Computer graphics processing and selective visual display system – Display peripheral interface input device – Touch panel
Reexamination Certificate
2002-10-15
2004-07-13
Shalwala, Bipin (Department: 2673)
Computer graphics processing and selective visual display system
Display peripheral interface input device
Touch panel
C345S179000
Reexamination Certificate
active
06762752
ABSTRACT:
FIELD AND BACKGROUND OF THE INVENTION
The present invention relates to a digitizer and, more particularly, but not exclusively to a digitizer for accepting user input to a computing device.
Input devices typically use one of three most popular technologies, movement tracking, as in a mouse, rollerball and like devices, touch technology as in a touch screen and pointing systems as with a stylus. Different applications may be most suited to certain input technologies or systems.
Touch technologies are commonly used as input devices for a variety of products. The use of touch digitizers is growing rapidly due to the emergence of new mobile devices, such as web pads, web tablets, Tablet—PC, wireless screens and hand-held computers. Such new mobile devices usually come without any integrated keyboard or mouse, due to mobility considerations, and therefore frequently use touch input devices. As well as mobile devices, touch digitizers are useful in computer systems offering services to the general public in shops and the like, where mice are likely to be broken or removed, and are also useful for computers to be used in hazardous environments such as factory floors, since they allow the computer to be suitably sealed.
To date, touch sensitive displays have been implemented using a variety of technologies for detecting touch stimuli. In one example, a transparent overlay is placed over a display. The overlay contains an array of sensors that can be resistive, conductive or capacitive. The sensors are arranged in rows and columns spanning the display screen area; and each sensor is therefore indicative of a particular touch location. Another technology involves the processing of an optical signal scanned across a CRT screen in order to determine a touch location. Yet another technology involves an array of force sensitive transducers that are mounted around the periphery of a display. Each transducer generates a different signal upon receiving a touch stimulus. The relative magnitudes of these signals can then be used to determine a touch location. The major drawback of these technologies and others is that they are all targeted at identifying the location of a single input (e.g. a stylus, a finger). None of these solutions supports multiple inputs simultaneously.
With the emergence of Internet appliances such as Tablet PCs, the need for using a computer keyboard has become evident. Since connecting a standard keyboard to the Tablet PC diminishes the mobility of the device, the requirement to feed these devices with alphanumeric information is usually accomplished by the implementation of an “on-screen” keyboard. An “on-screen” keyboard is a scheme of a computer keyboard graphically illustrated on the display. Inputs are provided by successively touching the relevant graphical keys using a finger or a stylus. However, due to the inherent structure of existing touch technologies, it is impossible to support more than one touch (i.e. one key) at a time. This inherent property makes it impossible to apply the kind of convenient and intuitive keyboard operation known as “chord key”, for example “Shift”+“Letter” or “control”+“alt”+“delete”, at the same time.
There had been attempts in the past to combine touch sensitive input devices with other kinds of digitizer. U.S. Pat. No. 4,686,332 by Grenians, describes a combination of a capacitance finger sensible sensor with an electromagnetic stylus, both incorporated in the same transparent foil. In Grenians, the same conductors are used for measuring capacitance and for transmitting the electromagnetic signal to the pick-up stylus. However, the device is forced to switch between methods and thereby work at a vastly degraded position report rate. An additional disadvantage of Grenians is the usage of a pick-up stylus, which acts as a receiver and therefore has to be either connected to the host system by wire or alternatively must use an internal battery and transmitter. Both pick-up arrangements are undesirable for mobile systems.
U.S. Pat. No. 5,231,381 to Duwaer describes a combination of two independent sensors, one being sensitive to finger touch and the other being sensitive to stylus position, both incorporated in the same device. Duwaer's device is capable of detecting finger touch and stylus simultaneously. However, the usage of two independent input sensors is a major disadvantage since it usually raises the price of the device. Furthermore, Duwaer's device cannot detect multi finger touch and is therefore unable to support chord-key functionality.
In U.S. patent application Ser. No. 09/628,334 “Physical Object Location Apparatus and Method and a Platform using the same”, to Perski et al, an electromagnetic pointing device using a transparent conductive overlay foil is described. The device is capable of detecting the location and identity of physical objects, such as a stylus, located on top of a display. The above electromagnetic technology enables the accurate position detection of one or more electromagnetic pointers, as well as sensing of multiple physical objects, for example playing pieces for use in games. However, the electromagnetic technology is inherently unable to sense a finger touch input, and is therefore inadequate for finger-based operation of an “on-screen” or virtual keyboard. The above-mentioned application is hereby incorporated herein by reference and the reader is referred thereto wherein a method that allows simultaneous detection of different styluses or playing pieces at different positions is described.
In general, finger and stylus interactions require different detection techniques with different resolutions and different update levels. An attempt to use a single detection technique for both finger and stylus interactions is described in U.S. Pat. No. 5,543,589, to Buchana et al, which uses a four layer-two system transparent foil arrangement. Both systems use the same touch detection method but have different resolution levels and update rates so that one can sense stylus type interactions and the other can sense finger touch type interactions. A disadvantage of the system is the higher price of using two sensing systems and that the use of four foil layers markedly reduces visibility of the underlying screen when used over a display. An additional disadvantage of Buchana's system follows from the use of two similar sensing systems. Full mouse emulation, as an example, requires the tracking of the stylus position while hovering above the display. Such a feature cannot be supported by a pressure sensitive system, which is on the other hand essential for finger touch detection.
There is thus a widely recognized need for, and it would be highly advantageous to have, a digitizer devoid of the above limitations.
SUMMARY OF THE INVENTION
According to one aspect of the present invention there is provided apparatus for user input to a digital system, comprising a first sensing system having first sensors for sensing a user interaction using a sensing method of a first type, and a second sensing system having second sensors for sensing a user interaction using a sensing method of a second type, said first and second sensors being co-located on a sensing surface.
Preferably, said first and said second sensing systems respectively are operable to sense simultaneously.
Preferably, said sensing surface is superimposed on a display screen.
Preferably, said sensing surface is superimposed on a part of said display screen.
Preferably, a first of said sensing systems is superimposed on a part of said display screen, and a second of said sensing systems is superimposed substantially over an entirety of said display screen.
Preferably, each one of said sensing systems is superimposed on a respectively independently defined part of said display screen.
Preferably, said first sensing system is a touch pressure-sensing system.
Preferably, said second sensing system is an electromagnetic based sensing system.
Preferably, said display screen is a flat panel screen.
Preferably, at least one of said
Morag Meir
Perski Haim
G.E. Ehrlich (1995) Ltd.
N-trig Ltd.
Osorio Ricardo
Shalwala Bipin
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