JPH1164160A - Apparatus for inspecting optical axis and method for inspecting optical axis using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus which can economically and easily be assembled and inspects optical axis of a phase difference plate at high precision. SOLUTION: A first standard polarization plate 2 whose optical axis 4 is paralleled to a standard line 6 and a second standard polarization plate 3 whose optical axis 5 is at right angles to the standard line are arranged in parallel on a light transmissive substrate 1 and further a third standard polarization plate 12 whose optical axis 13 is at 45 deg. to the standard line 6 is installed in a manner that the third polarization plate 12 can be overlapped on the first standard polarization plate 2 and the second standard polarization plate 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical axis inspection tool and an optical axis inspection method using the same.

[0002]

2. Description of the Related Art A retardation plate is useful as an optical element.
For example, it is used for a liquid crystal display device and the like. The direction of the optical axis (fast axis or slow axis) of such a phase difference plate is important, and it is necessary to confirm the direction of the optical axis when incorporating the phase difference plate into a liquid crystal display device. In particular, the phase difference plate incorporated in a recent liquid crystal display device requires precision of the optical axis, and even if the optical axis is slightly deviated, the intended performance of the liquid crystal display device cannot be secured. A good optical axis inspection method is needed.

Conventionally, as a method of inspecting the optical axis of a retardation plate, for example, a retardation plate to be inspected (hereinafter referred to as a retardation plate sample) is transmitted between two polarizing plates whose optical axes are orthogonal to each other. There is known a method of superimposing light amounts so as to be maximum or minimum. However, in order to detect a slight optical axis shift by such a method, the accuracy of the comparison of the amount of transmitted light visually is low. Therefore, the amount of transmitted light is usually compared using a photomultiplier tube. However, since the photomultiplier tube is expensive and requires complicated operations, it can be assembled cheaply and simply, and with high accuracy. It has been desired to develop an instrument capable of inspecting the optical axis of the phase difference plate.

[0004]

The inventors of the present invention have conducted intensive studies to develop an instrument that can be assembled easily and inexpensively and can accurately inspect an optical axis.
Two polarizing plates are arranged in parallel so that their optical axes are in a specific direction, and a retardation plate sample is placed between the two polarizing plates and a third polarizing plate having an optical axis in a specific direction. The present inventors have found that an optical axis inspection instrument configured to be able to be placed can inspect the optical axis of a retardation plate accurately and visually, and have reached the present invention.

[0005]

That is, according to the present invention, a first reference polarizing plate whose optical axis is parallel to a reference line is provided on a light transmitting plate and its optical axis is orthogonal to the reference line. The second reference polarizer is disposed, and the third reference polarizer is such that the optical axis thereof is oriented at 45 ° to the reference line when superimposed on the first reference polarizer and the second reference polarizer. And a first reference polarizing plate and a second reference polarizing plate.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. FIG. 1 shows an example of the optical axis inspection tool of the present invention. The light transmitting plate (1) may be a general synthetic resin plate such as an acrylic plate, a polycarbonate plate, a vinyl chloride plate, or a glass plate. The thickness of such a light transmitting plate is usually about 1 to 10 mm in terms of strength and easy handling, though it depends on the material. The light transmitting plate may be a transparent plate, but is preferably a light diffusing plate from the viewpoint of less fatigue in inspection. Examples of the light diffusion plate include a synthetic resin plate mixed with an inorganic filler such as silicon oxide and aluminum oxide, and a cloudy glass.
Further, the light transmitting plate may be colored with a pigment, a dye, or the like. At the time of inspection, the optical axis inspection instrument is usually illuminated from below with a backlight or the like. The backlight may be, for example, any of a fluorescent lamp, natural light, incandescent lamp, and the like.

[0007] A first reference polarizing plate (2) and a second reference polarizing plate (3) are arranged on the light transmitting plate (1). The first reference polarizer (2) and the second reference polarizer (3) are arranged in parallel on the light transmission plate (1), and are arranged so as not to substantially overlap each other. There may be overlapping portions within a range that does not hinder the inspection. The optical axis (4) of the first reference polarizer is parallel to the reference line (6), and the optical axis (5) of the second reference polarizer is orthogonal to the reference line (6). In order to dispose the first reference polarizing plate (2) and the second reference polarizing plate (3) on the light transmitting plate (1), they may be fixed using, for example, an adhesive or an adhesive. The first reference polarizer (2) and the second reference polarizer (3) may be arranged apart from each other, but if they are arranged adjacent to each other, a large polarizer sample as well as a small polarizer can be used. This is preferable because it can easily cope with sample inspection.

The direction of the reference line (6) is set to an arbitrary direction on the light transmitting plate (1), but is preferably in the front direction of the worker in practical use. It is preferable that the reference line is clearly indicated on the light transmitting plate so that the direction can be easily confirmed. As shown in FIG. 2, when the first reference polarizer (2) and the second reference polarizer (3) are arranged adjacent to each other along the reference line (6), the reference This is preferable because the line (6) can be easily recognized as the boundary line (7) between the two polarizing plates.

Further, the optical axis inspection tool of the present invention may be provided with a transparent protractor (9). As such a protractor, an acrylic protractor or the like is used. The angle center of the protractor (9) may be on the reference line (6),
It may be far from the reference line. By using such a protractor, the angle of the optical axis of the retarder sample (8) can be easily obtained.

The third reference polarizer (12) is provided so as to be superimposable on the first reference polarizer (2) and the second reference polarizer (3). In order to provide the third reference polarizing plate so as to be superimposable, it may be connected to the light transmitting plate (1) by, for example, a hinge. When the third reference polarizing plate is superimposed on the first reference polarizing plate and the second reference polarizing plate, the optical axis (13) is oriented at 45 ° with respect to the reference line (6).

In order to inspect the optical axis of a retardation plate sample using the optical axis inspection instrument of the present invention, for example, a first reference polarizing plate (2) and a second reference polarizing plate (3), and a third reference polarizing plate The retarder sample (8) is interposed between the retarder sample (8) and the plate (12), and the color tone of the portion (10) where the retarder sample and the third reference polarizer overlap the first reference polarizer is determined. The color tone of the portion (11) where the third reference polarizing plate overlaps with the second reference polarizing plate becomes achromatic, and the portion (10) where the retardation plate sample and the third reference polarizing plate overlap with the first reference polarizing plate. It is sufficient to mount the retardation plate sample and the third reference polarizer so that the brightness of the portion (11) where the second reference polarizer and the third reference polarizer overlap with each other is equal (FIG. 3).

When the first reference polarizing plate (2) and the second reference polarizing plate (3) are arranged adjacent to each other along the reference line (6), the retardation plate sample and the third reference polarizing plate are provided. Easily and accurately compares the color tone and brightness of the portion (10) where the first reference polarizing plate overlaps with the color tone and brightness of the portion (11) where the retarder sample and the third reference polarizing plate overlap the second reference polarizing plate. It is preferable because it is possible.

When the two portions (10, 11) become achromatic and have the same lightness, the optical axis of the retarder sample (8) is in the same direction as the reference line (6) or in a direction perpendicular to the reference line (6). . The direction of the optical axis can be easily determined by comparing the color tone when the retarder sample (8) is slightly rotated with a standard sample of the retarder prepared in advance. .

The angle of the optical axis of the polarizing plate sample (8) can be obtained, for example, by using a protractor (9) arranged in advance. Further, if a pin (14) is provided at the angle center of the protractor, the polarizing plate sample (8) can be placed with the pin (14) as a fulcrum, and the angle of the optical axis can be read as it is. It is preferable because it can also be performed.

[0015]

The optical axis inspection instrument of the present invention is inexpensively and easily assembled, and furthermore, the color tone and brightness of the portion where the phase difference plate sample and the third reference polarizing plate overlap with the first reference polarizing plate, and the phase difference plate Since the color tone and lightness of the portion where the sample and the third reference polarizing plate overlap with the second reference polarizing plate are compared, the optical axis of the phase difference plate can be inspected with sufficient accuracy even by visual inspection.

[0016]

EXAMPLES The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Example 1 The optical axis inspection tool shown in FIG. 1 was placed on a light box for photographic negative observation, and illuminated from the back. The first reference polarizer (2), the second reference polarizer (3), and the third reference polarizer (12) are superimposed, and the first reference polarizer, the second reference polarizer, and the third reference polarizer. The phase difference plate sample (8) [4.5 cm × 5 cm] is sandwiched between the phase difference plate sample and the third reference polarizing plate, and the color tone of the portion (10) where the phase difference plate sample and the third reference polarizing plate overlap with the first reference polarizing plate. The color tone of the portion (11) where the retarder sample and the third reference polarizer overlap with the second reference polarizer becomes achromatic, and the retarder sample and the third reference polarizer overlap with the first reference polarizer. The portion (10) was placed so that the brightness of the portion (11) where the phase difference plate sample and the third reference polarizing plate overlapped with the second reference polarizing plate were equal. The angle between one side [long side (5 cm)] (15) of the phase plate sample (8) and the reference line (6) at that time is read using a protractor, and this angle is read as the angle of the optical axis of the phase plate sample. (Θ). Table 1 shows the angles (θ) of the optical axes obtained for four different retarder samples (8).

Reference Example 1 Table 1 shows the results of measuring the angle of the optical axis of each retardation plate sample used in Example 1 using a polarizing microscope.

[0019]

Table 1 角度 Angle (θ) of optical axis of retarder sample Unit: ° 位相 Phase plate sample 1 2 3 4 ───────── ─────────────────────── Example 1 9.2 46.2 108.8 160.6 Reference Example 1 9.2 46.7 108.6 160.2 ────────────────────────────────

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of an optical axis inspection instrument of the present invention.

FIG. 2 is a schematic view showing an example of the optical axis inspection device of the present invention.

FIG. 3 is a schematic view illustrating an optical axis inspection method according to the present invention.

[Explanation of symbols]

1: light transmitting plate 2: first reference polarizing plate 3: second reference polarizing plate 4: optical axis of first reference polarizing plate 5: optical axis of second reference polarizing plate 6: reference line 7: first reference polarizing plate 8: Polarizer sample 9: Protractor 10: Portion where retarder sample and third reference polarizer overlap with first reference polarizer 11: Phase difference plate sample and third reference polarizer Part where the plate overlaps with the second reference polarizer 12: Third reference polarizer 13: Optical axis of third reference polarizer 14: Pin 15: One side (long side) of retardation plate sample θ: Optics of retardation plate sample Shaft angle [angle between one side (long side) of retardation plate sample and reference line]

Claims (4)

[Claims] 1. A first reference polarizer whose optical axis is parallel to a reference line and a second reference polarizer whose optical axis is orthogonal to the reference line are arranged on the light transmitting plate, And the third reference polarizing plate, the first reference polarizing plate and the second reference polarizing plate such that when the first reference polarizing plate and the second reference polarizing plate are superimposed on each other, the optical axis thereof is oriented at 45 ° to the reference line. An optical axis inspection instrument provided so as to be superimposable on a reference polarizing plate. 2. The optical axis inspection instrument according to claim 1, wherein the first reference polarizing plate and the second reference polarizing plate are adjacent to each other along a reference line. 3. A first reference polarizer whose optical axis is parallel to a reference line, a second reference polarizer whose optical axis is perpendicular to the reference line, and an optical axis thereof relative to the reference line. Is 45
Between the third reference polarizing plate in the direction of °, the phase difference plate sample, the color tone of the portion where the phase difference plate sample and the third reference polarizing plate overlap with the first reference polarizing plate, and the phase difference plate sample The color tone of the portion where the third reference polarizing plate and the second reference polarizing plate overlap each other is achromatic, and the lightness of the portion where the retardation plate sample and the third reference polarizing plate overlap the first reference polarizing plate, A method for inspecting an optical axis of a retardation plate, comprising placing the retardation plate sample and the third reference polarizing plate such that the brightness of a portion overlapping the second reference polarizing plate is equal. 4. The optical axis inspection method according to claim 3, wherein the first reference polarizing plate and the second reference polarizing plate are arranged adjacent to each other along a reference line.