Circuit board having conductor runs resistant to formation of non-conductive localized areas and method

Claim 2

In combination with a circuit board comprising a non-conductive substrate having electrical circuitry affixed thereto, the improvement which comprises: electrical conductor runs forming a part of said electrical circuitry adhered to and carried on said substrate, said conductor runs comprising small vitreous bead-like particles having a thin silver coating carried thereon with the surface of said silver-coated bead-like particles comprising a triazole-silver water-insoluble reaction product, said bead-like particles adhered to said substrate by a matrix of organic polymer binder, and the relative proportion of said bead-like particles to said polymer binder being such that adjacently positioned bead-like particles are in electrically conductive relationship with one another to provide a resistivity of less than about 0.03 ohm-cm for said runs, whereby said triazole reacted surface of said bead-like particles substantially inhibits the formation of non-conductive localized areas in said conductor runs.

Claim 3

The circuit board of claim 1, wherein said conductor runs comprise said triazole reacted silver-coated vitreous bead-like particles in amount from about 86 to 94 wt. %, and said organic polymer binder in amount from about 6 to 14 wt. %.

Claim 4

The circuit board of claim 1, wherein said relative proportion of said bead-like particles to said polymer binder provides a resistivity of about 0.0022 ohm-cm.

Claim 5

In combination with a flash lamp array including a plurality of flash lamps and a circuit board comprising a non-conductive substrate having sequencing electrical circuitry affixed thereto for sequentially flashing said lamps, the improvement which comprises: electrical conductor runs forming a part of said sequencing circuitry adhered to and carried on said substrate, said conductor runs comprising small vitreous bead-like particles having a thin silver coating carried thereon with the surface of said thin silver-coated bead-like particles comprising a triazole-silver water-insoluble reaction product, said bead-like particles adhered to said substrate by a matrix of organic polymer binder, and the relative volume proportion of said bead-like particles to said polymer binder being such that adjacently positioned bead-like particles are in electrically conductive relationship with one another to provide a resistivity of less than about 0.03 ohm-cm for said runs, whereby said triazole reacted surface of said bead-like particles substantially inhibits the formation of non-conductive localized areas in said conductor runs.

Claim 6

In combination with a flash lamp array including a plurality of flash lamps and a circuit board comprising a non-conductive substrate having sequencing electrical circuitry affixed thereto for sequentially flashing said lamps, the improvement which comprises: electrical conductor runs forming a part of said sequencing circuitry adhered to and carried on said substrate, said conductor runs comprising small vitreous bead-like particles having a thin silver coating carried thereon with the surface of said thin silver-coated bead-like particles comprising a triazole-silver water-insoluble reaction product, said bead-like particles adhered to said substrate by a matrix of organic polymer binder, and the relative volume proportion of said bead-like particles to said polymer binder being such that adjacently positioned bead-like particles are in electrically conductive relationship with one another to provide a resistivity of less than about 0.03 ohm-cm for said runs, whereby said triazole reacted surface of said bead-like particles substantially inhibits the formation of non-conductive localized areas in said conductor runs.

Claim 7

The array of claim 4, wherein said conductor runs comprise said triazole reacted silver-coated vitreous bead-like particles in an amount from about 86 to 94 wt. %, said organic polymer binder in an amount from about 6 to 14 wt. %.

Claim 10

The method of claim 6, wherein hydrophobic silica is mixed together with said silver-coated bead-like particles, said organic polymer binder and said organic solvent to form said circuit link.

Claim 11

The method of claim 7, wherein said aqueous benzotriazole solution has a 2% concentration of benzotriazole.

Claim 12

The method of claim 6, wherein said silver-coated vitreous bead-like members have a nominal particle size of about 19 microns.

Claim 13

The method of claim 6, wherein said silver-coated vitreous bead-like members contain about 8% by weight silver.

Claim 14

The method of claim 6, wherein said organic polymer binder comprises polyvinyl butyral resin.

Claim 15

The method of claim 6, wherein said organic solvent comprises ethylene glycol monobutyl ether acetate and benzyl alcohol.

Claim 16

The method of claim 6, wherein said silver-coated vitreous bead-like particles comprise from about 56 to 79 wt. % of said circuit ink; said organic polymer binder comprises from about 5 to 9 wt. % of said circuit ink; and said organic solvent comprises from about 16 to 35 wt. % of said circuit ink.

Claim 17

The method of claim 7, wherein said hydrophobic silica comprises from about 0.25 to 0.4 wt. % of said circuit ink.

Claim 18

The method of claim 7, wherein said hydrophobic silica has a nominal particle size of about 0.007 and an average surface area of 225 m 2 /gm.

Claim 19

The method of claim 6, wherein said circuit ink is dried at about 70° C. for about 10 minutes.