Liquid crystal display having a built-in touch screen using capacitance and optical information for detecting a touch position

A liquid crystal display (LCD) with a built-in touch screen, the LCD comprising:na 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;an LCD panel comprising a liquid crystal layer interposed between the first and second substrates; anda touch screen driver circuit to sense a capacitance variation provided through a first sensing line electrically connected to the transparent electrode layer when the contact object is in contact with the LCD panel, and to output position information of the contact object, which corresponds to optical information that is produced according to external light being blocked by the contact object, and which is provided through a second sensing line electrically connected to the plurality of photosensors, when the capacitance variation is greater than or equal to a predetermined threshold value,wherein the capacitance variation is between a first capacitance of a first capacitor and a second capacitance of a second capacitor,wherein the first capacitance is formed between the contact object and the transparent electrode layer, andwherein the second capacitance is formed between the transparent electrode layer and the first substrate.

A liquid crystal display (LCD) with a built-in touch screen, the LCD comprising:na 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 transparent electrode layer;an LCD panel comprising a liquid crystal layer interposed between the first and second substrates; anda touch screen driver circuit to sense a capacitance variation provided through a first sensing line electrically connected to the transparent electrode layer when the contact object is in contact with the LCD panel, and to output position information of the contact object, which corresponds to optical information that is produced according to external light being blocked by the contact object, and which is provided through a second sensing line electrically connected to the plurality of photosensors, when the capacitance variation is greater than or equal to a predetermined threshold value,wherein the capacitance variation is between a first capacitance of a first capacitor and a second capacitance of a second capacitor,wherein the first capacitance is formed between the contact object and the transparent electrode layer, andwherein the second capacitance is formed between the transparent electrode layer and the first substrate.

A touch screen driver circuit of a liquid crystal display (LCD) with an LCD panel, a plurality of photosensors on a first substrate to sense a position of a contact object in contact with the LCD panel, and a transparent electrode layer on a second substrate, the touch screen driver circuit comprising:na controller to sense a capacitance variation provided through a first sensing line electrically connected to the transparent electrode layer when the contact object is in contact with the LCD panel; anda position sensor to output position information of the contact object, which corresponds to optical information that is produced according to external light being blocked by the contact object, and which is provided through a second sensing line electrically connected to the plurality of photosensors, when the capacitance variation is greater than or equal to a predetermined threshold value,wherein the capacitance variation is between a first capacitance of a first capacitor and a second capacitance of a second capacitor,wherein the first capacitance is formed between the contact object and the transparent electrode layer, andwherein the second capacitance is formed between the transparent electrode layer and the first substrate.