Light emitting diode fabricated with resistors for variable light intensity

• US 5,569,939 A
• Filed: 01/27/1995
• Issued: 10/29/1996
• Est. Priority Date: 12/18/1991
• Status: Expired due to Fees

• Current Assignee: Goldstar Jewellery LLC
• Original Assignee: Goldstar Jewellery LLC
• Inventors: Choi, Seong C.
• Primary Examiner(s): Crane, Sara W.
• Assistant Examiner(s): Wallace, Valencia Martin
• Application Number:
  US08/379,103
• Time in Patent Office: 641 Days
• Field of Search: 257/13, 257/81, 257/82, 257/84, 257/85, 257/86, 257/90, 257/94, 257/96, 257/97
• US Class Current: 257/94
• CPC Class Codes: H01L 27/15 including semiconductor components having potential barriers, specially adapted for light emission

Abstract

A light emitting diode (LED) and resistors for varying the light intensity of the LED are formed on a single chip. Each of the LED portion and the resistor portion includes an active layer and a clad layer successively deposited on a substrate of the chip. The substrate may be doped with one of P-type dopant and N-type dopant and the clad layer with the other of P and Y-type dopants. A first and second electrodes are formed on an exposed surface of the substrate and the clad layer of the LED portion respectively. A plurality of resistor electrodes are formed on the clad layer of the resistor portion. It is preferable to have different spacing between the resistor electrodes to form variable resistances.

Claims

1. A variable light intensity light emitting diode comprising:

a substrate doped with at least one of P-type and N-type dopants, said substrate having a first side and second side which is opposite said first side;

a light emitting diode portion for emitting light having a first active layer formed over said first side of said substrate and a first clad layer formed on said first active layer, said first clad layer being doped with a different type of dopant from that of said substrate and having a first electrode formed on said clad layer, and a second electrode formed on one of said first and second sides of said substrate; and

a resistor portion separate from said light emitting diode portion for multistage limitations of current flow to said light emitting diode portion having a second active layer formed on one of said first and second sides of said substrate and a second clad layer doped with a different type of dopant from that of said substrate, and a plurality of resistor electrodes formed on said second clad layer.

2. The light emitting diode according to claim 1, wherein said plurality of resistor electrodes are positioned so that the distances between said resistor electrodes are different.

3. The light emitting diode according to claim 1, wherein said second electrode is formed on said second side.

4. The light emitting diode according to claim 1, wherein said substrate is a semi-insulating substrate.

5. The light emitting diode according to claim 1, further comprising an additional clad layer disposed between said substrate and said first active layer and between said substrate and said second active layer, each of said additional clad layers being doped with the same type of dopant as said substrate.

6. The light emitting diode according to claim 5, wherein said plurality of resistor electrodes are positioned so that the distance between said resistor electrodes are different.

7. The light emitting diode according to claim 5, wherein said second electrode is formed on said second side.

8. The light emitting diode according to claim 5, wherein said substrate is a semi-insulating substrate.

9. The light emitting diode according to claim 5, wherein said resistor portion and said light emitting diode portion are both formed on said first side and wherein portions of said additional clad layer is exposed by photoetching, said first electrode is formed on the exposed portion of said additional clad layer.

10. The light emitting diode according to claim 9, wherein said plurality of resistor electrodes are positioned so that the distance between said resistor electrodes are different respectively.

11. The light emitting diode according to claim 9, wherein said substrate is a semi-insulating substrate.