Display-integrated type tablet device

• US 5,442,373 A
• Filed: 05/19/1993
• Issued: 08/15/1995
• Est. Priority Date: 05/22/1992
• Status: Expired due to Term

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Nomura, Toshio, Kako, Noritoshi, Tagawa, Takao
• Primary Examiner(s): Hjerpe, Richard
• Assistant Examiner(s): CHIN, VIVIAN C
• Application Number:
  US08/065,882
• Time in Patent Office: 818 Days
• Field of Search: 345/178, 345/179, 345/182, 345/174, 345/104, 345/173, 178/19
• US Class Current: 345/104
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• CPC Class Codes: G06F 3/04184 Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally
• CPC Class Codes: G06F 3/0441 using active external devices, e.g. active pens, for receiving changes in electrical potential transmitted by the digitiser, e.g. tablet driving signals

Abstract

Displacement between an actual designation position designated by a detection pen and a detection coordinates is corrected. A correction calculation section includes a plurality of processing mode determination modules, a propagation delay correction module, an inward displacement correction module, a waveform distortion correction module, and a periodical fluctuation correction module. The processing mode determination module determines a correction module according to a detection coordinate value input. Each of the correction modules includes a correction formula or a lookup table inherent to each area. According to the correction formula or the lookup table, input detection coordinate value is corrected to thereby correct the displacement between the actual designation position and the detection coordinate value.

Claims

1. A display-integrated type table device including a display panel driven by first electrodes and second electrodes crossing each other at right angles, a detection pen having at a tip thereof an electrode which can be electrostatically coupled with the first electrodes and the second electrodes, a first electrode drive circuit for driving the first electrodes, a second electrode drive circuit for driving the second electrodes, a display control circuit for displaying an image on the display panel by controlling the first electrode drive circuit and the second electrode drive circuit in an image display period, a detection control circuit for sequentially scanning at least one of the first and second electrodes of the display panel by controlling at least one of the first and second drive circuits in a coordinate detection period, and a coordinate detection circuit for detecting at least one of a detection x-coordinate value and a detection y-coordinate value on the display panel designated by the tip of the detection pen based on a time of generating an output signal from the detection pen and a time of scanning at least one of the first and second electrodes,

the display-integrated type table device comprising a correction processing circuit which has an inward displacement correction module for correcting an inward displacement of at least one of the detection x-coordinate value and the detection y-coordinate value attributed to a reduction in number of at least one of the first electrodes and the second electrodes to which a scanning pulse is applied.