Telegraphy – Systems – Position coordinate determination for writing
Reexamination Certificate
1997-06-20
2001-03-20
Shankar, Vijay (Department: 2673)
Telegraphy
Systems
Position coordinate determination for writing
C178S019030, C178S019040, C178S019050
Reexamination Certificate
active
06204457
ABSTRACT:
BACKGROUND OF THE INVENTION
Various electronic “digitizer pens” are used in conjunction with electronic digitizers, digitizer tablets, or the like. Such digitizer pens include replaceable ink cartridges used both for writing and mechanical activation of an internal “pen switch” when the tip of the replaceable ink cartridge is pressed against a digitizing surface of the digitizer pad or tablet to control the electronic operation of the digitizer pen in the digitizing process. (Although inking capability is not needed for digitizing of information that already is imprinted on a sheet of paper, use of an ink cartridge in a digitizer pen allows information to be digitized as it is being written on a sheet of paper placed on the digitizing surface.) Many of the prior digitizer pens are cordless and therefore battery powered. This necessitates efficient use of power to prolong battery life. In order to obtain an optimum transfer of the “pen signal” from a “pen coil” into the receiving grid conductors of a digitizer tablet, the highest possible signal strength must be achieved with the minimum dissipation of power. This necessitates use of an annular, cylindrical ferrite core around which the pen coil is wound and through which the writing tip of the ink cartridge extends.
A problem with prior electronic pens is that it is difficult to replace spent ink cartridges because a fixed ferrite core of the pen coil is positioned coaxially about the writing tip end of the ink cartridge so that only a very small portion of the writing end of the cartridge is ever exposed beyond the end of the ferrite core. This makes it very difficult for the user to grasp a spent ink cartridge sufficiently securely to remove it so it can be replaced with a new one.
While “standard” and non-standard ink cartridges have been used in various prior digitizer pens, for example as disclosed in U.S. Pat. Nos. 4,532,376, 4,638,119 and 4,227,044, which utilize pen coils, none of these references disclose a more modern digitizer pen structure in which the writing end of an ink cartridge extends through a fixed ferrite core around which a pen coil is wound, and none of these prior digitizer pens present the above-described difficulty of removing a spent ink cartridge from the pen barrel. One prior approach to solving this problem has been to provide special ink cartridges for use in digitizer pens, wherein the tip can be somewhat more easily grasped is the case for standard ink cartridges. Another approach, for example in a digitizer pen made by WACOM of Japan, is to provide an ink cartridge removal tool which is especially adapted to remove non-standard ink cartridges of its own design.
However, it would be much less expensive and more convenient to provide a digitizer pen in which standard, inexpensive, widely available ink cartridges can be used and in which they can be easily removed and replaced without using a specialized tool, or even any tool at all.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the invention to provide an improved digitizing pen structure and method in which an inking cartridge that extends through a ferrite core of a pen coil can be easily removed and replaced.
It is another object of the invention to provide an improved digitizer pen structure and method that avoids the need to use a tool to remove a spent inking cartridge that extends through a ferrite core of a pen coil.
It is another object of the invention to provide an improved digitizer pen structure that transmits a strong pen signal to grid conductors of a digitizer table, yet dissipates minimum power, and also is easily manufacturable.
It is another object of the invention to provide an improved cordless digitizer pen structure that transmits a strong pen signal to grid conductors of a digitizer table, yet dissipates minimum power and has long battery life.
Briefly described, and in accordance with one embodiment thereof, the invention provides a digitizer pen including a barrel section, a nose section adjacent to the barrel section, and an ink cartridge disposed in the barrel section and having a writing tip protruding from an end of the nose section, with a ferrite core disposed in the nose section, at least a portion of the ferrite core being permanently disposed in the nose section, a coil including a plurality of turns around the ferrite core, the ink cartridge extending through a hole in the ferrite core, at least the portion of the ferrite core being separable from the ink cartridge to expose a corresponding length of a writing end portion of the ink cartridge whereby a user can easily grasp the exposed portion of the ink cartridge and remove it without the aid of a tool.
In the described embodiments a cylindrical ferrite core is disposed in the nose section, a first portion of the cylindrical ferrite core being rigidly attached to the nose section. The coil is attached in fixed relation to the barrel section and includes a plurality of turns around a second portion of the cylindrical ferrite core. The ink cartridge extends through the first and second portions of the cylindrical ferrite core. The first portion of the cylindrical ferrite core is separable from the coil, so that when the nose section is removed from the barrel section the first portion of the cylindrical ferrite core is separated from the coil, leaving the coil attached in fixed relation to the barrel section and also leaving exposed a portion of the ink cartridge initially covered by the first portion of the cylindrical ferrite core.
In one embodiment the second portion of the cylindrical ferrite core is integral with the first portion thereof and also is separable from the coil. In another embodiment the first portion of the cylindrical ferrite core is separable from the second portion thereof, and the second portion of the cylindrical ferrite core is attached to the barrel section and remains in fixed relation to the coil when the nose section is removed from the barrel section.
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patent: 5866856 (1999-02-01), Holtzman
Caldwell Stephen R.
Shekhel Alexander B.
Cahill Sutton & Thomas P.L.C.
Fine Point Innovations, Inc.
Shankar Vijay
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