Abstract: A digitizer tablet is provided in which the working surface is illuminated by a light source which includes optical structure located over the grid or electrode array of the position determining structure of the digitizer to provide a surface-lit tablet, or beneath the grid or electrode array to provide a back-lit tablet. Preferably, a space is provided adjacent the working surface to reduce undesirable lighting effects. A fiber optics panel or an electroluminescent panel may be used as the optical structure placed above or beneath the grid to illuminate the working surface. The position determining structure and the optical structure may be integrated into a single unit to form a digitizer with an illuminated working surface, or the optical structure may be provided as a separate unit for use with a digitizer to provide an illuminated working surface for the digitizer.

Abstract: A digitizer tablet capable of reduced coordinate wobble due to beat interference between an induced display scan rate and the tablet scan rate by introducing a controlled delay to change the time between successive samples to increase the beat frequency to the point where it can be effectively filtered out.

Abstract: A digitizer tablet and puck(cursor) for use therewith, characterized that in one aspect the puck is provided with at least one additional control which will provide the user with the ability to control at least one N-dimensional signal in addition to the normal X-Y coordinate data. In accordance with another aspect, any pointing device for the tablet is provided with the capability to control the manner in which the N-dimensional signal varies in response to user manipulation of the pointing device.

Abstract: Stylus for digitizer tablet, with the stylus provided with a finger-actuated side control for controlling the magnitude of a Z-axis signal. The side control remains in the position placed by the user, and preferably comprises a slide switch mounted on the side of the stylus housing.

Abstract: A method for storing a k-bit output value for each of a plurality of m-bit input values in a memory having an n-bit word stored at each of 2.sup.n n-bit addresses, wherein m, n and k are positive integers, m>n>k and m-n.gtoreq.k, the method comprising the steps of storing a first k-bit output value corresponding to a first m-bit input value at a first n-bit address in the memory, and storing the 2n-m most significant bits of the first n-bit address at a second n-bit address, the stored 2n-m most significant bits of the first n-bit address occupying the 2n-m most significant bits at the second n-bit address, the first and second n-bit addresses being selected such that the n most significant bits of the first m-bit input value correspond to the n bits making up the second n-bit address and the m-n least significant bits of the first m-bit input value correspond to the m-n least significant bits making up the first n-bit address.

Abstract: A digitizer tablet consuming less power than is required of current tablets comprises short duration fast rise time energizing pulses, and a resonant circuit in the induced signal detector tuned to the frequency of the pulse repetition rate or preferably a higher frequency. Peak detector or timed sample and hold circuits are connected to the resonant circuit to improve resolution and reduce noise.

Abstract: A method and apparatus for indicating the position of a cursor on a surface in first and second different directions. The cursor is mounted on a member such as a gantry, and the gantry is guided for movement in the first direction on a carriage. The carriage is mounted for movement in the second direction on a member such as a rail. Radiation reflection strips extending and an acute angle with respect to one another are mounted on the gantry, and adapted to reflect light from a linear light source on said rail and extending in the second direction. Reflected light is sensed by a linear detector on said rail, for producing signals corresponding to the locations from which light was reflected. The coordinates of the cursor are determined by triangulation from these signals.

Abstract: A digitizer stylus with Z-axis side pressure control, comprising a nib front end resiliently mounted on the stylus housing and cooperating with a Hall-effect transducer such that side pressure on the nib, used like a calligraphic pen or brush, modifies the Hall-effect output, which can be used to modify an additional parameter, such as line width, of a drawing.

Abstract: A novel cursor construction for a digitizer tablet, wherein the cursor coil is wound on a one-sided bobbin which is then seated in a blind hole of a transparent base, with a crosshair molded into the base and aligned with the coil.

Abstract: Disclosed herein are position determining apparatus and conductor structures or grids therefor. The conductor structure for each axis includes a number of conductors, at least one of which is run in a serpentine path with a non-uniform repeat increment. The repeat increment, which is the spacing between one run and the next of the same serpentine conductor, is constrained by a maximum repeat increment, or a minimum repeat increment, or a maximum change in repeat increments between consecutive runs of a same conductor, or combinations thereof. In the preferred embodiments, there is at least a constraint on the maximum repeat increment to provide noise immunity. The conductors are arranged for each axis of the grid in a pattern such that signals obtained for that axis may be processed to provide binary members in a Gray-type code each unique to a small region of the active area in which the coil center is located.

Abstract: Digitizer tablet and digitizer tablet structure having an illuminable working surface are disclosed. A space between a top translucent layer having the working surface and a source of light is provided so as to eliminate or minimize undesirable lighting effects at the working surface. In the preferred embodiments, the space is an air gap (e.g. 0.060-0.250 inch) immediately adjacent the top translucent layer. The air gap is formed by transparent optical fibers or solid glass or acrylic rods. Back-lighted, translucent, back-lightable (without light source) and surface lighted digitizer tablet embodiments are described.

Abstract: An assembly utilizable with a digitizer cursor for increasing the accuracy of position determinations, wherein the cursor has cross-hairs for enabling the positioning of the cursor at a desired point on a digitizing surface, comprises in combination a magnifying lens and a connector for mounting the magnifying lens to the cursor in a region near the cross-hairs of the cursor. The connector includes a cradle or holder attachable to the cursor and a mounting arm connected to the lens, the cradle and the mounting arm being releasably connectable to one another. The mounting cradle is attachable exemplarily by adhesive to an outer housing surface of the cursor in a region near the cross-hairs. The mounting arm is integral with the lens, the lens having a polished surface and the mounting arm having relatively rough, unpolished, surfaces. Coacting locking elements are provided on the cradle and the mounting arm for releasably locking the lens in a predetermined position with respect to the cursor.

Abstract: A stylus having a pressure sensitive side switch for use with digitizer apparatus is disclosed. The pressure sensitive side switch is activated by the application of pressure thereto substantially normal to the axis of the stylus by the finger of a user. In the illustrated embodiments, the pressure sensitive switch comprises a movable element, and the switch provides a signal related to movement of the movable element substantially normal to the stylus axis. The switch output in the preferred embodiment is linearly related to movement of the movable element. The switch may comprise a magnet and a Hall-effect device mounted in the stylus for movement relative to each other. The pressure sensitive side switch may be used to control line width, coloring, gray scaling, Z-axis input, etc.

Abstract: A digitizer tablet using a pressure-sensitive pointing device preferably containing a linear transducer is provided with the means to convert linear pressure signals to logarithmically-related output counts. The conversion means is programmable to allow outputting of a logarithmically or a linearly related count for use by an application program.

Abstract: An optical device comprising a sheet of optical fibers having different lengths so that the fiber ends are distributed uniformly over a given area. The device is mounted in a digitizer tablet above or below its electrode array. When light is pumped into the free fiber ends, a pattern of light spots are formed which can be spread out to illuminate the tablet's working surface. When driven by a light pen, a similar optical device can be used to locate the light pen for menu-picking functions.

Abstract: A coordinate determining system, tablet, and method wherein the tablet is formed of a sequence of triangular electrodes extending in a first direction, with alternate electrodes having their apexes extending in opposite directions perpendicular to the first direction, and the bases of alternate electrodes are aligned to define the sides of the tablet. The cursor is round, having a diameter substantially equal to the length of the bases of the electrodes, and is adapted to be electrostatically coupled to the electrodes. Signals are sequentially applied to the electrodes and voltages generated at the cursor are employed to address look up tables for determining the location of the cursor.

Abstract: An electromagnetic digitizer system employing an interleaved array of individual conductors each in a W configuration bent into plural sections to define plural parallel portions distributed in different segments of a tablet such that each section comprises a center conductor portion connected in series with outer parallel portions such that the current in the center conductor portion splits or divides among the outer conductors and also flows in the opposite direction. Each of the plural sections defines two tablet coarse positions for a pointing device. Interpolation is employed to determine a fine position.