Computer graphics processing and selective visual display system – Display peripheral interface input device – Cursor mark position control device
Reexamination Certificate
1998-03-31
2001-02-27
Saras, Steven J. (Department: 2775)
Computer graphics processing and selective visual display system
Display peripheral interface input device
Cursor mark position control device
C200S0050EA, C345S168000, C400S479000
Reexamination Certificate
active
06195082
ABSTRACT:
FIELD OF THE INVENTION
The invention generally relates to information processing systems, and more specifically, to computer pointing devices used with graphical user interfaces to information processing systems. The invention has a particular applicability to the IBM® TrackPoint® IV pointing device. (IBM and TrackPoint are registered trademarks of the International Business Machines Corporation.)
BACKGROUND OF THE INVENTION
The TrackPoint class of pointing devices employ a ceramic strain gauge balanced resistive bridge network as an isometric sensor for user input. A manipulation lever is attached to a central point on the strain gauge. Force applied to the lever causes the four resistive elements to change resistance in proportion to the amount each is distorted by the applied force. The resistances are measured and a mathematical transformation is performed to convert the changes in resistance to standard mouse-type output signals. In a specific embodiment, the output signals conform to the IBM P/S-2 computer pointing device standard. Basically, the standard mouse-type signals represent velocity in a two-dimensional space. The velocity in a given direction is proportional to the applied force in that direction. Such a pointing device is used, for example, to manipulate a graphical user interface on a computer display screen.
A prior art figure (“PRIOR ART”) illustrates the manner in which specific embodiments of the TrackPoint pointing devices are used. The manipulation lever
1
extends from a strain gauge
2
, through an opening between several keys
3
of a computer keyboard
4
. The circuits
5
which are connected to the strain gauge are located at some distance from the strain gauge and include analog-to-digital converters, digital formatting and power regulation. The low-level analog signals from the strain gauge are connected to the circuits via a cable
6
. Though the combination works well, the cable must be assembled and connected by hand, thus increasing the manufacturing cost of the whole assembly.
It would be desirable to eliminate the cost of the manufacturing and assembly steps involving the inter connecting cable.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide a lower cost alternative to existing in-keyboard isometric pointing devices, such as earlier versions of the TrackPoint pointing device.
It is another object of the invention to provide a single pointing device which can use one of two alternative sizes of strain gauge for differing applications.
It is another object of the invention to provide a pointing device in which all the low-level analog signals are carried on very short printed wiring and are located in close proximity to the other circuits forming part of the pointing device.
These objects, and others that will become apparent to those skilled in the art, are provided by a computer pointing device including a printed wiring board having two sets of electrical pads defining a receiving space for connection and mechanical support of a large-size and, alternatively, a small-size strain gauge bridge network. The pointing device also includes a manipulation lever connected to the strain gauge for user input. The strain gauge is connected via the printed wiring board to a comparator and bias network. The comparator and bias network is connected via the printed wiring board to a micro-controller and power regulation circuit.
In a specific embodiment, the computer pointing device receives operating power input and a user manipulation input and provides a standard mouse-type output signal as defined by the IBM P/S-2 standard.
In another specific embodiment, the computer pointing device permits components of the bias network to be selected for balancing the strain gauge bridge network.
Another class of embodiments of the invention define an electrical interconnection component for a computer pointing device.
Finally, another class of embodiments of the invention define a computer pointing device sub-assembly, complete with all components except the strain gauge and the selectable bias components.
It is an advantage of the present invention to reduce the manufacturing cost of the TrackPoint computer pointing device by placing all the components on a single, small printed wiring board, thereby eliminating the cost of interconnecting a strain gauge sensor with remote electronics assemblies.
It is another advantage of the present invention to maintain control over potential electrical noise affecting low-lever analog signals by maintaining strict control over the low-level printed wiring line lengths.
Finally, it is an advantage of the invention to provide a single sub-assembly, including a strain gauge receiving space and all the necessary support electronics, which will accept one of a large-size strain gauge and a small size strain gauge.
REFERENCES:
patent: 4845319 (1989-07-01), Watkins et al.
patent: 5113955 (1992-05-01), Wallisch et al.
patent: 5489900 (1996-02-01), Cali et al.
patent: 5565865 (1996-10-01), So
patent: 5579002 (1996-11-01), Iggulden et al.
patent: 5588760 (1996-12-01), So
patent: 5607158 (1997-03-01), Chan
patent: 5615083 (1997-03-01), Burnett
patent: 5659334 (1997-08-01), Yangier et al.
patent: 5668358 (1997-09-01), Wolf et al.
patent: 5754167 (1998-05-01), Narusawa et al.
patent: 5767840 (1998-06-01), Selker
patent: 5793355 (1998-08-01), Youens
patent: 5876808 (1999-02-01), Selker et al.
patent: 6040823 (2000-03-01), Seffernick et al.
May Kim Wesley
Selker Edwin Joseph
Smith Barton Allen
Buckley Robert
International Business Machines - Corporation
Kumar Srilakshmi
Saras Steven J.
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