초록 ▼

A touch entry system employing arrays of emitter and detector opto devices located around the periphery of an irradiated field detects intrusion of an opaque element such as a stylus within the field. The detector analog output is converted to a digital signal for input into a microprocessor. Digita

A touch entry system employing arrays of emitter and detector opto devices located around the periphery of an irradiated field detects intrusion of an opaque element such as a stylus within the field. The detector analog output is converted to a digital signal for input into a microprocessor. Digital signals input into the microprocessor can vary due to inconsistencies in conventional opto devices. A programmable amplifier responsive to the microprocessors preconditions the analog signals prior to analog to digital conversion to bring all digital signals corresponding to the unblocked emitter beam condition within a normalized range before input into the microprocessor.

대표청구항 ▼

A method of detecting an input to a touch sensitive device comprising an array of light emitters and an array of light detectors located on the periphery of a display field, the light emitters and the light detectors being configured in aligned emitter/detector pairs, such that intrusion of an opaqu

A method of detecting an input to a touch sensitive device comprising an array of light emitters and an array of light detectors located on the periphery of a display field, the light emitters and the light detectors being configured in aligned emitter/detector pairs, such that intrusion of an opaque element into the display field blocks light between associated emitters and detectors in at least one emitter/detector pair, the method comprising the steps of: sequentially energizing emitter/detector pairs prior to intrusion of an opaque element; converting an analog signal from each detector to a digital signal and inputing the digital signal into digital computing means; comparing each digital signal with a normalized range and storing the digital signal in memory; separately amplifying subsequent analog signals from each detector prior to conversion of the subsequent analog signal to a subsequent digital signal in response to the comparison between the previous digital signal and the normalized range; and replacing the previous digital signal by the subsequent digital signal in memory until each digital signal in memory is within the normalized range and updating the amplification of each subsequent analog signal until the corresponding digital signals are within the normalized range.