GB666222A - Improvements in or relating to optical lenses - Google Patents
Improvements in or relating to optical lensesInfo
- Publication number
- GB666222A GB666222A GB2041748A GB2041748A GB666222A GB 666222 A GB666222 A GB 666222A GB 2041748 A GB2041748 A GB 2041748A GB 2041748 A GB2041748 A GB 2041748A GB 666222 A GB666222 A GB 666222A
- Authority
- GB
- United Kingdom
- Prior art keywords
- elements
- lens
- screen
- face
- angles
- 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
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B3/00—Simple or compound lenses
- G02B3/02—Simple or compound lenses with non-spherical faces
- G02B3/08—Simple or compound lenses with non-spherical faces with discontinuous faces, e.g. Fresnel lens
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Overhead Projectors And Projection Screens (AREA)
Abstract
666,222. Lenses; projection screens. ELECTRIC & MUSICAL INDUSTRIES, Ltd. July 30, 1949 [July 31, 1948], No. 20417/48. Class 97 (i). Rectilinear prismatic elements are formed on both sides of a light-transmitting sheet, the elements on one side being at right-angles to those on the other, the angles of the elements increasing towards the perimeter of the sheet so as to form a Fresnel lens. The lens may be associated with a projection screen comprising a light-transmitting sheet having parallel cylindrical lenses on one surface and other parallel cylindrical lenses on the other surface at right angles to those on the first. Fig. 1 shows a cross-section, in one direction, of a combination of lens and screen, Fig. 2 being a section in a perpendicular direction. The screen 1 has semi-cylindrical elements 2 on one face and arcuate cylindrical elements 3 on the other face which may be silvered if a reflecting screen is required. The lens 6 has prismatic elements 7, on one face, of the same pitch as the screen elements 2. Similar prismatic elements 8 on the opposite face of the lens correspond to the screen elements 3. The centre of the lens may be left plane.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB2041748A GB666222A (en) | 1948-07-31 | 1948-07-31 | Improvements in or relating to optical lenses |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB2041748A GB666222A (en) | 1948-07-31 | 1948-07-31 | Improvements in or relating to optical lenses |
Publications (1)
Publication Number | Publication Date |
---|---|
GB666222A true GB666222A (en) | 1952-02-06 |
Family
ID=10145604
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB2041748A Expired GB666222A (en) | 1948-07-31 | 1948-07-31 | Improvements in or relating to optical lenses |
Country Status (1)
Country | Link |
---|---|
GB (1) | GB666222A (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3580661A (en) * | 1969-04-10 | 1971-05-25 | Bell & Howell Co | Rear projection viewing screen for close viewing |
US3598470A (en) * | 1969-11-05 | 1971-08-10 | Prismalite Inc | Projection screen and system |
-
1948
- 1948-07-31 GB GB2041748A patent/GB666222A/en not_active Expired
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3580661A (en) * | 1969-04-10 | 1971-05-25 | Bell & Howell Co | Rear projection viewing screen for close viewing |
US3598470A (en) * | 1969-11-05 | 1971-08-10 | Prismalite Inc | Projection screen and system |
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