Control circuit of electrostatic capacitive sensor and electronic device using the same

• US 9,838,527 B2
• Filed: 05/18/2016
• Issued: 12/05/2017
• Est. Priority Date: 03/19/2012
• Status: Expired due to Fees

• Current Assignee: ROHM Co., Ltd.
• Original Assignee: ROHM Co., Ltd.
• Inventors: Oishi, Yuki, Yamashiro, Yo
• Primary Examiner(s): Yang, Kwang-Su
• Application Number:
  US15/157,689
• Publication Number:
  US 20160269541A1
• Time in Patent Office: 566 Days
• Field of Search: 345173, 345174
• CPC Class Codes: G06F 2203/04108 Touchless 2D- digitiser, i.e. digitiser detecting the X/Y position of the input means, finger or stylus, also when it does not touch, but is proximate to the digitiser's interaction surface without distance measurement in the Z direction
• CPC Class Codes: G06F 3/04166 Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally G06F3/04184
• 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
• CPC Class Codes: H04M 1/0266 for a display module assembly
• CPC Class Codes: H04M 1/23 Construction or mounting of dials or of equivalent devices; Means for facilitating the use thereof by improving visibility H04M1/22
• CPC Class Codes: H04M 1/72454 according to context-related or environment-related conditions
• CPC Class Codes: H04M 2250/12 including a sensor for measuring a physical value, e.g. temperature or motion telephones including GPS signal receivers H04M2250/10
• CPC Class Codes: H04M 2250/22 including a touch pad, a touch sensor or a touch detector digitizers for touch screens G06F3/041

Abstract

An electrostatic capacitive sensor includes a plurality of transmitter electrodes, a plurality of receiver electrodes, and a control circuit. Further, the control circuit includes: a transmitter circuit configured to apply a periodical transmission signal to each of the plurality of transmitter electrodes; and a receiver circuit configured to generate, based on a reception signal generated in each of the plurality of receiver electrodes in response to the transmission signal, a detection signal indicating a change in electrostatic capacitance formed at each of intersections of the plurality of transmitter electrodes and the plurality of receiver electrodes, wherein the transmitter circuit is configured to switch between a first mode where the transmission signal is sequentially applied to the plurality of transmitter electrodes and a second mode where the plurality of transmitter electrodes are grouped and the same transmission signal is applied to a plurality of transmitter electrodes belonging to the same group.

Claims

1. An electronic equipment comprising:

a housing;

a display panel disposed on one surface of the housing;

an electrostatic capacitive sensor disposed at an overlapping portion of the housing with the display panel, the electrostatic capacitive sensor including a plurality of transmitter electrodes disposed in parallel in a first direction and a plurality of receiver electrodes disposed in parallel in a second direction, and spaced apart from the plurality of transmitter electrodes by specific intervals;

a control circuit disposed within the housing and configured to detect a change in capacitance of the electrostatic capacitive sensor, and including;

a transmitter circuit configured to apply a periodical transmission signal to each of the plurality of transmitter electrodes; and

a receiver circuit configured to generate, based on a reception signal generated in each of the plurality of receiver electrodes in response to the transmission signal, a detection signal indicating a change in electrostatic capacitance formed at each of intersections of the plurality of transmitter electrodes and the plurality of receiver electrodes,

wherein the transmitter circuit is configured to switch between a first mode, where the transmission signal is sequentially applied to the plurality of transmitter electrodes, and a second mode, where the plurality of transmitter electrodes are grouped and the same transmission signal is applied to a plurality of transmitter electrodes belonging to the same group; and

a processor configured to receive a digital value corresponding to the detection signal generated by the receiver circuit of the control circuit and configured to detect a manipulation status of the electronic equipment by a user based on the digital value,

wherein the processor refers to the digital value obtained in the second mode and determines that a user grips the housing if a change in capacitance of the transmitter and the receiver electrodes disposed at one end of the housing to which the user'"'"'s thumb approaches when the housing is gripped by the user and the transmitter and the receiver electrodes disposed at the other end of the housing to which the other fingers approach increase, and

wherein at least one of the transmitter circuit and the receiver circuit is set to the second mode in order to have a spatial resolution in a short side direction between the first direction and the second direction of the housing.

2. The electronic equipment of claim 1, wherein a grip condition is determined when a change in capacitance in both ends at the vicinity of the lower and upper limits of coordinates in the short side direction is large.

3. The electronic equipment of claim 1, wherein a grip condition is determined by comparing a digital value having the spatial resolution in the short side direction with a predetermined pattern.