Detection device and display apparatus with oscillation control

• US 8,890,836 B2
• Filed: 06/16/2011
• Issued: 11/18/2014
• Est. Priority Date: 07/09/2010
• Status: Expired due to Fees

• Current Assignee: Japan Display Incorporated
• Original Assignee: Japan Display West Incorporated (Japan Display Incorporated)
• Inventors: Mizuhashi, Hiroshi, Azumi, Kohei, Yamaguchi, Kazunori, Nakanishi, Takayuki
• Primary Examiner(s): Yang, Kwang-Su
• Application Number:
  US13/067,637
• Publication Number:
  US 20120007828A1
• Time in Patent Office: 1,251 Days
• Field of Search: 345/173, 345/174
• US Class Current: 345/174
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/0445 using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer
• CPC Class Codes: G06F 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes

Abstract

A detection device includes a sensor unit in which a plurality of detection electrodes is positioned in a detection surface, a selection unit that selects one of the plurality of detection electrodes or a plurality of detection electrodes, an oscillation unit in which an oscillation frequency is determined by a capacitance generated in the one or plurality of detection electrodes selected by the selection unit, a conversion unit that outputs a signal corresponding to the frequency of a signal from the oscillation unit, and a switch unit that performs electrical connection/disconnection between a wiring for connecting the oscillation unit and the selection unit and a constant voltage line.

Claims

1. A detection device, comprising:

a sensor unit in which detection electrodes are positioned in a detection surface;

a selection unit that selects one or more of the detection electrodes;

an oscillation unit in which an oscillation frequency is determined by a capacitance generated in the one or more detection electrodes selected by the selection unit;

a conversion unit that outputs a signal corresponding to the frequency of a signal from the oscillation unit; and

a switch unit that performs an electrical connection/disconnection between a wiring for connecting the oscillation unit and the selection unit and a constant voltage line, wherein

the oscillation unit changes a state between being enabled and disabled,

the detection device further comprises a control unit that disables and enables the oscillation unit and controls the switch unit while the selection unit selects the one or more detection electrodes, and connects the one or more detection electrodes selected by the selection unit to the constant voltage line, and

while the selection unit selects the one or more detection electrodes,

the control unit disables the oscillation unit and connects the one or more detection electrodes selected by the selection unit to the constant voltage line by controlling the switch unit to discharge charges accumulated in the one or more detection electrodes selected by the selection unit immediately before enabling the oscillation unit, and

after the discharging, the control unit disconnects the one or more detection electrodes selected by the selection unit from the constant voltage line by controlling the switch unit, and enables the oscillation unit.

2. A display apparatus, comprising:

a display panel that displays an image on a display surface based on an image signal;

a sensor unit in which detection electrodes are disposed on the display surface;

a selection unit that selects one or more of the detection electrodes;

an oscillation unit in which an oscillation frequency is determined by a capacitance generated in the one or more detection electrodes selected by the selection unit;

a conversion unit that outputs a signal corresponding to the frequency of a signal from the oscillation unit; and

a switch unit that performs an electrical connection/disconnection between a wiring for connecting the oscillation unit and the selection unit and a constant voltage line, wherein

the oscillation unit changes a state between being enabled and disabled,

the display apparatus further comprises a control unit that disables and enables the oscillation unit and controls the switch unit while the selection unit selects the one or more detection electrodes, and connects the one or more detection electrodes selected by the selection unit to the constant voltage line, and

while the selection unit selects the one or more of detection electrodes,

the control unit disables the oscillation unit and connects the one or more detection electrodes selected by the selection unit to the constant voltage line by controlling the switch unit to discharge charges accumulated in the one or more detection electrodes selected by the selection unit immediately before enabling the oscillation unit, and

after the discharging, the control unit disconnects the one or more detection electrodes selected by the selection unit from the constant voltage line by controlling the switch unit, and enables the oscillation unit.