Touch-type input device

• US 10,061,433 B2
• Filed: 06/17/2015
• Issued: 08/28/2018
• Est. Priority Date: 06/26/2014
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Tokai RIKA Denki Seisakusho, SMK Corporation
• Original Assignee: Kabushiki Kaisha Tokai RIKA Denki Seisakusho, SMK Corporation
• Inventors: Imai, Takao, Takai, Yuji, Yoshikawa, Osamu
• Primary Examiner(s): Lee, Nicholas
• Assistant Examiner(s): STONE, ROBERT M
• Application Number:
  US15/315,580
• Publication Number:
  US 20170075482A1
• Time in Patent Office: 1,168 Days
• CPC Class Codes: B60K 2360/1438 Touch screens
• CPC Class Codes: B60K 2360/774 on or in the centre console
• CPC Class Codes: B60K 35/10 Input arrangements, i.e. from user to vehicle, associated with vehicle functions or specially adapted therefor
• CPC Class Codes: B60K 35/60 Instruments characterised by their location or relative disposition in or on vehicles arrangements of lighting devices on dashboards B60Q3/10
• CPC Class Codes: B60K 35/90 Calibration of instruments, e.g. setting initial or reference parameters; Testing of instruments, e.g. detecting malfunction
• CPC Class Codes: G06F 3/041 Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
• CPC Class Codes: G06F 3/04186 Touch location disambiguation
• 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 touch-type input device includes a touch panel in which drive electrodes and sensor electrodes are arranged in a grid pattern that provide capacitors. The touch-type input device also includes a controller that determines whether or not there is a touch based on data values that each indicate an amount of change in capacitance of each capacitor from a predetermined reference value. The controller sets the reference value by obtaining a parasitic capacitance of each capacitor when the touch-type input device is activated. When determining from a variation range of the parasitic capacitances of the capacitors that an erroneous reference value has been obtained, the controller re-obtains a parasitic capacitance.

Claims

1. A touch-type input device comprising:

a touch panel including a sensor array and an operation surface, wherein the sensor array includes drive electrodes and sensor electrodes overlapped with and insulated from the drive electrodes, and the drive electrodes and the sensor electrodes are arranged in a grid pattern that forms capacitors at intersections of the drive electrodes and the sensor electrodes; and

a controller that applies a drive signal to the drive electrodes to detect touching of the operation surface of the touch panel from changes in capacitance of each capacitor, wherein

the controller is configured to;

determine whether or not there is a touch based on data values that each indicate an amount of change in capacitance of each capacitor from a predetermined reference value;

obtain initial reference values for the capacitors by detecting a parasitic capacitance of each capacitor when the touch-type input device is activated, wherein the controller determines an initial variation range from a difference between a maximum value and a minimum value of the initial references values and sets a determination range having a smaller range than the initial variation range by multiplying the initial variation range by a predetermined proportion;

re-obtain new reference values for the capacitors by detecting a parasitic capacitance of each capacitor again after the touch-type input device is activated and determine a current variation range from a difference between a maximum value and a minimum value of the new references values;

prior to determining whether or not there is a touch, determining whether or not the initial reference values are erroneous by determining whether or not the current variation range is smaller than the determination range; and

when the current variation range is smaller than the determination range, determine that the initial reference values are erroneous and use the new reference values to determine whether or not there is a touch.

2. The touch-type input device according to claim 1, wherein the controller is further configured to determine that the initial reference values are erroneous when determining that the initial variation range is larger than a predetermined specific range.

3. The touch-type input device according to claim 1, wherein the controller is further configured to determine that the initial reference values are erroneous when determining that at least one of the parasitic capacitances of the capacitors is larger than a predetermined specific range.