JPH10206280A - Inspecting device for transparent substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device facilitating inspection of a transparent electrode formed on a transparent substrate or of the transparent substrate itself. SOLUTION: For the purpose of inspecting the quality of a transparent electrode 12 formed on the surface of a glass substrate 10 by the naked eye, this device is equipped with an optical waveguide 20 whereby light containing a prescribed wavelength enters from one side of the glass substrate 10, a reflecting member 30 which reflects the light on the opposite side, a light source 40 and a reflector 42. Herein the light enters the glass substrate 10 from the optical waveguide 20 and advancing inside the substrate, being reflected repeatedly between the surfaces of the glass substrate 10, is scattered by the surface of the transparent electrode 12 not being smooth, and therefore the shape of the transparent electrode 12, i.e., the quality thereof, can be judged by observing a flat surface part of the glass substrate 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent substrate used for an LCD (Liquid Crystal Display), a touch panel or the like and a transparent substrate inspection apparatus for inspecting the quality of a transparent electrode formed on the substrate.

[0002]

2. Description of the Related Art In an LCD, a liquid crystal material is sandwiched between two transparent substrates (glass substrates), and a predetermined driving voltage is applied to a transparent electrode formed on the surface of the transparent substrate to change the alignment direction of liquid crystal molecules. Thus, a predetermined display is performed.
For example, non-alkali glass or soda lime glass is used as the transparent substrate, and an ITO (indium tin oxide) film, which is a transparent conductive film, is used as the transparent electrode.

[0003]

The above-mentioned transparent electrode formed on the surface of the transparent substrate is required to have a high transparency so as not to block the light of the backlight. Also, it was not easy to inspect the quality of each transparent electrode. For example, when a display screen of about 10 inches is considered, the number of pixels constituting the display surface reaches tens of thousands of pixels, so that the number of transparent electrodes formed corresponding to each pixel is enormous and minute, It is difficult to determine the quality of each transparent electrode. For this reason, conventionally, the inspection was performed by relying on the intuition of a skilled worker, and the quality of the transparent electrode was also inspected at the time of product inspection after the LCD was completed. However, when performing inspections based on the intuition of a skilled worker, the number of workers who can perform inspections is limited, so that improvement in working efficiency cannot be expected.In the worst case, the inspection process stops due to the worker resting. It will also be. In addition, when the inspection is performed after the LCD is completed, since the transparent electrode on the transparent substrate is defective, the LC completed through the subsequent manufacturing process is not used.
Since the whole D becomes a defective product, there is much waste, and a method for efficiently performing the inspection immediately after forming the transparent electrode is desired.

In the above, the difficulty in inspecting a transparent electrode formed on a transparent substrate has been described. The same can be said for the case of inspecting a transparent substrate itself. That is, in the inspection of the transparent substrate, when it is attempted to find a scratch or a step formed on the surface of the transparent substrate or a bubble formed inside the transparent substrate, both the transparent substrate and the scratch or the bubble are transparent. Therefore, it is not easy to visually inspect.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a transparent substrate inspection apparatus which can easily inspect a transparent electrode formed on a transparent substrate or the transparent substrate itself. It is in.

[0006]

In order to solve the above-mentioned problems, a transparent substrate inspection apparatus according to the present invention has a light incident portion for receiving light having a predetermined wavelength from the side of the transparent substrate. By observing the flat part of the transparent substrate with light incident on the inside of the transparent substrate from this light incident part, scratches and steps on the surface of the transparent substrate formed on the surface of the transparent substrate, steps on the surface of the transparent substrate, bubbles inside the transparent substrate, etc. Since it can be clearly recognized, the inspection of the transparent substrate becomes easy.

It is preferable that the light incident on the transparent electrode from the above-described light incident portion includes a visible region, particularly a wavelength near a peak of visibility, and in this case, the quality of the transparent substrate is visually checked by an operator. You can find out.

[0008] Specifically, the above-mentioned light incident portion includes a light source for emitting light having a predetermined wavelength, a condensing portion for condensing radial light emitted from the light source, and a light condensing portion. The optical waveguide includes an incident surface on which light condensed at one point is incident and a linear exit surface narrower than the width of the incident side surface of the transparent substrate. By condensing the light from the light source and passing it through the optical waveguide, light can be efficiently incident on the transparent substrate from the linear exit surface of the optical waveguide,
Since light leaking along the surface of the transparent substrate can be eliminated, it is possible to prevent the light from being scattered by dust or the like adhering to the surface of the transparent substrate and making the above-described transparent electrode or the like difficult to see.

When a light reflecting portion is provided on the side surface of the transparent substrate opposite to the light incident portion, light incident from the light incident portion and traveling inside the transparent substrate is reflected by the light reflecting portion. Is reflected by the part and goes back toward the light incident part,
Since the light intensity when observing the plane portion of the transparent substrate becomes uniform over the entire area of the plane portion, the inspection of the transparent substrate is further facilitated.

Specifically, the above-mentioned light reflecting portion has an incident surface substantially coincident with the emission side surface of the transparent substrate, and a reflecting surface for reflecting light incident through the incident surface.
Light traveling inside the transparent substrate can be reflected without leaking to the outside of the transparent substrate.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A transparent substrate inspection apparatus to which the present invention is applied inspects a glass substrate as a transparent substrate having a transparent electrode formed on the surface or a glass substrate itself having no surface formed thereon. The method is characterized in that the quality of the transparent electrode formed on the surface of the glass substrate and the quality of the glass substrate itself are determined by irradiating light into the inside of the glass substrate from the side direction. Hereinafter, a transparent substrate inspection apparatus according to an embodiment will be described with reference to the drawings.

FIG. 1 is a perspective view showing the structure of a transparent substrate inspection apparatus according to an embodiment of the present invention. FIG.
FIG. 2 is an enlarged view of the transparent substrate inspection apparatus shown in FIG. 1 as viewed from a side.

The apparatus for inspecting a transparent substrate according to the present embodiment shown in these figures uses a glass substrate 10 for LCD having a transparent electrode 12 formed on its surface as a member to be inspected, and inspects the quality of the transparent electrode 12 with the naked eye. In order to achieve this, an optical waveguide 20 on which light having a predetermined wavelength is incident from one side surface of the glass substrate 10 and light incident on the glass substrate 10 from the optical waveguide 20 is reflected on the opposite side surface of the glass substrate 10 Reflecting member 30, a light source 40 for generating light incident on one end of the optical waveguide 20, and a reflection as a condensing portion for condensing light emitted radially from the light source 40 on one end of the optical waveguide 20. And a plate 42.

As described above, the glass substrate 10 is an LCD.
For example, a transparent electrode film I is formed on the surface of alkali-free glass or soda lime glass.
A TO (indium tin oxide) film is formed as the transparent electrode 12. The shape of each transparent electrode 12 differs depending on whether the LCD is driven by a simple matrix method or an active matrix method, and furthermore, which method is used.

The optical waveguide 20 emits light that has been condensed and incident at substantially one point from a linear exit surface,
This is for allowing light to enter the inside of the glass substrate 10 from the side direction.

FIG. 3 is a diagram showing the shape of the extracted optical waveguide 20. FIG. 3A is a plan view, and FIG. 3B is a side view. As shown in these figures, an optical waveguide 20 has an incident surface 22 for receiving light condensed substantially at one point, and an output surface for emitting light traveling in the inside linearly with almost uniform intensity. And a surface 24. For example, it is formed by deforming an optical fiber having a predetermined length, and while using one end surface as the incident surface 22, the thickness is reduced toward the other end, and the width is expanded so as to increase, The leading end forms a linear emission surface 24. The light condensed and incident on the incident surface 22 is propagated while repeating almost total reflection on the surface of the optical waveguide 20, and light having a substantially uniform intensity distribution is emitted from the linear emission surface 24.

The thickness of the light exit surface 24 of the optical waveguide 20 is set smaller than the thickness of the glass substrate 10, and the light exit surface 24 is disposed in close contact with one side surface of the glass substrate 10. Therefore, the exit surface 2 of the optical waveguide 20
The light emitted from 4 hardly leaks out,
The light enters the inside of the glass substrate 10.

The reflecting member 30 is for totally reflecting the light traveling inside the glass substrate 10,
The side surface of the glass substrate 10 is arranged in close contact with the side opposite to the installation position of the optical waveguide 20. As shown in FIG. 2, the reflection member 30 is formed by a transparent member 32 installed so as to be partially in close contact with the side surface of the glass substrate 10, and the close contact portion is an incident surface. A reflection film 34 as a reflection surface is formed on the outer peripheral surface of the transparent member 32 except for the above. As described above, the reflecting member 30 is
4 forms a closed space, and light that enters the reflection member 30 from the glass substrate 10 side is transmitted by the transparent member 3.
After proceeding through the inside 2, the light is almost totally reflected by the reflection film 34, and is incident on the glass substrate 10 again.

FIG. 4 is a diagram showing an intensity distribution of light traveling in the glass substrate 10. The incident position shown in the figure corresponds to the side position of the glass substrate 10 on the optical waveguide 20 side.
The reflection position corresponds to the position of the side surface of the glass substrate 10 on the reflection member 30 side. The light incident on the inside of the glass substrate 10 from the optical waveguide 20 travels inside the glass substrate 10 while repeating reflection on the surface of the glass substrate 10. However, since a small amount of light is transmitted through the surface, the characteristic A shown in FIG. As shown in
The light intensity decreases as the light travels through the glass substrate 10. This tendency is the same for the light reflected by the reflection member 30, and as shown by the characteristic B in FIG. 4, the light is reflected by the reflection member 30 at the reflection position, which is the other side surface of the glass substrate 10. As the light travels backward, the light intensity decreases.

As described above, since the light traveling from the incident position to the reflection position and the light traveling backward from the reflection position to the incident position gradually decrease in intensity, the entire glass substrate 10 is substantially uniform. Light intensity.

The transparent substrate inspection apparatus of the present embodiment has such a configuration. Next, an outline of the case where the glass substrate 10 is inspected using this transparent substrate inspection apparatus will be described.
FIG. 5 is a diagram showing a state of reflection and transmission of light on the surfaces of the glass substrate 10 and the transparent electrode 12.

As shown in FIG. 1, in the portion where the transparent electrode 12 is not formed, the light traveling in the glass substrate 10 is substantially different on the surface of the glass substrate 10 because the refractive index of air is different from that of the glass substrate 10. Although it is totally reflected, part of it is transmitted through the air. On the other hand, since the refractive index of the transparent electrode 12 is not so small as that of air,
In the portion where is formed, part of the light traveling in the glass substrate 10 is transmitted through the transparent electrode 12 and
However, since the surface of the transparent electrode 12 is generally uneven and not smooth, the light reaching the surface tends to be scattered by the uneven portion of the surface.

Therefore, the intensity of light transmitted from the glass substrate 10 or the like into the air differs depending on the presence or absence of the transparent electrode 12, and when the flat portion of the glass substrate 10 is observed, the shape of the transparent electrode 12 is visually observed. It can be clearly confirmed.

By the way, as described above, the glass substrate 10
In order to visually observe the planar portion of the optical waveguide 20, a wavelength of 400 to 750 nm
It is necessary to enter light including a visible region of a certain degree. Preferably, light including a wavelength near 550 nm at which luminosity is maximized is incident.

FIG. 6 is a diagram showing the relationship between the wavelength of light and the visibility when a tungsten lamp is used as the light source 40. As shown in FIG.
Has a peak near 1000 nm and is 400 to 75
It contains a peak in the visible region of about 0 nm, especially the luminosity D near 550 nm.
Allows the operator to visually inspect the shape of the transparent electrode 12 formed on the surface of the glass substrate 10, that is, the quality of the transparent electrode 12.

In the above-described embodiment, the quality of the transparent electrode 12 formed on the surface is inspected by irradiating light into the glass substrate 10. Alternatively, the glass substrate 10 itself can be inspected by detecting a scratch or a step on the surface of the glass substrate 10.

FIG. 7 is a perspective view showing the configuration of a transparent substrate inspection apparatus in which a member to be inspected is a glass substrate itself. The transparent substrate inspection device shown in FIG. 7 is the same as the transparent substrate inspection device shown in FIG. 1 except that the inspected member is the glass substrate 10a itself, and the optical waveguide 20, the reflecting member 30, the light source 40, and the A plate 42 is provided.

As shown in FIG. 8, if there is a flaw 50 or a step 52 on the surface of the glass substrate 10a, the light enters from the optical waveguide 20 and travels in the glass substrate 10a, or is reflected by the reflecting member 30 and is reflected by the glass. Light traveling backward in the substrate 10a is scattered by a scratch 50 or a step 52 on the surface of the glass substrate 10a. Therefore, by observing the portion where the light is scattered on the flat portion of the glass 10a, the scratch 50 and the step 52 are observed.
Can be found visually.

Further, as shown in FIG.
The same applies to the case where bubbles 54 and foreign substances 56 are present inside a. Light traveling in or backward in the glass substrate 10a is scattered by these bubbles 54 and foreign substances 56. Therefore,
By observing the flat portion of the glass substrate 10a and observing the portion where the light is scattered, the bubbles 54 and the foreign matter 56 can be found visually.

As described above, as shown in FIG. 7, the light enters the inside of the glass substrate 1 from the optical waveguide 20.
Flaw 50 formed on the surface or inside of 0a itself,
Defects such as the step 52, the bubble 54, and the foreign matter 56 can be found by visual inspection of an operator. FIG.
As shown in FIG. 7 and FIG. 7, the inspection of the glass substrate 10 having the transparent electrode 12 formed on the surface and the inspection of the glass substrate 10a having nothing formed on the surface can be performed by the same inspection apparatus. There is also an advantage that it can be shared.

The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the present invention. For example, the transparent substrate inspection apparatus of the above-described embodiment uses the glass substrate 10 or 1 as the inspection target member.
Light is incident on one side of the glass substrate 10a, and the light traveling inside the glass substrate 10 or the like is reflected by the reflecting member 30 closely attached to the opposite side, but the reflecting member 30 is removed. You may. In this case, FIG.
As shown in the characteristic A, since the intensity of the light traveling from the incident position of the glass substrates 10 and 10a gradually decreases, the light becomes darker as the distance from the incident position increases. Since the light is still scattered by the flaw 50 or the like or the bubble 54 or the like inside, the light can be found by visual inspection.

As shown in FIGS. 9A and 9B,
Instead of the reflecting member 30, an optical waveguide 20A having the same shape as that of the optical waveguide 20 is arranged, and light is incident on the optical waveguide 20A so that the glass substrate 1 serving as a member to be inspected is provided.
Light may enter the inside of the glass substrate 10 or the like from both of the two opposing side surfaces 0 or 10a.
In this case, the intensity of light incident on the inside of the glass substrate 10 or the like increases, and the intensity of light becomes almost constant over the entire surface of the glass substrate 10 or the like. Become.

In the above-described embodiment, the case where the glass substrate 10 used for the LCD is inspected is described as an example. However, the glass substrate used for an application other than the LCD may be inspected. For example, the present invention can be applied to a case of inspecting a transparent electrode on a surface of a touch panel, which is placed on a display screen. In addition, the present invention is not limited to the glass substrate 10, and a transparent electrode formed on the surface of a transparent substrate made of a resin material or the like, or the transparent substrate itself may be inspected.

The above-described transparent substrate inspection apparatus inspects the transparent electrode 12 formed on the surface of the glass substrate 10 and the flaw 50 of the glass substrate 10a itself by visual inspection of an operator. The whole of the plane portions 10 and 10a may be photographed by a camera, and the result may be subjected to image processing to automate the inspection. For example, the shape of the transparent electrode 12 formed on the surface of the glass substrate 10 is determined by performing a differentiation process on the captured image and comparing the result with a predetermined threshold value. When photographing with a camera in this way, it is not necessary to use light having a wavelength in the visible region including the peak of visibility, and the wavelength of light to be used is set in consideration of the sensitivity of the image receiving element of the camera. do it.

In the above-described embodiment, as shown in FIG.
Although the case where the thickness is smaller than the thicknesses 0 and 10a has been described, it is sufficient that the light emitted from the optical waveguide 20 does not leak to the surface of the glass substrate 10 or the like. Good.

Further, as an example, the shape of the reflecting member 30 is made as shown in FIG. 2. However, since it is sufficient that the light traveling inside the glass substrate 10 or the like can be reflected (preferably total reflection), other members are used. It may be formed in a shape. For example, a flat mirror having a mirror-finished surface is placed in close contact with the glass substrate 1.
Light that travels inside 0 or the like may be reflected.

[0037]

As described above, according to the present invention, the transparent electrode formed on the surface of the transparent substrate can be observed by observing the plane portion of the transparent substrate in a state where light enters the transparent substrate from the light incident portion. The transparent substrate can be easily inspected because scratches and steps on the surface of the transparent substrate or bubbles inside the transparent substrate can be clearly recognized. In particular, the light incident on the transparent substrate preferably includes a visible region, particularly a wavelength near the peak of visibility, and in this case, the inspection result can be easily confirmed by an operator.

When a light reflecting portion is provided on the side surface of the transparent substrate opposite to the light incident portion, light incident from the light incident portion and traveling inside the transparent substrate is reflected by the light reflecting portion. Is reflected by the part and goes back toward the light incident part,
Since the light intensity when observing the plane portion of the transparent substrate becomes uniform over the entire area of the plane portion, the inspection of the transparent substrate is further facilitated.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating a configuration of a transparent substrate inspection apparatus according to an embodiment.

FIG. 2 is an enlarged view of the transparent substrate inspection apparatus shown in FIG. 1 as viewed from a side.

FIG. 3 is a diagram illustrating a shape of an extracted optical waveguide.

FIG. 4 is a diagram showing the intensity of light traveling in a glass substrate.

FIG. 5 is a diagram showing a state of light traveling in a glass substrate.

FIG. 6 is a diagram showing the relationship between luminous energy and luminous energy of a tungsten lamp.

FIG. 7 is an explanatory diagram in a case where the transparent substrate inspection apparatus shown in FIG. 1 inspects the glass substrate itself for defects.

FIG. 8 is an enlarged view of the transparent substrate inspection apparatus shown in FIG. 7 as viewed from a side.

FIG. 9 is a view showing a modification of the transparent substrate inspection apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Glass substrate 12 Transparent electrode 20 Optical waveguide 30 Reflecting member 40 Light source 42 Reflector

Claims (7)

[Claims] 1. A state in which light having a predetermined wavelength is incident from a side surface direction of a flat transparent substrate having a flat surface portion opposed thereto, and light is incident on the inside of the transparent substrate by the light incident portion. A transparent substrate inspection apparatus for inspecting the transparent substrate by observing the flat portion. 2. A light incident portion for receiving light containing a predetermined wavelength from a side surface direction of a flat transparent substrate having an opposing flat surface portion having a transparent electrode formed on at least one surface,
A transparent substrate inspection apparatus, wherein the inspection of the transparent electrode formed on the transparent substrate is performed by observing the plane portion in a state where light enters the inside of the transparent substrate by the light incident portion. 3. The transparent substrate inspection apparatus according to claim 1, wherein the light incident on the transparent substrate from the light incident portion includes a visible region. 4. The transparent substrate inspection apparatus according to claim 1, wherein light incident on the transparent substrate from the light incident portion includes a wavelength near a peak of visibility. 5. The light source according to claim 1, wherein the light incident unit emits light having a predetermined wavelength,
A condensing portion for condensing radial light emitted from the light source, a light incident surface on which light condensed substantially at one point by the light condensing portion is narrower than a width of an incident side surface of the transparent substrate. An optical waveguide having a linear emission surface and a transparent substrate inspection apparatus. 6. The transparent substrate according to claim 1, further comprising: a light reflecting portion on a side surface of the transparent substrate facing the light incident portion, wherein the light reflecting portion receives light from the light incident portion and illuminates the inside of the transparent substrate. A transparent substrate inspection apparatus, which reflects light that travels and reaches the light reflection part. 7. The light-reflecting unit according to claim 6, wherein the light-reflecting portion includes an incident surface substantially coinciding with an emission-side side surface of the transparent substrate, and a reflecting surface for reflecting light incident through the incident surface. Transparent substrate inspection equipment.