A method for assembling and adjusting a transmission-type near-infrared beam expansion system

Abstract

The present invention discloses a transmission type near infrared beam expansion system adjustment method, the adjustment method comprises: S1: based on the use requirements, the optical design of the beam expansion system is completed at the use wavelength; S2: under the adjustment wavelength condition, a compensation plate is added between the eyepiece and the objective lens of the beam expansion system, and the thickness value of the compensation plate is obtained based on the system aberration condition preset in step S1; S3: an interferometer, an eyepiece, a compensation plate, an objective lens and a reflector are fixed on the adjustment device in sequence, and the parallel light emitted by the interferometer passes through the eyepiece, the compensation plate and the objective lens in sequence, and is reflected by the reflector and returned along the original optical path to obtain interference fringes and their aberrations, and the eyepiece and / or objective lens profile are repeatedly corrected based on the aberrations until the interference aberrations meet the use requirements in step S1. The adjustment method of the present invention solves the processing adjustment problem caused by the inconsistency between the use wavelength and the adjustment wavelength of the near infrared beam expansion system by designing and adding the compensation plate 3.

Description

Technical Field

[0001] The invention belongs to the field of beam expansion system assembly and adjustment, and in particular relates to a transmission type near-infrared beam expansion system assembly and adjustment method. Background Art

[0002] Transmissive beam expansion systems are widely used in various optical systems. The operating wavelength of some optical systems is in the near-infrared (such as λ=1064nm), but the processing and adjustment of general beam expansion systems are carried out under a visible light interferometer (such as λ=632.8nm or λ=658nm, etc.), resulting in inconsistencies between the design and operating wavelength of the beam expansion system and the wavelength of processing and adjustment.

[0003] There are currently two solutions:

[0004] One is to design the achromatic aberration by taking into account both the wavelength used and the wavelength adjusted. This solution will make the beam expansion system more complicated, increase the number of optical components, reduce the transmittance, and increase the volume scale.

[0005] Another solution is to first perform processing and adjustment under the wavelength of visible light, and then confirm the aberration under the use wavelength collimator. This solution requires the mechanical parts of the beam expander system to take into account two states (processing and adjustment state and formal use state), which makes the structural parts of the beam expander system more complex and has higher requirements for processing accuracy. After completing the adjustment under the wavelength of visible light, it is necessary to switch to the formal use state, and it is also necessary to build an aberration confirmation optical path to confirm the aberration in the formal state and the use wavelength. Due to the insufficient processing positioning accuracy of the mechanical parts, fine-tuning is generally required again when switching to the formal state. This solution makes the mechanical parts more complex, requires higher machining accuracy, and the adjustment process is more complicated. Summary of the invention

[0006] The purpose of the present invention is to provide a transmission-type near-infrared beam expansion system assembly and adjustment method to overcome the defects of the prior art. The assembly and adjustment method of the present invention solves the processing and adjustment problem caused by the inconsistency between the wavelength used by the near-infrared beam expansion system and the adjustment wavelength by designing and adding a compensation plate.

[0007] The object of the present invention is achieved through the following technical solutions:

[0008] A transmission type near-infrared beam expansion system adjustment method, the adjustment method comprises: S1: based on the use requirements, completing the optical design of the beam expansion system at the use wavelength, the beam expansion system at least comprising an eyepiece and an objective lens; S2: under the adjustment wavelength condition, adding a compensation plate between the eyepiece and the objective lens of the beam expansion system, and obtaining the thickness value of the compensation plate based on the system aberration condition preset in step S1; S3: fixing an interferometer, an eyepiece, a compensation plate, an objective lens and a reflector in sequence on an adjustment device, parallel light emitted by the interferometer passes through the eyepiece, the compensation plate and the objective lens in sequence, and is reflected by the reflector and then returned along the original optical path, the returned test light interferes with the standard light of the interferometer, interference fringes and their system aberrations are obtained, and the eyepiece and / or objective lens are repeatedly corrected based on the system aberrations of the interference fringes until the system aberrations of the interference fringes meet the use requirements in step S1; S4: after the surface correction of the eyepiece and / or objective lens in the beam expansion system is completed, the compensation plate is removed from the adjustment device, and the adjustment of the beam expansion system is completed.

[0009] According to a preferred embodiment, the use requirements of step S1 include the design aberration of the beam expansion system.

[0010] According to a preferred embodiment, after the optical design of the beam expansion system in step S1 is completed, the thickness, curvature and spacing parameters of the eyepiece and objective lens are fixed.

[0011] According to a preferred embodiment, in step S2, the compensating plate is disposed close to the eyepiece.

[0012] According to a preferred embodiment, the interferometer is a visible light interferometer.

[0013] According to a preferred embodiment, the reflector is a plane reflector.

[0014] The aforementioned main scheme of the present invention and its further options can be freely combined to form multiple schemes, all of which are schemes that can be adopted and claimed for protection by the present invention; and in the present invention, (non-conflicting options) options and other options can also be freely combined. After understanding the scheme of the present invention, those skilled in the art can understand that there are many combinations based on the prior art and common knowledge, all of which are technical schemes to be protected by the present invention, and they are not exhaustively listed here.

[0015] Beneficial effects of the present invention: The present invention solves the processing and adjustment problem caused by the inconsistency between the wavelength used by the near-infrared beam expansion system and the adjustment wavelength by designing and adding a compensation plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the optical path involved in the adjustment method of the present invention;

[0017] Among them, 1-interferometer, 2-eyepiece, 3-compensation plate, 4-objective lens, 5-reflecting mirror. DETAILED DESCRIPTION

[0018] Terms such as "horizontal", "vertical", and "overhanging" do not mean that the components must be absolutely horizontal or overhanging, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0019] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0020] In addition, the present invention should be pointed out that, in the present invention, unless the specific structure, connection relationship, positional relationship, power source relationship, etc. are specifically written out, the structure, connection relationship, positional relationship, power source relationship, etc. involved in the present invention are all known by those skilled in the art on the basis of the prior art without creative work.

[0021] Embodiment 1:

[0022] refer to Figure 1 As shown, the present invention discloses a transmission type near infrared beam expansion system adjustment method, the adjustment method comprising:

[0023] Step S1: Based on usage requirements, complete the optical design of the beam expansion system at the wavelength of use, and the beam expansion system at least includes an eyepiece 2 and an objective lens 4.

[0024] Preferably, the use requirements of step S1 include the design aberration of the beam expansion system. For example, for certain working conditions, the design aberration of the beam expansion system may be 1 / 4 wavelength or 1 / 5 wavelength. The use wavelength may be λ=1064nm.

[0025] Preferably, after the optical design of the beam expansion system in step S1 is completed, the thickness, curvature and spacing parameters of the eyepiece 2 and the objective lens 4 are fixed.

[0026] Step S2: Under the wavelength adjustment condition, a compensating plate 3 is added between the eyepiece 2 and the objective lens 4 of the beam expansion system, and the thickness value of the compensating plate 3 is obtained based on the system aberration condition preset in step S1.

[0027] The wavelength adjustment in step S2 is the wavelength of light used in the process of installing and adjusting the beam expansion system, which is generally a visible light wavelength, for example, λ=632.8 nm.

[0028] Specifically, the compensation plate 3 is used to compensate for the optical path difference caused by the difference between the used wavelength and the adjusted wavelength of the beam expansion system, so that the optical path and system aberration of the beam expansion system are consistent in two states. The thickness value of the compensation plate can be calculated in the optical design software. First, the beam expansion system design is completed under the used wavelength, and the curvature radius and thickness parameters of the eyepiece and the objective lens, as well as the spacing between the eyepiece and the objective lens are solidified. Secondly, the system wavelength is modified to the adjusted wavelength, and a parallel plate is added between the eyepiece and the objective lens, and its thickness value is set as the only variable. Finally, iterative optimization is performed until the system aberration is consistent with the used wavelength, that is, the compensation plate design is completed.

[0029] Preferably, in step S2, the compensating plate 3 is arranged close to the eyepiece 2. Being arranged close to the eyepiece 2 helps to reduce the optical size of the plate, and reduce the material used and the space occupied by the compensating plate 3.

[0030] Step S3: The interferometer 1, the eyepiece 2, the compensation plate 3, the objective lens 4 and the reflector 5 are fixed on the adjustment device in sequence. The parallel light emitted by the interferometer 1 passes through the eyepiece 2, the compensation plate 3 and the objective lens 4 in sequence, and is reflected by the reflector 5 and then returns along the original optical path. The returned test light and the standard light of the interferometer 1 interfere with each other to obtain interference fringes. The system aberration of the interference fringes is the aberration of the beam expansion system. The eyepiece 2 and / or the objective lens 4 are repeatedly corrected based on the system aberration of the interference fringes until the system aberration of the interference fringes meets the use requirements in step S1.

[0031] Preferably, the eyepiece 2 and / or the objective lens 4 are repeatedly corrected, that is, the thickness and curvature of the eyepiece 2 and / or the objective lens 4 are repeatedly reprocessed, so that the aberration of the beam expansion system meets the design value. In the prior art, the processing accuracy of the eyepiece 2 and the objective lens 4 cannot be guaranteed to be processed to the preset parameters in one time, so it is necessary to repeatedly perform the surface correction.

[0032] Furthermore, the interferometer 1 is a visible light interferometer. The reflector 5 is a plane reflector.

[0033] Step S4: After the profile correction of the eyepiece 2 and / or the objective lens 4 in the beam expansion system is completed, the compensation plate 3 is removed from the adjustment device to complete the adjustment of the beam expansion system.

[0034] The adjustment method of the present invention solves the processing adjustment problem caused by the inconsistency between the wavelength used by the near-infrared beam expansion system and the adjustment wavelength by designing and adding the compensation plate 3.

[0035] The above basic examples of the present invention and their further selected examples can be freely combined to form multiple embodiments, all of which are embodiments that can be adopted and claimed by the present invention. In the scheme of the present invention, each selected example can be arbitrarily combined with any other basic example and selected example. Those skilled in the art will know that there are many combinations.

[0036] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for assembling and adjusting a transmission-type near-infrared beam expansion system, characterized in that: The adjustment method comprises: S1: Based on usage requirements, completing the optical design of a beam expansion system at a usage wavelength, wherein the beam expansion system at least includes an eyepiece (2) and an objective lens (4); The use requirements of step S1 include the design aberration of the beam expansion system; after the optical design of the beam expansion system is completed in step S1, the thickness, curvature and spacing parameters of the eyepiece (2) and the objective lens (4) are fixed; S2: Under the wavelength adjustment condition, a compensating plate (3) is added between the eyepiece and the objective lens of the beam expansion system, and based on the system aberration condition preset in step S1, a thickness value of the compensating plate (3) is obtained; The thickness of the compensation plate is calculated in the optical design software: first, the beam expansion system design is completed at the wavelength used, and the curvature radius and thickness parameters of the eyepiece and objective lens, as well as the distance between the eyepiece and the objective lens are solidified. Secondly, the system wavelength is changed to the adjustment wavelength, and a parallel plate is added between the eyepiece and the objective lens. Its thickness value is set as the only variable. Finally, it is iterated until the system aberration is consistent with the wavelength used, that is, the compensation plate design is completed, and the thickness value of the parallel plate is the thickness value of the compensation plate. In the step S2, the compensating plate (3) is arranged close to the eyepiece (2); S3: The interferometer (1), the eyepiece (2), the compensation plate (3), the objective lens (4) and the reflector (5) are fixed on the adjustment device in sequence, and the parallel light emitted by the interferometer (1) passes through the eyepiece (2), the compensation plate (3) and the objective lens (4) in sequence, and is reflected by the reflector (5) and then returns along the original optical path, and the returned test light interferes with the standard light of the interferometer to obtain interference fringes and their system aberrations, and the eyepiece (2) and / or the objective lens (4) are repeatedly corrected based on the system aberrations of the interference fringes until the system aberrations of the interference fringes meet the use requirements in step S1; The profile correction refers to repeatedly reprocessing the thickness and curvature of the eyepiece (2) and / or the objective lens (4); The interferometer (1) is a visible light interferometer; the reflector (5) is a plane reflector; S4: After the profile correction of the eyepiece (2) and / or the objective lens (4) in the beam expansion system is completed, the compensation plate (3) is removed from the adjustment device to complete the adjustment of the beam expansion system.

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