Invention Grant
- Patent Title: Frustrated total internal reflection and capacitive sensing
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Application No.: US13631226Application Date: 2012-09-28
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Publication No.: US09891759B2Publication Date: 2018-02-13
- Inventor: Martin P. Grunthaner , Peter W. Richards , Romain A. Teil , Steven P. Hotelling
- Applicant: Apple Inc.
- Applicant Address: US CA Cupertino
- Assignee: Apple Inc.
- Current Assignee: Apple Inc.
- Current Assignee Address: US CA Cupertino
- Agency: Brownstein Hyatt Farber Schreck, LLP
- Main IPC: G06F3/044
- IPC: G06F3/044 ; G06F3/041 ; G06F3/042

Abstract:
Detecting force and touch using FTIR and capacitive location. FTIR determines applied force by the user's finger within infrared transmit lines on a touch device. A pattern of such lines determine optical coupling with the touch device. Capacitive sensing can determine (A) where the finger actually touches, so the touch device more accurately infers applied force; (B) whether finger touches shadow each other; (C) as a baseline for applied force; or (D) whether attenuated reflection is due to a current optical coupling, or is due to an earlier optical coupling, such as a smudge on the cover glass. If there is attenuated reflection without actual touching, the touch device can reset a baseline for applied force for the area in which that smudge remains. Infrared transmitters and receivers are positioned where they are not visible to a user, such as below a frame or mask for the cover glass.
Public/Granted literature
- US20140092052A1 Frustrated Total Internal Reflection and Capacitive Sensing Public/Granted day:2014-04-03
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