Patent Application
20120176326
1. Field of the Invention The present invention relates to a control device for a touch panel and a signal processing method thereof.
2. Description of the Related Art
Touch panels are widely applied in a variety of fields such as home appliances, communication devices and electronic information devices. The touch panel is often applied in input interfaces of personal digital assistants (PDAs), electronic products and game consoles. The current trend of integrating a touch panel and a display allows a user to select an icon displayed on the panel by using a finger or a touch pen, so that the PDA, the electronic product, or the game console executes a desired is function. The touch panel may also be applied in a public information inquiry system, so that the user can operate the system more efficiently.
The control device 100 includes a selection module 14, an analog to digital conversion circuit 16, and a processing unit 18. The selection module 24 couples with the touch panel 12 and selects the sensing lines L1 to Ln from the X-directional sensing lines X1 to Xm and the Y-directional sensing lines Y1 to Yn. The analog to digital conversion circuit 16 converts the voltages of the sensing lines L1 to Ln to an n-bit digital signal. The n-bit digital signal represents the touching condition of the sensing lines to be measured. The processing unit 18 receives the n-bit digital signal converted by the analog to digital conversion circuit 16 and figures out the touching condition of the sensing lines through an algorithm. The touching condition includes data of the touching position and the touching area of the touching tool.
However, the signal received by the processing unit 18 may be a clear touching signal or a signal with noise. Thus, the processing unit 18 requires a complex filter for removing the noise. In order to simplify the is internal circuitry of the processing unit 18 and to provide an efficient digital signal, it is necessary to provide a control device for a touch panel and a signal processing method thereof to filter the noise from the output data.
The present invention discloses a control device for a touch panel. The touch panel comprises a plurality of X-directional sensing lines and a plurality of Y-directional sensing lines. The X-directional sensing lines and the Y-directional sensing lines are arranged in a staggered manner. The control device of the present invention comprises a selection module, an analog to digital conversion circuit, and a control unit. The selection module selects the sensing lines to be measured from the X-directional sensing lines and the Y-directional sensing lines. The analog to digital conversion circuit couples with the selection module for receiving voltages of the sensing lines to be measured. In accordance with different operation modes, the analog to digital conversion circuit converts the voltages into different bits of a sequence digital signal. When the analog to digital conversion circuit operates in a normal mode, the analog to digital conversion circuit outputs an n-bit digital signal. When the analog to digital conversion circuit operates in a detecting mode, the analog to digital conversion circuit outputs an m-bit digital signal, wherein n>m. The control unit is configured for controlling the analog to digital conversion circuit to operate either in the normal mode or in the detecting mode.
The present invention also discloses a signal processing method for a touch panel. The signal processing method of the present invention comprises the following steps: selecting a plurality of sensing lines to be measured from the X-directional sensing lines and the Y-directional sensing lines; determining a threshold value and a bit number m to be measured; converting voltages of the sensing lines to be measured in accordance with the m-bit and outputting an m-bit digital signal; detecting the converted m-bit digital signal and a difference between the m-bit digital is signal and a predetermined m-bit digital signal, when the converted m-bit digital signal and the predetermined m-bit digital signal have the same value to accumulate a counting value; and converting voltages of the sensing lines to be measured to an n-bit digital signal when the counting value is greater than or equal to the threshold value, wherein n>m.
The foregoing has outlined rather broadly the features and technical benefits of the disclosure in order that the detailed description of the invention that follows may be better understood. Additional features and benefits of the invention will be described hereinafter, and form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures or processes for carrying out the same purposes of the disclosure. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims.
The invention will be described according to the appended drawings in which:
The present invention is directed to a control device and a signal is processing method for a touch panel. In order to make the present invention completely comprehensible, detailed steps and structures are provided in the following description. Obviously, implementation of the present invention does not limit special details known by persons skilled in the art. In addition, known structures and steps are not described in detail, so as not to unnecessarily limit the present invention. Preferred embodiments of the present invention will be described below in detail. However, in addition to the detailed description, the present invention may also be widely implemented in other embodiments. The scope of the present invention is not limited to the detailed description, and is defined by the claims.
is Referring
As shown in
The operation mode of the analog to digital conversion circuit 26 is controlled by a control unit 28.
In one embodiment of the present invention, the touch input device 20 is operated as illustrated in
is In the present embodiment, the 2-bit digital signals D7,1 and D6,1 will be recorded in the first register 281. Consequently, the analog to digital conversion circuit 26 continuously converts the voltages of the sensing lines X3 and X4 to 2-bit digital signals D 7, 2 and D 6, 2 . Since the noise interferes with the signal, the value of the digital signals D7,2 and D6,2 is different from that of the digital signals D7,1 and D6,1. Thus, after the detecting unit 282 compares the digital signals D7,2 and D6,2 with digital signals D7 ,1 and D 6 , 1 , the detecting unit 282 will generate a comparing signal (cmp) with a low level. The counter 286 is not activated in accordance with the low-level comparing signal (cmp).
The analog to digital conversion circuit 26 continuously converts the voltages of the sensing lines X3 and X4 to 2-bit digital signals D7,3 and D 6,3. Since the value of the digital signals D7,3 and D6,3 is the same as that of the digital signals D7,1 and D6,1, the detecting unit 282 will generate a comparing signal (cmp) with a high level. The counter 286 will accumulate a counting value in accordance with the high-level comparing signal (cmp).
Similarly, the analog to digital conversion circuit 26 continuously converts the voltages of the sensing lines X3 and X4. After the detecting unit 282 compares the converted digital signals with the digital signals D7,1 and D6,1, the level of the comparing signal (cmp) is continuously updated. The comparing unit 288 determines whether the counting value (CNT) is accumulated in accordance with the level of the comparing signal (cmp). When the counting value (CNT) is greater than or equal to the threshold value (e.g. 3) registered by the second register 282, the comparing D) unit 286 transmits a control signal (CTL) to switch the analog to digital conversion circuit 26 to operate in the normal mode from the detecting mode. Therefore, the analog to digital conversion circuit 26 will continuously convert the voltages of the sensing lines X 3 and X4 to a 2-bit digital signal. The entire 8-bit digital signal D0 to D7 will be transmitted is to the processing unit 30 for further processing. Since the control device 200 of the present invention can adjust the outputted bit number of the analog to digital conversion circuit 26 and the threshold value, the present invention can effectively remove the noise and ensure the signals received by the processing unit 30 to be clear touch signals.
Although the present disclosure and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the disclosure as defined by the appended claims. For example, many of the processes discussed above can be implemented in different methodologies and replaced by other processes, or a combination thereof.
Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, and composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present disclosure, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed, that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present disclosure. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.
| Number | Date | Country | Kind |
|---|---|---|---|
| 100100582 | Jan 2011 | TW | national |
