Patent Application
20140152607
1. Field of the Invention
The present invention relates to proximity sensing technology, and more particularly, to a touch-sensing device using self-sensing signals to implement a proximity detection function and related proximity detection method thereof.
2. Description of the Prior Art
With the advance of science and technology, consumer electronic products, such as personal digital assistants (PDA) and mobile phones, have exploited widespread use of touch panels as their operational interfaces/user interfaces. However, a mobile phone with a touch display is prone to making inadvertent dials when a user holds the mobile phone near his/her face. A common solution is to make use of a proximity sensor to detect whether someone's face (or other objects) is near a touch-sensitive electronic product. The proximity sensor is usually implemented by an infrared LED emitter and receiver pair, or by an extra metal/ITO sensor. If there is an object approaching the touch-sensitive electronic product being detected, the touch-sensitive electronic product will turn off the touch display or the touch control functionality.
However, an additional proximity sensor will increase the product cost. Therefore, there is a need for a touch-sensing device having a proximity detection function without using additional proximity sensors.
In accordance with exemplary embodiments of the present invention, a touch-sensing device using self-sensing signals to implement a proximity detection function and related proximity detection method thereof are proposed to solve the above-mentioned problem.
According to an aspect of the present invention, an exemplary touch-sensing device with a proximity detection function is disclosed. The exemplary touch-sensing device includes a capacitive touch panel and a control circuit. The capacitive touch panel is arranged for generating a plurality of self-sensing signals via a plurality of traces, respectively. The control circuit is coupled to the capacitive touch panel, and arranged for receiving the plurality of self-sensing signals from the capacitive touch panel, and determining whether there is an object approaching the capacitive touch panel according to the plurality of self-sensing signals.
According to another aspect of the present invention, an exemplary touch-sensing method is disclosed. The exemplary proximity detection method includes receiving a plurality of self-sensing signals from a capacitive touch panel; and determining whether there is an object approaching the capacitive touch panel according to the plurality of self-sensing signals.
These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings.
Certain terms are used throughout the description and following claims to refer to particular components. As one skilled in the art will appreciate, manufacturers may refer to a component by different names. This document does not intend to distinguish between components that differ in name but not function. In the following description and in the claims, the terms “include” and “comprise” are used in an open-ended fashion, and thus should be interpreted to mean “include, but not limited to . . . ”. Also, the term “couple” is intended to mean either an indirect or direct electrical connection. Accordingly, if one device is electrically coupled to another device, that connection may be through a direct electrical connection, or through an indirect electrical connection via other devices and connections.
Please refer to
In this embodiment, the capacitive touch panel 120 includes a plurality of traces H1-HN and V1-VM. The traces H1-HN are arranged and aligned in a first direction X, while the traces V1-VM are arranged and aligned in a second direction Y. The first direction X and the second direction Y are not parallel. For example, the first direction X is perpendicular to the second direction Y. The traces H1-HN and the traces V1-VM are intersected with one another. However, the traces H1-HN and the traces V1-VM are not coplanar. In this way, each of the traces H1-HN will not directly contact with any of the traces V1-VM, and vice versa. Under this configuration, each of the plurality of traces H1-HN and V1-VM serves as an independent self-capacitance sensor, and therefore the plurality of traces H1-HN and V1-VM are utilized for generating a plurality of self-sensing signals S1-SM+N, respectively. Please note that the plurality of traces H1-HN and V1-VM may be aligned in a bar-pattern or a diamond-pattern. However, it is for illustrative purpose only and not meant to be a limitation of the present invention.
In addition, the control circuit 140 is coupled to the capacitive touch panel 120. The control circuit 140 includes, but not limited to, a receiving unit 142, a processing unit 144 and a determining unit 146. The receiving unit 142 is arranged for receiving the self-sensing signals S1-SM+N from the capacitive touch panel 120. The processing unit 144 is coupled to the receiving unit 142, and arranged for generating a sensing value SV according to the self-sensing signals S1-SM+N. The determining unit 146 is coupled to the processing unit 144, and arranged for comparing the sensing value SV with a predetermined threshold TH to determine whether there is an object approaching the capacitive touch panel 120.
Please note that, since the plurality of traces H1-HN and V1-VM are substantially capacitors, magnitude of the self-sensing signals S1-SM+N generated due to approaching of the object OB (e.g., a user's face) is inversely proportional to the square of the distance between the object OB (e.g., a user's face) and the capacitive touch panel 120. That is, the self-sensing signals S1-SM+N obtained at the time the object OB (e.g., a user's face) touches the capacitive touch panel 120 will be significantly larger than that obtained at the time the object OB (e.g., a user's face) only approaches the capacitive touch panel 120. In other words, it is engineered that the self-sensing signals S1-SM+N are significant only when the object OB (e.g., a user's face) actually touches the capacitive touch panel 120.
Therefore, in order to obtain a distinguishable result from the insignificant self-sensing signals S1-SM+N when the object OB (e.g., a user's face) approaches but not actually touches the capacitive touch panel 120, the control circuit 140 generates the sensing value SV corresponding to a summation of the plurality of self-sensing signals S1-SM+N, and compares the sensing value SV with the predetermined threshold TH to determine whether the object OB (e.g., a user's face) approaches the capacitive touch panel 120. Please refer to
Besides, when the control circuit 140 determines the object OB (e.g., a user's face) approaches the capacitive touch panel 120, the touch-sensing device 100 may turn off a backlight of the touch-sensing device 100 to conserve power consumption and/or temporarily disable the touch-sensing function to avoid inadvertent touch operations.
Please refer to
Step 300: Start.
Step 301: Receive the plurality of self-sensing signals S1-SM+N from the capacitive touch panel 120.
Step 302: Determine whether there is an object approaching the capacitive touch panel 120 according to the plurality of self-sensing signals S1-SM+N.
Step 303: End.
The proximity detection method illustrates the operations of the touch-sensing device 100. As details of each step in
To sum up, the present invention provides a proximity detection function implemented by using a capacitive touch panel. Hence, the proposed proximity detection design may be applied to a variety of applications without raising additional hardware costs.
Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.
