JP2010211098A - Image driving method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image driving method that reduces power consumption and characteristic deterioration by appropriately reducing luminance while paying attention to saturation of a display color. <P>SOLUTION: The image driving method includes the steps of: setting a high saturation area having high saturation of a display color displayed on a display; determining whether display data displayed on the display exists in the high saturation area; and controlling so as to reduce luminance when the display data exists in the high saturation area. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image driving method capable of reducing power consumption by performing luminance control in a display.

  Conventionally, in a luminance control method for an organic EL display, a luminance integrated value is calculated for each screen based on a video input signal, and the amplitude of the video input signal is controlled based on the calculated luminance integrated value. There is one that supplies a video signal to an organic EL display (for example, see Patent Document 1).

JP 2003-255901 A

  By the way, in the chromaticity diagram (one of the color standards by the International Commission on Illumination (CIE)), C (cyan) exists in the diagonal of R (red), and M (in the diagonal of G (green). Magenta) and Y (yellow) is present at the diagonal of B (blue). In addition, in the case of a panel having a pixel configuration of RGBW, it can be seen that the power consumption is high in a pure color with high saturation when the power consumption standardized in W (white) is seen. Also, in both the RGB and RGBW panels with pixel configurations, the power consumption of Y (yellow), C (cyan), and M (magenta) tends to be large. In particular, in the case of RGBW, power consumption is 2.5 times or more in Y (yellow), C (cyan), and M (magenta) compared to W (white). Power consumption control cannot be performed.

  As described above, appropriate luminance control is not performed for representative colors (R, G, B, Y, C, and M) with high saturation. Deterioration rate is fast and tends to burn. In addition, in order to display a color with high saturation, it is necessary to prepare a power source with higher capability, which increases power consumption and cost.

  The present invention has been made in view of the above-described points, and an image driving method capable of reducing power consumption and characteristic deterioration is obtained by paying attention to the saturation of display colors and appropriately reducing luminance. This is the issue.

  The image driving method according to the present invention includes a setting step of setting a high saturation region having a high saturation of display colors displayed on the display, and whether or not the display data to be displayed on the display display is present in the high saturation region. And a luminance control step of controlling to reduce the luminance when the display data is present in the high saturation region.

  According to the present invention, it is possible to provide a driving method capable of reducing power consumption and reducing the speed of characteristic deterioration while suppressing a rapid increase in power consumption due to highly saturated data. The use period can be extended and energy can be used effectively.

It is a chromaticity diagram explaining the example of a setting of the 1st high saturation area | region which concerns on this invention, and is a figure which shows the case where a pixel structure is RGBW. It is a chromaticity diagram explaining the example of a setting of the 1st high saturation area | region which concerns on this invention, and is a figure which shows the case where a pixel structure is RGB. It is a chromaticity diagram explaining the example of a setting of the 2nd high saturation area | region which concerns on this invention, and is a figure which shows the case where a pixel structure is RGBW. It is a chromaticity diagram explaining the example of a setting of the 2nd high saturation area | region which concerns on this invention, and is a figure which shows the case where a pixel structure is RGB. It is a chromaticity diagram explaining the example of a setting of the 3rd high saturation field concerning this invention, and is a figure showing the case where pixel composition is RGBW. It is a chromaticity diagram explaining the setting example of the 3rd high saturation area | region which concerns on this invention, and is a figure which shows the case where a pixel structure is RGB. It is a chromaticity diagram illustrating a setting example of a fourth high saturation region according to the present invention. It is a chromaticity diagram illustrating a setting example of a fifth high saturation region according to the present invention. FIG. 7 is an explanatory diagram of a three-class average coordinate calculation method for explaining a comparative example of whether in a high saturation region or outside according to the present invention. It is a chromaticity diagram illustrating a second luminance control example according to the present invention. It is a chromaticity diagram illustrating a third luminance control example according to the present invention. It is a flowchart explaining the image drive method which concerns on Embodiment 1 of this invention. It is a flowchart explaining the image drive method which concerns on Embodiment 2 of this invention. It is a flowchart explaining the image drive method which concerns on Embodiment 3 of this invention. It is a flowchart explaining the image drive method which concerns on Embodiment 4 of this invention.

SUMMARY OF THE INVENTION Low power consumption and burn-in lifetime depend strongly on luminance, and driving methods such as improvement of materials for organic EL displays and reduction in luminance have been adopted. Until now, the method of reducing the power consumption has mainly been a measure for detecting the luminance or current consumption and reducing the luminance. However, when the current consumption actually increases, the purity (saturation) of the color may be high in addition to the high luminance display of W (white). In particular, when the pixel configuration is RGBW, the power of highly saturated colors (R, G, B, Y, C, M) is larger than that of W display. Further, since the color having high saturation has a large driving current, the characteristic deterioration speed is high and the image tends to be burned in easily. If the color with high saturation is appropriately driven (the drive current is reduced), the deterioration rate can be reduced. Furthermore, in order to enable display of a high-purity color, it is necessary to prepare a power source with higher capability.

  The present invention pays attention to saturation as source data for performing luminance control, and appropriately controls luminance and manages power consumption when displaying a high-purity color. This is particularly effective for a display panel having a pixel configuration of RGBW. The summary of the present invention is summarized as follows.

  Power set from the maximum allowable power Pw at the white point (Setting Power: Ps≈α × Pw, 0 <α ≦ 1), each color indicating the same or larger power (R, G, B, Y, C) , M), and an area with higher color purity is determined as a “high saturation area”. Next, the coordinates of the RGB data are compared with the coordinates of the “high chroma region”, and if at least one of R, G, B, Y, C, and M is in the “high chroma region”, the luminance is lowered. Here, the comparison method between the RGB data and the “high saturation region” includes pixel number comparison in one frame or average coordinate comparison of all pixels.

  Note that the high saturation region is a point r, y, g, c, b showing a value equivalent to the power consumption Ps of a value determined by a multiple of the power consumption Pw at the white point (Ps≈α × Pw, 0 <α ≦ 1). , M. Here, the points r and c are points existing on the line connecting the vertex R and the white point, the points g and m are points existing on the line connecting the vertex G and the white point, and the points b and y are the vertex This is a point existing on the line connecting B and the white point. Then, α = 1 when the pixel configuration is RGBW, and α = 0.5 when the pixel configuration is RGBW.

The control flow for power and characteristic deterioration focusing on the purity of the display color is as follows.
(1) Setting of high saturation area (2) Comparison between inside and outside of high saturation area (3) Decrease in RGB luminance data

(1) Setting of High Saturation Area When the power at the white point (xw, yw) is Pw, an area with higher color purity than the following coordinates is defined as a “high saturation area”.
・ If the pixel configuration is RGBW, obtain the coordinates of each color (R, G, B, Y, C, M) showing the same power as Pw. ・ If the pixel configuration is RGB, use a fraction of Pw (this In the example, find the coordinates of each color (Y, C, M) that is 1/2)

There are the following five methods for setting the high saturation region.
1) Set the area based on the line connecting the vertex of the RGB triangle and the white point on the material-specific chromaticity diagram 2) Circle (RGB) centered on the RGB vertex on the material-specific chromaticity diagram and this vertex Set the intersection area with the circle (YCM) centered on the line connecting the white points. 3) The RGB vertex on the chromaticity diagram specific to the material and the power consumption limit point (YCM) on the line connecting each vertex and the white point 4) Set the intersection area of the circle that passes through the three points and the RGB triangle 4) For example, set the area using each vertex of the standard setting RGB triangle (NTSC area) and white point 5) Simply connect the RGB vertices Set a high saturation region between an edge and a distance away from that edge

(2) Comparison between High Saturation Area and Outside 1) Comparison of the number of pixels in one frame: It is determined whether the point is in the area or outside by a coordinate comparison.
・ Compare pixel by pixel and count the number of pixels present in the area.
It is determined whether or not Expression (1) is satisfied (If Expression (1) is satisfied, luminance is reduced).
Number of pixels in high saturation area / number of pixels in one frame ≧ r (set value) (1)
2) Average coordinate comparison-Find the average coordinates for one frame (accumulate each coordinate and divide by the total number of pixels). There are simple average methods and average methods by region.
-It is determined whether or not it is included in the high saturation region (if included, the luminance is reduced).

(3) Decrease in RGB luminance data As a result of comparing the coordinates of the RGB data with the coordinates of the “high saturation region”, if at least one of R, G, B, Y, C, and M is in the “high saturation region”, the luminance Reduce.

Next, a setting example of the high saturation area will be specifically described.
Setting example of the first high saturation area: setting the area based on the line connecting the vertex of the RGB triangle and the white point on the material specific chromaticity diagram FIG. 1 shows a case where the pixel configuration is RGBW, A high saturation region (gray color) is shown on the degree diagram.
Points R, G, B, Y, C, M, r, g, b, y, c, and m indicate positions on the chromaticity diagram, and Pr, Pg, Pb, Py, Pc, Pm, Pw, Prw, Pgw, Pbw, Pyw, Pcw, and Pmw indicate power consumption at the coordinates.

  Here, the points R, G, B, and W are known values, the point Y is an intersection of a straight line connecting the point B and the point W, and the line segment GR, and similarly, the point C includes the points R and W. The point M is an intersection of the straight line connecting the line segment GB and the point M is the intersection of the line G connecting the point G and the point W and the line segment BR. These points Y, C and M are the material specific points R, G, If B and W are determined, they are uniquely determined. The points r, g, b, y, c, and m are located on the straight lines connecting the point W and the points R, G, B, Y, C, and M, and have the same power as the power consumption Pw at the point W. It is calculated | required as an upper point, and the electric power in each point is an allowable maximum electric power, and can be considered as a power consumption limit point. At this time, Pw = Prw = Pgw = Pbw = Pyw = Pcw = Pmw.

  In FIG. 1, an area that is inside the triangle RGB and outside the polygon (hexagon) rygcbm is set as the high saturation area. That is, a region having a higher purity than the power Pw at the white point W is set as a high saturation region, and the luminance is lowered.

  Further, the example shown in FIG. 2 shows the case of RGB, and the regions of triangles RGy, GBc, and BRm are set as the high saturation region. In the case of RGB, when each of RGB is displayed in a single color, the power consumption does not exceed the power consumption Pw at the white point W. Therefore, when the pixel configuration is RGB, it is necessary to decide whether to adopt the present invention when a fraction of Pw is reached. In FIG. 2, Prw, Pgw, Pbw <1 / 2Pw, and Pw = 1 / 2Pyw = 1 / 2Pcw = 1 / 2Pmw. It can be seen that the high saturation region becomes smaller. It can be said that this high saturation region is set as a region inside the triangle RGB and outside the polygon (hexagon) RyGcBm.

  -Example of setting the second high-saturation area: Setting the intersection area of three circles centered on the RGB vertex on the material-specific chromaticity diagram and the three circles centered on the line connecting this vertex and the white point

  FIG. 3 shows the case of RGBW, and shows a high saturation region on the chromaticity diagram. The radius of the circle centered on each vertex of the triangle RGB is the distance from the points r, g, and b indicating the power consumption equivalent to the power consumption Pw at the white point W. Further, each radius of the circle passing through the points y, c, and m is obtained as follows.

Circle radius Yr = RG distance through point y Circle radius Cr = GB distance through point c Circle radius Mr = BR distance through point m

  In FIG. 3, as the high saturation region, each circle having a radius to the point inside the triangle RGB, centering on each vertex of the triangle RGB, and showing a power consumption equivalent to the power consumption Pw at the white point W And an area that is inside each circle of radius Yr, Cr, and Mr.

  In the example shown in FIG. 4, in the case of RGB, when each of RGB is displayed as a single color, Prw, Pgw, Pbw <1 / 2Pw, and the RGB light emission does not result in power consumption exceeding Pw. FIG. 4 shows a case where Pw = 1 / 2Pyw = 1 / 2Pcw = 1 / 2Pmw, and it can be seen that the high saturation region becomes small. As the high saturation area, an area inside the triangle RGB and inside each circle of the radii Yr, Cr and Mr is set.

  Setting example of the third high saturation region: a circle passing through three points of each vertex of the material specific triangle RGB and a power consumption limit point (y, c, m) on a line connecting each vertex and the white point Set the intersection area with triangle RGB as high saturation area

  FIG. 5 shows the case of RGBW, and shows a high saturation region (gray color) on the chromaticity diagram. The radius of the circle centered on each vertex of the triangle RGB is the distance from the points r, g, and b indicating the power consumption equivalent to the power consumption Pw at the white point W. The outer large circle is a circle that passes through three points (R, y, G), (G, c, B) and (B, m, R). In FIG. 5, as a high saturation region, each circle having an inner radius of the triangle RGB and having a radius to a point having a power consumption equivalent to the power consumption Pw at the white point W, centered on each vertex of the triangle RGB. Three points (R, y, G), (G, c, m) of power consumption limit points (y, c, m) which are inside and on the line connecting each vertex of the triangle RGB and the white point Regions that are inside each of the three circles passing through B) and (B, m, R) are set.

  The example shown in FIG. 6 shows the case of RGB, and each vertex of the material specific triangle RGB and the power consumption limit points (y, c, m) on the line connecting each vertex and the white point This is a case where the intersection region of the circle passing through the three points and the triangle RGB is a high saturation region. In FIG. 6, only circles passing through the three points G, y, and R are shown, and the other two circles are omitted. That is, as the high saturation region, there are three points (R, y, and m) that are inside the triangle RGB, and each of the vertexes of the triangle RGB and the power consumption limit points (y, c, m) on the line connecting each vertex and the white point. G), (G, c, B) and an area inside each of the three circles passing through (B, m, R) are set.

  Setting example of the fourth high saturation area: For example, based on points y, c, and m set using the same or a certain coefficient as the power consumption at each vertex and white point of the standard RGB triangle (NTSC area) You can set the calculated area.

  FIG. 7 shows an example of a high saturation region set based on the standard NTSC chromaticity diagram. A circle was created with a radius passing through a wavelength of R of 580 nm, G of 560 nm, and B of 485 nm, centering on the RGB coordinates. These values are even more suitable if a more appropriate value is selected. Points y, c, and m are points set to be equal to the power consumption at the white point or using a certain coefficient. An arc was created with these points and three points passing through each point of RGB. The coefficient may be determined appropriately from the relationship between actual panel characteristics and power consumption. It is preferable to reduce the luminance in the region overlapping with the actual characteristics of the OLED panel and the high saturation region. That is, as the high saturation region, the inside of the triangle RGB, the center of each vertex of the triangle RGB, and the inside of each circle having a radius passing through an arbitrary wavelength (R is 580 nm, G is 560 nm, and B is 485 nm) In addition, the power consumption at the white point or a point set using a certain coefficient and three points (R, y, G), (G, c, B) and (B, m, R) that pass through each point of RGB ) To set the area inside the arc determined by

  Setting example of the fifth high saturation area: A high saturation area is simply defined between a side connecting the vertices of the triangle RGB and a side away from the side by a certain distance.

FIG. 8 shows an example of a high saturation region in which the side connecting the vertices of the triangle RGB and the side are set in parallel by a certain Y coordinate as described below.
The side R′G ′ is a line segment obtained by moving the Y coordinate of the side RG by −o.
The side G′B ′ is a line segment obtained by moving the Y coordinate of the side GB by −p.
The side B′R ′ is a line segment obtained by moving the Y coordinate of the side BR by + q.
In the example shown in FIG. 8, as the high saturation region, a region obtained by removing the region of the triangle R′G′B ′ from the region of the triangle RGB, that is, inside the triangle RGB and outside the triangle R′G′B ′. A certain area is set as a high saturation area.
The high saturation region can be set by simply determining the values of a, b, and c from the set RGB coordinates, and can be easily set.

Next, a comparative example within or outside the high saturation region will be specifically described.
First Comparative Example The coordinates of the pixels in one frame for each color are compared, and then the number of pixels in the high saturation area with respect to the number of pixels in one frame is compared. That is,
・ Determine whether the point is within the region or outside by comparing the coordinates.
-Accumulate the numbers in the high saturation area.
-The brightness is reduced depending on whether or not Expression (1) is satisfied.
(Number of pixels in the high saturation region) / (number of pixels in one frame) ≧ r (1)
The set value r is a unique value determined by the panel specifications, cost, and the like.

Second Comparative Example 1: Simple Average Coordinate Calculation Method This is to calculate the average coordinate of each color and reduce the luminance when the average coordinate exists in the high saturation region. That is,
Calculate the average coordinates of each color for one frame (accumulate each coordinate and divide by the total number of pixels).
-Brightness is reduced depending on whether it is included in the high saturation area.

The 2: 3 classification average coordinate calculation method In the simple average coordinate calculation method, for example, when each color of RGB constitutes one third of the display image, the average coordinate is the same as the white point, but the power consumption is from Pw. Great value. In view of such a case, a method of classifying and calculating the area for calculating the average coordinates in advance is introduced.

  FIG. 9 shows a diagram in which the area for calculating the average coordinates is classified into three areas. For one frame of video data, as shown in FIG. 9 (a), the area for calculating the average coordinates is R (x, y), G (x, y), three quadrilaterals RYWM, GCWY, and BMWC. B (x, y) is classified into three, and the average coordinates included in the RGB area are calculated. And if it is in an area | region, luminance control will be performed according to the luminance control example mentioned later. Further, as shown in FIG. 9B, the area for calculating the average coordinate is Y (x, y), C (x, y), M (x, y) made up of three triangles RWG, GWB, and BWR. The average coordinates are calculated for all video data. If it is within the region, batch luminance control is performed. From the viewpoint of cost and yield, the region setting and comparison method may be selected in accordance with the development stage, characteristics, inspection, and adjustment throughput.

Next, an example of a decrease in RGB luminance data (luminance control) will be specifically described.
First Luminance Control Example Since the luminance correction needs to maintain the hue of the original video data, it is necessary to reduce the luminance at the same ratio for each RGB. The brightness correction value Y ′ is obtained according to the following equation.
Y ′ = Y × ξ × θ
Here, Y is the initial luminance, ξ is the conversion coefficient, and θ is the high saturation area occupation ratio. The conversion coefficient ξ is a coefficient that gives the maximum value of Y ′ when θ = 1 (when the set value and the occupation ratio are equal to 1 / 2Pyw = 1 / 2Pcw = 1 / 2Pmw). When the brightness is reduced to half, ξ = 0.5. This value depends on the specifications of the display panel and does not change depending on the image data to be displayed as θ. Further, the high saturation area occupation ratio θ is an occupation ratio of pixels existing in the high saturation area with respect to a set value in pixels for one frame, and has the following relationship.
θ = set value / r (occupancy ratio), r = N / total number of pixels ≧ set value In luminance correction, the RGB luminance is determined by adopting θ of the color having the largest occupation ratio θ among the respective RGB.

Second Brightness Control Example The brightness correction value Y ′ is obtained according to the following equation.
Y ′ = Y × ξ
This is a method of reducing the luminance in a lump when included in the designated high saturation region.
When it is reduced to 50% of the initial luminance, ξ = 0.5.

Third Brightness Control Example The brightness correction value Y ′ is obtained according to the following formula.
Y ′ = Y × ξ × η
Here, η represents a saturation rate, and is represented by the following equation.
eta = average coordinate point x _R from the vertex of each color, x _G, r from the distance / colors apex of up to x _B, g, in the example shown in distance diagram 10 to b, the saturation rate of the RGB eta _R, η _G and η _B are expressed as follows.
η _R = Rx _R distance / Rr distance η _G = Rx _G distance / Gg distance η _B = Rx _B distance / Bb distance Saturation rate η adopts the smallest value among RGB, RGB Correct the brightness.

Fourth luminance control example Here, based on RGB video data, average coordinates of Y are calculated from the coordinates of R and G, C is calculated from the coordinates of G and B, and M is calculated from the coordinates of B and R. A correction value Y ′ is obtained.
The brightness correction value Y ′ is obtained according to the following equation.
Y '= Y × ξ × η _YCM
Here, η _YCM represents the saturation rate of YCM.
In the case of the example shown in FIG. 11, the saturation rates η _Y , η _C , and η _M of YCM are expressed as follows.
η _Y = Yx _y distance / Yy distance eta _C = Cx distance saturation constant eta _YCM distance / Mm distance η _M = Mx _m distance / Cc of _c employs the smallest value among the YCM, RGB brightness correction is performed.

  Next, a specific embodiment adopting the above-described setting example of the high saturation area, a comparative example of whether the area is inside or outside the high saturation area, and a reduction (luminance control) example of RGB luminance data will be described in detail.

Embodiment 1 FIG.
FIG. 12 is a flowchart for explaining the image driving method according to the first embodiment of the present invention, which is based on the determination of the high saturation region on the chromaticity diagram shown in FIG. In FIG. 12, the flow to luminance control is composed of the following four steps.
(1) Determination of high saturation area (2) Calculation of pixel coordinates (3) Comparison of pixel data (4) Determination of whether luminance control is necessary

First, the determination of the high saturation area follows the setting example of the first high saturation area described above, and includes the following steps.
On the chromaticity diagram shown in FIG. 1, the coordinates of each RGB point, the power consumption Pw at the white point, and the line segments RG, GB, BR are determined (step S11). The power consumption Pw at the RGB coordinates and the white point is given as a value specific to the material, and the line segments RG, GB, BR are obtained based on this.
The coordinates of each point r, y, g, c, b, m showing power consumption equal to or larger than Pw are obtained (step S12). In the case of the three primary colors RGB, since there is no point equivalent to Pw, it is 1/2 of Pw and is obtained by setting an appropriate value.
Each line segment ry, yg, gc, cb, bm, mr is determined with reference to an equation of a straight line passing through two points (step S13).

  Thereby, a high saturation area is set. The high saturation area on the chromaticity diagram shown in FIG. 1 is set based on a line connecting the vertex of the RGB triangle specific to the material and the white point, and is inside the triangle RGB, and is a polygon (hexagon). An area outside rygcbm is set. That is, a region having a purity higher than the power Pw at the white point W is set as the high saturation region.

  Also, pixel coordinates are calculated. For pixel coordinates, one frame of pixel data is obtained (step S14), and the RGB data is converted into coordinate data of a chromaticity diagram (step S15). Tristimulus values are obtained from RGB data and converted to coordinate data.

  Next, pixel data is compared. It is determined whether or not the pixel coordinates obtained in the pixel coordinate calculation step are present in the high saturation region obtained in the high saturation region determination step. First, it is determined whether or not each pixel exists in the high saturation region (step S16). Comparison between the high saturation region and the outside follows the first comparative example described above. Then, the number N of pixels existing in the high saturation area is counted (step S17).

  Next, it is determined whether or not brightness control is necessary. Whether or not luminance control is necessary is determined based on whether or not the occupation ratio r obtained as the ratio of the number N of pixels in the high saturation region to the number of pixels in one frame is a material-specific setting value, for example, 0.4 or more. (Step S18) If the occupation ratio r is 0.4 or more, which is the set value, it is determined that the brightness control is necessary, and the brightness is corrected to reduce the brightness (Step S19). In this case, the brightness control is controlled according to the first brightness control example described above.

  Therefore, according to the first embodiment, attention can be paid to the saturation of the display color, the luminance can be appropriately reduced for a highly saturated color, and the power consumption and characteristic deterioration of the display can be reduced. .

Embodiment 2. FIG.
FIG. 13 is a flowchart for explaining an image driving method according to the second embodiment of the present invention, which is based on the determination of the high saturation region in the chromaticity diagram shown in FIG. In FIG. 13, the flow up to the luminance control is composed of the following three steps.
(1) Determination of high saturation area (2) Calculation of average coordinates of video data (3) Determination of whether brightness control is necessary

First, the determination of the high saturation area follows the above-described setting example of the second high saturation area, and includes the following steps.
In the chromaticity diagram shown in FIG. 3, the coordinates of the RGB points, the power consumption Pw at the white point, and the line segments RG, GB, BR are determined (step S21). The power consumption Pw at the RGB coordinates and the white point is given as a value specific to the material, and the line segments RG, GB, BR are obtained based on this.

  -Find the coordinates of each point r, y, g, c, b, m showing power consumption equal to or greater than Pw, and find three circles centering on the points R, G, B and passing through r, g, b At the same time, the intersection area between the three circles and the triangle RGB is set as a high saturation area for RGB (step S22). In the case of the three primary colors RGB, since there is no point equivalent to Pw, it is 1/2 of Pw and is obtained by setting an appropriate value.

The center of the circle is on a straight line connecting the white points, and the intersection of the triangle RGB with each vertex of the triangle RGB, three circles of the radii Yr, Cr, and Mr passing through the points y, c, and m A high saturation area related to YCM is set (step S23).
The sum of the high saturation region for RGB and the high saturation region for YCM is set as the high saturation region of the second embodiment.

  Thus, as a high saturation region, inside the triangle RGB, inside each circle having a radius to the point that shows the power consumption equivalent to the power consumption Pw at the white point W, centered on each vertex of the triangle RGB A region that is inside the circles of radius Yr, Cr, and Mr is set.

  Also, average coordinates are calculated. First, pixel data of one frame is obtained (step S24), and RGB data is converted into coordinate data of a chromaticity diagram (step S25). Tristimulus values are obtained from RGB data and converted to coordinate data. Then, the coordinates of all the video data are calculated, and average values (average coordinates) are obtained for the x and y coordinates (step S26).

  Next, it is determined whether or not brightness control is necessary. It is determined whether or not the average coordinate obtained in the average coordinate calculation step is in the high saturation region (step S27). If the average coordinate is in the high saturation region, the luminance is corrected to reduce the luminance (step S28). In this case, the brightness control is controlled according to the second brightness control example described above.

  Therefore, according to the second embodiment, attention can be paid to the saturation of the display color, the luminance can be appropriately reduced for a highly saturated color, and the power consumption and characteristic deterioration of the display can be reduced. .

Embodiment 3 FIG.
FIG. 14 is a flowchart for explaining an image driving method according to the third embodiment of the present invention, which is based on the determination of the high saturation region on the chromaticity diagram shown in FIG. In FIG. 14, the flow up to the luminance control is composed of the following three steps.
(1) Determination of high saturation area (2) Calculation of average coordinates of video data (3) Determination of whether brightness control is necessary

First, the determination of the high saturation area follows the above-described setting example of the third high saturation area, and includes the following steps.
In the chromaticity diagram shown in FIG. 5, the coordinates of the RGB points, the power consumption Pw at the white point, and the line segments RG, GB, BR are determined (step S31). The power consumption Pw at the RGB coordinates and the white point is given as a value specific to the material, and the line segments RG, GB, BR are obtained based on this.

  -Find the coordinates of each point r, y, g, c, b, m showing power consumption equal to or greater than Pw, and find three circles centering on the points R, G, B and passing through r, g, b At the same time, the intersection area between the three circles and the triangle RGB is set as a high saturation area for RGB (step S32). In the case of the three primary colors RGB, since there is no point equivalent to Pw, it is 1/2 of Pw and is obtained by setting an appropriate value.

・ A circle that passes through three points R, y, and G, a circle that passes through three points G, c, and B, and a circle that passes through three points B, m, and R are obtained, and the intersection area between the three circles and the triangle RGB is determined. A high saturation region related to YCM is set (step S33).
The sum of the high saturation region for RGB and the high saturation region for YCM is set as the high saturation region of the third embodiment.

  Thus, as a high saturation region, inside the triangle RGB, inside each circle having a radius to the point that shows the power consumption equivalent to the power consumption Pw at the white point W, centered on each vertex of the triangle RGB There are three points (R, y, G) and (G, c, B) of the power consumption limit points (y, c, m) on the line connecting each vertex of the triangle RGB and the white point. And a region that is inside each of the three circles passing through (B, m, R).

  Also, average coordinates are calculated. First, pixel data of one frame is obtained (step S34), and RGB data is converted into coordinate data of a chromaticity diagram (step S35). Tristimulus values are obtained from RGB data and converted to coordinate data. Then, the area for calculating the average coordinates is classified into R (x, y), G (x, y), and B (x, y), and the average coordinates are calculated for all the video data (step S36). .

  Next, it is determined whether or not brightness control is necessary. It is determined whether or not one or more of the average coordinate bar R (x, y), bar G (x, y), and bar B (x, y) obtained in the average coordinate calculation step are in the high saturation region. (Step S37) If it is in the high saturation region, the trajectory is corrected to reduce the luminance (Step S38). In this case, the brightness control is controlled according to the third brightness control example described above.

  Therefore, according to the third embodiment, paying attention to the saturation of the display color, it is possible to appropriately reduce the luminance for a highly saturated color, and to reduce the power consumption and characteristic deterioration of the display. .

Embodiment 4 FIG.
FIG. 15 is a flowchart for explaining the image driving method according to the fourth embodiment of the present invention, which is based on the determination of the high saturation region on the chromaticity diagram shown in FIG. In FIG. 15, the flow up to the luminance control is composed of the following three steps.
(1) Determination of high saturation area (2) Calculation of average coordinates of video data (3) Determination of whether brightness control is necessary

First, the determination of the high saturation area follows the above-described setting example of the fifth high saturation area, and includes the following steps.
In the chromaticity diagram shown in FIG. 8, the coordinates of the RGB points, the power consumption Pw at the white point, and the line segments RG, GB, BR are determined (step S41). The power consumption Pw at the RGB coordinates and the white point is given as a value specific to the material, and the line segments RG, GB, BR are obtained based on this.

The line segment RG, GB, BR is translated by a certain Y coordinate to obtain a triangle R′G′B ′ (step S42).
That is, the Y coordinate of RG is −o to form R′G ′.
The Y coordinate of GB is −p to form G′B ′.
The Y coordinate of BR is + q to form B′R ′.
Note that 0.0 <o, p, q <1.0.

  A region obtained by excluding the region of the triangle R′G′B ′ from the region of the triangle RGB is set as a high saturation region (step S43).

  As a result, a region obtained by removing the region of the triangle R′G′B ′ from the region of the triangle RGB as the high saturation region, that is, the region inside the triangle RGB and outside the triangle R′G′B ′ is defined as the high saturation region. Set as.

  Also, average coordinates are calculated. First, pixel data of one frame is obtained (step S44), and RGB data is converted into coordinate data of a chromaticity diagram (step S45). Tristimulus values are obtained from RGB data and converted to coordinate data. Then, the area for calculating the average coordinates is classified into three areas Y (x, y), C (x, y), and M (x, y), and the average coordinates are calculated for all the video data (step S46). .

  Next, it is determined whether or not brightness control is necessary. It is determined whether one or more of the average coordinate bar Y (x, y), bar C (x, y), and bar M (x, y) obtained in the average coordinate calculation step are in the high saturation region. (Step S47) If it is in the high saturation area, the brightness is corrected to reduce the brightness (Step S48). In this case, the brightness control is controlled according to the above-described fourth brightness control example.

  Therefore, according to the fourth embodiment, it is possible to set a high saturation area simply by determining the values of o, p, and q from the set RGB coordinates, and pay attention to the saturation of the display color. Therefore, it is possible to appropriately reduce the luminance of a high color, and to reduce power consumption and characteristic deterioration of the display.

The OLED device is a self-luminous type, and power consumption and life (burn-in, half-life) differ depending on the light-emitting material. Since this invention pays attention to the saturation of the display color and suppresses power consumption, the following effects can be achieved.
(1) Since the high saturation color display time is extracted and brightness adjustment is performed, low power consumption and suppression of characteristic deterioration can be realized.
(2) In particular, in the case of RGBW, since the power consumption is higher when displaying the color in the high saturation region than when displaying W, the effects of reducing power consumption and suppressing characteristic deterioration are greater.
(3) Also, in the case of RGBW, since the power at the white point can be set to the peak power, the power management becomes easy and more accurate power control becomes possible.
(4) Since peak power consumption can be suppressed, it is possible to design a power supply with low power consumption and low cost.
(5) By adding the power consumption control based on the display color of the present invention to the conventional luminance control, the power consumption can be accurately managed, and the usage time of the portable device can be prolonged and the energy can be effectively utilized.

In summary, the image driving method according to the present invention can be implemented according to the following aspects.
A setting step for setting a high saturation region with a high saturation of the display color to be displayed on the display, a determination step for determining whether or not display data to be displayed on the display display exists in the set high saturation region, and A luminance control step of controlling to reduce the luminance when the display data exists in the high saturation region.

  In the setting step, an area close to the side of the triangle formed by RGB is set as a high saturation area based on a line connecting a vertex and a white point formed by RGB specific to the material of the display display on the chromaticity diagram.

  As the high saturation region, the power consumption limit points on the same power as the power consumption at the point W, which are located on the straight lines connecting the points R, G, B, Y, C, M and the point W in the chromaticity diagram, respectively. A region having a higher purity than the power at the white point is set, which is obtained inside each triangle formed by RGB and outside the polygon formed by sequentially connecting the power consumption limit points.

  As the high saturation region, the power consumption limit points on the same power as the power consumption at the point W, which are located on the straight lines connecting the points Y, C, M and the point W in the chromaticity diagram, are respectively determined, and RGB is formed. A white point that is inside the triangle and that is outside the polygon formed by interposing the power consumption limit point between the vertices of the triangle and sequentially connecting the power consumption limit point and the vertices of the triangle. An area of higher purity than the power at is set.

  The high saturation region is a point W, which is located on a straight line connecting points R, G, B and W from points R, G, B, with the vertex of a triangle formed by RGB in the chromaticity diagram as the center. The three small circles whose radius is the distance to the power consumption limit points r, g, and b on the same power as the power consumption are calculated, and the center position is on the straight line connecting the points R, G, B, and W. Each of the points Y, C, and M passes through power consumption limit points y, c, m on the same power as the power consumption at the point W, which are located on the straight lines connecting the points Y, C, M and the points W, respectively. , Three great circles whose radius is the distance between the vertices of the triangle formed by RGB adjacent to M, are inside the triangle formed by RGB, are inside the three small circles, and The area inside the great circle is set.

  As the high saturation region, power consumption limit points y, c, m on the same power as the power consumption at the point W, which are located on the straight lines connecting the points Y, C, M and the point W in the chromaticity diagram, respectively. As described above, three circles having a radius between the vertices of the triangle formed by RGB adjacent to the points Y, C, and M are obtained, and are inside the triangle formed by RGB and inside the three circles. An area is set.

  The high saturation region is a point W, which is located on a straight line connecting points R, G, B and W from points R, G, B, with the vertex of a triangle formed by RGB in the chromaticity diagram as the center. 3 small circles having a radius as a distance to the power consumption limit points r, g, and b on the same power as the power consumption of are located on the straight lines connecting the points Y, C, M and the points W, respectively. Three great circles passing through the power consumption limit points y, c, m on the same power as the power consumption at the point W and two adjacent vertices of the triangle formed by RGB with the points y, c, m in between Is set inside the triangle formed by RGB, inside the three small circles, and inside the three great circles.

  As the high saturation region, the power consumption limit points y, c, m on the same power as the power consumption at the point W, which are located on the straight lines connecting the points Y, C, M and the point W in the chromaticity diagram, Three great circles that pass through two adjacent vertices of the triangle formed by RGB with points y, c, and m in between are found inside the triangle formed by RGB and inside the three great circles An area is set.

  As the high-saturation region, three circles having a radius at a distance to a coordinate defined by a predetermined wavelength, each centered on a vertex of a triangle formed by RGB in the chromaticity diagram, and points Y, C, and M are obtained. The three arcs are obtained at three points passing through the power consumption limit points y, c, m and the RGB points on the same power as the power consumption at the point W, which are located on the straight lines connecting the point W and the point W, respectively. A region is set that is inside the triangle formed by, inside the three circles, and inside the three arcs.

  The high saturation region is inside the first triangle formed by RGB in the chromaticity diagram, and is formed within the first triangle, and the side connecting the vertices of the first triangle has a predetermined Y coordinate. A region outside the second triangle formed by translation by the amount is set.

The high saturation region is a point r, y, g, c, b, which indicates a value equivalent to the power consumption Ps of a value determined by a multiple of the power consumption Pw at the white point (Ps≈α × Pw, 0 <α ≦ 1). It is defined based on one of m.
(Here, the points r and c are points on the line connecting the vertex R and the white point,
Points g and m are points existing on the line connecting the vertex G and the white point,
Points b and y are points existing on a line connecting the vertex B and the white point. )

  Α = 1 when the pixel configuration is RGBW, and α = 0.5 when the pixel configuration is RGBW.

  The determination step determines that the pixel exists in the high saturation region when the ratio of the number of pixels in the high saturation region to the number of pixels in one frame is equal to or greater than a predetermined value.

  In the determination step, average coordinates for one frame are obtained, and when the average coordinates are included in the high saturation area, it is determined that the average coordinates exist in the high saturation area.

  The determination step classifies the area for calculating the average coordinates into a plurality of areas in advance, and determines that the high saturation area exists when any one or more average coordinates of the classified areas are included in the high saturation area. .

  The area for calculating the average coordinates is classified into three quadrilateral areas RYWM, GCWY, and BMWC based on the points R, G, B, Y, C, and M on the chromaticity diagram.

  The area for calculating the average coordinates is classified into three triangles RWG, GWB, and BWR based on the points R, G, B, Y, C, and M on the chromaticity diagram.

  In the luminance control step, RGB luminance correction is performed based on the occupation ratio of the color having the highest occupation ratio of the pixels existing in the high saturation region with respect to the set value among the pixels for one frame.

  In the luminance control step, the distance from the vertex of each RGB color to the average coordinate point on the chromaticity diagram and the same power consumption as the power consumption at the point W located on the straight line connecting the vertex and the point W of each RGB color. The luminance correction of RGB is performed based on the smallest saturation ratio given by the ratio to the distance to the power consumption limit points r, g, and b.

  The luminance control step is the same as the power consumption at the point W located on the straight line connecting the set point of each YCM color and the point W, and the distance from the set point of each YCM color to the average coordinate point on the chromaticity diagram. The RGB luminance correction is performed based on the value of the saturation ratio given by the ratio of the distance to the power consumption limit points y, c, and m in terms of power, which is the smallest among the YCMs.

Claims (20)

A setting step for setting a high saturation region with a high saturation of the display color displayed on the display;
A determination step of determining whether or not display data to be displayed on the display is present in the set high saturation region;
A luminance control step of controlling to reduce the luminance when the display data is present in the high saturation region. The image driving method according to claim 1,
In the setting step, an area close to the side of the triangle formed by RGB is set as a high saturation area based on a line connecting a vertex and a white point formed by RGB specific to the display display material on the chromaticity diagram. An image driving method characterized by the above. The image driving method according to claim 2,
As the high saturation region, the power consumption limit points on the same power as the power consumption at the point W, which are located on the straight lines connecting the points R, G, B, Y, C, M and the point W in the chromaticity diagram, respectively. Each of the obtained regions is inside a triangle formed by RGB and is located outside the polygon formed by sequentially connecting the power consumption limit points, and a region having higher purity than the power at the white point is set. Image driving method. The image driving method according to claim 2,
As the high saturation region, the power consumption limit points on the same power as the power consumption at the point W, which are located on the straight lines connecting the points Y, C, M and the point W in the chromaticity diagram, are respectively determined, and RGB is formed. A white point that is inside the triangle and that is outside the polygon formed by interposing the power consumption limit point between the vertices of the triangle and sequentially connecting the power consumption limit point and the vertices of the triangle. An image driving method characterized in that a region having a higher purity than that of electric power is set. The image driving method according to claim 2,
The high saturation region is a point W, which is located on a straight line connecting points R, G, B and W from points R, G, B, with the vertex of a triangle formed by RGB in the chromaticity diagram as the center. The three small circles whose radius is the distance to the power consumption limit points r, g, and b on the same power as the power consumption are calculated, and the center position is on the straight line connecting the points R, G, B, and W. Each of the points Y, C, and M passes through power consumption limit points y, c, m on the same power as the power consumption at the point W, which are located on the straight lines connecting the points Y, C, M and the points W, respectively. , Three great circles whose radius is the distance between the vertices of the triangle formed by RGB adjacent to M, are inside the triangle formed by RGB, are inside the three small circles, and An image driving method characterized in that an area inside a great circle is set. The image driving method according to claim 2,
As the high saturation region, power consumption limit points y, c, m on the same power as the power consumption at the point W, which are located on the straight lines connecting the points Y, C, M and the point W in the chromaticity diagram, respectively. As described above, three circles having a radius between the vertices of the triangle formed by RGB adjacent to the points Y, C, and M are obtained, and are inside the triangle formed by RGB and inside the three circles. An image driving method characterized in that an area is set. The image driving method according to claim 2,
The high saturation region is a point W, which is located on a straight line connecting points R, G, B and W from points R, G, B, with the vertex of a triangle formed by RGB in the chromaticity diagram as the center. 3 small circles having a radius as a distance to the power consumption limit points r, g, and b on the same power as the power consumption of are located on the straight lines connecting the points Y, C, M and the points W, respectively. Three great circles passing through the power consumption limit points y, c, m on the same power as the power consumption at the point W and two adjacent vertices of the triangle formed by RGB with the points y, c, m in between And an area that is inside the triangle formed by RGB, inside the three small circles, and inside the three large circles is set. The image driving method according to claim 2,
As the high saturation region, the power consumption limit points y, c, m on the same power as the power consumption at the point W, which are located on the straight lines connecting the points Y, C, M and the point W in the chromaticity diagram, Three great circles that pass through two adjacent vertices of the triangle formed by RGB with points y, c, and m in between are found inside the triangle formed by RGB and inside the three great circles An image driving method characterized in that an area is set. The image driving method according to claim 2,
As the high-saturation region, three circles having a radius at a distance to a coordinate defined by a predetermined wavelength, each centered on a vertex of a triangle formed by RGB in the chromaticity diagram, and points Y, C, and M are obtained. The three arcs are obtained at three points passing through the power consumption limit points y, c, m and the RGB points on the same power as the power consumption at the point W, which are located on the straight lines connecting the point W and the point W, respectively. An image driving method comprising: setting an area that is inside a triangle formed by, inside the three circles, and inside the three arcs. The image driving method according to claim 2,
The high saturation region is inside the first triangle formed by RGB in the chromaticity diagram, and is formed within the first triangle, and the side connecting the vertices of the first triangle has a predetermined Y coordinate. An image driving method characterized in that an area outside the second triangle formed by parallel translation is set. In the image drive method of any one of Claim 1 to 10,
The high saturation region is a point r, y, g, c, b, which indicates a value equivalent to the power consumption Ps of a value determined by a multiple of the power consumption Pw at the white point (Ps≈α × Pw, 0 <α ≦ 1). m is defined based on any one of the points m (where the points r and c are points on the line connecting the vertex R and the white point,
Points g and m are points existing on the line connecting the vertex G and the white point,
Points b and y are points existing on a line connecting the vertex B and the white point. )
An image driving method characterized by the above. The image driving method according to claim 11,
An image driving method characterized in that α = 1 when the pixel configuration is RGBW and α = 0.5 when the pixel configuration is RGBW. The image driving method according to any one of claims 1 to 12,
The image driving method according to claim 1, wherein the determination step determines that the pixel exists in the high saturation region when a ratio of the number of pixels in the high saturation region to a number of pixels in one frame is equal to or greater than a predetermined value. The image driving method according to any one of claims 1 to 12,
An image driving method characterized in that the determination step calculates average coordinates for one frame and determines that the average coordinates exist in the high saturation area when the average coordinates are included in the high saturation area. The image driving method according to any one of claims 1 to 12,
The determination step classifies the area for calculating the average coordinates into a plurality of areas in advance, and determines that the high saturation area exists when any one or more average coordinates of the classified areas are included in the high saturation area. An image driving method characterized by the above. 16. The image driving method according to claim 15, wherein
Image driving characterized in that the area for calculating the average coordinates is classified into three rectangular areas RYWM, GCWY, and BMWC based on points R, G, B, Y, C, and M on the chromaticity diagram. Method. 16. The image driving method according to claim 15, wherein
Image driving characterized in that the area for calculating the average coordinates is classified into three triangles RWG, GWB, and BWR based on points R, G, B, Y, C, and M on the chromaticity diagram. Method. The image driving method according to any one of claims 1 to 17,
The brightness control step performs RGB brightness correction based on an occupation ratio of a color having the highest occupation ratio of pixels existing in a high saturation area with respect to a set value among pixels for one frame. . The image driving method according to any one of claims 1 to 17,
In the luminance control step, the distance from the vertex of each RGB color to the average coordinate point on the chromaticity diagram and the same power consumption as the power consumption at the point W located on the straight line connecting the vertex and the point W of each RGB color. An image driving method characterized in that RGB luminance correction is performed on the basis of the smallest value of RGB among the saturation ratios given by the ratios to the distances to the power consumption limit points r, g, and b. The image driving method according to any one of claims 1 to 17,
The luminance control step is the same as the power consumption at the point W located on the straight line connecting the set point of each YCM color and the point W, and the distance from the set point of each YCM color to the average coordinate point on the chromaticity diagram. An image driving method characterized in that RGB luminance correction is performed based on a value of a saturation ratio given by a ratio to distances to power consumption limit points y, c, and m on the basis of power, which is the smallest among YCMs.

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