Design and Fabrication of an ultra-thin under-display fingerprint sensor

Wei Jei Peng, Jhe Syuan Lin, Yuan Chieh Cheng, Ming Fu Chen, Wen Shing Sun

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review


Recently, the phones with high screen-to-body ratio are popular in the market, and it leads to the demand of in-display fingerprint recognition. The optical fingerprint sensor is based on frustrated total internal reflection (FTIR), and the camera type independent on the panel process is cost-effective and with high yield rate. To meet the volume constraint of the smart phone, a miniaturized compact lens is designed. For maximizing the sensing area in the limited space, the field of view can reach 128°. To increase the accuracy and speed of the recognition, the design has extremely small distortion and low f-number. Mostly importantly, the resolution should be sufficient for the fingerprint extraction algorithm. To achieve the specifications, the lens is designed with three aspheric plastic lenses using injection molding. In this paper, the procedure of optical design, mechanical design, lens fabrication and assembly of the prototype is presented. Finally, the prototype is employed for fingerprint identification.

Original languageEnglish
Title of host publicationOptical Design and Testing X
EditorsYongtian Wang, Tina E. Kidger, Osamu Matoba, Rengmao Wu
ISBN (Electronic)9781510639119
StatePublished - 2020
EventOptical Design and Testing X 2020 - Virtual, Online, China
Duration: 11 Oct 202016 Oct 2020

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferenceOptical Design and Testing X 2020
CityVirtual, Online


  • Fingerprint identification
  • Frustrated total internal reflection
  • In-display fingerprint recognition
  • Injection molding
  • Screen-to-body ratio
  • Ultra-thin fingerprint sensor


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