Light-emitting device using voltage switchable dielectric material

• US 7,825,491 B2
• Filed: 11/21/2006
• Issued: 11/02/2010
• Est. Priority Date: 11/22/2005
• Status: Expired due to Fees

• Current Assignee: Littelfuse Incorporated
• Original Assignee: Shocking Technologies, Inc.
• Inventors: Kosowsky, Lex
• Primary Examiner(s): Bryant; Kiesha R
• Assistant Examiner(s): Yang; Minchul
• Application Number:
  US11/562,289
• Publication Number:
  US 20070126018A1
• Time in Patent Office: 1,442 Days
• Field of Search: 257/50, 257/529, 257/530, 257/E23.147, 313/580, 338/21
• US Class Current: 257/530
• CPC Class Codes: H01L 25/167 comprising optoelectronic devices, e.g. LED, photodiodes
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 2924/12044 OLED
• CPC Class Codes: H05K 1/0257 Overvoltage protection
• CPC Class Codes: H05K 1/0259 Electrostatic discharge [ESD] protection
• CPC Class Codes: H05K 1/0373 containing additives, e.g. fillers H05K1/036 takes precedence
• CPC Class Codes: H05K 1/05 Insulated conductive substrates, e.g. insulated metal substrate
• CPC Class Codes: H05K 1/167 incorporating printed resistors
• CPC Class Codes: H05K 2201/0738 Use of voltage responsive materials, e.g. voltage switchable dielectric or varistor materials
• CPC Class Codes: H05K 2201/10106 Light emitting diode [LED]
• CPC Class Codes: H10K 50/805 Electrodes
• CPC Class Codes: H10K 50/88 Terminals, e.g. bond pads

Abstract

A voltage switchable dielectric material (VSD) material as part of a light-emitting component, including LEDs and OLEDs.

Claims

1. A light-emitting device comprising:

a semiconductor structure having semiconductive organic material, the semiconductor structure providing a component that is structured to emit light by carrying current between at least a first terminal and a second terminal;

an organic polymer composition comprising a combination of conductor and/or semiconductor particles, wherein the polymer composition is structured to have a characteristic of (i) being a dielectric in absence of a voltage that exceeds a characteristic voltage level of the composition, and (ii) with application of the voltage exceeding the characteristic voltage level, switching into a conductor for only a duration in which the voltage is present;

wherein the composition is positioned, relative to the component that emits light, to provide grounding for the component against any transient voltage that exceeds the characteristic voltage level of the composition.

2. The device of claim 1, wherein the component is a diode.

3. The device of claim 1, wherein the component is formed from a semiconductor material.

4. The device of claim 3, wherein the component includes a first lead extending from the first terminal, and a second lead extending from a second terminal, and wherein the composition is positioned between and in contact with the first lead and the second lead.

5. The device of claim 3, wherein the component is provided on a substrate, and wherein the composition is provided with the substrate.

6. The device of claim 5, wherein the material is provided on the substrate to underlie any one or more of (i) the component formed from the semiconductor material, (ii) the first terminal of the component, (iii) the second terminal of the component, (iv) a first lead of the first terminal, or (v) a second lead of the second terminal.

7. The device of claim 1, wherein the component is formed from an organic polymer.

8. The device of claim 1, wherein the composition is provided to contact any one or more of (i) the semiconductor material, (ii) the first terminal of the component, (iii) the second terminal of the component, (iv) a first lead extending from the first terminal, or (v) a second lead extending from the second terminal.

9. The device of claim 1, wherein the device has a characteristic breakdown voltage, corresponding to a minimum voltage value that, when applied to the component, causes the device to fail, and wherein the characteristic voltage value of the composition is less than the characteristic breakdown voltage.

10. A light-emitting device comprising:

a semiconductor component having semiconductive organic material and configured to emit light when a current is applied to the component;

a composition of organic polymer provided with the semiconductor component, the composition comprising a combination of conductor and/or semiconductor particles, and wherein the composition is structured to have a characteristic of (i) being a dielectric in absence of a voltage that exceeds a characteristic voltage level of the composition, and (ii) with application of the voltage exceeding the characteristic voltage level, switching into a conductor for only a duration in which the voltage is present;

wherein the composition is positioned to direct current away from the semiconductor when the composition is conductive.

11. The device of claim 10, wherein the semiconductor component is a diode.

12. The device of claim 10, wherein the device has a characteristic breakdown voltage that corresponds to a minimum voltage value that, when applied to the component, causes the device to fail, and wherein the characteristic voltage value of the composition is less than the characteristic breakdown voltage.

13. The device of claim 10, wherein the composition is applied on a substrate on which the semiconductor component is mounted.

14. The device of claim 13, wherein the composition is used to adhere the semiconductor component to the substrate.

15. The device of claim 10, wherein the semiconductor component includes a first terminal and a second terminal, and wherein the composition is in electrical contact with either or both of the first terminal and the second terminal.

16. The device of claim 15, wherein the composition extends between and contacts a first lead extending from the first terminal, and a second lead extending from the second terminal.

17. The device of claim 10, wherein the device further comprises a casing, and wherein the composition is provided with or as part of the casing.

18. A light-emitting device comprising:

a stack comprising a plurality of layers, the plurality of layers including an organic light emitter layer;

a voltage switchable material (VSD) formed from an organic polymer composition comprising a combination of conductor and/or semiconductor particles, wherein the polymer composition is coupled to the stack, wherein the VSD material is positioned to have a characteristic of (i) being a dielectric in absence of a voltage that exceeds a characteristic voltage level of the VSD material, and (ii) with application of the voltage exceeding the characteristic voltage level, switching into a conductor for only a duration in which the voltage is present;

wherein the VSD material is positioned to direct current away from the stack when in the VSD material is conductive.

19. The device of claim 18, wherein the stack includes an anode terminal and a cathode terminal on which a voltage differential is applied, and wherein the VSD material is provided in connection with one or both of the terminals.

20. The device of claim 19, wherein the cathode terminal is provided on a driver, and wherein the VSD material underlies the driver and directs current away from the stack when made conductive.