JPS5560934A - Color band removing focus adjusting method in overhead projector - Google Patents
Color band removing focus adjusting method in overhead projectorInfo
- Publication number
- JPS5560934A JPS5560934A JP13395978A JP13395978A JPS5560934A JP S5560934 A JPS5560934 A JP S5560934A JP 13395978 A JP13395978 A JP 13395978A JP 13395978 A JP13395978 A JP 13395978A JP S5560934 A JPS5560934 A JP S5560934A
- Authority
- JP
- Japan
- Prior art keywords
- extension line
- axial center
- projecting
- lens
- projecting lens
- 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.)
- Pending
Links
Landscapes
- Overhead Projectors And Projection Screens (AREA)
- Automatic Focus Adjustment (AREA)
- Focusing (AREA)
Abstract
PURPOSE: To prevent the production of color bands by elevating a projecting lens perpendicularly along the axial center extension line of the center part of an eccentric Fresnel lens and moving a light source lamp on said axial center extension line along with its elevation.
CONSTITUTION: In the case of matching the focus of projecting images, a projecting lens 15 is elevated in the perpendicular direction along the axial center extension line b of an eccentric Fresnel lens center part 12a while the parallel relation with a stage 11 is being maintained and is so vertically moved that the center 15a of the projecting lens 15 always passes the axial center extension line b. Next, when a light source lamp 14 is retreated down to the e position while, e.g., the projecting lens 15 is being lowered down to the d position on the axial center extension line b, the luminous flux of the projecting system condensed by the Fresnel lens 12 assumes the C state and therefore the whole of the luminous flux C passes through the projecting lens 15. Hence, on color bands are produced in the images projected onto a screen 17 and the good images are formed. In this way, the production of color bands may be prevented.
COPYRIGHT: (C)1980,JPO&Japio
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13395978A JPS5560934A (en) | 1978-10-31 | 1978-10-31 | Color band removing focus adjusting method in overhead projector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13395978A JPS5560934A (en) | 1978-10-31 | 1978-10-31 | Color band removing focus adjusting method in overhead projector |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS5560934A true JPS5560934A (en) | 1980-05-08 |
Family
ID=15117072
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP13395978A Pending JPS5560934A (en) | 1978-10-31 | 1978-10-31 | Color band removing focus adjusting method in overhead projector |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5560934A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0304800B1 (en) * | 1987-08-24 | 1993-04-14 | ProCent Patent- und Verwaltungs AG | Overhead projector |
| US5296882A (en) * | 1992-12-21 | 1994-03-22 | Minnesota Mining And Manufacturing Company | Overhead projector with catadioptric fresnel lens |
| WO1995001587A1 (en) * | 1993-06-29 | 1995-01-12 | Minnesota Mining And Manufacturing Company | Overhead projector with achromatic fresnel lens |
| US5510861A (en) * | 1993-05-11 | 1996-04-23 | Proxima Corporation | Compact projector and method of using same |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2507515A1 (en) * | 1975-02-21 | 1976-09-02 | Klaus W Reiser & Co | Overhead projector for transparent writing support sheets - has internal reflector mirror and fresnel lens system |
-
1978
- 1978-10-31 JP JP13395978A patent/JPS5560934A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2507515A1 (en) * | 1975-02-21 | 1976-09-02 | Klaus W Reiser & Co | Overhead projector for transparent writing support sheets - has internal reflector mirror and fresnel lens system |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0304800B1 (en) * | 1987-08-24 | 1993-04-14 | ProCent Patent- und Verwaltungs AG | Overhead projector |
| US5296882A (en) * | 1992-12-21 | 1994-03-22 | Minnesota Mining And Manufacturing Company | Overhead projector with catadioptric fresnel lens |
| US5510861A (en) * | 1993-05-11 | 1996-04-23 | Proxima Corporation | Compact projector and method of using same |
| WO1995001587A1 (en) * | 1993-06-29 | 1995-01-12 | Minnesota Mining And Manufacturing Company | Overhead projector with achromatic fresnel lens |
| EP0706676A1 (en) * | 1993-06-29 | 1996-04-17 | Minnesota Mining & Mfg | Overhead projector with achromatic fresnel lens |
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