JP2008180602A - Inspection apparatus, testing method, inspection program, and computer readable medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To equalize an imaging condition in the whole region of a display device by setting imaging magnification suppressing the occurrence of moire. <P>SOLUTION: An inspection apparatus 1 includes: an imaging device 3 for imaging the display device 6 at a plurality of times while modifying an imaging distance; a resolution evaluation calculation part 16 for calculating an evaluation value indicating unevenness of extracted pixel values at each picked up image by extracting the pixel values output from an imaging element included in first and second attention imaging element arrangements at prescribed intervals; and a correction calculation part 19 for calculating the inclination of the display device 6 to an optical axis of the imaging device 3 from a difference with the optimum imaging distance of the first and second attention image element arrangements and a distance between positions on the display device 6 corresponding to the first and second attention imaging element arrangements by specifying the optimum evaluation value having the minimum unevenness out of calculated evaluation values and calculating the optimum imaging distance leading to calculating the optimum evaluation values concerning the first and second attention imaging element arrangements. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a display device inspection method and an inspection apparatus in a manufacturing process of a display device such as a liquid crystal panel, and more particularly to an inspection method and an inspection apparatus for imaging a display device under an imaging condition with less occurrence of moire. Is.

  A display device such as a liquid crystal panel is turned on in the latter half of the manufacturing process, and its quality is inspected. This inspection includes a visual inspection in which the illuminated display device is visually inspected by an operator, and an automatic inspection in which a signal obtained by imaging the illuminated display device with a camera such as a line sensor or an area sensor is processed. There is.

  However, in the case of visual inspection, there are variations in determination due to oversight or individual differences. Furthermore, display devices have recently become higher in definition, and the number of display pixels (with three picture elements R, G, B as one unit) is on the order of millions of pixels. It is difficult to accurately record the found defect position and defect type and provide feedback information for defect correction and process improvement. The picture element generally has a ratio of horizontal size to vertical size of about 1: 3.

  On the other hand, in the case of automatic inspection, since a target display device is imaged using a camera, the imaging magnification (the ratio between the number of display pixels of the display device and the number of elements of the image sensor) It is necessary to set the imaging condition so that the state of imaging one pixel of (3) with the number of imaging elements of 3 × 3 is referred to as imaging magnification 3). Furthermore, in order to perform the inspection under the same conditions in the entire area of the display device, it is necessary to make the imaging conditions, that is, the imaging magnification equal in the entire area.

  However, in general, the setting of the imaging magnification requires a mechanism such as a scale and a jig for holding it, and the setting time is limited to the time of introduction of the apparatus or maintenance of the manufacturing process. There is a problem that it is not possible to immediately cope with a shift in imaging magnification due to a factor change or registration of a new model.

  Also, from the viewpoint of inspection accuracy, in the manufacturing process of large display devices such as those used in LCD TVs, the tact (time required to manufacture one product) is severely limited. Macro inspection that adjusts the imaging magnification to about 3 or 6 has become the mainstream. When the imaging magnification is 3, the imaging resolution is the horizontal size of the pixel. When the imaging magnification is 6, the imaging resolution is ½ of the horizontal size of the pixel.

  With such a magnification, the following problems occur. A display device such as a liquid crystal panel has a structure in which picture elements such as RGB are regularly arranged. In this picture element, RGB filters are regularly arranged on a glass substrate, and a black matrix (hereinafter referred to as BM) is arranged in the gap between the filters so as to prevent light from leaking. . When such a display device is imaged by a camera, captured image data is obtained by sampling regularly arranged display picture elements in the display device with an image sensor regularly arranged in the camera. At this time, since both the display picture element and the image sensor have a regular lattice pattern, a frequency component corresponding to the difference between the spatial frequencies of the two patterns is generated, and a moire is generated. When detecting a pixel defect such as a bright spot or a black spot or a line defect, the moire becomes a noise component, which lowers the inspection accuracy.

  Therefore, in general, in order to suppress the moire component and improve the inspection accuracy, the setting accuracy of the imaging magnification is precisely set, and the number of imaging elements for p display pixels is accurately an integer in the entire area of the display device. Magnification is required. However, it is difficult to make and maintain such an accurate setting in the manufacturing process. For this reason, various methods have been proposed for the above problem.

  In the invention described in Japanese Patent Laid-Open No. 2004-228561, the image sensor t area is arranged so as to correspond to the area of the display picture element s, and the displacement is made by a displacement amount of 1 / n of the image sensor pitch. By picking up an image and adopting a detection value having a large detection value by comprehensively looking at the detection value in each state, a detection value with reduced influence of moire is obtained.

  In the invention described in Patent Document 2, the screen of the image display device is captured by the camera, the video signal of the screen is analyzed, and the focal length of the camera is automatically set to a distance that minimizes the moire component based on the analysis result. It is matched.

A technique for controlling the angle between the optical axis of the camera lens and the focal plane of the imaging target is disclosed in, for example, Patent Document 3.
JP 7-83799 A (published on March 31, 1995) Japanese Patent Laid-Open No. 4-339489 (released on November 26, 1992) JP 7-142346 A (released on June 2, 1995)

  However, the following problems occur in the prior art.

  In the invention described in Patent Document 1, only a configuration for changing a preferable correspondence (relative position between pixels) between a display picture element and a sensor pixel is described, and a configuration for automatically setting a preferable imaging magnification is described. Not listed. The invention described in Patent Document 1 does not include means for correcting the angle between the optical axis of the lens and the focal plane.

  Further, in the invention described in Patent Document 2, the focal length of the camera is automatically adjusted to the distance that minimizes the moire component based on the result of analyzing the imaging data obtained by imaging the display device. Alternatively, when the camera is tilted, it is possible to set a condition that minimizes the moire component in a certain area, but it is not possible to set it in the entire area. Further, adjusting the focal length to a distance that minimizes the moire component means that the focal point of the camera is shifted from the in-focus position, and the defect detection sensitivity is significantly reduced.

  The present invention has been made in order to solve the above-described problems, and its purpose is to set the imaging magnification of the imaging means so that the moire component is reduced without stopping the production line in the inspection apparatus in the manufacturing process. It is an object of the present invention to provide an inspection apparatus that automatically performs the imaging conditions in the entire area of the display device by correcting the inclination of the display device with respect to the optical axis of the imaging means.

  In order to solve the above problem, an inspection apparatus according to the present invention images a display device having picture elements arranged in a certain direction by an imaging means having an image sensor arranged along the arrangement direction of the picture elements. An inspection apparatus for determining the quality of the display device by analyzing the obtained captured image, and imaging the display device a plurality of times while changing an imaging distance between the imaging means and the display device An image pickup control means for controlling the image pickup means, and an array of image pickup elements for picking up a picked-up image of the display device, and of the array of image pickup elements arranged in a direction along the pixel array direction. The pixel values output from the image pickup elements included in the first target image pickup element array, which is an array of image pickup elements to be extracted, are extracted at predetermined intervals, and evaluation values indicating variations in the extracted pixel values are picked up. Calculation is performed for each image, and pixel values output from image sensors included in the second target image sensor array parallel to the first target image sensor array are extracted at predetermined intervals, and variations in the extracted pixel values are calculated. An evaluation value calculation unit that calculates an evaluation value to be shown for each captured image, and an evaluation value that has the smallest degree of variation among the evaluation values calculated by the evaluation value calculation unit is specified and the optimal evaluation value is calculated. Evaluation value comparison means for calculating the optimum imaging distance, which is the reached imaging distance, with respect to the first and second attention image sensor arrays, the optimum imaging distance of the first attention image sensor array, and the optimum of the second attention image sensor array From the difference between the imaging distance and the distance between the position on the display device corresponding to the first target image sensor array and the position on the display device corresponding to the second target image sensor array, Is characterized by comprising a slope calculation means for calculating an inclination of the display device with respect to the optical axis of the image means.

  In order to solve the above problems, an inspection method according to the present invention images a display device having picture elements arranged in a certain direction by an imaging means having an image sensor arranged along the arrangement direction of the picture elements. An inspection method in an inspection apparatus that determines the quality of the display device by analyzing the obtained captured image, wherein the display device is changed while changing an imaging distance between the imaging means and the display device. An imaging element of interest that is an array of imaging elements that captures an image captured by the display device and captures the captured image of the display device in a direction along the direction in which the picture elements are aligned. When pixel values output from image sensors included in the first target image sensor array, which is an array of elements, are extracted at predetermined intervals, and an evaluation value indicating variation in the extracted pixel values is calculated In addition, pixel values output from the image sensors included in the second target image sensor array parallel to the first target image sensor array are extracted at predetermined intervals, and evaluation values indicating variations in the extracted pixel values are obtained. Of the evaluation value calculation step to be calculated and the evaluation value calculated in the evaluation value calculation step, the optimal evaluation value with the smallest degree of variation is identified, and the optimal imaging that is the imaging distance that led to the calculation of the optimal evaluation value An evaluation value comparison step of calculating a distance with respect to the first and second image pickup element arrays, a difference between an optimum image pickup distance of the first image pickup element array and the optimum image pickup distance of the second image pickup element array; From the distance between the position on the display device corresponding to the first target image sensor array and the position on the display device corresponding to the second target image sensor array, the display device with respect to the optical axis of the image pickup means. It is characterized in that it comprises a slope calculation step of calculating a scan of tilt.

  According to the above configuration, the imaging device under the control of the imaging control unit performs imaging of the display device a plurality of times while changing the imaging distance. The evaluation value calculation means extracts pixel values output from the image sensors included in the first and second target image sensor arrays at predetermined intervals, and uses the evaluation values indicating variations in the extracted pixel values as target image sensors. Calculation is performed for each array and for each of a plurality of captured images obtained by a plurality of times of imaging.

  Here, the noticeable image sensor array is an array of image sensors that captures a captured image of a display device, and is an array of image sensors that are arranged in a direction along the direction in which picture elements are arranged. Among the image sensor arrays, a certain image sensor array of interest is referred to as a first target image sensor array, and another image sensor array parallel to the first target image sensor array is referred to as a second target image sensor array. . Note that the number of the imaging element arrays of interest may be at least two and may be three or more.

  Then, the evaluation value comparison means obtains the optimum evaluation value with the least variation among the evaluation values calculated by the evaluation value calculation means, and at the optimum imaging distance that is the imaging distance that led to the calculation of the optimum evaluation value. A certain optimum imaging distance is calculated with respect to the first and second attention imaging element arrays.

  The inclination calculating means corresponds to the difference between the optimal imaging distance of the first target image sensor array and the optimal image distance of the second target image sensor array (hereinafter referred to as the first distance) and the first target image sensor array. And the distance between the position on the display device and the position on the display device corresponding to the second attention image sensor array (hereinafter referred to as the second distance), calculate.

  In other words, the first distance is the position on the display device corresponding to the first target image sensor array and the display device corresponding to the second target image sensor array in the direction of the coordinate axis parallel to the optical axis of the imaging means. It is the distance between the positions. If the first distance and the second distance are obtained, the inclination of the display device with respect to the optical axis of the imaging means can be calculated by geometric calculation using sin. And if this inclination is found, the inclination of the display device with respect to the optical axis of the imaging means can be corrected.

  Therefore, with the above configuration, it is possible to set an optimal imaging distance that reduces the amount of moire components included in the captured image, and to correct the tilt of the display device with respect to the optical axis of the imaging means, thereby capturing an image in the entire area of the display device. Conditions can be made equal.

  Further, when the imaging magnification of the imaging means is expressed as a magnification at which p picture elements are imaged by q image sensors, the predetermined interval is the smallest integer among natural multiples of q / p. It is preferable that the number is multiplied by the number of picture elements constituting the pixels of the display device.

  According to the above configuration, optimum pixel value extraction is performed at an ideal imaging magnification such that the ratio of q imaging elements to p picture elements is the smallest integer. Therefore, the imaging distance can be changed so as to approach the ideal imaging magnification.

  Also included in the technical scope of the present invention are an inspection program for causing a computer to function as each means of the inspection apparatus and a computer-readable recording medium on which the inspection program is recorded.

  As described above, the inspection apparatus according to the present invention includes an imaging control unit that controls the imaging unit to image the display device a plurality of times while changing an imaging distance between the imaging unit and the display device. An array of image sensors that captures a captured image of a display device, and is included in a first target image sensor array, which is an array of image sensors of interest, out of an array of image sensors arranged in a direction along the pixel array direction The pixel values output from the image sensor to be extracted are extracted at predetermined intervals, the evaluation value indicating the variation of the extracted pixel values is calculated for each captured image, and the second target parallel to the first target image sensor array is calculated. Evaluation value calculation means for extracting pixel values output from the image sensors included in the image sensor array at predetermined intervals, and calculating evaluation values indicating variations in the extracted pixel values for each captured image, and the evaluation value calculation Among the evaluation values calculated by the means, the optimum evaluation value with the smallest degree of variation is specified, and the optimum imaging distance, which is the imaging distance that led to the calculation of the optimum evaluation value, is set as the first and second noted imaging element arrays. Evaluation value comparison means for calculating the difference between the optimal imaging distance of the first target image sensor array and the optimal image distance of the second target image sensor array, and the display device corresponding to the first target image sensor array And an inclination calculating means for calculating the inclination of the display device with respect to the optical axis of the imaging means from the distance between the position of the imaging device and the position on the display device corresponding to the second image pickup device array. .

  As described above, the inspection method according to the present invention changes the imaging distance between the imaging means and the display device, captures the display device a plurality of times, and captures an image of the display device each time the image is captured. Of the imaging elements that are taken in the image, and output from the imaging elements included in the first noted imaging element array, which is an array of imaging elements of interest, among the imaging element arrangements arranged in a direction along the arrangement direction of the picture elements. Pixel values to be extracted at predetermined intervals, evaluation values indicating variations of the extracted pixel values are calculated, and from the image sensors included in the second target image sensor array parallel to the first target image sensor array The pixel value to be output is extracted at a predetermined interval, the evaluation value calculating step for calculating the evaluation value indicating the variation of the extracted pixel value, and the variation among the evaluation values calculated in the evaluation value calculating step An evaluation value comparing step of identifying an optimum evaluation value having a small match and calculating an optimum imaging distance, which is an imaging distance for calculating the optimum evaluation value, with respect to the first and second attention image sensor arrays; Corresponding to the difference between the optimal imaging distance of the target image sensor array and the optimal imaging distance of the second target image sensor array, the position on the display device corresponding to the first target image sensor array, and the second target image sensor array And a tilt calculating step of calculating the tilt of the display device with respect to the optical axis of the imaging means from the distance between the display device and the position on the display device.

  Therefore, the imaging magnification of the imaging means can be set so that the occurrence of moire is suppressed, and the imaging conditions are made equal in the entire area of the display device by correcting the inclination of the display device with respect to the optical axis of the imaging means. There is an effect that can be.

  The following describes one embodiment of the present invention with reference to FIGS.

(Configuration of the inspection apparatus 1)
FIG. 2 is a schematic diagram illustrating an example of the configuration of the inspection apparatus 1 according to the present embodiment. As shown in FIG. 2, the inspection apparatus 1 includes an angle / imaging distance adjustment mechanism 2, an imaging apparatus 3, a focus adjustment mechanism 4 that controls a focal length, a lens 5, and a contact unit 7 that is connected to a display device 6 to be inspected. , Illumination 8, stage 9 on which display device 6 is placed, lighting circuit 10 that supplies a drive signal to display device 6, and control device 11.

  The angle / imaging distance adjusting mechanism 2 adjusts the imaging distance between the imaging device 3 and the display device 6 and controls the angle between the optical axis of the lens 5 and the focal plane (hereinafter referred to as the tilt angle). . The angle / imaging distance adjusting mechanism 2 includes an imaging distance adjusting mechanism 2a and an angle adjusting mechanism 2b, and details thereof will be described later.

  The imaging device 3 is for imaging the display device 6, and has a plurality of imaging elements arranged in a matrix. Examples of the imaging device 3 include a CCD (Charge Coupled Devices) camera and a CMOS (Complementary Metal-Oxide-Semiconductor) camera according to the type of element. In addition, according to the imaging type, an area sensor camera and a line sensor camera can be exemplified.

  The control device 11 controls the inspection device 1. FIG. 1 is a functional block diagram showing the configuration of the control device 11. As shown in FIG. 1, the control device 11 includes an imaging distance adjustment unit 12, an angle adjustment unit 13, an imaging device control unit 14 (imaging control unit), a rotation deviation correction unit 15, and a resolution evaluation value calculation unit 16 (evaluation value calculation). Means), a correction value calculation unit 19 (evaluation value comparison unit, inclination calculation unit) and an inspection unit 20.

  The imaging distance adjustment unit 12 adjusts the imaging distance of the imaging device 3 by controlling the imaging distance adjustment mechanism 2 a of the angle / imaging distance adjustment mechanism 2.

  The angle adjustment unit 13 adjusts the tilt angle of the imaging device 3 by controlling the angle adjustment mechanism 2 b of the angle / imaging distance adjustment mechanism 2.

  The imaging device control unit 14 controls the operation of the imaging device 3. For example, the imaging device control unit 14 controls the focus of the imaging device 3 via the focus adjustment mechanism 4. Further, the imaging device control unit 14 receives the captured image (imaging data) of the display device 6 acquired by the imaging device 3 and outputs the captured image to the resolution evaluation value calculation unit 16.

  The rotation deviation correction unit 15 controls the stage 9 to correct the rotation deviation of the display device 6 around the optical axis. This correction method may be a known method. For example, the imaging device 3 captures an outer frame or a specific lighting pattern of the display device 6, calculates the position (angle) of the display device 6 in the imaging range of the imaging device 3 from the acquired image, and corrects rotational deviation. Can be done.

  The resolution evaluation value calculation unit 16 analyzes a captured image obtained by capturing the display device 6, thereby calculating a resolution evaluation value for evaluating the imaging resolution of the captured image. In other words, this resolution evaluation value is an evaluation value for evaluating the positional relationship between the picture element of the display device 6 and the image pickup device of the image pickup apparatus 3. Since the imaging resolution changes depending on the imaging distance, it can be said that the resolution evaluation value calculation unit 16 calculates an evaluation value for evaluating whether the imaging distance is appropriate. The resolution evaluation value calculation unit 16 includes an output signal extraction unit 17 and a calculation unit 18.

  The output signal extraction unit 17 receives a captured image of the display device 6 output from the imaging device control unit 14 and forms a specific imaging element array (target imaging element array) (hereinafter referred to as an imaging element array) that forms the captured image. Pixel values output by Amn (m = 0, 1, 2,...) (Referred to as n = 0, 1, 2,...) Are extracted at predetermined intervals.

  Here, the image sensor array is an array of image sensors that captures a picture element array in a horizontal picture element array direction or a vertical picture element array direction of the display device 6 described later. One captured image is formed by an image sensor array A corresponding to a plurality of picture element arrays, and the number assigned to each of these image sensor arrays is represented by a value of m. The value of n is the number of times the imaging distance is changed.

  As will be described later, after the relative position between the display device 6 and the imaging device 3 is adjusted so that the arrangement of the picture elements of the display device 6 and the arrangement of the imaging elements of the imaging device 3 are substantially parallel to each other. Since the display device 6 is imaged, the image sensor array A is an image sensor array that images at least a part of a certain pixel array.

  The predetermined interval is q / p × 3 × s when one pixel is composed of three picture elements and when p image elements of the display device 6 are picked up by q image pickup elements. The value (s is a natural number) (hereinafter referred to as an interval evaluation value) is the smallest integer. In other words, when the imaging magnification of the imaging device 3 is expressed as a magnification at which p picture elements are imaged by q imaging elements, the predetermined interval is the smallest integer among natural multiples of q / p. And the number of picture elements constituting the pixels of the display device 6.

  For example, when p = 1 and q = 1, the interval evaluation value is the smallest integer 3 when s = 1, so the extraction interval is set to 3. Also, when p = 1 and q = 1.5, the smallest integer 9 is obtained when s = 2, so the extraction interval is set to 9.

  The values of p and q may be stored in a memory included in the output signal extraction unit 17, or may be input by a user from an input unit (not shown) provided in the control device 11. Further, the interval evaluation value itself may be stored or input instead of the values of p and q.

  The pixel value extraction in the output signal extraction unit 17 will be described in detail later.

  The calculation unit 18 calculates a resolution evaluation value Bmn (n = 0, 1, 2,...) From the set of pixel values output from the output signal extraction unit 17. N is the number of times the imaging distance is changed. A method for calculating the resolution evaluation value Bmn will be described later.

  When the first resolution evaluation value Bm0 is calculated for the imaging element array Amn, the resolution evaluation value calculation unit 16 changes the imaging distance by a predetermined distance and calculates the second resolution evaluation value Bm1. At this time, the resolution evaluation value calculation unit 16 calculates an imaging distance Cmn that is a distance between the specific imaging element of the imaging device 3 and the display device 6. After performing such processing a plurality of times within a predetermined imaging distance range, the resolution evaluation value calculation unit 16 calculates the calculated plurality of resolution evaluation values Bmn and the corresponding imaging distance Cmn as a correction value calculation unit. 19 output. A method for calculating the predetermined distance and the imaging distance Cmn will be described later.

  The correction value calculation unit 19 calculates an optimum imaging distance and tilt angle using the plurality of resolution evaluation values Bmn output from the resolution evaluation value calculation unit 16 and the imaging distance Cmn corresponding thereto. These calculation methods will be described later.

  The inspection unit 20 determines the quality of the display device 6 by analyzing the imaging data of the display device 6. The inspection method in the inspection unit 20 is not particularly limited, and an appropriate method may be selected from known inspection methods.

(Configuration of angle / imaging distance adjusting mechanism 2)
FIG. 3 shows an embodiment of the angle / imaging distance adjusting mechanism 2 for adjusting the imaging distance and the tilt angle. 3A shows the display device 6, the imaging device 3, and the angle / imaging distance adjusting mechanism 2 as viewed from the side (Y-axis direction in FIG. 3), and FIG. It is seen from (X-axis direction in FIG. 3).

  3A and 3B show a state in which the display device 6 is not orthogonal to the optical axis of the lens 5 but is inclined with respect to the optical axis. The imaging distance between the imaging device 3 and the display device 6 is the distance of the center line of the optical axis connecting the tip of the lens 5 and the display device 6. The imaging distance may be a distance from the imaging element surface of the imaging device 3 to the display device 6.

  As shown in FIG. 3A, the angle / imaging distance adjusting mechanism 2 includes an imaging distance adjusting mechanism 2a and an angle adjusting mechanism 2b. The imaging distance adjustment mechanism 2a adjusts the imaging distance between the imaging device 3 and the display device 6 (the distance in the Z-axis direction in FIG. 3). Further, the inclination of the display device 6 with respect to the optical axis of the lens 5 is adjusted by the angle adjusting mechanism 2b.

  In FIG. 2A, the upper and lower inclinations (upper and lower tilts) of the display device 6 with respect to the optical axis are shown. However, the tilt in the direction perpendicular to the upper and lower tilts (the tilt on the left and right of the display device) may be adjusted. . Further, the angle adjustment mechanism 2b may be provided on the display device 6 side as shown in FIG.

(Configuration of display device 6)
Next, the configuration of the display device 6 (inspected object) to be inspected by the inspection apparatus 1 will be described with reference to FIG. FIG. 4 is a schematic diagram showing the configuration of the display device 6.

  The display device 6 is a color filter in which picture elements 6a to 6c of three colors R (red), G (green), and B (blue) are arranged in a matrix. As shown in FIG. 4, each of the plurality of rectangles represents a picture element, and a repetitive array of R picture element 6a, G picture element 6b, and B picture element 6c is formed in a line on the filter. Such a direction of picture element arrangement is referred to as a picture element arrangement direction. In this picture element arrangement direction, a horizontal picture element arrangement direction parallel to the short side of the picture element (the direction of arrow 21 in FIG. 4) and a horizontal picture element arrangement direction perpendicular to the short side of the picture element (arrow in FIG. 4). 22 directions).

  The distance between the picture elements in the horizontal picture element arrangement direction is referred to as a picture element pitch. More precisely, the picture element pitch is a distance between the center line 23 of the picture element perpendicular to the horizontal picture element arrangement direction and the center line 24 of the picture element adjacent to the picture element. Between each picture element, BM which is a light absorptive film | membrane is exposed.

  When imaging such a display device 6, the imaging device is arranged such that the pixel arrangement direction and the imaging element arrangement direction of the imaging device 3 are parallel (there is no rotational deviation about the optical axis). 3 is arranged. In FIG. 4, a lattice 25 indicates an imaging range of each imaging element. The imaging range of each imaging element is substantially square, and the length of one side of this square is called imaging resolution. In FIG. 4, the imaging resolution is slightly smaller than the picture element pitch.

(Example of image sensor output signal)
Next, an example of an output signal of the image sensor obtained when the display device 6 is imaged will be described with reference to FIG. FIG. 4A shows an output signal of the image sensor obtained when the imaging resolution is 1.5% smaller than the pixel pitch, and FIG. 4B shows the imaging resolution 21.5% larger than the pixel pitch. The output signal of the image pick-up element obtained when it is small is shown. FIG. 3C shows an output signal of the image sensor obtained when the imaging resolution is equal to the pixel pitch (imaging magnification 3). 5A, 5B, and 5C show one line of the output signal of the image sensor in the horizontal picture element array direction of the display device 6 (for example, a round frame in FIG. 4).

  As shown in FIG. 5A, moire is generated as a low-frequency component when the image is picked up with a resolution close to the pixel pitch. On the other hand, as shown in FIG. 5B, moire is generated as a high-frequency component when imaging is performed with such a resolution that the difference between the imaging resolution and the pixel pitch is large. On the other hand, as shown in FIG. 5C, it is understood that moire does not occur when imaging is performed with a resolution such that the imaging resolution is equal to the pixel pitch. As described above, the moiré pattern changes depending on the resolution of the imaging device 3. Such moire prevents accurate detection of defects in the display device 6.

(Calculation method of resolution evaluation value)
Next, a method for calculating the resolution evaluation value Bmn in the resolution evaluation value calculation unit 16 will be described with reference to FIG. FIG. 6 is a diagram for explaining a method for calculating a resolution evaluation value in the resolution evaluation value calculation unit 16. FIG. 6A shows a horizontal imaging element array Amn (intermediate horizontal) corresponding to the center of the captured image among the imaging element arrays obtained by imaging the display device 6 having RGB picture element arrays by the imaging apparatus 3. Line) (first attention image sensor array). Assume that the pixel value (luminance value) profile for this image sensor array Amn is as shown in FIG. 6B. FIG. 6B is a graph showing the luminance values of the pixels included in the image sensor array Amn.

  The state shown in FIG. 6B is a state in which the imaging magnification is not accurately an integer magnification, and it can be seen that three moire components (frequency components) are generated. Here, the state in which the imaging magnification is an integer magnification means that the number of imaging elements of the imaging device 3 is q with respect to p display pixels of the display device 6 with respect to the horizontal pixel arrangement direction or the vertical picture element arrangement direction. The assigned state, where p and q are positive integers. In other words, the state in which the imaging magnification is an integer magnification is a state in which p display pixels are imaged by q imaging elements.

  On the other hand, the state shown in FIG. 6C is a state in which the imaging magnification is accurately an integer magnification (magnification = 3) (images are captured with a resolution such that the imaging resolution and the pixel pitch are equal). State). If the set imaging magnification is 3 (three image sensors are allocated to one display pixel), one image sensor is allocated to the display picture element horizontal size (the width of the picture element in the horizontal picture element arrangement direction). It becomes a state. Therefore, the output value of the image sensor (pixel value of the image data) is used every q / p = 3/1 = 3. For example, a frequency component (profile) indicated by a round frame in FIG.

  Therefore, in the above case, the output signal extraction unit 17 extracts the pixel values of a specific imaging element array Amn (m = 0, 1, 2,...) That forms imaging data, every three.

  In the state of FIG. 6B, there are three imaging element array profiles extracted for every three pixels, but only one may be used for evaluation of imaging resolution. That is, the output signal extraction unit 17 may extract at least one of a plurality of frequency components included in the imaging data.

Next, using the set of pixel values extracted by the output signal extraction unit 17, the calculation unit 18 calculates a resolution evaluation value Bmn. The resolution evaluation value is, for example, the sum of absolute values of differences between pixel values of adjacent picture elements captured by the image sensor array Amn. That is, the evaluation formula used for calculating the resolution evaluation value Bmn is as follows when the number of each image sensor included in the image sensor array Amn is i (i = 0, 1, 2,...) 3) It can be expressed as an equation.
Bmn (0) = Σ | A3 (i + 1) n−A3in | (1)
Bmn (1) = Σ | A3 (i + 1 + 1) n−A3 (i + 1) n | (2)
Bmn (2) = Σ | A3 (i + 2 + 1) n−A3 (i + 2) n | (3)
The computing unit 18 may calculate the resolution evaluation value using at least one of the above expressions (1) to (3). The above formulas (1) to (3) are formulas used when extracting pixel values of a specific imaging element array Amn that forms imaging data every three, and the interval between the pixel values to be extracted is used. In addition, the above formula may be changed as appropriate.

  Further, in order to simply evaluate the luminance variation, the variance or the standard deviation may be used as the evaluation value.

  When these evaluation formulas are used, the minimum value Bmn = 0 in the state shown in FIG.

  Here, assuming that the imaging magnification is 6, six imaging elements are assigned to one display pixel. Therefore, the output value of the image sensor array is used for every q / p = 6/1 = 6.

  Furthermore, it is possible to adjust the imaging magnification to a non-integer multiple. For example, if it is desired to set the imaging magnification to 4.5, 4.5 image sensors are assigned to one display pixel, that is, 9 image sensors are assigned to 2 display pixels. Therefore, the value of the image sensor array is used for every nine.

(Image distance and tilt angle correction method)
Next, a more specific calculation method of the resolution evaluation value Bmn in the resolution evaluation value calculation unit 16 and a tilt angle calculation method in the correction value calculation unit 19 will be described. FIG. 7 is a diagram for explaining a tilt angle calculation method. FIG. 7A is a diagram illustrating the inclination of the display device 6 with respect to the optical axis of the imaging device 3. In the following, when the display device 6 is tilted without being orthogonal to the optical axis of the imaging device 3 (lens 5), as shown in FIG. A case will be described where the imaging device 3 is far away and the lower part of the display device 6 is approaching the imaging device 3.

  FIG. 7B is a diagram illustrating an upper horizontal line (second attention image sensor array) and an intermediate horizontal line (first attention image sensor array) in a captured image of the display device 6. In this case, as shown in FIG. 7B, the resolution evaluation value calculation unit 16 has a horizontal imaging element array A0n (intermediate part horizontal) corresponding to an intermediate part located between the upper part and the lower part of the display device 6. Resolution evaluation values B0n and B1n are calculated for the horizontal imaging element array A1n (upper horizontal line) corresponding to the upper portion while changing the imaging distance. At the same time, the imaging distances C0n and C1n at that time are also calculated. The resolution evaluation value calculation unit 16 executes such processing for an imaging distance within a predetermined range.

  As a method for measuring the imaging distance Cmn, for example, the method described in Patent Document 3 can be used, but other methods may be used.

  Note that the interval at which the imaging distance is changed is not particularly limited. The predetermined range may be a range that includes at least one imaging distance that can be imaged with an imaging resolution that minimizes the resolution evaluation value Bmn. An appropriate range can be obtained by actually operating the inspection apparatus 1. You only have to set it.

  When the above operation is completed within a predetermined range, a graph as shown in FIG. 7C can be obtained. FIG. 7C is a graph showing the relationship between the imaging distance Cmn and the resolution evaluation value Bmn for the upper horizontal line and the intermediate horizontal line. That is, the relationship between the imaging distance Cmn and the resolution evaluation value Bmn for each of the upper horizontal line and the intermediate horizontal line becomes clear. In FIG. 7C, the imaging distance when the resolution evaluation value of the intermediate horizontal line is minimum (best) is defined as the imaging distance C0s, and the imaging distance when the resolution evaluation value of the upper horizontal line is minimum is defined as C1t. It is called.

FIG. 7D is a diagram for explaining a method of calculating the tilt angle. The tilt angle θ to be corrected at this time is, as shown in FIG. 7 (d), between the position on the display device 6 corresponding to the image sensor array A0n and the position on the display device 6 corresponding to the image sensor array A1n. And the difference between the imaging distance C1t and the imaging distance C0s (C1t−C0s),
sin θ = (C1t−C0s) / D01 (4)
Can be calculated as The correction value calculation unit 19 calculates the tilt angle using the above equation (4).

  The distance D01 is an initial setting value. The position on the display device 6 corresponding to the n-th imaging element array (n is a positive integer) may be set in advance. This setting may be realized by marking the outer frame of the display device 6 in advance or lighting markers at the four corners of the screen of the display device 6.

  The tilt angle calculated by the correction value calculation unit 19 is output to the angle adjustment mechanism 2b via the angle adjustment unit 13, and the angle adjustment mechanism 2b corrects the tilt of the display device 6 with respect to the optical axis based on the tilt angle. To do.

  Further, the correction value calculation unit 19 determines that the imaging distance C0s when the resolution evaluation value of the intermediate horizontal line is minimum is the optimum imaging distance (optimum imaging distance), and adjusts the imaging distance C0s. To the imaging distance adjusting mechanism 2a via the unit 12.

  Note that it is not always necessary to set the imaging distance when the resolution evaluation value of the intermediate horizontal line is minimum as the optimum imaging distance, and the horizontal line (the apex of the angle forming the angle θ) that is the base point for calculating the tilt angle The imaging distance when the resolution evaluation value of the horizontal line including the image data is minimized may be set as the optimum imaging distance.

(Rough flow of processing in the inspection device 1)
Next, an example of a rough flow of processing in the inspection apparatus 1 will be described with reference to FIG. FIG. 8 is a flowchart illustrating an example of a process flow in the inspection apparatus 1.

  First, based on the design data of the display device 6 input in advance and data of imaging conditions to be set, the control device 11 sets the imaging position, angle, and focus state of the imaging device 3 to the initial state (S1). ).

  Next, the rotation deviation correction unit 15 corrects the rotation deviation of the display device 6 around the optical axis (S2).

  When the correction of the rotation deviation is completed, the resolution evaluation value calculation unit 16 and the correction value calculation unit 19 calculate the setting value and the tilt angle of the optimum imaging distance for performing the inspection (S3).

  Then, based on the calculated tilt angle, the angle adjustment unit 13 corrects the tilt angle of the display device 6 via the angle adjustment mechanism 2b, and the imaging distance adjustment unit 12 solves the imaging distance adjustment mechanism 2a. The optimum imaging distance is set (S4).

  Thereafter, the control device 11 acquires imaging data of the display device 6 via the imaging device 3, analyzes the imaging data in the inspection unit 20, and determines whether the display device 6 is good or bad (S5). This determination result is notified to the user via a display unit (not shown) or the like.

(Processing flow for calculating the optimum imaging distance and tilt angle correction value)
Next, an example of a processing flow for calculating the optimum imaging distance and tilt angle will be described with reference to FIG. FIG. 9 is a flowchart illustrating an example of a process flow for calculating the optimum imaging distance and the tilt angle.

  First, the imaging device control unit 14 acquires a captured image of the display device 6 via the imaging device 3 (S31), and outputs the captured image to the output signal extraction unit 17 of the resolution evaluation value calculation unit 16.

  When the captured image is received, the output signal extraction unit 17 selects a specific imaging element array Amn (m = 0, 1, 2,...) (N = 0, 1, 2,...) That forms the captured image. ) Are extracted at predetermined intervals (for example, every three) (S32). The output signal extraction unit 17 performs this extraction on a plurality of image sensor arrays. The output signal extraction unit 17 outputs the set of extracted pixel values to the calculation unit 18.

  The calculation unit 18 calculates a resolution evaluation value Bmn corresponding to each imaging element array Amn using the set of pixel values extracted by the output signal extraction unit 17 and at least one of the above-described equations (1) to (3). (S33) (Evaluation Value Calculation Step) The calculation unit 18 stores the calculated resolution evaluation value Bmn in a temporary storage memory (not shown) provided in the resolution evaluation value calculation unit 16.

  When the calculation unit 18 finishes calculating the resolution evaluation value Bmn, the resolution evaluation value calculation unit 16 calculates the imaging distance Cmn at that time (S34). The calculated imaging distance Cmn is stored in the temporary storage memory together with the corresponding resolution evaluation value Bmn.

  Thereafter, the resolution evaluation value calculation unit 16 changes the imaging distance by a predetermined distance via the imaging device control unit 14 (S35), and repeats the above processing (returns to S31).

  When the resolution evaluation value calculation unit 16 repeats the above-described process over the entire predetermined range (YES in S36), a set of pairs of the resolution evaluation value Bmn and the imaging distance Cmn stored in the temporary storage memory is corrected. Output to the calculation unit 19.

  The correction value calculator 19 calculates the optimum imaging distance from the set of pairs of the resolution evaluation value Bmn and the imaging distance Cmn output from the resolution evaluation value calculator 16 as described above (evaluation value comparison step). Then, the tilt angle of the display device 6 is calculated (S37) (inclination calculating step).

  The correction value calculation unit 19 outputs the calculated tilt angle to the angle adjustment unit 13 and outputs the calculated optimum imaging distance to the imaging distance adjustment unit 12.

(Effect of inspection device 1)
As described above, according to the inspection apparatus 1, since the imaging apparatus 3 can be set to an appropriate imaging magnification without using a special scale or the like, a highly accurate inspection that eliminates the influence of moire is performed. be able to. At this time, there is an advantage that it is not necessary to stop the production line and it is not necessary to use a scale.

  In addition, it is possible to easily correct the tilt angle between the optical axis of the lens 5 and the focal plane of the front device 6, and the imaging conditions can be made equal over the entire area of the display device 6. Therefore, a highly accurate inspection can be performed on the entire area of the display device 6.

(Example of change)
The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

  Moreover, each block of the inspection apparatus 1 mentioned above, especially the control apparatus 11 may be comprised by hardware logic, and may be implement | achieved by software using CPU as follows.

  That is, the inspection device 1, particularly the control device 11, includes a CPU (central processing unit) that executes instructions of a control program that realizes each function, a ROM (read only memory) that stores the program, and a RAM ( random access memory), a storage device (recording medium) such as a memory for storing the program and various data. An object of the present invention is to provide a program code (execution format program, intermediate code program, source program) of a control program (inspection program) of the inspection apparatus 1 (particularly the control apparatus 11), which is software that realizes the above-described functions. The readable recording medium is supplied to the inspection apparatus 1 (particularly the control apparatus 11), and the computer (or CPU or MPU) reads and executes the program code recorded on the recording medium. Achievable.

  Examples of the recording medium include tapes such as magnetic tapes and cassette tapes, magnetic disks such as floppy (registered trademark) disks / hard disks, and disks including optical disks such as CD-ROM / MO / MD / DVD / CD-R. Card system such as IC card, IC card (including memory card) / optical card, or semiconductor memory system such as mask ROM / EPROM / EEPROM / flash ROM.

  Further, the inspection apparatus 1 (particularly the control apparatus 11) may be configured to be connectable to a communication network, and the program code may be supplied via the communication network. The communication network is not particularly limited. For example, the Internet, intranet, extranet, LAN, ISDN, VAN, CATV communication network, virtual private network, telephone line network, mobile communication network, satellite communication. A net or the like is available. Also, the transmission medium constituting the communication network is not particularly limited. For example, even in the case of wired such as IEEE 1394, USB, power line carrier, cable TV line, telephone line, ADSL line, etc., infrared rays such as IrDA and remote control, Bluetooth ( (Registered trademark), 802.11 wireless, HDR, mobile phone network, satellite line, terrestrial digital network, and the like can also be used. The present invention can also be realized in the form of a computer data signal embedded in a carrier wave in which the program code is embodied by electronic transmission.

  The present invention can also be expressed as follows. That is, the display device inspection method of the present invention is an inspection method in which a display screen of a display device is imaged by a camera equipped with an imaging device, and the quality of the display device is determined by the obtained imaging data. An imaging device that automatically sets the imaging distance between devices and corrects the angle (tilt) between the optical axis of the lens and the focal plane, and corresponds to p display pixels for positive integers p and q that cannot be divided from each other. a method of automatically setting a relationship between q and a desired relationship in the entire region of the display device, the step of controlling the imaging distance, the step of controlling the angle between the optical axis of the lens and the focal plane, Calculating a resolution evaluation value from a plurality of horizontal or vertical image sensor arrays of the imaging data while changing the imaging distance; and an imaging distance of the plurality of horizontal or vertical image sensor arrays. From the imaging distance at the time of the best value among the resolution evaluation values and the distance relationship on the display device of the plurality of horizontal or vertical imaging element arrays, the imaging distance setting of the camera and the optical axis of the lens And an angle correction process with respect to the focal plane.

  Further, the step of calculating the resolution evaluation value from the plurality of horizontal or vertical imaging element arrays of the imaging data while changing the imaging distance may be performed with respect to the horizontal or vertical direction of the display pixel array of the display device. Among the detection values of the corresponding image sensor array, when q / p is an integer when q × q image sensors are assigned to each p pixels of the display pixel, It is preferable that the resolution evaluation value is calculated using the detection value of the image sensor for each q / p. However, p and q are positive integers.

  Further, the step of calculating the resolution evaluation value from the plurality of horizontal or vertical imaging element arrays of the imaging data while changing the imaging distance is performed in the horizontal direction or the vertical direction of the display picture element array of the display device. On the other hand, when q / p is a non-integer when the imaging condition setting for allocating q image sensors to each p of the display pixels among the detection values of the image sensor array corresponding thereto, the image sensor array It is preferable that the resolution evaluation value is calculated using the detection value of the imaging element for each q in the above. However, p and q are positive integers.

  The step of calculating the resolution evaluation value from a plurality of horizontal or vertical imaging element arrays of the imaging data while changing the imaging distance evaluates the degree of variation in the detection value of the imaging element array that satisfies the condition. The resolution evaluation value and the imaging distance are calculated for each of the plurality of horizontal or vertical imaging element arrays on the condition that a better evaluation formula is used as the degree of variation in the detection values of the imaging element arrays that meet the above conditions decreases. It is preferable.

  The imaging distance at the time of the best value among the resolution evaluation values for the imaging distances of the plurality of horizontal or vertical imaging element arrays and the display device of the plurality of horizontal or vertical imaging element arrays From the distance relationship, the steps of setting the imaging distance of the camera and correcting the angle (tilt) between the optical axis of the lens and the focal plane are arbitrary among a plurality of horizontal or vertical imaging element arrays. The step of setting the imaging distance when the resolution evaluation value is the best value for one imaging element array as the imaging distance, and the display of any one imaging element array and a plurality of horizontal or vertical imaging element arrays It is preferable to include a step of correcting the angle (tilt) between the optical axis of the lens and the focal point from the distance relationship on the device and the distance relationship between the imaging distances when the respective resolution evaluation values are the best values.

  An inspection apparatus for a display device according to the present invention is an inspection apparatus that images a display screen of a display device with a camera equipped with an image sensor, and determines whether the display device is good or bad with the obtained imaging data. The image pickup distance q and the angle (tilt) correction between the optical axis of the lens and the focal plane are automatically corrected, and q imaging elements corresponding to p display pixels for positive integers p and q that cannot be divided from each other. Is a device that automatically sets the relationship to the desired relationship in the entire region of the display device, the means for controlling the imaging distance, the means for controlling the angle between the optical axis of the lens and the focal plane, and the imaging distance Means for calculating a resolution evaluation value from a plurality of horizontal or vertical image sensor arrangements of the imaging data while changing the image data, and decomposition of the plurality of horizontal or vertical image sensor arrays for each imaging distance The imaging distance setting of the camera, the optical axis of the lens, and the focal point are determined from the imaging distance at the time of the best value among the evaluation values and the distance relationship on the display device of the plurality of horizontal or vertical imaging element arrays. Means for correcting the angle with the surface.

  Further, the means for calculating the resolution evaluation value from the plurality of horizontal or vertical imaging element arrays of the imaging data while changing the imaging distance is based on the horizontal or vertical direction of the display pixel array of the display device. Among the detection values of the corresponding image sensor array, when q / p is an integer when q × q image sensors are assigned to each p pixels of the display pixel, It is preferable that the resolution evaluation value is calculated using the detection value of the image sensor for each q / p.

  Further, the means for calculating the resolution evaluation value from the plurality of horizontal or vertical imaging element arrays of the imaging data while changing the imaging distance is arranged in the horizontal direction or the vertical direction of the display picture element array of the display device. On the other hand, when q / p is a non-integer when the imaging condition setting for allocating q image sensors to each p of the display pixels among the detection values of the image sensor array corresponding thereto, the image sensor array It is preferable that the resolution evaluation value is calculated using the detection value of the imaging element for each q in the above.

  The means for calculating a resolution evaluation value from a plurality of horizontal or vertical imaging element arrays of the imaging data while changing the imaging distance evaluates the degree of variation in the detection values of the imaging element array that meet the above condition. The resolution evaluation value and the imaging distance are calculated for each of the plurality of horizontal or vertical imaging element arrays on the condition that a better evaluation formula is used as the degree of variation in the detection values of the imaging element arrays that meet the above conditions decreases. It is preferable.

  The imaging distance at the time of the best value among the resolution evaluation values for the imaging distances of the plurality of horizontal or vertical imaging element arrays and the display device of the plurality of horizontal or vertical imaging element arrays Based on the distance relationship, the means for setting the imaging distance of the camera and correcting the angle (tilt) between the optical axis of the lens and the focal plane is an arbitrary one of a plurality of horizontal or vertical imaging element arrays. Means for setting the imaging distance when the resolution evaluation value is the best value for one imaging element array as the imaging distance, and display of any one imaging element array and a plurality of horizontal or vertical imaging element arrays It is preferable to comprise means for correcting the angle (tilt) between the optical axis of the lens and the focal plane from the distance relationship on the device and the distance relationship of the imaging distance when each resolution evaluation value is the best value.

  In the inspection process of a display device such as a liquid crystal panel, it can be used as an inspection apparatus that is not easily affected by moire and has high inspection accuracy.

It is a functional block diagram which shows the structure of the control apparatus with which the inspection apparatus which concerns on one Embodiment of this invention is provided. It is the schematic which shows the structure of the test | inspection apparatus which concerns on one Embodiment of this invention. It is a figure which shows the structure of the angle and imaging distance adjustment mechanism with which the inspection apparatus which concerns on one Embodiment of this invention is equipped, (a) is the figure which looked at the angle and imaging distance adjustment mechanism from the side, (b) These are views seen from above. It is the schematic which shows the structure of the display device which is a test object of the test | inspection apparatus which concerns on one Embodiment of this invention. The example of the output signal of the image pick-up element obtained when a display device is imaged is shown, (a) is the output signal of the image pick-up element obtained when the image pick-up resolution is 1.5% smaller than the pixel pitch. (B) is a diagram showing an output signal of the imaging device obtained when the imaging resolution is 21.5% smaller than the pixel pitch, and (c) is a diagram showing the imaging resolution as the pixel pitch. It is a figure which shows the output signal of the image pick-up element obtained when it is equal. It is a figure for demonstrating the calculation method of resolution evaluation value Bmn, (a) is the image pick-up element array Amn of the horizontal direction corresponding to the center of a picked-up image among the image pick-up element arrays which imaged the picked-up image of a display device. (B) is a graph showing the luminance values of the pixels included in the imaging element array Amn when the imaging magnification is not an integer magnification, and (c) is an accurate imaging magnification. It is a graph which shows the luminance value of the pixel contained in image pick-up element arrangement | sequence Amn when it is an integer magnification. It is a figure for demonstrating the calculation method of the correction value regarding a tilt angle, (a) is a figure which shows the inclination with respect to the optical axis of an imaging device of a display device, (b) is in the picked-up image of a display device. It is a diagram showing an upper horizontal line and an intermediate horizontal line, (c) is a graph showing the relationship between the imaging distance Cmn and the resolution evaluation value Bmn for the upper horizontal line and the intermediate horizontal line, (d), It is a figure for demonstrating the method of calculating a tilt angle. It is a flowchart which shows an example of the flow of a process in the inspection apparatus which concerns on one Embodiment of this invention. It is a flowchart which shows an example of the flow of a process for calculating an optimal imaging distance and tilt angle.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inspection apparatus 3 Imaging device (imaging means)
6 Display Device 6a Picture Element 6b Picture Element 6c Picture Element 14 Imaging Device Control Unit (Imaging Control Unit)
16 Resolution evaluation value calculation unit (Evaluation value calculation means)
19 Correction value calculation unit (evaluation value comparison means, inclination calculation means)

Claims (5)

A display device having picture elements arranged in a certain direction is imaged by an imaging means having an image sensor arranged in the arrangement direction of the picture elements, and the quality of the display device is determined by analyzing the obtained captured image. An inspection device for judging,
An imaging control means for controlling the imaging means to image the display device a plurality of times while changing an imaging distance between the imaging means and the display device;
First image pickup device array, which is an array of image pickup devices that picked up the picked-up images of the display device, and is an array of image pickup devices of interest among the array of image pickup devices arranged in a direction along the arrangement direction of the picture elements The pixel values output from the image sensor included in the image sensor are extracted at predetermined intervals, and an evaluation value indicating the variation of the extracted pixel value is calculated for each captured image, and the first parallel to the first target image sensor array is calculated. (2) an evaluation value calculation means for extracting pixel values output from image sensors included in the image sensor array of interest at predetermined intervals, and calculating an evaluation value indicating variation of the extracted pixel values for each captured image;
Among the evaluation values calculated by the evaluation value calculation means, the optimum evaluation value with the smallest degree of variation is specified, and the optimum imaging distance that is the imaging distance that led to the calculation of the optimum evaluation value is determined as the first and second. Evaluation value comparison means for calculating the image sensor array of interest;
The difference between the optimal imaging distance of the first target image sensor array and the optimal image distance of the second target image sensor array, the position on the display device corresponding to the first target image sensor array, and the second target image sensor An inspection apparatus comprising: an inclination calculating unit that calculates an inclination of the display device with respect to an optical axis of the imaging unit based on a distance between a position on the display device corresponding to the array and an optical axis of the imaging unit.   When the imaging magnification of the imaging means is expressed as the magnification at which p picture elements are imaged by the q imaging elements, the predetermined interval is the smallest integer among the multiples of q / p. The inspection apparatus according to claim 1, wherein the number of picture elements constituting the pixels of the display device is multiplied by the number.   The inspection program for functioning a computer as said each means of the inspection apparatus of Claim 1 or 2.   A computer-readable recording medium on which the inspection program according to claim 3 is recorded. A display device having picture elements arranged in a certain direction is imaged by an imaging means having an image sensor arranged in the arrangement direction of the picture elements, and the quality of the display device is determined by analyzing the obtained captured image. An inspection method in an inspection apparatus for judging,
While changing the imaging distance between the imaging means and the display device, each time the imaging is performed while imaging the display device, an array of imaging elements that capture the captured image of the display device, Pixel values output from image sensors included in the first target image sensor array, which is an array of target image sensors, are extracted at predetermined intervals from among the image sensor arrays arranged in the direction along the pixel array direction. And calculating an evaluation value indicating the variation of the extracted pixel value, and outputting pixel values output from the image sensor included in the second target image sensor array parallel to the first target image sensor array at a predetermined interval. An evaluation value calculating step of extracting and calculating an evaluation value indicating variation of the extracted pixel value;
Among the evaluation values calculated in the evaluation value calculation step, the optimum evaluation value with the smallest degree of variation is specified, and the optimum imaging distance that is the imaging distance that led to the calculation of the optimum evaluation value is determined as the first and second. An evaluation value comparison step for calculating the attention image sensor array;
The difference between the optimal imaging distance of the first target image sensor array and the optimal image distance of the second target image sensor array, the position on the display device corresponding to the first target image sensor array, and the second target image sensor An inspection method comprising: an inclination calculating step of calculating an inclination of the display device with respect to an optical axis of the imaging means based on a distance between a position on the display device corresponding to the array and an optical axis of the imaging means.

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