Device and method for precision measuring focal length of long-focus lens

Abstract

The invention discloses a focal distance measuring device and the measuring method for long focal distance lens. The laser leading out from the strong laser source or other laser with the same frequency are gathered by lends after being combined into parallel ray through extender device, then transmitted out from the large aperture lens. Then adjusts the sliding board till the emitted ray of the measured lens is parallel ray, thus the measured focus must be at the proper position. The localization of the focus and the diameter size measurement can be completed with an amplified and labeled surface array CCD measuring head. The focal distance L can be measured with paten 01108773.0. The invention needs no large expensive collimating pipe, uses the reversal method, thus the measured lends is changed into lend with parallel pipe.

Description

1. Technical field [0001] The invention relates to a device for accurately measuring the focal length of a long focal length lens and a testing method thereof, and belongs to the technical field of strong lasers. 2. Background technology [0002] The concentrating lenses used in the field of strong laser technology are large, and the focal length is also very long, nearly 20 meters. Generally, multiple channels are used in parallel and require spatial filtering, so focal length measurement is very important. The commonly used method is still the traditional optical method for measuring general lenses, that is, using a collimated light tube to generate parallel light, and after the lens is focused, use a knife-edge instrument to measure the size and position of the focal length, and then use a baseline ruler to measure the distance. Because this method is very intuitive when measuring general lenses, there are not many special discussions. It is generally mentioned in the use...

AI Technical Summary

Problems solved by technology

But it has become a problem in the application of strong laser, because the lens aperture reaches φ500mm. If the traditional method is used, the length of the collimator light tube will reach about 7 meters due to the manufacturing process. Such an optical bench must be specially made. Not only expensive, but also very troublesome to adjust, install and use

In addition, it is very troublesome to find the focus of the knife-edge instrument, because this method cannot measure continuously and every point must be manually adjusted, which is difficult to automate

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