JPS607290B2 - digitizer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a digitizer configured to be positioned by a pen stylus.

2. Description of the Related Art Conventionally, digitizers for inputting figures and the like into a computer have used a large coil called a cursor or a pencil-shaped detection element called a pen stylus for positioning.

The use of two types of elements for the same purpose each has its advantages and disadvantages. Although the cursor has good positioning accuracy, it has some drawbacks in operability, such as the need to look directly above the cursor to perform positioning operations. On the other hand, a stylus is superior to a cursor in terms of operability, but has the drawback of poor precision. The poor accuracy is due to the fact that the coil 2, which is the detection element wound around the stylus 1, cannot be placed at the positioning point P as shown in Figure 1, so when the stylus 1 is tilted, an error occurs even though the position of the tip does not shift. This is due to the fact that it occurs. In view of these points, it is an object of the present invention to provide a digitizer configured to reduce errors caused by tilting the stylus.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings.

FIG. 2 is a diagram showing the basic configuration of the digitizer according to the present invention.
The figure particularly shows the diamond part in cross section. That is,
In Fig. 2, 1 is a stylus, 2 is a detection coil, and 3 is a stylus.
indicates a drawing board, and 4a and 4b indicate conductor loops, respectively. The drawing board 3 is a flat plate made of non-magnetic material and having a constant thickness. The conductor loops 4a and 4b are arranged on the back surface of the drawing board 3, and are folded back at the edge of the drawing board to form a loop shape. Currents in opposite directions are passed through the conductor loops 4a and 4b. At this time, as is well known, the equipotential lines created by 4a and 4b are 4a and 4b
It will be a circle with the chord between L and 4.
The spacing between a and 4b and the vertical distance to point P (corresponding to the thickness of the drawing board 3) are selected. Further, the distance R from the tip la of the stylus 1 to the coil 2 is selected to be equal to the radius of the circle. Therefore, when the tilt of the stylus is changed, the coil 2 always moves on the equipotential line, and if the magnetic potential on the equipotential line is Q, the magnetic field day is H=
- Since the magnetic flux is given by the scales ado, the magnetic flux is always parallel to the axis of the coil 2 and is constant regardless of the inclination of the stylus 1.
In such a configuration, the position error x corresponding to the tilt angle of the stylus when positioned is shown in FIG. 3 based on experimental results.

As shown in the figure, in the range of 8 from 0 to 300, the error x due to the slope was less than 0.2 squares. FIG. 4 illustrates a case in which this principle is extended to two dimensions.

5a and 5b are conductor loops similar to 4a and 4b arranged in parallel with the conductor loops 4a and 4b through an insulating plate 6, and 4a and 4b are for measurements regarding the first axis, and 5a and 5b are for measurements regarding the second axis. It generates magnetic flux for

In reality, the first axis and the second axis are orthogonal, so the conductor loops 4a, 4b and the conductor loops 5a, 5b are arranged so as to be orthogonal to each other, but for the sake of explanation, it is assumed that they are arranged in the same direction. It is assumed. The conductor loops 5a and 5b are the conductor loop 4a.
, 4b, the distance between the loops 4a and 4b is narrower than that between the loops 4a and 4b in consideration of the thickness of the insulating plate 6. In the embodiment, the conductor loop is excited and the magnetic flux is detected by the coil, but the coil may be excited and the conductor loop is used to detect the magnetic flux.

In addition, the number of detection coils is not limited to one, but as shown in Figure 5, two or more coils are provided and these are coupled differentially, and the configuration is configured to detect the divergence of magnetic flux at the position of the coil. You may. In this case, as shown in FIG. 6, the error x due to inclination can be reduced over a wider range of angles 8. Note that the coupling of these coils is not limited to just differential coupling; it is also possible to connect individual amplifiers and calculate their outputs to determine the position, and the number of turns of the coils does not necessarily have to be the same. There isn't. As described above, according to the present invention, it is possible to realize a digitizer that can reduce errors caused by the tilt of the stylus. In addition, in a two-axis digitizer, the interval between the conductor loops on the side closer to the surface of the drawing board is wider than that on the side far away, and each conductor loop is located on equivalently the same equipotential line, so that the first axis and Errors caused by the tilt of the stylus can be reduced with respect to both of the second axes. Furthermore,
By providing two or more detection coils, errors can be reduced, and the effect is significant in practical use.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a conventional digitizer, FIG. 2 is a diagram showing the basic configuration of the digitizer according to the present invention, FIGS. 3 and 6 are diagrams showing the magnitude of error caused by the tilt of the stylus, and FIG. FIG. 4 is a block diagram of the main parts of a two-dimensional digitizer, and FIG. 5 is a block diagram showing another embodiment of the present invention. 1...Stylus, 2...Coil, 3...
...Drawing board, 4a, 4b, 5a, 5b...Conductor loop, 6...Insulating board. Figure 3, Figure 4, Figure J, Figure 3

Claims (1)

[Scope of Claims] 1. A conductor loop is disposed on a drawing board, and when the tip of a stylus around which a coil is wound is positioned on the drawing board surface, the conductor loop and the coil are substantially centered on the tip of the stylus. A digitizer configured to be located on the same circumference. 2. The conductor loop is a two-axis conductor loop consisting of an X-axis conductor loop and a Y-axis conductor loop orthogonal thereto, and the interval between the conductor loops for one axis arranged on the side closer to the drawing board surface is 2. The digitizer according to claim 1, wherein the distance between the conductor loops for the other axis is wider than the distance between the conductor loops for the other axis disposed on the side far from the drawing board surface. 3. Claim 1, wherein the coil is a plurality of coils arranged in parallel in the axial direction of the stylus.
Digitizer as described in section. 4. The digitizer according to claim 1, 2, or 3, wherein the conductor loop is excited and magnetic flux is detected by the coil. 5. The digitizer according to claim 1 or 2, wherein the coil is excited and magnetic flux is detected by the conductor loop.