JP2011047681A - Inspection apparatus of mold for anti-glaring treatment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the automatic inspection apparatus of a mold capable of simultaneously detecting the presence of recessed and protruded defects on the surface of a metal mold for anti-glaring treatment having a chromium plating surface and capable of detecting a defect with high inspection precision even with respect to a plurality of kinds of molds having different surface uneven shapes. <P>SOLUTION: This inspection apparatus for detecting the recessed defect and/or protruded defect on the surface of the mold for anti-glaring treatment is equipped with a first illuminator for irradiating the surface of the mold with first light, a second illuminator for irradiating the surface of the mold with second light, a two-dimensional imaging device for acquiring the image related to the region of a part of the surface of the mold containing the regions irradiated with the first and second lights, a light intensity control means for controlling the intensities of the first and second lights and an arithmetic means for operating the difference between the brightness at the preliminarily indicated point on the image and the luminous intensity or luminous intensity range preliminarily indicated with respect to the preliminarily indicated point. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an automatic inspection apparatus for a mold used for performing an antiglare treatment of a substrate by imparting a fine uneven surface shape, and more specifically, on the surface of a metal mold for an antiglare treatment having a chrome plating surface. The present invention relates to an automatic inspection apparatus for detecting the presence or absence of a dent defect and a convex defect.

  In an image display device such as a liquid crystal display, a plasma display panel, a cathode ray tube (CRT) display, an organic electroluminescence (EL) display, and the like, when external light is reflected on the display surface, the visibility is significantly impaired. Conventionally, in order to prevent such reflection of external light, display is performed using a television or personal computer that emphasizes image quality, a video camera or digital camera that is used outdoors with strong external light, and reflected light. In a mobile phone or the like, a process for preventing external light from being reflected on the surface of the image display device is performed. The processing performed on the surface of such an image display device includes antireflection processing using interference by the optical multilayer film and prevention of blurring the reflected image by scattering incident light by forming fine irregularities on the surface. It is roughly divided into dazzling treatment. The former non-reflective treatment increases the cost because it is necessary to form a multilayer film having a uniform optical film thickness. On the other hand, since the latter anti-glare treatment can be performed relatively inexpensively, it is widely used for applications such as large personal computers and monitors.

  The antiglare treatment of the image display device is typically performed by laminating an antiglare film with antiglare properties on the surface of the image display device. Conventionally, an anti-glare film, for example, a resin solution in which fine particles are dispersed is applied on a base sheet by adjusting the film thickness, and the fine particles are exposed on the surface of the coating film so that random surface irregularities are formed on the base sheet. It is manufactured by the method of forming on top. However, the antiglare film manufactured using a resin solution in which such fine particles are dispersed has an influence on the arrangement and shape of surface irregularities depending on the dispersion state and application state of the fine particles in the resin solution. It is difficult to obtain surface irregularities as described above, and when the haze of the antiglare film is set low, there is a problem that a sufficient antiglare effect cannot be obtained. Furthermore, when such a conventional anti-glare film is disposed on the surface of the image display device, the entire display surface becomes whitish due to scattered light, and the display becomes cloudy, so-called “whiteness” is likely to occur. There was a problem. Also, with the recent high definition of image display devices, the pixels of the image display device and the surface uneven shape of the antiglare film interfere with each other, and as a result, a luminance distribution occurs and the display surface becomes difficult to see. There was also a problem that the “glare” phenomenon was likely to occur. In order to eliminate glare, there is an attempt to scatter light by providing a refractive index difference between the binder resin and the fine particles dispersed therein, but such an antiglare film is disposed on the surface of the image display device. In some cases, there is a problem that the contrast tends to be lowered due to light scattering at the interface between the fine particles and the binder resin.

  On the other hand, there is also an attempt to develop anti-glare properties using only fine irregularities formed on the surface of the transparent resin layer without containing fine particles (for example, Patent Document 1). According to this method, the antiglare property is expressed by the shape of the surface, so that no whitening due to the fine particles occurs. Furthermore, in the method of applying a resin added with fine particles, unevenness occurs due to fluctuations in the coating thickness, so precise coating thickness control has been required, but in the method of forming fine irregularities on the surface, the coating thickness Since the problem of unevenness due to fluctuation does not occur, it is possible to achieve excellent productivity.

  As a method of forming such surface irregularities, a method of transferring the irregularities of the mold onto the surface of an object (such as a transparent resin film) using a mold having a surface irregularity formed in advance is produced. It is particularly preferably used from the viewpoint of sex. However, since the surface uneven shape of the mold is transferred, if there is a defect on the uneven surface of the mold, the defect continues to occur throughout the product (such as an antiglare film). Therefore, defect detection on the uneven surface of the mold is a very important technology that affects the quality of the product.

  However, it has been difficult to realize an automatic inspection apparatus for a mold for anti-glare treatment. In the mold for anti-glare treatment, in order to prevent the generation of scratches during processing, it is necessary to apply chrome plating with high surface hardness to the surface, but when chrome plating is applied, the mold surface has a diameter of about 100 μm. In addition, a defect having a very low aspect ratio, which is a concave shape or a convex shape (projection shape) having a depth or a height of about 2 μm, frequently occurs and causes a defect that can be recognized by a person. Conventionally, however, it has been difficult to realize an apparatus capable of simultaneously detecting such a dent defect and a convex defect having a low aspect ratio, even if they occur at the same time. In addition, in the inspection apparatus that detects the presence or absence of defects on the surface of the mold for anti-glare treatment, it is possible to detect defects for a plurality of types of molds having different surface irregularities for providing different anti-glare performance. However, it has been difficult to realize an inspection apparatus that can obtain stable inspection accuracy even when inspecting dies of different varieties.

  In this way, due to the problem that it is difficult to detect peculiar defects generated on the chrome plating surface, and the problem that the inspection accuracy is not stable between molds corresponding to varieties with different anti-glare performance, At present, the automatic inspection apparatus has not been realized.

JP 2002-189106 A

  Accordingly, an object of the present invention is to simultaneously detect the presence or absence of a dent-like defect and a convex defect on the surface of a metal mold for antiglare treatment having a chrome-plated surface, and a plurality of surfaces having different surface irregularities. An object of the present invention is to provide an automatic mold inspection apparatus capable of detecting defects with high inspection accuracy even for various types of molds.

  The present invention is an inspection apparatus for detecting a dent-like defect and / or a convex defect on a surface of a mold for anti-glare treatment, and a first light for irradiating the mold surface with a first light. An image of a part of the mold surface including illumination, a second illumination for irradiating the mold surface with the second light, and a region irradiated with the first light and the second light , A light intensity control means for controlling the intensity of the first light and the second light, and lightness at a predesignated point on an image obtained by the two-dimensional imaging device And a calculation means for calculating a difference between the previously specified point and a previously specified brightness or a previously specified brightness range.

  In the two-dimensional imaging device, the first illumination, and the second illumination, in an image obtained by the two-dimensional imaging device, the first bright portion caused by the first light scattering and the second light scattering A second bright part due to the light, and a dark part that is located between the first bright part and the second bright part and has a lightness lower than that of the first bright part and the second bright part. It is preferable to arrange | position.

  In the inspection apparatus of the present invention, based on the calculation result of the calculation means, the light intensity control means determines whether the lightness at a predesignated point on the image is the predesignated lightness or the predesignated lightness. It is preferable that the intensity of the first light and / or the second light is controlled so as to fall within the range of.

  The predesignated points on the image preferably include at least one point in the first bright part and at least one point in the second bright part.

  In the inspection apparatus of the present invention, it is preferable that the intensity of the first light is controlled by the light intensity control means so that the first bright portion shows the maximum brightness in the image.

  In the inspection apparatus of the present invention, preferably, by detecting the presence or absence of a bright spot in the dark side end region of the first bright portion and / or the presence or absence of a dark spot in the second bright portion, The presence or absence of a dent and / or convex defect on the mold surface is detected.

A straight line passing through the center point T passing through the center point T of the region corresponding to the dark part on the mold surface and parallel to the optical axis of the two-dimensional imaging device is defined as a straight line M, and the straight line passing through the center point T formed by the straight line M is 2α. When the straight line N is used (here, α [°] is an angle formed by the normal of the surface averaged over the region irradiated with the first light on the mold surface and the straight line M). Is arranged so as to satisfy the following formula (1) when arranged within the region R defined by the straight line M and the straight line N, and satisfy the following formula (2) when arranged outside the region R. It is preferable.
θ _E1 ≦ 2α-2x (1)
θ _E1 ≧ 2α + 2x (2)
Here, in the equation, θ _E1 [°] is an angle formed by the straight line M and a straight line connecting the point L _E1 on the end of the straight line N and the center point T in the first illumination, and x [°]. Is the minimum value of the maximum inclination angle of each of the dent defects that can exist on the mold surface, that the defect to be detected has.

Further, a straight line passing through the center point T ′ of the region corresponding to the second bright portion on the mold surface and parallel to the optical axis of the two-dimensional imaging device is defined as a straight line M ′, and an angle formed with the straight line M ′ is 2α ′. When a straight line passing through the center point T ′ is a straight line N ′ (where α ′ [°] is the normal of the surface averaged over the region irradiated with the second light on the mold surface) And the second illumination is preferably arranged on the straight line N ′ so as to satisfy the following formulas (3) and (4).
θ ′ _E1 > 2α′−2x ′ (3)
θ ′ _E2 <2α ′ + 2x ′ (4)
Here, in the equation, θ ′ _E1 [°] is an angle formed by the straight line M ′ and a straight line connecting the point L ′ _E1 on the end of the straight line M ′ side and the center point T ′ in the second illumination. , Θ ′ _E2 [°] is an angle formed by the straight line M ′ and a straight line connecting the point L ′ _E2 on the end opposite to the straight line M ′ side in the second illumination and the center point T ′. , X ′ [°] is the minimum value of the maximum inclination angle of each of the convex defects that can exist on the mold surface, that the defect to be detected has.

  The inspection apparatus of the present invention preferably further includes a moving means for moving the position of the region irradiated with the first light and the second light on the mold surface. The moving means preferably includes means for moving the two-dimensional imaging device, the first illumination, and the second illumination with respect to the mold while maintaining a relative positional relationship with each other.

  The inspection apparatus of the present invention preferably further includes image processing means for performing shading correction on an image obtained by the two-dimensional imaging device.

  According to the inspection apparatus of the present invention, it is possible to detect the presence or absence of a dent defect and / or a convex defect on the surface of a metal mold for antiglare treatment having a chrome plating surface. Even if both occur, these defects can be detected simultaneously. In addition, it is possible to detect defects stably with high inspection accuracy even for a plurality of types of dies having different surface irregularities.

It is a schematic perspective view which shows a preferable example of the test | inspection apparatus of this invention. It is a block diagram which shows a preferable example of a structure of the test | inspection apparatus of this invention. It is a schematic diagram for demonstrating the image obtained by a two-dimensional imaging device. It is a figure which shows an example of the image data obtained using the test | inspection apparatus of this invention. It is a flowchart which shows the method of controlling the intensity | strength of 1st light and / or 2nd light. It is a figure for demonstrating the point (coordinate) by which the brightness on image data is designated beforehand. It is a schematic diagram for demonstrating arrangement | positioning of the 1st illumination in the inspection apparatus of this invention. It is a schematic diagram for demonstrating the reflection direction of the light in a dent-like defect. It is a schematic diagram for demonstrating arrangement | positioning of the 2nd illumination in the test | inspection apparatus of this invention. It is a schematic diagram for demonstrating the reflection direction of the light in a convex defect. It is a figure which shows typically a preferable example of the first half part of the manufacturing method of the anti-glare process metal mold | die suitable as a test object. It is a figure which shows typically a preferable example of the second half part of the manufacturing method of the anti-glare process metal mold | die suitable as a test object. It is a figure which shows typically the state which side etching advances in a 1st etching process. It is a figure which shows typically the state where the uneven surface formed by the 1st etching process dulls by the 2nd etching process. 1 is a diagram schematically illustrating an inspection apparatus manufactured in Example 1. FIG.

<Inspection device>
FIG. 1 is a schematic perspective view showing a preferred example of the inspection apparatus of the present invention, and FIG. 2 is a block diagram showing a preferred example of the configuration of the inspection apparatus of the present invention. The inspection apparatus of the present invention is an apparatus for detecting a concave defect and / or a convex defect on the surface of an antiglare treatment mold, and as shown in FIGS. The surface of 201 was irradiated with the first illumination 102 for irradiating the first light, the second illumination 103 for irradiating the second light, and the first light and the second light. A two-dimensional imaging device 101 for acquiring an image of a partial region of the mold surface including the region, a light intensity control means 106 for controlling the intensity of the first light and the second light, and 2 Computing means 107 for computing the difference between the brightness at a predesignated point on the image obtained by the three-dimensional imaging device and the predesignated brightness or a predesignated brightness range for the predesignated point; At least. Hereinafter, the mold inspection apparatus of the present invention will be described in more detail.

(First illumination and second illumination)
The inspection apparatus of the present invention includes at least two lights of a first light 102 and a second light 103. The first illumination 102 is for irradiating the surface of the anti-glare processing mold 201 to be inspected with the first light, and the second illumination 103 is applied to the surface of the mold 201 on the second surface. It is for irradiating the light. By using two different illuminations, it is possible to detect both dent and convex defects that may be present on the surface of the mold 201. That is, the first illumination 102 is illumination for detecting a dent defect, and the second illumination 103 is illumination for detecting a convex defect.

  As the first illumination 102 and the second illumination 103, various illuminations such as an incandescent lamp, a fluorescent lamp, and a light emitting diode (LED) can be used. Among these, the LED illumination is intensity control and brightness stability. It is preferably used from the aspect of. A straight tube fluorescent lamp is preferable because it is inexpensive. Examples of the shapes of the first illumination 102 and the second illumination 103 include various shapes such as a ring shape, a flat panel shape, and a line shape. If the surface is a side surface of a cylindrical mold (roll mold) or a surface of a flat mold, bar illumination as the first illumination 102, as shown in FIG. It is preferable to use linear (linear) illumination such as a cold cathode tube or a straight tube fluorescent lamp, and it is preferable to use flat panel illumination as the second illumination 103.

(Light intensity control means)
The inspection apparatus of the present invention includes a light intensity control means 106 connected to the first illumination 102 and the second illumination 103 for controlling the intensity of the first light and the second light. When LED illumination is used as the first illumination 102 and the second illumination 103, the light intensity control means 106 for controlling the emission intensity has a sufficiently high oscillation frequency with respect to the exposure time of a two-dimensional imaging device described later. Pulse width modulation (PWM) means can be preferably used. Commercially available products can be used as such pulse width modulation means, for example, CA-DC100, CA-DC20E (manufactured by Keyence Corporation), PC-2 (manufactured by Kondo Seisakusho Co., Ltd.) sold by Keyence Corporation. Etc. Further, in the case of an incandescent lamp, a slidac or variable resistor can be used as the light intensity control means 106, and in the case of a fluorescent lamp, an inverter that changes the input voltage can be used.

(2D imaging device)
The inspection apparatus of the present invention includes a two-dimensional imaging device 101 for acquiring an image of a partial region on the surface of a mold 201 including a region irradiated with first light and second light. In the present invention, based on the image obtained by the two-dimensional imaging device 101, the presence or absence of a dent defect and / or a convex defect on the surface of the mold 201 is detected.

  As the two-dimensional imaging device 101, various types of imaging devices such as a CCD system and a CMOS system can be used. As a CCD type two-dimensional imaging device, for example, CV-H500C, CV-H500M, CV-H200C, CV-H200M, CV-H100C, CV-H100M (above, manufactured by Keyence Corporation), and FZ-SC5M, Examples thereof include FZ-S5M, FZ-SC2M, and FZ-S2M (manufactured by OMRON Corporation).

  In the present invention, the two-dimensional imaging device 101 has a higher imaging resolution because it can detect finer defects and can inspect the mold surface over a wider range in the case of the same resolution capability. It is preferable to use one. For example, in the case of the two-dimensional CCD imaging device manufactured by Keyence Corporation exemplified above, CV-H200C is more preferable than CV-H100C, and CV-H500C is more preferable than CV-H200C. There are two types of CCD imaging devices, color and black and white, but any of them can be preferably used in the mold inspection apparatus of the present invention.

  In the above-described commercially available two-dimensional imaging devices, it is common that various lenses can be selected from the focal length, magnification, and the like. For example, as a lens sold by Keyence Corporation, the CA-LH series (focal length 8 mm, 16 mm, 25 mm, 50 mm) and the CA-LM series (telecentric magnification x0.5 to x) employing a telecentric optical system. 1.0, x2, x4, x6, x8). A lens employing a telecentric optical system has an advantage that the size of an image obtained by a two-dimensional device does not depend on the distance between the two-dimensional imaging device and a mold to be inspected. Any lens system may be used in the inspection apparatus of the present invention, but it is preferable to use a normal lens that does not employ a telecentric optical system because of its high efficiency of capturing light. When a lens having high efficiency for capturing light is used, it is possible to increase the shutter speed, thereby enabling high-speed imaging and reducing image blurring.

  In the inspection apparatus of the present invention, it is preferable that the focal length of the lens is long. This is because the angle range of the light to be taken in can be narrowed when the focal length is longer, and it becomes easier to detect light scattering due to the defect. A preferable focal length is 25 mm or more, and more preferably 50 mm or more. When the focal length is short, the light scattered in an angular range different from the normal due to the defect is also taken in by the lens system and reaches the two-dimensional imaging device, so that the defect detection ability tends to be lowered. In addition, it is preferable that the aperture of the lens when using the inspection apparatus is small. This is because the effect of narrowing the angle range of the light to be captured can be expected by reducing the aperture.

(Calculation means)
The inspection apparatus of the present invention provides a difference between the lightness at a predesignated point on the image obtained by the two-dimensional imaging device 101 and the predesignated lightness or a predesignated lightness range for the predesignated point. The calculation means 107 for calculating is provided. Examples of the computing means 107 include a general purpose computer such as a personal computer (more specifically, a central processing unit (CPU)), a programmable logic controller (PLC), and the like. As a general-purpose computer that can be used for the computing means 107, for example, an inexpensive personal computer equipped with Windows XP Pro as basic software (OS) can be used. The model is not particularly limited, but has a function for communicating with other devices such as Ethernet and RS232C (serial port) (specific examples include, for example, Vostro220 sold by Dell Corporation) ) Is preferred.

  Further, the inspection apparatus of the present invention normally has a point (coordinates) specified in advance on the image on which the brightness difference is compared and information on the previously specified brightness at that point or the range of brightness specified in advance. In addition, storage means 110 for storing image data of an image obtained from the two-dimensional imaging device 101 is provided. When a general-purpose computer such as a personal computer is used as the computing means 107, the storage device of the general-purpose computer can be used as the storage means 110. The difference between the lightness (or lightness range) designated in advance at a specific point (coordinate) on the image stored in the storage unit 110 and the lightness at the specific point in the image data of the image obtained from the two-dimensional imaging device 101. Is computed by the computing means 107. Note that a general-purpose computer such as a personal computer as the computing means 107 and the storage means 110 can include a light intensity control means 106 and a control means 111 for controlling a motor controller 112 described later.

(Image processing means)
The inspection apparatus of the present invention preferably includes an image processing means 108 for converting an image obtained from the two-dimensional imaging device 101 into image data and transferring the image data to the storage means 110. However, the computing unit 107 and the personal computer or the like as the storage unit 110 themselves may have a function as the image processing unit.

  The image processing means 108 is connected to the two-dimensional imaging device 101 directly or via a camera controller 109 for converting or processing a signal sent from the two-dimensional imaging device 101 (see FIG. 2). It is also preferable to use a camera controller integrated image processing system such as CV-5700 (manufactured by Keyence Corporation) as the image processing means 108 and camera controller 109. The CV-5700 has a function of transferring an image obtained by the two-dimensional imaging device 101 as bitmap format image data via Ethernet to the storage unit 110 such as a personal computer. By connecting the personal computer and the CV-5700 via Ethernet, the image of the two-dimensional imaging device can be transferred to the personal computer or the like as image data.

  The image processing unit 108 may have a function of performing various filter processes on image data of an image obtained by the two-dimensional imaging device 101. By performing such image filter processing, it is possible to reduce noise, enhance brightness change, or correct uneven illumination state. Examples of the filter include a shading correction filter, a contrast correction filter, a brightness correction filter, an intermediate value filter (also called a median filter), and a blur filter. Each filtering process can be achieved by various known algorithms.

  As described above, the image processing means 108 having such a filter processing function may be a separate device from the personal computer or the like as the computing means 107 and the storage means 110, or the personal computer or the like itself. There may be. In the former case, when requesting the processing speed of the image filter processing, an image processing system equipped with a dedicated digital signal processor (DSP) may be used as the image processing means 108. As an apparatus for mounting an image processing system mounted with a DSP, for example, CV-5000 series, CV-3000 series manufactured by Keyence Corporation, ZFX series, FZ3 series manufactured by OMRON Corporation, and the like are available. In the latter case, a large-capacity main storage device or a device called a workstation equipped with a plurality of CPUs may be used.

  Among the filter processes, the inspection apparatus of the present invention preferably has a shading correction function because it can stably detect the presence or absence of defects. The shading correction means correcting a background lightness change of image data that may be caused by the illumination state of the mold 201 to be inspected or the sensitivity non-uniformity of the two-dimensional imaging device 101. For example, when brightness unevenness occurs such that the peripheral portion of the image data is darker than the central portion, the entire image data is corrected so as to have an average uniform brightness by shading correction.

  Various algorithms for shading correction have been proposed, but the most general method is to extract a change in the brightness of the background due to the illumination state or the like from the obtained image data, and correct based on this. As a method for extracting the change in brightness of the background, there is a method for estimating the change in brightness of the background by removing fine fluctuations in brightness by applying, for example, a blur filter or an intermediate value filter to the obtained image data.

  The shading correction can be performed by using an image processing system equipped with a shading correction function as the image processing means 108 or using a personal computer or the like equipped with image processing software. As an image processing system having a shading correction function, CV-5700 (manufactured by Keyence Corporation) equipped with a real-time shading correction function, and an image processor unit PSM-3310-01AD14 (Aval Data Co., Ltd.) equipped with a dynamic shading correction function. Manufactured).

(transportation)
The inspection apparatus of the present invention preferably further includes a moving means for moving the position on the surface of the mold 201 in the region irradiated with the first light and the second light. This makes it possible to inspect the entire surface of the fine irregularities of the mold to be inspected sequentially or continuously. The moving means is a first moving means 104 that moves the two-dimensional imaging device 101, the first illumination 102, and the second illumination 103 with respect to the mold 201 while maintaining the relative positional relationship with each other. It may be the second moving means 105 that moves or rotates the mold 201 itself to be inspected, or may have both of them.

  Examples of the first moving means 104 include a linear actuator that is a linear motion mechanism, and a combination of this with a stepping motor, a servo motor, a DC motor, or the like (for example, a servo linear actuator). In the example shown in FIG. 1, a servo linear actuator is used as the first moving means 104, and the servo linear actuator is a base that holds the two-dimensional imaging device 101, the first illumination 102, and the second illumination 103. Holding. Therefore, when the servo linear actuator moves, the two-dimensional imaging device 101, the first illumination 102, and the second illumination 103 for each base held by the servo linear actuator are moved relative to the mold 201 without changing the relative positional relationship. The As described above, the first moving unit 104 that can move the two-dimensional imaging device 101, the first illumination 102, and the second illumination 103 as one unit while fixing the relative positional relationship thereof is provided. As a result, the inspection can be performed over the entire surface of the fine irregularities of the mold while maintaining the inspection conditions constant.

  As the second moving means 105, various driving means such as a stepping motor, a servo motor, and a DC motor can be used. In particular, a stepping motor can be preferably used from the viewpoint of controllability of the movement amount. Various gears can be further combined depending on the accuracy and torque required. Examples of stepping motors include AS series and AR series, and examples of servo motors include NX series (both manufactured by Oriental Motor Co., Ltd.), and products in combination with gears can be obtained. Examples of the linear actuator include ESR series, EZSII series, and EZX series (all manufactured by Oriental Motor Co., Ltd.). These motors are general-purpose products, and similar products can be obtained from various companies.

  The first and second moving means 104 and 105 are usually connected to a motor controller 112 (for example, a motor controller EMP400 manufactured by Oriental Motor Co., Ltd.) that controls these drivings, and the motor controller 112 is a control means that controls this. 111 is connected. The control means 111 normally controls the light intensity control means 106 together with the motor controller 112.

<Defect detection using inspection equipment>
Next, a method for detecting a dent defect and / or a convex defect on the surface of the mold for anti-glare treatment using the inspection apparatus of the present invention will be described. Also, preferable arrangement conditions and the like of the first illumination 102 and the second illumination 103 in the inspection apparatus will be described together.

  First, the first light 102 and the second light 103 are respectively applied to the surface of the anti-glare processing mold 201 to be inspected (the surface having a fine uneven shape to be transferred) from the first light 102 and the second light 103. The two-dimensional imaging device 101 acquires an image of a partial region of the mold surface including the region irradiated with the first light and the second light. As described above, the acquired image is converted into image data by the image processing unit 108 and the like, and is subjected to filter processing such as shading correction as necessary and stored in the storage unit 110.

  For example, a case where CV-5700 (manufactured by Keyence Corporation) is used as the image processing means 108 and camera controller 109 and a personal computer connected to the CV-5700 by Ethernet is used as the computing means 107, the storage means 110, and the control means 111 is used. As an example, an image acquired by the two-dimensional imaging device 101 is converted into image data in a bitmap format by CV-5700 and stored in the storage unit 111 of the personal computer. In this case, the output format of CV-5700 is a 24-bit color bitmap format, and the image data can be stored in the storage unit 111 as it is as a 24-bit color bitmap format without conversion. In the 24-bit color bitmap format, a total of 24 bits of information is recorded as one pixel, with 8 bits assigned to each of the three primary colors red, green, and blue, following the header portion that records the width and height of the image. Yes. This bitmap image is stored in the storage area of the storage means 110 that is continuously secured corresponding to the bitmap image.

  Here, in the present invention, by appropriately adjusting the relative positions of the two-dimensional imaging device 101, the first illumination 102, and the second illumination 103 in the inspection apparatus, as shown in FIG. In the image (image data) 300 obtained by the three-dimensional imaging device 101, the first bright portion 301 caused by the scattering of the first light irradiated by the first illumination 102 and the second illumination 103 are irradiated. The first bright portion 301 and the second bright portion 302 are located between the second bright portion 302 due to the second light scattering, and between the first bright portion 301 and the second bright portion 302. A dark portion 303 having a lower brightness is generated.

  In the present invention, the image data having the first bright portion 301, the second bright portion 302 and the dark portion as described above is acquired, and the dent-like defect and / or convexity on the mold surface is obtained based on the image data. A defect is detected. That is, with reference to FIG. 3, the presence or absence of a dent-like defect is detected in the first inspection region 310 which is the end region on the dark portion 303 side in the first bright portion 301 to which the first illumination 102 gives the brightness. The presence or absence of a convex defect is detected in the second bright portion 302 where the second illumination 103 gives lightness, particularly in the second inspection region 320 which is the central region. The first inspection area 310 is an area having a lightness lower than that of the central area of the first bright portion 301. By checking the presence or absence of a bright point existing in the first inspection area 310, the first inspection area 310 has a concave shape. The presence or absence of defects can be determined. This bright point is due to the fact that a part of the first light is scattered in the direction of the two-dimensional imaging device 101 due to the concave defect. Further, by confirming the presence or absence of dark spots existing in the second inspection region 320, the presence or absence of convex defects can be determined. This dark spot is caused by a part of the second light being scattered in a direction other than the two-dimensional imaging device 101 by the convex defect.

  FIG. 4 is a diagram showing an example of image data obtained using the inspection apparatus of the present invention. In the example shown in FIG. 4, a bright spot corresponding to a dent defect exists in an area corresponding to the first inspection area 310.

  In acquiring the image data, in order to be able to detect both the dent defect and the convex defect with higher accuracy, and higher inspection for a plurality of types of dies having different surface irregularities. In order to make it possible to detect defects more accurately and stably, the intensity of the first light and / or the second light is appropriately set by the light intensity control means 106 so as to satisfy the following conditions. It is preferable to control.

  That is, the intensity of the first light and / or the second light is such that the lightness at a point (coordinates) designated in advance on the image obtained by the two-dimensional imaging device 101 is the lightness (or lightness) designated in advance for that point (or It is preferably controlled so as to be within the brightness range. Control of the intensity of the first light and / or the second light for satisfying such a condition can be performed according to the flowchart shown in FIG. That is, first, brightness information at a point (coordinate) designated in advance on the image data stored in the storage unit 110 is acquired from the image data stored in the storage unit 110. Next, the difference between the lightness of the image data at the point (coordinates) and the lightness (or lightness range) preliminarily designated for the predesignated point (coordinates) stored in the storage unit 110 by the arithmetic means 107. Is calculated to determine whether the brightness of the image data at the point (coordinates) is the brightness specified in advance (or within the brightness range). As a result of the determination, if all the designated points have the designated brightness (or within the brightness range), the illumination intensity is set to the current value. In other cases, the light intensity control means 106 changes the intensity of illumination that gives lightness to a designated point that is not designated lightness (or within a lightness range). The width for changing the illumination intensity is determined by the difference between the target brightness and the current brightness.

  By controlling the intensity of the first light and / or the second light so as to satisfy the above conditions, the inspection accuracy of the anti-glare mold can be stabilized.

  In order to obtain brightness information of a point (coordinate) designated in advance in the image data, the address of the corresponding storage means 110 is obtained by calculation based on the width / height information of the bitmap image, and by calculation. What is necessary is just to read the information stored in the obtained address. At this time, information corresponding to the three primary colors of red, green, and blue may be read out independently, or an average of red, green, and blue values may be adopted as the brightness. In addition, information corresponding to any color may be selected as lightness information depending on the illumination system. For example, when red LED illumination is used, only the red value may be used as the brightness information. Furthermore, the pixel from which the brightness information is acquired may be one pixel or an average of a plurality of pixels. By obtaining the average of a plurality of pixels, it is preferable because a more stable inspection result can be obtained.

  The “pre-designated point (coordinates) on the image data” preferably includes at least one point in the first bright portion 301 and at least one point in the second bright portion 302. . FIG. 6 is a diagram for explaining points (coordinates) for which brightness on image data is designated in advance. In FIG. 6, “brightness designation coordinate 1” near the center of the first bright portion 301 is selected as the designated point (coordinates) in the first bright portion 301, and the designated point (coordinates) in the second bright portion 302 is selected. ) Shows an example in which “brightness designation coordinate 3” near the center of the second bright portion 302 is selected. As described above, the lightness at at least one point in the first light portion 301 and at least one point in the second light portion 302 is set to a lightness (or lightness range) designated in advance. By controlling the intensity of illumination, the brightness of the first inspection area 310 and the second inspection area 320, which are areas for detecting the presence or absence of defects, can be easily determined as to the presence or absence of corresponding bright and dark spots. Can be lightness.

  Here, as described above, the detection of the dent-like defect in the first inspection region 310 is determined based on the presence or absence of a bright spot in the region. Therefore, in order to detect the concave defect more reliably and accurately, it is preferable to increase the intensity of the scattered light in the direction of the two-dimensional imaging device of the first light scattered by the concave defect as much as possible. It is preferable to control the intensity of the first light so that the first light portion 301 exhibits the maximum lightness on the image. This means that the lightness designated in advance for the designated point (coordinates) in the first light portion 301 is set larger than the designated lightness of any other designated point. For example, in the example of FIG. 6, the illumination intensity is controlled so that the brightness of “brightness designation coordinate 1” is larger than any other brightness designation point.

  On the other hand, in the first inspection region 310, the intensity of scattered light in the direction of the two-dimensional imaging device is made relatively small in order to detect the bright spot corresponding to the dent defect more accurately and accurately. It is advantageous to increase the brightness difference. From this point of view, at least the first inspection region 310 (that is, the end region on the dark portion 303 side in the first bright portion 301) is used as the above-mentioned “predetermined point (coordinates) on the image data”. One point is further designated (for example, “brightness designation coordinate 2” in FIG. 6), and the designated brightness of the brightness designated point in the first inspection region 310 is designated as the designated brightness of the designated point in the first light portion 301. It is preferable to set a smaller value.

  Further, as described above, the detection of the convex defect in the second inspection region 320 is determined based on the presence or absence of a dark spot in the region. Therefore, in order to detect the convex defect more reliably and accurately, the intensity of the scattered light in the direction of the two-dimensional imaging device is relatively increased in the second bright portion 302 (and hence the second inspection region 320). It is advantageous to increase the brightness difference with respect to the dark spot. From such a viewpoint, it is preferable to control the intensity of the second light so that the second bright portion 302 exhibits a certain brightness. This means that a certain brightness is set for the designated point (coordinates) in the second bright portion 302.

  However, it is preferable that the designated brightness of the designated point in the second bright portion 302 is set smaller than the designated brightness of the designated point in the first bright portion 301. This is caused by a defect in which the two-dimensional imaging device 101 is saturated by strong light from the first and second illuminations 102 and 103 when the intensity of illumination is set so that the second light portion 302 exhibits the maximum lightness. This is because it becomes difficult to detect bright and dark spots.

  In the inspection apparatus of the present invention, in order to be able to detect a dent-like defect as a bright point existing in the first inspection region 310 that is the end region of the first bright portion 301 on the dark portion 303 side, The first light scattered by the defect needs to travel in the direction of the two-dimensional imaging device. For this purpose, it is preferable that the 1st illumination 102 is arrange | positioned so that following formula (1) or (2) may be satisfy | filled.

More specifically, referring to FIGS. 7 and 8, a straight line M passing through the center point T of the region corresponding to the dark portion 303 on the surface of the mold 201 and parallel to the optical axis of the two-dimensional imaging device 101 is defined as a straight line M. A straight line passing through the center point T having an angle of 2α [°] with the straight line M is defined as a straight line N. Here, with reference to FIG. 8, α [°] is an angle formed by the normal line of the surface Y that averages the area irradiated with the first light on the surface of the mold 201 and the straight line M, and α < Satisfies 90 °. At this time, when the first illumination 102 is arranged in the region R defined by the straight line M and the straight line N, the first illumination 102 is expressed by the following formula (1):
θ _E1 ≦ 2α-2x (1)
It is preferable to satisfy.

In the above equation (1), θ _E1 [°] is an angle formed by the straight line M and the straight line Q connecting the point L _E1 on the straight line N side end portion of the first illumination 102 and the center point T. x [°] is the minimum value of the defect having the defect to be detected among the maximum inclination angles of the respective concave defects A that can exist on the surface of the mold 201.

As shown in FIG. 8A, the angle formed by the incident direction of the first light irradiated on the slope of the dent defect A and the emission direction of the light reflected by the slope of the dent defect A is 2α-2x. Therefore, the first light scattered by the inclined surface having the maximum inclination angle x of the concave defect A is directed toward the two-dimensional imaging device, and a bright point corresponding to the concave defect is observed in the first inspection region 310. In order to achieve this, it is preferable that θ _E1 be 2α−2x or less.

On the other hand, when the 1st illumination 102 is arrange | positioned outside the area | region R prescribed | regulated by the straight line M and the straight line N, the 1st illumination 102 is following formula (2):
θ _E1 ≧ 2α + 2x (2)
It is preferable to satisfy. In the above formula (2), θ _E1 , α, and x have the same meaning as described above. In the case where the first illumination 102 is disposed outside the region R defined by the straight line M and the straight line N, α + 2x is 90 ° or less.

As shown in FIG. 8B, in the case where the first illumination 102 is disposed outside the region R, the incident direction of the first light applied to the slope of the concave defect A and the concave defect The angle formed by the emission direction of the light reflected by the slope of A is 2α + 2x. Therefore, when the first illumination 102 is disposed outside the region R, the first light scattered by the inclined surface having the maximum inclination angle x of the concave defect A is directed toward the two-dimensional imaging device, and the first inspection is performed. In order to observe a bright point corresponding to the dent defect in the region 310, it is preferable to set θ _E1 to 2α + 2x or more.

  In the inspection apparatus of the present invention, in order to be able to detect a convex defect as a dark spot existing in the second inspection region 320 in the second bright portion 302, the second scattered by the convex defect. The second light needs to travel in a direction other than the direction of the two-dimensional imaging device. For this purpose, the second illumination 103 is preferably arranged so as to satisfy the following formulas (3) and (4).

More specifically, referring to FIG. 9 and FIG. 10, a straight line passing through the center point T ′ of the region corresponding to the second bright portion 302 on the surface of the mold 201 and parallel to the optical axis of the two-dimensional imaging device. Is a straight line M ′, and a straight line passing through a center point T ′ having an angle of 2α ′ with the straight line M ′ is a straight line N ′. Here, α ′ [°] is an angle formed by the normal line of the surface Y ′ and the straight line M ′ that averages the area irradiated with the second light on the surface of the mold 201 with reference to FIG. , Α ′ <90 ° is satisfied. At this time, the second illumination 103 is placed on the straight line N ′ by the following equations (3) and (4):
θ ′ _E1 > 2α′−2x ′ (3)
θ ′ _E2 <2α ′ + 2x ′ (4)
It is preferable to arrange so as to satisfy. Α ′ + 2x ′ is 90 ° or less.

In the above formula, θ ′ _E1 [°] is an angle formed by the straight line M ′ and a straight line Q ′ connecting the point L ′ _E1 on the straight line M ′ side end portion of the second illumination 103 and the center point T ′. Yes, θ ′ _E2 [°] is a straight line M ′ and a straight line S ′ that connects the point L ′ _E2 and the center point T ′ on the end opposite to the straight line M ′ side in the second illumination 103. It is an angle to make. x ′ [°] is the minimum value of the maximum inclination angle of each of the convex defects B that can exist on the surface of the mold 201, which the defect to be detected has.

As shown in FIG. 10 (a), with respect to the second light emitted from the end portion of the second illumination 103 on the straight line M ′ side, the incident direction of the second light applied to the slope of the convex defect B and The angle formed by the emission direction of the light reflected by the slope of the convex defect B is 2α′−2x ′. Therefore, the second light scattered by the inclined surface having the maximum inclination angle x of the convex defect B does not reach the two-dimensional imaging device by traveling in a direction other than the two-dimensional imaging device direction, and the second inspection region 320 In order to observe a dark spot corresponding to a convex defect, it is preferable to make θ ′ _E1 larger than 2α′−2x ′. Further, the second light emitted from the end of the second illumination 103 opposite to the straight line M ′ side is irradiated to the slope of the convex defect B as shown in FIG. The angle formed between the incident direction of the second light and the emitting direction of the light reflected by the inclined surface of the convex defect B is 2α ′ + 2x ′. Accordingly, the second light scattered by the inclined surface having the maximum inclination angle x of the convex defect B does not reach the two-dimensional imaging device by going in a direction other than the two-dimensional imaging device direction, and the second inspection region 320 In order to observe a dark spot corresponding to a convex defect, it is preferable to make θ ′ _E2 smaller than 2α ′ + 2x ′.

  By adjusting the relative arrangement with respect to the two-dimensional imaging device, the size (width, etc.) of the illumination, etc., the first illumination 102 and the second illumination 103 satisfying the above formula can be obtained. The size of the illumination may be adjusted by shielding a part of the light emitting unit with an attached light shielding plate. According to the study of the present inventor, when the maximum inclination angles x and x ′ of the dent defect and the convex defect generated on the surface of the metal mold for anti-glare treatment having the chrome plating surface are 4 ° or more, the dent is obtained. The dent defect and the convex defect are defects that can be recognized by humans. Therefore, in the above formulas (1) to (4), by substituting numerical values of 4 ° or less as x and x ′, all defects that can be recognized by humans can be detected by the inspection apparatus of the present invention. .

  After inspecting the presence or absence of a dent-like defect and / or a convex defect on a part of the fine uneven surface of the mold 201 by the above procedure, the moving means (the first moving means 104 and / or the first By changing the inspection position using the second moving means 105), the same inspection is performed on the fine uneven surface of other portions.

<Anti-glare mold for inspection>
The inspection apparatus of the present invention can be preferably used for defect inspection of anti-glare processing molds manufactured as follows, for example.

  FIG. 11 is a diagram schematically showing a preferred example of the first half of the method for manufacturing a mold for anti-glare treatment suitable as an inspection object. In FIG. 11, the cross section of the metal mold | die in each process is shown typically. The mold manufacturing method includes: [1] a first plating step, [2] a polishing step, [3] a photosensitive resin film forming step, [4] an exposure step, [5] a developing step, [ 6) Basically includes a first etching step, [7] photosensitive resin film peeling step, and [8] second plating step.

[1] First plating step In this step, first, copper plating or nickel plating is applied to the surface of the base material used in the mold. Thus, by performing copper plating or nickel plating on the surface of the mold base, it is possible to improve the adhesion and gloss of chromium plating in the subsequent second plating step.

  The copper or nickel used in the first plating step may be a pure metal, or may be an alloy mainly composed of copper or an alloy mainly composed of nickel. “Copper” means to include copper and copper alloy, and “nickel” means to include nickel and nickel alloy. Copper plating and nickel plating may be performed by electrolytic plating or electroless plating, respectively, but electrolytic plating is usually employed.

  When copper plating or nickel plating is performed, if the plating layer is too thin, the influence of the underlying surface cannot be completely eliminated. Therefore, the thickness is preferably 50 μm or more. The upper limit of the plating layer thickness is preferably about 500 μm.

  Examples of the metal material suitably used for forming the mold base include aluminum and iron from the viewpoint of cost. From the viewpoint of handling convenience, it is more preferable to use lightweight aluminum. The aluminum and iron here may be pure metals, respectively, or may be an alloy mainly composed of aluminum or iron. Moreover, the shape of the base material for metal mold | die may be an appropriate | suitable shape conventionally employ | adopted in the said field | area, for example, besides a flat form, a cylindrical or cylindrical roll may be sufficient.

[2] Polishing Step In the subsequent polishing step, the surface of the substrate that has been subjected to copper plating or nickel plating in the first plating step described above is polished. It is preferable that the base material surface is grind | polished in the state close | similar to a mirror surface through the said process. This is because metal plates and metal rolls that serve as base materials are often subjected to machining such as cutting and grinding in order to achieve the desired accuracy, and as a result, machine marks remain on the base material surface. This is because even if copper plating or nickel plating is applied, those processed marks may remain, and the surface may not be completely smooth in the plated state. In FIG. 11 (a), a plate-shaped mold substrate 7 is subjected to copper plating or nickel plating on its surface in the first plating step (for the copper plating or nickel plating layer formed in this step). Further, a state in which the surface 8 is mirror-polished by a polishing process is schematically shown.

  There is no particular limitation on the method for polishing the surface of the substrate on which copper plating or nickel plating has been applied, and any of mechanical polishing, electrolytic polishing, and chemical polishing can be used. Examples of the mechanical polishing method include super finishing, lapping, fluid polishing, and buff polishing. As for the surface roughness after polishing, the center line average roughness Ra in accordance with the provisions of JIS B 0601 is preferably 0.1 μm or less, and more preferably 0.05 μm or less. If the centerline average roughness Ra after polishing is greater than 0.1 μm, the final unevenness of the mold surface may remain affected by the surface roughness after polishing.

[3] Photosensitive resin film forming step In the subsequent photosensitive resin film forming step, the photosensitive resin was dissolved in the solvent on the polished surface 8 of the mold substrate 7 that was mirror-polished by the polishing step described above. A photosensitive resin film is formed by applying as a solution, heating and drying. FIG. 11B schematically shows a state in which the photosensitive resin film 9 is formed on the polished surface 8 of the mold base 7.

  A conventionally known photosensitive resin can be used as the photosensitive resin. Examples of the negative photosensitive resin having a property of curing the photosensitive part include, for example, a monomer or prepolymer of an acrylate ester having an acrylic group or a methacrylic group in the molecule, a mixture of bisazide and a diene rubber, polyvinyl Cinnamate compounds and the like can be used. Further, as a positive photosensitive resin having such a property that a photosensitive part is eluted by development and only an unexposed part remains, for example, a phenol resin type or a novolac resin type can be used. Moreover, you may mix | blend various additives, such as a sensitizer, a development accelerator, an adhesiveness modifier, and a coating property improving agent, with a photosensitive resin as needed. When these photosensitive resins are applied to the polished surface 8 of the mold base 7, it is preferable to dilute and apply in an appropriate solvent in order to form a good coating film.

  As a method for applying the photosensitive resin solution, known methods such as meniscus coating, fountain coating, dip coating, spin coating, roll coating, wire bar coating, air knife coating, blade coating, and curtain coating may be used. it can. The thickness of the coating film is preferably in the range of 1 to 6 μm after drying.

[4] Exposure Step In the subsequent exposure step, a pattern corresponding to the desired fine uneven surface shape is exposed on the photosensitive resin film 9 formed in the above-described photosensitive resin film forming step. The light source used in the exposure process may be appropriately selected according to the photosensitive wavelength and sensitivity of the coated photosensitive resin. For example, the g-line (wavelength: 436 nm) of the high-pressure mercury lamp, the h-line (wavelength: 405 nm) of the high-pressure mercury lamp. ), I line (wavelength: 365 nm) of high pressure mercury lamp, semiconductor laser (wavelength: 830 nm, 532 nm, 488 nm, 405 nm, etc.), YAG laser (wavelength: 1064 nm), KrF excimer laser (wavelength: 248 nm), ArF excimer laser (wavelength) 193 nm), F2 excimer laser (wavelength: 157 nm), or the like. Examples of a method for exposing the pattern include laser drawing.

  FIG. 11C schematically shows a state where the pattern is exposed to the photosensitive resin film 9. When the photosensitive resin film is formed of a negative photosensitive resin, the exposed region 10 undergoes a crosslinking reaction of the resin by exposure, and the solubility in a developing solution described later decreases. Therefore, the unexposed area 11 in the developing process is dissolved by the developer, and only the exposed area 10 remains on the substrate surface as a mask. On the other hand, in the case where the photosensitive resin film is formed of a positive photosensitive resin, the exposed region 10 is cut by bonding of the resin by exposure, and the solubility in a developer described later increases. Therefore, the area 10 exposed in the development process is dissolved by the developer, and only the unexposed area 11 remains on the substrate surface as a mask.

[5] Development Step In the subsequent development step, when a negative photosensitive resin is used for the photosensitive resin film 9, the unexposed region 11 is dissolved by the developer, and only the exposed region 10 is gold. It remains on the mold substrate and acts as a mask in the subsequent first etching step. On the other hand, when a positive photosensitive resin is used for the photosensitive resin film 9, only the exposed region 10 is dissolved by the developer, and the unexposed region 11 remains on the mold substrate. It acts as a mask in the subsequent first etching step.

  A conventionally well-known thing can be used about the developing solution used for a image development process. For example, inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, primary amines such as ethylamine and n-propylamine, diethylamine, di-n-butylamine and the like Secondary amines, tertiary amines such as triethylamine, methyldiethylamine, alcohol amines such as dimethylethanolamine, triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, trimethylhydroxyethylammonium hydroxide, etc. Examples include alkaline aqueous solutions such as quaternary ammonium salts, cyclic amines such as pyrrole and piperidine; and organic solvents such as xylene and toluene.

  The development method in the development step is not particularly limited, and methods such as immersion development, spray development, brush development, and ultrasonic development can be used.

  FIG. 11D schematically shows a state in which a development process is performed using a negative photosensitive resin for the photosensitive resin film 9. In FIG. 11C, the unexposed region 11 is dissolved by the developer, and only the exposed region 10 becomes the remaining mask 12 on the substrate surface. FIG. 11E schematically shows a state where development processing is performed using a positive photosensitive resin for the photosensitive resin film 9. In FIG. 11C, the exposed region 10 is dissolved by the developer, and only the unexposed region 11 becomes the remaining mask 12 on the substrate surface.

[6] First Etching Step In the subsequent first etching step, the mold base is mainly used in a portion where there is no mask, using the photosensitive resin film remaining on the mold base surface after the development step as a mask. The material is etched to form irregularities on the polished plated surface. FIG. 12 is a diagram schematically illustrating a preferred example of the latter half of the method for manufacturing a mold for anti-glare treatment suitable as an inspection object. FIG. 12A schematically shows a state in which the mold base 7 in a portion 13 where no mask is mainly etched by the first etching step. The mold base 7 below the mask 12 is not etched from the mold base surface, but etching from the portion 13 without the mask proceeds with the progress of etching. Therefore, in the vicinity of the boundary between the mask 12 and the portion 13 without the mask, the mold base 7 under the mask 12 is also etched. In the vicinity of the boundary between the mask 12 and the portion 13 without the mask, the die base material 7 below the mask 12 is also etched, which is hereinafter referred to as side etching. FIG. 13 schematically shows the progress of side etching. The dotted line 14 in FIG. 13 shows the surface of the mold base material that changes with the progress of etching in stages.

The etching process in the first etching step is usually performed using a ferric chloride (FeCl ₃ ) solution, a cupric chloride (CuCl ₂ ) solution, an alkali etching solution (Cu (NH ₃ ) ₄ Cl ₂ ), etc. Although it is performed by corroding the surface, a strong acid such as hydrochloric acid or sulfuric acid can be used, or reverse electrolytic etching by applying a potential opposite to that during electrolytic plating can also be used. Although the concave shape formed on the mold base material when the etching process is performed differs depending on the type of the base metal, the type of the photosensitive resin film, the etching technique, and the like, the etching amount is 10 μm. In the following cases, etching is performed approximately isotropically from the metal surface in contact with the etching solution. The etching amount here is the thickness of the base material to be cut by etching.

  The etching amount in the first etching step is preferably 1 to 50 μm. When the etching amount is less than 1 μm, the metal surface is hardly formed with an uneven shape and becomes a substantially flat mold, which is not suitable as an antiglare mold. In addition, when the etching amount exceeds 50 μm, the height difference of the concavo-convex shape formed on the metal surface becomes large, and in the image display device to which the antiglare film produced using the obtained mold is applied, it is white. There is a risk of injury. The etching process in the first etching step may be performed by one etching process, or the etching process may be performed twice or more. In the case where the etching process is performed twice or more, the total etching amount in the two or more etching processes is preferably 1 to 50 μm.

[7] Photosensitive resin film peeling step In the subsequent photosensitive resin film peeling step, the remaining photosensitive resin film used as a mask in the first etching step is completely dissolved and removed. In the photosensitive resin film peeling step, the photosensitive resin film is dissolved using a peeling solution. As the stripper, the same developer as that described above can be used. The peeling method in the photosensitive resin film peeling step is not particularly limited, and methods such as immersion development, spray development, brush development, and ultrasonic development can be used. FIG. 12B schematically shows a state where the photosensitive resin film used as the mask 12 in the first etching process is completely dissolved and removed by the photosensitive resin film peeling process. The first surface irregularities 15 are formed on the surface of the mold substrate by etching using the mask 12 made of a photosensitive resin film.

[8] Second plating step Subsequently, the surface unevenness shape is blunted by performing chromium plating on the formed uneven surface (first surface unevenness shape 15). In FIG. 12 (c), by forming the chrome plating layer 16 on the first surface irregularity shape 15, a surface (chromium plating surface 17) whose irregularities are duller than the first surface irregularity shape 15 is formed. The state is shown.

The type of chrome plating is not particularly limited, but it is preferable to use a chrome plating that expresses a good gloss, so-called gloss chrome plating or decorative chrome plating. Chromium plating is usually performed by electrolysis, and an aqueous solution containing chromic anhydride (CrO ₃ ) and a small amount of sulfuric acid is used as the plating bath. By adjusting the current density and electrolysis time, the thickness of the chromium plating can be controlled.

  In the above-described mold manufacturing method, a chrome plating is applied to the surface on which the fine surface irregularities are formed, whereby a mold with the irregularities being blunted and the surface hardness being increased can be obtained. The bluntness of the irregularities at this time varies depending on the type of the base metal, the size and depth of the irregularities obtained from the first etching process, and the type and thickness of the plating. The greatest factor in controlling is the plating thickness. When the thickness of the chrome plating is thin, the effect of dulling the surface shape of the unevenness obtained before the chrome plating process is insufficient, and the antiglare obtained by transferring the uneven shape onto a transparent substrate such as a transparent film. The optical properties of the transparent substrate (such as an antiglare film) subjected to the treatment are not so good. On the other hand, when the plating thickness is too thick, productivity is deteriorated and a projection-like plating defect called a nodule is generated, which is not preferable. Therefore, the thickness of the chrome plating is preferably in the range of 1 to 10 μm, and more preferably in the range of 3 to 6 μm.

  The chromium plating layer formed in the second plating step is preferably formed to have a Vickers hardness of 800 or more, and more preferably 1000 or more.

  Moreover, the 2nd etching process of blunting the uneven | corrugated surface formed by the 1st etching process by an etching process between the [7] photosensitive resin film peeling process mentioned above and the [8] 2nd plating process may be included. preferable. In the second etching process, the first surface irregularities 15 formed by the first etching process using the photosensitive resin film as a mask are blunted by an etching process. By this second etching process, there is no portion with a steep surface inclination in the first surface irregularity shape 15 formed by the first etching process, and an anti-glare film such as an anti-glare film manufactured using the obtained mold. The optical properties of the transparent substrate subjected to the treatment change in a preferable direction. In FIG. 14, the first surface unevenness shape 15 of the mold base 7 is blunted by the second etching process, the portion having a steep surface inclination is blunted, and the second surface unevenness having a gentle surface inclination is obtained. The state where the shape 18 is formed is shown.

Similarly to the first etching step, the etching process in the second etching step is usually ferric chloride (FeCl ₃ ) solution, cupric chloride (CuCl ₂ ) solution, alkaline etching solution (Cu (NH ₃ ) ₄ Cl ₂ ) or the like, and by corroding the surface, strong acid such as hydrochloric acid or sulfuric acid can be used, or reverse electrolytic etching by applying a potential opposite to that during electrolytic plating can also be used. The bluntness of the unevenness after the etching process varies depending on the type of the underlying metal, the etching technique, and the size and depth of the unevenness obtained by the first etching process. The largest factor in controlling the amount is the etching amount. The etching amount here is also the thickness of the base material to be cut by etching, as in the first etching step. If the etching amount is small, the effect of dulling the surface shape of the unevenness obtained by the first etching step is insufficient, and the antiglare treatment obtained by transferring the uneven shape onto a transparent substrate such as a transparent film The optical properties of the applied transparent substrate (such as an antiglare film) are not so good. On the other hand, when the etching amount is too large, the uneven shape is almost lost, and a substantially flat mold is obtained. Therefore, the etching amount is preferably in the range of 1 to 50 μm, and more preferably in the range of 4 to 20 μm. Similarly to the first etching process, the etching process in the second etching process may be performed by one etching process, or the etching process may be performed twice or more. In the case where the etching process is performed twice or more, the total etching amount in the two or more etching processes is preferably 1 to 50 μm.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

<Example 1>
An automatic inspection apparatus for inspecting defects on the surface of the fine irregularities formed on the side surface of the anti-glare roll 201 having a diameter of 200 mm and a width of 650 mm was produced. FIG. 15 shows an outline of the inspection apparatus manufactured in this example.

  As the two-dimensional imaging device 101, a 5 million pixel CCD camera CV-H500C (manufactured by Keyence Corporation) equipped with a low distortion lens CA-LH50 having a focal length of 50 mm and a close-up ring OP-51612 (both manufactured by Keyence Corporation). This was used and placed at a position where the distance between the tip of the CA-LH 50 and the mold 201 to be inspected was 240 mm. The optical system was adjusted so as to image a range of about 35 mm square on the fine uneven surface of the mold 201. One pixel of the two-dimensional imaging device 101 corresponds to 15 μm on the fine uneven surface.

  The two-dimensional imaging device 101 is connected to a camera controller integrated image processing system CV-5700 (manufactured by Keyence Corporation), which is the image processing means 108 and camera controller 109, via Ethernet, and the CV-5700 includes the arithmetic means 107, The storage unit 110 and the personal computer Vostro220 (manufactured by Dell) as the control unit 111 were connected via Ethernet.

  White LED bar illumination CA-DBW13 (made by Keyence Corporation, width w = 15 mm) as the first illumination 102 and white LED flat panel illumination CA-DASW15 (made by Keyence Corporation, width w =) as the second illumination 103 150 mm) was connected to the illumination controller CA-DC20E, which is the light intensity control means 106, respectively. The installation positions of the first illumination 102 and the second illumination 103 in the inspection apparatus are as shown in FIG. 15. In the image obtained by the two-dimensional imaging device 101, the first bright portion 301, the dark portion 303, and The second bright portions 302 were installed in this order and at positions where they were arranged in parallel to the rotational symmetry axis of the roll mold 201 to be inspected. The CA-DC 20E has a function of controlling the light intensity of the illumination via Ethernet by connecting to the CV-5700. In this embodiment, the CA-DC 20E uses the function to control the first illumination 102 and The intensity of light emitted from the second illumination 103 is controlled. That is, in the present embodiment, the CA-DC 20E which is the light intensity control means 106 is connected to the CV-5700 via the Ethernet, and is irradiated from the first illumination 102 and the second illumination 103 from the personal computer. It was set as the structure which can control the intensity | strength of light.

  As the first moving unit 104 and the second moving unit 105, as in FIG. 1, servo linear holding a base that holds the two-dimensional imaging device 101, the first illumination 102, and the second illumination 103, respectively. An actuator EXZ9LH-80WA (made by Oriental Motor Co., Ltd.) and a stepping motor AR98AA-H50-2 (made by Oriental Motor Co., Ltd.) that rotates a mold were used. These moving means are configured to be connected to the controller EMP 402-1, which is the motor controller 112, and to control the controller EMP 402-1 from the personal computer via the RS232C (serial port).

  The inspection apparatus of the present embodiment shown in FIG. 15 having the above-described configuration has a concave defect whose maximum inclination angle x is about 2.8 ° or more and a convex defect whose maximum inclination angle x ′ is about 3.5 ° or more. It can be detected.

  Using the inspection apparatus configured as described above, a defect inspection was performed on the fine uneven surface formed on the side surface of the roll mold 201. First, the intensity of the first illumination 102 and the second illumination 103 was adjusted as follows. A roll mold 201 is placed on the stepping motor, and the first light 102 and the second light 103 are irradiated with the first light and the second light, respectively, toward the fine uneven surface, and an image of the irradiation region is obtained. Was acquired by the two-dimensional imaging device 101, converted into image data by CV-5700, and transferred to the personal computer. In the storage means 110 of the personal computer, three designated points are designated in advance, that is, the central point of the first bright part 301, the central point of the first inspection area 310, and the central point of the second bright part 302. The brightness is stored, and the specified brightness value is compared with the brightness value at the specified point extracted by the personal computer from the transferred image data. According to the flowchart shown in FIG. The intensities of the first light and the second light were adjusted so that the lightness value at the designated point was approximately the designated lightness value. The final brightness values at the three points on the image data were 255 (designated brightness value is 255), 206 (designated brightness value is 200), and 231 (designated brightness value is 230), respectively. Note that the brightness value at the designated point extracted from the image data was the average value of pixels corresponding to a width of 150 μm.

  As described above, after adjusting the intensity of the first light and the second light, the imaging range of the two-dimensional imaging device was moved to the inspection range, and the inspection was performed. First, in the same manner as described above, an image of the inspection range is acquired by the two-dimensional imaging device 101, converted into image data by CV-5700, and the image data is corrected by applying a shading correction filter and a contrast correction filter. Further, pixel coordinates where a bright point (corresponding to a dent defect) and a dark spot (corresponding to a convex defect) in the first inspection region and the second inspection region in the inspection range are extracted and transferred to a personal computer. did. Next, the position coordinate information of the moving means is calculated by the CPU of the personal computer, and based on this and the pixel coordinates where the bright point and the dark point exist, absolute coordinates of the bright point and the dark point are obtained. Stored in the storage means 110.

  Next, the two-dimensional imaging device 101, the first illumination 102, and the second illumination 103 are integrally moved by 30 mm in a direction parallel to the rotational symmetry axis of the roll mold 201 by the first moving means 104. And inspected in the same manner as described above. After repeating a similar operation and inspecting a series of fine uneven surfaces along a direction parallel to the rotational symmetry axis of the mold, the second moving means 105 rotates the roll mold 201 by 2 mm in surface length. Again, a series of microscopic surface irregularities along the direction parallel to the rotational symmetry axis of the mold were inspected. The above operation was performed on the entire outer periphery of the roll mold, and the inspection of the entire surface of the fine irregularities of the mold was completed.

  The inspection was performed as described above, and the surface of the roll mold 201 was observed with an optical microscope based on the coordinates stored in the storage unit 110. Moreover, the film by which the fine uneven | corrugated shape of the roll metal mold | die 201 was transferred using the roll metal mold | die 201 was produced, and the fine uneven | corrugated shape of the said film was observed with the confocal microscope.

  As a result, the roll mold 201 has a diameter of about 100 μm at a position corresponding to the coordinate position stored in the storage unit 110 and a depth of about 2 μm (the depth is a result of observing the fine uneven shape of the transfer film). (Estimated value from)) and a concave defect having a minimum diameter of about 50 μm and a depth of about 2 μm (the depth is an estimated value based on the observation result of the fine uneven shape of the transfer film). It was.

  From the above results, it can be seen that according to the inspection apparatus of the present invention, both the dent defect and the convex defect can be detected with high accuracy.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  7 substrate for mold, 8 surface of substrate polished by polishing process, 9 photosensitive resin film, 10 photosensitive resin film exposed in exposure process, 11 photosensitive resin film not exposed in exposure process, 12 mask , 13 Location without mask, 14 Surface formed stepwise by etching, 15 Substrate surface after first etching step (first surface irregular shape), 16 Chromium plating layer, 17 Chromium plating surface, 18th 2 Substrate surface (second surface irregular shape) after the etching process, 101 two-dimensional imaging device, 102 first illumination, 103 second illumination, 104 first moving means, 105 second moving means, 106 Light intensity control means, 107 calculation means, 108 image processing means, 109 camera controller, 110 storage means, 111 control means, 112 motor Controller, 201 Mold, 300 Image (image data) obtained by two-dimensional imaging device 101, 301 1st bright part, 302 2nd bright part, 303 dark part, 310 1st inspection area, 320 2nd inspection region.

Claims (11)

An inspection apparatus for detecting a dent defect and / or a convex defect on the surface of a mold for anti-glare treatment,
A first illumination for irradiating the mold surface with a first light;
A second illumination for irradiating the mold surface with a second light;
A two-dimensional imaging device for acquiring an image of a partial region of a mold surface including a region irradiated with the first light and the second light;
Light intensity control means for controlling the intensity of the first light and the second light;
Computing means for computing the difference between the brightness at a predesignated point on the image obtained by the two-dimensional imaging device and the predesignated brightness or a predesignated brightness range for the point;
A mold inspection apparatus comprising:   The two-dimensional imaging device, the first illumination, and the second illumination are, in an image obtained by the two-dimensional imaging device, a first bright portion caused by scattering of the first light, and the second illumination Located between the second bright part due to light scattering, the first bright part and the second bright part, and lighter than the first bright part and the second bright part. The mold inspection apparatus according to claim 1, wherein the mold inspection apparatus is arranged so as to generate a dark part having a low level.   Based on the calculation result of the calculation means, the light intensity control means causes the lightness at a predesignated point on the image to be within the predesignated lightness or the predesignated lightness range. The mold inspection apparatus according to claim 1, wherein the intensity of the first light and / or the second light is controlled.   4. The mold inspection according to claim 2, wherein the predetermined points on the image include at least one point in the first bright portion and at least one point in the second bright portion. apparatus.   The mold according to any one of claims 2 to 4, wherein the intensity of the first light is controlled by the light intensity control means so that the first bright portion shows the maximum brightness in the image. Inspection equipment.   By detecting the presence / absence of a bright spot in the dark part side end region of the first bright part and / or the presence / absence of a dark spot in the second bright part, the concave defect and / or the The mold inspection apparatus according to claim 2, wherein presence or absence of a convex defect is detected. A straight line parallel to the optical axis of the two-dimensional imaging device passes through the center point T of the region corresponding to the dark part on the mold surface, and passes through the center point T whose angle formed with the straight line M is 2α. When a straight line is defined as a straight line N (here, α [°] is an angle formed by a normal line of the surface obtained by averaging the regions irradiated with the first light on the mold surface and the straight line M). The first illumination satisfies the following formula (1) when arranged in the region R defined by the straight line M and the straight line N, and satisfies the following formula (2) when arranged outside the region R. The mold inspection apparatus according to claim 2, which is arranged as described above.
θ _E1 ≦ 2α-2x (1)
θ _E1 ≧ 2α + 2x (2)
[Where θ _E1 [°] is an angle formed by the straight line M and a straight line connecting the point L _E1 on the end of the straight line N side and the center point T in the first illumination, and x [° ] Is the minimum value of the maximum inclination angle of each of the dent-like defects that can exist on the mold surface, that the defect to be detected has. ] A straight line passing through the center point T ′ of the region corresponding to the second bright portion on the mold surface and parallel to the optical axis of the two-dimensional imaging device is defined as a straight line M ′, and an angle formed by the straight line M ′ is 2α. When a straight line passing through the center point T, which is' is a straight line N '(where α' [°] is the normal of the surface averaged over the region irradiated with the second light on the mold surface) And the straight line M ′.), The second illumination is arranged on the straight line N ′ so as to satisfy the following expressions (3) and (4). The mold inspection device described in 1.
θ ′ _E1 > 2α′−2x ′ (3)
θ ′ _E2 <2α ′ + 2x ′ (4)
[Where, θ ′ _E1 [°] is an angle formed by the straight line M ′ and a straight line connecting the point L ′ _E1 and the center point T ′ on the end of the second line on the straight line M ′ side. Yes, θ ′ _E2 [°] is an angle formed by the straight line M ′ and a straight line connecting the point L ′ _E2 and the center point T ′ on the end opposite to the straight line M ′ side in the second illumination. X ′ [°] is the minimum value of the defects to be detected among the maximum inclination angles of the respective convex defects that can exist on the mold surface. ]   The mold inspection apparatus according to claim 1, further comprising a moving unit that moves a position on the mold surface of a region irradiated with the first light and the second light.   The moving means includes means for moving the two-dimensional imaging device, the first illumination, and the second illumination with respect to a mold while maintaining a relative positional relationship with each other. Mold inspection equipment.   The mold inspection apparatus according to claim 1, further comprising image processing means for performing shading correction on an image obtained by the two-dimensional imaging device.