3-dimensional digitizer pen

Abstract

An electronic pen for a digitizer capable of providing signals to a computer for pen movement in three dimensions relative to a planar tablet. There is a hollow, pen-shaped body member having a writing tip end. A sensing coil is disposed in the body member adjacent the writing tip end and having wires thereof connectable to the computer for use in developing X- and Y-axis positional signals relative to movement of the writing tip end over the surface of the tablet. A pen member is disposed in the body member for longitudinal slidable movement within the body member. The pen member has a writing tip passing out through the body member at the writing tip end and an opposite inner end. Finally, there is a linear position transducer disposed within the body member for producing on output wires therefrom connected to the computer Z-axis positional signals relative to the pressing of the writing tip end against the surface of the tablet. In the preferred embodiment, the linear position transducer comprises, a source of a light beam; an opto-sensor for developing a signal at an output thereof proportional to light impinging on an input surface thereof; and, a reflector operably connected to the inner end of the pen member for reflecting the light beam onto the input surface proportionally to the linear position of the pen member within the body member. Provision is also made for outputting the Z-axis signal as a series of equal steps throughout an initialized range of motion/pressure.