Pentaprism combination ultralong focal-length measurement method and apparatus

Abstract

The invention belongs to the technical field of optical precision measurement and relates to a measuring method of an ultralong focal length of a penta prism combination, and a measuring device thereof. The method integrates a penta prism focus fixing method and an ultralong focal length measuring technology of a composite lens and helps realize low-cost and high-precision ultralong focal length measurement of large-caliber lenses. The method helps transform a focus fixing process in an optical axis direction into a variance measurement process of an imaging position in a vertical optical axis direction by using the penta prism to refract an optical path, and is further combined with the ultralong focal length measuring technology of the composite lens to compress length of the optical path and improve measurement resolution. The measuring device comprises a light source, the penta prism, a reference lens, an alignment target, a CCD detector and a collimator mirror, has the advantages of simple optical path structure, less aberration introduced by an optical component, less systematic error, high measurement sensitivity, high resistance to ambient interference, and can be applied to detection of the ultralong focal length lens and high-precision focal length measurement during assembling an optical system.

Description

technical field

[0001] The invention belongs to the technical field of optical precision measurement and can be used for the detection of ultra-long focal length lenses and the high-precision focal length measurement in the assembly process of optical systems. technical background

[0002] In recent years, ultra-long focal length lenses have been widely used in large-scale optical systems such as high-energy lasers and astronomical telescopes. The processing, testing and assembly of such large-scale lenses are very difficult. As an important parameter of ultra-long focal length lenses, its focal length measurement has always been a difficult point in the field of optical measurement. The main factors are: long focal depth, difficult to achieve accurate focusing; long focal length, difficult to measure length precisely; long optical path, measurement is easily affected by environmental interference .

[0003] Due to the influence of the above factors, it is difficult for the...

Examples

Embodiment

[0043] Such as figure 2 Shown, a kind of pentaprism combined ultra-long focal length measurement method, its measurement steps are:

[0044] (a) Use a near-infrared 1064 μm laser to irradiate a slit as the alignment target 9. After the outgoing light is converged by the reference lens 5 and refracted by the pentaprism 2, it is imaged on the CCD detector 11 through the collimator 12. At this time, the translation stage 13 drives the alignment target 9 to scan and move in the direction of the optical axis of the reference lens 5, and when it moves to a new scanning position, it judges whether it coincides with the second focus position 8 by translating the pentaprism 2.

[0045] The judgment method is as follows: Figure 4 As shown, when there is a defocus amount 18 between the scanning position where the slit is aligned with the target 9 and the second focus position 8, the translation stage 17 drives the pentaprism 2 to translate in the direction of the CCD detector 11, and th...

technical field

[0001] The invention belongs to the technical field of optical precision measurement and can be used for the detection of ultra-long focal length lenses and the high-precision focal length measurement in the assembly process of optical systems. technical background

[0002] In recent years, ultra-long focal length lenses have been widely used in large-scale optical systems such as high-energy lasers and astronomical telescopes. The processing, testing and assembly of such large-scale lenses are very difficult. As an important parameter of ultra-long focal length lenses, its focal length measurement has always been a difficult point in the field of optical measurement. The main factors are: long focal depth, difficult to achieve accurate focusing; long focal length, difficult to measure length precisely; long optical path, measurement is easily affected by environmental interference .

[0003] Due to the influence of the above factors, it is difficult for the...

Examples

Embodiment

[0043] Such as figure 2 Shown, a kind of pentaprism combined ultra-long focal length measurement method, its measurement steps are:

[0044] (a) Use a near-infrared 1064 μm laser to irradiate a slit as the alignment target 9. After the outgoing light is converged by the reference lens 5 and refracted by the pentaprism 2, it is imaged on the CCD detector 11 through the collimator 12. At this time, the translation stage 13 drives the alignment target 9 to scan and move in the direction of the optical axis of the reference lens 5, and when it moves to a new scanning position, it judges whether it coincides with the second focus position 8 by translating the pentaprism 2.

[0045] The judgment method is as follows: Figure 4 As shown, when there is a defocus amount 18 between the scanning position where the slit is aligned with the target 9 and the second focus position 8, the translation stage 17 drives the pentaprism 2 to translate in the direction of the CCD detector 11, and th...

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