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Control Method of Dual Color Light Emitting Diode

IP.com Disclosure Number: IPCOM000116366D
Original Publication Date: 1995-Sep-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 27K

Publishing Venue

IBM

Related People

Narita, I: AUTHOR

Abstract

Disclosed is a method for controlling dual color Light Emitting Diode (LED). A dual color LED is assumed which is composed of a red LED and a green LED. With the conventional control method, the LED can only emit the red, the green and yellow which is made by the red and the green. With this invention, the LED can emit any three colors between red and green.

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Control Method of Dual Color Light Emitting Diode

      Disclosed is a method for controlling dual color Light Emitting
Diode (LED).  A dual color LED is assumed which is composed of a red
LED and a green LED.  With the conventional control method, the LED
can only emit the red, the green and yellow which is made by the red
and the green.  With this invention, the LED can emit any three
colors between red and green.

      The Figure shows the circuit implementing this invention.  In
the Figure, while a transistor TR1 becomes ON, the current flows
through a resister R1 and a resister R4.  So, the red LED and the
green LED light with the current.  While a transistor TR2 becomes ON,
the current flows through a resister R2 and a resister R3.  So, the
red LED and the green LED light with the current.  With the selecting
of the resisters' value, any three colors between red and green can
be lit with the combination of TR1_ON signal and TR2_ON signal.