Abstract: A touch-sensitive apparatus comprises a panel for conducting signals from incoupling points to outcoupling points. Detection lines are defined between pairs of incoupling and outcoupling points. A signal generator is coupled to the incoupling points to generate the signals. A data processor processes the output signal to generate a set of data samples, which are non-uniformly arranged in a two-dimensional sample space. Each data sample is indicative of detected energy on a detection line and is defined by a signal value and first and second dimension values defining the location of the detection line on the surface portion. Adjustment factors are obtained for the data samples, each adjustment factor being representative of the local density of data samples in the sample space. The data samples are processed by tomographic reconstruction, while applying the adjustment factors, to generate a reconstructed distribution of an energy-related parameter within the surface portion.

Abstract: A coupling element (14) for use in a touch-sensitive apparatus is arranged to transfer light between an electro-optical device (2) and a panel (4) for light transmission. The electro-optical device (2) is an emitter or a detector and has an operative solid angle given by orthogonal device divergence angles. The coupling element (14) is an optical component with a first light transmission surface (21) for facing the electro-optical device (2), and a second light transmission surface (22) for mounting on the panel (4). The coupling element (14) has an optical structure (23) that directs the light between the first and second light transmission surfaces (21, 22) by one or more reflections while expanding one device divergence angle (?x) into a component divergence angle at the second light transmission surface (22). Thereby, the component divergence angle defines a divergence (?p) in the plane of the panel (4) with respect to light propagating by internal reflections inside the light transmissive panel (4).

Abstract: Multi-touch sensitivity is enabled using a touch system that comprises a panel configured to conduct signals, e.g. by FTIR, from a plurality of incoupling points to a plurality of outcoupling points, thereby defining detection lines across the panel between pairs of incoupling and outcoupling points. A signal processor operates in a repeating sequence of iterations to obtain (50) a current signal value for each detection line, and generate (53, 53?) a first interaction pattern and a second interaction pattern as a function of the current signal values, such that the first and second interaction patterns are reconstructed two-dimensional distributions of local interaction with the conducted signals across the surface portion, and represent changes in interaction on different time scales. Thereby, the movement of an object will affect how it is represented in each of the first and second interaction patterns.

Abstract: The disclosure relates to a light out-coupling arrangement for a touch sensitive system comprising a light guide of a material with a refractive index ng and a top surface configured to be exposed to ambient light, and a bottom surface. The out-coupling arrangement comprises at least one detector arranged along the periphery of the light guide and configured to receive the light propagating in the light guide and an optical filter provided between the light guide and the at least one detector. The optical filter has a first side and a second side where the first side is arranged to face the at least one detector, and the second side is arranged to receive light from the light guide.

Abstract: A device implements a method of tracking objects on a touch surface of an FTIR based touch-sensitive apparatus.

Abstract: Touch sensitivity is enabled using a touch system that comprises a panel configured to conduct signals, e.g. by TIR, along detection lines across a touch surface. A signal processor operates to obtain observed values for the detection lines, and identify an interaction pattern on the touch surface as a solution to an optimization function that comprises an aggregation of differences, for each detection line, between the observed value and a projected value, which is given by a projection function that defines a functional relation between the interaction pattern and the projected value for each detection line. The signal processor implements a normalization to ensure that the interaction pattern indicates weak touches even in the presence of strong touches.

Abstract: Multi-touch sensitivity is enabled using a touch-sensitive apparatus comprising a panel for conducting signals from a plurality of incoupling points to a plurality of outcoupling points, thereby defining detection lines between pairs of incoupling and outcoupling points. Signal generators coupled to the incoupling points generate the signals, and signal detectors coupled to the outcoupling points generate an output signal indicative of one or more touches on the surface portion. A signal processor obtains the output signal which, if converted into a set of data samples of a given input format, enables a predetermined reconstruction algorithm to determine an interaction pattern on the surface portion. The signal processor generates, based on the output signal, a modified set of data samples in the given input format; and operates the predetermined reconstruction algorithm on the modified set of data samples so as to determine a modified interaction pattern on the surface portion.

Abstract: Method and touch-sensitive apparatus for determining the amount of visible ambient light incident on the touch-sensitive apparatus comprising a first array of light-sensing elements, the method comprising receiving light signals at a plurality of light-sensing elements in the first array; converting the light signals into electrical signals, identifying at least one type of ambient light source from the signal by comparing features in the signal with characteristic features of one or more known light sources and obtaining information related to the amount of visible ambient light incident on the panel generated by the at least one type of ambient light source in relation to the amount of ambient light registered at the plurality of light-sensing elements.

Abstract: A device obtains a signal representative of objects on a touch surface of a multi-touch sensing apparatus and executes a method for extracting touch data from the signal. The method operates in a sequence of detection frames. Each detection frame comprises the steps of: obtaining (300) the signal; processing (301) the signal for identifying touches; determining (302) a set of identified touches and touch data for the set of identified touches; and outputting (303) the touch data. At least one of the steps of processing (301) and determining (302) includes a prioritization that actively favors certain touches to be identified and included in the set of identified touches, respectively. Temporal prioritization favors a touch that corresponds to a previous touch, which is identified in one or more preceding detection frames. Spatial prioritization favors a touch that is located within at least one predefined subarea on the touch surface.

Abstract: An apparatus is controlled to detect locations of a plurality of objects on a touch surface of a panel. An input scanner arrangement introduces at least three beams of radiation into the panel for propagation by internal reflection, and sweeps the beams inside the panel across a sensing area, preferably in at least two different principal directions. At least one radiation detector is arranged to receive the beams from the input scanner arrangement while they are swept across the sensing area. A data processor is connected to the radiation detector(s) and operated to identify the locations based on an attenuation of the beams caused by the objects touching the touch surface within the sensing area, the attenuation being identifiable from an output signal of the radiation detector(s). Each output signal may be further processed to generate a transmission signal, by dividing the output signal by a background signal which represents the output signal without any object on the touch surface.

Abstract: A touch-sensitive apparatus is configured to define a touch surface on a panel by propagating diverging energy beams across the touch surface inside the panel. Two rows (20A, 20B) of components (2, 3) of a first type that emits energy as a diverging beam and a second type that detects energy are functionally connected to the panel at opposite ends of the touch surface. The rows (20A, 20B) are defined by consecutive component blocks (B) that each contain only components (2, 3) of one type and are defined by type and number of included components. Each row (20A, 20B) is defined to have consecutive component blocks (B) of alternating type. To achieve an improved spatial resolution of the touch-sensitive apparatus for a given number of components, at least one of the rows (20A, 20B) is designed to include at least three different component blocks (B) which differ with respect to at least one of number and type.

Abstract: A device implements a method for estimating the application force of a touching object onto a touch surface in an FTIR-based projection-type touch-sensing apparatus. The apparatus generates projection signals representing radiation that has propagated on a plurality of propagation paths by total internal reflection (TIR) inside a transmissive panel beneath a touch surface of the transmissive panel such that a touching object on the touch surface causes attenuation (frustration) of at least one of the projection signals. The device generates a time series of force values, which represent the application force, based on a time series of magnitude values, which represent a magnitude of a peak in two-dimensional interaction patterns generated by image reconstruction processing of the projection signals, the peak corresponding to the touching object on the touch surface. The force estimation may involve one or more corrections.

Abstract: An interactive display system that may be implemented to provide an electronic whiteboard that enables users to input information to the system by engaging a display with one or more objects. The system may present an image via the display that reflects the inputs received from the user. For example, the display may be dynamically updated to mimic inputs made to a whiteboard by the user via one or more pens and/or an eraser. The interactive display system may implement an underlayer embedded within the display to guide electromagnetic radiation that emanates from an object engaged with the display to one or more detectors by total internal reflection. Due at least in part to the efficiency of the underlayer in guiding the electromagnetic radiation to the detectors, the interactive display system may enhance the speed and/or accuracy of the interpretation of the inputs made by the user.

Abstract: A touch-sensitive apparatus is configured to propagate energy inside a panel (1) so as to define a grid of transmission paths across a touch surface (4) of the panel (1). The apparatus comprises a first subset of components on a first end of the touch surface (4), and a second subset of components on a second end which is opposite to and parallel with the first end. The components include emitters and detectors, each emitter being operable for propagating a diverging energy beam (e.g. radiation) across the touch surface (4) inside the panel (1), and each detector being operable for detecting transmitted energy from at least two emitters. The components in at least one of the first and second subsets are systematically arranged in spatially separate groups along at least one of the first and second ends, so as to achieve a reduced spacing and/or an increased uniformity of the transmission paths along a center line between the first and second ends compared to an equidistant arrangement of all components.

Abstract: An apparatus for determining a location of at least one object on a touch surface, comprising: a light transmissive panel defining the touch surface and including a controllable reflective boundary; an illumination arrangement configured to introduce light into the panel; a control device configured to selectively control the reflective boundary such that the light may pass between a first layer and a second layer via an opening in the reflective boundary; a light detection arrangement configured to measure the light passed via the opening and impinged on the touch surface; and a processor unit configured to determine the location as a function of the measured light passed via the opening and the selective control of the reflective boundary. A method and computer readable medium is also described.

Abstract: A touch-sensing apparatus is based on frustrated total internal reflection (FTIR). The apparatus comprises a panel, in which sheets of light are propagated by internal reflection between a touch surface and an opposite surface. A light sensor arrangement is optically connected to the panel to measure transmitted light energy on detection lines across the touch surface. Each detection line represents a light path across the touch surface from a light source to a light sensor. An object that touches the touch surface will frustrate the propagating light and cause a local attenuation among the detection lines. A data processor is connected to the light sensor arrangement and configured to execute a process for extracting touch-related data.

Abstract: A touch-sensitive apparatus is configured to define a touch surface on a panel by propagating diverging energy beams (e.g. of radiation) across the touch surface inside the panel. Two rows (20A, 20B) of components (2, 3) of a first type that emits energy as a diverging beam and a second type that detects energy are functionally connected to the panel at opposite ends of the touch surface. The rows (20A, 20B) are defined by consecutive component blocks (B) that each contain only components (2, 3) of one type and are defined by type and number of included components. Each row (20A, 20B) comprises a respective sequence (S) of two component blocks (B) of different types and is defined by systematically repeating the sequence (S) along the respective opposite end.

Abstract: A device implements a method of tracking objects on a touch surface of an FTIR based touch-sensitive apparatus. The method repeatedly operates to generate an interaction pattern that indicates local changes in interaction on the touch surface, identify apparent peaks in the interaction pattern, and update existing movement trajectories based on the apparent peaks. An error suppression process is executed at least intermittently in the method to process the apparent peaks and/or the existing movement trajectories to identify implicated trajectories with a potential tracking problem, define two or more movement propositions for each implicated trajectory, and cause an evaluation of the movement propositions in one or more subsequent repetitions of the method. The error suppression process improves tracking by postponing the final decision on how to track the object of the implicated trajectory until more information is available.

Abstract: Touch sensitivity is enabled using a touch system that comprises a panel configured to conduct signals, e.g. by TIR, along detection lines across a rectangular touch surface with first and second spatial dimensions. A signal processor operates to transform energy values for the detection lines into Fourier coefficients arranged as data points on a regular grid defined by first and second frequency dimensions. To generate an interaction pattern for the touch surface, the signal processor operates a first 1D inverse FFT on the data points with respect to the second frequency dimension, so as to generate first values transformed into the second spatial dimension, and operates a second 1D inverse FFT on a selected subset of the first values with respect to the first frequency dimension to generate second values that represent the interaction pattern.

Abstract: A touch-sensing display panel, comprising a plurality of image-forming pixel elements; a planar light guide with a first refractive index, having a front surface forming a touch-sensing region and an opposite rear surface facing the pixel elements; a plurality of light emitters arranged at a peripheral region of the panel to emit light into the light guide for propagation therein through total internal reflection; a plurality of light detectors disposed at the peripheral region for receiving light from the light guide; and an optical layer disposed at the rear surface of the light guide to cover a plurality of the image-forming pixel elements in at least a central region of the panel, wherein said optical layer is configured to reflect at least a part of the light from the emitters impinging thereon from within the light guide.