Abstract: A method and apparatus for adapting an acoustic touchscreen controller to the operating frequency requirements of a specific touchscreen are provided. The adaptive controller can either utilize look-up tables to achieve the desired output frequency or the it can use a multi-step process in which it first determines the frequency requirements of the touchscreen, and then adjusts the burst frequency characteristics, the receiver circuit center frequency, or both in accordance with the touchscreen requirements. In one embodiment, the adaptive controller compensates for global frequency mismatch errors. In this embodiment a digital multiplier is used to modify the output of a crystal reference oscillator. The reference oscillator output is used to control the frequency of the signal from the receiving transducers and/or to generate the desired frequency of the tone burst sent to the transmitting transducers.

Abstract: A switch comprises two substrates coated with conductive elements opposed to each other across a gap. At least one of the conductive elements comprises an intrinsically conductive polymer. The switch completes an electrical circuit when one of substrates is pressed toward the other of the substrates and the two conductive elements touch. The polarity applied to the intrinsically conductive polymer coating is, preferably, negative. The voltage applied to the electrical circuit, is, preferably, less than five volts; more preferably, the voltage applied to the electrical circuit is less than three volts; even more preferably, the voltage applied to the electrical circuit is less than one volt.

Abstract: An acoustic touch panel or “touch screen” utilizes acoustic waves within a sensor substrate to determine the position of touch. The substrate is made of a temperable glass having an attenuation coefficient of less than or equal to about 0.6 dB/cm as determined at the substrate surface for 5.53 MHz Rayleigh waves as measured by the slope of a plot of amplitude versus distance for a signal through a pair of facing 0.5-inch wide wedge transducers mounted on a sample of the glass type under test having sufficient thickness to support Rayleigh wave propagation. An acoustic touch panel with a tempered low-acoustic-loss glass substrate. This makes possible large tempered acoustic touch panels. A glass substrate of the touch sensor comprises SiO2 as the main component with a total content of Na2O, CaO and MgO of 20% by weight or less and a total content of Al2O3, ZrO2, TiO2, B2O3, Y2O3, SnO2, PbO2, In2O3 and K2O of 5% by weight or more.

Abstract: A touch system using a plurality of infrared (“IR”) transmitters and receivers, and a method of determining with increased resolution the location of a touch between the IR transmitters and receivers using on-axis and off-axis detection are disclosed. The inventive touch system and method use, in conjunction with the on-axis and off-axis detection, a coarse and fine sweep of the transmitters and receivers to increase the resolution of identified touch location. The method of determining a touch location involves selection and activation of particular off-axis infrared transmitter and receiver pairs determined from a triangulation interdependence between the x and y coordinates. The increased resolution of the identified touch location is achievable using the inventive system and method without the need for an increased number of IR transmitters and receivers and without the need for higher speed processing capability.

Abstract: A sealing system for use with acoustic touchscreens is provided. The system includes a seal coupled to a frame, the frame being positioned directly over the acoustic touchscreen components, e.g., acoustic transducers, reflective arrays, etc. such that the seal prevents contamination of the underlying components. The system uses a plurality of tensioning elements that are either integral to, or separate from, the frame. The tensioning elements are preferably coupled at the four corners of the CRT, and more preferably coupled to the CRT mounting tabs. Assuming an approximately spherically curved touchscreen surface, the tensioning elements provide a uniform compressive force per unit length along the entire perimeter of the seal. As a consequence of the tensioning elements, the frame can be extremely thin, lightweight, and flexible, thus allowing it to substantially conform to the shape of the touch surface. Additionally, a very small and uniform gap can be maintained between the frame and the touch surface, e.

Abstract: A method and apparatus for adapting an acoustic touchscreen controller to the operating frequency requirements of a specific touchscreen are provided. The adaptive controller can either utilize look-up tables to achieve the desired output frequency or the it can use a multi-step process in which it first determines the frequency requirements of the touchscreen, and then adjusts the burst frequency characteristics, the receiver circuit center frequency, or both in accordance with the touchscreen requirements. In one embodiment, the adaptive controller compensates for global frequency mismatch errors. In this embodiment a digital multiplier is used to modify the output of a crystal reference oscillator. The reference oscillator output is used to control the frequency of the signal from the receiving transducers and/or to generate the desired frequency of the tone burst sent to the transmitting transducers.

Abstract: A method for minimizing the shadowing effects of a contaminant on a surface acoustic wave touchscreen is provided. The disclosed system compares the measured waveform against a baseline waveform for each axis and validates the new touch if the measured waveform is different from the baseline waveform for either axis. As a consequence of this approach, even if the new touch lies within the shadow created by a contaminant in one axis, the new touch is still validated as it is not within the shadow created by the contaminant in the second axis. In one embodiment, after the system determines that the measured response is different from the baseline in at least one axis, the system compares the new touch to one or more selection criteria to insure that it is a valid touch and not due to a contaminant, electrical noise, or other improper source.

Abstract: An improved touchscreen utilizing two sets of electrodes that are fabricated in a single plane is provided. The individual electrodes of each set of electrodes are formed from a continuous length of a conductive material. Suitable electrode materials include fine wire and deposited conductive coatings. The overall electrode pattern is such that there is no overlap of electrodes, thus eliminating the need for insulating layers and/or coatings between electrodes. Although a variety of electrode patterns can be used, preferably the pattern is comprised of a plurality of approximately triangularly shaped electrodes, the pattern such that the base of one triangularly shaped electrode is adjacent to the apex of the next triangularly shaped electrode.

Abstract: A sealing system for an acoustic touchscreen includes an elongate gel body between the touchscreen and the bezel of a housing onto which the touchscreen is mounted. The elongate gel body forms a seal around the perimeter of the touch-sensitive area of the touchscreen. A stop element controls and limits the amount of compression of the elongate gel body. The resulting seal is highly effective in protecting the unexposed parts of the touchscreen (i.e., areas other than the touch-sensitive area) from contaminants, especially liquid contaminants, at the cost of an acceptably low loss in acoustic signal strength.

Abstract: An acoustic touch panel or “touch screen” utilizes acoustic waves within a sensor substrate to determine the position of touch. The substrate is made of a temperable glass having an attenuation coefficient of less than or equal to about 0.6 dB/cm as determined at the substrate surface for 5.53 MHz Rayleigh waves as measured by the slope of a plot of amplitude versus distance for a signal through a pair of facing 0.5-inch wide wedge transducers mounted on a sample of the glass type under test having sufficient thickness to support Rayleigh wave propagation. An acoustic touch panel with a tempered low-acoustic-loss glass substrate. This makes possible large tempered acoustic touch panels. A glass substrate of the touch sensor comprises SiO2 as the main component with a total content of Na2O, CaO and MgO of 20% by weight or less and a total content of Al2O3, ZrO2, TiO2, B2O3, Y2O3, SnO2, PbO2, In2O3 and K2O of 5% by weight or more.

Abstract: A touchscreen is constructed directly on the glass surface of a cathode ray tube (CRT). To solve the problem of insufficient space between the CRT's bezel and frontal region to accommodate the transducers for the touchscreen, the transducers are moved away from the frontal region, to the highly curved shoulder region of the CRT. To preserve acoustic signal strength, the positioning of the transducers is chosen to take advantage of the fact that an acoustic wave on a non-Euclidean surface travels along a geodesic path. Allowance is also made for the acoustic lens and prism effect of the corner regions of the CRT, where the transducer may be located.

Abstract: An acoustic touch sensing device, comprising a substrate, having a surface; and an acoustic wave transducer, transducing a bulk wave in said substrate propagating through said substrate along an axis intersecting said surface, wherein energy of said bulk wave is coupled to a wave having a converted wave mode with appreciable energy at said surface and propagating along said surface. The device may include a set of scattering centers to couple the bulk wave to a Rayleigh wave or plate wave. The Rayleigh wave or plate wave may be dispersed over a region of the substrate, and analyzed to detect a perturbation indicative of a position of touch.

Abstract: A touch sensor, having an acoustic wave transmissive medium having a surface and a touch sensitive portion of the surface, a transducer system for emitting acoustic energy into the medium, and a receiver system for receiving the acoustic energy from the substrate as at least two distinct sets of waves, a portion of each of which overlap temporally at the receiver system or overlap physically by propagating in the touch sensitive portion along axes which are substantially non-orthogonal, the receiver system determining a position or a waveform perturbing characteristic of a touch on the touch sensitive portion. The receiver may be an amplitude detector or be sensitive to a phase-amplitude characteristic of the received acoustic waves.

Abstract: A general method is described for producing an inexpensive touchscreen system that provides accurate positional information and compensates for manufacturing variations without complicated sensor arrangements. Utilizing a set of sensed signals that are unique to each location on the touchscreen sensor, equations for X and Y are derived via curve fitting methods. The coefficients of the equations are stored with the sensor. During touchscreen operation the coefficients are used to calculate X and Y to the desired accuracy directly and independently.

Abstract: A touch sensor, having an acoustic wave transmissive medium having a surface and a touch sensitive portion of the surface, a transducer system for emitting acoustic energy into the medium, and a receiver system for receiving the acoustic energy from the substrate as at least two distinct sets of waves, a portion of each of which overlap temporally at the receiver system or overlap physically by propagating in the touch sensitive portion along axes which are substantially non-orthogonal, the receiver system determining a position or a waveform perturbing characteristic of a touch on the touch sensitive portion. The receiver may be an amplitude detector or be sensitive to a phase-amplitude characteristic of the received acoustic waves.

Abstract: An improved touch sensor having a resistive surface and simplified corner electrodes for introducing electrical potentials into the resistive surface. Improved positional accuracy is achieved by selectively energizing the touch sensor transversely (either vertically or horizontally) and diagonally, in either direction. As a result, equipotential lines formed in this manner are nearly perpendicular to each other (from the two energizations) throughout a larger area of the touch sensor so that increased accuracy of position coordinates is achieved over this larger area. Provision is made to determine the quadrant of touch and to optimize the energization to achieve the increased accuracy in that particular quadrant of touch.

Abstract: An acoustic wave touch sensor comprising an acoustic wave transducer, for transducing an acoustic wave; a substrate, having a front surface. A surface bound acoustic wave interface, having at one least bevel edge, is provided, having an transmitted acoustic wave signal attenuation of less than about 3 dB. The acoustic wave transducer is mounted to transmit the acoustic wave through the interface into the substrate, so that the energy of the acoustic wave appears at the surface. The acoustic wave transducer is mounted on a beveled region of the substrate, inclined to the front surface. The beveled edge has an effective radius which is small as compared to the wavelength and a bevel angle such that the acoustic wave is attenuated by less than about 3 dB on transmission across the edge. In this manner, means are provided to recess transducers for improved product robustness and compactness of design.

Abstract: A touch position sensor or "touchscreen" utilizes acoustic waves within a sensor substrate to determine the position of touch. The substrate is made of a transparent material, such as borosilicate glass or a barium glass, which exhibits substantially less acoustic absorption than soda-lime glass.

Abstract: A graphical user interface system is provided having an event-driven control program with a unified user input pointing event stream without distinction of source and a graphical user interface having a virtual display space containing objects. The control program processing events related to a plurality of user inputs representing different locations within the virtual display space, and operates optionally in two modes. A first mode permits the plurality of user inputs to interact, allowing an object in the virtual display space at a first location specified by an initial user input to be associated with a second location specified by a concurrent and subsequently terminating user input. In this case, the control program has a counter which increments on activity of any user input and decrements on cessation of activity of any user input, for determining an initial user input condition, temporal concurrence of a plurality of user inputs, and a terminal user input condition.

Abstract: An acoustic touch position sensor having a transducer which imparts a wave, propagating along a first axis. A reflective array disposed along the first axis which reflects the wave as a set of waves having a horizontally polarized component and a non-uniform volumetric energy density along an axis normal to said surface, traveling along a different axis into the touch surface region of the substrate. The waves are partially absorbed, attenuated or perturbed by an object touching the substrate, to create a modified waveform having characteristics indicative of the axial displacement and/or contact condition of the object with the substrate. The wave perturbation is detected by collecting the set of waves with a reflective array, which redirects the wave energy to a receiving transducer. The transducers preferably produce and are responsive to Rayleigh type waves, with the reflective arrays mode-converting acoustic wave energy between higher order horizontally polarized shear waves and Rayleigh type waves.