Auto-collimator

Abstract

The utility model discloses an autocollimator, which belongs to the technical field of collimators and is characterized in that the optical axis of a system is calibrated by using a collimated light beam and optical detection equipment, the offset and inclination of the optical axis of a to-be-detected lens are minimized, and the vertical position relation between the collimated light beam and an image sensitive surface is confirmed by calibrating the center of mass of a light spot. The calibration process ensures the accuracy of the optical axis of the system, collimated light is reflected on the upper and lower surfaces of the to-be-measured lens, the reflected light reaches the telecentric camera through the beam splitter, the micro inclination between the optical axis of a sample and the optical axis of the system is monitored by using the property of the telecentric camera for parallel light imaging, and the system can be directly used for a system with strict lens centering requirements. Transmission light and reflected light of the to-be-measured lens can be measured at the same time, measurement accuracy is improved, accurate alignment of the optical axis of the lens and the optical axis of the system is ensured, and adjustment is more accurate.

Description

Technical Field

[0001] The utility model relates to a self-collimator, belonging to the technical field of collimators. Background Art

[0002] With the rapid advancement of science and technology, optics has been widely used in various fields. Among them, lenses are key components in the field of optics, and their center thickness is considered to be one of the most important parameters. This parameter directly determines the performance of the optical system. During the production process, there may be some errors in the center thickness of the lens, which makes it particularly important to accurately measure its center thickness to ensure the high performance of the optical system.

[0003] For example, the autocollimator disclosed in the application number: 202120814616.8 includes: a base; a screw rod, which is vertically arranged on the base; a coarse adjustment mechanism, including a clamping part sleeved on the screw rod and a telescopic part connected to the clamping part; a fine adjustment mechanism, including a fixed part connected to the telescopic part and a rotating part connected to the fixed part, and a clamp is arranged on the rotating part; a lens barrel, which is inserted into the clamp; and a light source, which is connected to the lens barrel. The utility model provides the autocollimator with multi-degree-of-freedom adjustment capability by arranging a coarse adjustment mechanism and a fine adjustment mechanism in the autocollimator.

[0004] The first step in measuring the center thickness of a lens is to locate the center of the lens. Currently, the center measurement of a lens mainly adopts two methods: contact and non-contact. Although contact measurement, such as three-coordinate measurement technology, has high accuracy, it has obvious disadvantages, including possible damage to the lens, slow measurement speed and low efficiency. On the other hand, non-contact measurement methods can be divided into interferometry and autocollimation according to their measurement principles. Interferometry can provide extremely high measurement accuracy, but it is easily affected by environmental conditions and the equipment is relatively expensive. The existing autocollimation method generally requires the configuration of a precision rotating axis to rotate the lens. The performance of the rotating axis depends largely on the stability of the system, and because the rotation of the lens needs to be precisely controlled by the rotating axis, this process may be relatively slow, resulting in a longer overall measurement time. At the same time, this method may not be suitable for all types and sizes of lenses, especially for large or heavy lenses, where rotation control may be more difficult. Therefore, it is urgent to develop a high-precision and fast lens centering system to improve measurement efficiency and accuracy. Utility Model Content

[0005] The main purpose of the utility model is to provide an autocollimator.

[0006] The purpose of the utility model can be achieved by adopting the following technical solutions:

[0007] An autocollimator includes a frame for supporting and limiting;

[0008] A displacement structure for shifting is installed on the frame, a CMOS camera is installed under the displacement structure on the frame, a four-dimensional stage is installed on the CMOS camera, a lens to be tested is installed on the four-dimensional stage, and a laser light source is installed on the displacement structure;

[0009] An operating structure is installed in the displacement structure, and a limiting structure is installed in the displacement structure.

[0010] Preferably, the operating structure includes a telecentric camera, a beam splitter and an optical path plate;

[0011] An optical path plate is installed on one side of the displacement structure, a beam splitter is installed on one side of the optical path plate, and a telecentric camera is installed on the upper end of the frame.

[0012] Preferably, the limiting structure includes a fixing block, a displacement block, a pressing sheet and a screw;

[0013] A fixed block is installed on the telecentric camera, displacement blocks are installed on both sides of the fixed block, a pressing piece is installed on the displacement block, and screws are installed on the displacement block and the pressing piece.

[0014] Preferably, movable and adjustable cavities are provided on the pressing sheet and the displacement block.

[0015] Preferably, the telecentric camera, beam splitter and optical path plate in the displacement structure are used in conjunction with the lens to be tested, the four-dimensional stage and the CMOS camera.

[0016] Preferably, the fixed block can be adjustably connected along the displacement blocks on both sides.

[0017] Beneficial technical effects of the utility model:

[0018] The utility model provides a self-collimator

[0019] Advantage 1: The optical path design of this technology is relatively simple, but it can measure the transmitted light and reflected light of the lens to be tested at the same time, which improves the accuracy of the measurement.

[0020] Advantage 2: This technology uses a precision optical four-dimensional translation stage, which enables the operator to very accurately adjust the position of the lens to be tested to ensure that the optical axis of the lens is accurately aligned with the optical axis of the system.

[0021] Advantage 3: This technology uses the light spot received by the CMOS camera for center calibration and combines it with a telecentric camera to monitor the reflected light spot. This design can accurately monitor the offset and tilt between the optical axes, allowing for more precise adjustments.

[0022] Advantage 4: Through repeated adjustment and monitoring, this system can achieve self-alignment between the system and the lens to be tested, and can be calibrated even in the case of slight tilt, thus improving the efficiency and accuracy of self-alignment. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the overall three-dimensional structure of a preferred embodiment of an autocollimator according to the utility model;

[0024] Figure 2 It is a partial structural schematic diagram of a preferred embodiment of an autocollimator according to the utility model;

[0025] Figure 3 It is a side view of a preferred embodiment of an autocollimator according to the utility model.

[0026] In the figure: 1. displacement structure; 2. laser light source; 3. lens to be tested; 4. four-dimensional stage; 5. CMOS camera; 6. telecentric camera; 7. beam splitter; 8. optical path plate; 9. fixing block; 10. displacement block; 11. pressing piece; 12. screw. DETAILED DESCRIPTION

[0027] In order to make the technical solution of the present invention more clear and specific to those skilled in the art, the present invention is further described in detail below in conjunction with embodiments and drawings, but the implementation methods of the present invention are not limited thereto.

[0028] like Figure 1 - Figure 3 As shown, an autocollimator provided in this embodiment includes a frame 13 for supporting and limiting;

[0029] A displacement structure 1 for shifting is installed on the frame 13, a CMOS camera 5 is installed correspondingly under the displacement structure 1 on the frame 13, a four-dimensional stage 4 is installed on the CMOS camera 5, a lens to be tested 3 is installed on the four-dimensional stage 4, and a laser light source 2 is installed on the displacement structure 1;

[0030] An operating structure is installed in the displacement structure 1, and a limiting structure is installed in the displacement structure 1.

[0031] The operating structure includes a telecentric camera 6, a beam splitter 7 and an optical path plate 8;

[0032] An optical path plate 8 is installed on one side of the displacement structure 1 , a beam splitter 7 is installed on one side of the optical path plate 8 , and a telecentric camera 6 is installed on the upper end of the frame 13 .

[0033] The limiting structure includes a fixing block 9, a displacement block 10, a pressing sheet 11 and a screw 12;

[0034] A fixed block 9 is installed on the telecentric camera 6 , displacement blocks 10 are installed on both sides of the fixed block 9 , a pressing sheet 11 is installed on the displacement block 10 , and screws 12 are installed on the displacement block 10 and the pressing sheet 11 .

[0035] The pressing sheet 11 and the displacement block 10 are provided with movable and adjustable cavities.

[0036] The telecentric camera 6 , the beam splitter 7 and the optical path plate 8 in the displacement structure 1 are used in conjunction with the lens to be tested 3 , the four-dimensional stage 4 and the CMOS camera 5 .

[0037] The fixed block 9 can be adjusted and connected along the displacement blocks 10 on both sides.

[0038] like Figure 1 - Figure 3 As shown, the working process of an autocollimator provided in this embodiment is as follows:

[0039] Step 1: After the laser light source 2 is adjusted to a suitable height by the displacement structure 1, the collimated light beam emitted by the laser light source 2 first passes through the beam splitter 7 and is divided into two beams. One beam of light is transmitted downward. This downward beam of light passes through the central through hole of the four-dimensional stage 4 and is received by the center of the image-sensitive surface of the CMOS camera 5 to form a light spot. The light intensity of the light spot is Gaussian distributed on the image-sensitive surface. The center coordinates of the image-sensitive surface light spot can be obtained by fitting the grayscale information of the light spot by the least squares method. The center coordinates are calibrated. At this time, the collimated light beam and the image-sensitive surface are considered to be in a vertical position. Relationship, the collimated light beam is used as the optical axis of the system, and the other beam of light is received by the telecentric camera 6. The telecentric camera 6 is mounted on the fixed block 9 and connected to the displacement block 10 by screws, and then the entire structure is fixed on the optical path plate 8 by the pressing plate 11. This design allows the displacement adjustment of the telecentric camera parallel to the direction of the optical path plate and perpendicular to the direction of the optical path plate, as well as the fine adjustment of the pitch angle of the telecentric camera 6 to meet different observation needs. Through the above adjustments, the light spot is controlled to fall on the center position of the image-sensitive surface, the center coordinates are calibrated, and the preliminary adjustment is completed;

[0040] Step 2: The lens 3 to be tested is placed on the four-dimensional stage 4, and a part of the collimated light passes through the lens 3 to be tested and is transmitted to the image-sensitive surface of the CMOS camera 5. When the lens 3 to be tested is offset from the system optical axis, the center coordinate of the image formed by the transmitted light on the image-sensitive surface is displaced relative to the calibrated center coordinate. By adjusting the X-axis and Y-axis directions of the four-dimensional stage 4, the imaging center of the lens transmitted light coincides with the calibrated center coordinate position, thereby realizing the calibration of the offset between the sample optical axis and the system optical axis;

[0041] Step 3: When collimated light irradiates the lens 3 to be tested, it will be reflected on the upper and lower surfaces of the lens. These reflected lights then pass through the beam splitter 7 and are finally transmitted to the telecentric camera 6. The telecentric camera 6 is selected for its ability to image parallel light and plays a key role in this system. When there is a slight tilt between the optical axis of the sample and the optical axis of the system, the image formed by the reflected light on the lens surface in the telecentric camera 6 will show this tilt. If a clear imaging spot can be seen in the display of the telecentric camera 6, it means that the offset between the two optical axes has been reduced to a very small extent through the optical axis offset calibration. However, if the center points of the two observed imaging spots do not coincide, this clearly indicates the existence of a tilt phenomenon. Adjust the four-dimensional stage 4 so that the centers of the two spots on the telecentric camera 6 coincide, and at the same time ensure that the sample transmission spot received by the image-sensitive surface of the CMOS camera 5 is located at the position of the initial center coordinate, so that the self-collimation of the system and the lens to be tested is completed.

[0042] Example

[0043] like Figure 1 - Figure 3As shown, a laser light source 2 is installed on the displacement structure 1, a CMOS camera 5 is installed at the bottom of the displacement structure 1, a four-dimensional stage 4 is installed on the CMOS camera 5, a lens to be tested 3 is installed on the four-dimensional stage 4, a telecentric camera 6 is installed in the displacement structure 1, an optical path plate 8 is installed on the telecentric camera 6, a beam splitter 7 is installed on the optical path plate 8, the beam splitter 7 is used in conjunction with the telecentric camera 6, the telecentric camera 6 is installed on a fixed block 9, and the fixed block 9 is connected to the displacement block 10 by a screw 12 penetrating a pressing sheet 11. After the laser light source 2 is adjusted to a suitable height by the displacement structure 1, the collimated light beam emitted by the laser light source 2 is first It first passes through the beam splitter 7 and is divided into two beams. One beam of light is transmitted downward, and the downward beam of light passes through the central through hole of the four-dimensional stage 4 and is received by the center of the image-sensitive surface of the CMOS camera 5 to form a light spot. The light intensity of the light spot is Gaussian distributed on the image-sensitive surface. The center coordinates of the image-sensitive surface light spot can be obtained by fitting the grayscale information of the light spot by the least squares method. The center coordinates are calibrated. At this time, the collimated light beam and the image-sensitive surface are considered to be in a vertical position relationship. The collimated light beam serves as the optical axis of the system. At the same time, the other beam of light is received by the telecentric camera 6. The telecentric camera 6 is mounted on the fixed block 9 and connected to the displacement block 10 by screws, and then the entire structure is fixed on the optical path disk 8 by the pressing piece 11.This design allows the telecentric camera to be adjusted in displacement parallel to and perpendicular to the optical path disk, as well as the telecentric camera 6 to be finely adjusted in pitch angle to meet different observation requirements. Through the above adjustments, the light spot is controlled to fall on the center position of the image-sensitive surface, and the center coordinates are calibrated to complete the preliminary adjustment. The lens 3 to be tested is placed on the four-dimensional stage 4. A part of the collimated light passes through the lens 3 to be tested and is transmitted to the image-sensitive surface of the CMOS camera 5. When the lens 3 to be tested is offset from the optical axis of the system, the center coordinates of the image formed by the transmitted light on the image-sensitive surface are relatively There is a displacement with respect to the calibrated center coordinate. By adjusting the X-axis and Y-axis directions of the four-dimensional stage 4, the imaging center of the lens transmitted light coincides with the calibrated center coordinate position, and the calibration of the offset between the sample optical axis and the system optical axis is realized. When the collimated light irradiates the lens 3 to be tested, it will be reflected on the upper and lower surfaces of the lens. These reflected lights then pass through the beam splitter 7 and are finally transmitted to the telecentric camera 6. The telecentric camera 6 is selected for its ability to image parallel light and plays a key role in this system. When there is a slight difference between the optical axis of the sample and the optical axis of the system, When the lens is tilted, the image formed by the reflected light on the lens surface in the telecentric camera 6 will show this tilt. If a clear imaging spot can be seen in the display of the telecentric camera 6, it means that the offset between the two optical axes has been reduced to a very small degree through the optical axis offset calibration. However, if the center points of the two observed imaging spots do not coincide, this clearly indicates that there is a tilt phenomenon. The four-dimensional stage 4 is adjusted so that the centers of the two spots on the telecentric camera 6 coincide. At the same time, it is ensured that the sample transmission spot received by the image-sensitive surface of the CMOS camera 5 is located at the position of the initial center coordinate. The system optical axis is calibrated using a collimated beam and an optical detection device to ensure that the optical axis offset and tilt of the lens to be tested are minimized. By calibrating the centroid of the spot, the vertical position relationship between the collimated beam and the image-sensitive surface is confirmed. This calibration process ensures the accuracy of the system optical axis. The collimated light is reflected on the upper and lower surfaces of the lens to be tested. These reflected lights reach the telecentric camera through a beam splitter. The property of the telecentric camera to image parallel light is used to monitor the slight tilt between the sample optical axis and the system optical axis. It can be directly used in systems with strict requirements on lens centering.

[0044] The above is only a further embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes within the scope disclosed by the present invention according to the technical solution and concept of the present invention, which fall within the protection scope of the present invention.

Claims

1. An autocollimator, comprising a frame (13) for supporting and limiting; Features: A displacement structure (1) for shifting is installed on the frame (13); a CMOS camera (5) is installed correspondingly below the displacement structure (1) on the frame (13); a four-dimensional stage (4) is installed on the CMOS camera (5); a lens to be tested (3) is installed on the four-dimensional stage (4); and a laser light source (2) is installed on the displacement structure (1); An operating structure is installed in the displacement structure (1), and a limiting structure is installed in the displacement structure (1).

2. An autocollimator according to claim 1, characterized in that: The operating structure includes a telecentric camera (6), a beam splitter (7) and an optical path plate (8); An optical path plate (8) is installed on one side of the displacement structure (1), a beam splitter (7) is installed on one side of the optical path plate (8), and a telecentric camera (6) is installed on the upper end of the frame (13).

3. An autocollimator according to claim 2, characterized in that: The limiting structure comprises a fixing block (9), a displacement block (10), a pressing sheet (11) and a screw (12); A fixed block (9) is installed on the telecentric camera (6), displacement blocks (10) are installed on both sides of the fixed block (9), a pressing sheet (11) is installed on the displacement block (10), and screws (12) are installed on the displacement block (10) and the pressing sheet (11).

4. An autocollimator according to claim 3, characterized in that: The pressing sheet (11) and the displacement block (10) are provided with movable and adjustable cavities.

5. An autocollimator according to claim 4, characterized in that: The telecentric camera (6), beam splitter (7) and optical path plate (8) in the displacement structure (1) are used in conjunction with the lens to be tested (3), the four-dimensional stage (4) and the CMOS camera (5).

6. An autocollimator according to claim 5, characterized in that: The fixed block (9) can be adjusted and connected along the displacement blocks (10) on both sides.

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