GB1483300A - Projectors - Google Patents
ProjectorsInfo
- Publication number
- GB1483300A GB1483300A GB5230675A GB5230675A GB1483300A GB 1483300 A GB1483300 A GB 1483300A GB 5230675 A GB5230675 A GB 5230675A GB 5230675 A GB5230675 A GB 5230675A GB 1483300 A GB1483300 A GB 1483300A
- Authority
- GB
- United Kingdom
- Prior art keywords
- lamp
- reflects
- projectors
- ritzerfeld
- disked
- 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.)
- Expired
Links
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
- G03B21/00—Projectors or projection-type viewers; Accessories therefor
- G03B21/132—Overhead projectors, i.e. capable of projecting hand-writing or drawing during action
-
- 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
- G03B21/00—Projectors or projection-type viewers; Accessories therefor
- G03B21/14—Details
- G03B21/20—Lamp housings
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Projection Apparatus (AREA)
Abstract
1483300 Projectors G RITZERFELD 22 Dec 1975 [3 Feb 1975 9 April 1975] 52306/75 Heading G2A In a projector comprising an optical projection system 10, a housing therebelow has a platen 3, a Fresnel condenser lens 4 and within it a projection lamp 6 below which is a reflector 7 with a disked reflecting surface, the central region of which has lower reflective power than the outer margin, or reflects non-convergent rays. There may be a heat filter 8 over the lamp 6. In the central part of the glass or metal mirror 11 is an insert, fixed adhesively or mechanically, which reflects a reduced amount of light to compensate for greater brightness of the image at its outer margins, and to reduce the running temperature of lamp 6. The surface may be conical, apex upward, or plane, or convex. It may be a matt aluminum surface, or formed of a coating of one or more of TiO 2 , Al 2 O 3 , MgO, ZnO or CaCO 3 in an inorganic binder e.g. waterglass.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19752505316 DE2505316A1 (en) | 1975-02-03 | 1975-02-03 | Optical projector with fresnel lens and internal light source - has concave mirror with less reflective central zone |
| DE19752515387 DE2515387A1 (en) | 1975-04-09 | 1975-04-09 | Optical projector with fresnel lens and internal light source - has concave mirror with less reflective central zone |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1483300A true GB1483300A (en) | 1977-08-17 |
Family
ID=25768471
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB5230675A Expired GB1483300A (en) | 1975-02-03 | 1975-12-22 | Projectors |
Country Status (3)
| Country | Link |
|---|---|
| DK (1) | DK542175A (en) |
| FR (1) | FR2299663A1 (en) |
| GB (1) | GB1483300A (en) |
-
1975
- 1975-12-02 DK DK542175A patent/DK542175A/en not_active Application Discontinuation
- 1975-12-12 FR FR7538101A patent/FR2299663A1/en active Granted
- 1975-12-22 GB GB5230675A patent/GB1483300A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| FR2299663A1 (en) | 1976-08-27 |
| FR2299663B3 (en) | 1979-10-05 |
| DK542175A (en) | 1976-08-04 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PS | Patent sealed | ||
| 732 | Registration of transactions, instruments or events in the register (sect. 32/1977) | ||
| PCNP | Patent ceased through non-payment of renewal fee |