Projection lens including four lenses of −+−+ refractive powers
US11966012B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 12, 2021 |
| Grant date | Apr 23, 2024 |
| Priority date | — |
| Expiry date | Jan 23, 2042 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B21/00
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A projection lens projecting an image beam provided by a light valve onto a screen is provided. The projection lens includes first to fourth lenses in order from a screen side to a display side along an optical axis. Each lens has a screen side surface facing the screen side and allowing the image beam to pass, and a display side surface facing the display side and allowing the image beam to pass. The first and third lenses have a negative refractive power, and the second and fourth lenses have a positive refractive power. The projection lens satisfies 2<TTL/f<5. TTL is a distance from the screen side surface of the first lens to the display side surface of the fourth lens on the optical axis. f is an effective focal length of the projection lens. The projection lens covers a wide range of operating temperatures while being lightweight.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.