JP4312706B2 - Film thickness difference detection apparatus, film thickness difference detection method, color filter inspection apparatus, color filter inspection method - Google Patents

Description

  The present invention relates to a film thickness difference detecting apparatus, a film thickness difference detecting method, and a color filter for detecting a film thickness difference of a film having regularly arranged fine undulations, particularly a color filter formed by ejecting an ink material. The present invention relates to an inspection apparatus and a color filter inspection method.

  In recent years, the demand for liquid crystal display devices tends to increase and the demand for such devices increases. However, in order to further spread the liquid crystal display device, it is necessary to reduce the cost for manufacturing the liquid crystal display device.

  In particular, a color filter used for displaying a color image in a liquid crystal display device has a high manufacturing cost. Therefore, it is required to reduce the manufacturing cost of the color filter.

  In view of this, a method for forming a color filter by an ink jet method is attracting attention as satisfying the above requirements. In this forming method, R (red), G (green), and B (blue) picture elements are formed by ejecting ink from a nozzle head.

  The inkjet method is attracting attention because it is a manufacturing method with a small number of steps and high production efficiency. Further, according to this method, since ink can be applied only to a necessary region on the substrate on which the color filter is formed, the amount of ink used can be reduced, and as a result, the cost for forming the color filter can be reduced. It becomes possible to reduce.

  However, when forming a color filter in the ink jet system, there is a problem to be solved. That is, since the color filter is formed by ejecting ink from a plurality of nozzles, if there is a difference in the amount of ink ejected from each nozzle, a difference in film thickness occurs in a part of the color filter. Normally, this difference in film thickness is detected as unevenness in the direction in which the nozzles are arranged.

  In order to prevent display unevenness as a liquid crystal display device, it is necessary to suppress the relative difference in the thickness of the color filter within several tens of nm to several hundreds of nm. For this reason, an inspection method and an inspection apparatus for detecting a film thickness difference with a resolution of about several tens of nm to several hundreds of nm are required.

  As a method for detecting a film thickness difference, an optical film thickness inspection method is known. In this method, generally, a film thickness difference is measured by irradiating a film as an object to be inspected with light and detecting light transmitted through the film or reflected by the film.

  In the invention disclosed in Patent Document 1, first, the color filter formed by the ink jet method is irradiated with light, and the light transmitted through the region formed by the same nozzle is detected at multiple points at the same time by the line sensor, By obtaining the average value, the unevenness of the color filter is detected.

  On the other hand, in the invention disclosed in Patent Document 2, the coherent luminous flux of the light source is divided into two, one luminous flux is irradiated to the color filter at an angle close to horizontal, and the other is used as a reference luminous flux. The reflected light beam and the reference light beam are caused to interfere with each other, and the film thickness of the color filter is measured from the signal indicating the phase.

Further, in the invention disclosed in Patent Document 3, based on the result of measuring the refractive index of the object to be inspected, the object is irradiated with light so as to cause total reflection, and the totally reflected light is detected. Is used to analyze the shape of the surface of the inspection object.
JP 2003-269925 A (published September 25, 2003) JP 2000-121323 A (published April 28, 2000) JP-A-8-159979 (published on June 21, 1996)

  However, the above-described conventional configurations disclosed in Patent Documents 1 to 3 have the following problems.

  First, in order to detect a film thickness difference of about several tens to several hundreds of nanometers using light interference, it is necessary to use light having strong coherence such as laser light. As a result, there is a problem that the apparatus for irradiating coherent light becomes large.

  In addition, in order to measure a wide area using coherent light, it is necessary to irradiate light of a uniform intensity in the area, but such conditions must be satisfied when laser light is used. It is difficult. Therefore, it is necessary to perform parallel processing with a plurality of apparatuses, and there is a problem that it takes a lot of time to inspect the entire surface of a large substrate.

  In addition, measurement methods that do not use interfering light, such as total reflected light, require measurement of the refractive index of the object to be inspected, making the measurement method and measurement apparatus complicated, making it suitable for full-scale inspection of large substrates. There is no problem.

  The present invention has been made to solve the above-described problems, and its object is to form a film with a resolution of several tens to several hundreds of nanometers in a short time without complicating and increasing the size of the inspection apparatus. An object of the present invention is to provide a detection method and a detection apparatus for detecting a thickness difference.

  In order to solve the above problems, the film thickness difference detection apparatus according to the present invention is a film thickness difference detection apparatus for detecting a film thickness difference between undulations of a film having fine undulations regularly arranged on the surface. A light irradiating means for irradiating the surface with light at a predetermined inclination angle, an imaging means for imaging the film surface irradiated with light by the light irradiating means, and analyzing the captured image information imaged by the imaging means, Captured image information analysis means for calculating the brightness difference between the undulations, and film thickness difference estimation means for estimating the film thickness difference between the undulations on the film surface from the brightness difference calculated by the captured image information analysis means. It is characterized by that.

  In general, by irradiating a film having fine undulations regularly arranged on the surface with light at a predetermined inclination angle, the amount of reflected light at each undulation becomes uneven. For example, when the film thickness of a certain undulating portion is thinner than other undulating portions, the amount of light reflected from the undulating portion is smaller than the amount of light reflected from other undulating portions. On the contrary, when the film thickness of a certain undulating portion is larger than the film thickness of other undulating portions, the amount of reflected light from the undulating portion is larger than the amount of reflected light of the other undulating portions. By utilizing this principle to detect a difference in reflected light amount (brightness difference), it is possible to detect an undulating portion having a thickness different from that of other undulating portions.

  That is, if the film thickness difference between the undulations is estimated from the calculated luminance difference by the film thickness difference estimation means as in the above-described configuration of the present invention, the film thickness difference can be easily obtained with a simple configuration. It is possible to estimate.

  Here, it is possible to change the detection accuracy of the luminance difference to be detected by changing the inclination angle of the light irradiated by the light irradiation means. For example, in order to increase the detection accuracy of the brightness difference, it is preferable to irradiate light with undulations at an inclination angle that is as parallel as possible to the film surface.

  As described above, in the present invention, it is possible to easily increase the accuracy of detecting the luminance difference by adjusting the irradiation angle of the light irradiation means. Moreover, since this light irradiating means can use a normal light source, it can irradiate a wide range. That is, it is possible to cope with an increase in the size of the film surface to be inspected.

  Therefore, in the present invention, since the film thickness difference is not detected using the interference of light, it is not necessary to use light having a single wavelength such as laser light as in the prior art. As a result, even when the film thickness difference is detected on the order of several tens of nm to several hundreds of nm, it is only necessary to adjust the irradiation angle of the light irradiating means. As such, it does not lead to an increase in size or cost of the apparatus.

  It is preferable that the light irradiation angle of the light irradiation unit is adjusted so as to irradiate the curved surface having the maximum inclination angle among the curved surfaces of the undulations.

  Thereby, the film thickness difference can be detected with a resolution of about several tens of nanometers to several hundreds of nanometers in a short time without making the inspection apparatus complicated and large.

  Further, the storage unit stores reference information indicating a relationship between a preset luminance difference and a film thickness difference, and the film thickness difference estimation unit includes the luminance difference calculated by the captured image information analysis unit, The film thickness difference may be estimated with reference to the reference information stored in the storage unit.

  In this case, by preparing reference information for evaluating the relationship between the luminance difference and the film thickness difference in advance, it is possible to easily estimate the film thickness difference from the actually calculated luminance difference.

  A color filter formed by discharging a liquid color filter material onto a substrate can be considered as an example of a film having fine irregularities regularly arranged on the surface. In the case of such a color filter, a film thickness difference detecting device having the following configuration is used. In this case as well, the same operational effects as those obtained by the film thickness difference detection device can be obtained.

  That is, the film thickness difference detection apparatus of the present invention is the film thickness difference detection apparatus for detecting a film thickness difference of a color filter formed by discharging a liquid color filter material in an area surrounded by a black matrix. Light irradiating means for irradiating light from the direction inclined at a predetermined angle with respect to the surface of the filter, imaging means for imaging the surface of the color filter irradiated with light by the irradiating means, and the imaging means The imaged image information analyzing unit that analyzes the image captured by the imager to calculate the luminance difference of the color filter in each region, and the film thickness difference that estimates the film thickness difference from the luminance difference calculated by the captured image information analyzing unit And an estimation means.

  Moreover, it is preferable that a light irradiation angle is adjusted so that the said light irradiation means may irradiate the end surface close | similar to the black matrix of the said color filter.

  Furthermore, a storage means for storing reference information indicating a relationship between a preset brightness difference and a film thickness difference is provided, and the film thickness difference estimation means includes the brightness difference calculated by the captured image information analysis means, The film thickness difference may be estimated with reference to the reference information stored in the storage means.

  As described above, the film thickness difference detection apparatus according to the present invention includes a light irradiation unit that irradiates light on the film surface at a predetermined inclination angle, and an imaging unit that images the film surface irradiated with light by the light irradiation unit. And analyzing the captured image information captured by the imaging unit to calculate a luminance difference between the undulations, and each of the film surfaces from the luminance difference calculated by the captured image information analyzing unit. Even if the film thickness difference is detected on the order of several tens of nm to several hundreds of nm, the irradiation angle of the light irradiating means can be determined. It is only necessary to make adjustments, and there is an effect that the apparatus is not increased in size and the cost is not increased as in the case of using a highly coherent laser beam.

  The embodiment of the present invention will be described as follows. In the present embodiment, a color filter inspection apparatus formed by an ink jet method as a film having the fine undulations arranged in a regular order on the surface will be described. In the following description, “color filter” indicates that formed in a region corresponding to each pixel in the liquid crystal display device, and “color filter substrate” indicates that a color filter is formed on a transparent substrate such as a glass substrate. Shall be indicated.

  FIG. 2 is a schematic block diagram of the color filter inspection apparatus according to the present embodiment.

  As shown in FIG. 2, the color filter inspection apparatus inspects a color filter substrate 101 on which a color filter as an object to be inspected is formed, and irradiates light on the surface of the color filter substrate 101. Illumination device 102 as means, imaging device 103 as imaging means for imaging the surface of color filter substrate 101, movable stage 104 as a mounting table for mounting color filter substrate 101, and the entire inspection apparatus A control device 105 as control means for controlling, an image processing device 106 as image processing means for performing predetermined processing on an image picked up by the image pickup device 103, information necessary for image processing by the image processing device 106, etc. Image processing by the auxiliary recording device 107 and the image processing device 106 as storage means for recording And a result output device 108 as a result output means for outputting the results.

  That is, the color filter inspection apparatus having the above configuration irradiates the color filter substrate 101 with light, and analyzes the light (reflected light) reflected on the surface of the color filter substrate 101 to thereby form a color filter film on the color filter substrate 101. This is an apparatus for inspecting whether the color filter is a non-defective product or a defective product from the thickness difference. Therefore, an illumination device 102 as a light source that emits light and an imaging device 103 that images the surface of the color filter substrate 101 in a state where the surface is irradiated with light are provided.

  The color filter substrate 101 is placed on a movable stage 104 that can move in a uniaxial direction. Note that the inspected object such as the color filter substrate 101 that can be inspected by using the film thickness difference detection apparatus of the present invention is limited to a film-like or plate-like object regularly having fine undulations on the surface. The reason for this is that the film thickness difference detection method of the present invention is a detection method that depends on the shape of fine undulations on the surface, and the details will be apparent if the principle of the film thickness difference detection method of the present invention described later is understood in detail. It becomes.

  Further, the illumination device 102, the imaging device 103, and the movable stage 104 are based on the reference information (reference surface shape information) of the surface shape of the color filter substrate 101 stored in the auxiliary recording device 107. It is controlled by. That is, the illumination device 102 and the imaging device 103 are respectively arranged at positions where the control device 105 appropriately detects the film thickness difference of the color filter substrate 101 based on reference surface shape information of the color filter substrate 101 described later. The Further, the movable stage 104 controls the control device 105 based on the reference surface shape information so that the inspection target area on the surface of the color filter substrate 101 can be appropriately changed by moving the color filter substrate 101 by an appropriate distance. Controlled by

  The image of the surface of the color filter substrate 101 obtained through the above steps is processed by the image processing apparatus 106, and the surface shape features of the color filter substrate 101 are extracted. Based on this feature, the presence / absence of a region on the surface of the color filter substrate 101 having a shape (film thickness) that does not fall within a predetermined film thickness range is determined, and the result is output by the result output device 108.

  The image processing device 106 is also a film thickness difference detection device that detects a film thickness difference between pixels of the color filter on the color filter substrate 101. Details of the image processing apparatus 106 will be described later.

  FIG. 3 is a diagram showing a schematic configuration of a specific configuration of the film thickness difference detection apparatus in the color filter inspection apparatus.

  In the film thickness difference detection apparatus, the color filter substrate 101 is placed on the movable stage 104 as shown in FIG. The movable stage 104 can be translated in order to move the inspection position with respect to the color filter. Above the movable stage 104, a line sensor as the imaging device 103 and a light source as the illumination device 102 are arranged. A sensor for measuring light intensity is integrated in the line sensor.

  In the film thickness difference detection apparatus configured as described above, not only the movable stage 104 moves, but also the illumination device 102 moves in the same direction as the moving direction of the movable stage 104. For example, the illumination device 102 is configured to move from the first irradiation position 102a to the second irradiation position 102b. The optimum moving distance d of the illumination device 102 at this time is appropriately set based on information such as the size of the color filter substrate 101 and the required light irradiation angle included in the reference surface shape information described above. To do.

  Here, the principle of occurrence of stripe unevenness in the color filter substrate 101 will be described below with reference to FIGS.

  FIG. 4 is a schematic diagram showing the arrangement relationship of the picture elements that the surface of the color filter substrate 101 has. The color filter substrate 101 is formed by ejecting ink of three colors of red (red), green (green), and blue (blue) from a linear inkjet nozzle on a transparent substrate. . Since the transparent substrate is sequentially conveyed in a certain direction, the three color picture elements are formed in a row parallel to the substrate conveyance direction.

  The amount of ink ejected from one nozzle is substantially constant, but there may be a difference in the amount of ink ejected from each nozzle. This difference in the ink discharge amount appears as uneven stripes extending in the substrate transport direction. FIG. 4 shows a state in which streaks are generated in the substrate transport direction because a film thickness difference is generated between the blue picture element row 300 and the other picture element rows 301.

  In the film thickness difference detection apparatus of the present invention, in order to efficiently detect the stripe unevenness, the color filter substrate 101 has the stripe unevenness in the arrow Y direction (scan direction), that is, perpendicular to the moving direction of the movable stage 104. It arrange | positions on the movable stage 104 so that it may extend.

  FIG. 5 is a view showing a cross section taken along line AA of the color filter substrate 101 shown in FIG.

  As shown in FIG. 5, the light emitted from the illumination device 102 is reflected by the surface of the color filter substrate 101, and the reflected light is detected by the imaging device 103. However, if the irradiation angle of the light from the illumination device 102 is not appropriate, the reflected light from the picture element central portion 401 is too strong and the reflected light from the BM (black matrix) end surface 402 cannot be detected efficiently. .

  Therefore, in order to efficiently detect the reflected light from the BM end surface 402, it is necessary to adjust the light irradiation angle by moving the position of the illumination device 102 in parallel with the moving direction of the movable stage 104. Here, the irradiation angle refers to an angle formed by an axis extending in a direction perpendicular to the color filter substrate 101 and a path of light irradiated on the surface of the picture element.

  Therefore, FIG. 3 shows that the illumination device 102 can be irradiated from the second irradiation position 102b by being translated from the first irradiation position 102a. When the light is irradiated from the second irradiation position 102b, the irradiation angle becomes larger than when the light is irradiated from the first irradiation position 102a. As a result, the reflected light from the pixel central portion 401 is weakened, and the light from the BM end surface 402 is reduced. The reflected light can be detected more efficiently by the imaging device 103.

  In the above description, the imaging device 103 is fixed and the lighting device 102 is moved. However, the lighting device 102 may be fixed and the imaging device 103 may be moved. Further, both the illumination device 102 and the imaging device 103 may be moved.

  Here, when the illumination device 102 is translated by the optimum movement distance d and the color filter substrate 101 having a film thickness difference is imaged, an image as shown in FIG. 6 is obtained. Here, if the color filter 500 on the color filter substrate 101 has a row of picture elements having a difference in film thickness, the stripe unevenness 501 is detected.

  The optimum moving distance d, which is the distance from the first irradiation position 102a to the second irradiation position 102b of the illumination device 102, is determined depending on the surface shape of the color filter substrate 101, particularly the shape of the BM end face 402. The surface shape of the color filter substrate 101 is (1) the water-repellent condition of the black matrix, (2) the material of the ink filled in the cell, (3) the spacing of the black matrix, that is, the size of one pixel of the color filter, Depends on. Of the above (1) to (3), those other than (3) are fixed. That is, it is necessary to determine the optimum moving distance d depending on the condition (3).

  Here, an example of the procedure for determining the optimum movement distance d will be shown. This example can be applied when obtaining the reference surface shape information of the color filter substrate 101, particularly the inclination angle at the BM end face. The reference surface shape information is information used as a reference in determining the inspection conditions or determining the quality of the inspection target in the inspection of the film thickness difference in the present invention, and the non-defective product having a uniform film thickness. This is surface shape information of a reference sample obtained by analyzing the surface shape of the sample (reference sample) by an appropriate method.

  Here, FIG. 7A shows the relationship between the inclination angle of the color filter end face and the illumination shift amount, that is, the end face inclination angle of the reference sample, and the optimum moving distance d for efficiently detecting the reflected light from the BM end face. It is a graph which shows the relationship. The graph shows the distance between the illumination device 102 and the color filter substrate 101, the distance between the imaging device 103 and the color filter substrate 101, the angle between the optical axis of the imaging device 103 and the normal line of the color filter substrate 101 to the substrate. Can be created theoretically easily.

  In the graph shown in FIG. 7A, the distance between the illumination device 102 and the color filter substrate 101 and the distance between the imaging device 103 and the color filter substrate 101 are set to 600 mm and 300 mm, respectively. It is a graph when the angle between the optical axis of the imaging device 103 and the normal line of the color filter to the substrate is set to 30 degrees. Here, the moving direction of the illumination device 102 is the same as the moving direction of the movable stage 104. As described above, when the reference surface shape information of the color filter substrate 101 is obtained, the optimum moving distance d of the illumination device 102 can be determined by using the graph of FIG.

  Next, another example of the procedure for determining the optimum movement distance d will be shown. This example is effective when the reference end face information of the color filter substrate 101 cannot be obtained. FIG. 7B shows the moving distance of the illumination device 102 and the gray value of the image of the color filter substrate 101 when the position of the illumination device 102 is translated at specific intervals and the imaging of the color filter substrate 101 is repeated. It is the graph showing the relationship with. The vertical axis is the gray value of the captured image of the color filter substrate 101, and the horizontal axis is the moving distance of the illumination device 102. As shown in FIG. 7B, the light source moving distance that gives a half value of the maximum gray value is the optimum moving distance d. Thus, the optimum moving distance d can be determined without having the reference surface shape information of the color filter substrate 101.

  Next, the principle of detecting the film thickness difference of the color filter of the color filter substrate 101 will be described below with reference to FIGS. FIGS. 8A and 8B are diagrams showing the amount of reflected light on the surface of the color filter when the film thickness of a certain color filter is thinner than the film thickness of other color filters. FIGS. 9A and 9B are diagrams showing the amount of reflected light on the surface of the color filter when the film thickness of a certain color filter is thicker than the film thickness of other color filters. FIG. 10 is a graph showing the relationship between the luminance difference and the film thickness difference.

  Here, it is assumed that the color filter substrate 101 is formed by an inkjet method. In this case, the surface of the color filter also has a surface tension relationship, and the color filter (hereinafter referred to as CF) corresponding to each pixel has a shape close to a circle (ellipse). This is because the color filter material is in liquid form and this liquid material is ejected by the ink jet head.

  In the color filter substrate 101 formed as described above, the amount of ink discharged for some reason is decreased or the increased defect CF is different from the normal CF in the BM end face. This difference is an inclination angle, and in the present invention, the defect CF is detected using this difference.

  FIG. 8B shows an example of the defect CF in which the ink discharge amount is reduced and the film thickness is reduced. When the film thickness difference is small, the inclination angle is small compared to the peripheral CF. When the CF is irradiated with light at a certain angle (adjusted by shifting the position of the illumination device 102 in the present invention), reflected light does not return from the CF having a small tilt angle. Therefore, as shown in FIG. 8A, the amount of reflected light from the CF having a small film thickness is smaller than that of the peripheral CF. When this state is imaged by the imaging device 103, only the defect CF appears dark.

  In FIG. 8 (b), CF is exaggerated for easy understanding of the difference in inclination angle. Specifically, the maximum inclination angle of the BM end face is about 1 to 4 degrees. Yes, when the inclination is corrected, the inclination is about 10 to 50 μm / mm.

  The case of the defect CF having a large film thickness can be explained in the same manner as the case of the defect CF having a small film thickness.

  As the film thickness increases, the tilt angle increases compared to the peripheral CF. When the CF is irradiated with light at a certain angle as shown in FIG. 9B, reflected light is returned from the CF having a large tilt angle, but not from the peripheral CF. For this reason, as shown in FIG. 9A, the amount of reflected light from the CF having a large film thickness is larger than that of the peripheral CF. When this state is imaged by the imaging device 103, only the defect CF appears bright.

  Based on the above principle, the difference in film thickness (a value indicating whether the film thickness is larger or smaller than the reference film thickness) is the luminance difference between the captured images (the reflected light amount of the reference film thickness and the reflected light amount of the defect film thickness). (The absolute value of the difference).

  Therefore, by capturing a sample of the film thickness difference in advance and evaluating the relationship between the film thickness difference and the brightness difference of the captured image in advance, the film thickness difference of the defect CF can be determined from the captured image. Can be estimated. For example, it is conceivable to use a graph as shown in FIG. 10, that is, a graph in which the relationship between the film thickness difference and the luminance difference is evaluated in advance. If this is utilized, the film thickness difference can be easily estimated from the luminance difference obtained from the defect CF.

  Here, the surface shape information (film thickness difference and brightness) is previously obtained using a reference sample (non-defective sample), for example, using a contact-type step meter, AFM (atomic force microscope), three-dimensional measuring instrument, laser interferometer, or the like. What is necessary is just to acquire the graph which shows the relationship with a difference. This surface shape information is stored in the auxiliary recording device 107 as reference surface shape information (film thickness difference reference information), and is read out as necessary.

  In order to realize the above-described film thickness difference detection principle, the present embodiment employs an image processing apparatus 106 as shown in FIG. 1 in the color filter inspection apparatus having the above configuration.

  As shown in FIG. 1, the image processing apparatus 106 includes a captured image analysis unit 10 and a film thickness difference estimation unit 20.

  The captured image analysis unit 10 analyzes captured image information captured by the imaging device 103, and determines the luminance between the color filters from the amount of light reflected from the color filter (CF) corresponding to each pixel on the color filter substrate 101. The difference is calculated, and the calculation result is output to the film thickness difference estimation unit 20.

  The film thickness difference estimation unit 20 includes brightness difference information from the captured image analysis unit 10 and film thickness difference reference information (a graph showing the relationship between the film thickness difference and the brightness difference) stored in the auxiliary recording device 107. Thus, the film thickness difference is estimated and output to the subsequent result output device 108 as film thickness difference information.

  As a result, the output device 108 detects a color filter defect in the color filter substrate 101 from the film thickness difference information, and outputs the result.

  Hereinafter, the flow of color filter inspection processing in the color filter inspection apparatus having the above configuration will be described with reference to the flowcharts shown in FIGS. Before executing the inspection process, the surface shape of a reference sample having the same surface shape as that of the color filter substrate 101 that is the object to be inspected is previously determined using an AFM (Atomic Force Microscope), a laser interferometer, or a contact step meter. Analyze it with an appropriate measuring instrument, etc., and acquire the reference surface shape information. The acquired reference surface shape information is stored in the auxiliary recording device 107.

  First, the color filter substrate 101 that is the object to be inspected is placed on the movable stage 104 (step S1).

  Next, the control device 105 acquires reference surface shape information stored in advance from the auxiliary recording device 107 (step S2).

  Subsequently, the control device 105 determines the shift amount of the light source, that is, the optimum movement distance d of the illumination device 102 based on the acquired reference surface shape information (step S3).

  Then, under the control of the control device 105, the illumination device 102 moves by the optimum movement distance d, and the imaging device 103 images the surface of the color filter substrate 101 (step S4). Thereafter, a non-defective product determination process is performed (step S5). Details of the non-defective product determination process will be described later.

  Finally, the result of non-defective product determination is output (step S6). This result is output by the result output device 108, but it may be output so as to be displayed on a display device (not shown) for the operator of the color filter inspection device, or output to a paper medium by a printer or the like. May be.

  Subsequently, the flow of the non-defective product determination process in step S5 will be described below with reference to the flowchart shown in FIG.

  First, captured image analysis is performed (step S11). Here, the captured image analysis unit 10 in the image processing apparatus 106 performs processing for obtaining a luminance difference from the reflected light amount difference of the color filter from the input captured image information. Then, this processing result is output to the film thickness difference estimation unit 20.

  Subsequently, the film thickness difference is estimated (step S12). Here, the film thickness difference estimation unit 20 reads the film thickness difference reference information (a graph showing the relationship between the film thickness difference and the luminance difference) stored in advance in the auxiliary recording device 107, and the film thickness difference is input from the input luminance difference. The thickness difference is estimated.

  Then, it is determined whether or not the film thickness difference is equal to or less than a predetermined value D (step S13). The predetermined value D is appropriately set according to the quality required for the color filter. That is, if the quality required for the color filter is high, the value of D is set small, and if the quality required for the color filter is low, the value of D is set large.

  If the film thickness difference is equal to or smaller than the predetermined value D in step S13, it is determined that the color filter is a non-defective product (step S14). On the other hand, if the film thickness difference is larger than the predetermined value D, it is determined that the color filter is defective (step S15).

  Then, the determination results of step S14 and step S15 are returned to step S6 shown in FIG.

  As described above, in this embodiment, a film thickness difference detection device that detects a film thickness difference between color filters formed by an inkjet head method as a film having fine undulations regularly arranged on the surface is described. According to this film thickness difference detection apparatus, the difference in luminance between the color filters is detected by irradiating light at a predetermined inclination angle onto the surface of the color filter which is a fine undulation regularly arranged on the color filter substrate 101. Thus, it is possible to detect an undulating portion having a thickness different from that of other undulating portions.

  In other words, as in the present embodiment, if the film thickness difference estimation unit 20 of the image processing apparatus 106 estimates the film thickness difference between the color filters from the calculated luminance difference, it is easy with a simple configuration. It is possible to estimate the film thickness difference.

  Here, by changing the inclination angle of the light irradiated by the illumination device 102, it is possible to change the detection accuracy of the luminance difference to be detected. For example, in order to improve the detection accuracy of the luminance difference, it is preferable to irradiate light at an inclination angle that is as parallel as possible to the film surface as much as possible.

  As described above, in the present invention, it is possible to easily increase the accuracy of detecting the luminance difference by adjusting the irradiation angle of the illumination device 102. Moreover, since this illumination device 102 can use a normal light source, it can irradiate a wide range. That is, it is possible to cope with an increase in the size of the film surface to be inspected.

  Therefore, in the present embodiment, the difference in film thickness is not detected using the interference of light, so that it is not necessary to use light having a single wavelength such as laser light as in the prior art. As a result, even when the film thickness difference is detected on the order of several tens of nm to several hundreds of nm, it is only necessary to adjust the irradiation angle of the light irradiating means. As such, it does not lead to an increase in size or cost of the apparatus.

  It is preferable that the illumination device 102 has a light irradiation angle adjusted so as to irradiate light onto a curved surface having the maximum inclination angle among the curved surfaces of the color filter. As a result, the luminance difference due to the difference in the height of the color filter can be detected with high accuracy, so that it can be made more probable than the film thickness difference estimated from the luminance difference.

  In this embodiment, the film thickness difference between the color filters is obtained from the luminance difference. However, the present invention is not limited to this, and the film thickness is determined by the inclination of the color filter near the end face of the black matrix (BM). The difference may be detected to determine the color filter defect. Specifically, the determination is made from the image obtained by imaging the vicinity of the BM end face by the imaging device 103 based on the inclination (inclination angle) of the color filter in the vicinity of the BM end face. For example, in the case of a defect CF having a large film thickness difference, it can be detected that the inclination is relatively large compared to the normal CF, that is, the inclination angle is large. Further, in the case of a defect CF having a small film thickness difference, it can be detected that the inclination is relatively small compared to the normal CF, that is, the inclination angle is small.

  Thereby, it becomes possible to detect a film thickness difference with a resolution of several tens of nanometers to several hundreds of nanometers in a short time without making the inspection apparatus complicated and large.

  The color filter inspection apparatus of the present invention is a method for inspecting a color filter substrate formed using an ink jet head, and means for irradiating the color filter with illumination and means for imaging the irradiated color filter And means for obtaining reference surface shape information of each pixel element end face of the color filter, adjusting the illumination and imaging position in accordance with the reference surface shape information, and determining the end face from the image of each picture element of the color filter. The configuration may be such that information is acquired and a defect of the color filter is detected by comparison with reference information.

  As a result, the end face part of each color filter picture element in which the discharge amount between nozzles appears is adjusted by adjusting the illumination and imaging position, and the end face part is not affected by the center part of each color filter picture element. Therefore, the film thickness difference on the order of several tens nm to several hundreds nm can be detected.

  Further, the illumination unit may irradiate illumination from a direction perpendicular to a direction in which ink is ejected when creating a color filter.

  As a result, uneven stripes are generated in the ink ejection direction, and it is possible to easily detect the uneven stripes by irradiating illumination from the direction perpendicular to this direction and taking an image.

  Furthermore, only the illumination may be adjusted as a method for adjusting the illumination and the imaging position in accordance with the reference surface shape information.

  This eliminates the step of adjusting the camera lens that occurs when the camera is moved, and has the effect of preventing the apparatus from becoming large.

  As means for obtaining the reference surface shape information of each pixel element end face of the color filter described above, the reference surface shape information may be obtained by repeating imaging while moving the illumination position.

  Accordingly, there is an effect that the amount of illumination shift can be determined without obtaining the reference surface shape information of the color filter.

  The color filter inspection apparatus of the present invention is an apparatus for inspecting a color filter substrate formed using an inkjet head, and means for irradiating the color filter with illumination and means for imaging the irradiated color filter. And means for adjusting the illumination and imaging position, and means for obtaining reference surface shape information of each pixel element end face of the color filter, adjusting the illumination and imaging position according to the reference surface shape information, A configuration may be adopted in which end face information is acquired from the image of each picture element and a defect of the color filter is detected by comparison with reference information.

  In this case, a means for illuminating the color filter, a means for imaging the illuminated color filter, a means for adjusting the illumination and imaging position, and reference surface shape information of each pixel end face of the color filter are obtained. By providing the means, it is possible to image the end face portion of each picture element of the color filter, so that an effect of detecting a film thickness difference on the order of several tens of nm to several hundreds of nm is achieved.

  Further, the control device 105, the image processing device 106, and the auxiliary recording device 107 of the film thickness difference detection device of the present invention may be configured by hardware logic, or by software using a CPU as follows. It may be realized.

  That is, the control device 105 of the film thickness difference detection device, the image processing device 106, and the auxiliary recording device 107 store a CPU (central processing unit) that executes instructions of a control program that realizes each function, and the above program. A ROM (read only memory), a RAM (random access memory) for expanding the program, a storage device (recording medium) such as a memory for storing the program and various data, and the like are provided. An object of the present invention is a recording medium in which a program code (execution format program, intermediate code program, source program) of a control program for a film thickness difference detection device, which is software for realizing the functions described above, is recorded so as to be readable by a computer. Can also be achieved by reading the program code recorded on the recording medium and executing it by the computer (or CPU or MPU).

  As a storage medium for supplying the program code, for example, a floppy (registered trademark) disk, a hard disk, an optical disk, a magneto-optical disk, a magnetic tape, a nonvolatile memory card, and the like can be used.

  When the present invention is applied to the storage medium, the storage medium stores program codes corresponding to the flowcharts described above.

  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.

  The film thickness difference detection apparatus of the present invention can detect a film thickness difference on the surface of a color filter or the like created by an ink jet method with a simple configuration. It can be applied to use for detecting a film thickness difference. For example, an “organic EL (electroluminescence) light emitting layer” or “microlens” created by an inkjet method can be applied. Here, in the case of microlenses, in addition to the microlens array, the lenses are used separately in final use, and are arranged in a matrix during the formation process and inspection (for individual separation applications). Lens array). In this case, as the microlens array, various image display devices (liquid crystal, organic and inorganic EL), projectors, imaging devices, optical pickups, optical waveguides (optical fiber ends, etc.), cameras (focus plates, etc.), illumination (light For example). Further, examples of the lens array for use after individual separation include those used for various optical elements of a micro camera, various optical elements of an optical pickup, and the like. In addition, instead of the lenses of the microlens array and the lens array for individual separation, an array having a mirror provided with a reflective layer may be used.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1, showing an embodiment of the present invention, is a block diagram showing a main part configuration of a film thickness difference detection device. It is a block diagram which shows the principal part structure of the color filter inspection apparatus provided with the said film thickness difference detection apparatus. It is a figure which shows schematic structure of the specific structure of the film thickness difference detection apparatus in the said color filter inspection apparatus. It is a top view of the color filter substrate for demonstrating the state of stripe | line | muscle nonuniformity generation | occurrence | production. It is AA arrow sectional drawing of the color filter board | substrate shown in FIG. It is a figure which shows the planar picked-up image of the color filter board | substrate with which the stripe unevenness was formed. It is a graph used when determining the optimal movement distance (illumination shift amount) of an illuminating device, (a) is a graph which shows the relationship between the inclination angle of a color filter end surface, and an illumination shift amount, (b) is illumination. It is a graph which shows the relationship between a movement amount and the shading value of an image. The principle for detecting a defective color filter is shown, (a) is a graph showing the relationship between the color filter and the amount of reflected light, and (b) is a diagram showing the state of the color filter at (a). The principle for detecting a defective color filter is shown, (a) is a graph showing the relationship between the color filter and the amount of reflected light, and (b) is a diagram showing the state of the color filter at (a). It is a graph which shows the relationship between the brightness | luminance difference obtained from reference | standard surface shape information, and a film thickness difference. It is a flowchart which shows the flow of the inspection process of the color filter by the color filter inspection apparatus of the said structure. 12 is a flowchart showing a flow of non-defective product determination processing in the color filter inspection processing shown in FIG. 11.

Explanation of symbols

10 Captured Image Analysis Unit (Captured Image Analysis Unit)
20 Film thickness difference estimation unit (film thickness difference estimation means)
101 Color filter substrate (film having fine undulations regularly arranged on the surface)
102 Illumination device 103 Imaging device (imaging means)
104 movable stage 105 control device 106 image processing device (film thickness difference detection device)
107 Auxiliary recording device (storage means)
108 Result Output Device 300 Picture Element Line 301 Picture Element Line 401 Picture Element Center 402 BM End Surface 500 Color Filter 501 Streaky

Claims (13)

In a film thickness difference detection apparatus for detecting a film thickness difference between each undulation of a film having fine undulations regularly arranged on the surface,
A light irradiation means for irradiating the surface of the film with light at a predetermined inclination angle;
Imaging means for imaging the film surface irradiated with light by the light irradiation means;
Analyzing captured image information captured by the imaging unit, and calculating a luminance difference between the undulations;
A film thickness difference detecting device comprising: a film thickness difference estimating means for estimating a film thickness difference between the undulations of the film from the brightness difference calculated by the captured image information analyzing means.   2. The film thickness according to claim 1, wherein the light irradiation means has a light irradiation angle adjusted so as to irradiate light to a curved surface having a maximum inclination angle among the curved surfaces of the undulations. Difference detection device. Storage means for storing reference information indicating the relationship between the luminance difference and the film thickness difference;
The film thickness difference estimation means estimates the film thickness difference with reference to the luminance difference calculated by the captured image information analysis means and the reference information stored in the storage means. 1. The film thickness difference detection apparatus according to 1. In a film thickness difference detection device that detects a film thickness difference of a color filter formed by discharging a liquid color filter material in a region surrounded by a black matrix,
A light irradiation means for irradiating the surface of the color filter with light at a predetermined inclination angle;
Imaging means for imaging the surface of the color filter irradiated with light by the irradiation means;
A captured image information analyzing means for analyzing an image captured by the imaging means and calculating a luminance difference of the color filter in each region;
A film thickness difference detecting device comprising: a film thickness difference estimating means for estimating a film thickness difference from the luminance difference calculated by the captured image information analyzing means.   5. The film thickness difference detection device according to claim 4, wherein the light irradiation means has a light irradiation angle adjusted so as to irradiate an end face close to a black matrix of the color filter. Storage means for storing reference information indicating the relationship between the luminance difference and the film thickness difference;
The film thickness difference estimation means estimates the film thickness difference with reference to the luminance difference calculated by the captured image information analysis means and the reference information stored in the storage means. 4. The film thickness difference detection device according to 4. In the film thickness difference detection method for detecting the film thickness difference between the undulations of the film having fine undulations regularly arranged on the surface,
Irradiating the surface of the film with light at a predetermined inclination angle;
Imaging a film surface irradiated with light;
Analyzing the captured image information and calculating a luminance difference between the undulations;
And a step of estimating a film thickness difference between the undulations of the film from the calculated luminance difference. In a film thickness difference detection method for detecting a film thickness difference of a color filter formed by discharging a liquid color filter material in a region surrounded by a black matrix,
Irradiating the surface of the color filter with light at a predetermined inclination angle;
Imaging the surface of the color filter irradiated with light;
Analyzing the captured image and calculating a luminance difference of the color filter in each region;
And a step of estimating the film thickness difference from the calculated luminance difference. In a color filter inspection apparatus for inspecting a color filter formed by discharging a liquid color filter material in an area surrounded by a black matrix,
A film thickness difference detecting means for detecting a film thickness difference of the color filter between each region;
Determining means for determining whether or not the film thickness difference detected by the film thickness difference detecting means exceeds a reference range;
The film thickness difference detecting means is
Light irradiating means for irradiating light from a direction inclined at a predetermined angle with respect to the surface of the color filter;
Imaging means for imaging the surface of the color filter irradiated with light by the irradiation means;
A captured image information analyzing unit that analyzes an image captured by the imaging unit and calculates a luminance difference of the color filter in each region;
A color filter inspection apparatus comprising: a film thickness difference estimating means for estimating a film thickness difference from the brightness difference calculated by the captured image information analyzing means. In a color filter inspection method for inspecting a color filter formed by discharging a liquid color filter material in a region surrounded by a black matrix,
A first step of detecting a difference in thickness of the color filter between the regions;
A second step of determining whether or not the film thickness difference detected by the first step exceeds a reference range,
The first step is
Irradiating the surface of the color filter with light from a direction inclined at a predetermined angle with respect to the surface;
Imaging the surface of the color filter irradiated with light;
Analyzing the captured image and calculating a luminance difference of the color filter in each region;
And a step of estimating a film thickness difference from the calculated luminance difference. In a film thickness difference detection program for detecting a film thickness difference between undulations of a film having fine undulations regularly arranged on the surface,
A step of analyzing the captured image information obtained we are by imaging the surface of the film irradiated with light, calculates a luminance difference between each relief at a predetermined inclination angle,
A film thickness difference detection program for causing a computer to execute a procedure for estimating a film thickness difference between each undulation of a film from a calculated luminance difference. In a film thickness difference detection program for detecting a film thickness difference of a color filter formed by discharging a liquid color filter material in an area surrounded by a black matrix,
A step of analyzing the resulting et images by imaging the surface of the color filter where light is irradiated, and calculates the brightness difference of the color filters in each area at a predetermined inclination angle,
A film thickness difference detection program for causing a computer to execute a procedure for estimating a film thickness difference from a calculated luminance difference.   The recording medium which recorded the film thickness difference detection program in any one of Claim 11 or 12 so that computer reading was possible.

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