Electrical devices

• US 6,651,315 B1
• Filed: 10/27/1998
• Issued: 11/25/2003
• Est. Priority Date: 07/09/1992
• Status: Expired due to Fees

• Current Assignee: Littelfuse Incorporated
• Original Assignee: Tyco Electronics Corporation (TE Connectivity Ltd. (United Kingdom))
• Inventors: Thompson, Mark, Chandler, Daniel, Graves, Gregory A., Siden, Dennis, Zhang, Michael Mengruo, Chan, Chi-Ming, Fang, Shou-Mean
• Primary Examiner(s): Arbes, Carl J.
• Assistant Examiner(s): TRINH, MINH N
• Application Number:
  US09/181,028
• Time in Patent Office: 1,855 Days
• Field of Search: 298/52, 296/21, 296/101, 296/22, 298/30, 298/31, 298/32, 298/33, 298/40, 298/41, 338/22.R, 338/313, 338/314, 338/332, 338/328
• US Class Current: 29/621
• CPC Class Codes: C12N 9/503 derived from viruses
• CPC Class Codes: C12N 9/52 derived from bacteria or Archaea
• CPC Class Codes: H01C 1/14 Terminals or tapping points or electrodes specially adapted for resistors in general H01R; Arrangements of terminals or tapping points or electrodes on resistors
• CPC Class Codes: H01C 1/1406 Terminals or electrodes formed on resistive elements having positive temperature coefficient
• CPC Class Codes: H01C 17/06586 composed of organic material
• CPC Class Codes: H01C 7/027 consisting of conducting or semi-conducting material dispersed in a non-conductive organic material
• CPC Class Codes: H05K 1/182 associated with components mounted in the printed circuit board, e.g. insert mounted components [IMC]
• CPC Class Codes: H05K 1/184 Components including terminals inserted in holes through the printed circuit board and connected to printed contacts on the walls of the holes or at the edges thereof or protruding over or into the holes
• CPC Class Codes: H05K 2201/09181 Notches in edge pads
• CPC Class Codes: H05K 2201/09954 More mounting possibilities, e.g. on same place of PCB, or by using different sets of edge pads
• CPC Class Codes: H05K 2201/10022 Non-printed resistor
• CPC Class Codes: H05K 2201/10469 Asymmetrically mounted component
• CPC Class Codes: H05K 2201/10643 Disc shaped leadless component
• CPC Class Codes: H05K 2201/10666 Plated through-hole for surface mounting on PCB
• CPC Class Codes: H05K 3/0097 Processing two or more printed circuits simultaneously, e.g. made from a common substrate, or temporarily stacked circuit boards H05K3/0052 takes precedence
• CPC Class Codes: H05K 3/3442 having edge contacts, e.g. leadless chip capacitors, chip carriers
• CPC Class Codes: H05K 3/403 Edge contacts; Windows or holes in the substrate having plural connections on the walls thereof H05K3/4092 takes precedence
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product
• CPC Class Codes: Y10T 29/49085 Thermally variable
• CPC Class Codes: Y10T 29/49101 Applying terminal
• CPC Class Codes: Y10T 29/49103 : Strain gauge making

Abstract

An electrical device which comprises first and second laminar electrodes and a laminar PTC resistive element sandwiched between them, the device comprising:

(a) a main portion which comprises a main part of the first electrode, a main part of the second electrode, and a main part of the resistive element; and

(b) a first connection leg which extends away from the main portion and which comprises a first leg part of the first electrode which is integral with the main part of the first electrode, and a first leg part of the resistive element which is integral with the main part of the resistive element.

Such devices can be secured to circuit boards in a variety of ways, and to elastically deformed terminals. Preferably preferred devices contain two laminar electrodes, with a PTC element between them, and a cross-conductor which passes through the thickness of the device and contacts one only of the two electrodes. The cross-conductor permits connection to both electrodes from the same side of the device, and also makes it possible to carry out the steps for preparing such devices on an assembly which corresponds to a number of individual devices, with division of the assembly as the final step.

Claims

1. A method of making an electrical device which comprises

(1) a first laminar electrode;

(2) a second laminar electrode; and

(3) a laminar resistive element which exhibits PTC behavior and has a first face to which the first electrode is secured and an opposite second face to which the second electrode is secured;

the device comprising

(a) a main portion which comprises

(i) a main portion of the first electrode,

(ii) a main part of the second electrode, and

(iii) a main part of the resistive element;

(b) a first connection leg which extends away from the main portion and which comprises

(i) a first leg part of the first electrode which is integral with the main part of the first electrode, and

(ii) a first leg part of the resistive element which is integral with the main part of the resistive element; and

(c) a second connection leg which extends away from the main portion, which is spaced away from the first connection leg, and which comprises

(i) a second leg part of the second electrode which is integral with the main part of the second electrode, and

(ii) a second leg part of the resistive element which is integral with the main part of the resistive element;

which method comprises

(A) providing a planar laminate which comprises

(1) a first laminar metal member;

(2) a second laminar metal member; and

(3) a laminar resistive member which

(i) lies between the first and second members,

(ii) exhibits PTC behavior, and

(B) cutting a plurality of said electrical devices from the planar laminate such the laminar resistive element of each device comprises a part of the laminar resistive member, the first electrode of each device comprises a part of the first laminar metal member and the second electrode of each device comprises a part of the second laminar metal member;

(C) removing a portion of the second electrode from the first connection leg of each device; and

(D) removing a portion of the first electrode from the second connection leg of each device.

2. A method of making an electrical device which comprises

(A) providing an assembly which comprises

(1) a laminar PTC resistive element which (i) is composed of a resistive material exhibiting PTC behavior and (ii) has a first face and an opposite second face,

(2) a first laminar conductive member which (i) is secured to the first face of the PTC element and (ii) comprises a continuous metal layer, and

(3) a second laminar conductive member which (i) is secured to the second face of the PTC element and (ii) comprises a continuous metal layer;

(B) making a plurality of apertures through the thickness of the assembly provided in step (A), the apertures being arranged in a regular pattern;

(C) simultaneously with step (B), or after step (B), placing a plurality of transverse conductive members within the apertures, in electrical contact with the first laminar conductive member;

(D) removing predetermined portions of at least one of the first and second conductive members; and

(E) after steps (A) to (D), dividing the assembly into a plurality of electrical devices, each device comprising

(1) a part of the PTC resistive element,

(2) a part of the first laminar conductive member, said part providing a first electrode in some of the devices and a second electrode in the other devices,

(3) a part of the second laminar conductive member, said part providing a second electrode in some of the devices and a first electrode in the other devices,

(4) a residual part of the second laminar conductive member, and

(5) at least one transverse conductive member which electrically connects the residual part and the first electrode.

3. A method according to claim 2 where step (D) is accomplished by etching at least one of the first and second conductive members.

4. A method according to claim 2 wherein step (D) is carried out before step (B).

5. A method according to claim 2 wherein step (D) is carried out after step (C).