Dual-purpose detection interference device with visual observation and CCD display and detection method thereof

Abstract

This invention relates to the field of optical component processing technology, specifically providing a detection interference device that combines visual observation and CCD display. The device includes a detection stage, on which are mounted a laser, a condenser lens assembly, a beam splitter, a collimating objective lens, a wedge lens, an eyepiece beam splitter, an eyepiece, and a CCD camera. The condenser lens assembly is located above the laser, the beam splitter is positioned to the side of the laser and below the condenser lens assembly, the collimating objective lens and the wedge lens are located between the beam splitter and the optical lens to be tested, the horizontal center line connecting the eyepiece beam splitter and the eyepiece is collinear with the horizontal center line of the beam splitter, and the CCD camera is located above the eyepiece beam splitter. This invention also provides a detection method that combines visual observation and CCD display. This invention is designed for the application scenario of detecting optical components, offering the advantages of convenient visual observation operation, while simultaneously allowing for rapid and accurate reading of interference image information via a CCD camera. It is less affected by environmental conditions and has high applicability.

Description

Technical Field

[0001] This invention relates to the field of optical component processing technology, and in particular to a detection interference device and its detection method that can be used for both visual observation and CCD display. Background Technology

[0002] The processing of optical components generally involves multiple stages such as milling, grinding, and polishing. For manufacturers of optical components, the ability to quickly detect surface errors of optical components during the processing is a crucial step and a key factor in determining whether the entire processing can achieve high precision.

[0003] Currently, commonly used methods for detecting the surface shape error of plane mirrors include contact measurement methods and non-contact measurement methods. Contact measurement typically uses the glass template method, which involves aligning the standard surface of the template with the surface to be inspected of the part and applying pressure. The shape, number, and direction of movement of interference fringes are used to determine the surface shape error of the optical part. Non-contact measurement typically uses older visual interferometers, such as laser plane interferometers. Operators visually estimate the number and deformation of interference fringes to obtain the surface shape error of the plane mirror under test. The advantage of the glass template method is its ease of operation and simplicity. However, contact measurement is prone to wearing down the standard surface of the plane mirror under test, and the measurement error increases with the number of uses. While non-contact measurement does not have the problem of standard surface wear, the reading error is closely related to the operator's skill level, and the general estimation accuracy is 1 / 10λ, making it difficult to guarantee the accuracy of the measurement.

[0004] To avoid the aforementioned problems, some laboratories and research institutes have begun to use digital interferometers to perform higher-precision surface shape detection on planar optical components. However, digital interferometers are relatively expensive and have high requirements for the operating environment, which is not conducive to large-scale promotion.

[0005] In summary, for applications involving the inspection of optical components, designing an inspection interferometer and its testing method that combines the advantages of convenient visual observation with the ability to quickly and accurately read surface information from interferometric images is a pressing issue that needs to be addressed. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a detection interference device and method that combines visual observation and CCD display, integrating the advantages of both visual observation and CCD display. This reduces detection costs, lowers environmental requirements, and improves detection accuracy and applicability.

[0007] To achieve the above objectives, the present invention proposes the following technical solution: a detection interferometer device that combines visual observation and CCD display, comprising a detection stage, a laser and a condenser lens group located above the laser on the detection stage, the central axis of the condenser lens group being perpendicular to the optical axis of the laser; a beam splitter prism located below the condenser lens group on the side of the laser; a coaxial interferometer group located below the beam splitter prism, the optical lens to be tested being placed within the receiving area of ​​the detection stage and located below the interferometer group; a visual observation lens group and a CCD camera are located on the side of the beam splitter prism away from the laser, the horizontal center line of the visual observation lens group being collinear with the horizontal center line of the beam splitter prism, and the CCD camera being located above the visual observation lens group.

[0008] Preferably, the visual observation lens group includes an eyepiece beam splitter and an eyepiece arranged sequentially on the side of the beam splitter prism, through which the human eye observes; the horizontal center line connecting the eyepiece beam splitter and the eyepiece is collinear with the horizontal center line of the beam splitter prism; and the CCD camera is located above the eyepiece beam splitter.

[0009] Preferably, the beam splitter is formed by gluing together an upper triangular pyramid and a lower triangular pyramid arranged symmetrically, with the gluing surface of the upper and lower triangular pyramids serving as the beam splitting surface of the beam splitter; the cone surface of the upper triangular pyramid serves as the incident surface of the beam splitter, and the cone surface of the lower triangular pyramid serves as the exit surface of the beam splitter.

[0010] Preferably, the angle between the beam-splitting surface of the beam-splitting prism and the horizontal plane is 45°.

[0011] Preferably, the beam-splitting surface of the eyepiece beam splitter is arranged parallel to the beam-splitting surface of the beam-splitting prism; the optical path lengths of the transmitted and reflected rays of the eyepiece beam splitter are equal.

[0012] Preferably, the eyepiece is set vertically; the target surface of the CCD camera is set horizontally; the CCD camera is equipped with an imaging lens; and the height of the CCD camera is adjustable.

[0013] Preferably, the interference mirror group includes a collimating objective and a wedge mirror from top to bottom, with the optical mirror to be tested placed below the wedge mirror; the lower surface of the wedge mirror is a parallel plane and the upper surface is an inclined plane; the light beam passes through the beam splitter and is collimated by the collimating objective and then becomes parallel light and is emitted, and the diameter of the light beam is the maximum effective aperture that can be detected; the parallel light passes through the wedge mirror and is split into two beams for reflection.

[0014] Preferably, both the beam-splitting surface of the beam-splitting prism and the beam-splitting surface of the eyepiece beam-splitting lens are coated with a beam-splitting film and an anti-reflection film; the laser 1 is a circular spot helium-neon laser or a semiconductor laser.

[0015] Preferably, it includes the following steps:

[0016] S1: Place the optical mirror to be tested within the receiving area of ​​the testing stage;

[0017] S2: Turn on the laser;

[0018] S3: The laser emitted by the laser is expanded by a condenser lens group;

[0019] S4: The beam expanded passes through the beam splitter from the incident surface of the beam splitter and is collimated by the collimating objective lens;

[0020] S5: The collimated beam becomes parallel light and is emitted. After passing through the lower surface of the wedge mirror, the parallel light splits into two beams. Beam 1 is reflected back directly, and beam 2 is transmitted to the upper surface of the optical mirror to be tested and reflected back. There is a stable phase difference between the reflected light of beam 1 and the reflected light of beam 2 and interference occurs.

[0021] S6: The reflected light from beam one and the reflected light from beam two both pass through the beam splitter from the exit surface of the beam splitter and then through the eyepiece beam splitter.

[0022] S7: Two beams of light are formed at the eyepiece beam splitter, namely beam three and beam four; beam three becomes parallel light after being transmitted through the eyepiece beam splitter and the eyepiece and enters the human eye to form an image; beam four enters the target surface of the CCD camera after being reflected by the eyepiece beam splitter and forms an interference fringe image.

[0023] Preferably, in step S7, when the target to be detected received by the human eye or CCD camera is unclear or located outside the field of view, the angle and height of the optical mirror to be tested in the accommodating area are adjusted, and steps S3-S7 are repeated until the parallel light entering the human eye through the eyepiece can be clearly imaged; then the interference fringe information is obtained by the CCD camera to determine the flatness of the optical mirror to be tested.

[0024] The beneficial effects of this invention are:

[0025] 1. This invention combines human visual observation with CCD display. The detection position can be initially adjusted by human observation, and the detection target can be finely adjusted by the CCD camera to obtain accurate interference fringe information. Compared with the glass sample method, it can avoid wear on the standard surface of the optical plane mirror under test. Compared with non-contact detection methods, it can greatly improve the accuracy of detection results. Compared with the use of digital interferometers, it can reduce detection costs and improve the versatility and applicability of detection.

[0026] 2. In this invention, the central axis of the condenser lens assembly is perpendicular to the optical axis of the laser; the horizontal center line connecting the eyepiece beam splitter and the eyepiece is collinear with the horizontal center line of the beam splitter prism; the collimating objective lens and the prism are coaxial; the angle between the beam splitting surface of the beam splitter prism and the horizontal plane is 45°; the beam splitting surface of the eyepiece beam splitter is parallel to the beam splitting surface of the beam splitter prism; the above settings can improve the accuracy of detection. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of the detection interference device provided according to an embodiment of the present invention.

[0028] Figure reference numerals: 1. Laser; 2. Condenser lens group; 3. Beam splitter; 4. Collimating objective lens; 5. Wedge lens; 6. Optical lens to be tested; 7. Eyepiece beam splitter; 8. Eyepiece; 9. Human eye; 10. CCD camera; 11. Beam splitting surface of beam splitter; 12. Beam splitting surface of eyepiece beam splitter; 13. Upper triangular pyramid; 14. Lower triangular pyramid. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the following description is provided in conjunction with the appendix. Figure 1 The present invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and do not constitute a limitation thereof.

[0030] A detection interferometer that combines visual observation and CCD display includes a detection stage with a receiving area for an optical mirror 6 to be tested. During detection, the optical mirror 6 is placed within the receiving area of ​​the detection stage; in this embodiment, the optical mirror 6 to be tested is a plane mirror. Figure 1 As shown, the testing stage is equipped with a laser 1 and a condenser lens group 2 located above the laser 1. The laser 11 is a circular spot helium-neon laser or a semiconductor laser. The condenser lens group 2 includes multiple condenser lenses, and the central axis of the condenser lens group 2 is parallel to... Figure 1 The horizontal plane shown at point S is parallel, and the optical axis of laser 1 is set perpendicular to the central axis of condenser lens group 2.

[0031] like Figure 1 As shown, a beam splitter 3 is provided on the side of the laser 1, located below the condenser lens group 2. The beam splitter 3 is formed by bonding together an upper triangular pyramid 13 and a lower triangular pyramid 14 arranged symmetrically. The bonding surface of the upper triangular pyramid 13 and the lower triangular pyramid 14 is the beam splitting surface 11 of the beam splitter prism. A beam splitting film and an anti-reflection film are coated on the beam splitting surface 11. The cone surface of the upper triangular pyramid 13 is the incident surface of the beam splitter prism 3, and the cone surface of the lower triangular pyramid 14 is the exit surface of the beam splitter prism 3. The angle between the beam splitting surface 11 of the beam splitter prism and the horizontal plane S is 45°.

[0032] Below the beam splitter prism 3 is a coaxial interferometer group. The optical mirror 6 to be tested is placed in the accommodating area of ​​the testing stage and is located below the interferometer group. The interferometer group includes a collimating objective lens 4 and a wedge lens 5 from top to bottom. The optical mirror 6 to be tested is placed below the wedge lens 5. The lower surface of the wedge lens 5 is a parallel plane, and the upper surface of the wedge lens 5 is an inclined plane. The light beam passes through the beam splitter prism 3 and is collimated by the collimating objective lens 4, becoming parallel light and exiting. The diameter of the light beam is the maximum effective aperture that can be detected. The parallel light passes through the wedge lens 5 and is split into two beams for reflection. The two beams are beam one and beam two. Beam one is reflected back directly, and beam two is transmitted to the upper surface of the optical mirror 6 to be tested and reflected back. The reflected light of beam one and the reflected light of beam two have the same frequency, and there is a stable phase difference between the reflected light of beam one and the reflected light of beam two, which interferes.

[0033] A visual observation lens group and a CCD camera 10 are provided on the side of the beam splitter prism 3 away from the laser 1. The CCD camera 10 is located above the visual observation lens group. The horizontal center line L of the visual observation lens group is collinear with the horizontal center line of the beam splitter prism 3. Specifically, the visual observation lens group includes an eyepiece beam splitter 7 and an eyepiece 8 arranged sequentially on the side of the beam splitter prism 3. The eyepiece 8 is arranged vertically and perpendicular to the horizontal plane S. The beam splitting surface 12 of the eyepiece beam splitter is coated with a beam splitting film and an anti-reflection film. The human eye 9 observes through the eyepiece 8. The horizontal center line L of the eyepiece beam splitter 7 and the eyepiece 8 is collinear with the horizontal center line of the beam splitter prism 3 and is parallel to the horizontal plane S. The beam splitting surface of the eyepiece beam splitter 12 is arranged parallel to the beam splitting surface 11 of the beam splitter prism. The optical path lengths of the transmitted and reflected rays of the eyepiece beam splitter 7 are equal.

[0034] like Figure 1 As shown, the CCD camera 10 is located above the eyepiece beam splitter 7. The target surface of the CCD camera 10 is set along the horizontal plane. The CCD camera 10 is equipped with an imaging lens and the height of the CCD camera 10 is adjustable.

[0035] The orientation of the interference detection device can be adjusted using a three-top-three-pull structure or a two-top-two-pull structure, and its height can be adjusted using a Z-axis displacement stage.

[0036] A detection method that combines visual observation and CCD display, using the aforementioned detection device to detect the flatness of the optical mirror 6 to be tested, i.e., to detect the surface shape error of the optical mirror 6 to be tested, includes the following steps:

[0037] S1: Place the optical mirror 6 to be tested within the receiving area of ​​the testing stage;

[0038] S2: Turn on laser 1;

[0039] S3: The laser emitted by laser 1 is expanded by the focusing lens group 2;

[0040] S4: The beam expanded passes through the beam splitter 3 from the incident surface of the beam splitter 3 and is collimated by the collimating objective lens 4;

[0041] S5: The collimated beam becomes parallel light and is emitted. After passing through the lower surface of the wedge mirror 5, the parallel light splits into two beams. Beam 1 is reflected back directly, and beam 2 is transmitted to the upper surface of the optical mirror 6 to be tested and reflected back. There is a stable phase difference between the reflected light of beam 1 and the reflected light of beam 2 and interference occurs.

[0042] S6: The reflected light from beam one and the reflected light from beam two both pass through beam splitter 3 from the exit surface of beam splitter 3 and then through eyepiece beam splitter 7.

[0043] S7: Two beams of light are formed at the eyepiece beam splitter 7, namely beam three and beam four; beam three becomes parallel light after being transmitted through the eyepiece beam splitter 7 and eyepiece 8 and enters the human eye 9 to form an image; beam four enters the target surface of the CCD camera 10 after being reflected by the eyepiece beam splitter 7 and forms an interference fringe image; when the image of the target to be detected received by the human eye 9 or the CCD camera 10 is not clear or is located outside the field of view, the angle and height of the optical mirror 6 to be tested in the accommodating area are adjusted, and the operation steps S3-S7 are repeated until the parallel light entering the human eye 9 through the eyepiece 8 can form a clear image; then the interference fringe information is obtained by the CCD camera 10 to determine the flatness of the optical mirror 6 to be tested.

[0044] It is worth noting that when it is necessary to test the parallelism of optical components, the wedge mirror 5 can be removed, the plane mirror 6 to be tested can be moved up to the position of the wedge mirror 5, and the above steps can be repeated to complete the test of the parallelism of the optical components.

[0045] Although embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

[0046] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A detection interferometer that combines visual observation and CCD display, comprising a detection stage, characterized in that, The testing stage is equipped with a laser (1) and a condenser lens group (2) located above the laser (1), with the central axis of the condenser lens group (2) perpendicular to the optical axis of the laser (1). A beam splitter (3) is located on the side of the laser (1) and below the condenser lens group (2). A coaxial interferometer group is located below the beam splitter (3), and the optical lens (6) to be tested is placed in the receiving area of ​​the testing stage and located below the interferometer group. The interferometer group includes a collimating objective lens (4) and a wedge lens (5) from top to bottom, and the optical lens (6) to be tested is placed below the wedge lens (5). The lower surface of the wedge mirror (5) is a parallel surface, and the upper surface of the wedge mirror (5) is an inclined surface. The beam passes through the beam splitter (3) and is collimated by the collimating objective (4) and then becomes parallel light. The diameter of the beam is the maximum effective aperture that can be detected. The parallel light passes through the wedge mirror (5) and is split into two beams for reflection. The beam splitter (3) is provided with a visual observation mirror group and a CCD camera (10) on the side away from the laser (1). The horizontal center line of the visual observation mirror group is collinear with the horizontal center line of the beam splitter (3). The CCD camera (10) is located above the visual observation mirror group. The visual observation lens group includes an eyepiece beam splitter (7) and an eyepiece (8) arranged sequentially on the side of the beam splitter (3). The human eye (9) observes through the eyepiece (8). The horizontal center line connecting the eyepiece beam splitter (7) and the eyepiece (8) is collinear with the horizontal center line of the beam splitter (3). The CCD camera (10) is located above the eyepiece beam splitter (7). When the image of the target to be detected received by the human eye (9) or the CCD camera (10) is unclear or located outside the field of view, the angle and height of the optical mirror (6) to be detected in the accommodating area are adjusted until the parallel light entering the human eye (9) through the eyepiece (8) can be clearly imaged.

2. The detection interferometer device for both visual observation and CCD display according to claim 1, characterized in that, The beam splitter (3) is formed by gluing together an upper triangular pyramid (13) and a lower triangular pyramid (14) arranged symmetrically. The gluing surface of the upper triangular pyramid (13) and the lower triangular pyramid (14) is the beam splitting surface (11) of the beam splitter. The cone surface of the upper triangular pyramid (13) is the incident surface of the beam splitter (3), and the cone surface of the lower triangular pyramid (14) is the exit surface of the beam splitter (3).

3. The detection interferometer device for both visual observation and CCD display according to claim 2, characterized in that, The angle between the beam-splitting surface (11) of the beam-splitting prism and the horizontal plane is 45°.

4. The detection interferometer device for both visual observation and CCD display according to claim 3, characterized in that, The beam-splitting surface (12) of the eyepiece beam splitter is set parallel to the beam-splitting surface (11) of the beam splitter prism; the optical path of the transmitted light and the reflected light of the eyepiece beam splitter (7) are equal.

5. The detection interferometer device for both visual observation and CCD display according to claim 4, characterized in that, The eyepiece (8) is set in the vertical direction; the target surface of the CCD camera (10) is set in the horizontal direction, the CCD camera (10) is equipped with an imaging lens, and the height of the CCD camera (10) is adjustable.

6. The detection interferometer device for both visual observation and CCD display according to claim 1, characterized in that, The beam-splitting surface (11) of the beam-splitting prism and the beam-splitting surface (12) of the eyepiece beam-splitting lens are both coated with a beam-splitting film and an anti-reflection film; the laser (1) is a circular spot helium-neon laser or a semiconductor laser.

7. A detection method that combines visual observation and CCD display, comprising using the detection device according to any one of claims 1-6 to detect the flatness of the optical mirror (6) to be tested, characterized in that, Includes the following steps: S1: Place the optical mirror (6) to be tested in the receiving area of ​​the testing stage; S2: Turn on the laser (1); S3: The laser emitted by the laser (1) is expanded by the condenser lens group (2); S4: The beam expanded passes through the beam splitter (3) from the incident surface of the beam splitter (3) and is collimated by the collimating objective lens (4); S5: The collimated beam becomes parallel light and is emitted. After passing through the lower surface of the wedge mirror (5), the parallel light is split into two beams. Beam 1 is reflected back directly, and beam 2 is transmitted to the upper surface of the optical mirror (6) to be tested and reflected back. There is a stable phase difference between the reflected light of beam 1 and the reflected light of beam 2 and interference occurs. S6: The reflected light from beam one and the reflected light from beam two both pass through the beam splitter (3) from the exit surface of the beam splitter (3) and then through the eyepiece beam splitter (7). S7: Two beams of light are formed at the eyepiece beam splitter (7), namely beam three and beam four. After beam three is transmitted through the eyepiece beam splitter (7) and the eyepiece (8), it becomes parallel light and enters the human eye (9) to form an image. After beam four is reflected by the eyepiece beam splitter (7), it enters the target surface of the CCD camera (10) and forms an interference fringe image. When the target received by the human eye (9) or the CCD camera (10) is not clear or is located outside the field of view, the angle and height of the optical mirror (6) to be tested in the accommodating area are adjusted, and the operation steps S3-S7 are repeated until the parallel light entering the human eye (9) through the eyepiece (8) can form a clear image. Then, the interference fringe information is obtained through the CCD camera (10) to determine the flatness of the optical mirror (6) to be tested.

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