JP2004177292A - Irregularity inspection method of periodic luminescence pattern - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inspect easily and surely luminescence irregularities of a periodic luminescence pattern in the luminescent state of phosphors arrayed and formed periodically. <P>SOLUTION: When inspecting the luminescence irregularities generated in the periodic luminescence pattern when the phosphors are allowed to luminesce relative to an inspection object wherein the phosphors emitting each colored light of RGB respectively are arrayed and formed periodically, the periodic luminescence pattern is imaged, and an inspection image is inputted. Then, the maximum brightness value is extracted in each high brightness region from a brightness distribution in the perpendicular direction to the longitudinal direction of the high brightness region relative to the inputted inspection image, and a maximum value image is formed by arraying each extracted maximum brightness value by using a pixel as a unit, to thereby inspect the luminescence irregularities of the periodic luminescence pattern based on the formed maximum value image. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
INDUSTRIAL APPLICABILITY The present invention is applied to a method for inspecting unevenness of a periodic light-emitting pattern, and particularly to inspecting light-emitting unevenness occurring in a periodic light-emitting pattern when a phosphor arranged periodically on a plasma display panel emits light. The present invention relates to a method for inspecting unevenness of a periodic light-emitting pattern.
[0002]
[Prior art]
FIG. 3A is a schematic plan view showing an image of a back plate 10 of a so-called plasma display panel (hereinafter, also referred to as PDP), and FIG. FIG. As can be seen from the cross-sectional shape of the PDP back plate 10, a plurality of ribs 12 constituting parallel partitions extending in one direction are formed, and R (red), G ( The phosphors 14 that emit light of each color of green (green) and blue (blue) are repeatedly arranged, and are formed so that each color emits light periodically.
[0003]
In the PDP, since the coloring accuracy depends on the quality of the adhesion of the phosphors that emit RGB light, it is important to inspect the light emission unevenness of the phosphors. The light emission unevenness occurring in the periodic light emission pattern when such a phosphor is caused to emit light is, for example, not shown, by using three monochrome licensing cameras and a linear UV light source for emitting the phosphor. In the state of use, the light source irradiates the PDP which is the inspection object with the UV light to emit the fluorescent material, and these cameras take images for each of RGB to acquire (input) three inspection images. Next, a high-luminance area constituting the periodic light-emitting pattern is extracted from these inspection images, and a non-uniformity visualized image for each RGB is created. Thereafter, the non-uniformity visualized image is displayed on a monitor and visually inspected, or It is conceivable that the inspection is automatically performed by using a non-uniformity inspection process as disclosed in JP-A-2001-28059.
[0004]
[Problems to be solved by the invention]
By the way, when a high-luminance area corresponding to a periodic light-emitting pattern is extracted from the above-described inspection image to create a non-uniformity visualization image, FIG. As shown, each high-luminance area in the inspection image is scanned so as to cross from the top for each pixel row along the broken line, and the pixels whose luminance values are equal to or larger than the threshold value are narrowed in accordance with the arrangement order, whereby the phosphor It is conceivable to remove a gap between the high luminance regions corresponding to the arrangement interval. Note that the threshold used at this time only needs to be able to separate the high-luminance area and the background portion, and an appropriate value can be obtained in advance by an experiment.
[0005]
However, as shown in FIG. 5, one luminance profile (luminance distribution) obtained by scanning the inspection image as described above has a luminance distribution in a high luminance region having a mountain shape as shown in FIG. Therefore, when pixels whose luminance values are equal to or greater than the threshold value (= 180) are extracted, the result is as shown in FIG. 6. When the luminance values of these pixels are rearranged in a state where the intervals are reduced in units of pixels, the luminance becomes As shown in the enlarged view of FIG. 7, the luminance distribution varies regardless of the presence or absence of unevenness. Therefore, in such a method of extracting a high-luminance area, visualization is possible if the contrast is strong, but the unevenness having a weak contrast is difficult to visualize because the base is not flat as shown in FIG. There's a problem.
[0006]
SUMMARY OF THE INVENTION The present invention has been made to solve this problem, and it is possible to easily and surely inspect the light emission unevenness occurring in a periodic light emission pattern obtained when light is emitted from periodically arranged phosphors. An object of the present invention is to provide a method for inspecting unevenness of a periodic light emitting pattern that can be performed.
[0007]
[Means for Solving the Problems]
The present invention relates to a cycle for inspecting light emission unevenness occurring in a periodic light emission pattern when a fluorescent substance emits light, for an inspection object in which fluorescent substances emitting respective colors of RGB are periodically arranged. A method for inspecting unevenness of a non-uniform light-emitting pattern, wherein an image of the periodic light-emitting pattern is taken and an inspection image is input, and in the input inspection image, a luminance distribution in a direction orthogonal to a longitudinal direction of a high-luminance region is obtained. A maximum brightness value is extracted for each brightness region, a maximum value image is created by arranging the extracted maximum brightness values in units of pixels, and light emission unevenness of the periodic light emission pattern is based on the created maximum value image. The above problem has been solved by inspecting.
[0008]
That is, in the present invention, the maximum value of the luminance value in the high luminance area on the inspection image corresponding to the state in which the phosphor emits light is extracted, and only the maximum luminance value is regularly arranged to create the maximum value image. As a result, it is possible to accurately reflect variations in luminance, and it is possible to easily and reliably detect unevenness of the periodic light emitting pattern from the created maximum value image.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0010]
In the present embodiment, the PDP back plate (inspection object) as shown in FIG. 3 in which the phosphors respectively emitting the respective colors of RGB are arranged at a predetermined period, and the phosphors are caused to emit light. The light emission unevenness occurring in the periodic light emission pattern at the time of the inspection is inspected as follows.
[0011]
First, the PDP back plate is irradiated with UV light from a UV light source (not shown) to cause the phosphor to emit light, and the periodic light emission pattern obtained under the light emission state is converted into RGB light by a camera (not shown). Each time, an inspection image corresponding to FIG. 4 is input.
[0012]
Next, from the luminance distribution (profile) of the input inspection image in the direction orthogonal to the longitudinal direction of the high-luminance area in units of pixels corresponding to FIG. 5, as shown in FIG. The maximum luminance value existing for each high luminance area is extracted. The extraction of the maximum luminance is executed for all the pixel rows arranged in the longitudinal direction.
[0013]
Each of the maximum luminance values extracted for each pixel column in this manner is separated by a space between high luminance regions given by horizontal coordinate values in pixel units, and therefore, except for pixels having a luminance value of 0, By rearranging the pixel positions in the left direction in the drawing and rearranging them, a maximum value image having a luminance profile as shown in an enlarged manner in FIG. The light emission unevenness of the periodic light emission pattern is inspected based on the image.
[0014]
The actual unevenness inspection can be performed by visually displaying the maximum value image created as described above on a screen or by using a spatial filter (not shown) disclosed in the above-mentioned publication. May be automatically performed by applying the above method.
[0015]
According to the present embodiment described above, as a process of extracting a high-luminance region corresponding to a periodic light-emitting pattern from an inspection image, a maximum-value image in which the maximum luminance value of the high-luminance region is selected as a representative value is created. Accordingly, an image having a flat base can be obtained, and visualization is easy even for unevenness with low contrast, so that the unevenness can be reliably detected.
[0016]
As described above, the present invention has been specifically described. However, the present invention is not limited to the above-described embodiment, and can be variously modified without departing from the gist thereof.
[0017]
For example, the arrangement of the maximum luminance values is not limited to the case where one pixel is a unit, but may be a case where a plurality of pixels are a unit.
[0018]
Further, the extraction of the maximum luminance value does not necessarily need to be performed for all pixel columns, and may be performed at intervals of one pixel column or more. In this case, the inspection (image processing) time can be reduced.
[0019]
【The invention's effect】
As described above, according to the present invention, it is possible to easily and surely inspect the light emission unevenness occurring in the periodic light emission pattern which is the light emission state of the phosphors periodically arranged and formed.
[Brief description of the drawings]
FIG. 1 is a diagram showing a profile obtained by extracting a maximum luminance value for each high-luminance region from an inspection image. FIG. 2 is a diagram showing a luminance profile of a maximum-value image created using the above-mentioned maximum luminance value. FIG. 4 is a plan view and a cross-sectional view showing an image of a back plate of a plasma display panel. FIG. 4 is an explanatory view showing an image of an inspection image obtained by capturing a periodic light emitting pattern. FIG. FIG. 6 is a diagram showing a profile of a luminance value equal to or higher than a threshold value extracted from the luminance profile. FIG. 7 is a diagram showing a profile in which luminance values equal to or higher than the threshold value are rearranged in pixel units. Explanation of code]
10 PDP back plate 12 Rib 14 Phosphor

Claims (2)

For a test object in which phosphors that respectively emit RGB colors are periodically arranged, a periodic light emission pattern for inspecting light emission unevenness occurring in the periodic light emission pattern when the phosphors emit light is used. An unevenness inspection method,
Imaging the periodic light emitting pattern and inputting an inspection image,
In the input inspection image, from the luminance distribution in the direction orthogonal to the longitudinal direction of the high luminance area, extract the maximum luminance value for each high luminance area,
A maximum value image is created by arranging the extracted maximum brightness values in units of pixels,
A non-uniformity inspection method for a periodic light-emitting pattern, wherein the non-uniform light-emission of the periodic light-emitting pattern is inspected based on the created maximum value image. 2. The method according to claim 1, wherein the extraction of the maximum luminance value is performed for all pixel columns.

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