Touch-panel input device
AssigneeSMK Corporation
InventorsToshifumi Maeda, Hiroshi Tanaka
Life of this patent
Estimating the term…
Abstract
Two transparent conductive panels are separated by a perimeter of elastic adhesive that forms a sealed gap in which transparent insulative fluid is interposed. The fluid has a refraction index close to that of the panels to improve light transmittance through the device. The small width of the gap improves response time and prevents formation of a vacuum in the gap. The panels are connected to a position detection circuit that determines coordinate position of an applied pressure point. Spacers in the gap reduce the chance of accidental large-area contact which would result in an erroneous position command. The elasticity of the adhesive and the small gap width provide better temperature variation tolerance in addition to improved consistency and reliability of operation.
Claims29
A touch-panel input device comprising:
- at least first and second transparent plates having faces opposed to one another and substantially parallel;
- a portion of said opposing faces of said at least first and second transparent plates being transparent electrically conductive surfaces with uniform surface resistance;
- an elastic adhesive disposed around a perimeter of said conductive surfaces, whereby said opposing faces are bonded together and separated by a sealed gap having a uniform width;
- a transparent insulative fluid interposed in said sealed gap, said fluid having a refraction index close to that of said transparent plates;
- at least one of said at least first and second transparent plates capable of resiliently flexing toward an other of said transparent plates, whereby an electrical relationship is changed between said conductive surfaces;
- and
- said relationship is related to a coordinate position on said device.
A method for constructing a touch-panel input device comprising steps of:
- forming transparent conductive layers with conductive leads on portions of at least two transparent plates;
- disposing a curable reactive adhesive on a perimeter of one of said conductive layers;
- curing said reactive adhesive to form an elastic pressure sensitive adhesive with a specified height above said transparent plate;
- applying a conductive bonding agent to an external connector;
- positioning said external connector in a region outside of a space defined by said adhesive and in contact with said conductive leads;
- pressing said transparent plates together with said conductive layers being opposed thereby bonding said transparent plates together and forming a sealed gap between said conductive layers;
- and
- interposing an insulative transparent fluid in said gap, said fluid having a refraction index near that of said transparent plates.
A touch-panel input device comprising:
- at least first and second transparent plates having faces opposed to one another and substantially parallel;
- transparent electrically conductive layers disposed on each of said opposing faces, said conductive layers having substantially uniform surface resistance and transparent electrical connection leads disposed on opposing ends of said conductive layers;
- pairs of said connection leads of said conductive layers defining a coordinate axis;
- regularly spaced insulative protrusions on at least one of said conductive layers effective to slightly increase and evenly distribute pressure applied to said transparent plates needed to cause contact between said conductive layers;
- an elastic adhesive disposed around a perimeter of said conductive layers, whereby said opposing faces are bonded together and separated by a sealed gap having a substantially uniform width;
- transparent insulative fluid interposed in said sealed gap, said fluid having a refraction index close to that of said transparent plates;
- and
- an external connector connected to said leads.
Dependencies are inferred from the claim text.