Noise reduction in LED sensing circuit for electronic display

US10460642B2 · kind B2 · utility

Assignee

• Apple Inc. · US

Inventors

• Hung Sheng Lin · San Jose, US
• Jiayi Jin · Redwood City, US
• Wei H. Yao · Palo Alto, US
• Hyunwoo Nho · Palo Alto, US
• Guangmao Xing · San Jose, US
• Weijun Yao · Saratoga, US
• Xiaofeng Wang · Anshan City, CN
• Yafei Bi · Los Altos Hills, US
• Haifeng Li · Zhejiang, CN

Key dates

• Filing date: Jun 30, 2016
• Grant date: Oct 29, 2019
• Expiry date: Oct 17, 2037

Classification

• Technology area (CPC G): Physics
• CPC primary: G09G2320/0693
• WIPO field: Audio-visual technology
• WIPO sector: Electrical engineering

Abstract

Systems, methods, and devices are provided to reduce noise present in sensing circuits used for calibrating light emitting diodes (e.g., organic light emitting diodes) in electronic display devices. Such a system may include a display that renders image data using self-emissive pixels. Values on the pixels may be sensed using a current source that outputs a current and a comparator that receives the current. The comparator changes states when a voltage signal output by the capacitor crosses a first threshold voltage or a second threshold voltage. A controller receives a first time when the comparator component changes states based on the voltage signal, receives a second time when the comparator component changes states based on the voltage signal, determines a current value based on the first time and the second time, and calibrates a pixel based on the current value.