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US5418356A
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Reading optical system
Assignee: Pentax Corp
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Filing: 1994-02-16
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Granted: 1995-05-23
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Expires: 2014-02-16
Abstract
Abstract A reading optical system is provided which includes a diaphragm and a positive meniscus lens having a concave surface, wherein the concave surface is located on the side of the lens nearest to the diaphragm, and wherein the following relationship exists; 0.15<(d1+d2)/f<0.41 0.35<(d1+d2)/|r1|<0.85 wherein "(d1+d2)" designates the sum of the distance between the diaphragm and the lens and the thickness of the lens, "f" the focal length the meniscus lens, and "r1" the radius of curvature of a surface located on an objective side of the meniscus lens.
Inventors
- 👤 Masahito Takano
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 23:03
CPC Classifications
G; G06; G06K; G06K7/00; G06K7/10; G06K7/10544; G06K7/10554; G06K7/10594; G06K7/10683; G06K7/10702
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
86 words
A reading optical system comprising: a diaphragm and a positive meniscus lens having a concave surface, wherein the concave surface is located on a side of a lens nearest to the diaphragm, and wherein the following relationship exists; 0.15<(d1+d2)/f<0.41 0.35<(d1+d2)/|r1|<0.85 wherein "(d1+d2)" designates a sum of a distance between the diaphragm and a lens and a thickness of the lens, "f" the focal length of the meniscus lens, and "r1" a radius of curvature of a surface located on an objective side of the meniscus lens.
Claim 2
Dependent Claim
86 words
A reading optical system comprising: a diaphragm and a positive meniscus lens having a concave surface, wherein the concave surface is located on a side of a lens nearest to the diaphragm, and wherein the following relationship exists; 0.15<(d1+d2)/f<0.41 0.35<(d1+d2)/|r1|<0.85 wherein "(d1+d2)" designates a sum of a distance between the diaphragm and a lens and a thickness of the lens, "f" the focal length of the meniscus lens, and "r1" a radius of curvature of a surface located on an objective side of the meniscus lens.
Claim 3
Dependent Claim
16 words
The reading optical system of claim 1, wherein an object to be read is linear data.
Claim 4
Dependent Claim
15 words
The reading optical system of claim 2, wherein the linear data is a bar code.
Claim 5
Dependent Claim
23 words
The reading optical system of claim 1, wherein the diaphragm and the meniscus lens are located in this order from the objective side.
Claim 6
Dependent Claim
23 words
The reading optical system of claim 1, wherein the meniscus lens and the diaphragm are located in this order from the objective side.
Claim 7
Dependent Claim
83 words
A bar code reader comprising: a light source which emits light onto a bar code; a reading optical system which forms an image of the light reflected from the bar code; and, a line sensor provided at an image forming position of the reading optical system where the image is formed, wherein the reading optical system includes a diaphragm and a positive meniscus lens, a surface of the positive meniscus lens nearest to the diaphragm being concave, and wherein a following relationship exists;
Claim 8
Dependent Claim
83 words
A bar code reader comprising: a light source which emits light onto a bar code; a reading optical system which forms an image of the light reflected from the bar code; and, a line sensor provided at an image forming position of the reading optical system where the image is formed, wherein the reading optical system includes a diaphragm and a positive meniscus lens, a surface of the positive meniscus lens nearest to the diaphragm being concave, and wherein a following relationship exists;
Claim 9
Dependent Claim
48 words
15<(d1+d2)/f<0.41 0.35<(d1+d2)/|r1|<0.85 wherein "(d1+d2)" designates a sum of a distance between the diaphragm and a lens and the thickness of the lens, "f" the focal length of a meniscus lens, and "r1" a radius of curvature of a surface located on an objective side of the meniscus lens.
Claim 10
Dependent Claim
48 words
15<(d1+d2)/f<0.41 0.35<(d1+d2)/|r1|<0.85 wherein "(d1+d2)" designates a sum of a distance between the diaphragm and a lens and the thickness of the lens, "f" the focal length of a meniscus lens, and "r1" a radius of curvature of a surface located on an objective side of the meniscus lens.
References Cited (Backward Citations)
US4818856A
Cited
JPH04191716A
Cited
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