CN106842473A - A kind of many polarization calibration devices on chip and dress calibration method - Google Patents

Abstract

The invention discloses a multi-polarizer alignment device and an alignment method. The device includes a polarizer to be installed, a precision turntable, a modulator, a detector, a focusing lens, an upper lens barrel, a reference polarizer, a reflecting prism, a collimated light source, a lower lens barrel, a bottom plate, a micrometric collimator, and a millivoltmeter. Specifically, it refers to a device that realizes high-precision assembly of multiple polarizers through a photoelectric detection method. The advantage of the device is that the installation accuracy of the light transmission axis of the polarizer can be quantitatively measured, and the accuracy can reach angle classification. Using this device can not only accurately determine the position of a polarizer, but also realize accurate positioning of multiple polarizers on the same component at any required angle.

Description

A multi-polarizer alignment device and alignment 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 multiple polarizers through a photoelectric detection method.

Background technique

Polarization is a characteristic of light. Polarization detection and imaging technology can be applied to atmospheric detection, ocean monitoring, resource investigation, and target recognition in complex backgrounds. Polarizers are the basic optics of polarization detection instruments for the detection and analysis of polarized radiation. At present, how to improve the installation accuracy of the polarizer is a problem that must be solved when the position of the light transmission axis of the polarizer is known.

Most commercially available polarizers are engraved with a thin line on its periphery to indicate the direction of the light transmission axis. In order to make the light transmission axis consistent with the design position, the engraved line alignment method is generally used. Since the engraved line has a certain width, and the alignment of the engraved line is related to the subjective judgment of the observer, it often causes a large error, generally exceeding one degree. It directly affects the precision and accuracy of polarization measurement instruments, especially when multiple polarizers on the same component need to be positioned accurately.

Contents of the invention

The invention relates to a polarizer high-precision installation and calibration device and a calibration method, which mainly solve the problem of high-precision installation and positioning of multiple polarizers.

The device mainly includes a polarizer to be installed 2, a precision turntable 3, a modulator 4, a detector 6, a focusing lens 8, an upper barrel 7, a reference polarizer 9, a reflective prism 10, a collimated light source 11, a bracket 1 12-1, Support 2 12-2, support 3 12-3, lower lens barrel 13, base plate 14, micrometer collimator 15, millivolt meter 16. As shown in Fig. 2(c), the light emitted by the point light source passes through the collimating lens 11 and then outputs a parallel beam. The output signal of the detector 6 is connected to the millivoltmeter 16 through the circuit 5, and the real-time signal when the light transmission axes of P1 and P2 form a certain angle is given. The angle between P1 and P2 is precisely controlled by the turntable 3 .

The lower lens barrel 13 is fixed on the base plate 14 with screws, and the collimated light source 11 is fixed in the lower lens barrel 13 with a threaded pressure ring;

The precision turntable 3 is fixed on the upper end surface of the lower lens barrel 13, the reference polarizer 9 is fixed on the center position of the precision turntable 3 with screws, and the reflective prism 10 is fixed on the precision turntable 3 with silica gel;

A focusing lens 8, a detector 6 and a measuring circuit board 5 connected to the detector are installed in the described upper lens barrel 7; the upper lens barrel 7 is fixed on the base plate 14 by a bracket and screws;

The modulator 4 is fixedly installed between the precision turntable 3 and the upper barrel 7;

The filter wheel 2 is fixedly installed between the upper barrel 7 and the modulator 4;

The mounting hole of the polarizer to be installed in the lower lens barrel 13, the precision turntable 3, the filter wheel 2 and the center of the upper lens barrel 7 are on an optical axis;

Described micrometric collimator 15 aligns with reflective prism 10 so that the light of micrometric collimator can return through reflective prism, to determine the angle of reference zero position of the rotation angle of precision turntable 3 and the angle of polarizer to be installed;

The collimated light signal produced by the collimated light source 11 is analyzed by the polarizer to be installed in the reference polarizer 9, the modulator 4 and the filter wheel 2, and finally irradiated on the detector 6 through the focusing lens 8, and the measuring circuit 5 and mV Table 16 shows the measurement results.

The precision turntable 3 is an MRS300 type turntable with a control accuracy of 3″, and the angle measurement accuracy of the micrometric collimator 15 is 1″.

The steps of multi-polarizer installation method are as follows:

1) Position the filter wheel 2 with the positioning pin;

2) Place the polarizer in the installation aperture. The light transmission axis of the polarizer is consistent with the mechanical installation reference position, and fixed with a small amount of silica gel. This position is defined as the reference zero position of the light transmission axis;

3) Rotate the precision turntable 3 so that the polarizer to be installed is orthogonal to the reference polarizer, and record the millivolt indication;

4) Rotate the precision turntable 3 so that the left and right sides of the reference polarizer are rotated at the same angle of not more than 20°, and record the millivolt indications respectively;

5) If the two indications are not equal, take the average value of the two indications as the target value, rotate the polarizer to be installed, so that the indicated value of millivolts becomes the target value, and repeat this process until the precision turntable 3 is rotated left and right by the same different value. When the angle exceeds 20°, the readings of the two millivolt meters are consistent, and it is considered that the polarizer to be installed is in place at this time;

6) Rotate the filter wheel, repeat the above steps 1) to 5), and carry out the precise adjustment of the next polarizer.

The basic principle of optical measurement of the device is: according to the formula Iα=I0cos2α, α is the angle between the polarization axis of the reference polarizer and the polarization axis of the polarizer to be measured, I0 is the incident light intensity, and Iα is the outgoing light intensity. When α=90°, as shown in Figure 2(a), the output light intensity is close to zero. Due to the noise in the circuit, it is difficult to accurately determine the position of α=90°. As shown in Figure 2(b), when the angle between the clockwise θ1 and the counterclockwise θ2 of the main axes of P1 and P2 is the same, the output light intensity is equal. Utilizing this symmetry feature and performing certain mathematical processing, the exact position of α=90° can be accurately determined, and an accurate value can be given by a matching high-precision angle measuring device.

The present invention has the following advantages:

With this device, the installation accuracy of the light transmission axis of the polarizer can be expressed quantitatively, and the accuracy can reach angle classification. Using this device can not only accurately determine the position of a polarizer, but also realize accurate positioning of multiple polarizers on the same component at any required angle.

Description of drawings

Fig. 1 is a device mechanism diagram, Fig. 1 (1) is a front view of the device, and Fig. 1 (2) is a sectional view of the device, among the figures:

(1)-locating pin, (2)-filter wheel, (3)-precision turntable, (4)-modulator, (5)-measurement circuit board, (6)-detector, (7)-upper tube , (8)-focusing lens, (9)-reference polarizer, (10)-reflecting prism, (11)-point light source, (12-1)-support 1, (12-2)-support 2, (12 -3)-support 3, (13)-lower lens barrel, (14)-base plate, (15)-micrometric collimator, (16)-millivoltmeter.

Figure 2 is a schematic diagram of measurement, Figure 2(a) is a schematic diagram of polarization orthogonality, Figure 2(b) is a schematic diagram of arbitrary angle measurement, and Figure 2(c) is a schematic diagram of an optical path.

detailed description

According to a device for installing polarizers with high precision described in the manual, the precision turntable uses the MRS300 type. Through the cooperation of the collimator and the reflective prism, the reflected image and the original image are overlapped, that is, the position of the precision turntable at this time is determined as the reference zero.

The polarizer installation steps are as follows: (1) Position the filter wheel with positioning pins; (2) Place the polarizer in the installation aperture, the light transmission axis of the polarizer is consistent with the mechanical installation reference position, and fix it with a small amount of silica gel. Defined as the reference zero position of the light transmission axis; (3) Rotate the precision turntable so that the polarizer to be installed is perpendicular to the reference polarizer, and record the number of millivolts; (4) Rotate the precision turntable so that the left and right rotations of the reference polarizer are the same (5) If the two indications are not equal, take the average value of the two indications as the target value, and rotate the polarizer to be installed so that the millivolts The volt display value becomes the target value, and so on, until the precision turntable rotates left and right at the same angle not exceeding 20° (for example, 15°), and the readings of the two millivolt meters are consistent, then it is considered that the polarization to be installed at this time (6) Rotate the filter wheel and repeat the above steps to carry out the precise adjustment of the next polarizer. With this device, the installation accuracy of the polarizer is better than 4.5 arc seconds.

Claims (3)

1. A multi-polarizer assembly and calibration device, comprising a filter wheel (2), a precision turntable (3), a modulator (4), a measurement circuit board (5), a detector (6), an upper lens barrel (7), a focusing Lens (8), reference polarizer (9), reflective prism (10), collimated light source (11), lower lens barrel (13), bottom plate (14), micrometric collimator (15), millivolt meter ( 16); characterized in that: The lower lens barrel (13) is fixed on the base plate (14) with screws, and the collimated light source (11) is fixed in the lower lens barrel (13) with a threaded pressure ring; The precision turntable (3) is fixed on the upper end face of the lower lens barrel (13), the reference polarizer (9) is fixed on the center position on the precision turntable (3) with screws, and the reflective prism (10) is fixed on the precision turntable ( 3) on; A focusing lens (8) and a detector (6) and a measurement circuit board (5) connected to the detector are installed in the described upper lens barrel (7); the upper lens barrel (7) is fixed on the base plate (14) by a bracket and screws ; The modulator (4) is fixedly installed between the precision turntable (3) and the upper lens barrel (7); The filter wheel (2) is fixedly installed between the upper lens barrel (7) and the modulator (4); The center of the polarizer installation hole to be installed in the lower lens barrel (13), the precision turntable (3), the filter wheel (2) and the upper lens barrel (7) is on an optical axis; Described micrometric collimator (15) is aligned with reflective prism (10) so that the light of micrometric collimator can return through reflective prism, to determine the rotation angle reference zero position of precision turntable (3) and the polarizer to be installed. angle; The collimated light signal produced by the collimated light source (11) is analyzed by the polarizer to be installed in the reference polarizer (9), the modulator (4) and the filter wheel (2), and finally through the focusing lens (8 ) is irradiated on the detector (6), and the measurement circuit (5) and the millivolt meter (16) display the measurement result. 2. A kind of multi-polarizer installation and calibration device according to claim 1, characterized in that: the precision turntable (3) is an MRS300 type turntable with a control accuracy of 3″, and the micrometer collimator (15) measures Angular accuracy is 1". 3. A multi-polarizer alignment method based on the multi-polarizer alignment device according to claim 1, characterized in that it comprises the following steps: 1) Locate the position of the filter wheel (2) with the positioning pin; 2) Place the polarizer in the installation aperture. The light transmission axis of the polarizer is consistent with the mechanical installation reference position, and fixed with a small amount of silica gel. This position is defined as the reference zero position of the light transmission axis; 3) Rotate the precision turntable (3) so that the polarizer to be installed is perpendicular to the reference polarizer, and record the millivolt representation; 4) Rotate the precision turntable (3) so that the left and right sides of the reference polarizer rotate at the same angle not exceeding 20°, and record the millivolt indications respectively; 5) If the two indications are not equal, take the average value of the two indications as the target value, turn the polarizer to be installed, so that the millivolt indication becomes the target value, and repeat this until the precision turntable (3) rotates left and right at the same When the angle does not exceed 20°, if the readings of the two millivolt meters are consistent, it is considered that the polarizer to be installed is in place at this time; 6) Rotate the filter wheel, repeat the above steps 1) to 5), and carry out the precise adjustment of the next polarizer.