Display device

• US 7,773,068 B2
• Filed: 04/02/2007
• Issued: 08/10/2010
• Est. Priority Date: 07/24/2006
• Status: Active Grant

• Current Assignee: Japan Display Central Incorporated (Japan Display Incorporated)
• Original Assignee: Toshiba Matsushita Display Technology (Japan Display Incorporated)
• Inventors: Nakamura, Hiroki, Nakamura, Takashi, Hayashi, Hirotaka, Tada, Norio, Imai, Takayuki
• Primary Examiner(s): LEWIS, DAVID LEE
• Application Number:
  US11/695,239
• Publication Number:
  US 20080018612A1
• Time in Patent Office: 1,226 Days
• Field of Search: 345 87-102, 345173-178, 178 1801- 1811
• US Class Current: 345/104
• CPC Class Codes: G06F 3/0354 with detection of 2D relative movements between the device, or an operating part thereof, and a plane or surface, e.g. 2D mice, trackballs, pens or pucks
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes

Abstract

In order to improve accuracy in determining whether or not an object touches a display screen, a display device includes a display unit and a processor. The display unit includes an image display unit which displays an image on a display screen, an optical input unit which picks up an image of an object adjacent to the display screen and a capacitive coupling detector which detects a capacitive coupling to the object adjacent to the display screen. The processor determines that the object touches the display screen by using, and concurrently calculates the coordinates touched by the object by using the capacitive coupling detected by the capacitive coupling detector, and the image picked up by the optical input unit.

Claims

1. A display device comprising:

an array substrate including pixels, each of the pixels has a sensor capacitance element, and an amplifier which amplifies a signal based on a change in a potential difference between both sides of each of the sensor capacitance element;

an opposite substrate;

a power supply unit configured to apply a precharge voltage and a reference voltage respectively to two electrodes of the sensor capacitance element; and

a processor configured to determine that an object touches a display screen, and concurrently to calculate the coordinates touched by the object, on the basis of the signal amplified by the amplifier,

wherein the reference voltage has voltage values oscillating,

a first electrode of the two electrodes of the sensor capacitance element, which is closer to the object upon touching the display screen, has an area larger than the second electrode of the sensor capacitance element, and

between the sensor capacitance element and the object upon touching the display screen, there are not electrodes.

2. The display device according to claim 1, wherein

the precharge voltage is applied to the first electrodes, the first electrode being formed closer to the object upon touching the display screen.

3. The display device according to claim 1, wherein

one of the two electrodes, to which the precharge voltage is applied, is formed of a light transmissive material.

4. The display device according to claim 1, further comprising:

an optical sensor connected in parallel to the sensor capacitance element,

wherein the potential differences between both sides of each of the sensor capacitance element changes according to an amount of light.

5. The display device according to claim 1, wherein

the pixels include first pixels having the sensor capacitance element connected to an optical sensor in parallel and second pixels have the sensor capacitance element not connected to the optical sensor, and

the first pixels and the second pixels are arranged in a predetermined ratio.