High-coaxiality laser designator for interferometer and self-calibration method

Abstract

The invention discloses a high-coaxiality laser designator for an interferometer and a self-calibration method, which are used for solving the technical problem that the light emitting direction of the existing laser designator is inconsistent with the optical axis of the interferometer. The laser designator comprises a substrate, a laser light source, a two-dimensional adjusting frame and a plane mirror, the laser light source is fixed on one side of the substrate through the two-dimensional adjusting frame, the plane mirror is accurately positioned on the other side of the substrate, and an included angle of 90 degrees + / -4 degrees is formed between the mirror surface of the plane mirror and the initial emergent direction of laser. The original self-calibration method comprises the following steps: firstly, establishing a reference light path by using an auxiliary reflector, then adjusting a plane reflector to be vertical to the optical axis of the interferometer, and finally finely adjusting the laser emitting direction to be strictly coaxial with the optical axis of the interferometer. According to the method, alignment of second-level angle precision and submillimeter-level eccentric precision is achieved, the method is particularly suitable for optical adjustment and detection of large-aperture interferometers and invisible light interferometers, the adjustment efficiency and the measurement reliability are remarkably improved, and meanwhile the problems that in a traditional method, operation is complex, calibration is difficult and the like are solved.

Description

Technical Field

[0001] The present invention relates to the field of optical measurement and precision instrument technology, specifically a high-coaxiality laser pointer and self-calibration method for interferometers. The device is intended for high-precision optical measurement scenarios, including but not limited to interferometer optical axis alignment, high-coaxiality adjustment of optical components (or systems), and wavefront error detection. It is particularly suitable for large-aperture (over 300 mm) interferometers and invisible light interferometers. Background Art

[0002] As a high-precision optical inspection instrument, the interferometer plays a key role in the wavefront measurement of plane, spherical and aspheric optical components, optical system assembly and inspection, and other fields. As an important auxiliary tool for the interferometer, the laser pointer can quickly guide the posture adjustment of the optical component (or system) under test by emitting a visible laser beam, ensuring that the optical component (or system) under test is precisely aligned with the optical axis of the interferometer. It is especially suitable for long-distance rapid posture adjustment and high-precision optical assembly. For the component alignment operation before large-aperture (Φ300mm or more) interferometer measurement, if there is no assistance from the laser pointer, the operator is very likely to fall into the dilemma of "losing direction", and it is difficult to complete the precise alignment of the large-aperture standard mirror and the large-aperture component under test in a short time by random swinging.

[0003] However, currently available interferometer laser pointers (such as those from Zygo, a US company) have significant limitations: due to the random initial position of the interferometer's standard mirror adjustment mount, the laser pointer's light output direction is difficult to maintain strict coaxiality with the interferometer's output beam, making it impossible to accurately represent the interferometer's actual light output direction. This problem is particularly prominent in submillimeter eccentricity adjustment and wavefront detection of spherical optical components. For non-visible light interferometers, such as infrared interferometers, the lack of a high-precision laser pointer can further deprive operators of directional reference.

[0004] Existing technologies have yet to offer effective solutions to these problems. Some attempts have attempted to achieve coaxiality through mechanical fixation or rough calibration, but these efforts are limited by adjustment accuracy and environmental stability, making it difficult to meet the requirements for second-level coaxiality and submillimeter eccentricity. Furthermore, the alignment of invisible light interferometers remains highly dependent on operational experience, resulting in significant subjectivity and poor repeatability.

[0005] Therefore, there is an urgent need for a technical solution that can achieve high coaxiality laser indication and support rapid self-calibration to solve the problems of missing directional reference, low calibration efficiency, and complex operation in traditional interferometer installation and adjustment, thereby improving the reliability and efficiency of optical measurement. Summary of the Invention

[0006] In order to overcome the problem of the above-mentioned prior art laser pointer that the laser indication direction is inconsistent with the interferometer light output direction, making it difficult to achieve high-coaxial laser indication, the present invention provides a high-coaxial laser pointer and self-calibration method for an interferometer, which can ensure that the outgoing light beam of the laser pointer is strictly coaxial with the outgoing light beam of the interferometer, significantly improve the alignment accuracy and installation convenience of optical elements (or systems) in the external optical path of the interferometer, and fundamentally improve the installation and detection efficiency and measurement reliability of the external optical path of the interferometer.

[0007] The technical solutions of the present invention are as follows:

[0008] A high coaxiality laser pointer for an interferometer is characterized by comprising:

[0009] A base plate, with standard mirror interfaces provided around it for directly mounting on the bayonet of an interferometer standard mirror adjustment frame (201);

[0010] The laser light source module is fixedly mounted on a two-dimensional adjustment frame, and the two-dimensional adjustment frame is fixed to the center position of one side of the substrate through a rigid connection;

[0011] a plane reflector fixed at the center of the other side surface of the substrate, with its mirror surface facing opposite to the light emitting direction of the laser light source;

[0012] A switch and a power supply are electrically connected to the laser light source module and are used to control the on and off of the laser;

[0013] The plane reflector has an aperture of no less than 5 mm, a peak-to-valley value of a surface error of no more than 1 μm, and forms an angle of 90°±4° with the initial emission direction of the laser light source.

[0014] The operating wavelength of the laser light source is in the visible light band;

[0015] The pitch and yaw adjustment range of the two-dimensional adjustment frame is ±4°;

[0016] The power supply includes but is not limited to a switching power supply, a power adapter and a battery;

[0017] The self-calibration method is performed by using the above device to ensure that the light output direction of the laser pointer is consistent with the light output direction of the interferometer. The self-calibration method includes the following steps:

[0018] 1) placing an interferometer on a workbench, placing an auxiliary reflector at a distance of 5 m or more from the light emitting direction of the interferometer, and adjusting the pitch and yaw of the auxiliary reflector to adjust the light point reflected by the auxiliary reflector to the center of the crosshairs of the interferometer's point-to-point image. At this time, the light emitting direction of the interferometer is perpendicular to the surface of the auxiliary reflector;

[0019] 2) Mounting the device of the present invention on the bayonet of the interferometer standard mirror adjustment frame, and adjusting the pitch and yaw postures of the interferometer standard mirror adjustment frame to adjust the light spot reflected by the plane reflector to the center of the crosshairs of the interferometer's point-of-sight image. At this time, the light output direction of the interferometer is perpendicular to the plane reflector surface;

[0020] 3) Turning on the switch to cause the laser light source to emit an indicator beam, which is then reflected by the auxiliary reflector to form a laser spot near the laser light source;

[0021] 4) by adjusting the pitch and yaw postures of the two-dimensional adjustment frame, the laser light spot is moved to the center of the laser light source outlet, at which time the emission direction of the laser light source is perpendicular to the mirror surface of the auxiliary reflector;

[0022] 5) From the conclusions of steps 1), 2) and 4), it can be concluded that: the emission direction of the laser light source is also perpendicular to the surface of the plane reflector; the emission beam of the laser light source is coaxial with the emission beam of the interferometer (i.e., the two beams are parallel and concentric); at this point, the laser pointer completes self-calibration.

[0023] The technical effects of the present invention are as follows:

[0024] 1) By precisely calibrating the verticality of the laser pointer's light-emitting direction and the plane reflector on its back, it is ensured that when the plane reflector on its back is perpendicular to the interferometer's light-emitting direction, the laser pointer's outgoing beam is strictly coaxial with the interferometer's outgoing beam. This technical solution solves the problem that the laser pointers currently available on the market for interferometers (represented by products from the US company Zygo) cannot accurately represent the interferometer's actual light-emitting direction. It significantly improves the alignment accuracy and ease of adjustment of optical components (or systems) in the interferometer's external optical path, fundamentally resolving the technical difficulties in the traditional interferometer's optical path adjustment process. It not only significantly improves detection efficiency, but also effectively improves measurement reliability by ensuring beam coaxiality, providing a high-precision, high-efficiency solution for the field of precision optical measurement.

[0025] 2) The laser beam emitted by the device of the present invention can establish a high-precision optical axis reference in large-aperture, long-distance optical systems, effectively solving the positioning ambiguity problem caused by the inability of the light beam to return to the interferometer in traditional measurements, avoiding the tedious process of operators repeatedly adjusting the component posture, and improving the overall detection efficiency. For invisible light interferometers, the device overcomes the difficulty of adjusting the coaxiality of the optical path caused by the inability to visually calibrate, and reduces the workload of operators. In terms of the adjustment and detection of spherical optical components, the high-coaxiality laser indication can quickly and accurately locate the center of the sphere, effectively reducing adjustment errors, and providing reliable technical support for the rapid and accurate assembly of precision optical systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a side cross-sectional schematic diagram of the internal structure of the high coaxiality laser pointer used in the interferometer of the present invention;

[0027] Figure 2 The invention relates to a self-calibration process of a high coaxiality laser pointer and a self-calibration method for an interferometer;

[0028] Figure 3 The invention uses a high coaxiality laser pointer for an interferometer after self-calibration to complete the coaxial alignment of the interferometer light output direction and the lens element on an interferometer;

[0029] Figure 4 The invention uses a self-calibrated high coaxiality laser pointer for an interferometer to complete the vertical adjustment of the interferometer light output direction and the surface of the plane component to be measured on a large-aperture interferometer.

[0030] Figure 5 This is a physical reference diagram produced based on a high coaxiality laser pointer and a self-calibration method for an interferometer according to the present invention. DETAILED DESCRIPTION

[0031] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0032] See also Figure 1 , Figure 1It is a side cross-sectional schematic diagram of the internal structure of the high coaxiality laser pointer for the interferometer of the present invention. As can be seen from the figure, the high coaxiality laser pointer for the interferometer of the present invention comprises: the device 100 of the present invention, a substrate 101, a laser light source 102, a two-dimensional adjustment frame 103, a switch 104, a power supply 105 and a plane reflector 106; the laser light source 102 is fixed on the two-dimensional adjustment frame 103, and the two-dimensional adjustment frame 103 is fixed to the side center of the substrate 101; the laser light source 102 is connected to the switch 104 and the power supply 105 to form a series circuit; the plane reflector 106 is fixed to the other side center of the substrate 101, facing the laser light source 102. The light emitting direction of the source 102 is opposite; the substrate 101 is provided with standard mirror interfaces of the interferometer on all four sides and can be directly mounted on the bayonet of the interferometer standard mirror adjustment frame 201; the operating wavelength of the laser light source 102 is in the visible light band; the angle between the initial emission direction of the laser light source 102 and the mirror surface of the plane reflector 106 is 90°±4°; the pitch and yaw adjustment range of the two-dimensional adjustment frame 103 is ±4°; the power supply 105 includes but is not limited to a switching power supply, a power adapter and a battery; the aperture of the plane reflector 106 is not less than 5 mm, and the peak-to-valley value of the surface error is not greater than 1 μm.

[0033] Figure 2 The self-calibration method is to use the above device to achieve the consistency between the light output direction of the laser pointer and the light output direction of the interferometer. The self-calibration method is characterized in that it includes the following steps:

[0034] 1) If Figure 2 As shown in (a), an interferometer 200 is placed on a workbench, and an auxiliary reflector 202 is placed at a distance of 5 m or more from the light emitting direction of the interferometer 200. By adjusting the pitch and yaw of the auxiliary reflector 202, the light spot reflected by the auxiliary reflector 202 is adjusted to the center of the crosshairs of the interferometer 200's point-of-sight image 203. At this time, the light emitting direction of the interferometer 200 is perpendicular to the mirror surface of the auxiliary reflector 202.

[0035] 2) If Figure 2 As shown in FIG. 2( b ), the device of the present invention is mounted on the bayonet of the interferometer standard mirror adjustment frame 201. By adjusting the pitch and yaw of the interferometer standard mirror adjustment frame 201, the light spot reflected by the plane mirror 106 is adjusted to the center of the crosshairs of the interferometer 200's point-of-sight image 203. At this time, the light output direction of the interferometer 200 is perpendicular to the plane mirror 106.

[0036] 3) If Figure 2As shown in (c), the switch 104 is turned on, so that the laser light source 102 emits an indicator beam, which is then reflected by the auxiliary reflector 202 and forms a laser spot near the laser light source 102;

[0037] 4) If Figure 2 As shown in (c), by adjusting the pitch and yaw postures of the two-dimensional adjustment frame 103, the laser light spot is moved to the center of the light outlet of the laser light source 102. At this time, the emission direction of the laser light source 102 is perpendicular to the mirror surface of the auxiliary reflector 202;

[0038] 5) From the conclusions of steps 1), 2), and 4), it can be concluded that the emission direction of the laser light source 102 is also perpendicular to the mirror surface of the plane reflector 106, and the emission beam of the laser light source 102 is coaxial with the emission beam of the interferometer 200 (i.e., the two beams are parallel and concentric); at this point, the laser pointer completes self-calibration.

[0039] Example 1, Figure 3 In Example 1 of the present invention, the device of the present invention is installed on the bayonet of the interferometer standard mirror adjustment frame 201. By adjusting the pitch and yaw postures of the interferometer standard mirror adjustment frame 201, the light spot reflected by the plane reflector 106 is adjusted to the center of the crosshairs of the point-to-point image 203 of the interferometer 200. The installed lens element 204 is placed in the light-emitting direction of the interferometer. By adjusting the four-dimensional posture of the lens element 204, the two laser light spots reflected by the centers of the front and rear surfaces of the lens element 204 are moved to the center of the light outlet of the laser light source 102. At this time, after the device of the present invention is removed from the interferometer 200, the outgoing light beam of the interferometer 200 is coaxial with the optical axes of the front and rear surfaces of the lens element 204, and the coaxial angle error can reach the second level, and the coaxial eccentricity error can reach the sub-millimeter level.

[0040] Example 2, Figure 4 In Example 2 of the present invention, in a high-precision alignment application for large-aperture optical elements, the device of the present invention is mounted on the bayonet of the interferometer standard mirror adjustment mount 201. By adjusting the pitch and yaw postures of the interferometer standard mirror adjustment mount 201, the light spot reflected by the mirror surface of the plane reflector 106 is adjusted to the center of the crosshairs of the alignment screen 203 of the interferometer 200. The plane element 205 to be measured is placed in the light-emitting direction of the interferometer. By adjusting the pitch and yaw postures of the plane element 205, the laser light spot reflected by the surface of the plane element 205 is moved to the center of the light outlet of the laser light source 102. At this time, after the device of the present invention is removed from the interferometer 200, the outgoing light beam of the interferometer 200 is perpendicular to the mirror surface of the plane element 205, and the perpendicularity can reach the second level.

[0041] Example 3, Figure 5 This is Example 3 of the present invention, a real reference diagram of a high-coaxiality laser pointer for an interferometer manufactured based on the content of the present invention.

[0042] Experiments have shown that the device of the present invention is suitable for the requirements of second-level coaxiality and sub-millimeter eccentricity adjustment. It has strong versatility and is suitable for various types of optical elements such as plane and spherical surfaces, as well as interferometer systems with different calibers and different working wavelengths. In addition, the output laser provided by the device of the present invention has real-time visual feedback, which solves the problems of small alignment field and difficult blind adjustment of large-aperture components (and invisible light interferometers). In short, the indicator light beam emitted by the device of the present invention can simulate the direction of the optical axis of the interferometer. Through the assistance of visible light, it can not only achieve high coaxiality and efficient point-to-point operation, but also effectively avoid the risk of the operator's eyes being exposed to the interferometer output laser for a long time due to observation needs, significantly reducing the occupational health risks of laser detection equipment and achieving a perfect combination of safety, ease of operation and accuracy.

Claims

1. A high coaxiality laser pointer for an interferometer, characterized in that: include: A base plate (101) is provided with standard mirror interfaces on its periphery for being directly mounted on the bayonet of the interferometer standard mirror adjustment frame (201); A laser light source module (102) is fixedly mounted on a two-dimensional adjustment frame (103), wherein the two-dimensional adjustment frame (103) is fixed to a central position of a side surface of the substrate (101) through a rigid connection; a plane reflective mirror (106) fixed at the center of the other side surface of the substrate (101), with its mirror surface facing in the opposite direction to the light emitting direction of the laser light source (102); A switch (104) and a power supply (105) are electrically connected to the laser light source module (102) and are used to control the on and off of the laser; The plane reflector (106) has an aperture of not less than 5 mm, a peak-to-valley value of a surface error of not more than 1 μm, and forms an angle of 90°±4° with the initial emission direction of the laser light source (102).

2. The laser pointer according to claim 1, characterized in that The connection interface between the substrate (101) and the interferometer standard mirror adjustment frame (201) adopts a rapid positioning structure, ensuring that the installation repeat positioning accuracy is better than 0.05 mm.

3. A self-calibration method for the laser pointer according to claim 1 or 2, characterized in that: The following steps are involved: S1. An auxiliary reflector (202) is set 5 m outside the light-emitting direction of the interferometer (200), and the posture of the auxiliary reflector is adjusted so that the reflected light spot is precisely aligned with the center of the crosshairs of the interferometer point screen (203) to establish a reference light path; S2. Mounting the laser pointer on the interferometer standard mirror adjustment frame (201), and adjusting the light spot reflected by the plane reflector (106) to the center of the crosshairs of the interferometer (200) through the pitch and yaw of the interferometer standard mirror adjustment frame (201), so that the light emitting direction of the interferometer (200) is perpendicular to the plane reflector (106); S3. Turn on the laser light source (102) and observe the position of the laser spot returned by the auxiliary reflector (202); S4 finely adjust the pitch and yaw angles of the two-dimensional adjustment frame (103) so that the return light spot coincides with the center of the laser light outlet; S5. Lock all adjustment mechanisms to complete the strict coaxial calibration of the laser indication direction and the interferometer optical axis.

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