JP2712987B2 - Adjustment method of polarization measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a goniometer, a polarizer,
In a polarimeter equipped with an analyzer,
And a method for adjusting the polarization reference plane of the element. Here the polarizing group
The term “quasi-plane” refers to the plane assumed to be fixed to the polarizing element.
Parallel to the direction in which the light of the optical element is transmitted, for example, with a polarizer
If present, parallel to the plane of polarization of linearly polarized light transmitted through the polarizer
Or, if it is a vertical plane or a quarter-wave plate, the incident linearly polarized light is
Two directions appearing as linearly polarized light are orthogonal to each other
So one of them.

[0002]

2. Description of the Related Art A polarimeter measures the polarization characteristics of a sample.
In the instrument, the measurement operation is basically between the polarizer and the analyzer.
Place the sample on the surface and measure the light passing through the polarizer, sample, and analyzer
At this time, the polarizer and the analyzer change the light transmission direction.
Rotatable as an axis, at one angular position of the polarizer
On the other hand, the angle position where the analyzer transmitted light intensity becomes maximum or minimum
And repeat these operations while changing the angular position of the polarizer.
I will return. Therefore, in polarimetry, polarizers, analyzers, etc.
Since the measurement of the angular position is the center of the measurement operation, the polarization element
It is necessary to determine the standard for measuring the angular position.
is there. This reference is on the side of the polarimeter and on the side of each polarizer.
The reference on the polarizing element side is the above-mentioned polarization reference plane.
This polarization reference plane is aligned with one direction that is the reference on the device side.
Determine the angle position of each polarizing element when it is parallel or perpendicular to 0.
I can. What is the position of each polarizing element from this angular position 0?
The rotation is read as measurement data. in this way
The read angular position is called the azimuth of the polarizing element . In the polarization measuring device, it is necessary to adjust the polarization reference plane of a polarizing element such as a polarizer, a quarter-wave plate, and an analyzer so as to be parallel or perpendicular to the rotation axis of the goniometer of the polarization measuring device. Each polarizing element is rotatable about the optical axis of the measurement optical path, and a contact is provided between the polarizing element holder and the polarizing element so that the polarization reference plane of each polarizing element is automatically determined mechanically. Even so, wear occurs in the mechanism during use, so that it is sometimes necessary to adjust the polarization reference plane. However, conventional polarization measuring devices are not provided with a device for easily adjusting the polarization reference plane at any time, and when adjustment of the polarization reference plane is required, special measures are taken using the measurement sample to perform polarization. The reference plane is verified.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method capable of easily adjusting a polarization reference plane of a polarization measuring device at any time.

[0004]

The polarization measuring device is provided with an adjusting polarizer in addition to the measuring polarizers, the quarter-wave plate, the analyzer, etc., which the polarization measuring device originally has. ,
At the time of adjustment, this adjustment polarizer is placed on a sample table so that its polarization reference plane is substantially parallel to the rotation axis of the goniometer of the polarization measuring device. The light is transmitted through the analyzer and the analyzer, the analyzer is turned so that the light detection output becomes 0 or the maximum, the direction of the analyzer at that time is stored, and then the sample table is turned by 180 °. By performing the same operation as above, the azimuth of the other polarizing element is adjusted with reference to the intermediate azimuth of the azimuths of the two analyzers before and after.

[0005]

According to the above-described operation, first, the orientation of the polarization reference plane of the analyzer becomes parallel (perpendicular) to the rotation axis of the goniometer.
In this operation, the goniometer is turned 180 ° and the measurement is performed twice with the direction of the adjustment polarizer being reversed. When turned, the reference plane of the adjusting polarizer before and after that is symmetrically inclined with respect to the rotation axis of the goniometer, so the middle of the azimuth angle of the analyzer obtained in the two measurements is the polarization reference of the analyzer. It is the correct orientation of the surface.

[0006]

FIG . 1 shows a polarization measuring device. 1 is goniome
The goniometer is an angle scale disk whose center is
Rotated by an axis perpendicular to the surface of the angle scale disk
A sample stage 2 and rotating arms 3 and 7. Goniome
The angle between arms 3 and 7 is measured by the angle
You. Light source 4 and polarizer 5 on arm 3 and 1/4 when necessary
Wave plate is attached. An analyzer 8 and light detection on the arm 7
A vessel 9 is mounted. Polarizer 5, analyzer 8, 1/4
Each of the wave plates 6 and the like has a light transmission direction, that is, the light source 4 in the drawing.
It is rotatable about a straight line connecting the light detectors 9 as an axis.
The rotation angle can be read . For sample measurement
In this case, the sample is placed at a position where the polarizer for adjustment 10 is located. Polarization measurement
In many cases, the reflected light from the sample surface is examined.
Are arms 3 and 7 so that the reflection condition is satisfied with respect to the sample surface.
, And read the angle of incidence and reflection with a goniometer.
is there. The present invention is a preparatory work before sample measurement with this device.
And the polarizer as described in the background section.
5, the polarization reference planes of the analyzer 8, the 1/4 wavelength plate 6, etc.
One direction, fixed to the line and to the polarimeter, this
In the example, it is parallel to the direction perpendicular to the goniometer panel
Adjust as follows. FIG. 1 shows the operation of the method of the present invention.
An example of the work will be described. In the figure, 1 is a goniometer, 2 is a sample stage located at the center of the goniometer, and 3 is a rotating arm of one of the goniometers, holding a light source 4, a polarizer 5 for measurement, and a 1/4 wavelength plate 6. Reference numeral 7 denotes the other rotating arm of the goniometer, which holds the analyzer 8 and the photodetector 9. The above is the structure of the ordinary polarization measuring device. When performing a polarization reference plane adjustment for aligning the polarization reference planes of the respective polarization elements 5, 6, 8 with the central axis of the goniometer (vertically), the adjustment polarizer 10 is mounted on the sample table 2. At this time, since the bottom surface of the adjusting polarizer 10 is perpendicular to the polarization reference plane of the polarizer,
When placed on the sample table 2, the polarization reference plane of the adjusting polarizer 10 is substantially parallel to the center axis (vertical direction) of the goniometer within the range of accuracy of the bottom surface. The arms 3 and 7 of the goniometer are positioned on a straight line, the light source 4 is turned on, and the analyzer 8 is turned so that the output of the photodetector 9 is 0, and is actually a minimum. The azimuth angle of the analyzer 8 at this time is read and stored. This direction is the direction in which the polarization reference plane of the analyzer 8 is substantially horizontal. Next, the sample table 2 is turned by 180 °, and the analyzer 8 is turned again so that the output of the photodetector 9 becomes 0, and the azimuth angle of the analyzer 8 at that time is read. An intermediate point between the previously stored azimuth angle and the azimuth angle read later is the azimuth angle at which the polarization reference plane of the analyzer 8 is exactly horizontal. Since the polarization reference plane of the analyzer 8 has been accurately adjusted in the horizontal direction in this way, the quarter wave plate 6 is removed except for the adjustment polarizer 10 so that the output of the photodetector 9 becomes zero. When the polarizer 5 is turned, the polarization reference plane of the polarizer 5 is accurately perpendicular.
This is because the polarization reference plane of the analyzer 8 is accurately adjusted horizontally. After the adjustment of the polarizer 5 and the analyzer 8 is completed in this way, the 波長 wavelength plate 6 is set. In the Senarmont method, the quarter-wave plate is placed at an azimuth of 45 °. Therefore, when the following operation is performed with a polarizer of 45 ° and an analyzer of 135 °, the 波長 wavelength plate has a 45 ° azimuth. 1 /
When a four-wavelength plate is placed, the linearly polarized light exiting the polarizer 5 becomes elliptically polarized light and enters the analyzer 8, so that the output of the photodetector 9 is not zero. Therefore, the 波長 wavelength plate 6 is turned so that the output of the photodetector 9 becomes 0 again. In this case, the polarization reference plane of the 波長 wavelength plate 6 is accurately perpendicular. Although the adjusting polarizer 10 may be stored in an arbitrary place separately from the polarization measuring device, it may be stored in an appropriate place in the polarization measuring device, for example, the sample table 2.
It is convenient to have it built in under.

[0007]

According to the present invention, the user of the apparatus does not need to disassemble the apparatus and can easily reproduce the same accurate polarization reference plane as adjusted in the assembly adjustment process at the manufacturer at any time. .

[Brief description of the drawings]

FIG. 1 is a plan view of an example of a polarization measurement device that performs the method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Goniometer 2 Sample stand 3 Rotating arm of goniometer 4 Light source 5 Polarizer 6 1/4 wavelength plate 7 Rotating arm of goniometer 8 Analyzer 9 Photodetector 10 Polarizer for adjustment

Claims (1)

(57) [Claims] 1. A polarization measuring device is provided with an adjusting polarizer in addition to each polarizing element such as a measuring polarizer, a quarter-wave plate, and an analyzer that the polarization measuring device originally has. The adjustment polarizer is placed on the sample table such that its polarization reference plane is substantially parallel to the rotation axis of the goniometer of the polarimeter, and the polarizer, quarter-wave plate, adjustment polarizer, The light is transmitted through the photon, the analyzer is turned so that the light detection output becomes 0 or the maximum, the direction of the analyzer at that time is stored, and then the sample table is turned by 180 °, and the top and the bottom are turned. A method for adjusting a polarization measuring device, characterized in that the same operation is performed to adjust the azimuth of another deflecting element with reference to the intermediate azimuth of the two directions of the analyzer before and after.