Light-emitting diode display apparatus with low electromagnetic display

• US 20040090403A1
• Filed: 11/08/2002
• Published: 05/13/2004
• Est. Priority Date: 11/08/2002
• Status: Abandoned Application

• Current Assignee: Dynascan Technology Corporation (Dynascan Technology)
• Original Assignee: Dynascan Technology Corporation (Dynascan Technology)
• Inventors: Huang, Ying-Chiun
• Application Number:
  US10/290,539
• Publication Number:
  US 20040090403A1
• Time in Patent Office: Days
• US Class Current: 345/82
• CPC Class Codes: H05B 45/48 having LEDs organised in strings and incorporating parallel shunting devices
• CPC Class Codes: H05B 45/54 in a series array of LEDs
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Abstract

A light-emitting diode display apparatus includes a diode string of a plurality of light-emitting diodes connected in series, a plurality of switch components each connected across a respective one of the light-emitting diodes, a voltage source that provides a working voltage to the diode string, and a current source that ensures flow of a constant current through assembly of the diode string and the switch components. Each switch component is independently controllable so as to operate in a selected one of an opened state, where the switch component permits current flow through the respective light-emitting diode, and a closed state, where the switch component prevents current flow through the respective light-emitting diode.

Claims

1. Alight-emitting diode display apparatus comprising:

a diode string including a plurality of light-emitting diodes connected in series;

a plurality of switch components, each of which is connected across a respective one of said light-emitting diodes and is independently controllable so as to operate in a selected one of an opened state, where said switch component permits current flow through the respective one of said light-emitting diodes, and a closed state, where said switch component prevents current flow through the respective one of said light-emitting diodes;

a voltage source coupled to said diode string and operable so as to provide a working voltage to said diode string; and

a current source coupled to said diode string and operable so as to ensure flow of a constant current through assembly of said diode string and said switch components.

2. The light-emitting diode display apparatus as claimed in claim 1, wherein said voltage source and said current source are coupled to opposite ends of said diode string.

3. The light-emitting diode display apparatus as claimed in claim 1, wherein each of said switch components is an electronic switch.

4. The light-emitting diode display apparatus as claimed in claim 1, wherein each of said switch components is a transistor.

5. The light-emitting diode display apparatus as claimed in claim 4, wherein said transistor is a field-effect transistor.

6. The light-emitting diode display apparatus as claimed in claim 1, further comprising a controller coupled to said switch components for controlling each of said switch components to operate in the selected one of the opened and closed states.