Method and device for measuring axial gaps of differential confocal lens set

A differential confocal and axial gap technology, applied in the direction of measuring devices, optical devices, instruments, etc., to achieve the effect of achieving tomographic capability, high stability, and improving measurement accuracy

Active Publication Date: 2010-06-30
BEIJING INSTITUTE OF TECHNOLOGYGY
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Problems solved by technology

[0014] The purpose of the present invention is to solve the problem of non-contact high-precision measurement of the axial gap in the mirror group, and propose a method and device for accurately measuring the axial gap in the mirror group using differential confocal technology

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  • Method and device for measuring axial gaps of differential confocal lens set
  • Method and device for measuring axial gaps of differential confocal lens set
  • Method and device for measuring axial gaps of differential confocal lens set

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Embodiment 1

[0051] Such as figure 2 , Figure 5 and Figure 7 As shown, the axial gap measurement method of the differential confocal lens group, the measurement steps are:

[0052] At first, start the measurement software in the main control computer 33, input the design parameters of the mirror group 4 under test, including the radius of curvature of each lens in the mirror group, from left to right: r 1 =195.426mm, r 2 =-140.270mm, r 3 =-140.258mm, r 4 =-400.906mm; Refractive index, from left to right: n 0 = 1, n 1 = 1.5143, n 2 = 1, n 3 = 1.668615.

[0053] Then, turn on the collimated light source 26, and the parallel light emitted by it passes through the annular pupil 1 with a light transmission diameter of 6.8mm-9.6mm, passes through the beam splitting system 2, and converges at the focal point 5 through the objective lens 3 with a top focal length of 35mm. A hollow light cone is formed, and the light is reflected by the surface of the inner lens of the mirror group 4 u...

Embodiment 2

[0064] Such as image 3 , Figure 5 and Figure 7 As shown, the embodiment one figure 2 The differential confocal system in is replaced by image 3 The differential confocal system in the above can constitute the second embodiment. The difference from Embodiment 1 is that after the light enters the differential confocal system 6, the beam splitter 18 divides the light into two paths, the transmitted light illuminates the pre-focus CCD detector 16 after passing through the first lens 17, and the reflected light passes through the second lens The back 15 illuminates the back focus CCD detector 14 . The remaining measurement methods and devices are the same as those in Example 1.

Embodiment 3

[0066] Such as Figure 4 , Figure 5 and Figure 7 As shown, the embodiment one figure 2 The differential confocal system in is replaced by Figure 4 The differential confocal system in the above can constitute the second embodiment. The difference from Embodiment 1 is that after the light enters the differential confocal system 6, the beam splitter 25 divides the light into two paths, and the transmitted light passes through the first lens 24 and the pre-focus microscopic objective lens 23 and passes through the first CCD detector 22. The surface is imaged, and the reflected light is imaged on the surface of the second CCD detector 19 after passing through the second lens 21 and the after-focus microscopic objective lens 20 . The remaining measurement methods and devices are the same as those in Example 1.

[0067] This embodiment realizes the non-contact high-precision measurement of the axial gap in the mirror group through a series of measures, realizes the method an...

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Abstract

The invention belongs to the technical field of optical precise measurement, in particular to a method and a device for measuring the axial gaps of a differential confocal lens set. The method comprises the following steps of: firstly, positioning the surfaces of various lens in the lens set with high precision by a differential confocal focusing principle to acquire position coordinates of a differential confocal measuring head in various positioning points; and then, sequentially calculating various axial gaps in the lens set by utilizing a beam track recurrence formula. Meanwhile, a circular pupil is introduced in a measuring light path to shield paraxial beams a hollow measuring light cone is formed so as to eliminate the influence of image difference on the measuring result. The invention realizes the non-contact high-precision positioning of the surfaces of the lens in the lens set by using the differential confocal light cone, has the advantages of long working distance, high measuring speed without dismounting the tested lens set in the measuring process, and the like, and can be used for the non-contact high-precision measurement of the axial gaps in the lens set.

Description

technical field [0001] The invention belongs to the technical field of optical precision measurement, and can realize the non-contact high-precision measurement of the axial gap in the mirror group without disassembling the mirror group. technical background [0002] In the field of optics, the measurement of the axial gap in the lens group is of great significance. During the assembly process of high-performance optical systems such as lithography objective lenses and aerospace cameras, it is necessary to precisely adjust the lens axial gap, radial offset and optical axis deflection angle according to the curvature radius and refractive index of the lens in the lens. Taking the objective lens of lithography machine as an example, the axial gap deviation of each single lens will cause spherical aberration, astigmatism, coma, distortion and other aberrations of the lithography objective lens, which will affect the imaging quality of the objective lens. In order to control th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01B11/14
Inventor 赵维谦孙若端邱丽荣史立波刘大礼沙定国
Owner BEIJING INSTITUTE OF TECHNOLOGYGY
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