Right angle prism calibration device and calibration method

Abstract

The invention discloses a calibration device and calibration method for a right-angle prism, which are used to solve the calibration problem of whether the right-angle prism can meet the accuracy requirements after installation and clamping. The device comprises two autocollimators, a reflector and a right-angle prism group to be inspected, and the three parts are fixed on a base; the two autocollimators are respectively used to calibrate the angle difference between the incident light and the outgoing light of the right-angle prism, and the accuracy of the graticule determines the calibration accuracy of the device; the mounting surface of the reflector is at an angle of 45° to the horizontal plane, and its function is to convert the horizontal target image received by one of the autocollimators into a vertical image; the right-angle prism group to be inspected converts the vertical image reflected by the reflector through the reflection surface of its hypotenuse, and finally converts it into a horizontal image, so that the target image is formed on the graticule in another autocollimator. By using the device of the invention, the accuracy of the right-angle prism itself and the assembly accuracy of the right-angle prism can be quickly calibrated.

Description

Technical Field

[0001] The invention relates to the field of calibration of optical elements, and in particular to a calibration device and a calibration method for a right-angle prism. Background Art

[0002] Right-angle prisms are usually used to bend the light path or deflect the image formed by the optical system by 90°. One of the basic functions of right-angle prisms is to use the critical angle characteristics to efficiently reflect the incident light internally.

[0003] The right-angle prism itself has a larger contact area and typical angles such as 45° and 90°. Therefore, compared with ordinary reflectors, the right-angle prism is easier to install and has better stability and strength against mechanical stress.

[0004] There are professional detection methods for the detection of the angle of the right-angle prism itself, but the application of the right-angle prism often requires clamping. For the right-angle prism after clamping, the mounting surface becomes its reference, so whether the accuracy of the right-angle prism after clamping can still meet the use requirements requires a certain calibration device for inspection and auxiliary adjustment to meet the use requirements after clamping. Summary of the invention

[0005] In view of the lack of a calibration device in the prior art for checking whether a right-angle prism can meet the use requirements after being installed and clamped, the present invention provides a calibration device for a right-angle prism and a calibration method thereof, the purpose of which is to use the device to check the accuracy of the prism itself and to use the device to perform accuracy adjustment on the prism after assembly, and to greatly improve the efficiency of workpiece assembly and adjustment, and effectively ensure product quality.

[0006] The technical solution of the present invention is as follows:

[0007] A right-angle prism calibration device comprises a first autocollimator, a second autocollimator, a reflector, a right-angle prism group to be inspected, a base, a support, a connecting seat, a reflector seat, a first autocollimator support and a second autocollimator support; the first autocollimator and the second autocollimator are respectively connected to the first autocollimator support and the second autocollimator support and fixed to the two ends of the base; the support is an inner hollow structure, the reflector seat is located in the support, and the reflector is fixed on the reflector seat; the upper surface of the support is connected to the frame of the right-angle prism group to be inspected through the connecting seat, and the lower bottom surface is fixed to the middle part of the base through a cylindrical surface; the support is symmetrically provided with cutouts facing the front and back of the first autocollimator, and the size of the cutouts can ensure that all light passing through the first autocollimator is received by the reflector.

[0008] Furthermore, the first autocollimator and the second autocollimator adopt a double-graticule type autocollimation structure including an image graticule and a target graticule.

[0009] Furthermore, the spacing between the first autocollimator support and the second autocollimator support should be able to meet the requirement that after the first autocollimator and the second autocollimator are installed on the first autocollimator support and the second autocollimator support, the objective lens surfaces of the first autocollimator and the second autocollimator do not interfere with the right-angle surfaces of the nearest reflector and right-angle prism group and conform to ergonomics.

[0010] Furthermore, the height difference between the first autocollimator support and the second autocollimator support must be able to meet the requirement of being completely consistent with the distance between the internal reflection center of the right-angle prism group and the reflection center of the reflector, that is, the incident light and the outgoing light are completely parallel, thereby ensuring that the target image received by the first autocollimator / second autocollimator is imaged on the image graticule of the second autocollimator / first autocollimator.

[0011] Furthermore, the mounting surface of the reflector is at an angle of 45° to the horizontal plane, and its function is to convert the horizontal target image received by one of the two autocollimators into a vertical image, so the reflection center of the reflector must coincide with the center of the first autocollimator and coincide with the internal reflection center of the right-angle prism group.

[0012] Furthermore, the right-angle prism group to be inspected converts the vertical image reflected by the reflector into a horizontal image through the reflection of the inner reflection surface of the hypotenuse, thereby imaging the target on the image graticule in another autocollimator.

[0013] Furthermore, two square holes are opened on the two side surfaces of the support, which are used to adjust the reflector seat and fix the reflector seat on the base through a fourth screw.

[0014] Furthermore, the first autocollimator and the second autocollimator are fixed to the first autocollimator support and the second autocollimator support respectively by means of a second screw and a pressure head; the first autocollimator support and the second autocollimator support are further fixed to the base by means of a fifth screw.

[0015] Furthermore, the reflector is fixed to the reflector seat by a pressure plate and a sixth screw, and then fixed to the base by a fourth screw; the right-angle prism group to be inspected is connected to the connecting seat by a first screw, the connecting seat is connected to the support by a third screw, and the support is fixed to the base by a fourth screw.

[0016] Furthermore, the image graticule is provided with a plurality of concentric circles, each concentric circle corresponds to a detection accuracy, and the accuracy is inversely proportional to the radius of the concentric circle.

[0017] Furthermore, in the right-angle prism calibration device, after being reflected by the right-angle prism group and the reflector, the incident light is parallel to the outgoing light, thereby facilitating the detection of changes in the light after passing through the right-angle prism.

[0018] A calibration method for a right angle prism calibration device, wherein the autocollimator adopts a double-graticule autocollimation structure; the double autocollimators are viewed opposite to each other, and the right angle prism to be measured is regarded as a reflector. When the right angle prism has a deflection angle, the reflected image and the center image of the graticule do not coincide, and the read deviation value is the deflection angle of the right angle prism. The double-graticule autocollimator structure is composed of a plane reflector, an objective lens, a light analyzing prism, a target graticule, a frosted glass, a light source, an image graticule and an eyepiece.

[0019] Calibration methods include:

[0020] First, the right-angle prism is installed into the prism frame according to a given process method, the gap between the right-angle prism and the prism frame is filled with silicone rubber, and the prism group is locked on the connecting seat.

[0021] The illuminator in the first autocollimator is turned on, and the target graticule image is reflected by the reflector to the internal reflection surface of the right-angle prism group and then reflected back to the second autocollimator, forming an image on the image graticule of the second autocollimator. Alternatively, the illuminator in the second autocollimator can be turned on, and the light is reflected by the hypotenuse of the right-angle prism group, emitted from the other right-angle side, reflected by the reflector, received by the first autocollimator, and formed an image on the image graticule of the first autocollimator.

[0022] Regardless of which method is used, two images can be seen in the first autocollimator or the second autocollimator. If the two images overlap, it means that the outgoing light of the inspected prism group is perpendicular to the incident light after assembly, which meets the use requirements. If the two images in the two autocollimators do not overlap, the two images in the autocollimators can be adjusted to overlap by adjusting the adjustment screws on the prism group, that is, to ensure that the outgoing light of the assembled prism group is perpendicular to the incident light.

[0023] Compared with the prior art, the right-angle prism calibration device and calibration method of the present invention have the following beneficial effects:

[0024] 1. The positioning and clamping method consistent with the use status of the prism assembly is adopted to ensure the accuracy during use;

[0025] 2. Convenient and simple clamping, quick adjustment;

[0026] 3. By using the present invention, the accuracy of the prism itself can be checked and the accuracy of the prism after assembly can be adjusted by the device;

[0027] 4. By using the present invention, the efficiency of workpiece assembly and adjustment is greatly improved, and product quality is effectively guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a structural schematic diagram of the right-angle prism calibration device in the present invention.

[0029] Figure 2 yes Figure 1main view.

[0030] Figure 3 yes Figure 2 Section view along AA.

[0031] Figure 4 This is the schematic diagram of a double-graticule autocollimator.

[0032] Figure 5 This is the schematic diagram of the right-angle prism calibration device.

[0033] In the figure: 1a-first autocollimator, 1b-second autocollimator; 2-base; 3-support; 4-connecting seat; 5-reflector seat; 6-pressing plate; 7-first autocollimator support; 8-second autocollimator support; 9-first screw; 10-second screw; 11-pressing head; 12-reflector; 13-image dividing plate; 14-third screw; 15-fourth screw; 16-fifth screw; 17-sixth screw; 18-right-angle prism group to be tested; 19-plane reflector; 20-objective lens; 21-light-analyzing prism; 22-target dividing plate; 23-ground glass; 24-light source; 25-eyepiece. DETAILED DESCRIPTION

[0034] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention.

[0035] Example 1

[0036] like Figures 1 to 3 As shown, the right-angle prism calibration device of the present invention comprises two autocollimators, a first autocollimator 1a and a second autocollimator 1b, a reflector 12 and a right-angle prism group 18 to be inspected, wherein the first autocollimator 1a, the second autocollimator 1b, the reflector 12 and the right-angle prism group 18 to be inspected are all fixed on a base 2;

[0037] The first autocollimator 1a and the second autocollimator 1b are fixed to the first autocollimator support 7 and the second autocollimator support 8 by means of the second screw 10 and the pressure head 11 respectively; the first autocollimator support 7 and the second autocollimator support 8 are fixed to the base 2 by means of the fifth screw 16 and are respectively located at the two ends of the base 2;

[0038] The reflector 12 is fixed to the reflector seat 5 by means of the pressing plate 6 and the sixth screw 17, and then fixed to the base 2 by means of the fourth screw 15, and is located between the two autocollimators;

[0039] The right-angle prism group 18 to be inspected is connected to the connecting seat 4 through the first screw 9 , the connecting seat 4 is connected to the support 3 through the third screw 14 , and the support 3 is fixed to the base 2 through the fourth screw 15 .

[0040] The support 3 is a hollow structure, the reflector seat 5 is located inside the support 3, the upper surface of the support 3 is connected to the frame of the right-angle prism group 18 to be inspected through the connecting seat 4, and the lower bottom surface is fixed to the middle of the base 2 through the cylindrical surface. The support 3 is symmetrically provided with cutouts on the front and back sides facing the first autocollimator 1a, and the size of the cutouts can ensure that all the light passing through the first autocollimator 1a is received by the reflector 12. Two square holes are opened on the two sides of the support 3 for adjusting the reflector seat and fixing the reflector seat 5 on the base 2 through the fourth screw 15.

[0041] The spacing between the first autocollimator support 7 and the second autocollimator support 8 should be such that after the first autocollimator 1a and the second autocollimator 1b are installed on the first autocollimator support 7 and the second autocollimator support 8, the objective lens surfaces of the first autocollimator 1a and the second autocollimator 1b do not interfere with the nearest reflector 12 and the right-angle surface of the right-angle prism group and conform to ergonomics; the height difference between the first autocollimator support 7 and the second autocollimator support 8 should be such that the distance between the internal reflection center of the right-angle prism group 18 and the reflection center of the reflector 12 is completely consistent, that is, the incident light and the outgoing light are completely parallel, so as to ensure that the target image received by the first autocollimator 1a / the second autocollimator 1b is formed on the image graticule 13 of the second autocollimator 1b / the first autocollimator 1a;

[0042] The mounting surface of the reflector 12 is at an angle of 45° to the horizontal plane. Its function is to convert the horizontal target image received by one of the two autocollimators into a vertical image. Therefore, the reflection center of the reflector 12 must coincide with the center of the first autocollimator 1a and the internal reflection center of the right-angle prism group 18.

[0043] The right-angle prism group 18 to be inspected converts the vertical image reflected by the reflector 12 into a horizontal image through the reflection surface inside the hypotenuse, thereby imaging the target on the image graticule 13 in another autocollimator.

[0044] In this embodiment, the third screw 14 is M3×12, the fourth screw 15 is M5×12, the fifth screw 16 is M5×20, and the sixth screw 17 is M2×5.

[0045] The working principle of the right-angle prism calibration device of the present invention is as follows:

[0046] like Figure 4 As shown, the first autocollimator 1a / second autocollimator 1b described in the present invention can adopt commercially available double-graticule products, such as the products of Northern Optoelectronics.

[0047] The double-graticule autocollimator is composed of a plane reflector 19, an objective lens 20, a light-analyzing prism 21, a target graticule 22, a frosted glass 23, a light source 24, an image graticule 13 and an eyepiece 25.

[0048] Working principle of double-graticule autocollimator: light source 24 illuminates frosted glass 23, becoming a uniform light source, illuminating target graticule 22, and the graticule lines on target graticule 22 emit light, which is reflected by the light separation surface of light separation prism 21 and emitted by objective lens 20 as a parallel imaging beam. The parallel light is reflected back to objective lens 20 by plane reflector 19 and becomes convergent light. The convergent light beam passes through the light separation surface of light separation prism 21 and is focused on image graticule 13, that is, the graticule lines on target graticule 22 are imaged on image graticule 13.

[0049] Assuming the rear focal length of the objective lens is f', when the plane mirror rotates α, the image shift y is:

[0050] y=f′tg2α

[0051] The calibration device of the right-angle prism is designed to be a double autocollimator, and the right-angle prism to be measured is regarded as a reflector. When the right-angle prism has a deflection angle, the reflected image and the center image of the image dividing plate 13 will not coincide, and the deviation value read out is the deflection angle of the right-angle prism.

[0052] Figure 5 The schematic diagram of the right angle prism calibration device is shown in FIG. The device adopts the principle of autocollimation and is mainly composed of two autocollimators (the first autocollimator 1a and the second autocollimator 1b), the right angle prism 18 to be inspected, and the reflector 12.

[0053] The principle of the right-angle prism calibration device: after the target emits light, the light received by one of the autocollimator tubes is reflected by the reflector 12, and the light is reflected to the reflection surface of the right-angle prism group 18 to be tested, and then reflected by the internal reflection surface of the right-angle prism group 18 to be tested, the target image is formed on the image graticule 13 of another autocollimator.

[0054] The right-angle prism calibration device of the present invention is mainly used for the assembly accuracy of the right-angle prism itself relative to the prism frame after the right-angle prism is assembled in the prism frame.

[0055] Specific usage method: first, install the right-angle prism into the prism frame according to a given process method, fill the gap between the right-angle prism and the prism frame with silicone rubber, and lock the prism group 18 on the connecting seat 4 through two first screws 9 according to the assembly direction in the figure.

[0056] Will Figure 5 The illumination lamp in the first autocollimator 1a is turned on, and the target graticule image is reflected by the reflector 12 to the internal reflection surface of the right-angle prism group 18 and then reflected back to the second autocollimator 1b, forming an image on the image graticule 13 of the second autocollimator 1b. Alternatively, Figure 5The lighting lamp in the second autocollimator 1b is turned on, and the light is reflected by the hypotenuse of the right-angle prism group 18, emitted from the other right-angle side, reflected by the reflector 12, received by the first autocollimator 1a, and imaged on the image graticule 13 of the first autocollimator 1a.

[0057] Regardless of which method is used, two images can be seen in the first autocollimator 1a or the second autocollimator 1b. If the two images overlap, it means that the outgoing light of the inspected prism group is perpendicular to the incident light after assembly, which meets the use requirements. If the two images in the two autocollimators do not overlap, the two images in the autocollimators can be adjusted to overlap by adjusting the adjustment screws on the prism group, that is, to ensure that the outgoing light of the assembled prism group is perpendicular to the incident light.

[0058] The assembly accuracy requirement for a right-angle prism assembly is: ±30'. Therefore, the image graticule 13 of the designed right-angle prism detection device is designed to be three concentric circles, and the detection accuracy corresponds to ±5', ±15', and ±25' respectively.

[0059] For example: The calculation method of the reticle diameter d1 corresponding to the accuracy of ±5′ is:

[0060] According to d1=y=f′tg2α, it is known that the focal length of the selected autocollimator is f′=140.91 mm, α=5′ / 60′≈0.083°, then d1=140.91×tg(2×0.083)≈0.41 mm. That is, the accuracy of the circle with a diameter of 0.41 mm on the image graticule 13 is ±5′.

[0061] Similarly, if higher precision is required, it can be achieved by redesigning the corresponding image grating plate 13.

[0062] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A right angle prism calibration device, characterized in that: It comprises a first autocollimator (1a), a second autocollimator (1b), a reflector (12), a right-angle prism group to be inspected (18), a base (2), a support (3), a connecting seat (4), a reflector seat (5), a first autocollimator support (7) and a second autocollimator support (8); The first autocollimator (1a) and the second autocollimator (1b) are respectively connected to a first autocollimator support (7) and a second autocollimator support (8) and are fixed to two ends of the base (2); The support (3) is a hollow structure, the reflector seat (5) is located inside the support (3), and the reflector (12) is fixed on the reflector seat (5); The upper surface of the support (3) is connected to the frame of the right-angle prism group (18) to be inspected via a connecting seat (4), and the lower bottom surface is fixed to the middle of the base (2) via a cylindrical surface; The support (3) is symmetrically provided with cutouts on the front and back sides facing the first autocollimator (1a), and the size of the cutouts can ensure that all light passing through the first autocollimator (1a) is received by the reflector (12); The first autocollimator (1a) and the second autocollimator (1b) are fixed to the first autocollimator support (7) and the second autocollimator support (8) respectively by means of a second screw (10) and a pressure head (11); the first autocollimator support (7) and the second autocollimator support (8) are further fixed to the base (2) by means of a fifth screw (16); The reflector (12) is fixed to the reflector seat (5) via a pressure plate (6) and a sixth screw (17), and is then fixed to the base (2) via a fourth screw (15); The right-angle prism group (18) to be inspected is connected to the connecting seat (4) via a first screw (9), the connecting seat (4) is connected to the support (3) via a third screw (14), and the support (3) is fixed to the base (2) via a fourth screw (15).

2. The right-angle prism calibration device according to claim 1, characterized in that: The first autocollimator (1a) and the second autocollimator (1b) are autocollimators of a double-graticule type self-collimation structure including an image graticule (13) and a target graticule (22).

3. The right-angle prism calibration device according to claim 2, characterized in that: The spacing between the first autocollimator support (7) and the second autocollimator support (8) is such that after the first autocollimator (1a) and the second autocollimator (1b) are mounted on the first autocollimator support (7) and the second autocollimator support (8), the objective lens surfaces of the first autocollimator (1a) and the second autocollimator (1b) do not interfere with the nearest reflective mirror (12) and the right-angle surface of the right-angle prism group, and the arrangement is ergonomic.

4. The right-angle prism calibration device according to claim 2, characterized in that: The height difference between the first autocollimator support (7) and the second autocollimator support (8) must be able to meet the requirement of being completely consistent with the distance between the internal reflection center of the right-angle prism group (18) and the reflection center of the reflector (12), that is, the incident light and the outgoing light are completely parallel, thereby ensuring that the target image received by the first autocollimator (1a) / the second autocollimator (1b) is imaged on the image graticule (13) of the second autocollimator (1b) / the first autocollimator (1a).

5. The right angle prism calibration device according to claim 2, characterized in that: The mounting surface of the reflector (12) is at an angle of 45° to the horizontal plane, and its function is to convert the horizontal target image received by one of the two autocollimators into a vertical image, so the reflection center of the reflector (12) must coincide with the center of the first autocollimator (1a) and coincide with the internal reflection center of the right-angle prism group (18).

6. The right angle prism calibration device according to claim 2, characterized in that: The right-angle prism group (18) to be inspected further converts the vertical image reflected by the reflector (12) into a horizontal image through the reflection surface inside the hypotenuse thereof, thereby imaging the target on an image graticule (13) in another autocollimator.

7. The right-angle prism calibration device according to any one of claims 1 to 6, characterized in that: Two square holes are formed on the two side surfaces of the support (3) for adjusting the reflector seat and fixing the reflector seat (5) on the base (2) via a fourth screw (15).

8. The right-angle prism calibration device according to any one of claims 2 to 6, characterized in that: The image graticule (13) is provided with a plurality of concentric circles, each concentric circle corresponds to a detection accuracy, and the accuracy is inversely proportional to the radius of the concentric circle.

9. A right-angle prism calibration method according to a right-angle prism calibration device according to any one of claims 1 to 8, characterized in that: The following steps are involved: (1) Install the right-angle prism into the prism frame, fill the gap between the right-angle prism and the prism frame with silicone rubber, and lock the prism assembly (18) on the connecting seat (4); (2) lighting the illumination lamp in the first autocollimator (1a), and reflecting the target graticule image through the reflector (12) to the internal reflection surface of the right-angle prism group (18) and then reflecting back to the second autocollimator (1b), forming an image on the image graticule plate (13) of the second autocollimator (1b); Alternatively, the illumination lamp in the second autocollimator (1b) is turned on, and the light is reflected by the hypotenuse of the right-angle prism group (18), emitted from the other right-angle side, reflected by the reflector (12), received by the first autocollimator (1a), and imaged on the image graticule (13) of the first autocollimator (1a); (3) If the two images seen in the first autocollimator (1a) or the second autocollimator (1b) overlap, then the outgoing light of the inspected prism group is perpendicular to the incident light after assembly, which meets the use requirements; if the two images in the two autocollimators do not overlap, proceed to the next step; (4) By adjusting the adjustment screws on the prism assembly, the two images in the autocollimator are aligned, that is, the outgoing light of the assembled prism assembly is ensured to be perpendicular to the incident light.

Images