FR812965A - - Google Patents
Info
- Publication number
- FR812965A FR812965A FR812965DA FR812965A FR 812965 A FR812965 A FR 812965A FR 812965D A FR812965D A FR 812965DA FR 812965 A FR812965 A FR 812965A
- Authority
- FR
- France
- 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
- G03B21/54—Accessories
- G03B21/56—Projection screens
- G03B21/565—Screens allowing free passage of sound
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
Publications (1)
| Publication Number | Publication Date |
|---|---|
| FR812965A true FR812965A (en) | 1937-05-25 |
Family
ID=1553348
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| FR812965D Expired FR812965A (en) |
Country Status (1)
| Country | Link |
|---|---|
| FR (1) | FR812965A (en) |
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0
- FR FR812965D patent/FR812965A/fr not_active Expired