JP4675160B2 - Optical inspection apparatus and optical film bonded product manufacturing apparatus - Google Patents

Description

 The present invention relates to an optical inspection method and apparatus suitably applied during the manufacture of an optical film bonded product such as a liquid crystal bonded panel, and an optical film bonded product manufacturing to which the optical inspection method and the apparatus are applied. The present invention relates to a method and an apparatus thereof.

Conventionally, bonded substrates such as a liquid crystal bonded panel have been proposed and used in various fields. A method of manufacturing a bonded substrate has also been proposed and put into practical use.
First, a manufacturing process of a TFT color liquid crystal substrate as an example of a bonded substrate will be described.

 In the liquid crystal substrate manufacturing process and the array process, a glass called mother glass that chamfers multiple panels is used as a substrate, and the process of cleaning, film formation, resist coating, exposure, development, etching, and resist stripping is repeated multiple times to form a fine pattern. Form. And since the foreign substance and pattern defect of this pattern formation surface (henceforth a surface) become a killer defect of a product, the inspection is made many times in each process and between processes. This is almost the same in the color filter process. On the other hand, on the back side, foreign matter of several microns is not considered to be a product defect and it is considered that inspection is unnecessary. Therefore, the back side was hardly inspected.

  Each substrate is sent to the cell process from the array process and the color filter process, and the two substrates are bonded together. Thereafter, liquid crystal is injected between the substrates and sealed, and a polarizing plate is attached to complete a liquid crystal cell. The liquid crystal cell manufactured in this way is guaranteed to have no foreign matter or pattern defects on the pattern surface.

 Further, as an apparatus for inspecting the surface state, both the optical axis of the illumination unit and the optical axis of the detection unit are inclined with respect to the surface to be measured, and the illumination unit includes the optical axis of the illumination unit and the optical axis of the detection unit. There has been proposed one in which linearly polarized light polarized in a direction substantially parallel to a plane is incident on a surface to be examined (see Patent Document 1).

 Furthermore, the sample surface has a laser pattern projector that irradiates light onto the surface of the sample held on the inspection stage and a linear array sensor that receives scattered light from the sample surface, and the sample surface is based on the received scattered light intensity. There has also been proposed an apparatus for inspecting the presence or absence of foreign matter (see Patent Document 2).

Furthermore, an apparatus that includes an illumination light source, a lens array, and a line sensor and detects the position and size of a foreign substance based on the position and light intensity of the detected scattered light has been proposed (see Patent Document 3).
Japanese Patent No. 3253177 JP 2001-272355 A JP 2004-53972 A

  In the conventional process for manufacturing a bonded substrate, especially after the completion of the liquid crystal cell, foreign matter is not inspected, so in the last step of attaching the polarizing plate, foreign matters etc. are mixed in to cause product defects. There is an inconvenience.

  Product defects indicate that foreign matter was mixed in the process of laminating the polarizing plate for the first time by the lighting inspection after laminating the polarizing plate, and the polarizing plate was peeled off and discarded. Bonding results in waste of the polarizing plate and waste of the process.

  Further, it is conceivable that a visual inspection is performed by an inspector before the polarizing plate is bonded, but only a foreign substance having a certain size or more can be detected, and there is an inconvenience that oversight occurs.

In addition, the inspection apparatus according to any one of Patent Document 1 to Patent Document 3 cannot achieve sufficient size reduction, weight reduction, and cost reduction, but also cannot obtain sufficient inspection accuracy.
The present invention has been made in view of the above problems, an optical inspection method capable of achieving sufficient size reduction, weight reduction, and cost reduction, and sufficient inspection accuracy, and its A first object is to provide an apparatus, and a second object is to provide an optical film bonded product manufacturing method and apparatus using the optical inspection method and the apparatus.

Light source means (1) for irradiating light at a predetermined angle to the surface opposite to the pattern formation surface of the substrate on which a fine pattern is formed, and a telecentric lens array (for obtaining an erect image by inputting scattered light from the opposite surface) 2), a line sensor (3) for receiving an erect image, and image processing means for inspecting the presence or absence of a foreign substance based on the erect image, and the number of columns of the telecentric lens array (2) has a maximum incident angle. Optical inspection, wherein θ is the minimum integer N satisfying arctan ((2N−1) r / WD) ≧ θ where r is the lens radius and WD is the distance between the lens and the substrate. apparatus.

The optical inspection apparatus according to claim 1, wherein a maximum incident angle of the telecentric lens array (2) is not less than 10 degrees and not more than 20 degrees.

The optical inspection apparatus according to claim 1, wherein the element size of the line sensor (3) is not less than 30 µm square and not more than 50 µm square.

An apparatus for manufacturing an optical film bonded product by bonding a pair of substrates on which a fine pattern is formed with their pattern formation surfaces facing each other and then bonding an optical film to the surface opposite to the pattern formation surface of the substrate. A light source means for irradiating light at a predetermined angle with respect to a surface opposite to a pattern forming surface of a substrate on which a fine pattern is formed in a step after bonding of a pair of substrates and before bonding of an optical film; A telecentric lens array that obtains an erect image by inputting scattered light from the opposite surface, a line sensor that receives the erect image, and an image processing means that inspects for the presence of foreign matter based on the erect image, and the telecentric lens The number of columns in the array is as follows: arctan ((2N−1) r /) where θ is the maximum incident angle, r is the lens radius, and WD is the distance between the lens and the substrate. D) ≧ theta smallest optical film bonded product manufacturing apparatus, characterized in that an integer N that satisfies.

The optical film bonded product manufacturing apparatus according to claim 5, wherein a maximum incident angle of the telecentric lens array is 10 degrees or more and 20 degrees or less .

The optical film bonded product manufacturing apparatus according to claim 5, wherein an element size of the line sensor is 30 μm square or more and 50 μm square or less .

  The optical inspection method of the present invention can accurately inspect for the presence or absence of foreign matter on the surface opposite to the pattern forming surface of the substrate, and can achieve sufficient size reduction, weight reduction, and cost reduction. There is a unique effect.

  The optical inspection apparatus of the present invention can accurately inspect the presence or absence of foreign matter on the surface opposite to the pattern forming surface of the substrate, and can achieve sufficient size reduction, weight reduction, and cost reduction. There is a unique effect.

  The method for producing an optical film-bonded product of the present invention has a specific effect that it is possible to prevent the occurrence of defective products by bonding the optical film in the presence of foreign matter.

  The optical film bonded product manufacturing apparatus of the present invention has a specific effect that it is possible to prevent the occurrence of defective products by bonding optical films in the presence of foreign matter.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of an optical inspection method and apparatus and an optical film bonded product manufacturing method and apparatus according to the present invention will be described below in detail with reference to the accompanying drawings.

  FIG. 1 is a process diagram for explaining an embodiment of a method for producing an optical film-bonded product of the present invention. In FIG. 1, a liquid crystal substrate manufacturing process is taken as an example.

In this liquid crystal substrate manufacturing process, a glass substrate is repeatedly subjected to a cleaning process, a film forming process, a resist coating process, an exposure process, a developing process, an etching process, and a resist stripping process in this order, and then an alignment film coating process. Then, a rubbing process and a spacer coating process are performed to manufacture a TFT.
In addition, the glass substrate is repeatedly subjected to a cleaning process, a film forming process, a resist coating process, an exposure process, a developing process, an etching process, and a resist stripping process in this order a plurality of times, followed by an alignment film coating process and a rubbing process. To produce color filters.

After manufacturing the TFT and the color filter as described above, a bonding process, a liquid crystal injection process, a sealing process, a foreign substance inspection process, and a polarizing plate bonding process are performed to complete a liquid crystal cell.
The foreign substance inspection process will be described in detail below, but the other processes are conventionally known, and thus detailed description thereof is omitted.

  FIG. 2 is a side view schematically showing an embodiment of a foreign substance inspection apparatus used for foreign substance inspection processing, FIG. 3 is a front view of the same, and FIG. 4 is a plan view of the main part of the same.

  This foreign matter inspection apparatus includes a line illumination 1 that irradiates light at a predetermined angle to a surface 5 opposite to a pattern formation surface of a glass substrate, and a telecentric lens array 2 that obtains an erect image by inputting scattered light from the opposite surface. And a long line sensor 3 that receives an erect image and an image processing unit (not shown) that inspects for the presence of foreign matter based on the erect image.

  The telecentric lens array 2 is formed by arranging a plurality of telecentric lenses 2a having a radius r, and preferably the number of array rows is set to N as shown in FIG.

  The distance between the incident surface of the telecentric lens array 2 and the surface opposite to the pattern forming surface of the glass substrate is set to WD (see FIG. 2), and the incident angle of the telecentric lens in this state is rθ. (See FIG. 2) The maximum incident angle of the telecentric lens array 2 is θ (see FIG. 3).

  The number N of array rows of the telecentric lenses 2a is preferably set to the smallest integer that satisfies arctan ((2N−1) r / WD) ≧ θ. This is because if the number of rows of the telecentric lens array 2 (the number of rows of the telecentric lenses 2a) is less than the minimum integer N, the sensitivity is low, and conversely, the number of columns of the telecentric lens array 2 is the minimum integer N. This is because if the number is larger than that, the improvement in sensitivity can hardly be expected, but the size is increased.

  Moreover, it is preferable that the maximum incident angle of the telecentric lens array 2 is 10 degrees or more and 20 degrees or less. This is because if the maximum incident angle is less than 10 degrees, the sensitivity is low, and conversely, if the maximum incident angle is larger than 20 degrees, the aberration becomes large and the sensitivity approaches a saturated state. Because you can hardly expect.

  Furthermore, the element size of the line sensor 3 is preferably 30 μm square or more and 50 μm square or less. This is because if the element size is less than 30 μm square, the sensitivity is low and the inspection speed is slow, and conversely, if the element size is larger than 50 μm square, the position resolution is deteriorated and the presence coordinates of the foreign matter are deteriorated. This is because the accuracy deteriorates.

FIG. 5 is a perspective view schematically showing an embodiment of the foreign matter inspection apparatus.
This foreign matter inspection apparatus supports a substrate to be inspected (substrate before attaching an optical film) 13 on a base 11, and sandwiches the supported substrate to be inspected 13 on the base 11 so as to face each other. The slider 12 is provided with an inspection head 14 that is supported by the slider 12 and reciprocates in a predetermined direction.

  2 and 3 is incorporated in the inspection head 14 as an illumination system, and the telecentric lens array 2 and the long line sensor 3 are incorporated as a detection system.

  However, instead of reciprocating the inspection head 14, the inspection target substrate 13 can be reciprocated.

  Further, although not shown in FIG. 5, the image processing unit (not shown) for inspecting the presence / absence of a foreign substance based on the erect image is provided.

  The operation of the foreign substance inspection apparatus having the above-described configuration is as follows.

  The inspection target substrate 13 is supported on the base 11, and the position of the inspection head 14 is set by the slider 12. In this state, the inspection target substrate 13 is illuminated by the line illumination 1, and scattered light from the inspection target substrate 13 is emitted. As an input, an erect image is obtained by the telecentric lens array 2 and received by the long line sensor 3. Then, an output signal from the long line sensor 3 representing the received light intensity is supplied to an image processing unit (not shown).

  Here, if there is no foreign matter, the intensity of light received by the long line sensor 3 is low over the entire range, but if there is foreign matter, the intensity of light received by the long line sensor 3 is Corresponding to the position of the foreign material, it becomes extremely high and the remaining range is low.

  Next, the position of the inspection head 14 is changed by the slider 12, and the same processing as described above is performed in this state.

  Then, the process of changing the position of the inspection head 14 by the slider 12 is performed for the entire range of the inspection target substrate 13.

  In the image processing unit, for example, by comparing the output signal from the long line sensor 3 with a preset threshold value, the presence / absence of a foreign substance and, if applicable, the position of the foreign substance (element of the long line sensor 3) Position and a position determined by the inspection head position) can be detected.

  Here, since the difference in light intensity corresponding to the presence or absence of foreign matter is sufficiently large, the threshold can be set easily.

Then, only when it is detected that no foreign matter is present, the polarizing plate (optical film) can be bonded to prevent the occurrence of defective products due to the foreign matter.
On the other hand, when it is detected that a foreign substance is present, a process for removing the foreign substance (for example, a cleaning process) may be performed, and then an inspection for the presence or absence of the foreign substance may be performed again.

  FIG. 6 is an enlarged partial sectional view schematically showing the configuration of the liquid crystal cell.

  In the illustrated liquid crystal cell, a polarizing plate is to be attached in a state where foreign matter exists on both the color filter side and the TFT side.

  However, if the optical film bonded product manufacturing method of FIG. 1 is adopted, the presence or absence of foreign matter is inspected before the polarizing plates are bonded together, so that the occurrence of defective products can be prevented in advance.

  Further, the foreign substance inspection apparatus of FIG. 5 needs to inspect one surface of the substrate to be inspected and then turn over the substrate to be inspected to inspect the other surface, but can inspect both surfaces of the substrate to be inspected at the same time. Thus, it is preferable to provide inspection heads above and below the substrate to be inspected, and in this case, the time required for inspection can be almost halved.

  FIG. 7 is a diagram showing an example of a signal obtained by the foreign object detection process, and it can be seen that a remarkably large signal is obtained corresponding to only the position where the foreign substance exists. FIG. 7 shows a case where a foreign matter of about 10 μm is detected.

  Therefore, it is easy to set a threshold value for discriminating a signal when there is a foreign object and a signal when there is no foreign object.

It is process drawing explaining one Embodiment of the optical film bonded product manufacturing method of this invention. It is a side view which shows roughly one Embodiment of the foreign material inspection apparatus used for a foreign material inspection process. It is a front view same as the above. It is a top view of the principal part same as the above. It is a perspective view showing roughly one embodiment of a foreign substance inspection device. It is an expanded partial sectional view which shows the structure of a liquid crystal cell roughly. It is a figure which shows an example of the signal obtained by a foreign material detection process.

Explanation of symbols

1 Line illumination 2 Telecentric lens array 3 Long line sensor

Claims (6)

Light source means (1) for irradiating light at a predetermined angle to a surface opposite to the pattern forming surface of the substrate on which a fine pattern is formed, and a telecentric lens array (for obtaining an erect image by inputting scattered light from the opposite surface) 2), a line sensor (3) for receiving an erect image, and image processing means for inspecting for the presence of foreign matter based on the erect image ,
The number of columns of the telecentric lens array (2) is arctan ((2N−1) r / WD) ≧ θ, where θ is the maximum incident angle, r is the lens radius, and WD is the distance between the lens and the substrate. An optical inspection apparatus characterized by being the smallest integer N satisfying The optical inspection apparatus according to claim 1 , wherein a maximum incident angle of the telecentric lens array (2) is not less than 10 degrees and not more than 20 degrees. The optical inspection apparatus according to claim 1 , wherein the element size of the line sensor (3) is not less than 30 µm square and not more than 50 µm square. An apparatus for manufacturing an optical film bonded product by bonding a pair of substrates on which a fine pattern is formed with their pattern formation surfaces facing each other and then bonding an optical film to the surface opposite to the pattern formation surface of the substrate. There,
The light source means for irradiating light at a predetermined angle with respect to the surface opposite to the pattern forming surface of the substrate on which the fine pattern is formed in the step before the bonding of the pair of substrates and before the bonding of the optical film, A telecentric lens array that obtains an erect image by inputting scattered light from the surface, a line sensor that receives the erect image, and an image processing means that inspects for the presence of foreign matter based on the erect image ,
The number of rows of the telecentric lens array is the minimum satisfying arctan ((2N−1) r / WD) ≧ θ, where θ is the maximum incident angle, r is the lens radius, and WD is the distance between the lens and the substrate. An optical film-laminated product manufacturing apparatus, wherein the optical film is an integer N. The optical film bonded product manufacturing apparatus according to claim 4 , wherein a maximum incident angle of the telecentric lens array is 10 degrees or more and 20 degrees or less. The optical film bonded product manufacturing apparatus according to claim 4 , wherein an element size of the line sensor is 30 μm square or more and 50 μm square or less.