1. Field of the Invention
The invention relates to a touch input device and a touch sensor circuit, and more particularly to a touch input device and a touch sensor circuit capable of suppressing an EMI effect.
2. Description of the Prior Art
With the development of information technology, the electronic products become more diversified and humanized. For example, based on the touch panel or touch pad nowadays, user may simply operate the device or type some sentences with their finger or a touch pen, instead of using the mouse or keyboard to type in the traditional and inconvenient way.
There are a number of types of touch panel technology: resistive type, capacitive type, optical type and surface acoustic wave type. The resistive-typed touch panel mainly includes upper and lower ITO glass layers. When an object touches the upper ITO glass layer and presses it toward the lower ITO glass layer, the controller of the touch panel will generate a voltage signal, and coordinates of the contact point can be computed according to the voltage signal.
The capacitive-typed touch panel has two types: surface capacitive touch panel and projected capacitive touch panel. The surface capacitive touch panel includes a piece of conductive glass. Two surfaces of the conductive glass are coated with conductive material. External surfaces of the conductive glass are further coated with a protective film. The electrodes around the glass plate builds up an electric flied on the glass surfaces. When users touch the touch panel with their fingers, the fingers will be coupled to the capacitance on the glass surface and induce a small current. The controller of the touch panel may compute the coordinates of the contact point according to the current.
Recently, the projected capacitive touch panels are widely applied in various touch-input electronic devices (e.g. smart phones). The locating theory of the projected capacitive touch panel is based on the capacitive variation of the sensor grid implemented within the touch panel. Please refer to
Please refer to
In practical applications, the controller circuit 120 may control the multiplexer 12 and utilize it to select a specific X-directional conductive line (X1˜Xm) and a specific Y-directional conductive line (Y1˜Yn), so as to select one specific capacitive node. For example, the multiplexer 12 may select X-directional conductive line X3 and Y-directional conductive line Y3 for corresponding to the capacitive node 100a. Then, the detection module 14 may generate a detective pulse signal Sdet, and the detective pulse signal Sdet is imported into the capacitive node 100a through the multiplexer 12. Then, the detection module 14 judges a touch detection state of the capacitive node 100a according to the signal feedback of the detective pulse signal Sdet imported into the capacitive node 100a.
The controller circuit 120 may also control the multiplexer 12 to select one X-directional conductive line or one Y-directional conductive line in sequence, so as to scan capacitive nodes in a row/column at a time. Please refer to
This detective pulse signal Sdet is usually a voltage or current signal with high-frequency periodic pulse. When the detection module 14 imports the high-frequency detective pulse signal to a specific capacitive node (such as the capacitive node 100a), the detective pulse signal may cause the electromagnetic interference (EMI) effect to other electronic components (e.g. liquid crystal display) around the touch panel 10, and it may also cause the EMI effect to surrounding capacitive nodes (such as the capacitive nodes 100b and 100c).
Besides, in order to elevate the touch-input preciseness on the touch panel, designers are trying to narrow down the misjudging error while detecting the touch input. On the other hand, to eliminate or prevent the EMI effect between different electronic components is necessary in modern electronic products, especially in the trend of reducing the product size.
Therefore, the invention discloses a touch input device and a touch sensor circuit, which is suitable for various touch input electronic system, so as to solve said problems.
A scope of the invention is to provide a touch input device, which includes a touch panel, a selection module and a detection module.
According to an embodiment, the touch panel includes a plurality of capacitive nodes. The capacitive nodes are formed and spread on the touch panel. The selection module is electrically connected with the capacitive nodes of the touch panel. The selection module selects a first capacitive node class and a second capacitive node class from the capacitive nodes. The second capacitive node class is adjacent to the first capacitive node class. The detection module is electrically connected with the selection module. The detection module includes a signal generator used for generating a detective pulse signal. The detective pulse signal is imported into the first capacitive node class through the selection module. The detection module judges a touch detection state of the first capacitive node class according to the detective pulse signal imported into the first capacitive node class. In the meantime the signal generator generates a reversal pulse signal with a phase opposite to the detective pulse signal. The reversal pulse signal is imported into the second capacitive node class through the selection module.
Another scope of the invention is to provide a touch input device, which includes a touch panel, a selection module, a first detection module and a second detection module.
According to an embodiment, the touch panel includes a plurality of capacitive nodes. The capacitive nodes are formed and spread on the touch panel. The selection module is electrically connected with the capacitive nodes of the touch panel. The selection module selects a first capacitive node class and a second capacitive node class from the capacitive nodes. The second capacitive node class is adjacent to the first capacitive node class. The first detection module is electrically connected with the selection module. The first detection module includes a first signal generator used for generating a first detective pulse signal. The first detective pulse signal is imported into the first capacitive node class through the selection module. The first detection module judges a first touch detection state of the first capacitive node class according to the first detective pulse signal imported into the first capacitive node class. The second detection module is electrically connected with the selection module. The second detection module includes a second signal generator used for generating a second detective pulse signal. The second signal generator generates a second detective pulse signal with a phase opposite to the first detective pulse signal. The second detective pulse signal is imported into the second capacitive node class through the selection module. The second detection module judges a second touch detection state of the second capacitive node class according to the second detective pulse signal imported into the second capacitive node class.
The advantage and spirit of the invention may be understood by the following recitations together with the appended drawings.
Please refer to
In this embodiment, the touch panel 30 includes a plurality of X-directional conductive lines (X1˜Xm) and a plurality of Y-directional conductive lines (Y1˜Yn). The X-directional conductive lines and the Y-directional conductive lines are arranged in a grid shape. As shown in
As shown in
In this embodiment, the selection module 32 further includes a first multiplexer 322 and a second multiplexer 324 and a controller circuit 320 for controlling aforesaid multiplexers. The first multiplexer 322 and the second multiplexer 324 are coupled between the touch panel 30 and the detection module 34. The first multiplexer 322 and the second multiplexer 324 are electrically connected with the X-directional conductive lines (X1˜Xm) and the Y-directional conductive lines (Y1˜Yn) respectively.
The selection module 32 utilizes the controller circuit 320 for controlling the first multiplexer 322 and the second multiplexer 324 to select a first capacitive node class and a second capacitive node class from all capacitive nodes on the touch panel 30. The first capacitive node class and a second capacitive node class here may include at least one capacitive node. Besides, the second capacitive node class selected by the second multiplexer 324 is designed to be adjacent to the first capacitive node class selected by the first multiplexer 322.
To be noticed that, the first capacitive node class and a second capacitive node class here may include at least one capacitive node. In practical applications, each capacitive node class may include one capacitive node, a plurality of neighboring capacitive nodes, capacitive nodes in a row or capacitive nodes in a column.
There are three operational examples about how to select the capacitive node classes listed in following paragraphs for demonstration.
Please refer to
As shown in
As shown in
As shown in
According to aforesaid embodiments, the selection way of forming capacitive node class includes selecting vertical/parallel adjacent nodes on one or multiple conductive lines. In other words, each capacitive node class may contain singular or multiple capacitive nodes arranged in parallel-adjacent, in round shape, in rectangular shape or in any equivalent pattern.
An operational example is shown in
For example, when users makes a contact on the location of the capacitive node 300a (i.e. the first capacitive node class N1), the capacitance value of the capacitive node 300a will vary. In this case, the detection module 34 may acknowledge the touch detection state of the first capacitive node class N1, according to a signal feedback of the detective pulse signal Sdet imported to the first capacitive node class. The signal feedback corresponds to a capacitance variation of the first capacitive node class N1.
To be noticed that, while the signal generator 340 generating the detective pulse signal Sdet to the first capacitive node class N1, the signal generator 340 generates a reversal pulse signal Sinv with a phase opposite to the detective pulse signal Sdev in the meantime. In the embodiment shown in
Please refer to
In summary, the touch input device 3 generates the reversal pulse signal Sinv with the phase opposite to the detective pulse signal Sdev, and imports the reversal pulse signal Sinv to capacitive nodes around the target capacitive node class, so as to suppress the EMI effect, but the invention is not limited to this.
Please refer to
In this embodiment, the first detection module 54 and the second detection module 56 includes their own signal generators (540, 560) for generating a first detective pulse signal Sdet+ and a second detective pulse signal Sdet−. The first detective pulse signal Sdet+ is imported into the first capacitive node class through the selection module 52, for judging a first touch detection state of the first capacitive node class. On the other hand, the second detective pulse signal Sdet− is imported into the second capacitive node class through the selection module 52, for judging a second touch detection state of the second capacitive node class.
To be noticed that, the first detective pulse signal Sdet+ and the second detective pulse signal Sdet− have opposite phases. In other words, the first detective pulse signal Sdet+ and the second detective pulse signal Sdet− may suppress the EMI effect caused by the other, so as to elevate the system stability. Besides, the first detection module 54 and the second detection module 56 may judge the touch detection state of two capacitive node classes according to the first detective pulse signal Sdet+ and the second detective pulse signal Sdet− at the same time. Theoretically, the judgmental speed of touch input detection can be speeded up two times as faster as original speed in prior art. Please refer to
In the example shown in
According to aforesaid embodiments, the selection way of forming capacitive node class in the touch input device 5 of the invention is not limited to select vertical/parallel adjacent nodes. In another embodiment, each capacitive node class may contain singular or multiple capacitive nodes arranged in parallel-adjacent, in round shape, in rectangular shape or in any equivalent pattern. Besides, the total amount of capacitive nodes is not limited to two in one capacitive node class. One class may contain more than one capacitive node to achieve the equivalent or even faster detection speed. The other components and detail operational theory of the touch input device 5 in the second embodiment is substantially similar to the first embodiment, so not to be repeated here again.
Compared with prior art, the invention imports a pair of synchronic and opposite-phased pulse signal to adjacent capacitive nodes or adjacent capacitive node classes, so as to perform the touch detection. The opposite-phased pulse signals may reduce the EMI effect to other electronic components in the whole system, and elevate the stability of the touch input device.
With the example and explanations above, the features and spirits of the invention will be hopefully well described. Those skilled in the art will readily observe that numerous modifications and alterations of the device may be made while retaining the teaching of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.