GB1474847A - Projection lens system - Google Patents
Projection lens systemInfo
- Publication number
- GB1474847A GB1474847A GB1726775A GB1726775A GB1474847A GB 1474847 A GB1474847 A GB 1474847A GB 1726775 A GB1726775 A GB 1726775A GB 1726775 A GB1726775 A GB 1726775A GB 1474847 A GB1474847 A GB 1474847A
- Authority
- GB
- United Kingdom
- Prior art keywords
- lens
- focal length
- elements
- main
- main 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.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B9/00—Optical objectives characterised both by the number of the components and their arrangements according to their sign, i.e. + or -
- G02B9/12—Optical objectives characterised both by the number of the components and their arrangements according to their sign, i.e. + or - having three components only
- G02B9/14—Optical objectives characterised both by the number of the components and their arrangements according to their sign, i.e. + or - having three components only arranged + - +
- G02B9/16—Optical objectives characterised both by the number of the components and their arrangements according to their sign, i.e. + or - having three components only arranged + - + all the components being simple
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B13/00—Optical objectives specially designed for the purposes specified below
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B9/00—Optical objectives characterised both by the number of the components and their arrangements according to their sign, i.e. + or -
- G02B9/34—Optical objectives characterised both by the number of the components and their arrangements according to their sign, i.e. + or - having four components only
-
- 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)
- Lenses (AREA)
- Medicines Containing Plant Substances (AREA)
- External Artificial Organs (AREA)
- Acyclic And Carbocyclic Compounds In Medicinal Compositions (AREA)
Abstract
1474847 Projection lens systems LINDACO Ltd 25 April 1975 [29 May 1974] 17267/75 Heading G2J In a projection system the lens system comprises a main positive lens, which may be composed of a plurality of elements, and a positive field lens, which may also be composed of a plurality of elements, the field lens being disposed between the object and the main lens, and the main lens having a focal length between 1À2 and 2À5 times the focal length of the system, the system focal length being greater than 400 mm. and having a relative aperture greater than 1:3À5. In a preferred form the main lens is a triplet and the outermost elements have a refractive index less than 1À53, while the central element has a refractive index less than 1À65. In a system of 600 mm. focal length the main lens is conveniently of 900 mm. focal length. The field lens may be of one or two elements, may be a Fresnel lens, and may be of plastics material. It is preferably comparable in size with the object and located mid way between the object and the main lens. It may be axially moveable for focussing. The invention is particularly useful for overhead projectors especially with diffusely radiating objects, e.g. Pictures, T.V. screens etc.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE7407134A SE382262B (en) | 1974-05-29 | 1974-05-29 | PROJECTION OPTICS. |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1474847A true GB1474847A (en) | 1977-05-25 |
Family
ID=20321270
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB1726775A Expired GB1474847A (en) | 1974-05-29 | 1975-04-25 | Projection lens system |
Country Status (21)
| Country | Link |
|---|---|
| JP (1) | JPS513228A (en) |
| AT (1) | AT351828B (en) |
| BE (1) | BE829494A (en) |
| BR (1) | BR7503348A (en) |
| CA (1) | CA1050314A (en) |
| CH (1) | CH585910A5 (en) |
| CS (1) | CS192543B2 (en) |
| DD (1) | DD120942A5 (en) |
| DE (1) | DE2519991A1 (en) |
| DK (1) | DK238075A (en) |
| ES (1) | ES436963A1 (en) |
| FI (1) | FI751515A (en) |
| FR (1) | FR2273290B1 (en) |
| GB (1) | GB1474847A (en) |
| HU (1) | HU175781B (en) |
| IT (1) | IT1037780B (en) |
| NL (1) | NL7506296A (en) |
| NO (1) | NO139872C (en) |
| PL (1) | PL104910B1 (en) |
| SE (1) | SE382262B (en) |
| SU (1) | SU625640A3 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4311366A (en) * | 1978-03-01 | 1982-01-19 | J. H. Dallmeyer Limited | Image focusing system |
| US4380374A (en) * | 1981-04-16 | 1983-04-19 | Minnesota Mining & Manufacturing Company | Variable focal length projection lens for use on overhead projectors |
| JP2691566B2 (en) * | 1988-06-14 | 1997-12-17 | 旭光学工業株式会社 | Magnifying projection lens |
| JP2954217B2 (en) * | 1987-12-09 | 1999-09-27 | 株式会社日立製作所 | Projection lens |
-
1974
- 1974-05-29 SE SE7407134A patent/SE382262B/en not_active IP Right Cessation
-
1975
- 1975-04-24 NO NO751480A patent/NO139872C/en unknown
- 1975-04-25 ES ES436963A patent/ES436963A1/en not_active Expired
- 1975-04-25 GB GB1726775A patent/GB1474847A/en not_active Expired
- 1975-04-30 IT IT22916/75A patent/IT1037780B/en active
- 1975-05-01 CA CA226,075A patent/CA1050314A/en not_active Expired
- 1975-05-05 DE DE19752519991 patent/DE2519991A1/en not_active Withdrawn
- 1975-05-15 FR FR7515205A patent/FR2273290B1/fr not_active Expired
- 1975-05-26 AT AT398475A patent/AT351828B/en not_active IP Right Cessation
- 1975-05-26 BE BE156716A patent/BE829494A/en unknown
- 1975-05-26 FI FI751515A patent/FI751515A/fi not_active Application Discontinuation
- 1975-05-26 SU SU752136683A patent/SU625640A3/en active
- 1975-05-27 CH CH679275A patent/CH585910A5/xx not_active IP Right Cessation
- 1975-05-27 HU HU75LI276A patent/HU175781B/en unknown
- 1975-05-27 DD DD186283A patent/DD120942A5/xx unknown
- 1975-05-27 BR BR4278/75A patent/BR7503348A/en unknown
- 1975-05-28 PL PL1975180786A patent/PL104910B1/en unknown
- 1975-05-28 JP JP50063946A patent/JPS513228A/ja active Pending
- 1975-05-28 NL NL7506296A patent/NL7506296A/en not_active Application Discontinuation
- 1975-05-28 CS CS753750A patent/CS192543B2/en unknown
- 1975-05-28 DK DK238075A patent/DK238075A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| BE829494A (en) | 1975-09-15 |
| SU625640A3 (en) | 1978-09-25 |
| NO139872B (en) | 1979-02-12 |
| IT1037780B (en) | 1979-11-20 |
| CH585910A5 (en) | 1977-03-15 |
| AT351828B (en) | 1979-08-10 |
| DK238075A (en) | 1975-11-30 |
| BR7503348A (en) | 1976-04-27 |
| ATA398475A (en) | 1979-01-15 |
| DE2519991A1 (en) | 1975-12-18 |
| SE7407134L (en) | 1975-12-01 |
| SE382262B (en) | 1976-01-19 |
| FI751515A (en) | 1975-11-30 |
| AU8129275A (en) | 1976-11-25 |
| JPS513228A (en) | 1976-01-12 |
| FR2273290B1 (en) | 1980-07-11 |
| CS192543B2 (en) | 1979-08-31 |
| FR2273290A1 (en) | 1975-12-26 |
| NO751480L (en) | 1975-12-02 |
| NO139872C (en) | 1979-05-23 |
| ES436963A1 (en) | 1976-12-01 |
| NL7506296A (en) | 1975-12-02 |
| HU175781B (en) | 1980-10-28 |
| PL104910B1 (en) | 1979-09-29 |
| DD120942A5 (en) | 1976-07-05 |
| CA1050314A (en) | 1979-03-13 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PS | Patent sealed [section 19, patents act 1949] | ||
| PCNP | Patent ceased through non-payment of renewal fee |