Method and apparatus for measuring light transmissivity

Abstract

A method and apparatus for enabling an inexpensive and easy measurement of light transmittance of an optical lens having refractive power with excellent accuracy is disclosed. The method for measuring light transmittance comprises deriving light transmittance of a lens 30 to be examined from a value corresponding to a ratio of an intensity of measuring light L detected by a means for detecting light 50 when the lens 30 to be examined is placed in a path of the measuring light L emitted from a light source 10 and reaching the means for detecting light 50 and the measuring light L passes through the lens 30 to be examined to an intensity of the measuring light L detected by the means for detecting light 50 when the lens 30 to be examined is not placed in the path of the measuring light L and the measuring light L does not pass through the lens 30 to be examined, wherein the measuring light L passes through the lens 30 to be examined in a condition such that rays of the measuring light L converge at or in a vicinity of a position where the lens 30 to be examined is disposed. <IMAGE>

Description

technical field [0001] The present invention relates to a method according to claim 1 for measuring the light transmittance of an optical lens, such as eyeglasses, more conveniently, and to an apparatus according to claim 3 for carrying out the method according to the invention. Background technique [0002] In optical shops, as one of various inspections on the performance of glasses, it is sometimes necessary to check the light transmittance of the glasses for ultraviolet light or visible light. [0003] As a method of measuring the light transmittance, there is known a method in which the light transmittance is accurately measured by using an integrating sphere in a photometric system so that the measured value can be measured even when the measurement light is diverged or converged by the lens to be inspected. No error occurs in . However, integrating spheres are relatively expensive, and thus it is difficult to widely popularize integrating spheres in optical shops. ...

AI Technical Summary

Problems solved by technology

When the cross-sectional area of ​​the measuring light beam is quite large and the difference in diopter is large, the difference in the attenuation of the luminous flux cannot be ignored, resulting in errors in the measurement

[0014] Therefore, in the device for measuring the light transmittance disclosed in Japanese Patent Application Laid-Open No. Hei 11 (1999)-211617, in order to obtain the light transmittance of the lens to be inspected, the diopter of the lens to be inspected must be known in advance, which has a great influence on the measurement. has a significant detrimental effect on the convenience of

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