Thin-film heating element

• US 9,493,906 B2
• Filed: 11/11/2004
• Issued: 11/15/2016
• Est. Priority Date: 11/20/2003
• Status: Expired due to Fees

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips N.V.
• Inventors: Werkman, Pieter Johannes, Rethmeier, Roel
• Primary Examiner(s): STAPLETON, ERIC S
• Application Number:
  US10/579,647
• Publication Number:
  US 20090114639A1
• Time in Patent Office: 4,387 Days
• Field of Search: 219/543, 219/444.1, 219/544, 219/546, 219/548, 219/552, 219/553, 428/1.51, 428 16- 162, 428/70, 428/447, 428/448, 428/450, 428/688, 428/689, 296/101, 296/11, 296/20
• US Class Current: 1/1
• CPC Class Codes: D06F 75/24 Arrangements of the heating means within the iron; Arrangements for distributing, conducting or storing the heat
• CPC Class Codes: H05B 3/262 the insulating base being an insulated metal plate
• CPC Class Codes: Y10T 29/49083 Heater type

Abstract

A heating element and a method of manufacturing the heating element including an aluminum substrate, an electrically insulating layer based on a sol-gel precursor, and an electrically resistive layer with a thickness smaller than 2 μm. The features of this heating element solve the problem of the crack formation due to a mismatch of thermal expansion coefficient of the aluminum substrate and the resistive layer. Also an electrical domestic appliance including the heating element.

Claims

1. A heating element, comprising an anodized aluminum substrate, an electrically insulating layer including a sol-gel precursor material and non-conductive particles having a flake-like shape, and a thin-film electrically resistive layer of a doped metal oxide including one of an aluminum-doped zinc oxide and a tin oxide doped with antimony with a thickness smaller than 2 μ

m, with the sol-gel precursor material of the electrically insulating layer positioned between the anodized aluminum substrate and the thin-film electrically resistive layer and in contact with the thin-film electrically resistive layer and the anodized aluminum substrate thereby insulating the anodized aluminum substrate from the thin-film electrically resistive layer.

2. The heating element as claimed in claim 1, wherein the sol-gel precursor material is a hybrid sol-gel material comprising an organosilane compound from a group of alkyl-alkoxysilanes.

3. The heating element as claimed in claim 1, wherein the sol-gel precursor material comprises methyl-trimethoxysilane or methyl-triethoxysilane.

4. The heating element as claimed in claim 1, wherein the heating element further comprises a conductive layer comprising one of Pl/Ag and a sol-gel/Ag paste in contact with the thin-film electrically resistive layer.

8. The heating element as claimed in claim 1, wherein the thin-film electrically resistive layer comprises a metal oxide including one of a tin oxide and indium-tin oxide (ITO).

10. The heating element as claimed in claim 1, wherein the sol-gel precursor material comprises silicon bonded to at least one non-hydrolysable organic group and 2 or 3 hydrolyzable organic groups.

11. The heating element as claimed in claim 1, wherein the sol-gel precursor material comprises colloidal silica particles.

12. The heating element as claimed in claim 1, wherein the non-conductive particles comprise a longest dimension of from 2 to 150 μ

m.

13. The heating element as claimed in claim 12, wherein the non-conductive particles comprise a longest dimension of from 5 to 60 μ

m.

14. The heating element as claimed in claim 1, wherein the non-conductive particles comprise less than a 15% volume of the electrically insulating layer.

15. The heating element as claimed in claim 14, wherein the non-conductive particles comprise from 4-10% volume of the electrically insulating layer.

16. The heating element as claimed in claim 1, wherein the non-conductive particles are present in the electrically insulating layer in colloidal form.

17. The heating element as claimed in claim 3, wherein the sol-gel precursor material further comprises hydroxyl-propylmethyl cellulose and butoxyethanol.

5. An electrical domestic appliance comprising a heating element comprising an anodized aluminum substrate, an electrically insulating layer including a sol-gel precursor material and non-conductive particles having a flake-like shape, and a thin-film electrically resistive layer of a doped metal oxide including one of an aluminum-doped zinc oxide and a tin oxide doped with antimony with a thickness smaller than 2 μ

m, with the sol-gel precursor material of the electrically insulating layer positioned between the anodized aluminum substrate and the thin-film electrically resistive layer and in contact with the thin-film electrically resistive layer and the anodized aluminum substrate thereby insulating the anodized aluminum substrate from the thin-film electrically resistive layer.

6. The electrical domestic appliance according to claim 5, wherein the electrical domestic appliance comprises one of a steam iron, a hair dryer, a hair styler, a steamer and a steam cleaner, a garment cleaner, a heated ironing board, a facial steamer, a kettle, a pressurized boiler for system irons and cleaners, a coffee maker, a deep-fat fryer, a rice cooker, a sterilizer, a hot plate, a hot-pot, a grill, a space heater, a waffle iron, a toaster, an oven, or a water flow heater.

7. A method of manufacturing a heating element, the method comprising acts of:

providing an anodized aluminum substrate;

applying an electrically insulating layer including a sol-gel precursor material and non-conductive particles having a flake-like shape on said anodized aluminum substrate by a sol-gel process; and

applying a thin-film resistive layer of a doped metal oxide including one of an aluminum-doped zinc oxide and a tin oxide doped with antimony having a thickness smaller than 2 μ

m directly on top of the electrically insulating layer thereby insulating the anodized aluminum substrate from the thin-film resistive layer, wherein the sol-gel precursor material of the electrically insulating layer is in contact with the thin-film electrically resistive layer and the anodized aluminum substrate.

9. The method as claimed in claim 7, wherein the act of applying the thin-film resistive layer to the electrically insulating layer comprises an act of performing one of magnetron sputtering, thermal spraying, and wet-chemical deposition techniques of the thin-film resistive layer.