JPH0441385Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a signal detection pen for a capacitive coupling type coordinate input device.

[Prior Art] In a coordinate input device, a signal detection pen is brought into contact with a coordinate input panel to input desired coordinates. Electrode wires are arranged at predetermined intervals in two orthogonal directions on the coordinate input panel, and scanning pulses are sequentially applied to the electrode wires to generate electrostatic induction pulses at the detection electrode of the signal detection pen. Based on the size of , the contact position of the signal detection pen at that time is calculated. (For the calculation procedure, see, for example, Japanese Patent Publication No. 53-19380, Japanese Patent Application No. 59-37679.
See No. ) [Problems to be solved by the invention] Incidentally, in recent years, the development of systems related to graphic processing has progressed, and with regard to coordinate input devices, the number of coordinates detected when the signal detection pen is moved (hereinafter referred to as "number of coordinates detected when moving a signal detection pen") has been increased in order to support handwriting input, signature input, etc. This ability is called ``dynamic detection ability'').

Regarding this, when the applicant evaluated one of its products, it was found that if the number of detections per second when the signal detection pen is stationary on the coordinate input panel is 100, the peripheral speed is 1.75 m. It was found that when the signal detection pen was moved in a circular motion, the index was extremely deteriorated to 2 to 3.

The results of a study on this cause will be explained with reference to FIGS. 3 to 5. That is, in Figure 3, 1
is a coordinate input board, and X-direction electrodes 3-1 to 3-5 are placed on the upper and lower surfaces of the base film 2 at predetermined intervals.
..., ... and Y-direction electrodes 4-1, ..., ... are arranged, and protective coatings 5 and 6 are applied to their surfaces.

For example, to detect the X-direction coordinate, scan pulses are sequentially applied to each of the X-direction electrode lines 3-1 to 3-5, . This is done based on the magnitude of the electrostatic induction pulse.

According to the inventors' study, when the signal detection pen 7 is stationary, each of the X electrode lines 3-1 to
3-5, electrostatic induction pulses P-1 to P-5 as shown in FIG. In the pulse S-1 as shown in FIG.
~S-5 had occurred.

These pulses S-1 to S-5 are the pulse P-1
~P-5 has a noise of several hundred to several kilohertz superimposed on it, and this noise accumulates when performing a data check, that is, when performing coordinate detection for the same point more than once and comparing the data. Data mismatch →
This was considered an error, and the number of coordinate data sent from the device was decreasing.

When we further considered the cause of this noise, we found that when the signal detection pen 7 is moved, the detection tip 8 slightly moves up and down due to the subtle unevenness of the coating 5, and the electrode wires 3, 4 and this tip 8 It was found that this is the main cause of noise generation due to the instantaneous fluctuations in the capacitance between the two and the high impedance of the circuit.

[Means for solving the problem] Therefore, in the present invention, the sliding (up and down movement) of the detection electrode is
The electrostatic induction pulse generated in the detection electrode is supplied to the amplifier circuit (coordinate calculation means) via a capacitive coupling mechanism whose capacitance increases or decreases in response to.

[Function] In this way, X, Y due to the sliding of the detection electrode
The change in capacitance between each electrode wire is canceled out by the inverse change in capacitance of the capacitive coupling mechanism, and the above-mentioned noise is no longer generated.

[Example] Hereinafter, details of the present invention will be explained based on Example 11 shown in FIGS. 1 and 2. In the figure, 12 is a barrel which has a cylindrical shape. Reference numeral 13 denotes a tail plug, which has a substantially truncated conical shape and is fitted into one of the openings of the barrel 12. Reference numeral 14 denotes a circular hole bored in the center of the tail plug 13, through which a cable 15 connecting the signal detection pen 11 to the coordinate input device main body is inserted.

Reference numeral 16 denotes a base, which also has a truncated conical shape and is fitted into the other opening of the barrel 12. Reference numeral 17 denotes a circuit board on which necessary circuit parts 18 such as a preamplifier are mounted, and the tail plug 13 is attached to prevent movement inside the circuit board.
and is caught in the cap 16. 21 is base 1
6 is a circular insertion hole bored in the center thereof, and an insulating sleeve 22 is fitted and fixed inside the hole.

A detection electrode 23 is slidably housed in the insertion hole 21, and is connected to the flange portion 24 and the substrate end surface 25.
The signal detection pen 11 is biased toward the tip by a spring 26 compressed and inserted between the two.

Reference numeral 27 denotes a circular hole with a bottom, which is bored from the rear end side of the detection electrode 23 to near the center of the electrode 23 . 2
Reference numeral 8 denotes a sleeve, which is fitted and fixed into the bottomed hole 27.

Reference numeral 29 denotes a fixed electrode made of a round bar, which is slidably inserted into the insulating sleeve 28, and its rear end is fixed to the substrate 17 and connected to a preamplifier in the circuit component 18 via a conductive pattern 30. The output signal is supplied to the coordinate calculating means of the main body via the cable 15.

[Effect] If configured as in the present invention, the coating 5
As the signal detection pen 7 moves above the detection electrode 8, the coupling capacitance between the electrode 8 and each of the X and Y electrodes 3 and 4 increases or decreases instantaneously as the detection electrode 8 moves up and down (slides). Even if this happens, the coupling capacitance between the detection electrode 8 and the fixed electrode 29 will decrease accordingly, and as a result, the noise voltage as shown in FIG. 6 will not occur, and the dynamic detection ability will improve.

[Brief explanation of drawings]

Figures 1 and 2 show embodiments of the present invention;
The figure is a cross-sectional view taken perpendicular to the circuit board.
Figure 2 is a sectional view taken along a plane parallel to the circuit board, Figure 3 is a sectional view showing the signal detection pen in contact with the coordinate input board surface, and Figures 4 and 5 are the signal detection pen. FIG. 3 is a waveform diagram showing an example of electrostatic induction pulses that occur when the device is stationary and when the device is moving. 11...Signal detection pen, 23...Detection electrode, 2
7-29... Electrostatic coupling mechanism.

Claims (1)

[Scope of utility model registration request] It has a detecting electrode that is slidably held and a capacitive coupling mechanism whose capacitance changes in response to the sliding of the detecting electrode, and the electrostatic induction pulse generated in the detecting electrode is caused by the coupling mechanism. A signal detection pen characterized in that the signal is supplied to the coordinate calculation means via the signal detection pen.