US4595290A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Device for measuring light incident on an optical system
Assignee: Canon Inc
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Filing: 1981-07-14
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Granted: 1986-06-17
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Expires: 2001-07-14
Abstract
Abstract This invention provides a device for measuring light incident on an optical system. This device includes an optical system defining an optical path, a beam splitter and a photo detector. The beam splitter has a relief type diffraction lattice having a plurality of semireflecting surfaces periodically arranged and included in a transparent body. The diffraction lattice is arranged to split a portion of the incident light by its effect of reflection/diffraction and its beam splitting efficiency having a predetermined distribution within the lattice area. The diffracted light from the diffraction lattice is directed to the photo detector.
Inventors
- 👤 Noriyuki Nose
- 👤 Kiyonobu Endo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 06:07
CPC Classifications
G; G02; G02B; G02B27/00; G02B27/10; G02B27/108; G02B27/1086; G03; G03B; G03B7/00; G03B7/08; G03B7/099; G03B7/0993; G03B7/0997; G03B7/09971; G03B7/09976
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
100 words
A device for mesuring light incident on an optical system, comprising: an optical system for defining an optical path; a beam splitter having a relief type diffraction lattice including a plurality of semi-reflecting oblique surfaces periodically arranged on a tranparent body, said diffraction lattice being disposed along the optical path to diffract a portion of the incident light and transmit another portion of the incident light, wherein the ratio of light diffraction to light transmission has a predetermined non-uniform distribution and changes continuously over the lattice area; and photo detector means for detecting the light diffracted from said diffraction lattice.
Claim 2
Independent Claim
100 words
A device for mesuring light incident on an optical system, comprising: an optical system for defining an optical path; a beam splitter having a relief type diffraction lattice including a plurality of semi-reflecting oblique surfaces periodically arranged on a tranparent body, said diffraction lattice being disposed along the optical path to diffract a portion of the incident light and transmit another portion of the incident light, wherein the ratio of light diffraction to light transmission has a predetermined non-uniform distribution and changes continuously over the lattice area; and photo detector means for detecting the light diffracted from said diffraction lattice.
Claim 3
Independent Claim
130 words
A device for measuring light incident on an optical system, comprising: an optical system for defining an optical path; a beam splitter including a plurality of semi-reflecting obliquie surfaces arranged on a transparent body and in said optical path, the reflectivity of said semi-reflecting oblique surfaces having a predetermined non-uniform distribution within the area in which said semi-reflecting surfaces are provided; wherein the reflectivity of said semi-reflecting surfaces changes stepwise at least over a part of the area in which said semi-reflecting surfaces are provided, and wherein the difference in reflectivity ΔR(%) between the neighboring sub-areas having different reflectvities satisifies the following condition: ΔR≦3.1×ΔL+1.5 wherein, ΔL(mm) is the distance between two points belonging to the respective sub-areas; and Photo detector means for receiving the light reflected from said beam splitter.
Claim 4
Independent Claim
130 words
A device for measuring light incident on an optical system, comprising: an optical system for defining an optical path; a beam splitter including a plurality of semi-reflecting obliquie surfaces arranged on a transparent body and in said optical path, the reflectivity of said semi-reflecting oblique surfaces having a predetermined non-uniform distribution within the area in which said semi-reflecting surfaces are provided; wherein the reflectivity of said semi-reflecting surfaces changes stepwise at least over a part of the area in which said semi-reflecting surfaces are provided, and wherein the difference in reflectivity ΔR(%) between the neighboring sub-areas having different reflectvities satisifies the following condition: ΔR≦3.1×ΔL+1.5 wherein, ΔL(mm) is the distance between two points belonging to the respective sub-areas; and Photo detector means for receiving the light reflected from said beam splitter.
Claim 5
Independent Claim
109 words
A device for measuring light incident on an optical system, comprising: an optical system defining an optical path; a beam splitter disposed to splita portion of the incident light and composed of a great number of reflecting dots dispersed on a plurality of oblique surfaces on a transparent body, wherein the size of the individual reflecting dots are extremely small as compared with the area of said beam splitter and the ratio of the area of said reflecting dots to a unit area changes over the area in which said reflecting dots are provided; and photo detector means to which the light split from said beam splitter is directed.
Claim 6
Independent Claim
109 words
A device for measuring light incident on an optical system, comprising: an optical system defining an optical path; a beam splitter disposed to splita portion of the incident light and composed of a great number of reflecting dots dispersed on a plurality of oblique surfaces on a transparent body, wherein the size of the individual reflecting dots are extremely small as compared with the area of said beam splitter and the ratio of the area of said reflecting dots to a unit area changes over the area in which said reflecting dots are provided; and photo detector means to which the light split from said beam splitter is directed.
Claim 7
Dependent Claim
32 words
A light measuring device according to claim 3, wherein the size of the individual reflecting dots varies from one sub-area to another over the area in which said reflecting surfaces are provided.
Claim 8
Dependent Claim
31 words
A light measuring device according to claim 3, wherein the density of said reflecting dots varies from one sub-area to another over the area in which said reflecting surfaces are provided.
Claim 9
Dependent Claim
30 words
A light measuring device according to claim 3, wherein the difference in reflectivity between the reflecting dots and the obliquie surface other than said reflecting dots is less than 5%.
Claim 10
Dependent Claim
19 words
A light measuring device according to claim 2, 3, wherein said semi-reflecting surfaces are covered by a transparent body.
Claim 11
Dependent Claim
35 words
A light measuring device according to claim 1, 3, wherein said optical system is an image forming optical system and said beam splitter is disposed at or near the image plane of said optical system.
Claim 12
Independent Claim
110 words
A device for measuring light incident on an optical system, comprising: an optical system for defining an optical path; a beam splitter incuding a plurality of semi-reflecting oblique surfaces arranged on a transparent body and in said optical path, the reflectivity of said semi-reflecting oblique surface having a predetermined non-uniform distribution within the area in which said semi-reflecting surfaces are provided, and wherein the reflectivity of said semi-reflecting surfaces changes continuously at least over a part of the area in which said semi-reflecting surfaces are provided, with the rate of change being less than 31.3% per mm; and photo detector means for receiving the light reflected from said beam splitter.
Claim 13
Independent Claim
110 words
A device for measuring light incident on an optical system, comprising: an optical system for defining an optical path; a beam splitter incuding a plurality of semi-reflecting oblique surfaces arranged on a transparent body and in said optical path, the reflectivity of said semi-reflecting oblique surface having a predetermined non-uniform distribution within the area in which said semi-reflecting surfaces are provided, and wherein the reflectivity of said semi-reflecting surfaces changes continuously at least over a part of the area in which said semi-reflecting surfaces are provided, with the rate of change being less than 31.3% per mm; and photo detector means for receiving the light reflected from said beam splitter.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-06-16 | 1989-12-16 | 1990-06-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-06-16 | 1993-12-16 | 1994-06-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-06-16 | 1997-12-16 | 1998-06-17 | $7700.00 | Window Closed / Lapsed |