A device for measuring the optical power of a free-form spectacle lens based on a two-dimensional Ronchi grating

Abstract

A device for measuring the optical power of a free-form spectacle lens based on a two-dimensional Ronchi grating includes: a light source, a collimating objective lens, a two-dimensional Ronchi grating, a sample mirror to be tested, a projection receiving screen, an imaging objective lens, and a photodetector. The parallel light passes through the sample mirror to be tested, and then passes through the two-dimensional Ronchi grating, projecting the distorted grating stripes on the receiving screen, and then taking the receiving screen as the object plane, using the imaging objective lens and photodetector to process the grating on the receiving screen Imaging, combined with later data processing, obtains the optical power of the lens under test. The invention has a simple and stable structure, and the processing technology is easy to realize. Compared with the existing free-form surface lens focal power measurement technology, the invention can simplify the installation and adjustment of the whole system and realize mass production.

Description

technical field [0001] The invention relates to a detection device for optical parameter measurement, in particular to a free-form spectacle lens power measurement device based on a two-dimensional Ronchi grating, which is suitable for the free-form spectacle lens power measurement. Background technique [0002] At present, the detection of the lens is mainly carried out by the automatic lens meter. The automatic lens meter has become one of the necessary instruments in the eyewear industry. The automatic focal meter is usually composed of optical system, precision machinery, photoelectric detection device (usually CCD sensor) and electrical control, involving knowledge of light, mechanics, electricity and other aspects. The automatic focal meter uses the single-point measurement method. It selects four light spots symmetrically near the main optical axis of the lens, uses an area array image sensor to collect images of the four light spots, and calculates the vertex power...

AI Technical Summary

Problems solved by technology

However, in the reported literature, a one-dimensional Ronchi grating is used, so in order to obtain the focal power information of the measured lens, a mechanical rotating device must be used to rotate the one-dimensional Ronchi grating (generally by 90°)

Through the superposition of the two images before and after rotation, a two-dimensional grid division of the lens under test is formed, and then the measurement is carried out, so the measurement time of this method is longer

In addition, in the reported literature, the imaging objective lens is used to directly focus the grating passing through the lens under test onto the photodetector. Therefore, when the focal lengths of the tested samples are different, the imaging objective lens must also have different focal lengths—that is, It is said that the system needs to use a zoom objective lens, which increases the complexity of the system

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