US 4,480,182 AGranted

Single plane optical membrane switch and keyboard

AssigneeBurroughs Corporation

InventorsRichard I. Ely, Carl E. Mosier

Life of this patent

Estimating the term…

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Abstract

Photo-optical switch apparatus useful for example in keyboard switches includes a photopolymerized orthogonal matrix of horizontal and vertical intersecting light channels or guides, monolithically formed by exposure to ultraviolet light on a flat planar, plastic substrate. Each intersection has a refractive index higher than either the channel or the adjacent substrate area. A curved tap or light coupler couples the horizontal to the vertical channel of the array. The intersections of the channels are disposed over an array of upstanding projections on a flat mounting substrate with each projection located at a respective intersection of the horizontal and vertical light channel. A light absorbing key pad is arranged adjacent to each intersection to couple light from the channel up into the key pad. A relative loss of light indicates the key being depressed.

Claims7

Dependent claims

The method of producing single plane optical membrane switch/keyboard apparatus comprising the steps of;

providing a plastic substrate containing a monomer with a known index of refraction;
selectively exposing said substrate to ultra-violet light through a pattern mask effectively photo-polymerizing said monomer and producing individual horizontal light guides in the exposed areas having an index of refraction higher than the original substrate prior to photo-polymerization;
removing the unpolymerized monomer;
rotating said mask;
exposing said substrate to ultra-violet light through the mask photo-polymerizing said monomer and producting individual vertical light guides in the exposed areas;
removing the unpolymerized monomer;
the double exposure of the horizontal and vertical light guides at the points of intersection thereof produces a still higher index of refraction than either the initial substrate or the horizontal and vertical light guides;
providing a light source for said light guides;
providing a light detector for each of said light guides;
and
providing coupling means for coupling the light from the horizontal light guide into the vertical light guide so as to be detected in the vertical light guide.

8 more elements

Dependencies are inferred from the claim text.

Facts

Application: 06/358,822Filed 16 Mar 1982
Granted: 30 Oct 1984
Term ends: Not estimatedThe source records don’t support an estimate.

Classification12 codes

G02B 6/3522
Involving stationary waveguides with moving interposed optical elements: the optical element enabling or impairing total internal reflection
G02B 6/3536
Having switching means: involving evanescent coupling variation, e.g. by a moving element such as a membrane which changes the effective…
H03K 17/9629
Optical touch switches: using a plurality of detectors, e.g. keyboard
H03K 17/9631
Optical touch switches: using a light source as part of the switch