Title:
SELF-TEMPERATURE FOCUS COMPENSATION DEVICE
Document Type and Number:
Japanese Patent JP2021157177
Kind Code:
A
Abstract:
To provide a self-temperature focus compensation device which is adapted to cooperate with a lens group and includes at least one Fresnel lens group.SOLUTION: Each Fresnel lens group has zero focal power at a specific temperature and is a cemented lens. Each Fresnel lens group includes a first Fresnel lens and a second Fresnel lens. The first Fresnel lens has positive focal power. The second Fresnel lens has negative focal power. A sum of a change in focal power of at least one Fresnel lens group due to a temperature change and a change in focal power of the lens group due to the temperature change is zero or close to zero in a certain temperature range.SELECTED DRAWING: Figure 1
Inventors:
HUANG SHI-HWA
Application Number:
JP2021049787A
Publication Date:
October 07, 2021
Filing Date:
March 24, 2021
Export Citation:
Assignee:
HUANG SHI HWA
International Classes:
G02B13/00; G02B3/08
Domestic Patent References:
| JP2002522809A | 2002-07-23 | |||
| JP2009047732A | 2009-03-05 | |||
| JP2015521148A | 2015-07-27 |
Foreign References:
| EP2687889A1 | 2014-01-22 |
Attorney, Agent or Firm:
Kiuchi Mitsuharu
Koichi Okuma
Katagiri Sadanori
Kanako Kiuchi
Koichi Okuma
Katagiri Sadanori
Kanako Kiuchi