Acoustic condition sensor employing a plurality of mutually non-orthogonal waves

• US 20060125804A1
• Filed: 01/20/2006
• Published: 06/15/2006
• Est. Priority Date: 04/19/1995
• Status: Active Grant

• Current Assignee: Elo Touch Solutions, Inc.
• Original Assignee: Joel Kent
• Inventors: Kent, Joel
• Granted Patent: US 7,683,894 B2
• Time in Patent Office: Days
• US Class Current: 345/177
• CPC Class Codes: G06F 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• CPC Class Codes: G06F 3/0436 in which generating transducers and detecting transducers are attached to a single acoustic waves transmission substrate
• CPC Class Codes: H03K 2217/96011 with propagation, SAW or BAW
• CPC Class Codes: Y10S 367/907 Coordinate determination

Abstract

A touch sensor comprising an acoustic wave transmissive medium having a surface; a plurality of acoustic wave path forming systems, each generating a set of incrementally varying paths through said transmissive medium; and a receiver, receiving signals representing said sets of waves, a portion of each set overlapping temporally or physically by propagating in said transmissive medium along axes which are not orthogonal. The waves may also be of differing wave modes. The receiver system may include a phase, waveform or amplitude sensitive system. Reflective arrays are associated with said medium situated along a path, said path not being a linear segment parallel to a coordinate axis of a substrate in a Cartesian space, a segment parallel to an axial axis or perpendicular to a radial axis of a substrate in a cylindrical space, nor parallel and adjacent to a side of a rectangular region of a small solid angle section of a sphere; situated along a path substantially not corresponding to a desired coordinate axis of a touch position output signal; situated along a path substantially non-parallel to an edge of said medium; has a spacing of elements in said array which differs, over at least one portion thereof, from an integral multiple of a wavelength of an incident acoustic wave; has elements in said array which are non-parallel; has an angle of acceptance of acoustic waves which varies over regions of said array; and/or coherently scatter at least two distinguishable acoustic waves which are received by said receiving system.

Claims

1-88. -88. (canceled)

89. A contact sensitive device comprising:

a member capable of supporting propagation of vibrations;

at least one sensor mounted on the member for measuring vibrations in the member, wherein each of the sensors transduces a vibration into an electrical waveform representing the vibration while preserving phase information represented therein; and

a processor responsive to the electrical waveforms of the at least one sensor and analyzing at least the preserved phase information from the electrical waveform, to determine the location of the contact on the member.

90. A contact sensitive device according to claim 89 comprising an absorber at edges of the member whereby reflected waves are suppressed.

91. A contact sensitive device according to claim 90, wherein the absorber and the member are selected so as to reduce reflections of vibrations from the edges of the member.

92. A contact sensitive device according to claim 89, wherein said processor separately analyzes vibrations having different frequencies.

93. A contact sensitive device according to claim 89, comprising four sensors on the member.

94. A contact sensitive device according to claim 89 comprising three or more sensors on the member.

95. A contact sensitive device according to claim 89, wherein the processor analyzes time-dispersion information in the electrical waveform.

96. A contact sensitive device according to claim 89, further comprising an emitting transducer mounted to the member to excite vibrations in the member.

97. A contact sensitive device according to claim 96, wherein the emitting transducer also functions as one of the sensors.

98. A contact sensitive device according to claim 89 wherein the member is transparent.

99. A contact sensitive device according to claim 89 wherein the member is a liquid crystal display screen.

100. A method of determining information relating to a contact on a contact sensitive device comprising:

providing a member capable of supporting vibration propagation and at least one sensor mounted on the member for measuring vibrations in the member;

applying a contact to the member at a location, using the sensors to measure propagated vibrations in the member; and

calculating the location of a contact from the measured propagated vibrations based at least one a phase of the measured propagated vibrations.

101. A method according to claim 100, wherein the plurality of sensors is three or more.

102. A method according to claim 100, comprising suppressing reflected waves by placing an absorber at the edges of the member.

103. A method according to claim 100, wherein the vibrations comprise at least two distinct frequencies, further comprising the step of calculating the location based on an analysis of the vibrations at the at least two distinct frequencies.

104. A computer readable medium for storing a set of instructions readable by a general purpose processor, for performing the steps of:

receiving a signal representing a mechanical vibration on a medium which supports propagation of such vibrations; and

calculating the location of a contact on the medium from the signal by analyzing in phase-sensitive manner characteristics of the measured wave propagation, representing vibrations which propagate from the location of contact at respectively different angles.