Browse Prior Art Database

IN-MOLDED CIRCUITRY

IP.com Disclosure Number: IPCOM000007134D
Original Publication Date: 1994-Feb-01
Included in the Prior Art Database: 2002-Feb-27
Document File: 3 page(s) / 214K

Publishing Venue

Motorola

Related People

Ari Lima: AUTHOR [+2]

Abstract

The invention of three dimensional circuits has complimented today's emphasis on ever more com- pact packaging designs. Two traditional methods of transferring 3-D circuits to plastic components are double shot molding, and photo imaging. The first involves injecting a catalytic plastic (platable) into a non-catalytic previously molded base. The part is then subjected to a series of plating processes, The second method is photo imaging which is charac- terized by a series of plating, masking, and etching operations. The proposed method has several advan- tages over these complex traditional methods.

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Technical Developments Volume 21 February 1994

IN-MOLDED CIRCUITRY

by Ari Lima and Allen Hertz

  The invention of three dimensional circuits has complimented today's emphasis on ever more com- pact packaging designs. Two traditional methods of transferring 3-D circuits to plastic components are double shot molding, and photo imaging. The first involves injecting a catalytic plastic (platable) into a non-catalytic previously molded base. The part is then subjected to a series of plating processes, The second method is photo imaging which is charac- terized by a series of plating, masking, and etching operations. The proposed method has several advan- tages over these complex traditional methods.

  A second application might be to transfer an RF shield directly onto the housing over magneti- cally sensitive areas. Not shown.

  Antennas can be in molded with several advan- tages over conventional designs. Maximum surface areas can be utilized without affecting the overall size of the packaging. Electrically optimized metals can be used and selectively coated with an insulat- ing barrier (similar to the hardcoat used on decora- tive surfaces). See Figure 3.

  A fourth and very unique application is to use decorative surfaces, such as icons, logos, etc. as con- ductive pads. These external features can be bridged by actuator popples which when depressed serve as a switch. Such applications are shown in Figure 4. Connection to the PCB may be accomplished by adding plated through holes.

  These are only a few of the possible applica- tions. Additions to this list can be numerous and generate as unique applications arise.

DESCRIPTION:

  The proposed method utilizes transfer techniques originated for in mold decorating. In mold decorat- ing begins by laminating decorative patterns onto a polyester film. The film carrier roll is then indexed and the laminating step repeated. A hardcoat layer can also be applied to the inks if desirable. Once a predetermined number of images have been trans- ferred the carrier is slit and packaged in roll form, The roll is then attached above a modified injection molding machine. The leading edge is fed between the front and back plates and attached to a pick up roll core. The image is transferred when the plastic is injected into the mold. The bond between the inks and the plastic is created by ditfusion. The car- rier roll is then indexed and anot...