Telegraphy – Systems – Position coordinate determination for writing
Reexamination Certificate
1999-05-06
2001-06-26
Saras, Steven (Department: 2675)
Telegraphy
Systems
Position coordinate determination for writing
C345S179000
Reexamination Certificate
active
06252182
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to computer input devices such as digitizers or tablets and more particularly to a method and apparatus for generating variable width lines using pressure sensitive techniques or simulation thereof.
BACKGROUND OF THE INVENTION
Currently, the widely used computer input devices include keyboard and mouse. Due to the advance of the digital technologies, more and more computer users start to work with digitizer based devices such as digitizers or tablets which allow a user to write and draw upon the surface of a touchpad and have the signals and codes interpreted by a computer. Specifically, the touchpad provides a writing surface for capturing the position and the orientation of an object. In cooperation with the touchpad, a pen-like device is required to create such objects. Most existing pen-like devices, which can be corded or cordless, are not able to generate lines with variable width. To overcome this shortage, pressure sensitive pens are invented. In general, the existing pressure sensitive pens are classified into three categories: 1) capacitive pen, 2) resistive pen, and 3) dual iron-core inductive pen.
No matter which kind of pressure sensitive pen is employed to produce lines with variable width, the basic idea of pressure sensitive techniques is to utilize the variation of the pressure detected. When a resistive pen is used, the pressure variation is difficult to be felt and to be controlled by a user since the working stroke is too short. Consequently, it is difficult to directly present variable thickness of lines using a resistive pen. Capacitive type of pens suffer from similar problems. Dual iron-core inductive pens seem able to overcome the problem and generate lines with variable width. However, the dual iron-core inductive pens have their own drawbacks such as high cost, low production rate.
Based on the findings of the aforementioned drawbacks, it is therefore desirable to introduce an improved method and apparatus to control the pressure variation easily so as to directly present different thickness of lines when a user writes or draws on the surface of a touchpad.
SUMMARY OF THE INVENTION
It is known that the resistance of an element varies proportionally with the resistivity of the material and the element length, is inversely proportional to the cross section area of the element. Utilizing these properties, in accordance with the present invention, a resistive pressure sensitive electromagnetic pen is invented to solve the problems of short strokes and pressure variation control, so as to directly present different thickness of lines when writing or drawing.
An object of the present invention is to provide a resistive pressure sensitive pen comprising a pen core and a clamp casing. Inside the clamp casing, there is an offset space where a conductible rubber and a coil circuit board are placed. Further, in correspondence with the conductible rubber, spiral circuit is printed on the surface of the coil circuit board. When the pen is used, pressure force is exerted on the pen core, which presses the conductible rubber against the coil circuit board. Different levels of pressure result in different contact lengths and contact areas, consequently, different values of resistance which can be used to present different width of lines.
Another object of the present invention is to provide a pressure sensitive pen comprising a pen core support. On one end of the pen core support, there is a polygonal notch. Utilizing the friction between the sides of the notch and the pen core, the pen core can be secured within the polygonal notch appropriately.
Yet a further object of the present invention is to provide a pressure sensitive pen having an elastic element. The elastic element can move the pen core support to its unactuated position to avoid contact between the conductible rubber and the coil circuit board when the pressure sensitive pen is not used. Hence, no errors would occur.
The foregoing has outlined rather broadly the objects and technical advantages of the present invention. These and other objects and advantages of the present invention will become more apparent from a consideration of the following detailed description of a preferred embodiment thereof, when read in conjunction with the accompanying drawings, wherein:
REFERENCES:
patent: 5565632 (1996-10-01), Ogawa
patent: 5581052 (1996-12-01), Padula et al.
Aiptek International Inc.
Kumar Srilakshmi
Saras Steven
LandOfFree
Digital pressure sensitive electromagnetic pen does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Digital pressure sensitive electromagnetic pen, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Digital pressure sensitive electromagnetic pen will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2469819