Infrared optical system, imaging optical device, and digital appliance
US10578841B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | May 20, 2016 |
| Grant date | Mar 3, 2020 |
| Priority date | — |
| Expiry date | Apr 10, 2037 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N23/667
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
This infrared optical system using the wavelength range of 3 to 5 μm comprises, in the order from an object side, a first lens having a negative power and formed with a convex meniscus toward an object, a second lens that is convex on both sides, and a cold aperture. A bandpass filter is provided between the second lens and the image surface. The first and second lenses are configured with silicon or germanium with each provided with an aspheric surface at least on one side. The infrared optical system satisfies the conditional expressions: 0.1 μm<λ2−λ1<1 μm, 3 μm<λ1<5 μm, and 3 μm<λ2<5 μm. (Where λ1 and λ2 respectively represent a wavelength near the shorter wavelengths and a wavelength near the longer wavelengths in a half width of the transmission wavelength region of the bandpass filter).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.