CN101149900A - Drive method for reducing plane display power consumption - Google Patents

Abstract

The method for reducing the power consumption of a plane display includes: judging pixel RGB grey scale values and converting them into three exciting values of X,Y,Z which are then converted into three values of L*,a*,b* and determining the three values of L*',a*',b* ' in a receptive range of color difference, in which the color difference between L*',a*',b* ' and L*,a*,b* is in the receptive range of color difference, at last converting the values of L*',a*',b* ' into three exciting values of X',Y',Z'which are then converted into R'G'B'grey-scale values. Advantage: effectively reduced power-consumption of blue light and integral panel, prolonged service-life of blue light and integral device.

Description

Driving method for reducing power consumption of flat panel display

Technical Field

The present invention relates to an operating method, and more particularly, to an operating method of an organic light emitting diode.

Background

The basic structure of an organic light-emitting diode (OLED) is a sandwich structure formed by connecting a thin and transparent Indium Tin Oxide (ITO) with semiconductor characteristics to the positive electrode of a power supply, and adding another metal cathode. The whole structural layer includes: a Hole Transport Layer (HTL), an Emission Layer (EL), and an Electron Transport Layer (ETL). When the power is supplied to a proper voltage, the positive holes and the cathode electrons combine in the light-emitting layer to generate light, which generates three primary colors of red, green, and blue depending on the composition, constituting a basic color. The OLED has become a next-generation flat panel display due to its self-light emitting property, high visibility and brightness, and superior conditions of fast response, light weight, thin thickness, simple structure, and low cost.

However, the lifetime of the light-emitting material often limits the application range of the OLED, especially on the blue light material, the lifetime is far lower than that of the red and green light materials, so how to effectively improve the lifetime of the OLED becomes a pursued goal.

Disclosure of Invention

It is therefore an object of the present invention to solve the above problems. The power consumed by the red, green and blue light is saved by adjusting the color gray scale value within the range of color difference which can not be identified by human eyes, and the service life of the OLED is further prolonged.

To achieve the above object, the present invention provides a method for reducing power consumption, the method at least comprises the following steps: firstly, the RGB gray level value of the pixel is determined and converted into X, Y and Z tristimulus values, and then the X, Y and Z tristimulus values are converted into L ^* Value a ^* Value andb ^* the value of L is determined within the range of the set acceptable color difference value ^* ' value, a ^* ' value and b ^* ' value, wherein the L ^* ' value, a ^* ' value and b ^* ' value with the L ^* Value a of ^* Value and b ^* The color difference between the values is within the acceptable color difference value range,finally converting the L ^* Value of a ^* ' value and b ^* ' values are X ', Y ', Z ' tristimulus values and converted to R ' G ' B ' gray scale values.

In one embodiment, the method further comprises calculating a power saving consumption of the pixel using the R ' G ' B ' gray scale value relative to the RGB gray scale value, repeating the above steps to obtain a maximum power saving consumption R ' G ' B ' gray scale value within the acceptable color difference range, and finally driving the pixel with the maximum power saving consumption R ' G ' B ' gray scale value.

The method as described above, wherein the X, Y, Z tristimulus values are converted to L using the CIE1976LAB system ^* Value a ^* Value and b ^* The value is obtained.

The method as described above, wherein the L ^* Value sum L ^* ' value denotes the psychological lightness, a ^* Value b of ^* Value a of ^* ' value and b ^* The' value is the psycho-chromatic.

The method as described above, wherein L ^* Value of a ^* ' value and b ^* ' value and the L ^* Value a of ^* Value with b ^* The color difference between the values is [ (Delta L) ^* ) ² +(Δa ^* ) ² +(Δb ^* ) ² ] ^1/2 Wherein Δ L ^* ＝L ^* ’-L ^* ，Δa ^* ＝a ^* ’-a ^* And Δ b ^* ＝b ^* ’-b ^* 。

The method as above, wherein the acceptable color difference value ranges from 3 to 6.

The method as described above, whereinDetermining L ^* Value of a ^* ' value and b ^* The step of' value further comprises: reduction of L ^* Value to obtain L ^* ' value; rise b ^* To obtain b ^* ' value; and decrease a ^* Value to obtain a ^* ' value.

The method as described above, wherein X represents the red primary color, Y represents the green primary color, and Z represents the blue primary color.

In summary, the method of the present invention can effectively reduce the power consumption of blue light to increase the lifetime of blue light, and effectively reduce the power consumption of the whole panel to improve the overall lifetime.

Drawings

FIG. 1 is a flowchart illustrating a method for adjusting a color gray scale according to an embodiment of the invention.

FIG. 2 shows the adjustment of L according to a preferred embodiment of the present invention ^* Value of a ^* Value, b ^* ' flow chart of values.

Wherein the reference numerals are as follows:

101 to 107 and 201 to 203: step (ii) of

Detailed Description

According to the invention, the power consumed by the red, green and blue light is saved by adjusting the color gray scale value within the range of color difference which can not be identified by human eyes, so that the service life of the OLED is prolonged.

FIG. 1 is a flow chart for adjusting color gray scale according to a preferred embodiment of the present invention. In step 101, the gray scale values of RGB are determined. The gray scale values of the primary red, green and blue (RGB) are then mathematically converted to X, Y, and Z tristimulus values in step 102, where X represents the primary red color, Y represents the primary green color, and Z represents the primary blue color, which are not physically true colors, but rather fictional hypothetical colors. The conversion matrix used to convert the RGB grayscale values to the X, Y, Z tristimulus values is as follows:

[X Y Z]＝[r g b][M]

next, in step 103, to further refine and unify the color evaluation method, the color space and its associated color difference formula, i.e., CIE1976LAB (or L), were recommended by CIE in 1976 ^* a ^* b ^* System), converting the X, Y and Z tristimulus values. The conversion formula is as follows:

wherein X, Y, Z are the tristimulus values of the object; x ₀ 、Y ₀ 、Z ₀ Tri-stimulus values for CIE standard illuminant; l is ^* Representing a mental lightness; a is ^* 、b ^* Is psychochromatic, wherein a ^* Is the red and green axis, b ^* Is a yellow-blue axis. Wherein, + a ^* Indicating a red bias, -a ^* Indicates that the color is biased to green and + ^* b represents a bias towards yellow, -b ^* Indicating a blue bias, the lightness of the color being L ^* Expressed in percentage.

Next, in steps 104 and 105, the process of the present invention fine-tunes the original L ^* 、a ^* 、b ^* To L ^* ’、 a ^* ’、b ^* ' and calculate L ^* ’、a ^* ’、b ^* ' with original L ^* 、a ^* 、b ^* The color difference between the two is used to find the L which consumes the least power within the range of the color difference which can not be identified by human eyes ^* ’、a ^* ’、b ^* ' value, and replacing the original L with this value ^* 、a ^* 、b ^* . Wherein the color difference means that the difference in color perception of two colors is numerically expressed. If two color samples are according to L ^* 、a ^* 、b ^* And calibrating the color, and calculating the total color difference delta E ab and the individual color differences by the following formulas:

lightness difference: Δ L ^* ＝L ^* ’-L ^*

The chroma difference is as follows: Δ a ^* ＝a ^* ’-a ^* ，Δb ^* ＝b ^* ’-b ^*

Total color difference: Δ E ab = [ (Δ L) ^* ) ² +(Δa ^* ) ² +(Δb ^* ) ² ] ^1/2

Δ Ε ab may specify what is tolerable in human perception. The color effect within the range of different Δ Ε ab is different, wherein:

Δ E ab = 1.6-3.2, and the human eye does not substantially distinguish between colors.

Δ Ε ab = 3.2-6.5, which the professionally trained printer master can distinguish from, most people still feel the same color.

Δ Ε ab = 6.5-13, the color difference is already discriminable, but the hue itself remains the same.

Δ E × ab =13 to 25, it was confirmed that the color tone expression is different, but the subordinate color category can be identified.

Δ Ε ab, above 25, represents another different color.

The acceptable adjustment range set by the present invention is required to meet the requirement that the color difference before and after adjustment can not be identified by human eyes, so the searched L ^* ’、a ^* ’、b ^* ' with original L ^* 、a ^* 、b ^* The range of chromatic aberration (Δ Ε ab) between is intended to fall between 3 and 6.

Due to independent adjustment of L ^* Value a ^* Value b ^* The values, or any two or three of them, are adjusted, and there will be different color difference effects in vision. Therefore, according to the adjusting method of the preferred embodiment of the present invention, since human eyes have a strong sense of brightness (L) ^* ) The adjustment is carried out by adopting +/-0.5, +/-1 and so on. And the chroma (a) ^* 、b ^* ) The adjustment of (2) is carried out by analogy with + -1, + -2 and so on. To find out the L for saving the maximum power on the premise of conforming to the color difference which can not be identified by human eyes ^* Value of a ^* Value, b ^* ' value.

Then, in step 106, L is mathematically processed ^* ' value, a ^* Value, b ^* 'values are converted to X', Y ', Z' tristimulus values. And in step 107, converting the tri-stimulus values X ', Y ' and Z ' into R ' G ' B ' gray scale values by a mathematical method, and replacing the original RGB gray scale values with the R ' G ' B ' gray scale values. Finally, in step 108, the power consumed by the R ' G ' B ' gray scale values and the percentage of power saved compared to the power consumed by the original RGB gray scale values are calculated. Accordingly, the gray level value of R ' G ' B ' with the largest percentage of power saving is searched by comparison.

According to the invention, the adjustment is carried out on the premise of not influencing the color difference of vision, so that the displayed image has no difference on the feeling of human eyes, the power consumption of the whole panel can be effectively reduced, and the service life of the whole panel is prolonged.

In the preferred embodiment, for a single pixel with the same brightness of 255 grayscales, the most consumed blue power (0.00816 mW), the second most red (0.00456 mW) and the least green (0.00276 mW) are considered, so that the blue grayscales are preferably reduced when adjusting Lab.

Referring to fig. 2, a flow chart of the adjustment according to the preferred embodiment of the invention is shown. First, in step 201, Δ E ab is set to be less than 4, i.e., L ^* Value a ^* Value b ^* The adjustment range where the value is acceptable is such that the change in the color difference (Δ Ε ab) before and after the adjustment is less than 4. Then L is decreased in step 202 ^* Value due to L ^* The values represent the brightness, i.e. the perception most perceptible to the human eye, and only L ^* The value is reduced to reduce the overall power consumption. Finally, in step 203, adjust b ^* Value, in order to reduce the consumption of blue light, therefore b is to be ^* The value increases. Finally adjusting a ^* The value of a, likewise in consideration of the overall power, will be ^* The reduction in value can effectively reduce the overall power consumption.

In summary, the current OLED blue light material has the lowest lifetime, the highest red light order and the highest green light, and by applying the method, not only can the power consumed by the blue light be effectively reduced to increase the lifetime of the blue light, but also the power consumed by the whole panel is effectively reduced to improve the overall lifetime.

Although the present invention has been described with reference to the preferred embodiments, it should be understood that various changes and modifications can be made therein by those skilled in the art without departing from the spirit and scope of the invention.

Claims (8)

1. A method for reducing power consumption, the method comprising:

judging the RGB gray-scale value of the pixel;

converting the RGB gray scale value into X, Y and Z tristimulus values;

converting the three stimulation values of X, Y and Z into a value of L, a and b;

setting an acceptable color difference value;

determining a value of L, a, and b, wherein the color difference between the value of L, a, b and the value of L, a, b falls within the acceptable range of color difference values;

converting the L, a and b values into X ', Y ' and Z ' tristimulus values; and

converting the tri-stimulus values of X ', Y' and Z 'into grey scale values of R' G 'B'.

2. The method of claim 1, further comprising:

calculating the R ' G ' B ' gray scale value for the pixel to save power consumption relative to using the RGB gray scale value for the pixel;

repeatedly executing the steps of claim 1 within the acceptable color difference value range to obtain the R ' G ' B ' gray scale value with the maximum power consumption saving; and

the pixel is driven by the R ' G ' B ' gray scale value which can save the maximum power consumption.

3. The method of claim 1, wherein the X, Y, Z tristimulus values are converted to L, a, and b values using the CIE1976LAB system.

4. The method of claim 1, wherein the values of L and L' represent psychological lightness, the values of a, b, a and b being psychological chroma.

5. The method of claim 1, wherein the difference in color between the L, a, and b values and the L, a, and b values is [ (Δ L) ] ² +(Δa*) ² +(Δb*) ² ] ^1/2 Wherein Δ L = L × L, Δ a × = a × a, and Δ b × = b × b.

6. The method of claim 1, wherein the acceptable color difference value ranges from 3 to 6.

7. The method of claim 1, wherein the step of determining the values of L, a and b further comprises:

reducing the L value to obtain a L value;

increasing b to obtain b; and

and reducing the a value to obtain the a' value.

8. The method of claim 1, wherein X represents a red primary color, Y represents a green primary color, and Z represents a blue primary color.

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