Method of applying an electrical conductor pattern on an apertured substrate

• US 4,522,671 A
• Filed: 11/12/1982
• Issued: 06/11/1985
• Est. Priority Date: 11/17/1981
• Status: Expired due to Fees

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Schmidt, Ewald, Pfizenmaier, Heinz, Schmid, Kurt, de la Prieta, Claudio, Grunwald, Werner
• Primary Examiner(s): Kimlin, Edward
• Assistant Examiner(s): FALASCO, LOUIS V
• Application Number:
  US06/441,033
• Time in Patent Office: 942 Days
• Field of Search: 156/215, 156/214, 156/230, 156/235, 156/240, 156/277, 156/249, 156/293, 156/493, 156/488, 156/233, 156/85, 156/90, 156/102, 156/144, 156/289, 156/304.2, 29/602 R, 29/605, 29/606, 29/DIG. 1, 427/104, 336/200, 336/208, 101/34
• US Class Current: 156/235
• CPC Class Codes: H01F 17/0006 Printed inductances printed coils for dynamo-electric machines H02K3/26; printed circuits H05K
• CPC Class Codes: H01L 21/705 of thick-film circuits or parts thereof
• CPC Class Codes: H05K 1/0284 Details of three-dimensional rigid printed circuit boards H05K1/119 takes precedence; shaping of the substrate H05K3/0014
• CPC Class Codes: H05K 1/095 for polymer thick films, i.e. having a permanent organic polymeric binder
• CPC Class Codes: H05K 1/165 incorporating printed inductors
• CPC Class Codes: H05K 2201/09645 Patterning on via walls; Plural lands around one hole
• CPC Class Codes: H05K 2203/0534 Offset printing, i.e. transfer of a pattern from a carrier onto the substrate by using an intermediate member
• CPC Class Codes: H05K 3/1275 by other printing techniques, e.g. letterpress printing, intaglio printing, lithographic printing, offset printing
• CPC Class Codes: H05K 3/4069 for via connections in organic insulating substrates
• CPC Class Codes: Y10T 29/4902 Electromagnet, transformer or inductor

Abstract

To make inductance elements, thick film electrically conductive paste, which may include precious metal such as silver, are applied by a deformable stamp on a ferrite core which, for example, can be someone hump shaped, for adhesion to a carrier (30) and formed with openings thereto, the stamp being shaped to fit within the opening and deforming to penetrate the opening to apply the thick film conductive paste in form of conductive tracks thereon. Conductive tracks can be applied, previously, to a substrate carrier (30), which are then joined by the paste strips to form interconnected windings (FIGS. 1a, 1b); or the ferrite may be in form of a toroidal core (34), on which the conductive tracks are applied around all surfaces, to form connected windings thereon, the deformable stamp having a projecting tip which can fit within the opening of the toroidal core.

Claims

1. Method of making an electrical inductance, comprising the steps of

providing a carrier of insulating material (30);

applying a pattern of conductive tracks (31) forming partial windings, or portions of windings, on a surface of said carrier;

applying a core body (32) of ferrite material on the surface of said carrier, said core body having a core surface and a through-opening through the body extending to the carrier surface;

providing an elastically deformable printing stamp having a penetrating portion which is dimensioned to enter into the through-opening (32a) of the core body;

applying to a surface of said deformable printing stamp, including a surface of said penetrating portion, a pattern of an electrically conductive paste in the form of conductive tracks, positioned to connect with the conductive tracks (31) applied on the carrier surface (30), when the conductive paste is transferred to the core body (32);

pressing said printing stamp, with the paste applied thereto, against a surface of the core body including the region of the aperture, with sufficient pressure to deform the printing stamp to the extent that the penetrating portion thereof penetrates within the aperture, and said surface of the stamp engages the surface defining the aperture of the core body to transfer at least a portion of the conductive paste on the surface of the core body, including the surface of said aperture, the conductive tracks (31) being applied on the carrier and the transferred paste forming closed conductive loops extending on both sides of the ferrite core body.

3. Method according to claim 1 wherein said carrier (30) has a flat surface;

said ferrite core has a flat surface matching the flat surface of said carrier;

and further including the step of adhesively securing the ferrite core (32) to said carrier, after the step of applying the conductive tracks (31) on the carrier has been carried out.

2. Method according to claim 10 wherein the step applying the electrically conductive paste to the deformable stamp comprises applying said paste in a pattern which is predistorted so that the pattern of application will conform to a desired conductive pattern after deformation of the printing stamp upon penetration, at least in part, within the aperture of the substrate.

4. Method of making a toroidal inductance, comprising the steps of

providing a ring-shaped ferrite core (35) having a central aperture (38), and end surfaces (37);

providing an elastically deformable printing stamp having a penetrating portion which is dimensioned to enter into said aperture (38) of the ring-shaped core;

applying to a surface, including said penetrating portion of said deformable printing stamp, a pattern of an electrically conductive paste in form of conductive tracks;

pressing said printing stamp, with the paste applied thereto, against the core, and penetrating the opening within the toroidal core by the penetrating portion of the printing stamp, and applying the tracks of conductive paste to the interior of the aperture, while also applying tracks of the conductive paste to the end surfaces (37) of the toroidal core, and completing an electrical inductance circuit by applying a second pattern of electrical tracks to the outer surface (39) of the core;

said step of pressing the printing stamp against the toroidal core including the step of applying sufficient pressure to deform the printing stamp to the extent that the penetrating portion penetrates within the aperture and the stamp further engages the facing surfaces to transfer at least a portion of the conductive paste from the printing stamp to at least a portion of the surface of the aperture and a portion of the end surfaces of the toroidal core.

5. Method according to claim 4 wherein the step of pressing said printing stamp against a surface of the ring-shaped toroidal core and penetrating the opening comprises penetrating only a portion of the opening;

and then repeating the step of pressing the printing stamp with the conductive paste applied thereto from a mirror image surface of the toroidal core thereagainst and penetrating the opening within the toroidal core from the other side by said stamp to apply the printing paste in the form of a continuous conductive track in the aperture of the toroidal core.

6. Method according to claim 5, wherein the toroidal core includes a cylindrical outer surface (39);

and said method includes the step of applying conductive tracks to the cylindrical outer surface, in electrically conductive communication with the conductive tracks applied to the end face of the toroidal core.

7. Method according to claim 4, wherein the toroidal core includes a cylindrical outer surface (39);

and said method includes the step of applying conductive tracks to the cylindrical outer surface, in electrically conductive communication with the conductive tracks applied to the end faces of the toroidal core.