Auto-collimator measurement rectangular prism structure and measurement method
By adding the second CCD to the self-collimator measurement structure and adjusting the beam incident angle, the problem that traditional self-collimator is difficult to separate the oblique reflected image from the right-angle reflective image when measuring a right-angle prism, achieving higher measurement accuracy.
Patent Information
- Application Number
- CN202510107093.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-23
- Publication Date
- 2025-06-10
AI Technical Summary
When measuring right-angle prisms, it is difficult to separate the oblique reflected image from the right-angle reflected image, resulting in an increase in measurement error and increased difficulty.
A self-collimator measurement structure is adopted, including an objective lens, a first CCD and a second CCD. By changing the incident angle of the light beam, the oblique reflective image of the right angle prism is projected on the second CCD, thereby achieving separation from the right angle reflective image.
By adding the second CCD and adjusting the incident angle of the light beam, the separation of the right-angle prism oblique reflective image and the right-angle reflective image is successfully achieved, and the measurement accuracy is improved.
Smart Images
Figure CN120122344A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of right-angle prism measurement, and particularly to a structure and a measurement method for measuring a right-angle prism by an autocollimator. Background Art
[0002] An autocollimator is an optical instrument that combines a collimator tube and a collimating telescopic system into one. It is based on the principle of optical autocollimation and is used to observe changes in the position of a target.
[0003] The development process of the autocollimator is visual type, photoelectric zero-indicating type, and digital display type. The early visual autocollimator completed measurements by human eye observation combined with a mechanical micrometer device, and the measurement accuracy was not high; the photoelectric zero-indicating type was a transitional stage, using analog photoelectric alignment, and the reading method was visual and manual, and the accuracy did not increase significantly. The current so-called photoelectric autocollimator refers to the digital display type. The autocollimator completes measurements through a photoelectric sensor, and the progress of photoelectric detector technology, semiconductor technology, and computer technology has greatly improved the accuracy of the photoelectric autocollimator.
[0004] The autocollimator is widely used in precision measurement fields such as straightness measurement, parallelism measurement, and indexing error inspection of indexing mechanisms: The autocollimator is used for various inspections or measurements, adjustments such as installation inspection of optical components such as mirrors or lenses, triangular prisms, etc., inspection of the swing or tilt of CD or DVD discs, assembly adjustment of pickers of CD devices or DVD devices, optical axis tilt adjustment of laser diodes, head tilt inspection of HDDs, parallelism measurement of CCD elements and protective glasses, tilt or parallelism measurement of various planes such as platforms or tabletops, components, etc.
[0005] A right-angle prism is often used to turn the optical path or deflect the image formed by an optical system by 90°, and can also be used for applications such as image combination and beam offset.
[0006] The right-angle prism itself has a relatively large contact area and typical angles such as 45° and 90°. Compared with ordinary mirrors, the right-angle prism is easier to install and has better stability and strength against mechanical stress. They are the best choice for optical components used in various devices and instruments.
[0007] The right-angle prism is a unidirectionally sensitive mirror. Using the right-angle prism as a reflector has the characteristic of being unidirectionally sensitive. Its manufacturing requirements and installation requirements are very high. In terms of manufacturing: an error in the 90° roof angle will produce double images in the pitch direction; the flatness error of the two reflecting surfaces, especially the bending of a relatively long right-angle prism, will cause azimuth errors when using different parts of the prism; in terms of installation: it is necessary to ensure the levelness of the edge line of the right-angle prism, otherwise azimuth errors will be caused during oblique aiming. The levelness of the edge line of the right-angle prism is a special optical characteristic when the right-angle prism is used as a reflector.
[0008] Among them, when a traditional autocollimator measures whether the included angle between the two right-angle sides of a right-angle prism meets the requirements, as Figure 1 shown, the light beam is vertically oriented towards the hypotenuse of the right-angle prism, so that the reflected image of the hypotenuse of the right-angle prism will be presented on the same CCD as the reflected images of the two right-angle sides and interfere with each other, thereby increasing the measurement error of the right-angle prism and increasing the measurement difficulty. Summary of the Invention
[0009] The technical problem to be solved by the present invention is: how to separate the reflected image of the hypotenuse of the right-angle prism from the reflected image of the right-angle side.
[0010] To solve the above technical problem, the technical solution adopted by the present invention is: One technical solution adopted by the present invention is: An autocollimator for measuring a right-angle prism structure includes an objective lens, a first CCD, and a second CCD; The objective lens has a beam splitter, the first CCD and the right-angle prism are respectively arranged on both sides of the beam splitter, and the hypotenuse of the right-angle prism faces the beam splitter; The second CCD faces the hypotenuse of the right-angle prism, and the optical path of the hypotenuse of the right-angle prism facing the second CCD forms an angle A with the optical path of the beam splitter facing the hypotenuse of the right-angle prism, and the A satisfies the condition:
[0011] Among them, D represents the diameter of the objective lens, and R represents the distance from the first CCD to the right-angle prism.
[0012] To solve the above technical problem, another technical solution adopted by the present invention is: The light source forms parallel light after being refracted by the objective lens; The parallel light is perpendicularly projected onto the hypotenuse of the right-angle prism, so that the reflected images of the hypotenuse and the right-angle sides of the right-angle prism are projected onto the first CCD; Taking the incident point of the parallel light on the hypotenuse of the right-angle prism as the rotation point, the right-angle prism is rotated so that the reflected image of the hypotenuse of the right-angle prism leaves the first CCD and is projected onto the second CCD; The included angle deviation B of the two right-angle sides of the right-angle prism is calculated by the paraxial geometric optical principle, and the included angle deviation B satisfies the condition:
[0013] Among them, d represents the distance from the reflected image of the right-angle side of the right-angle prism to the center point of the first CCD, and r is the distance from the first CCD to the first cemented lens.
[0014] The beneficial effects of the present invention are as follows: A second CCD is added. By changing the incident angle of the light beam on the right-angle prism, the reflected image of the hypotenuse of the right-angle prism is separated from the first CCD and projected onto the second CCD, realizing the separation of the reflected image of the hypotenuse and the reflected image of the right-angle side of the right-angle prism, thereby ensuring the measurement accuracy. Description of the Drawings
[0015] Figure 1 FIG. 6 is a schematic structural diagram of a traditional autocollimator for measuring a right-angle prism; Figure 2 FIG. 9 is a schematic structural diagram of an autocollimator for measuring a right-angle prism proposed by the present invention; Reference Numeral Description: 1, objective lens; 11, beam splitter; 12, reticle; 13, filter; 14, convex lens; 15, light homogenizer; 2, first CCD; 3, second CCD; 4, first cemented lens; 5, second cemented lens; 6, light source; 7, right-angle prism. Specific Embodiments
[0016] To describe in detail the technical content, achieved objectives and effects of the present invention, the following is described in conjunction with the embodiments and with reference to the drawings.
[0017] Please refer to Figure 2 As shown, an autocollimator for measuring a right-angle prism structure includes an objective lens 1, a first CCD 2, and a second CCD 3; the objective lens 1 has a beam splitter 11, the first CCD 2 and the right-angle prism 7 are respectively arranged on both sides of the beam splitter 11, and the hypotenuse of the right-angle prism 7 faces the beam splitter 11; the second CCD 3 faces the hypotenuse of the right-angle prism 7, and the optical path of the hypotenuse of the right-angle prism 7 facing the second CCD 3 forms an angle A with the optical path of the beam splitter 11 facing the hypotenuse of the right-angle prism 7, and the A satisfies the condition:
[0018] wherein, D represents the diameter of the objective lens 1, and R represents the distance from the first CCD 2 to the right-angle prism 7.
[0019] Working principle: The beam of light emitted by the light source 6 is refracted by the beam splitter 11 towards the right-angle prism 7. Since the optical path of the hypotenuse of the right-angle prism 7 facing the second CCD 3 forms an angle A with the optical path of the beam splitter 11 facing the hypotenuse of the right-angle prism 7, the reflected image of the hypotenuse of the right-angle prism 7 can be presented on the second CCD 3, and the reflected image of the right-angle side of the right-angle prism 7 can be presented on the first CCD 2. Thus, it is convenient to measure the reflected image of the right-angle side of the right-angle prism 7 on the first CCD 2.
[0020] Please refer to Figure 2 As shown, further, a first cemented lens 4 is arranged between the beam splitter 11 and the right-angle prism 7.
[0021] As can be seen from the above description, the first cemented lens 4 is used to reduce chromatic aberration to ensure the imaging quality on the CCD; and to make the light beam form parallel light and enter the right-angle prism 7 to ensure the measurement accuracy.
[0022] Please refer to Figure 2 As shown, further, a second cemented lens 5 is arranged between the second CCD 3 and the right-angle prism 7.
[0023] As can be seen from the above description, the second cemented lens 5 is used to reduce chromatic aberration and to make the light beam form parallel light and image on the second CCD 3 to ensure the measurement accuracy.
[0024] It should be noted that the distance from the first cemented lens 4 to the right-angle prism 7 is equal to the distance from the second cemented lens 5 to the right-angle prism 7 to ensure the imaging quality on the second CCD 3.
[0025] Please refer to Figure 2 As shown, further, the objective lens 1 further includes a reticle 12, and the reticle 12 projects a light beam towards the beam splitter 11. Preferably, the reticle 12 is a cross reticle.
[0026] As can be seen from the above description, using the reticle 12 can make the images on the first CCD 2 and the second CCD 3 take a specific shape for easy measurement.
[0027] It should be noted that the distance from the reticle 12 to the beam splitter 11 plus the distance from the beam splitter 11 to the first cemented lens 4 is equal to the distance from the second CCD 3 to the second cemented lens 5 to ensure that the reflected image of the hypotenuse of the right-angle prism 7 can be focused and imaged on the second CCD 3.
[0028] Please refer to Figure 2 As shown, further, the objective lens 1 further includes a filter 13, and the filter 13 is used to filter out monochromatic light and project it towards the beam splitter 11. Preferably, the filter 13 filters monochromatic light with a wavelength of 546 nm.
[0029] As can be seen from the above description, using the filter 13 to filter the white light emitted by the light source 6 into monochromatic light can avoid the light not being converted into parallel light due to chromatic aberration.
[0030] Please refer to Figure 2 As shown, further, the objective lens 1 further includes a convex lens 14, and the convex lens 14 is used to project parallel light towards the beam splitter 11.
[0031] As can be seen from the above description, using the convex lens 14 to convert the light beam into parallel light can ensure the measurement accuracy.
[0032] Please refer to Figure 2As shown, further, the objective lens 1 further includes a light homogenizing plate 15, and the light homogenizing plate 15 is located in the light-emitting direction of the convex lens 14.
[0033] As can be seen from the above description, the light homogenizing plate 15 is used to optimize the uneven beam distribution into a uniform state to ensure the measurement accuracy.
[0034] Embodiment 1 A self-collimator for measuring a right-angle prism structure, please refer to Figure 2 As shown, it includes a light source 6, an objective lens 1, a first CCD 2, and a second CCD 3; the objective lens 1 includes a filter 13, a convex lens 14, a light homogenizing plate 15, a reticle 12, and a beam splitter 11 arranged in sequence. The spherical white light emitted by the light source 6 passes through the filter 13, the convex lens 14, the light homogenizing plate 15, and the reticle 12 in sequence and is transformed into monochromatic parallel light. The first CCD 2 and the right-angle prism 7 are respectively arranged on both sides of the beam splitter 11, and the hypotenuse of the right-angle prism 7 faces the beam splitter 11; the second CCD 3 faces the hypotenuse of the right-angle prism 7, and the optical path of the hypotenuse of the right-angle prism 7 facing the second CCD 3 forms an angle A with the optical path of the beam splitter 11 facing the hypotenuse of the right-angle prism 7, and the A satisfies the condition:
[0035] wherein, D represents the diameter of the objective lens 1, and R represents the distance from the first CCD 2 to the right-angle prism 7.
[0036] A first cemented lens 4 is arranged between the beam splitter 11 and the right-angle prism 7. A second cemented lens 5 is arranged between the second CCD 3 and the right-angle prism 7. The distance from the first cemented lens 4 to the right-angle prism 7 is equal to the distance from the second cemented lens 5 to the right-angle prism 7. The distance from the reticle 12 to the beam splitter 11 plus the distance from the beam splitter 11 to the first cemented lens 4 is equal to the distance from the second CCD 3 to the second cemented lens 5.
[0037] Embodiment 2 A measurement method, the light source 6 is refracted by the objective lens 1 to form parallel light; the parallel light is perpendicularly projected onto the hypotenuse of the right-angle prism 7 so that the reflected images of the hypotenuse and the right-angle side of the right-angle prism 7 are projected onto the first CCD 2; taking the incident point of the parallel light on the hypotenuse of the right-angle prism 7 as the rotation point, the right-angle prism 7 is rotated so that the reflected image of the hypotenuse of the right-angle prism 7 leaves the first CCD 2 and is projected onto the second CCD 3; the angular deviation B of the two right-angle sides of the right-angle prism 7 is calculated by the paraxial geometric optics principle, and the angular deviation B satisfies the condition:
[0038] Wherein, d represents the distance from the reflected image of the right-angled side of the right-angled prism 7 to the center point of the first CCD 2, and r is the distance from the first CCD 2 to the first cemented lens 4. The rotation angle of the right-angled prism 7 is a, and the a satisfies the condition:
[0039] Wherein, D represents the diameter of the objective lens 1, and R represents the distance from the first CCD 2 to the right-angled prism 7.
[0040] The above are only embodiments of the present invention, and do not limit the patent scope of the present invention. Any equivalent transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in the related technical field, shall be included in the patent protection scope of the present invention by the same token.
Claims
1. An autocollimator for measuring a right-angle prism structure, characterized in that: It includes an objective lens, a first CCD, and a second CCD; The objective lens has a beam splitter, a first CCD and a right-angle prism are arranged on both sides of the beam splitter, and the hypotenuse of the right-angle prism faces the beam splitter; The second CCD faces the hypotenuse of the right-angle prism, and the light path from the hypotenuse of the right-angle prism to the second CCD forms an angle A with the light path from the beam splitter to the hypotenuse of the right-angle prism, and A satisfies the condition: Wherein, D represents the diameter of the objective lens, and R represents the distance from the first CCD to the right-angle prism.
2. The method for measuring a right-angle prism structure using an autocollimator according to claim 1, characterized in that: A first cemented mirror is arranged between the beam splitter and the right-angle prism.
3. The method for measuring a right-angle prism structure using an autocollimator according to claim 2, wherein: A second cemented mirror is arranged between the second CCD and the right-angle prism.
4. The method for measuring a right-angle prism structure using an autocollimator according to claim 3, wherein: The distance from the first cemented mirror to the right-angle prism is equal to the distance from the second cemented mirror to the right-angle prism.
5. The method for measuring a right-angle prism structure using an autocollimator according to claim 3, characterized in that: The objective lens also includes a graticule that projects the light beam toward the beam splitter.
6. The method for measuring a right-angle prism structure using an autocollimator according to claim 5, characterized in that: The distance from the graticule to the beam splitter plus the distance from the beam splitter to the first bonded mirror is equal to the distance from the second CCD to the second bonded mirror.
7. The method for measuring a right-angle prism structure using an autocollimator according to claim 1, characterized in that: The objective lens also includes a filter, which is used to filter out monochromatic light and project it to the beam splitter.
8. The method for measuring a right-angle prism structure using an autocollimator according to claim 1, characterized in that: The objective lens also includes a convex lens, which is used to project parallel light to the beam splitter.
9. A method for measuring a right-angle prism structure based on the autocollimator according to any one of claims 2 to 8, characterized in that: The light source is refracted by the objective lens to form parallel light; The parallel light is vertically projected onto the hypotenuse of the right-angle prism, so that the reflected images of the hypotenuse and the right-angle side of the right-angle prism are projected onto the first CCD; Taking the incident point of the parallel light on the hypotenuse of the right-angle prism as the rotation point, the right-angle prism is rotated so that the image reflected by the hypotenuse of the right-angle prism leaves the first CCD and is projected onto the second CCD; The angle deviation B of the two right-angle sides of the right-angle prism is calculated according to the paraxial geometric optical principle. The angle deviation B satisfies the condition: Wherein, d represents the distance from the reflected image of the right-angled side of the right-angle prism to the center point of the first CCD, and r represents the distance from the first CCD to the first cemented mirror.
10. The measuring method according to claim 9, characterized in that: The rotation angle of the right-angle prism is a, and a satisfies the condition: Wherein, D represents the diameter of the objective lens, and R represents the distance from the first CCD to the right-angle prism.