Patent ID: 8847917
Filing Date: 2014-09-30
Classification: G06F

Abstract:
1. A liquid crystal display (LCD) with a built-in touch screen and an LCD panel, the LCD comprising: a first substrate comprising a pixel area having a plurality of pixels to display an image, and a sensor area adjacent to the pixel area and having a plurality of photosensors to sense a position of a contact object; a second substrate positioned over the first substrate, the second substrate comprising a color filter in an area corresponding to the pixel area on a first surface of the second substrate facing the first substrate, a light receiving portion, onto which external light is incident, in an area of the first surface corresponding to the sensor area, and a transparent electrode layer and a front polarizing plate sequentially stacked on a second surface of the second substrate opposite to the first surface; a liquid crystal layer interposed between the first and second substrates; and a touch screen driver circuit to measure a capacitance variation of a first capacitance between the contact object and the transparent electrode layer and a second capacitance between the transparent electrode layer and the first substrate sensed through a first sensing line connected to the transparent electrode layer and to calculate a touch area using optical information sensed through a second sensing line connected to the plurality of photosensors when the contact object is in contact with the LCD panel, and to output position information of the contact object, sensed by determining whether a touch of the contact object on the LCD panel occurs and whether a multi-touch occurs using the measured capacitance variation and the calculated touch area.