Method and device for measuring modulation transfer functions of optic lenses through infinite conjugated light paths

Abstract

The invention relates to a method and a device for measuring modulation transfer functions of optic lenses through infinite conjugated light paths. The method comprises the following steps of, firstly, distributing a plurality of digital cameras on the side of the object space of a lens to be measured according to the measuring requirements of the lens to be measured, and aligning the optical axises of the digital cameras to the principle point of the object space of the lens to be measured; secondly, sequentially placing a reticle, a diffusion plate and a backlight plate on the side of the image space of the lens to be measured from near to far in the axis direction of the lens to be measured; thirdly, adjusting the reticle and enabling the reticle to be positioned on the focal plane of the lens to be measured; fourthly, selecting the image of one resolution cell pattern in the center of every digital camera to compute out the MTF (modulation transfer function) values corresponding to different line pair densities; fifthly, generating the modulation transfer function curves in the meridian direction and the sagittal direction of the lens to be measured in different view positions. The method and the device for measuring the modulation transfer functions of the optic lenses through the infinite conjugated light paths can be applied to measuring lenses with large field angles and solve the problem that measuring the lenses through existing finite conjugated optical systems is large in errors.

Description

technical field [0001] The invention relates to the field of optoelectronics, in particular to a method and device for measuring the modulation transfer function of an optical lens with an infinite conjugate optical path, which can be used to measure wide-angle lenses, fisheye lenses, etc. up to 180°) lens. Background technique [0002] Clarity is the most important indicator of optical lens, and the modulation transfer function curve is a general scientific method to describe the clarity of optical lens. At present, the most common method used by lens manufacturers to obtain the modulation transfer function curve is the back projection visual method. The principle of this method is: the reticle engraved with the discrimination rate pattern is located outside the focal plane of the lens under test and close to the focal plane, and the auxiliary lighting source is evenly irradiated on the reticle. By adjusting the positions of the reticle and the lens under test, the enlarg...

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Problems solved by technology

[0007] The purpose of the present invention is to overcome above shortcoming, provide a kind of method and the device that are used to realize the modulation transfer function of the optical lens of a kind of infinite conjugate light path measurement, this method and device can be used for measuring the lens (such as wide-angle lens) that field angle is big , fisheye lens), which solves the problem of large errors in the measurement of the above-mentioned lenses by the current finite conjugate optical system. Inspection requirements for mass production of lenses, easy to popularize and apply

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