Embedded electrical traces

• US 6,929,849 B2
• Filed: 05/21/2003
• Issued: 08/16/2005
• Est. Priority Date: 08/28/2001
• Status: Expired due to Fees

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Miller, Michael N., Jing, Naiyong, Koskenmaki, David C.
• Primary Examiner(s): LAM, CATHY FONG FONG
• Application Number:
  US10/442,396
• Publication Number:
  US 20030196830A1
• Time in Patent Office: 818 Days
• Field of Search: 174250-251, 428/209, 428/901
• US Class Current: 428/209
• CPC Class Codes: G02F 1/13439 characterised by their electrical, optical, physical properties; materials therefor; method of making
• CPC Class Codes: G02F 1/155 Electrodes
• CPC Class Codes: H05B 2203/017 Manufacturing methods or apparatus for heaters
• CPC Class Codes: H05B 3/286 the insulating material being an organic material, e.g. plastic
• CPC Class Codes: H05B 3/86 the heating conductors being embedded in the transparent or reflecting material H05B3/845 takes precedence
• CPC Class Codes: H05K 2201/0133 Elastomeric or compliant polymer elastomeric conductor H05K2201/0314
• CPC Class Codes: H05K 2201/09036 Recesses or grooves in insulating substrate recess in metallic substrate H05K2201/09745
• CPC Class Codes: H05K 2201/091 Locally and permanently deformed areas including dielectric material
• CPC Class Codes: H05K 2201/09827 Tapered, e.g. tapered hole, via or groove bevelled, chamferred or tapered edge H05K2201/09154
• CPC Class Codes: H05K 2203/0278 Flat pressure, e.g. for connecting terminals with anisotropic conductive adhesive
• CPC Class Codes: H05K 2203/1105 Heating or thermal processing not related to soldering, firing, curing or laminating, e.g. for shaping the substrate or during finish plating
• CPC Class Codes: H05K 3/102 by bonding of conductive powder, i.e. metallic powder H05K3/12 takes precedence
• CPC Class Codes: H05K 3/107 by filling grooves in the support with conductive material H05K3/045, H05K3/101, H05K3/1258 and H05K3/465 take precedence
• CPC Class Codes: H05K 3/1258 by using a substrate provided with a shape pattern, e.g. grooves, banks, resist pattern
• CPC Class Codes: Y10S 428/901 Printed circuit
• CPC Class Codes: Y10T 29/49128 Assembling formed circuit to base
• CPC Class Codes: Y10T 29/49155 Manufacturing circuit on or in base
• CPC Class Codes: Y10T 29/49165 by forming conductive walled aperture in base
• CPC Class Codes: Y10T 428/24917 including metal layer

Abstract

A method for making a fine electrically conductive grid embedded in a polymer substrate. The method includes the steps of providing a polymer substrate, forming a pattern of grooves in the substrate, filling the grooves with electrically conductive powder, and then applying heat and/or pressure to the substrate. The application of heat and/or pressure to the substrate causes the grooves to collapse inward against the conductive powder. Collapsing the grooves compacts the conductive powder within the groove, thereby establishing a continuously conductive grid line or circuit. The narrow grid lines that result allow more light to transmit through the substrate. The method allows grid lines to be made with higher aspect ratios (ratio of line depth to line width) than is possible by previous methods.

Claims

1. An electrically conductive sheet material comprising:

a polymer substrate;

a pattern of metal traces in channels of the substrate, the metal traces retained compressively by inwardly collapsed walls of the channels in the substrate.

2. The electrically conductive sheet material of claim 1, wherein the trace is less than 2 microns wide.

3. The electrically conductive sheet material of claim 1, wherein the trace has a ratio of depth to width of greater than 5.

4. The electrically conductive sheet material of claim 1, wherein the trace has a ratio of depth to width of greater than 10.

5. The electrically conductive sheet material of claim 1, wherein the metal traces are photo-conductive.

6. The electrically conductive sheet material claim 5, wherein the photoconductive metal traces comprise selenium.

7. The electrically conductive sheet material of claim 1, wherein the polymer substrate is a thermoformable material.

8. The electrically conductive sheet material of claim 1, wherein the polymer substrate is an elastomeric material.

9. The electrically conductive sheet material of claim 1, wherein the channels have a triangular cross section.

10. The electrically conductive sheet material of claim 1, wherein the metal is selected from the group of copper, tin, silver, lead, or bismuth.

11. The electrically conductive sheet material of claim 1, wherein the substrate is a fluoropolymer.

12. The electrically conductive sheet material of claim 1, wherein the substrate is a perfluorinated polymer.

13. The electrically conductive sheet material of claim 1, wherein the substrate is a partially fluorinated polymer.