Optical encoder with sinusoidal photodetector output signal

US7399956B2 · kind B2 · utility

Assignee

• Avago Technologies ECBU IP Pte. Ltd. · SG

Inventors

• Weng Fei Wong · Bukit Mertajam, MY
• Chee Foo Lum · Bukit Mertajam, MY
• Siang Leong Foo · Bukit Mertajam, MY
• Song Wah Ooi · Bukit Mertajam, MY
• Keen-Hun Leong · Bukit Mertajam, MY
• Yik Foong Soo · Bayan Lepas, MY
• Sai Hong Hung · Bukit Mertajam, MY
• Gin Ghee Tan · Bayan Lepas, MY

Key dates

• Filing date: Nov 28, 2005
• Grant date: Jul 15, 2008
• Expiry date: Nov 28, 2025

Classification

• Technology area (CPC G): Physics
• CPC primary: G01D5/34707
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

An optical encoder includes an optical encoder pattern of alternating light elements and dark elements, and an optical unit, including an optical emitter providing light to the encoder pattern, and an optical sensor including a photo-detector receiving the light from the optical encoder pattern and in response thereto outputting a sinusoidal signal indicating relative movement between the optical sensor and the encoder pattern. In one embodiment, the photo-detector has a diamond shape, a modified-diamond shape, or an hourglass shape. In another embodiment, at least one of the light elements and the dark elements of the optical encoder pattern has a diamond shape, a modified-diamond shape, or an hourglass shape.