Flexible heating elements with patterned heating zones for heating of contoured objects powered by dual AC and DC voltage sources without transformer

• US 6,847,018 B2
• Filed: 02/25/2003
• Issued: 01/25/2005
• Est. Priority Date: 02/26/2002
• Status: Active Grant

• Current Assignee: Chon Meng Wong
• Original Assignee: Chon Meng Wong
• Inventors: Wong, Chon Meng
• Primary Examiner(s): Evans, Robin O.
• Assistant Examiner(s): Fastovsky, Leonid M
• Application Number:
  US10/373,421
• Publication Number:
  US 20030183620A1
• Time in Patent Office: 700 Days
• Field of Search: 219/505, 219/507, 219/541, 219/549, 219/475, 219/481, 219/488, 219/219, 338/308, 338/309, 307/72
• US Class Current: 219/549
• CPC Class Codes: H05B 2203/013 Heaters using resistive films or coatings
• CPC Class Codes: H05B 2203/028 Heaters specially adapted for trays or plates to keep food or liquids hot
• CPC Class Codes: H05B 2203/029 Heaters specially adapted for seat warmers
• CPC Class Codes: H05B 3/34 flexible, e.g. heating nets or webs

Abstract

A heating element made from flexible circuit technology with a single contiguous heating zone for uniform heating or multiple temperature heating zones is described. These flexible heating elements can conform to three dimensional object surfaces with irregular shape. The heating element'"'"'s overall flexibility and its thickness (in the region of 10 mils) allow for heating many object shapes in an efficient, compact and light-weight manner. Each thermal sensor or thermostat is used to regulate each heating zone and provide a unique temperature setting. A thermostat can be mounted directly on an object'"'"'s metallic surface. In addition, using diodes connected to the flexible heating element is described here to allow the use of two or multiple voltage sources. The technique permits one heating element to be powered from either AC or DC sources with comparable heating characteristics from both. The technique also eliminates the use of a transformer, which makes the heating solution simple and particularly compact and lightweight.

Claims

1. A heating apparatus capable of operation under either direct or alternation current comprising:

a heating element;

a first set of electrical contacts connected to said heating element; and

a second set of electrical contacts, each of said second set of electrical contacts connected via diodes to at least two locations on the heating element;

wherein the first set of electrical contacts are configured to receive alternating electrical current to heat the heating element to a first regulatable temperature and the second set of electrical contacts are configured to recieve direct electrical current to heat the heating element to a second regulatable temperature.

2. The apparatus of claim 1 wherein said first regulatable temperature is substantially the same as the second regulatable temperature.

3. The apparatus of claim 1 further comprising:

at least one thermally conductive film configured to provide an isothermal zone.

4. The apparatus of claim 1 wherein said at least one heating element comprises one of additive technology and subtractive technology.

5. A method of heating an electrical heating element using either direct or alternating current comprising:

providing a heating element;

selectively supplying either alternating electrical current to the heating element to heat the heating element to a first regulatable temperature, or delivering direct current via diodes to at least two different portions of the element to heat said heating element to a second regulatable temperature.

6. The method of claim 5 wherein the first regulatable temperature is substantially the same as the second regulatable temperature.

7. The method of claim 5 further comprising:

supplying at least one thermally conductive film configured to provide an isothermal zone.

8. A method of claim 5 wherein said heating element comprises one of additive technology and subtractive technology.