frame. You can. For example, if the number of deteriorated pixels of the image quality is K, the number of pixels from the upper gradation step per frame may be counted to select the gradation when K is satisfied as the reference gradation value (GRYref). Here, K is a natural number. For example, the number of deteriorated pixels of the picture quality may be a fixed value. Alternatively, the number of deteriorated pixels of the image quality may be a variable value.

6 is a graph for explaining a method of selecting a reference grayscale value (GRYref) of an image analysis unit of a display device according to another embodiment of the present invention.

The display panel driving method and the display device according to the present embodiment are substantially the same as the display panel driving method and display device described with reference to FIGS. 1 and 3, except for selecting the reference grayscale value GRYref. The same reference numerals are used for the same or similar components, and overlapping descriptions are omitted.

1, 3, and 6, the reference grayscale value GRYref obtains a difference value between a maximum grayscale value and an average grayscale value in each frame of the digital image data, and a weight alpha (α) ) To obtain a median value multiplied by adding the median value to the average grayscale value. The alpha (α) is a value between 0 and 1.

In one embodiment of the present invention, the alpha (α) may be variably adjusted according to the magnitude of the difference between the maximum grayscale value and the average grayscale value. More specifically, the smaller the difference value, the larger the alpha (α).

7 is a block diagram illustrating a display device according to another exemplary embodiment of the present invention. 8 is a block diagram showing the driving power converter 80 of FIG. 7. FIG. 9 is a graph showing a relationship between a gradation voltage and an analog driving voltage at each gradation level for explaining a driving method of the display panel of FIG. 7.

The display panel driving method and the display device according to the present exemplary embodiment further include a common voltage generator 90, and the driving power converter 80 includes a positive polarity converter and a negative polarity converter, FIG. 1. Since the display panel driving method and display apparatus described with reference to FIG. 3 are similar in configuration, the same reference numerals are used for the same or similar components, and overlapping descriptions are omitted. Differences will be mainly described below.

7 to 9, the display device analyzes input digital image data, a display panel 10 for displaying an image, selects a reference grayscale value (GRYref) of each frame, and selects the reference grayscale value (GRYref). The image analysis unit 70 generates at least one gamma data GMAdata corresponding to the third analog driving voltage AVDD3 from the first analog driving voltage AVDD1 corresponding to the reference grayscale value GRYref. A driving power converter 80 for generating, a gamma reference voltage generator 50 for generating at least one gamma reference voltage GMAref corresponding to the third analog driving voltage AVDD3 and gamma data GMAdata. , A common voltage generator 90, a data driver 20, a gate driver 30, a timing controller 40, and the gamma reference that generates a second common voltage Vcom2 corresponding to the reference grayscale value GRYref. Voltage generator 50, data driver 20 A power supply 60 for supplying a driving power to a common voltage generating unit 90. The

The image analysis unit 70 selects the reference grayscale value GRYref and transmits it to the driving power conversion unit 80 and the common voltage generation unit 90 in the same manner as described with reference to FIG. 2. The gamma data GMAdata is used to modify the gamma reference voltage GMAref corresponding to the variable third analog driving voltage AVDD3 and the second common voltage Vcom2. The gamma data GMAdata may be generated in the form of digital data. Alternatively, the image analysis unit 70 selects a reference grayscale value GRYref by using any one of the methods described with reference to FIGS. 4 to 6 to drive the power conversion unit 80 and the common voltage generation unit (90).

The driving power conversion unit 80 receives the first analog driving voltage AVDD1 which is the basic from the power and receives the reference grayscale value GRYref from the image analysis unit 70. The first analog driving voltage AVDD1 is the same as described in FIG. 1.

Referring to Figure 8, The operation and internal configuration of the driving power converter 80 in the embodiment described with reference to FIGS. 1 and 3 are included as a positive polarity converter 81, and a negative polarity converter 82 is further included.

Referring to Figure 9, The graph of FIG. 9 is a graph showing the magnitude of the gradation voltage at each gradation level. In the present exemplary embodiment, the third analog driving voltage AVDD3 is the first analog driving because a gray level voltage is not required for a gray level higher than the reference gray level value GRYref for not only the positive polarity gray level voltage but also the negative polarity gray level voltage. In addition to the voltage AVDD1, a value lower than the second analog driving voltage AVDD2 may be generated.

The negative polarity converter 82 is a conceptual configuration for considering the negative polarity gradation voltage when generating the third analog driving voltage AVDD3, and is necessarily separated from the positive polarity converter 81 It doesn't have to be.

The common voltage generator 90 receives the basic first common voltage Vcom1 from the power supply unit 60 to generate the second common voltage Vcom2 corresponding to the reference grayscale value GRYref. Transfer to the common electrode of the display panel 10. For example, the second common voltage Vcom2 may have a size of 1/2 of the third analog driving voltage AVDD3.

The gamma reference voltage generation unit 50 generates not only the positive polarity gamma reference voltage but also the negative polarity gamma reference voltage from 0 gradation to a gamma reference voltage GMAref corresponding to the reference gradation value GRYref. The positive and negative polarity gamma reference voltages corresponding to the gray scales after the reference grayscale value GRYref may be generated with voltages equal to the maximum value of the generated positive polarity gamma reference voltage and the maximum value of the negative polarity gamma reference voltage, respectively. have. In addition, in the present embodiment, since the second common voltage Vcom2, which is the reference of the gamma reference voltage GMAref, varies according to the reference grayscale value GRYref, the gamma reference voltage GMAref is also shown in FIGS. Unlike the gamma reference voltage (GMAref) in 6, it is variable according to the reference grayscale value (GRYref).

According to this embodiment, the power consumption of the data driving unit is reduced by varying the analog driving voltage input to the data driving unit to the third analog driving voltage smaller than the first analog driving voltage in response to the reference grayscale value. The loss rate of the analog driving voltage generation stage is reduced, so that the total power consumption of the power stage may be reduced.

In this embodiment, the liquid crystal display panel of the liquid crystal display device has been exemplarily described, but the display panel module of the present invention may be used in other flat panel display panel devices, for example, organic light emitting display devices.

Although described with reference to the above embodiments, those skilled in the art understand that various modifications and changes can be made to the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. Will be able to.

According to the display panel driving method and the display device according to the embodiments for realizing the above object of the present invention, the power consumption of the data driving unit is varied by varying the analog driving voltage input to the data driving unit in response to the gradation value displayed on the screen. This is reduced, the loss rate of the analog driving voltage generation stage is reduced, the total power consumption of the power stage can be reduced.

10: display panel 20: data driver
30: gate driver 40: timing control
50: gamma reference voltage generation unit 60: power supply unit
70: image analysis unit 80: driving power conversion unit
81: positive polarity conversion unit 82: negative polarity conversion unit
90: common voltage generator AVDD1: first analog drive voltage
AVDD2: Second analog driving voltage AVDD3: Third analog driving voltage
Vcom: Common voltage Vcom1: First common voltage
Vcom2: Second common voltage GMAdata: Gamma data
GMAref: gamma reference voltage GRYref: reference gradation value
DL: Data line (DL) GL: Gate line (GL)
TR: Switching element Clc: Liquid crystal capacitor
Cst: storage capacitor

Claims (18)

Analyzing digital image data using an image analysis unit disposed in the timing control unit and selecting a reference grayscale value of each frame;
Generating at least one gamma data corresponding to the reference grayscale value;
Generating a second analog driving voltage smaller than the first analog driving voltage from a first analog driving voltage in response to the reference gradation value using a driving power converting unit disposed outside the timing controller;
Generating at least one gamma reference voltage corresponding to the second analog driving voltage and the gamma data;
Generating a gradation voltage corresponding to the second analog driving voltage and the gamma reference voltage; And
And displaying an image on a display panel using the gradation voltage,
The generating of the second analog driving voltage is
The second analog driving voltage is generated by adjusting the magnitude of the first analog driving voltage to a first magnitude corresponding to the reference gradation value.
The first size is a size set in advance to generate only positive gradation voltages having a value greater than the common voltage up to the positive gradation voltage corresponding to the reference gradation value,
The step of selecting the reference gradation value is
i) Based on a preset threshold value of each frame of the digital image data, the maximum threshold grayscale value corresponding to the highest grayscale value in which the number of pixels corresponding to each grayscale exceeds the threshold value is used as a reference grayscale value. Select, or
ii) after setting the reference number of permissible deterioration pixels per frame, select the maximum gradation value that satisfies the reference number of deterioration pixels in each frame of the digital image data as the reference gradation value,
iii) The difference between the maximum grayscale value and the average grayscale value in each frame of the digital image data is obtained, an intermediate value obtained by multiplying the difference value with a weight is obtained, and the intermediate value is added to the average grayscale value. A method of driving a display panel, characterized in that it is selected as a grayscale value. delete delete delete delete delete The method of claim 1, wherein the weight
A method of driving a display panel, characterized in that the smaller the difference value between the maximum grayscale value and the average grayscale value, the greater the weight. The method of claim 1, wherein the step of generating the second analog driving voltage
The method further includes generating the second analog driving voltage by adjusting the magnitude of the first analog driving voltage to a second magnitude corresponding to the reference grayscale value.
The second magnitude generates the positive polarity grayscale voltages having a value greater than the common voltage up to the positive polarity grayscale voltage corresponding to the reference grayscale value, and the negative polarity grayscale voltages having a value less than the common voltage. A method of driving a display panel, characterized in that it has a predetermined size in order to generate only the negative polarity gradation voltage corresponding to the gradation value. The method of claim 8, comprising changing the common voltage in response to the reference grayscale value. A display panel for displaying an image;
An image analysis unit that analyzes the input digital image data to select a reference grayscale value of each frame and generates at least one gamma data corresponding to the reference grayscale value;
A driving power converter configured to generate a second analog driving voltage smaller than the first analog driving voltage from the first analog driving voltage in response to the reference grayscale value;
A gamma reference voltage generator configured to generate at least one gamma reference voltage corresponding to the second analog driving voltage and gamma data;
A data driver that is electrically connected to the display panel, the driving power converter, and the gamma reference voltage generator to receive the second analog drive voltage and gamma reference voltage and transmit an electrical signal to the display panel; And
It includes a timing control unit for controlling the driving timing of the data driving unit,
The image analysis unit is disposed in the timing control unit,
The driving power converter is disposed outside the timing controller,
The driving power converter
And a positive polarity converter configured to generate the second analog driving voltage by adjusting the magnitude of the first analog driving voltage to a first magnitude corresponding to the reference grayscale value.
The first size is a size set in advance to generate only positive gradation voltages having a value greater than the common voltage up to the positive gradation voltage corresponding to the reference gradation value,
The reference gradation value is
i) the maximum threshold gradation value corresponding to the gradation value of the highest gradation in which the number of pixels corresponding to each gradation exceeds the threshold value based on a preset threshold value of each frame of the digital image data,
ii) a maximum gradation value that satisfies the reference number of the image quality deterioration pixels in each frame of the digital image data after setting the reference number of image quality deterioration pixels allowed per frame, or
iii) obtaining the difference between the maximum grayscale value and the average grayscale value in each frame of the digital image data, obtaining a median value multiplied by the weight of the difference, and adding the average grayscale value to the median value Display device. delete delete delete delete delete The method of claim 10, wherein the weight
The smaller the difference value between the maximum gradation value and the average gradation value is, the display device is characterized in that the weight is variable to increase. 11. The method of claim 10, The drive power conversion unit
And a negative polarity converter configured to generate the second analog driving voltage by adjusting the magnitude of the first analog driving voltage to a second magnitude corresponding to the reference grayscale value.
The second magnitude generates only the positive gradation voltages having a value greater than the common voltage up to the positive gradation voltage corresponding to the reference gradation value, and the negative gradation voltages having a value less than the common voltage are the reference gradation. Display device characterized in that it has a predetermined size to generate only a negative polarity gradation voltage corresponding to a value. The method of claim 17,
And a common voltage generator configured to receive a first common voltage and generate a second common voltage smaller than the first common voltage in response to the reference grayscale value.

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