A dual-optical path lens distance measurement system and working method thereof

Abstract

The present invention relates to a dual-light path lens spacing measurement system and a working method thereof, comprising a broadband light source, an optical lens, a first beam splitter, a second beam splitter, a first reflector, a second reflector, a double-sided reflector, an electric guide rail and a detector, wherein the electric guide rail is arranged between the first reflector and the second reflector, and the double-sided reflector is mounted on the electric guide rail; the first beam splitter reflects the light beam emitted by the broadband light source to the optical lens, and the light beam reflected by each reflective surface of the lens forms two light paths through the beam splitter, and the two light paths are reflected by the double-sided reflector; when the detector detects the interference signal of the two light paths and there is an optical path difference between the two light paths, the electric guide rail drives the double-sided reflector to move a distance that is one-fourth of the spacing between the other reflective surfaces and the first reflective surface, and by measuring the moving distance of the double-sided reflector on the electric guide rail, the spacing between the other reflective surfaces and the first reflective surface can be calculated. The present invention is reasonably designed and can improve the speed of measuring large-pitch lenses.

Description

Technical field:

[0002] The invention belongs to the technical field of optical lens spacing detection, and in particular relates to a dual-light path lens spacing measurement system and a working method thereof. Background technology:

[0004] Lens spacing includes lens thickness and air gap thickness between lenses, which are important parameters of lenses and must be measured before leaving the factory. Currently, lens spacing is mostly measured by optical coherence tomography based on the Michelson interference principle. When the reference arm uses a fast scanning delay line to change the scanning optical path, it can only be used for small-sized lenses such as mobile phone lenses because its scanning range is 1-3mm. The advantage is fast measurement speed and the disadvantage is small measurement range. When the lens spacing is large, the optical path matching is mostly performed by the method of electric guide rail translation mirror. The advantage is that lenses with large spacing can be measured, but the measurement speed is slow when measuring lenses with large spacing due to the low reciprocating motion frequency of the electric guide rail. Summary of the invention:

[0006] The present invention makes improvements on the problems existing in the above-mentioned prior art, that is, the technical problem to be solved by the present invention is to provide a dual-light path lens spacing measurement system and a working method thereof, which are reasonably designed and effectively improve the speed of measuring large-pitch lenses.

[0007] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a dual-light path lens spacing measurement system, including a broadband light source, an optical lens, a first beam splitter, a second beam splitter, a first reflector, a second reflector, a double-sided reflector, an electric guide rail and a detector, the optical lens, the first beam splitter, the second beam splitter and the first reflector are arranged side by side, the second reflector and the detector are respectively arranged on two opposite sides of the second beam splitter, the electric guide rail is tiltedly arranged between the first reflector and the second reflector, and the double-sided reflector is installed on the electric guide rail; the first beam splitter reflects the light beam emitted by the broadband light source to the optical lens, and the light beam reflected by each reflection surface of the optical lens passes through the first beam splitter and the second beam splitter in sequence to form a first light path and a second light path, the first light path passes through the first reflector and the double-sided reflector and then reflects into the detector, the second light path passes through the second reflector and the double-sided reflector and then reflects into the detector, and the detector is used to detect an interference signal when interference occurs between the first light path and the second light path.

[0008] Furthermore, the reflective surfaces of the optical lens include a first reflective surface and several other reflective surfaces. The first reflective surface is located at one end of the optical lens close to the first beam splitter. When the detector detects an interference signal between the first optical path and the second optical path and there is an optical path difference between the first optical path and the second optical path, the moving distance of the electric guide rail is one quarter of the distance between the other reflective surfaces and the first reflective surface.

[0009] Further, when the moving distance of the electric guide rail is one quarter of the distance between the other reflective surfaces and the first reflective surface, the optical path difference between the first optical path and the second optical path is the distance between the other reflective surfaces and the first reflective surface.

[0010] Furthermore, the reflection path of the first light path and the reflection path of the second light path are distributed in a right triangle.

[0011] Furthermore, the double-sided reflector is a TIR reflector or a plane reflector.

[0012] Furthermore, the broadband light source and the detector are located on the same side of the light beam after being reflected by each reflection surface of the optical lens.

[0013] Another technical solution adopted by the present invention is: a working method of a dual-light path lens spacing measurement system, when working: a broadband light source emits a laser with a short coherent wavelength, which is projected through a first beam splitter and reflected to an optical lens, and then reflected by each reflection surface of the optical lens and then passed through the first beam splitter again, and then incident on a second beam splitter, and is divided into a first light path and a second light path, the first light path passes through a first reflector and a double-sided reflector and then reflects into a detector, and the second light path passes through a second reflector and a double-sided reflector and then reflects into a detector;

[0014] (1) In the initial state, the optical path of the first optical path is the same as that of the second optical path. The light beams returned from each reflective surface of the optical lens interfere with each other, and the interference signal is detected by the detector. At this time, the position of the double-sided reflector on the electric guide rail is recorded as the zero point, representing the position of the first reflective surface of the optical lens.

[0015] (2) The electric guide rail drives the double-sided reflector to move toward the first reflector or the second reflector. When the first light path interferes with the second light path and the interference signal is detected by the detector, the moving distance of the double-sided reflector on the electric guide rail relative to the zero point is measured. At this time, the moving distance of the double-sided reflector driven by the electric guide rail is one-fourth of the distance between the other reflective surface and the first reflective surface. The distance between the other reflective surface and the first reflective surface is then calculated.

[0016] (3) The electric guide rail drives the double-sided reflector to continue to move along the moving direction in step (2). When the first light path and the second light path interfere with each other again and the interference signal is detected by the detector, the moving distance of the double-sided reflector on the electric guide rail relative to the zero point is measured again. At this time, the moving distance of the double-sided reflector driven by the electric guide rail is one-fourth of the distance between the next other reflective surface and the first reflective surface. The distance between the other reflective surface and the first reflective surface is obtained by calculation.

[0017] (4) Repeat steps (2) to (3) until the distances between the remaining reflective surfaces in the optical lens and the first reflective surface are measured.

[0018] Compared with the prior art, the present invention has the following effects: the present invention is reasonably designed, and the electric guide rail drives the double-sided reflector to move in two directions to measure the distance between the other reflective surfaces of the optical lens and the first reflective surface of the optical lens, and then obtains the distance of the air gap between the lenses of the optical lens, which can improve the speed of measuring large-pitch lenses. Description of the drawings:

[0020] Figure 1 is a light path diagram in which the first light path and the second light path have the same optical path length in an embodiment of the present invention;

[0021] Figure 2 is a light path diagram when the electric guide rail moves toward the first reflector in an embodiment of the present invention;

[0022] Figure 3 1 is a light path diagram when the electric guide rail moves toward the second reflector in an embodiment of the present invention.

[0023] In the figure:

[0024] 1- broadband light source; 2- first beam splitter; 3- detector; 4- second beam splitter; 5- first reflecting surface; 6- second reflecting surface; 7- third reflecting surface; 8- fourth reflecting surface; 9- second reflecting mirror; 10- electric guide rail; 11- double-sided reflecting mirror; 12- first reflecting mirror; 13- first optical path; 14- second optical path; 15- light beam reflected by the reflecting surface; 16- optical lens; 17- zero point. Specific implementation method:

[0026] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0027] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicating orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0028] like Figures 1 to 3As shown, a dual-light path lens spacing measurement system of the present invention includes a broadband light source 1 for emitting a laser with a short coherent wavelength, an optical lens 16, a first beam splitter 2, a second beam splitter 4, a first reflector 12, a second reflector 9, a double-sided reflector 11, an electric guide rail 10 and a detector 3. The optical lens 16, the first beam splitter 2, the second beam splitter 4 and the first reflector 12 are arranged side by side from right to left, the second reflector 9 and the detector 3 are respectively arranged on two opposite sides of the second beam splitter 4, the electric guide rail 10 is tilted between the first reflector 12 and the second reflector 9, the double-sided reflector 11 is installed on the electric guide rail 10, and the electric guide rail 10 drives the double-sided reflector 11 to move between the first reflector 12 and the second reflector 9; each reflection surface of the optical lens 16 includes a first reflection surface 5 and a plurality of other reflection surfaces, and the first reflection surface 5 is located at one end of the optical lens 16 close to the first beam splitter 2.

[0029] The first beam splitter 2 reflects the short coherent wavelength laser emitted by the broadband light source 1 to the optical lens 16. The light beam 15 reflected by each reflective surface of the optical lens 16 passes through the first beam splitter 2 and the second beam splitter 4 in sequence to form a first light path 13 and a second light path 14. The first light path 13 is reflected by the first reflector 12 and then incident on the double-sided reflector 11, and then reflected by the double-sided reflector 11 and returned. The second light path 14 is reflected by the second reflector 9 and then incident on the double-sided reflector 11, and then reflected by the double-sided reflector 11 and returned. The detector 3 is used to detect the interference signal when the first optical path 13 and the second optical path 14 interfere with each other. When the detector 3 detects the interference signal between the first optical path 13 and the second optical path 14 and there is an optical path difference between the first optical path 13 and the second optical path 14, the moving distance of the double-sided reflector 11 driven by the electric guide rail 10 is one quarter of the distance between the other reflective surface of the optical lens 16 and the first reflective surface 5, that is, by measuring the moving distance of the double-sided reflector driven by the electric guide rail 10, the distance between the other reflective surface in the optical lens and the first reflective surface can be calculated.

[0030] In this embodiment, when the moving distance of the electric guide rail 10 is one quarter of the distance between the other reflecting surface and the first reflecting surface 5, the optical path difference between the first optical path 13 and the second optical path 14 is the distance between the other reflecting surface and the first reflecting surface 5, and the optical path change of the first optical path 13 is the same as the optical path change of the second optical path 14, both of which are half of the distance between the other reflecting surface and the first reflecting surface 5. For example, when the electric guide 10 drives the double-sided reflector 11 to move toward the first reflector 12, the optical path of the second optical path 14 increases, while the optical path of the first optical path 13 decreases. At this time, the optical path of the light reflected by the first reflective surface 5 through the second optical path 14 is the same as the optical path of the light reflected by other reflective surfaces through the first optical path 13, and interference occurs to generate an interference signal; similarly, when the electric guide 10 drives the double-sided reflector 11 to move toward the second reflector 9, the optical path of the second optical path 14 decreases, while the optical path of the first optical path 13 increases. At this time, the optical path of the light reflected by the first reflective surface 5 through the first optical path 13 is the same as the optical path of the light reflected by other reflective surfaces through the second optical path 14, and interference occurs to generate an interference signal. That is, the electric guide 10 drives the double-sided reflector 11 to move in both directions to measure the distance between the other reflective surfaces in the optical lens 16 and the first reflective surface of the optical lens, and then obtains the distance of the air interval between the lenses of the optical lens, which can realize that the measurement speed of the interval between the reflective surfaces of the lens is increased to twice the original speed, greatly improving the measurement speed.

[0031] In this embodiment, the reflection path of the first optical path 13 and the reflection path of the second optical path 14 are distributed in a right triangle, and the path of the first optical path 13 between the first reflector 12 and the double-sided reflector 11, the path of the second optical path 14 between the second reflector 9 and the double-sided reflector 11, and the electric guide rail 10 are parallel.

[0032] In this embodiment, the double-sided reflector 11 may be a TIR reflector or a plane reflector.

[0033] In this embodiment, the broadband light source 1 and the detector 3 are located on the same side of the light beam 15 after being reflected by the reflection surfaces of the optical lens 16 .

[0034] In this embodiment, it should be noted that each reflective surface in the optical lens is a lens.

[0035] In this embodiment, the working process of the measurement system is as follows: a broadband light source 1 emits a laser with a short coherent wavelength, the laser projection is reflected by the first beam splitter 2 to the optical lens 16, after being reflected by each reflection surface of the optical lens 16, it passes through the first beam splitter 2 again, and is incident on the second beam splitter 4, the second beam splitter 4 divides the light beam into a first light path 13 and a second light path 14, the first light path 13 is reflected by the first reflector 12 to the double-sided reflector 11, the first light path 13 after being reflected by the double-sided reflector 11 passes through the first reflector 12 and the second beam splitter 4 in sequence, and then is reflected into the detector 3, the second light path 14 is reflected by the second reflector 9 to the double-sided reflector 11, the second light path 14 after being reflected by the double-sided reflector 11 passes through the second reflector 9 and the second beam splitter 4 in sequence, and then is reflected into the detector 3;

[0036] (1) In the initial state, the optical path of the first optical path 13 is the same as that of the second optical path 14. The light beams returned from the various reflection surfaces of the optical lens 16 interfere with each other, and the interference signal is detected by the detector 3. At this time, the position of the double-sided reflector 11 on the electric guide rail 10 is recorded as the zero point 17, which represents the position of the first reflection surface 5 of the optical lens 16. Figure 1 As shown;

[0037] (2) The electric guide rail 10 drives the double-sided reflector 11 to move toward the first reflector 12 or the second reflector 9. When the first optical path 13 and the second optical path 14 interfere with each other and the interference signal is detected by the detector 3, the moving distance of the double-sided reflector 11 on the electric guide rail 10 relative to the zero point 17 is measured. At this time, the moving distance of the double-sided reflector 11 driven by the electric guide rail 10 is one-fourth of the distance between the other reflective surface and the first reflective surface 5. Then, the distance between the other reflective surface and the first reflective surface is obtained by calculation.

[0038] (3) The electric guide rail 10 drives the double-sided reflector 11 to continue to move along the moving direction in step (2). When the first optical path 13 and the second optical path 14 interfere with each other again and the interference signal is detected by the detector 3, the moving distance of the double-sided reflector 11 on the electric guide rail 10 relative to the zero point 17 is measured again. At this time, the moving distance of the double-sided reflector 11 driven by the electric guide rail 10 is one quarter of the distance between the next other reflective surface and the first reflective surface. The distance between the other reflective surface and the first reflective surface is obtained by calculation.

[0039] (4) Repeat steps (2) to (3) until the distances between the remaining reflective surfaces in the optical lens and the first reflective surface are measured.

[0040] Specific implementation process: the optical lens 16 includes a first reflection surface 5, a second reflection surface 6, a third reflection surface 7 and a fourth reflection surface 8 which are arranged from right to left in sequence, the distance between the second reflection surface 6 and the first reflection surface 5 is d1, the distance between the third reflection surface 7 and the second reflection surface 6 is d2, and the distance between the fourth reflection surface 8 and the third reflection surface 7 is d3;

[0041] like Figure 1 As shown, Figure 1 The optical path of the first optical path is the same as that of the second optical path. The broadband light source 1 emits a laser with a short coherent wavelength, which is projected through the first beam splitter 2 and reflected to the optical lens 16. After being reflected by each reflection surface of the optical lens 16, it passes through the first beam splitter 2 again, enters the second beam splitter 4, and is divided into the first optical path 13 and the second optical path 14. After being reflected by the double-sided reflector 11, it enters the detector 3. In the initial state, the optical path of the second optical path 14 is the same as that of the first optical path 13, so the optical paths of the light beam 15 reflected back by each reflection surface of the optical lens 16 through the second beam splitter 4 are the same, and interference occurs. The interference signal is detected by the detector 3. At this time, the position of the double-sided reflector 11 on the electric guide rail 10 is recorded as the zero point, representing the position of the first reflection surface 5 of the sample;

[0042] like Figure 2 As shown, Figure 2 The optical path difference between the first optical path and the second optical path is d1, and the distance between the first reflective surface 5 and the second reflective surface 6 of the lens can be measured at this time: when the electric guide rail 10 drives the double-sided reflector 11 to move toward the first reflector 12 (forward) by a distance of d1 / 4, the optical path of the first optical path 13 is reduced by d1 / 2, and the optical path of the second optical path 14 is increased by d1 / 2; since the distance between the first reflective surface 5 and the second reflective surface 6 of the optical lens 16 is d1, the light returned from the first reflective surface 6 of the optical lens 16 passes through the second optical path 14, and the optical path difference is the same as the light returned from the second reflective surface 6 of the optical lens 16 passing through the first optical path 13, and interference occurs, and the interference signal is detected by the detector 3. By recording the moving distance of the double-sided reflector 11 driven by the electric guide rail 10, the distance d1 between the second reflective surface 6 of the optical lens and the first reflective surface 5 of the optical lens can be calculated;

[0043] like Figure 3 As shown, Figure 2The optical path difference between the first optical path 13 and the second optical path 14 is d4. At this time, the distance between the first reflection surface 5 and the third reflection surface 7 of the optical lens 16 can be measured: when the electric guide rail 10 drives the double-sided reflection mirror 11 to move a distance d4 / 4 toward the second reflection mirror 9 (in the reverse direction), the optical path of the second optical path 14 is reduced by d4 / 2, and the optical path of the first optical path 13 is increased by d4 / 2; since the distance between the first reflection surface 5 and the third reflection surface 7 of the optical lens 16 is d4, the light returned from the first reflection surface 5 of the optical lens 16 passes through the first optical path 13, and the optical path difference with the light returned from the third reflection surface 7 of the optical lens passes through the second optical path 14 is the same, and interference occurs. The interference signal is detected by the detector 3. By recording the moving distance of the double-sided reflection mirror 11 driven by the electric guide rail 10, the distance d4 between the third reflection surface 7 and the first reflection surface 5 of the sample can be calculated;

[0044] That is, no matter which direction the electric guide rail 10 drives the double-sided reflector 11 to move, the distances between each reflective surface of the optical lens 16 and the first reflective surface 5 can be measured respectively, and then the distances between each lens and each air gap can be calculated.

[0045] If the present invention discloses or involves components or structures that are fixedly connected to each other, then, unless otherwise stated, the fixed connection can be understood as: a detachable fixed connection (for example, connection using bolts or screws), and can also be understood as: a non-detachable fixed connection (for example, riveting, welding). Of course, the mutual fixed connection can also be replaced by an integrated structure (for example, manufactured by integrated molding using a casting process) (except when it is obviously impossible to use an integrated molding process).

[0046] In addition, unless otherwise stated, the terms used to indicate positional relationships or shapes in any of the technical solutions disclosed in the present invention include states or shapes that are approximate, similar, or close to them.

[0047] Any component provided by the present invention may be assembled from a plurality of separate components, or may be a separate component manufactured by an integral forming process.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or some technical features can be replaced by equivalents without departing from the spirit of the technical solution of the present invention, which should be included in the scope of the technical solution for protection of the present invention.

Claims

1. A dual-light path lens spacing measurement system, characterized in that: It comprises a broadband light source, an optical lens, a first beam splitter, a second beam splitter, a first reflector, a second reflector, a double-sided reflector, an electric guide rail and a detector, wherein the optical lens, the first beam splitter, the second beam splitter and the first reflector are arranged side by side, the second reflector and the detector are respectively arranged on two opposite sides of the second beam splitter, the electric guide rail is tiltedly arranged between the first reflector and the second reflector, and the double-sided reflector is installed on the electric guide rail; the first beam splitter reflects the light beam emitted by the broadband light source to the optical lens, and the light beam reflected by each reflective surface of the optical lens passes through the first beam splitter and the second beam splitter in sequence to form a first light path and a second light path, the first light path passes through the first reflector and the double-sided reflector and then reflects into the detector, the second light path passes through the second reflector and the double-sided reflector and then reflects into the detector, and the detector is used to detect an interference signal when interference occurs between the first light path and the second light path; Each reflective surface of the optical lens includes a first reflective surface and a plurality of other reflective surfaces, the first reflective surface is located at one end of the optical lens close to the first beam splitter, when the detector detects an interference signal between the first optical path and the second optical path and there is an optical path difference between the first optical path and the second optical path, the moving distance of the electric guide rail is one quarter of the distance between the other reflective surfaces and the first reflective surface; The reflection path of the first light path and the reflection path of the second light path are distributed in a right triangle.

2. A dual-light path lens distance measurement system according to claim 1, characterized in that: When the moving distance of the electric guide rail is one quarter of the distance between the other reflective surfaces and the first reflective surface, the optical path difference between the first optical path and the second optical path is the distance between the other reflective surfaces and the first reflective surface.

3. The dual-light path lens distance measurement system according to claim 1, characterized in that: The double-sided reflector is a TIR reflector or a plane reflector.

4. The dual-light path lens distance measurement system according to claim 1, characterized in that: The broadband light source and the detector are located on the same side of the light beam reflected by each reflection surface of the optical lens.

5. A working method of a dual-light path lens spacing measurement system, characterized in that: The system comprises a dual-light path lens spacing measurement system as claimed in claim 2, wherein when in operation: a broadband light source emits a laser with a short coherent wavelength, which is projected through a first beam splitter and reflected to an optical lens, and then reflected by each reflective surface of the optical lens and then passed through the first beam splitter again, and then incident on a second beam splitter to be divided into a first light path and a second light path, and the first light path is reflected into a detector after passing through a first reflector and a double-sided reflector, and the second light path is reflected into a detector after passing through a second reflector and a double-sided reflector; (1) In the initial state, the optical path of the first optical path is the same as that of the second optical path. The light beams returned from each reflective surface of the optical lens interfere with each other, and the interference signal is detected by the detector. At this time, the position of the double-sided reflector on the electric guide rail is recorded as the zero point, representing the position of the first reflective surface of the optical lens. (2) The electric guide rail drives the double-sided reflector to move toward the first reflector or the second reflector. When the first light path interferes with the second light path and the interference signal is detected by the detector, the moving distance of the double-sided reflector on the electric guide rail relative to the zero point is measured. At this time, the moving distance of the double-sided reflector driven by the electric guide rail is one-fourth of the distance between the other reflective surface and the first reflective surface. The distance between the other reflective surface and the first reflective surface is then calculated. (3) The electric guide rail drives the double-sided reflector to continue to move along the moving direction in step (2). When the first light path and the second light path interfere with each other again and the interference signal is detected by the detector, the moving distance of the double-sided reflector on the electric guide rail relative to the zero point is measured again. At this time, the moving distance of the double-sided reflector driven by the electric guide rail is one-fourth of the distance between the next other reflective surface and the first reflective surface. The distance between the other reflective surface and the first reflective surface is obtained by calculation. (4) Repeat steps (2) to (3) until the distances between the remaining reflective surfaces in the optical lens and the first reflective surface are measured.

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