JPH02116703A - Apparatus for inspecting circuit pattern on glass substrate - Google Patents

Abstract

PURPOSE:To inspect the position and shape of a circuit pattern highly precisely by applying a light at a Brewster angle to a substance to be inspected which is positioned in a positioning element and by observing the same by a camera. CONSTITUTION:A liquid crystal display body 20 is placed on an X table 17 and a light source 6 is lighted. Then a light emitted from the light source 6 is reflected on the upper surface of the liquid crystal display body 20 and the reflected light enters a camera 5. The light source 6 and the camera 5 are provided at Brewster angles thetaI and thetaR to the surface of observation of the liquid crystal display body 20 and, besides, polarizers 9 and 10 transmitting only a light oscillating in the direction intersecting the incident plane perpendicularly are provided in front of them respectively. Since a glass substrate 21 and an ITO electrode 23 have different reflectivities RP at the Brewster angle from each other, it is possible to observe the pattern of the ITO electrode 23 distinctly and to judge the appropriateness of the shape, position, etc., thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an apparatus for inspecting circuit patterns on a glass substrate.

(Prior art) Transparent ITO formed on a glass substrate such as a liquid crystal display
As an inspection device for circuit patterns such as electrodes, there is a known device that utilizes the difference in infrared light transmittance between a glass substrate and an ITO electrode (Japanese Unexamined Patent Publication No. 188896/1989).

In this device, an infrared light source is provided above a substrate on which a plurality of striped ITO electrodes are formed, and an infrared light line sensor is provided below the substrate to detect infrared light transmitted through the ITO electrodes. , from the output value of this line sensor, I
This is to inspect the TO electrode pattern.

(Problems to be Solved by the Invention) The conventional device described above detects an ITo electrode by using the difference in transmittance of infrared light that passes through the glass substrate and the ITO electrode. The transmittance of the ITO electrode is slightly higher than that of the glass substrate, and there is no large difference in 5ift ratio between the two, so there is a problem that it is difficult to clearly detect the pattern position, shape, etc. of the ITO electrode.

By the way, glass made of SiO□ and IT0 (InT
In○2), metallic materials such as gold, copper, and aluminum have significant differences in reflectance characteristics with respect to polarized light vibrating in a direction parallel to the plane of incidence. That is, in general,
The Brewster angle for polarized light as described above is smaller for glass than for metallic substances, and the reflectance of glass at the Brewster angle is much smaller than that for metallic substances.

Therefore, by utilizing the difference in the reflectance characteristics of glass and metal for polarized light, it is possible to accurately inspect a circuit pattern made of metal such as an ITO electrode formed on a glass substrate.

Therefore, an object of the present invention is to provide an apparatus that can accurately inspect a circuit pattern formed on a glass substrate by utilizing the optical characteristics as described above.

(Means for Solving the Problems) For this purpose, the present invention provides a positioning section for positioning an object to be inspected, which is formed by forming a circuit pattern made of a metal substance on a glass substrate, and a light source for irradiating the object to be inspected with light. , a camera that observes the reflected light, a polarizer disposed in the optical path of the light, and the light source and camera that are aligned at the Brewster angle with respect to the observation surface of the object to be inspected, in the XY force direction. An inspection device for a circuit pattern formed on a glass substrate is constructed from a moving device for relatively moving the device.

(Function) In the above configuration, the object to be inspected positioned in the positioning section is irradiated with light at the Brewster's angle and observed with a camera, thereby changing the polarization of the glass substrate and circuit pattern observed through the polarizer. Since the reflectance characteristics are different, the position, shape, etc. of the circuit pattern can be inspected with high precision.

(Example) Hereinafter, the present invention will be described in detail with reference to the drawings, taking as an example a liquid crystal display body in which ITO electrodes are formed on a glass substrate as an object to be inspected.

FIG. 1 is an overall side view of an ITO electrode inspection device,
Reference numeral 1 denotes a Y-direction moving device, which is composed of a Y-table 2 and a supporting section 3 erected thereon, and the supporting section 3 is moved in the Y-direction by a driving means such as a motor. An arm portion 4 extending laterally is provided at the upper portion of the support portion 3, and a camera 5 and a light source 6 are provided at the lower portion of the arm portion 4.

Reference numerals 7 and 8 denote frames to which the camera 5 and light source 6 are attached, and polarizers 9 and 10 are erected in front of the camera 5 and the light source 6. As shown in the figure, the camera 5 and the light source 6 are arranged to be tilted forward (see also FIG. 2), and the light emitted from the light source 6 is directed toward the observation surface of the liquid crystal display 20 as the object to be inspected. The light enters the camera 5 at the Brewster angle θl, and is reflected by this and enters the camera 5 at the same angle θR.

Reference numeral 15 denotes an X-direction moving device disposed below the camera and light source 6, and is constructed by disposing an X-table 17 on which a liquid crystal display 20 is placed on a base 16. By driving the moving device 1 and the X-direction moving device 15,
The camera 5 and light source 6 move relative to the upper surface of the liquid crystal display 20, that is, the viewing surface, in the XY force directions while maintaining the Brewster angles θI and θR with respect to the viewing surface.

FIG. 4 shows a liquid crystal display 20, which is formed by sealing liquid crystal inside two upper and lower glass substrates 21 and 22. On the inner surface of the glass substrate 21, a transparent circuit pattern is formed. An ITO electrode 23 is formed.

Figure 3 shows a glass substrate (SiO□) and an ITO electrode (InT
inOt), where the horizontal axis is the incident angle θ and the vertical axis is the reflectance RP. The reflectance RP is the ratio of the amplitude of the light that vibrates in a direction parallel to the plane of incidence among the light that enters the liquid crystal display 20 and the amplitude of the light that is reflected and vibrates in the same direction, By installing the polarizer 10 in front of the camera 5 and the light source 6, only light in the same direction is allowed to enter the liquid crystal display 20, and this can be observed by the camera 5.

As shown in the figure, as the incident angle θ gradually increases (becomes larger), a difference begins to appear in the reflectance RP between the glass substrate 21 and the ITO electrode 23, and the incident angle θ becomes 56'(Brewster's angle θI
), the reflectance RP of the glass substrate 21 becomes almost zero, and there is a significant difference between the reflectance RP of the ITO electrode 23 and the position and shape of the ITO electrode 23 by utilizing the difference in reflectance. can be clearly observed. As is clear from the figure, there is a large difference in reflectance RP between the glass substrate and the +TO electrode not only at the exact Brewster angle, but also near the Brewster angle. Therefore, in the present invention, the Brewster's angle includes not only the exact Brewster's angle (56° in this example as described above) but also approximately the Brewster's angle.

This device has the above-mentioned configuration, and the inspection work will be explained next.

When the liquid crystal display 20 is placed on the X table 17 and the light source 6 is turned on, the light emitted from the light source 6 is reflected on the upper surface of the liquid crystal display 20, and the reflected light enters the camera 5. The light source 6 and the camera 5 are arranged at Brewster's angles θ■ and θR with respect to the observation surface, that is, the upper surface, of the liquid crystal display 20, and in front of each of them, light vibrating in a direction perpendicular to the incident surface is provided. Since a polarizer 9.10 is provided that allows only the third
As explained with reference to the figure, the glass substrate 21 and I
Since the reflectance RP of the TO electrode 23 at the Brewster angle is different, the pattern of the ITO electrode 23 can be clearly observed and the quality of its shape, position, etc. can be judged.

Incidentally, an object to be inspected such as a liquid crystal display generally has a considerable size, and therefore, when inspecting it, it is divided into a plurality of blocks and inspected. FIG. 5 shows this situation, in which the viewing surface of the liquid crystal display 20 is divided into a plurality of blocks a% d, the X-direction moving device 15 and the Y-direction moving device 1 are driven, and the camera 5 The light source 6 is moved in the XY force direction relative to the observation surface while maintaining the Brewster angle, and each block is inspected. Note that in this embodiment, the liquid crystal display body 20 is
The camera 5 and the light source 6 are moved in the Y direction, but the point is that they only need to be relatively moved in the XY direction. Therefore, for example, if the camera 5 and the light source 6 are fixed, The liquid crystal display 20 is an XY child table! ! Put it down,
It may be moved in the XY force directions. In addition, the circuit pattern formed on the glass substrate is not limited to ITO electrodes, but also gold electrodes.

It may also be a circuit pattern made of a metal material such as copper.

(Effects of the Invention) As explained above, the inspection device for a circuit pattern on a glass substrate according to the present invention includes a positioning section for positioning an object to be inspected, which is formed by forming a circuit pattern made of a metal substance on a glass substrate; A light source that irradiates light onto the object to be inspected, a camera that observes the reflected light, a polarizer disposed in the optical path of the light, and a Brewster beam that connects the light source and camera to the observation surface of the object to be inspected. Since it is comprised of a moving device that holds the corner and relatively moves it in the XY force directions, circuit patterns such as ITO electrodes formed on a glass substrate can be inspected simply and accurately.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which Fig. 1 is a side view of a circuit pattern inspection device, Fig. 2 is a partial side view, Fig. 3 is an optical characteristic diagram, and Fig. 4 is a liquid crystal display. Perspective view of 5th
The figure is a plan view during inspection. 1.15...Movement device 5...Camera 6...Light source 9.10...Polarizer 20...Liquid crystal display as inspection object 21.22...
・Glass substrate ・ITO electrode as circuit pattern

Claims (1)

[Claims] A positioning unit that positions an object to be inspected, which is made by forming a circuit pattern made of a metal substance on a glass substrate, a light source that irradiates the object with light, a camera that observes the reflected light, and a camera that is arranged in the optical path of the light. A glass comprising: a polarizer provided thereon; and a moving device that moves the light source and camera relatively in the X and Y directions while maintaining the Brewster angle with respect to the observation surface of the object to be inspected. Inspection device for circuit patterns on boards.