Planar heating device for a mirror and method of producing the same

• US 5,938,957 A
• Filed: 08/06/1997
• Issued: 08/17/1999
• Est. Priority Date: 08/21/1996
• Status: Expired due to Fees

• Current Assignee: Tokyo Cosmos Electric Co., Ltd.
• Original Assignee: Tokyo Cosmos Electric Co., Ltd.
• Inventors: Sakai, Nobuhiro, Tanahashi, Kazuyuki, Okano, Yoshitaka
• Primary Examiner(s): Walberg, Teresa
• Assistant Examiner(s): ROBINSON, DANIEL LEON
• Application Number:
  US08/908,666
• Time in Patent Office: 741 Days
• Field of Search: 219/219, 219/203
• US Class Current: 219/219
• CPC Class Codes: B60R 1/0602 comprising means for cleaning or deicing
• CPC Class Codes: H05B 3/845 specially adapted for reflecting surfaces, e.g. bathroom - or rearview mirrors

Abstract

A planar heating device for a mirror. The device comprises a glass film 18 formed on a metallic chrome film 16b on the back side of the mirror; a group of electrodes formed on the glass film, the group including main electrodes 3, 4, power terminal lead electrodes 5, 6 and sub-electrodes 7, 8; a resistance film 9 formed so as to cover the sub-electrodes; an electrically insulating film 20 formed on the resistance film 9 and the group of electrodes; and power terminals 11, 12 or power lead lines soldered to the respective power terminal lead electrodes 5, 6. The glass film 18 is formed directly on the back side of the mirror by screen printing or a spray process. The group of electrodes and the resistance film 9 are formed directly on the back side of the mirror by screen printing. Silver electrically conductive ink having inorganic glass as binder is used as a material for the group of electrodes. The glass film 18, the group of electrodes and the resistance film 9 may be printed in advance on a transfer paper sheet, followed by being transferred onto the back side of the mirror by a water transfer process.

Claims

1. A planar heating device in combination with a mirror having a front side and a back side, said planar heating device comprising:

a glass film formed on a metallic chrome film formed on the back side of the mirror;

a group of electrodes formed on said glass film, said electrodes being made of a material containing inorganic glass as a binder, said group of electrodes including a pair of opposed main electrodes, a pair of power terminal lead electrodes extending from corresponding main electrodes, and comb-like sub-electrodes extending from the corresponding main electrodes and power terminal lead electrodes so as to interdigitate one another;

a resistance film formed on said glass film so as to cover the sub-electrodes;

an electrically insulating film formed on said glass film over said resistance film; and

a pair of power terminals or power lead lines connected by soldering to the respective power terminal lead electrodes.

2. A method of producing a planar heating device in combination with a mirror having a front side and a back side, said method comprising the steps of:

(a) forming a glass film on a metallic chrome film formed on the back side of the mirror;

(b) forming a group of electrodes on said glass film from a material containing inorganic glass as a binder, said group being formed to include a pair of opposed main electrodes, a pair of power terminal lead electrodes extending from corresponding main electrodes, and comb-like sub-electrodes extending from the corresponding main electrodes and power terminal lead electrodes so as to interdigitate with each other;

(c) forming a resistance film on said glass film so as to cover the sub-electrodes;

(d) forming an electrically insulating film on said resistance film and said group of electrodes excluding said terminal lead electrodes and power terminal connections of said power terminal lead electrodes; and

(e) soldering a pair of power terminals or power lead lines to the power terminal connections of the respective power terminal lead electrodes.