JPS57161843A - Focusing glass - Google Patents
Focusing glassInfo
- Publication number
- JPS57161843A JPS57161843A JP4761981A JP4761981A JPS57161843A JP S57161843 A JPS57161843 A JP S57161843A JP 4761981 A JP4761981 A JP 4761981A JP 4761981 A JP4761981 A JP 4761981A JP S57161843 A JPS57161843 A JP S57161843A
- Authority
- JP
- Japan
- Prior art keywords
- image
- prism
- grating
- coloring
- eye
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 239000011521 glass Substances 0.000 title abstract 2
- 238000004040 coloring Methods 0.000 abstract 2
- 238000005259 measurement Methods 0.000 abstract 2
- 230000003287 optical effect Effects 0.000 abstract 2
- 230000011514 reflex Effects 0.000 abstract 1
Classifications
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
- G03B13/00—Viewfinders; Focusing aids for cameras; Means for focusing for cameras; Autofocus systems for cameras
- G03B13/18—Focusing aids
- G03B13/24—Focusing screens
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Viewfinders (AREA)
- Diffracting Gratings Or Hologram Optical Elements (AREA)
Abstract
PURPOSE:To prevent an image from coloring by providing a part, which slants partially in the reverse direction, to the tooth part of a saw-tooth prism which is used for single-lens reflex focusing glass and operates as a diffraction grating. CONSTITUTION:A multiple eschelette type grating as a substitute for a split image prism has high precision because of prism operation and diffraction grating operation and also has such an advantage that an image never gets dark over a wide F-number range, but diffraction operation may cause an image to color in a large-F-number range and when an eye is shifted from a finder optical axis. For this purpose, parts d3-d6 which slant in the reverse direction are provided in contact with slanting parts d1 and d2 for distance measurement in one cycle of the grating. Consequently, the wavelength dependency of the optical path is reduced as much as possible to reduce the coloring of the image, so that the distance measurement is facilitated regardless of an F value and the position of the eye.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4761981A JPS57161843A (en) | 1981-03-31 | 1981-03-31 | Focusing glass |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4761981A JPS57161843A (en) | 1981-03-31 | 1981-03-31 | Focusing glass |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS57161843A true JPS57161843A (en) | 1982-10-05 |
| JPH0332054B2 JPH0332054B2 (en) | 1991-05-09 |
Family
ID=12780226
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4761981A Granted JPS57161843A (en) | 1981-03-31 | 1981-03-31 | Focusing glass |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS57161843A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6590709B1 (en) * | 1997-04-18 | 2003-07-08 | Minolata Co., Ltd. | Diffractive optical element and method of manufacturing a mold |
| JP2006285011A (en) * | 2005-04-01 | 2006-10-19 | Canon Inc | Diffraction optical element, metal mold for molding diffraction optical element, method for manufacturing diffraction optical element, and method for manufacturing metal mold for molding diffraction optical element |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9341249B2 (en) * | 2011-09-02 | 2016-05-17 | Aktiebolaget Skf | Spacer for rolling bearing, notably used in a wind turbine |
-
1981
- 1981-03-31 JP JP4761981A patent/JPS57161843A/en active Granted
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6590709B1 (en) * | 1997-04-18 | 2003-07-08 | Minolata Co., Ltd. | Diffractive optical element and method of manufacturing a mold |
| JP2006285011A (en) * | 2005-04-01 | 2006-10-19 | Canon Inc | Diffraction optical element, metal mold for molding diffraction optical element, method for manufacturing diffraction optical element, and method for manufacturing metal mold for molding diffraction optical element |
| JP4587172B2 (en) * | 2005-04-01 | 2010-11-24 | キヤノン株式会社 | Diffractive optical element, diffractive optical element manufacturing method, and diffractive optical element molding die manufacturing method |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0332054B2 (en) | 1991-05-09 |
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