Touch sensitive position encoder using a layered sheet

• US 3,916,099 A
• Filed: 06/21/1974
• Issued: 10/28/1975
• Est. Priority Date: 07/19/1973
• Status: Expired due to Term

• Current Assignee: National Research Council Canada
• Original Assignee: Alvin M. Hlady
• Inventors: Hlady, Alvin M.
• Primary Examiner(s): Robinson, Thomas A.
• Application Number:
  US05/481,896
• Time in Patent Office: 494 Days
• Field of Search: 178/18,19,20 310/9.1,9.7,9.8 340/324R,365R,347AD
• US Class Current: 178/18.04
• CPC Class Codes: G06F 3/0436 in which generating transducers and detecting transducers are attached to a single acoustic waves transmission substrate

Abstract

A touch-sensitive position encoder which provides the position co-ordinates of the location at which a human finger or passive stylus makes contact with the surface of a transparent sheet or plate comprising an extensive transparent sheet, a first transducer positioned at a first position on an edge of said sheet, a second transducer positioned at a second position on an edge of said sheet, a pulsed source of energy connected to said transducers for generating surface waves on said sheet, receiver and timing means connected to said transducers for detecting and timing reflected energy pulses such that the position of the finger of stylus placed on the sheet and causing reflections will be determined in geometric co-ordinate terms, the said extensive transparent sheet being formed of a sheet of material capable of propagating elastic surface waves over its surface and a second sheet or layer bonded to or acoustically coupled to the surface of the first sheet away from that on which the elastic surface waves are to be propagated, said second sheet or layer being of a material capable of absorbing '"'"''"'"''"'"''"'"'bulk'"'"''"'"''"'"''"'"' waves entering therein. In the preferred embodiment, the extensive transparent sheet is formed of two sheets of glass with a plastic layer sandwiched between them.

Claims

1. A touch-sensitive position encoder for computer input comprising:

a. an extensive sheet having a surface suitable for the propagation of elastic surface waves, b. a first transducer positioned at a first position at an edge of said sheet, c. a second transducer positioned at a second position at an edge of said sheet, said transducers being such as to act as radiators and sensors of elastic surface waves on said sheet, d. a pulsed source of energy connected to said transducers for generating surface waves on the sheet, and e. receiver and timing means connected to the transducers for detecting and timing reflected energy pulses such that the position of a human finger or other passive stylus placed on the sheet and causing reflections will determined, f. said extensive sheet having a layered construction formed of a sheet of glass capable of propagating elastic surface waves and a sheet or layer of plastic material capable of absorbing bulk acoustic waves bonded or attached thereto.

2. A touch-sensitive position encoder for computer input comprising:

a. an extensive sheet having a surface suitable for the propagation of elastic surface waves, b. a first transducer positioned at a first position at an edge of said sheet, c. a second trAnsducer positioned at a second position at an edge of said sheet, said transducers being such as to act as radiators and sensors of elastic surface waves on said sheet, d. a pulsed source of energy connected to said transducers for generating surface waves on the sheet, and e. receiver and timing means connected to the transducers for detecting and timing reflected energy pulses such that the position of a human finger or other passive stylus placed on the sheet and causing reflections will determined, f. said extensive sheet having a layered construction formed of two sheets of glass separated by a sheet or layer of material capable of absorbing bulk acoustic waves.

3. A tablet for a touch-sensitive position encoder of the type having an extensive sheet having a surface suitable for the propagation of elastic surface waves, transducers positioned at edges of the sheet and connected to pulsing, receiving and timing circuitry for generating and sensing surface waves on the sheet such that the position of a human finger or other passive stylus placed on the sheet and causing reflections will be determined comprising a layered sheet formed of a first sheet of material capable of propagating elastic surface waves, a second sheet or layer of material capable of absorbing bulk acoustic waves bonded or acoustically coupled thereto, and a third sheet of solid material bonded or affixed to the sheet or layer of material capable of absorbing bulk acoustic waves.

4. A tablet for a touch-sensitive position encoder as in claim 3 wherein the layered sheet has a sandwich construction formed of two sheets of glass with a layer or sheet of plastic material therebetween.

5. A tablet for a touch-sensitive position encoder of the type having an extensive sheet having a surface suitable for the propagation of elastic surface waves, transducers positioned at edges of the sheet and connected to pulsing, receiving and timing circuitry for generating and sensing surface waves on the sheet such that the position of a human finger or other passive stylus placed on the sheet and causing reflections will be determined comprising a layered sheet formed of a first sheet of glass capable of propagating elastic surfaces waves, and a second sheet or layer of plastic material capable of absorbing bulk acoustic waves bonded or acoustically coupled thereto.