A method for detecting center deviation of an infrared optical lens

Abstract

The application discloses a center deviation detection method of an infrared optical lens, and the device comprises a rotary encoder and a servo motor for driving the rotary encoder to work, wherein the rotary encoder comprises a first rotary encoder and a second rotary encoder; the device comprises a base, an inner frame and an outer frame, the inner frame is provided with a support, a laser and a beam splitter prism are arranged in the support, and a two-dimensional PSD is further arranged on the support. The device has the advantages of simple structure, intuitive test method, symmetry performance for judging the center deviation value, simple structure, convenient debugging and maintenance, and reduced detection cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lens detection, in particular to a center deviation detection method of infrared optical lens. BACKGROUND

[0002] Lens decentration (i.e. center deviation) is the distance between the geometric axis of the lens and the optical axis. The national standard GB1224-76 describes lens decentration as the deviation of the outer circle center axis of the lens and the optical axis. For an optical system (here referring to two or more lenses), when the spherical centers of the refractive surfaces are not on the same straight line, the imaging quality will be affected.

[0003] For example, patent No. CN201611040512.6 discloses a decentration measuring device and method for aspheric mirrors and an optical centering instrument. The decentration measuring device comprises a collimator, a lens device, an air floating turntable, and a measured aspheric mirror arranged on the air floating turntable. The collimator, the lens device, and the measured aspheric mirror are arranged in sequence along the optical axis direction of the collimator, and the lens device is coaxially arranged with the collimator and converges the parallel light output by the collimator into at least two focal points. One of the focal points coincides with the vertex sphere center of the aspheric mirror, and the other focal point coincides with the best fitting sphere center of at least one ring of the aspheric mirror. This measuring method requires a centering instrument, a turntable, a collimator, and an objective lens. The detection structure is complex, inconvenient to debug and maintain, and expensive, so the detection cost is high. SUMMARY

[0004] The purpose of the present application is to provide a center deviation detection method for infrared optical lens.

[0005] The technical scheme adopted by the present application to achieve the above purpose is as follows: a center deviation detection device for infrared optical lens, comprising a rotary encoder and a servo motor for driving the encoder to work, the rotary encoder comprising a first rotary encoder and a second rotary encoder; the device comprises a base, an inner frame and an outer frame, and a support is further arranged on the base, and two opposite outer walls of the outer frame are connected with an outer connecting shaft, the outer connecting shaft is rotatably installed on the support, and the working shaft of the first rotary encoder is in transmission connection with the outer connecting shaft;

[0006] Two opposite outer walls of the inner frame are connected with an inner connecting shaft, the inner connecting shaft is rotatably installed on the outer frame, and the working shaft of the second rotary encoder is in transmission connection with the inner connecting shaft;

[0007] A support is arranged on the inner frame, a through hole is arranged in the support and penetrates the upper end face and the lower end face, a laser and a beam splitter prism are installed in the through hole in sequence from top to bottom, and a two-dimensional PSD is further installed on the support.

[0008] Further, the first rotary encoder is mounted on the support, and the second rotary encoder is mounted on the outer frame.

[0009] Further, a blind hole is arranged on the side wall of the support and penetrates the through hole, and the two-dimensional PSD is mounted in the blind hole.

[0010] Further, the device further comprises a clamping seat for mounting the infrared optical lens to be tested, and the clamping seat is arranged on the base.

[0011] A center deviation detection method of an infrared optical lens comprises the following steps:

[0012] S1, before use, the laser light is coaxial with the axial center of the infrared lens, at this time, the values of the two rotary encoders are set to zero;

[0013] S2, testing: rotate in one dimension direction to make the angle symmetrical, for example, ±1°, if the laser light and the return light of the part to be tested are not coincident, the two-dimensional PSD is used to measure the position displacement of the light spot when the symmetrical angle is measured, when in use, a calibrated part is placed in the clamping seat, the center deviation y of the calibrated part is known, the deviation position x measured by the two-dimensional PSD is known, then the center deviation when the deviation position 1 is y=K*x; the infrared optical lens to be tested is placed in the clamping seat, the deviation position x measured by the two-dimensional PSD is a certain value, then according to the coefficient K, the product of the coefficient K and the value measured by the two-dimensional PSD is the center deviation of the infrared optical lens to be tested.

[0014] The device has simple structure, does not need to use high-precision air turntable, autocollimator and additional objective lens like the traditional centering instrument, the testing method is intuitive, the center deviation value is judged according to the symmetrical performance, the device has simple structure, is convenient to debug and maintain, and the detection cost is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is a structural schematic view of the present application;

[0016] Figure 2 is a front view of Figure 1 ;

[0017] Figure 3 is a side view of Figure 1 ;

[0018] Figure 4 is a longitudinal sectional view of Figure 3 ;

[0019] Marked in the figure: 1, base, 2, support, 3, outer frame, 4, inner frame, 5, first rotary encoder, 6, second rotary encoder, 7, outer connecting shaft, 8, inner connecting shaft, 9, support, 10, laser, 11, light splitting prism, 12, two-dimensional PSD, 13, card holder, 14, infrared optical lens. DETAILED DESCRIPTION

[0020] The application will be further described in detail below in combination with the drawings and specific embodiments.

[0021] Please refer to Figures 1 to 3 In the embodiment, a center deviation detection device for an infrared optical lens is provided. The device comprises a rotary encoder and a servo motor for driving the encoder to work.

[0022] The rotary encoder comprises a first rotary encoder 5 and a second rotary encoder 6. The device further comprises a base 1, an inner frame 4 and an outer frame 3. The base 1 is further provided with a support 2. The outer frame 3 is provided with two oppositely arranged outer walls, and the outer walls are fixedly connected with an outer connecting shaft 7. The outer connecting shaft 7 is rotatably installed on the support 2, and the working shaft of the first rotary encoder 5 is in transmission connection with the outer connecting shaft 7. The first rotary encoder 5 is installed on the support 2, and the second rotary encoder 6 is installed on the outer frame 3. The device further comprises a card holder 13 for installing the infrared optical lens 14 to be detected. The card holder 13 is arranged on the base 1.

[0023] The inner frame 4 is provided with two oppositely arranged outer walls, and the outer walls are fixedly connected with an inner connecting shaft 8. The inner connecting shaft 8 is rotatably installed on the outer frame 3, and the working shaft of the second rotary encoder 6 is in transmission connection with the inner connecting shaft 8. The inner frame 4 is provided with a support 9. As shown in the figure, the support 9 is provided with a through hole penetrating through the upper end face and the lower end face. The laser 10 and the light splitting prism 11 are installed in the through hole from top to bottom. The two-dimensional PSD 12 is installed on the support 9. Figure 4

[0024] A center deviation detection method for an infrared optical lens, comprising the following steps:

[0025] S1, pre-adjustment before use, the laser light is coincided with the axial center of the infrared lens. At this time, the values of the two rotary encoders are set to zero.

[0026] ​S2, test: rotate a dimension direction, make angle symmetry such as ±1°, if laser emits light and the return light of the part to be measured do not coincide, two-dimensional PSD is used to measure the position displacement of the light spot when symmetry angle, when using, a calibrated calibration part is put into the card seat, the center offset of the known calibration part is y, the offset light spot position x measured by two-dimensional PSD, then the center offset of the offset position 1 can be obtained, y=K*x; the infrared optical lens to be measured is put into the card seat, the offset light spot position measured by two-dimensional PSD is a certain value, then the center offset of the infrared optical lens to be measured is obtained according to the coefficient K, the product of the coefficient K and the value measured by two-dimensional PSD.

[0027] Before using, the laser light and the axial center of the infrared lens coincide. At this time, the values of the two rotary encoders are set to zero. Test: rotate a dimension direction, make angle symmetry such as ±1°, at this time, the values of two-dimensional PSD are read out, and whether the symmetry is based on zero point is observed, such as Figure 4 , the left side is the laser light, and the right side is the return light of the part to be measured, the two do not coincide, two-dimensional PSD is used to measure the position displacement of the light spot when symmetry angle, when using, a calibrated calibration part (infrared optical lens) is put into the card seat, the curvature radius and the center offset of the known calibration part are known, for example, the center offset of the calibration part is 30", the offset light spot position measured by two-dimensional PSD is 0.2, then the center offset of the offset position 1 can be obtained, that is, the coefficient K is 150; the infrared optical lens to be measured is put into the card seat, the offset light spot position measured by two-dimensional PSD is a certain value, then the center offset of the infrared optical lens to be measured is obtained according to the coefficient K, the product of the coefficient K and the value measured by two-dimensional PSD. The center offset value can be directly converted by the coefficient K in the application, the shafting accuracy of the rotary encoder will not affect the accuracy of the system, and the measurement accuracy is ensured.

[0028] When the inner frame 4 and the outer frame 3 are in a horizontal state, the vertical center line of the laser light and the vertical center line of the infrared optical lens coincide.

[0029] In the application, the card seat can be detachably connected with the base, so that the card seat can be replaced according to the different sizes of the infrared optical lenses to be measured, and the universality of the device is improved. The device uses the card seat to install the infrared optical lens to be measured, and does not need to use the traditional clamp to set the infrared optical lens to be measured, so that the scratch damage of the lens is reduced.

[0030] The structures, devices and operation methods not specifically described and explained in the application are implemented according to the conventional means in the field without special description and limitation.

Claims

1. A method for detecting the centering of an infrared optical lens, the detection device comprising a rotary encoder and a servo motor for driving the encoder in operation, characterized in that: The rotary encoder comprises a first rotary encoder and a second rotary encoder; the device comprises a base, an inner frame and an outer frame, the base is further provided with a support, the outer frame is provided with two opposite outer walls, the outer walls are connected with outer connecting shafts, the outer connecting shafts are rotatably installed on the support, and the working shaft of the first rotary encoder is in transmission connection with the outer connecting shafts; the inner frame is provided with two opposite outer walls, the outer walls are connected with inner connecting shafts, the inner connecting shafts are rotatably installed on the outer frame, and the working shaft of the second rotary encoder is in transmission connection with the inner connecting shafts; the inner frame is provided with a support, the support is provided with a through hole penetrating through the upper end face and the lower end face, a laser and a light splitting prism are installed in the through hole from top to bottom, and a two-dimensional PSD is further installed on the support; The detection method comprises the following steps: S1, before use, the laser light is coaxial with the axial center of the infrared lens, at this time, the values of the two rotary encoders are set to zero; S2, test: rotate in one dimension direction, and make the angle symmetrical ±1°; if the laser light and the return light of the part to be detected are not coincident, the two-dimensional PSD is used to measure the position displacement of the light spot when the symmetrical angle is measured; when in use, a calibrated part is placed in the clamping seat, the center of the calibrated part is offset by y, the two-dimensional PSD measures the offset light spot position x, and then the offset position 1° and the center offset y=K*x can be obtained; the infrared optical lens to be detected is placed in the clamping seat, the two-dimensional PSD measures the offset light spot position as a certain value, and the product of the coefficient K and the value measured by the two-dimensional PSD is the center offset of the infrared optical lens to be detected.

2. The method of centering detection of an infrared optical lens according to claim 1, wherein: The first rotary encoder is installed on the support, and the second rotary encoder is installed on the outer frame.

3. The method of centering an infrared optical lens according to claim 1, wherein: The side wall of the support is provided with a blind hole penetrating through the through hole, and the two-dimensional PSD is installed in the blind hole.

4. The method of centering detection of an infrared optical lens according to claim 1, wherein: The device further comprises a clamping seat for installing the infrared optical lens to be detected, and the clamping seat is arranged on the base.

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