JPS60231105A - Measurement of shift of absorbing axis - Google Patents

Abstract

PURPOSE:To facilitate the measurement of the shift of an absorbing axis, by calculating the angle reaching a point where the intensity of transmitted light becomes min while the specimen to be measured placed between two polarizers forming a Nicol optical system is rotated around the axis of the optical system. CONSTITUTION:An orthogonal Nicol optical system is constituted of a light source 1, two polarizers 3a, 3b arranged so that absorbing axes mutually cross at right angles and a light receiver 4. A specimen 2 to be measured is held between both polarizers 3a, 3b by a holder 5 so that the surface thereof crosses the X-axis of the orthogonal Nicol optical system at right angles. Transmitted light is detected by the light receiver 4 while the specimen 2 is rotated around the axis X and recorded by a recorder 6. By this mechanism, the relation of the intensity and rotary angle of transmitted light is displayed by the recorder 6 and the shift angle of the absorbing angle of the specimen 2 to be measured can be calculated instantaneously.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for measuring absorption axis deviation, and more particularly to a method for measuring the absorption axis deviation angle at each position of various polarizing plates.

<Prior Art> Various polarizing plates are essential for display devices, especially display devices using liquid crystals. However, for this purpose,
If the absorption axis of the polarizing plate is misaligned, the visible light transmittance will deviate from the standard range. Further, when assembled as a cell as it is, problems such as uneven coloring occur.

<Problems to be Solved by the Invention> Therefore, various methods have been studied to measure the deviation angle of the absorption axes of various polarizing plates, but no reliable method has yet been found.

An object of the present invention is to provide a method that can measure the deviation angle of the absorption axis at each position of various polarizing plates.

Means for Solving the Problems> The present invention uses an orthogonal Nicol optical system in which a light source, two polarizers, and a light receiver are arranged in a uniaxial direction, so that a sample to be measured placed between the two polarizers is While rotating around the axis of the Nikol optical system, the transmitted light intensity is measured, and the deviation of the absorption axis of the sample to be measured is measured by measuring the rotation angle to the rotational position where the transmitted light intensity is the lowest. ing.

<Example> The figure is a perspective view of an apparatus for carrying out the method of the invention.

A light source 1 and a light source 2 arranged so that their absorption axes are orthogonal to each other.
The polarizers 3a, 3b and the light receiver 4 constitute an orthogonal Nicol optical system. A chip-shaped sample to be measured 2 is placed between the photons 3a and 3b on both sides, with its surface facing the axis X of the orthogonal Nicol optical system.
Insert it so that it is perpendicular to the
The transmitted light at each rotational position is captured by the light receiver 4, and the transmitted light intensity is measured. 5 is a sample holder. The transmitted light intensity can be recorded with a pen on the recorder 6. In this case, paper 6a
The moving speed is made to correspond in advance to the rotational angular velocity of the sample to be measured 2.

The measurement of the deviation angle y of the absorption axis of the sample to be measured 2 will be explained.

Now, when the sample 2 to be measured is inserted between the polarizer 3a and the polarizer 3b, parallel light is irradiated from the light source 1, and the transmitted light is picked up by the receiver 4, the intensity of the transmitted light is I = = A2ein2 (
2, g) −Elin” (J / 2) where δ=2
π·Δn−d/λ A: Constant 0: Absorption axis deviation angle Δn: Refractive index difference d: Thickness of the sample to be measured λ: Represented by the wavelength of the light source.

Here, Δn, d, and λ do not change if the same device is used and the same sample is used, and therefore the value of 5in2 (δ/2) is constant. Therefore, the transmitted light intensity is a function only of the deviation angle y of the absorption axis. That is, Ebe: 5in2 (20).

Therefore, theoretically, the rotation angle y until the transmitted light intensity becomes zero is the deviation angle y of the absorption axis of the sample 2 to be measured, but in reality, since there is noise, the transmitted light intensity is the lowest. The rotation angle up to the rotation position can be determined as the deviation angle y of the absorption axis. By displaying the relationship between the intensity of the transmitted light and the rotation angle using the recorder 6, the absorption axis deviation angle of the sample to be measured 2 can be visually confirmed immediately. In addition, when measuring the deviation angle 2 of the absorption axes of many samples to be measured from the same rod, rotate one sample to be measured and clarify the relationship between the transmitted light intensity and the deviation angle y of the absorption axis in advance. By setting the position to , it is possible to know the value of the corresponding deviation angle of the absorption axis by simply measuring the transmitted light intensity at that position without rotating other samples to be measured.

<Effects> With the above configuration, the present invention allows the deviation angle of the absorption axis of the sample to be measured to be easily and reliably known.

Since measurements can be performed quickly, it can be applied to quality control of polarizing plates and production control.

[Brief explanation of the drawing]

The figure is a perspective view of a device implementing the method of the invention. 1. Light source, 2. Sample to be measured, 3a, 3b. Polarizer, 4. Light receiver, 6. Recorder, X. Axis of orthogonal Nicol optical system. Patent applicant: Nitto Electric Industry Co., Ltd. Agent: Patent Attorney Nishi 1) Shin

Claims (1)

[Claims] Using a crossed Nicol optical system in which a light source, two polarizers, and a light receiver are arranged in a uniaxial direction, a sample to be measured placed between the two polarizers is rotated around the axis of the crossed Nicol optical system. An absorption axis deviation measuring method characterized by measuring the deviation angle of the absorption axis of the sample to be measured by measuring the intensity of the transmitted light and measuring the rotation angle to the rotational position where the intensity of the transmitted light is the lowest.