Apparatus with correlated emitter-detector pairs

摘要

An apparatus such as a touch screen display includes correlated emitter-detector pairs for determining the amount of electromagnetic radiation received at a detector from its paired emitter. The apparatus comprises an array of emitters operable to emit electromagnetic radiation, an array of detectors for detecting the electromagnetic radiation, and drive control circuitry configured to control the array of emitters so that they emit pulses of electromagnetic radiation. The amplitude of the pulses is modulated using mutually orthogonal binary vectors such as a Paley construction of the Hadamard matrix. Each emitter has a different vector associated with it. Detection circuitry is provided to detect the electromagnetic radiation reaching each particular detector in the array of detectors using the mutually orthogonal binary vector associated with the correlated emitter to produce a correlation between particular emitter-detector pairs. The arrangement can discriminate between near field and touching objects.

主权项

1. A touch screen display device having correlated emitter-detector pairs for determining the amount of electromagnetic radiation received at a detector from its paired emitter integrated into the display, the display device comprising:
a touch screen having a back plane and a transparent substrate having a front surface, a plurality of display pixels provided on the back plane, the plurality of display pixels generating an image for display, an array of emitters operable to emit electromagnetic radiation and an array of detectors operable to detect said electromagnetic radiation, drive control circuitry configured to control the array of emitters so that the emitters emit pulses of electromagnetic radiation at substantially the same clock frequency, an amplitude of the pulses being modulated using a set of mutually orthogonal binary vectors, each emitter in the array having a different mutually orthogonal binary vector associated with it, detection circuitry operable to process a signal corresponding to the electromagnetic radiation reaching each particular detector in the array of detectors using the mutually orthogonal binary vector associated with the correlated emitter to produce a detection signal for that particular detector, said detection circuitry being configured to produce a correlation between particular emitter-detector pairs so that a detection signal from a particular detector relates to electromagnetic radiation emitted from the particular emitter of that emitter- detector pair, and processing circuitry coupled to the detection circuitry for processing the detection signals corresponding to each emitter-detector pair to produce a digital representation of the size and/or position of the object, wherein the detection signal is increased by reflection of the electromagnetic radiation from an object near the apparatus, wherein the array of emitters and the array of detectors are interspersed among the display pixels, wherein the electromagnetic radiation emitted at an angle smaller than a critical angle for the transparent substrate is transmitted through the front surface of the transparent substrate and the electromagnetic radiation emitted at an angle greater than the critical angle for the transparent substrate is totally internally reflected at the front surface of the transparent substrate, the processing circuitry thereby determining the electromagnetic radiation that is received by each detector due to direct reflection from a near field object and determining the electromagnetic radiation that is totally internally reflected and frustrated by an object in contact with said front surface and producing digital representations of any such near field and/or contacting objects.