JP2009174957A - Foreign matter detection method and foreign matter detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that the detection of the foreign matter adhered to the back of a glass substrate is difficult by a conventional method for detecting the foreign matter by irradiating the glass substrate, which forms a flat display, with a laser beam and observing the scattered beam from the surface of the glass substrate. <P>SOLUTION: This foreign matter detector is provided with a work stand 4, which has a suction function, having an inspection target such as the glass substrate 1 or the like mounted thereon, a laser beam source 2 for emitting a laser beam almost in parallel to the surface of the inspection target to irradiate the surface of the inspection target, and a light receiver 3 for observing the spot shape of the laser beam. The foreign matter 10 adhered to or present on the back of the inspection target is detected by a change in the spot shape of the laser beam. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for detecting a foreign substance adhering to or existing on a glass substrate or the like forming a flat display in a process of manufacturing a flat display such as a liquid crystal display (LCD), a plasma display (PDP), or an organic EL display, and a detection function thereof. It is related with the foreign material detection apparatus provided with.

  A flat display is configured by forming RGB color filters on a glass substrate. A configuration and a manufacturing method of a general TFT liquid crystal display are introduced in, for example, the following Patent Document 1.

That is, the TFT liquid crystal display is composed of an array substrate and a filter substrate. The filter substrate is formed on a glass substrate with a black matrix, a color filter composed of R, G, and B colored films, a planarizing resin film, and a transparent electrode. On the other hand, the array substrate has a signal line, a scanning line, an active element composed of a TFT, and a pixel electrode formed on a glass substrate.
Alignment films are formed on the opposing surfaces of the filter substrate and the array substrate, respectively. The filter substrate and the array substrate are sandwiched between spherical or columnar spacers, the gap is filled with liquid crystal, and the periphery is fixed with a sealing material. Furthermore, a polarizing plate is affixed on the front and back according to the use of a liquid crystal display.

The filter substrate and array substrate manufacturing method uses photolithography similar to LSI.
Formation of the black matrix of the filter substrate is performed by laminating a colored film on which a pigment-dispersed resin black resist has been applied in advance on a glass substrate, or by applying the pigment-dispersed resin black resist by a spinner method and a die coater method. It exposes through a photomask and patterning the black matrix of a required pattern shape by subsequent image development.

  Similarly, the R, G and B filters are formed in a predetermined pattern shape by applying a color pigment resist film, exposing and developing.

  A die coater method in which a paste such as a pigment-dispersed resin black resist is applied to a glass substrate with a certain thickness from the slit of the die head is introduced in the following Patent Document 2 and the like.

  In such a photolithography process, if any foreign matter adheres to or exists on a glass substrate or the like on which the flat display is formed, the performance of the flat display may be impaired, and the foreign matter may damage the manufacturing apparatus. As a result, the quality and stability of the manufacturing process are reduced, and the product yield of the entire manufacturing process is also reduced. Therefore, it is important to detect foreign substances such as glass substrates in the flat display manufacturing process.

  Therefore, as a conventional example of the foreign matter detection method, there is a method using laser light as shown in Patent Documents 3 and 4 below. In this method, the surface of the object to be inspected is irradiated with laser light, and the scattered light from the surface is received by a photodetector placed above the object to be inspected, and foreign matter is identified according to its intensity. .

Further, in the manufacture of flat displays, foreign matter adhering to or existing on the back surface of a glass substrate or the like may impair the performance of the flat display or damage the manufacturing apparatus in the same manner as foreign matter on the front surface. However, in Patent Documents 3 and 4 below, foreign substances attached to or existing on the surface of an object to be inspected such as a glass substrate can be detected, but it is difficult to detect foreign substances attached to or present on the back surface.
JP 2002-350860 A Japanese Patent Laid-Open No. 2001-137764 JP-A-6-258230 JP 2007-1113930 A

  In the photolithography process as described above, if any foreign matter adheres to or exists on a glass substrate or the like that forms the flat display, the performance of the flat display may be impaired. In particular, in the die coater method, the foreign matter is a manufacturing apparatus. It can damage the die coater. As a result, the quality and stability of the manufacturing process are reduced, and the product yield of the entire manufacturing process is also reduced. Therefore, it is important to detect foreign substances such as glass substrates in the flat display manufacturing process.

  In the proposals of Patent Documents 3 and 4 above, foreign matter on the surface of an object to be inspected, such as a glass substrate, can be detected, but foreign matter that adheres or exists between the back surface, that is, the object to be inspected and its work table. Detection is difficult. An object of the present invention is to detect foreign matters on the back surface of a glass substrate or the like, and as a result, the performance of the flat display is prevented from being impaired, and the foreign matters are also prevented from damaging the manufacturing apparatus. It is to improve the quality and stability of the manufacturing process, improve the product yield of the entire manufacturing process, and provide a flat display with stable quality.

  In general, in a resist coating process by a die coater method in manufacturing a flat display, a glass substrate is adsorbed on a work table having an adsorption function. In that case, when there is a foreign substance between the back side of the glass substrate, that is, between the glass substrate and the work table, the glass substrate has a property of gently bending so that the foreign substance part is raised.

  Therefore, when a laser light source placed on one end face irradiates the surface of a glass substrate or the like with a substantially parallel laser beam and the shape of the laser light is observed with a light receiver placed on the other end face, the glass substrate is flat. The phenomenon that the shape of the spot of the laser beam changes is observed in the case of the curved case and the case of the curved case. Therefore, by observing this phenomenon, it is possible to detect foreign matter on the back surface of the glass.

  In other words, means for solving the problem is to generate a laser beam that irradiates the work surface with a suction function on which the test object such as a glass substrate is mounted and the surface of the test object that is substantially parallel to the surface. A laser light source and a receiver that observes the spot shape, not just the brightness of the laser beam, are provided to detect foreign matter adhering to or existing on the back of the object to be inspected by the change in the spot shape of the laser beam. It is to be.

  As described above, the foreign matter detection method of the present invention can detect foreign matter adhering to or existing on the back surface of an object to be inspected, such as a glass substrate of a flat display, so that it can prevent impairing the performance of the flat display. Further, the foreign matter can be prevented from damaging the manufacturing apparatus, the quality and stability of the manufacturing process can be improved, and the product yield of the entire manufacturing process can be improved. As a result, the product yield of the entire manufacturing process can be improved, and a stable quality flat display can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

1 and 2, 1 is a glass substrate for forming a flat display, 2 is a laser light source, 3 is a light receiver for observing the spot shape of the laser light, and 4 is an adsorption function for placing the glass substrate by a die coater method. Indicates a workbench.
The light receiver 3 includes an image processing apparatus including a diffusion plate that forms an image of the spot shape of the laser beam and an area sensor such as a CCD that images the spot shape of the imaged laser beam.

  FIG. 2 is a cross-sectional view taken along the line AA ′ of FIG. 1. The work table 4 with a suction function is provided with several holes in a direction perpendicular to the glass substrate 1 and sucks air to suck the glass substrate 1. It is structured to be attracted to the attached work table 4.

  Further, the laser light source 2 is installed on one end surface of the glass substrate 1, and the laser light on the surface of the glass substrate is substantially parallel to the glass substrate toward the laser receiver 3 provided on the other end surface. It is the composition which irradiates. The spot shape of the laser light is approximately circular, approximately elliptical, approximately rectangular, etc., and has a size of approximately 1 mm to several mm.

  FIG. 2 shows a state where a foreign substance 10 exists between the back side of the glass substrate 1, that is, between the glass substrate and the work table, and the glass substrate 1 is adsorbed by the work table 4 with an adsorption function and is gently curved near the point 11. It is shown. Since the size of the foreign matter is assumed to be several tens of μm to several hundreds of μm, the size of the curvature of the glass substrate 1 is also several tens of μm to several hundreds of μm depending on the size of the foreign matter.

  When the laser beam is irradiated in this state, a part of the laser beam goes straight as it is, and the remaining part is reflected / refracted by the curvature of the glass substrate 1. As a result, the light receiver 3 forms an image different from the spot-shaped image formed by the laser beam in a state where there is no foreign matter.

FIG. 3 shows an outline of a laser beam spot-shaped image. FIG. 3A shows an image before deformation without foreign matter, and FIG. 3B shows an image after deformation due to foreign matter.
This is not the mere brightness level of the laser beam, but the spot shape change accompanied by the brightness level is observed with the light receiver 3 and image processing is performed, so that the foreign matter attached to or existing on the back side of the glass substrate 1 Can be detected.

Hereinafter, FIG. 4 shows a configuration example of the light receiver 3.
Reference numeral 38 denotes a diffusion plate that forms an image of the spot shape of the laser beam, 32 denotes a lens, 33 denotes a camera including an area sensor such as a CCD, and 30 denotes an image processing apparatus. An image filter 34, a CPU 35, a memory 36, and an output control unit 37 constitute an image processing apparatus 30.

  The laser light strikes the diffuser plate 38 and forms an image of the spot shape. The image is converted into an electrical signal by the camera 33 via the lens 32. The image processing device 30 performs image processing on the spot-shaped signal accompanied by the brightness level.

The image processing operation of the image processing apparatus 30 is as follows.
The spot-shaped signal is processed by the image filter 34 to remove noise. The CPU 35 determines the presence or absence of foreign matter by comparing the spot shape signal with the spot shape signal when there is no foreign matter already stored in the memory 36. When the CPU 35 determines that there is a foreign object, a signal such as an alarm is output from the output control unit 37.

  Moreover, although the said Example is description of the effect | action on the line which passes along one certain point of the glass substrate 1, it moves on the surface of the glass substrate 1 in the state where the arrangement relationship of the laser light source 2 and the light receiver 3 is maintained. Thus, foreign matter can be detected over the entire glass substrate 1. On the contrary, it is obvious that the same effect can be obtained even when the laser light source 2 and the light receiver 3 are fixed and the glass substrate 1 is moved in parallel.

  In the manufacturing process using the die coater, the laser light source 2 and the light receiver 3 are attached to the front portion of the die head of the die coater, and are moved in parallel with the die head, whereby foreign matter can be detected immediately before coating from the die head. The effect becomes more effective.

FIG. 5 is a cross-sectional view of an apparatus showing another embodiment of the present invention.
The same components as those in FIGS. 1 and 2 are denoted by the same reference numerals. Reference numerals 50 and 51 denote reflectors composed of mirrors, prisms and the like.

  In the description of the embodiment of FIGS. 1 and 2, the laser light source 2 and the light receiver 3 are installed at the end of the glass substrate 1, but in the embodiment of FIG. In addition, the light receiver 3 is installed, and the laser beams are bent by providing the reflectors 50 and 51. The reflectors 50 and 51 are placed on the surface of the glass substrate 1 so as to irradiate the laser beam substantially parallel to the glass substrate 1.

  Therefore, with this configuration, only the reflectors 50 and 51 may be installed at the end of the glass substrate 1, and the effects of the present invention can be applied to a manufacturing apparatus with a small installation space.

FIG. 6 is an external view of an apparatus showing another embodiment of the present invention.
The same components as those in FIGS. 1 and 2 are denoted by the same reference numerals. Reference numerals 21 and 31 denote additional laser light sources and light receivers, respectively.

  In the embodiment of FIGS. 1 and 2, one set of the laser light source 2 and the light receiver 3 is installed at the end of the glass substrate 1, but in the embodiment of FIG. 6, the laser light sources 2, 21 and the light receiver 3, Two sets of 31 are installed opposite to each other.

  In general, when a laser beam is reflected and refracted by the curvature of the glass substrate 1 to form an image on the diffusion plate 38 and observed, a larger change image is observed as the distance from the reflected and refracted point to the diffusion plate 38 is longer. it can. Conversely, when the distance from the reflected / refracted point to the diffuser plate 38 is short, it is difficult to observe the change image.

  Therefore, in the example of FIG. 6, a foreign substance that is present near the light receiver 3 and is difficult to detect with the light receiver 3 is installed with a laser light source 21 and a light receiver 31 so that the light receiver 31 can detect it. Similarly, the light receiver 3 can detect foreign substances that are present near the light receiver 31 and are difficult to detect with the light receiver 31.

  Thus, by installing two sets of the laser light source and the light receiver relative to each other, it becomes possible to detect where foreign matter adheres or exists on the glass substrate 1.

  FIG. 7 is a cross-sectional view of an apparatus showing a further embodiment.

  The same components as those in FIGS. 1 and 2 are denoted by the same reference numerals. Reference numerals 52, 53, and 54 denote laser beam reflectors, and 60 denotes a half mirror that reflects and transmits the laser beam.

  In Example 3, two sets of laser light sources and light receivers are provided opposite to each other to prevent a range in which it is difficult to detect foreign matter adhering to or existing on the back surface of the glass substrate 1. The same effect is obtained with one set of light source and light receiver.

  The operation will be described. First, the laser light source 2 is arranged so that the laser light is substantially parallel to the glass substrate 1 and irradiates the upper part from the surface of the glass substrate 1. Laser light emitted from the laser light source 2 is separated into downward light and straight light by the half mirror 60.

  First, the downward light is redirected by the reflector 54 and irradiates the surface of the glass substrate 1 substantially in parallel with the glass substrate 1. Thereafter, the reflector 53 changes the direction upward, and the reflector 52 reverses the laser light source 2. Then, the light is reflected by the half mirror 60 and imaged by the light receiver 3.

  On the other hand, the straight light at the half mirror 60 follows the reverse route. Irradiated from the laser light source 2, travels straight through the half mirror 60, changes the direction downward by the reflector 52, reflects by the reflector 53, and irradiates the surface substantially parallel to the glass substrate 1. Thereafter, the light is changed upward by the reflector 54, passes through the half mirror 60, and is imaged by the light receiver 3.

  As a result, it is possible to irradiate the left and right laser beams to the foreign material 10 attached to or existing on the back surface of the glass substrate 1. Therefore, in this embodiment, two sets of laser light sources and light receivers are provided opposite to each other, and the same effect as preventing the range in which the detection of the foreign material 10 is difficult can be obtained with one set of laser light sources and light receivers. , Laser light source and light receiver can be reduced and more economical.

  Moreover, in the said Example, the installation position of the laser light source 2 and the light receiver 3 assumes fixing on the position which irradiates a laser beam on the surface of the glass substrate 1 substantially in parallel with the glass substrate 1. FIG. However, the installation position of the laser light source 2 and the light receiver 3 is movable in the direction perpendicular to the glass substrate 1, and the thickness of the glass substrate 1 such as a liquid crystal display (LCD), plasma display (PDP), organic EL display is different. Even in the manufacturing process, by moving the installation position, it is possible to cope with the glass substrate 1 having a different thickness with one foreign object detection apparatus to which the present invention is applied.

  In the present invention, laser light is used to detect the foreign substance 10 on the back side of the glass substrate 1. However, if there is a foreign substance on the surface of the glass substrate 1, the laser light is diffused / scattered light by the foreign substance on the surface. Also occurs. Accordingly, by providing another light receiver that catches the diffused / scattered light on the upper portion of the glass substrate 1 as in the conventional example, foreign matter on the surface of the glass substrate 1 can also be detected.

  In other words, a single laser light source is provided, and a light receiver for observing the spot shape of the laser light and another light receiver for observing diffused / scattered light are provided on the front and back surfaces of the inspection object such as the glass substrate 1. Both adhered or existing foreign substances can be detected, and the effects of the conventional example and the effects of the present invention can be exhibited with one laser light source. In this case, the function of the other light receivers may be simply the brightness detection as in the conventional case, and the detection accuracy is further improved by the function of recognizing both the brightness and the shape similar to the light receiver of the present invention. .

It is an external view of the apparatus which shows embodiment of this invention. It is A-A 'sectional drawing in FIG. 1 of the apparatus. It is spot shape explanatory drawing of the laser beam in the light receiver of the apparatus. It is a figure which shows the structure of the light receiver of the apparatus. It is sectional drawing of the apparatus which shows another embodiment of this invention. It is an external view of the apparatus which shows other embodiment of this invention. FIG. 6 is a cross-sectional view of an apparatus showing a further embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Glass substrate 2, 21 Laser light source 3,31 Photoreceptor 4 Worktable with adsorption function 10 Foreign object 30 Image processing device 32 Lens 33 Camera 34 Image filter 35 CPU
36 Memory 37 Output Control Unit 38 Diffuser 50 to 54 Reflector 60 Half Mirror

Claims (4)

In the foreign matter detection method in the manufacturing process of a flat display having a coating process using a die coater,
A worktable with a suction function for mounting an object to be inspected for forming a flat display, a laser light source for generating laser light that irradiates the surface substantially parallel to the surface of the object to be inspected, and a spot shape of the laser light And detecting a foreign substance adhering to or existing on the back surface of the object to be inspected by a change in the spot shape of the laser beam,
A foreign matter detection method characterized by the above. In the foreign matter detection device in the flat display manufacturing process having a coating process using a die coater,
A workbench with a suction function for mounting an object to be inspected forming a flat display;
A laser light source that generates a laser beam that irradiates the surface substantially parallel to the surface of the object to be inspected;
A light receiver for observing the spot shape of the laser beam and detecting foreign matter adhering to or existing on the back surface of the object to be inspected by a change in the spot shape of the laser beam;
A foreign matter detection device comprising: A laser light source for generating the laser light;
A light receiver for observing the spot shape of the laser beam and detecting foreign matter adhering to or existing on the back surface of the object to be inspected by a change in the spot shape of the laser beam;
Other light receivers that are installed on the top of the inspection object by observing the diffused / scattered light of the laser beam generated on the surface of the inspection object, detecting foreign matter on the surface of the inspection object When,
The foreign object detection device according to claim 2, further comprising: In a flat display having a coating process using a die coater and a glass substrate on which a black matrix and RGB color filters are formed as a forming element,
A glass substrate inspected by the foreign matter inspection method of claim 1 in each step of a black matrix and an RGB color filter as a forming element.
A flat display characterized by that.