Computer graphics processing and selective visual display system – Display peripheral interface input device – Light pen for fluid matrix display panel
Reexamination Certificate
1993-10-08
2001-01-09
Wu, Xiao (Department: 2774)
Computer graphics processing and selective visual display system
Display peripheral interface input device
Light pen for fluid matrix display panel
C345S180000
Reexamination Certificate
active
06172668
ABSTRACT:
The present invention relates to a pen-like device having a light output, hereinafter referred to as a light pen.
BACKGROUND OF THE INVENTION
Light pens are commonly used as input devices for data processing and storage systems in place of conventional keyboards and mouse devices. A light pen is used in combination with a display screen incorporating a photosensitive digitizer or photosensitive sheet material. As such, information can be input by writing with the light pen on the screen and typically the screen displays the instantaneous position, and path of movement, of the pen. In this way, the screen displays the pattern, e.g. a written message, sketch or signature traced thereon.
The light source for known light pens disadvantageously comprises a relatively fragile lamp or L.E.D. which can readily suffer damage if the pen is dropped. The light source is powered either by way of a power supply cord or cable or by way of a battery if a “cordless” light pen is required. The power is supplied by way of electrical connections which may also be fragile and prone to breakage if the pen is dropped or otherwise misused. Such components are generally expensive to purchase and assemble.
Cordless light pens are advantageous in that the movement and use of the pen is not impaired by a cord which can easily become snagged or otherwise interfere with the light pen. Also, a single cordless light pen can be used with a plurality of digitizer units, or other devices, since the pen is not anchored to one unit by a power supply cord.
However, known cordless light pens suffer particular disadvantages in that a battery must be provided for its use, which increases the operating cost of such pens. If a replaceable battery is used, this further increases the cost and also makes operation of the pen dependent on the availability of a replacement battery. If a re-chargeable battery is employed this may also lead to an increase in the “down time” for the pen, i.e. the period during which the pen can not be used.
OBJECTS OF THE INVENTION
It is an object of the present invention to provide a new and improved light pen for use as a data input device.
It is another object of the present invention to provide a light pen which does not require a lamp for generating a light output.
It is a further object of the present invention to provide a “cordless” light pen which does not require a battery.
It is yet another object of the present invention to provide a light pen which is light weight, mobile and has improved durability.
It is yet a further object of the present invention to provide a light pen which is less costly to operate than those of the prior art.
It is still another object of the present invention to provide a light pen which eliminates the “down time” experienced by known light pens.
It is still a further object of the present invention to provide a light pen which does not require electrical connections and relatively fragile components.
It is another object of the present invention to provide a light pen having improved mechanical strength, and thus resistance to accidental damage.
SUMMARY OF THE INVENTION
According to the present invention there is provided a light pen having an elongated body member with a tip from which light is output. The body member includes photoluminescent material, whereby light radiated by the photoluminescent material in response to external light is directed by a process of internal reflection to the tip for output therefrom.
REFERENCES:
patent: 2553245 (1951-05-01), Espenchied
patent: 4800257 (1989-01-01), Johner
patent: 5083120 (1992-01-01), Nelson
patent: 5116533 (1992-05-01), Grandmont et al.
patent: 59053974 (1984-03-01), None
patent: 59-053974 (1984-07-01), None
patent: 2219086 (1990-08-01), None
NCR Corporation
Wu Xiao
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