The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 30, 2025
Filed:
Jun. 14, 2021
Nippon Sheet Glass Company, Limited, Tokyo, JP;
Hiroaki Kato, Kanagawa, JP;
Satoshi Taniguchi, Tokyo, JP;
Tokushi Kaneko, Kanagawa, JP;
Tsuyoshi Yamane, Kanagawa, JP;
Kenichi Sato, Kanagawa, JP;
Tomitaka Takagi, Tokyo, JP;
NIPPON SHEET GLASS COMPANY, LIMITED, Tokyo, JP;
Abstract
A rod lens arrayincludes a plurality of gradient-index rod lensesarrayed to have optical axes parallel to each other, and forms an erecting equal-magnification image. The gradient-index rod lenseseach have a refractive-index distribution in a radial direction thereof. The refractive-index distribution n(r) is approximated by n(r)=n·{1−(A/2)·r}, where a refractive index at a center of the gradient-index rod lensis represented by n, a refractive-index distribution constant of the gradient-index rod lensis represented by √A, and a distance from the center of the gradient-index rod lensis represented by r. The gradient-index rod lenshas an aperture angle θ of 3 to 6°, the aperture angle θ represented by θ=sin(n√A·r), where a radius of the gradient-index rod lens is represented by r. The rod lens arrayhas an imaging distance of 45 to 75 mm and a depth of field of 1.5 to 3.0 mm with value of modulation transfer function (MTF) of 30% or more at a spatial frequency of 6 lp/mm.