JP2003029696A - Method and system for correcting luminance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate line-shaped luminance non-uniformity by calculating a line luminance correction value from image information through a simple method concerning the line-shaped luminance non-uniformity on a display device. SOLUTION: An image on an image display device 1 having a plurality of display elements arranged in the shape of matrix is read by a CCD camera 2, horizontal or vertical line luminance is calculated, a correction value is calculated from the line luminance for each line and on the basis of the correction value, the line luminance is corrected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for correcting horizontal or vertical line-shaped luminance unevenness of a display device.

[0002]

2. Description of the Related Art FIG. 12 schematically shows a panel structure of a surface conduction electron-emitting device (hereinafter referred to as "SED"). 1000 is a face plate (hereinafter F
P), 1001 is a rear plate (hereinafter RP), 1002
Is a spacer and 1003 is an emitting element. In the actual panel, the FP 1000 and the RP 1001 are sealed via the spacer 1002, and the inside is evacuated.

The spacer 1002 is provided to support atmospheric pressure from inside the panel, which is a vacuum container.
In this conventional example, it is assumed that the spacers are arranged in the horizontal direction. The emitting elements 1003 are connected in a matrix on the RP 1001 by row and column direction wiring (not shown). Then, electrons are emitted in a vacuum, and the phosphor (not shown) coated on the FP 1000 is irradiated with electrons by the acceleration voltage applied between the FP and RP to display an image.

In the SED, horizontal line-shaped luminance unevenness may occur when an image is displayed. One of the causes is that the spacer 1002 is charged and the electric field is disturbed in the vicinity of the spacer 1002.

FIG. 13 is a diagram for explaining the occurrence of line-shaped luminance unevenness on the first proximity line of the spacer 1002. The figure is a sectional view of the panel. 1000 is F as in FIG.
P, 1001 is RP, 1002 is a spacer, and 1003 is an emitting element.

If the electric field is not disturbed in the vicinity of the spacer 1002, the electrons emitted from the emitting element 1003 will have an electron orbit 1.
Like 010, it is parallel to the spacer. However, when the spacer 1002 is positively (+) charged at the time of displaying an image, the electrons are bent in the direction in which the spacer 1002 is attracted like the electron trajectory 1011. That is, the electron beams, which are supposed to be arranged at equal intervals on all lines, are brought close to each other only in the vicinity of the spacer. As a result, bright line-shaped luminance unevenness occurs near the spacer.

Not only the brightness unevenness due to such beam position shift, but also the line-shaped brightness unevenness may occur due to the brightness of one line being different from that of another line in the SED.

[0008]

In the past, this line-shaped luminance unevenness deteriorated the image quality. An object of the present invention is to eliminate the line-shaped luminance unevenness by calculating the line luminance of each display device by some method and correcting the luminance from the line luminance value.

[0009]

In the brightness correction method of the present invention, for a plurality of display elements arranged in a matrix, which are respectively connected to a plurality of row wirings and column wirings, The row wiring is sequentially scanned by the scanning means,
A method of correcting the line luminance of an image display device, which performs modulation on the column wiring by a modulator to cause the display element to emit light and display an image, wherein the line luminance in the row wiring direction or the column wiring direction is The method is characterized by including a step of calculating, a step of calculating a correction value for each line from the calculated line luminance, and a step of correcting the line luminance based on the correction value.

The step of calculating the line luminance is characterized in that the image displayed on the image display device is photographed, the photographed image is converted into luminance data, and the line luminance is calculated from the luminance data. To do.

In the step of calculating the line brightness, the line brightness is calculated based on the first profile data obtained by averaging the brightness data in the row wiring direction or the column wiring direction.

The step of calculating the line brightness is characterized in that the line brightness is calculated based on the second profile data obtained by processing the first profile data and a predetermined correction value.

In the step of calculating the line brightness, a peak position in the first profile data or the second profile data is calculated, and the line position is calculated in a range of one pixel corresponding to the display element centering on the peak position. It is characterized in that the line luminance is calculated by a value obtained by averaging the first profile data or the second profile data.

In the step of calculating the line brightness, a peak position in the first profile data or the second profile data is calculated, and a value of the first profile data or the second profile data at the peak position is calculated. The line brightness is calculated by

In the step of calculating the line luminance, the peak position in the first profile data or the second profile data is calculated, and (i-1)
In the range from the center between the i-th peak and the i-th peak to the center between the i-th peak and the (i + 1) -th peak, the first profile data or the second profile data
It is characterized in that the i-th line luminance is calculated by averaging the profile data of.

In the step of calculating the line luminance, a peak position in the first profile data or the second profile data is calculated, and (i-1)
The distance between the i-th peak and the i-th peak and the distance between the i-th peak and the (i + 1) -th peak are compared, and the smaller distance is defined as di, and within the range from the i-th peak to ± di, It is characterized in that the i-th line luminance is calculated by a value obtained by averaging the first profile data or the second profile data.

In the step of calculating the line luminance, the peak position in the first profile data or the second profile data is calculated, and (i-1)
In the range from the center between the i-th peak and the i-th peak to the center between the i-th peak and the (i + 1) -th peak, the first profile data or the second profile data
The i-th first line luminance is calculated by averaging the profile data of, and the distance between the (i-1) th peak and the i-th peak and the distance between the i-th peak and the (i + 1) th peak are calculated. The distance of the smaller one is set to di, and sqr
It is characterized in that the i-th line luminance is calculated from the correction coefficient of t (1 / di) and the i-th first line luminance.

The correction value is a value proportional to the reciprocal of the line luminance.

The correction value is a correction value standardized as 0 <correction value ≦ 1.

The step of correcting the line luminance on the basis of the correction value includes the step of displaying the same image signal before and after the correction.
The correction is performed so that the corrected line brightness becomes a value obtained by multiplying the uncorrected line brightness by the standardized correction value.

Further, in the brightness correction system of the present invention, means for reading the image information of the image display device and line brightness in the row wiring direction or the column wiring direction are calculated based on the image information. Line brightness calculation means, line brightness correction value calculation means for calculating a line brightness correction value for each line from the line brightness, and line brightness correction means for correcting the line brightness based on the line brightness correction value,
It is characterized by having.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be illustratively described in detail below with reference to the drawings. However, the dimensions of the components described in this embodiment,
Unless otherwise specified, the material, the shape, the relative arrangement, and the like are not intended to limit the scope of the present invention thereto.

(First Embodiment) As a first embodiment of the present invention, a method of averaging profile data within a range of one pixel corresponding to a display element to obtain a line luminance will be described.

First, the step of calculating the line luminance in the row wiring direction or the column wiring direction will be described.

FIG. 1 is a diagram of measurement for obtaining luminance data of each line of SED. In FIG. 1A, 1 is an SED panel and 2 is a CCD camera. C as shown
Each line of the SED panel 1 is enlarged and photographed by the CD camera 2. To improve the accuracy of the correction, at least SED
About 100 pixels of CCD are required for one pixel. Further, at this time, the horizontal direction of the SED and the horizontal direction of the CCD camera need to match. If these do not match, there arises a problem that the profile calculation described later cannot be performed accurately.

FIG. 1B shows the luminance data converted from the data photographed by the CCD camera 2. 3 is SE
One pixel of D, line 9 and line 10 are a part of one horizontal line of the SED panel (range photographed by CCD).
There is a spacer between line 9 and line 10. Therefore, the average luminance of the lines 9 and 10 is different from that of the other lines, and horizontal line-shaped luminance unevenness occurs.

First, the brightness data taken by the CCD camera 2 is averaged in the horizontal direction as shown in FIG. 2 to obtain the first profile data 100 (one-dimensional data). First
One mountain of the profile data 100 of 1 corresponds to one SED pixel. In the present embodiment, since the line-shaped luminance unevenness in the horizontal direction, the profile data is obtained by averaging in the horizontal direction. If there is a vertical luminance unevenness, profile data is obtained by averaging in the vertical direction. The line brightness is calculated based on this profile data.

In FIG. 2, line 9 as in FIG.
Line 10 is the first proximity line of the spacer. In this embodiment, the spacer first proximity line is brighter than the other lines. Therefore, the line brightness corresponding to the lines 9 and 10 of the first profile data 100 has a high value.

The obtained first profile data 10
Calculate the line brightness from 0. In this embodiment, SE
The average of the first profile data 100 in the range of D1 pixels is taken as the line luminance. FIG. 3 is a diagram for explaining the line luminance calculation method in the present embodiment.

In FIG. 3, the first profile data 100 is displayed rotated by 90 degrees. The dotted line in the figure is S
The range for one ED pixel is shown. This range 1 to range 1
All 7 are equal. There are a plurality of ways of obtaining the range 1 to range 17, and there is a method of obtaining as follows, for example.

First, the peak position of each line is detected from the first profile data 100. The black circles in FIG. 3 indicate the peak positions of each line. Next, using the example of FIG. 3, the distance D1 between the peak of line 1 and the peak of line 17 is obtained.

A value D obtained by dividing the distance D1 by 16 (= 17-1) is the width of one SED pixel. Ranges 1 to 17 are centered on the peaks of lines 1 to 17 and have a width D.
If there is no beam position deviation as shown in FIG.
7 do not overlap each other.

Lines 1 to 17 represent each horizontal line of the SED. In the present embodiment, the brightness of the line i is a value obtained by averaging the first profile data 100 in the range i. FIG. 4 shows a numerical value of the line luminance calculated from the profile data of FIG. 3 and a graph thereof.

Next, the step of calculating the brightness correction value from the line brightness will be described with reference to FIG. First, the reciprocal of each line brightness is obtained. This is shown in FIG.
It is a conversion from the table of (1) to the table of (b). Next, the reciprocal of the brightness (FIG. 5B) is standardized to 0 to 1 and used as the brightness correction value. This is a conversion from the table of FIG. 5B to the table of FIG. As a result, for example, the correction value of the lowest brightness line becomes 1 (that is, the brightness is not changed even after correction), and the correction value of the line having twice the brightness of the lowest brightness line is 0.5.
(That is, after the correction, the luminance becomes 1/2 of that before the correction). In the example of FIG. 5, the correction value is 1 because line 4 is the darkest.
(The brightness is not changed even after the correction), the line 9 is brightest and the correction value is 0.748 (the corrected brightness is 0.748 before the correction).
Times).

Next, the step of correcting the brightness of each line according to the calculated correction value will be described. For example, if the correction value is 1, the brightness of that line is not changed. Alternatively, if the correction value is 0.5, the line will have a brightness of 1 /
Correction such as dropping to 2. That is, the corrected line brightness is corrected to be a value obtained by multiplying the corrected line brightness by the correction value. A plurality of correction means are conceivable, but any method can be used as long as it is possible to multiply an image signal by a correction value.

FIG. 6 shows the profile data obtained after the correction. Thus, the brightness profile is almost uniform.

This method is particularly effective for correction when the beam position deviation is small.

(Second Embodiment) As a second embodiment of the present invention, a method of setting the peak value of each line as the line luminance will be described.

In the present embodiment, the steps from the luminance data measurement to the calculation of the first profile data 100 (FIG. 2) are exactly the same as those in the first embodiment. here,
The line luminance calculation method after the first profile data 100 is obtained will be described.

In the present embodiment, each line peak value of the obtained profile data is directly used as each line luminance. The position marked with a black circle (•) in FIG. 7 is the line peak position. The brightness value at this point is the line brightness.
For example, the line brightness of the line 9 is L9.

The method of calculating the brightness correction value from the obtained line brightness is exactly the same as in the first embodiment (FIG. 5).

This method is effective when the beam position deviation is small and the beam shape is uniform.

(Third Embodiment) As a third embodiment of the present invention, a method of setting line luminance as an average value between peaks and centers of peaks will be described. This correction value calculation method is a method which is experimentally derived by actually correcting the SED.

In this embodiment, the steps from the measurement of the brightness data to the calculation of the first profile data 100 (FIG. 2) are the same as those in the first embodiment. Consider an example in which the obtained first profile data 100 is as shown in FIG. Also in this embodiment, the spacer is line 9,
It is between lines 10. And line 9 and line 10
At the same time as the beam position is shifted, the brightness also varies.

When the first profile data 100 of FIG. 8 is obtained, a predetermined filter is applied to the first profile data 100 to obtain a luminance waveform recognized by a person. In order to improve the calculation accuracy, it is desirable that this filter has a human eye frequency characteristic. Figure 9
A filter derived from Barten's formula in (a) is shown (reference: Barten “The SQRI Method: A New Method
for the Evaluation of Visible Resolution on a Disp
lay. ”, Proceedings of the SID, 28, 253-262, 1987
). Second profile data 10 shown in FIG. 9B
No. 1 is obtained by applying the filter of FIG. 9A to the first profile data 100 of FIG. In calculation, the filter of FIG. 9A may be convolved with the profile data 100. That is, this second profile data 101 is a luminance waveform recognized by humans.

FIG. 10 shows the second profile data 101.
3 is an enlarged view of the vicinity of lines 9 and 10. The line luminance calculation method according to the present embodiment will be described with reference to this figure.

First, the peak position of each line is obtained. The peak position is indicated by a black circle in the figure. Next, the center of two consecutive peaks is calculated. The dotted line in the figure is the center of two consecutive peaks. For example, dotted line 20 is the center of lines 8 and 9. The second profile data 101 is averaged in the range surrounded by the dotted line to obtain the line luminance.

For example, the line brightness of the line 9 is a value obtained by averaging the second profile data 101 in the range 9.

As a result, the average range of lines that are attracted to each other, such as line 9 and line 10, is narrowed,
The line brightness has a high value. That is, when two lines are close to each other, the line brightness is calculated to be high.

The method of obtaining the brightness correction value from the line brightness is exactly the same as in the first embodiment.

In this embodiment, the line luminance is corrected in consideration of the beam position deviation. Therefore, even if the beam position is deviated, it can be dealt with.

By this correction, the linear luminance unevenness is satisfactorily corrected even in the panel where the beam position is deviated.

(Fourth Embodiment) As a fourth embodiment of the present invention, a method of setting the line luminance as an average value in a range in which the shorter one of the peak-to-peak centers is doubled will be described. This correction value calculation method is a method which is experimentally derived by actually correcting the SED.

In this embodiment, from the measurement of the luminance data to the determination of the second profile data 101 (FIG. 10),
This is exactly the same as in the third embodiment.

The line luminance calculation method of this embodiment will be described with reference to FIGS. 11 (a) and 11 (b).

First, the peak position of each line is obtained. The peak position is indicated by a black circle in FIG.
Next, the center of two consecutive peaks is calculated. For example,
20 is the center of line 8 and line 9.

Next, the distance from the peak position to the center between the peaks is calculated. For example, focusing on the line 9 in FIG. 11A, two distances A and B are obtained. Then, the smaller one of A and B (B) is doubled (2
B) is the averaging range.

That is, as shown in FIG. 11B, the second position is within the range of ± B (range 9) centering on the peak position of the line 9.
Line 9 is the average of profile data 101 of
And the brightness of.

As a result, the average range of lines that are attracted to each other, such as line 9 and line 10, is narrowed,
The line brightness has a high value. That is, when two lines are close to each other, the line brightness is calculated to be high.

The method of obtaining the brightness correction value from the line brightness is exactly the same as in the first embodiment.

In this embodiment, the line luminance is corrected in consideration of the beam position deviation. Therefore, even if the beam position is deviated, it can be dealt with.

By this correction, the linear luminance unevenness is satisfactorily corrected even in the panel where the beam position is deviated. This is particularly effective when it is desired to suppress the bright line that occurs when two lines are close to each other.

(Fifth Embodiment) As a fifth embodiment of the present invention, a method of setting the line luminance to a value obtained by multiplying an average value between peaks and a center of the peak by a predetermined coefficient will be described. This correction value calculation method is a method which is experimentally derived by actually correcting the SED.

In the present embodiment, from the luminance data measurement to the determination of the second profile data 101 (FIG. 10),
This is exactly the same as in the third embodiment.

First, the line luminance calculation method of this embodiment will be described with reference to FIG.

First, the peak position of each line is obtained. The peak position is indicated by a black circle in the figure. Next, the center of two consecutive peaks is calculated. The dotted line in the figure is the center of the two peaks. For example, 20 is the center of lines 8 and 9. The second profile data 101 is averaged in the range surrounded by the dotted line to obtain the first line luminance. For example, the first line brightness of the line 9 is the second line in the range 9
The profile data 101 is averaged. That is, the first line luminance is the same as the line luminance calculated by the method of the third embodiment.

Next, the line luminance calculation method will be described with reference to FIG.

First, the distance from the peak position to the center between the peaks is obtained. For example, focusing on the line 9 in FIG. 11A, two distances A and B are obtained. The square root (sq) of the reciprocal of the smaller of A and B (B)
Let rt (1 / B)) be the coefficient. The line luminance is the first line luminance multiplied by this coefficient (sqrt (1 / B)). That is, the line brightness of the line i is expressed by the following equation.

Line luminance i = first line luminance i × sqrt
(1 / MIN (Ai, Bi)) where MIN is a function that returns the smaller value in (). In addition, Ai and Bi are A and B of the i-th line (see FIG. 11A, the fourth embodiment).

The method of obtaining the brightness correction value from the line brightness is exactly the same as in the first embodiment.

In this embodiment, the line luminance is corrected in consideration of the beam position deviation. Therefore, even if the beam position is deviated, it can be dealt with.

By this correction, the linear luminance unevenness is satisfactorily corrected even in the panel where the beam position is deviated.

[0073]

As described above, according to the brightness correction method of the present invention, it is possible to correct the line-shaped brightness unevenness of the display device by a simple calculation.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing elements for measuring an SED panel with a CCD camera.

FIG. 2 is a schematic diagram showing first profile data.

FIG. 3 is a diagram showing a line luminance calculation method in the first embodiment.

FIG. 4 is a diagram showing calculated line luminance in the first embodiment.

FIG. 5 is a diagram illustrating a method of obtaining a brightness correction value from line brightness according to the first embodiment.

FIG. 6 is profile data corrected by the brightness correction method according to the first embodiment.

FIG. 7 is a diagram showing a line luminance correction value calculation method according to the second embodiment.

FIG. 8 is profile data before luminance correction according to the third embodiment.

FIG. 9 is a diagram showing a filter having frequency characteristics of human eyes.

FIG. 10 is a diagram showing a line luminance correction value calculation method according to the third embodiment.

FIG. 11 is a diagram showing a line luminance correction value calculation method according to the third embodiment.

FIG. 12 is a schematic diagram showing a configuration of an SED panel.

FIG. 13 is a diagram showing occurrence of line-shaped luminance unevenness on the first proximity line of the spacer.

[Simple explanation of symbols]

1 SED panel 2 CCD camera 100 First Brofile data 101 Second profile data 1000 face plate 1001 rear plate 1002 spacer 1003 Emissive element 1010 electron orbit 1011 D value of electron orbit

Continued front page    (72) Inventor Yukio Hiraki             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Kohei Inamura             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Masaru Tada             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation F-term (reference) 5C021 PA01 PA56 PA58 PA66 PA76                       RB03 XA66                 5C080 AA18 BB05 DD05 JJ01 JJ04                       JJ05 JJ06

Claims (13)

[Claims] 1. A scanning unit sequentially scans the row wirings for a plurality of display elements arranged in a matrix and connected to a plurality of row wirings and column wirings, respectively, and the modulation unit Modulate the column wiring,
A method of correcting the line luminance of an image display device for causing the display element to emit light to display an image, the step of calculating the line luminance in the row wiring direction or the column wiring direction, and each of the calculated line luminances. Calculating a correction value for each line, and correcting the line brightness based on the correction value,
A brightness correction method comprising: 2. The step of calculating the line luminance includes photographing an image displayed on the image display device, converting the photographed image into luminance data, and calculating the line luminance from the luminance data. The brightness correction method according to claim 1, wherein the brightness correction method is used. 3. The line luminance is calculated in the step of calculating the line luminance by the first profile data obtained by averaging the luminance data in the row wiring direction or the column wiring direction. 2. The brightness correction method described in 2. 4. The step of calculating the line brightness is characterized in that the line brightness is calculated from second profile data obtained by arithmetically processing the first profile data and a predetermined correction value. The brightness correction method according to claim 3. 5. The step of calculating the line brightness calculates a peak position in the first profile data or the second profile data, and a range for one pixel corresponding to the display element is centered on the peak position. 5. The brightness correction method according to claim 3, wherein the line brightness is calculated based on a value obtained by averaging the first profile data or the second profile data. 6. The step of calculating the line luminance calculates a peak position in the first profile data or the second profile data, and calculates the peak position in the peak position, or the first profile data or the second profile data. The brightness correction method according to claim 3 or 4, wherein the line brightness is calculated based on the value of. 7. The step of calculating the line luminance calculates a peak position in the first profile data or the second profile data,
1) The first profile data or the second profile data is averaged in the range from the center of the i-th peak to the center of the i-th peak and the (i + 1) -th peak. The brightness correction method according to claim 3, wherein the i-th line brightness is calculated based on the value. 8. The step of calculating the line luminance calculates a peak position in the first profile data or the second profile data, and calculates (i-
1) The distance between the i-th peak and the i-th peak and the distance between the i-th peak and the (i + 1) -th peak are compared, and the smaller distance is defined as di, and the range from the i-th peak to ± di , I by the averaged value of the first profile data or the second profile data
The third line luminance is calculated, and the third line luminance is calculated.
Alternatively, the brightness correction method according to item 4. 9. The step of calculating the line luminance calculates a peak position in the first profile data or the second profile data, and calculates (i-
1) The first profile data or the second profile data is averaged in the range from the center of the i-th peak to the center of the i-th peak and the (i + 1) -th peak. The i-th first line luminance is calculated according to the value, and the distance between the (i-1) -th peak and the i-th peak and the i-th peak and (i +
1) The distance to the 1st is compared, the smaller distance is set to di, and the i-th line luminance is calculated by the correction coefficient of sqrt (1 / di) and the i-th first line luminance. The brightness correction method according to claim 3 or 4. 10. The brightness correction method according to claim 1, wherein the correction value is a value proportional to an inverse of the line brightness. 11. The correction value is a correction value standardized to 0 <correction value ≦ 1.
The brightness correction method according to any one of items 1. 12. The step of correcting the line brightness based on the correction value includes: when the same image signal is displayed before and after the correction, the corrected line brightness is the normalized correction value to the line brightness before the correction. 12. The brightness correction method according to claim 1, wherein the correction is performed so as to obtain a value obtained by multiplying by. 13. A means for reading image information of the image display device, a line luminance calculating means for calculating line luminance in the row wiring direction or the column wiring direction based on the image information, and from the line luminance. A brightness correction system comprising: a line brightness correction value calculation means for calculating a line brightness correction value for each line; and a line brightness correction means for correcting a line brightness based on the line brightness correction value. .