Touched position detection method for touch panel

• US 8,542,213 B2
• Filed: 07/02/2009
• Issued: 09/24/2013
• Est. Priority Date: 09/08/2008
• Status: Active Grant

• Current Assignee: Paneltouch Technologies LLC
• Original Assignee: Hitachi Displays Limited (Japan Display Incorporated), Panasonic Liquid Crystal Display Company Limited (Panasonic Holdings Corporation)
• Inventors: Doi, Koji, Mamba, Norio, Nagata, Koji, Kumagai, Toshiyuki, Hayakawa, Koji, Atsuta, Toshiaki
• Primary Examiner(s): Nguyen, Chanh
• Assistant Examiner(s): NOKHAM, JAMES S
• Application Number:
  US12/496,804
• Publication Number:
  US 20100060609A1
• Time in Patent Office: 1,545 Days
• Field of Search: 345/156, 345/173, 345/174, 345/177, 178/18.06, 324/686
• US Class Current: 345/174
• 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

In a touched position detection method for a touch panel for detecting a touched position, based on measured values by a plurality of sensors, presence of a touch is determined when a measured value by a sensor exceeds a touch threshold. As a touch threshold, a value which cannot be attained due to a mere noise but can due to presence of a touch is set. With respect to sensors located in the vicinity of a sensor showing a high measured value, a higher weighted value is applied to modify a measured value in a touched position calculation process than that to be applied to other sensors.

Claims

1. A touched position detection method for a touch panel for detecting a touched position, based on measured values by a plurality of sensors, comprising:

a step of selecting sensors located in a vicinity of a sensor showing a measured value higher than a predetermined level; and

a step of applying a first noise reduction parameter to measured values by the selected sensors and applying a second noise reduction parameter which is different from the first noise reduction parameter to measured values by other sensors having a measured value lower than the measured value of the selected sensors,

wherein the first and second noise reduction parameters are respectively predetermined values to be subtracted from a measured value by a sensor to be referred to in a touched position calculation process.

2. The touched position detection method for a touch panel according to claim 1, wherein

the sensors are electrodes of which static capacitance is able to be measured, and

the measured values are values indicating static capacitance.

3. The touched position detection method for a touch panel according to claim 1, wherein the selected sensors are a set of sensors located within a predetermined distance from the sensor showing a high measured value.

4. A touched position detection method for a touch panel for detecting a touched position, based on current measured values by sensors and reference values which are measured values by sensors with absence of a touch, comprising:

a step of selecting sensors located in a vicinity of a sensor showing a measured value higher than a predetermined level, wherein content of an update process for updating the reference values is controlled depending on whether or not sensors of concern are included in the selected sensors and,

a step of applying a first noise reduction parameter to measured values by the selected sensors and applying a second noise reduction parameter which is different from the first noise reduction parameter to measured values by other sensors having a measured value lower than the measured value of the selected sensors,

wherein the first and second noise reduction parameters are respectively predetermined values to be subtracted from a measured value by a sensor to be referred to in a touched position calculation process.

5. The touched position detection method for a touch panel according to claim 4, wherein

the sensors are electrodes of which static capacitance is able to be measured, and

the measured values are values indicating static capacitance.

6. The touched position detection method for a touch panel according to claim 4, wherein the selected sensors are a set of sensors located within a predetermined distance from the sensor showing a measured value higher than a predetermined level.