公开(公告)号：US20210080245A1

公开(公告)日：2021-03-18

申请号：US16569586

申请日：2019-09-12

Applicant: Apple Inc.

Inventor： Mehmet MUTLU ,  Michael K. BROWN ,  Wesley S. SMITH ,  Orit A. SHAMIR ,  Richard T. CHEN ,  Mark T. WINKLER ,  Miaolei YAN ,  Richard YEH

IPC: G01B9/02 ,  H01S5/183

Abstract: Aspects of the subject technology relate to an apparatus for self-mixing particulate-matter sensing using a vertical-cavity surface-emitting laser (VCSEL) with extrinsic photodiodes. The apparatus includes a dual-emitting light source disposed on a first chip and to generate a first light beam and a second light beam. The first light beam illuminates a particulate matter (PM), and a light detector extrinsic to the first chip measures the second light beam and variations of the second light beam and generates a self-mixing signal. The variations of the second light beam are caused by a back-scattered light resulting from back-scattering of the first light beam from the PM. The light detector is coupled to the dual-emitting light source. The direction of the second light beam is opposite to the direction of the first light beam, and the second light beam is directed to a sensitive area of the light detector.