CN106842473B

CN106842473B - Multi-polarizer assembling and calibrating device and method

Info

Publication number: CN106842473B
Application number: CN201710037360.2A
Authority: CN
Inventors: 王培纲; 梁科锋; 殷德奎; 王海英
Original assignee: Shanghai Institute of Technical Physics of CAS
Current assignee: Shanghai Institute of Technical Physics of CAS
Priority date: 2017-01-19
Filing date: 2017-01-19
Publication date: 2022-11-11
Anticipated expiration: 2037-01-19
Also published as: CN106842473A

Abstract

The invention discloses a multi-polarizer assembling and calibrating device and method. The device comprises a polaroid to be assembled, a precision turntable, a modulator, a detector, a focusing lens, an upper lens cone, a reference polaroid, a reflecting prism, a collimating light source, a lower lens cone, a bottom plate, a micrometer collimator and a millivoltmeter, and particularly relates to a device for realizing high-precision assembly of a plurality of polaroids by a photoelectric detection method. The device has the advantages that: the mounting precision of the transmission shaft of the polaroid can be quantitatively measured, and the precision can reach the angle classification. The device can not only accurately determine the position of one polaroid, but also accurately position a plurality of polaroids on the same assembly at any required angle.

Description

Multi-polarizer assembling and calibrating device and method

Technical Field

The invention relates to an assembly and correction technology of a polarization detection instrument, in particular to a device for realizing high-precision assembly of a plurality of polaroids by a photoelectric detection method.

Background

Polarization is a characteristic of light, and polarization detection and imaging technologies can be applied to aspects such as atmospheric detection, ocean monitoring, resource investigation, target identification in complex backgrounds and the like. Polarizers are the primary optics of polarization-detecting instruments for the detection and analysis of polarized radiation. At present, under the condition that the position of a light transmission axis of a polaroid is known, how to improve the installation precision of the polaroid is a problem which needs to be solved.

In most of the commercially available polarizers, a thin line is cut on the periphery thereof to indicate the direction of the transmission axis, and in order to make the transmission axis coincide with the designed position, a scribing alignment method is generally used. Since the scribe lines have a certain width, and the alignment of the scribe lines is related to the subjective judgment of the observer, a large error is often caused, generally exceeding one degree. It directly affects the precision and accuracy of the polarization measurement instrument, especially when multiple polarizers are located on the same assembly.

Disclosure of Invention

The invention relates to a high-precision assembling and calibrating device and method for a polaroid, which mainly solve the problem of high-precision installation and positioning of a plurality of polaroids.

The device mainly comprises a polaroid 2 to be installed, a precision rotary table 3, a modulator 4, a detector 6, a focusing lens 8, an upper lens barrel 7, a reference polaroid 9, a reflecting prism 10, a collimation light source 11, a support 1-1, a support 2-2, a support 3-3, a lower lens barrel 13, a bottom plate 14, a micrometer collimator 15 and a millivoltmeter 16. As shown in fig. 2 (c), light emitted from the point light source passes through the collimating lens 11 and then outputs a parallel light beam, and the light beam sequentially passes through the reference polarizer 9, the modulator 4, the polarizer 2 to be mounted, and the converging lens 8 and reaches the photodetector 6. The output signal of the detector 6 is connected to a millivoltmeter 16 through a circuit 5, and a real-time signal when the light transmission axes P1 and P2 form a certain angle is given. Wherein the included angle between the P1 and the P2 is accurately controlled by the rotary table 3.

The lower lens barrel 13 is fixed on the bottom plate 14 by a screw, and the collimated light source 11 is fixed in the lower lens barrel 13 by a threaded pressing ring;

the precise rotary table 3 is fixed on the upper end surface of the lower lens barrel 13, the reference polaroid 9 is fixed at the central position on the precise rotary table 3 by a screw, and the reflecting prism 10 is fixed on the precise rotary table 3 by silica gel;

a focusing lens 8, a detector 6 and a measuring circuit board 5 connected with the detector are arranged in the upper lens barrel 7; the upper lens cone 7 is fixed on the bottom plate 14 through a bracket and a screw;

the modulator 4 is fixedly arranged between the precision turntable 3 and the upper lens barrel 7;

the filter wheel 2 is fixedly arranged between the upper lens cone 7 and the modulator 4;

the centers of the lower lens cone 13, the precision rotary table 3, the polaroid mounting hole to be mounted in the filter wheel 2 and the upper lens cone 7 are positioned on the same optical axis;

the micrometric collimator 15 is aligned with the reflecting prism 10, so that light of the micrometric collimator can return through the reflecting prism to determine the corner reference zero position of the precise rotary table 3 and the angle of the polaroid to be installed;

collimated light signals generated by the collimated light source 11 are subjected to polarization analysis through a reference polarizing film 9, the modulator 4 and a polarizing film to be installed in the filter wheel 2, and finally are irradiated onto the detector 6 through the focusing lens 8, and a measurement result is displayed by the measurement circuit board 5 and the millivoltmeter 16.

The precision rotary table 3 is an MRS300 type rotary table, the control precision is 3 ', and the angle measurement precision of the micrometric collimator 15 is 1'.

The steps of the multi-polarizer assembling and correcting method are as follows:

1) Positioning the position of the filter wheel 2 by using a positioning pin;

2) Placing a polaroid in the installation aperture, wherein the transmission axis of the polaroid is consistent with the mechanical installation reference position and is fixed by a small amount of silica gel, and the position is defined as the reference zero position of the transmission axis;

3) Rotating the precision turntable 3 to make the polaroid to be installed orthogonal to the reference polaroid and recording millivolt representation;

4) Rotating the precision rotary table 3 to enable the reference polaroid to rotate left and right at the same angle not exceeding 20 degrees and respectively record millivolt representation numbers;

5) If the two readings are not equal, taking the average value of the two readings as a target value, rotating the polaroid to be installed to change the millivolt representation number into the target value, repeating the steps until the readings of the two millivolt representations are consistent when the precision rotary table 3 rotates leftwards and rightwards for the same angle not exceeding 20 degrees, and determining that the polaroid to be installed is installed in place;

6) Rotating the filter wheel, and repeating the steps 1) to 5) to precisely assemble and calibrate the next polaroid.

The basic principle of the optical measurement of the device is as follows: according to a formula I alpha = I0cos2 alpha, alpha is an included angle between a polarization axis of the reference polarizer and a polarization axis of the polarizer to be measured, I0 is incident light intensity, and I alpha is emergent light intensity. When α =90 °, as in fig. 2 (a), the output light intensity is close to zero, and the position of α =90 ° is difficult to determine accurately due to the presence of noise in the circuit. As shown in FIG. 2 (b), when the principal axes of P1 and P2 are at the same angle between clockwise θ 1 and counterclockwise θ 2, the output light intensity is equal. By utilizing the symmetrical characteristic, certain mathematical processing is carried out, namely the accurate position of alpha =90 degrees can be accurately determined, and an accurate value is given by a set of matched high-precision angle measuring device.

The invention has the following advantages:

by using the device, the installation precision of the light transmission shaft of the polaroid can be quantitatively expressed, and the precision can reach angle classification. The device can not only accurately determine the position of one polaroid, but also accurately position a plurality of polaroids on the same assembly at any required angle.

Drawings

Fig. 1 is a device configuration diagram, fig. 1 (1) is a front view of the device, and fig. 1 (2) is a sectional view of the device, in which:

the device comprises (1) -a positioning pin, (2) -a filter wheel, (3) -a precision rotary table, (4) -a modulator, (5) -a measuring circuit board, (6) -a detector, (7) -an upper lens cone, (8) -a focusing lens, (9) -a reference polaroid, (10) -a reflecting prism, (11) -a point light source, (12-1) -a support 1, (12-2) -a support 2, (12-3) -a support 3, (13) -a lower lens cone, (14) -a bottom plate, (15) -a micrometer parallel light pipe and (16) -a millivoltmeter.

Fig. 2 is a schematic view of measurement, fig. 2 (a) is a schematic view of polarization orthogonality, fig. 2 (b) is a schematic view of arbitrary angle measurement, and fig. 2 (c) is a schematic view of light path.

Detailed Description

According to the device for mounting the polaroid with high precision, the precision rotary table is of an MRS300 type, and the reflected image and the original image are superposed through the matching of the collimator and the reflecting prism, so that the position of the precision rotary table at the moment is determined to be a reference zero position.

The mounting steps of the polaroid are as follows: (1) positioning the position of the light filtering wheel by using a positioning pin; (2) Placing a polaroid in the installation aperture, wherein the transmission axis of the polaroid is consistent with the mechanical installation reference position and is fixed by a small amount of silica gel, and the position is defined as the reference zero position of the transmission axis; (3) Rotating the precision turntable to make the polaroid to be installed orthogonal to the reference polaroid and recording millivolt representation; (4) Rotating the precision turntable to make the reference polaroid rotate at the same angle not exceeding 20 degrees (for example, 15 degrees) left and right, and recording millivolt representation numbers respectively; (5) If the two readings are not equal, taking the average value of the two readings as a target value, rotating the polaroid to be installed to change the millivolt representation number to the target value, repeating the steps until the readings of the two millivolt representations are consistent when the precision rotary table rotates leftwards and rightwards for the same angle (for example, 15 degrees) which is not more than 20 degrees, and determining that the polaroid to be installed is installed in place at the moment; (6) And rotating the filter wheel, and repeating the steps to precisely assemble and correct the next polaroid. With this arrangement, the mounting accuracy of the polarizer is better than 4.5 arcseconds.

Claims

1. A multi-polarizer assembling and calibrating device comprises a filter wheel (2), a precision rotary table (3), a modulator (4), a measuring circuit board (5), a detector (6), an upper lens barrel (7), a focusing lens (8), a reference polarizer (9), a reflecting prism (10), a collimating light source (11), a lower lens barrel (13), a bottom plate (14), a micrometer collimator (15) and a millivoltmeter (16); the method is characterized in that:

the lower lens barrel (13) is fixed on the bottom plate (14) by screws, and the collimation light source (11) is fixed in the lower lens barrel (13) by a threaded pressing ring;

the precise rotary table (3) is fixed on the upper end surface of the lower lens cone (13), the reference polaroid (9) is fixed at the central position of the precise rotary table (3) by a screw, and the reflecting prism (10) is fixed on the precise rotary table (3) by silica gel;

a focusing lens (8), a detector (6) and a measuring circuit board (5) connected with the detector are arranged in the upper lens barrel (7); the upper lens cone (7) is fixed on the bottom plate (14) through a bracket and a screw;

the modulator (4) is fixedly arranged between the precision turntable (3) and the upper lens barrel (7);

the filter wheel (2) is fixedly arranged between the upper lens cone (7) and the modulator (4);

the centers of the lower lens barrel (13), the precision rotary table (3), the polaroid mounting hole to be mounted in the filter wheel (2) and the upper lens barrel (7) are positioned on the same optical axis;

the micrometer parallel light pipe (15) is aligned to the reflecting prism (10) to enable light of the micrometer parallel light pipe to return through the reflecting prism so as to determine a corner reference zero position of the precise rotary table (3) and an angle of the polaroid to be installed;

collimated light signals generated by the collimated light source (11) are analyzed and deflected by a reference polarizing film (9), a modulator (4) and a polarizing film to be installed in the filter wheel (2), and finally are irradiated onto a detector (6) through a focusing lens (8), and a measurement circuit board (5) and a millivoltmeter (16) display measurement results.

2. The multi-polarizer alignment apparatus of claim 1, wherein: the precision rotary table (3) is an MRS300 type rotary table, the control precision is 3 ', and the angle measurement precision of the micrometric collimator (15) is 1'.

3. A method for assembling and correcting a multi-polarizer based on the multi-polarizer assembling and correcting apparatus of claim 1, comprising the steps of:

1) Positioning the position of the filter wheel (2) by using a positioning pin;

3) Rotating the precision rotary table (3) to ensure that the polaroid to be installed is orthogonal to the reference polaroid, and recording millivolt representation;

4) Rotating the precision rotary table (3) to enable the reference polaroid to rotate left and right at the same angle not exceeding 20 degrees and respectively record millivolt representation numbers;

5) If the two readings are not equal, taking the average value of the two readings as a target value, rotating the polaroid to be installed to change the millivolt representation number into the target value, repeating the steps until the precise rotary table (3) rotates left and right for the same angle which is not more than 20 degrees, the readings of the two millivolt representations are consistent, and determining that the polaroid to be installed is installed in place at the moment;

6) Rotating the filter wheel, and repeating the steps 1) to 5) to precisely assemble and correct the next polaroid.