1. Field of the Invention
This invention relates to an optical sensing screen and a panel sensing method for selectively sensing an object and a light pen, and more particularly to the optical sensing screen and the panel sensing method which can be used to be passively inputted with fingers of a user or be actively inputted with a light pen particularly designed.
2. Description of the Related Art
With the advances of technology, electronic products have more functions. People can enter the necessary information into their electronic products with various kinds of input apparatuses (e.g., a keyboard, a mouse, etc.) by different kinds of input methods. To comply with people's requirements to input data quickly and conveniently, the input methods and the modules of electronic products nowadays are getting more diverse, and a touch panel is one of the major technologies. Since users can operate touch panels by inputting with their hands intuitively, more and more electronic products have adopted touch panels as the operating interfaces, so that the requirement of touch panels increases greatly.
In early times, the touch panels in Tablet PCs almost adopted the Electro-Magnetic touch technique of Wacom's company. The touch panel has active electro-magnetic sensor in the liquid crystal module, a pen in which a coil is placed is used to input information. However, the technique can only detect the signal from the pen with the coil, but it cannot be operated by fingers. The resistive module or the surface capacitive module can provide Tablet PCs the function of inputting by touching the panel with fingers.
A resistive touch panel is consisted of an ITO Film, an ITO Glass, and a DOT between the ITO Film and the ITO Glass. By inputting 5V voltage between the ITO Film and ITO Glass, touching the ITO Film to form a hollow by the fingers or a touch pen, generating the variation of the voltage by touching the lower ITO Glass, and transforming the variation of the voltage into digital signals through an A/D controller for a computer to get the coordinates of the X and Y, the goal of positioning can be achieved. The resistive touch panel can be classified into four-wire resistive touch panels and five-wire resistive touch panels according to functions and popularity. The X and Y axis of the four-wire resistive touch panels are distributed at the ITO Film and ITO Glass respectively. When the ITO Film is seriously scraped, the touch panel will not work due to the broken circuit. The five wires resistive touch panels are improved from the four wires resistive touch panels to form a uniform electronic filed on the ITO Glass. The upper ITO Film is a conductor, so the ITO Film can not work just at the position which is scraped and other parts can still be used. But if the lower ITO Glass is damaged, the touch panel still won't work.
Capacitive touch technique is developed 20 years ago, and the 3M Company monopolized the international market of capacitive touch panels in earlier days. In recent years, since the basic patent expired, manufacturers worldwide all joined the field of the capacitive touch panels. The capacitive touch panel improves the feature of the resistive touch panel that poor endurance of being scraped. The outer layer is a thin SiO2 hardening layer, and the hardness is 7H. The second layer is ITO, and a uniform electronic filed is formed on the glass surface. The working principle is to sense a weak current of a body to achieve the goal of touching. The lowest ITO layer is used to cover and keep the touch panel to work at the prefect environment without interference.
However, no matter it is the resistive or capacitive touch panel, the palm is always put on the screen when the user is writing. Since the movements of the palm and the finger will be sensed at the same time, the sensor can not detect correct input information.
In prior arts, U.S. Pat. No. 4,507,557 discloses a Non-contact X,Y digitizer which uses two dynamic ram imagers, and the detection object has no limitations. Any object or fingers can be detected by the technique. But the technique disclosed by the patent can not be applied to commonly inputting by hands. Since a user usually writes with the palm resting on the screen, the technique disclosed by the patent can not be used to correctly determine the position of the pen point.
Compared with prior arts, the invention provides an optical touch screen which can be used to be passively inputted with fingers of a user or be actively inputted with a light pen which is particularly designed.
A scope of the invention is to provide an optical sensing screen for selectively sensing an object and a light pen. A first photo-emitter is disposed in a light pen for emitting a first light. The optical sensing screen includes a panel, an illuminating device, at least two first photo-sensing devices and a processor. The illuminating device is disposed along the edge of the panel for forming a background light source above the panel. The first photo-sensing devices are disposed at the edge of the panel respectively for detecting the first light and the background light source. The processor is electrically connected to the illuminating device and the first photo-sensing devices respectively.
When the object obstructs the background light source, the processor calculates the coordinate of the object according to the obstructed background light source. And when any of the first photo-sensing devices detects the light pen, the processor drives the illuminating device not to form the background light source and to calculate the coordinate of the first photo-emitter according to the detected first light.
Additionally, another scope of the invention is to provide a panel sensing method which can be applied to an optical sensing screen. The optical sensing screen is capable of selectively sensing an object and a light pen. The light pen can be used for emitting a first light. The optical sensing screen includes a screen, an illuminating device, and at least two first photo-sensing devices. The illuminating device can be used for forming a background light source over the panel. The panel sensing method includes the following steps.
Compared with prior arts, the optical sensing screen of the invention utilizes the writing space formed by the first sensing device and determines whether the light pen appears in the writing space, such that the optical sensing screen can be switched between the passive touch state and the active touch state very smoothly. Therefore, the writing behavior of the user can be correctly detected while writing with the light pen and the palm or arm of the user rested on the screen simultaneously.
The advantage and spirit of the invention may be understood by the following recitations together with the appended drawings.
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To sum up, according to the optical sensing screen 1 of the invention, the operation modes includes passive touch mode and active touch mode.
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Afterwards, the light pen 28 further includes a switch 34 and a pressure sensor 32, as shown in
The foregoing three methods of switching to the active touch mode will be further explained below.
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Compared with prior arts, the optical sensing screen 1 of the invention forms the writing space by the first sensing device 14 and determines whether the light pen is in the writing space to smoothly switch the optical sensing screen 1 between the passive touch mode and the active touch mode. Therefore, the writing behavior of the user can be correctly detected while writing with the light pen and the palm or arm of the user rested on the screen simultaneously.
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The optical sensing screen 1 includes a panel 10, an illuminating device 12 and at least two first photo-sensing devices 14, wherein the illuminating device 12 can form a background light source over the panel 10. The panel sensing method includes the following steps.
Firstly, the panel sensing method according to the invention is executed to perform step S102: using the panel 10 to receive a touch.
Then, the panel sensing method according to the invention is executed to perform step S104: forming a sensing space over the panel 10.
Then, the panel sensing method according to the invention is executed to perform step S106: determining whether the light pen 28 is detected by the at least one first photo-sensing device 14.
If the answer is negative, the panel sensing method according to the invention is executed to perform step S108: making the optical sensing screen enter a passive touch mode.
If the answer is positive, the panel sensing method according to the invention is executed to perform step S114: make the optical sensing screen enter an active touch mode.
The panel sensing method according to the invention is executed to perform step S110: driving the illuminating device 12 to form the background light source, wherein the background light source can be an infrared ray.
The panel sensing method according to the invention is executed to perform step S112: calculating the coordinate of the object according to the obstructed background light source and executing step S102 again. At this time, the optical sensing screen 1 operates at the passive touch mode.
The panel sensing method according to the invention is executed to perform S116: driving the illuminating device not to form the background light source.
The panel sensing method according to the invention is executed to perform S118: calculating the coordinate of the first photo-emitters 30 according to the detected first lights and executing step S102 again. At this time, the optical sensing screen 1 operates at the active touch mode.
Compared with prior arts, the optical sensing screen of the invention utilizes the writing space formed by the first sensing device and determines whether the light pen appears in the writing space, such that the optical sensing screen can be switched between the passive touch state and the active touch state very smoothly. Therefore, the writing behavior of the user can be correctly detected while writing with the light pen and the palm or arm of the user rested on the screen simultaneously.
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 being limited only by the metes and bounds of the appended claims.
Number | Date | Country | Kind |
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098105305 | Feb 2009 | TW | national |