US 11,054,734 B2
Optical element and projection apparatus
Chen-Wei Fan, Hsin-Chu (TW); and Ming-Tsung Weng, Hsin-Chu (TW)
Assigned to Coretronic Corporation, Hsin-Chu (TW)
Filed by Coretronic Corporation, Hsin-Chu (TW)
Filed on May 21, 2020, as Appl. No. 16/879,762.
Claims priority of application No. 201910437492.3 (CN), filed on May 24, 2019.
Prior Publication US 2020/0371417 A1, Nov. 26, 2020
Int. Cl. G03B 21/20 (2006.01)
CPC G03B 21/208 (2013.01) [G03B 21/204 (2013.01)] 22 Claims
OG exemplary drawing
 
1. An optical element, wherein the optical element is disposed between a light homogenizing element and a converging lens, the optical element comprises at least two regions, and the at least two regions comprise a first region and a second region, wherein the first region and the second region respectively adjust focus positions of a first beam formed through the first region and a second beam formed through the second region to the same position, the first beam and the second beam have different wavelengths, and the first region and the second region meet at least one of the following conditions:
(1) a wavelength of the first beam is less than a wavelength of the second beam, and a thickness of the first region is greater than a thickness of the second region; and
(2) the wavelength of the first beam is less than the wavelength of the second beam, and a refractive index of the first region is greater than a refractive index of the second region.