Abstract: The present invention relates to a resistive touchscreen for recognizing touch coordinates through a capacitor charging time constant, and more specifically, the invention comprises: an equal resistance line operating means for obtaining the same resistance line according to an (Rv+Ry+) value and the same resistance line according to an (Rv+Ry?) value by using the charge time constant after a charge time constant measuring means measures charge time constants of capacitors CconL and CconR; and a coordinate calculating means for obtaining intersecting points of the resistance lines, thereby perceiving the intersecting points as touch positions. According to the present invention, a conventional ADC (analog to digital converter) is not used because the touch positions can be perceived through the capacitor charging time constants, whereby the invention is advantageous for IC integration.

Abstract: The present invention relates to a resistive touchscreen for recognizing touch coordinates through a capacitor charging time constant, and more specifically, the invention comprises: an equal resistance line operating means for obtaining the same resistance line according to an (Rv+Ry+) value and the same resistance line according to an (Rv+Ry?) value by using the charge time constant after a charge time constant measuring means measures charge time constants of capacitors CconL and CconR; and a coordinate calculating means for obtaining intersecting points of the resistance lines, thereby perceiving the intersecting points as touch positions. According to the present invention, a conventional ADC (analog to digital converter) is not used because the touch positions can be perceived through the capacitor charging time constants, whereby the invention is advantageous for IC integration.

Abstract: Disclosed herein is a method for detecting capacitance including: allowing an oscillator to output a plurality of time division oscillation frequencies according to the capacitance detected by a capacitance detection plate; counting the plurality of time division oscillation frequencies during a predetermined time period; and offsetting increasing and decreasing of the oscillation frequencies due to noise such that a count value becomes uniform over the predetermined time period. Even when external noise is applied, distortion of the oscillation frequency due to the external noise is minimized and the oscillation frequency varies depending on only the capacitance of the capacitance detection plate. Accordingly, it is possible to prevent an error due to the noise at the time of the detection of the capacitance.

Abstract: Disclosed herein is a method for detecting capacitance including: allowing an oscillator to output a plurality of time division oscillation frequencies according to the capacitance detected by a capacitance detection plate; counting the plurality of time division oscillation frequencies during a predetermined time period; and offsetting increasing and decreasing of the oscillation frequencies due to noise such that a count value becomes uniform over the predetermined time period. Even when external noise is applied, distortion of the oscillation frequency due to the external noise is minimized and the oscillation frequency varies depending on only the capacitance of the capacitance detection plate. Accordingly, it is possible to prevent an error due to the noise at the time of the detection of the capacitance.

Abstract: Disclosed herein is a character input apparatus including a keypad with a reference key and a plurality of peripheral keys surrounding the reference key, and a recognition device which recognizes characters respectively applied to the reference key and the peripheral keys to be inputted if the reference key and the peripheral keys are respectively pressed so as to perform pressing inputs and recognizes character respectively applied to directions to be inputted if the peripheral keys are respectively pressed while the reference key is pressed so as to perform directional inputs. Accordingly, it is possible to improve convenience in character input and increasing a character input speed, by reducing the number of times of pressing of keys and eliminating input inconvenience due to a “pause” function using a directional input and a U-turn reverse direction input.

Abstract: A method and an integrated circuit for detecting capacitance variation includes the steps of: generating a detection frequency for capacitance variation and a detection frequency which lags the detection frequency by k times, wherein the detection frequencies are based on a time divisional format; operating the detection frequencies to produce a difference frequency; operating variation rate of the difference frequency; and comparing the variation rate of the difference frequency with a predetermined detection level, and outputting a signal indicative of capacitance variation if the variation rate of the difference frequency is greater than the detection level.

Abstract: A method and an integrated circuit (IC) for detecting capacitance variation are disclosed. In order to resolve the prior art problem that sensitivity of detecting capacitance variation is decreased by a time delay component td of a charging/discharging unit, the present invention employs two time divided frequencies.