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Resistively heated small planar filament

  • US 8,247,971 B1
  • Filed: 08/15/2011
  • Issued: 08/21/2012
  • Est. Priority Date: 03/19/2009
  • Status: Expired due to Fees
First Claim
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1. An electron emitter device comprising:

  • a. a pair of spaced-apart bonding pads configured to receive an electrical connection;

    b. an elongated planar filament extending between the pair of bonding pads in a planar layer, the planar filament configured to receive an applied electric current therethrough;

    c. the planar filament being substantially flat with planar top and bottom surfaces;

    d. the planar filament having a length and a width in the planar layer transverse to the length; and

    e. the planar filament winding in an arcuate path in the planar layer between the pair of bonding pads defining;

    i. a central spiral segment with the planar filament forming at least one complete revolution about an axis at a center of the planar filament, on either side of the axis, the planar filament forming a double spiral shape oriented parallel to the layer, andii. a pair of serpentine segments on different opposite sides of the spiral segment with each serpentine segment including at least one change in direction;

    f. the planar filament being continuous and uninterrupted across the width along an entire length of the planar filament and defining a single current path along the length between the pair of bonding pads;

    g. the planar filament having a non-uniform width measured in a plane of the layer and transverse to a length of the planar filament; and

    h. the planar filament including a wider, intermediate portion having a wider width that is greater than narrower portions on opposite ends of the intermediate portion, the wider width being at least twice as wide as the narrower portions, and the wider portion being disposed substantially at the axis at the center of the planar filament.

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