JPH0571934U - Position indicator for digitizer - Google Patents

Abstract

(57) [Summary] [Purpose] To enable the cordless digitizer to accurately detect the position information of the position indicator and the switch pressing information. [Structure] Second that forms a constant loop on the position indicator 6 side
Coil (coil 6a4) or switches SW1 to S
An induction voltage is generated in the receiving coil group on the tablet side by electromagnetic coupling between the first coil (coils 6a1 to 6a3) formed in a loop by pressing W3 and the transmitting coil group on the tablet side. This induced voltage has a level difference due to the thickness of the acrylic member 6b which is an insulating member, and as a result, the position information of the position indicator 6 and the pressing information of each switch can be easily identified.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an electromagnetically coupled digitizer having a non-resonant cursor, and more particularly to a positioner for a digitizer wirelessly coupled to a tablet.

[0002]

[Prior Art]

 Conventionally, this type of digitizer has a transmitter coil group arranged in the X direction on the tablet side, a receiver coil group arranged orthogonal to the transmitter coil group, and a drive circuit for driving the transmitter coil group. It has a sense circuit for detecting the voltage induced in the receiving coil and a processing circuit for processing the detection output of the sense circuit. Then, the processing circuit controls the drive circuit to sequentially supply the current to the transmitting coil group. When the position indicator is mounted on the tablet, the current-transmitted transmitting coil and the position indicator are supplied. And are electromagnetically coupled, and as a result, an induced voltage is generated on the side of the receiving coil group. The generated induced voltage is detected by sequential scanning of the sense circuit. As a result, in the processing circuit, the X-direction position of the transmitting coil to which the current is supplied and the Y-direction position of the receiving coil on which the voltage is induced are detected on the tablet. Recognize the planar position of the position indicator.

FIG. 4 is a configuration diagram of the above-mentioned position indicator, which is composed of a coil portion 6A including a coil 6a and a main body portion 6B including a switch group SW and a resistor group R. ing. As shown in FIG. 4B, the coil portion 6A is covered on both sides with an acrylic member which is an insulating member. This position indicator has different resistance values connected in series with each switch, and when the switch is closed, the voltage level induced in the receiving coil on the tablet side by the difference in these resistances. Therefore, the processing circuit recognizes the switch depression information of the position indicator.

That is, when such a position indicator is placed on the tablet and none of the switches of the switch group SW is closed, the position detection as described above is performed and the position of the position indicator is detected. When any of the switches in the switch group SW is closed at the same time as the signal is detected, an induced voltage of a level corresponding to this is generated in the receiving coil on the tablet side, and this result processing circuit determines which switch of the position indicator. Recognize whether was operated.

[0005]

[Problems to be solved by the device]

 In order to accurately set the level of the induced voltage detected in the receiving coil, it is necessary to properly select the value of each resistance in the position indicator. That is, the error of these resistance values has a great influence on the induced voltage level of the receiving coil, and the induced voltage level fluctuates greatly even by a small difference such as a lot difference in resistance value. Therefore, it is necessary to strictly select the value of each resistance, which causes a problem of increasing the number of selection steps.

[0006]

[Means for Solving the Problems]

 In order to solve such a problem, the present invention is provided with a plurality of switches to generate an induced voltage in the receiving coil group on the tablet side by electromagnetic coupling with the transmitting coil group on the tablet side, and to display position information and switch operation information on the tablet. In the position indicator for the digitizer, which is transmitted to, the plurality of first coils that are connected corresponding to the plurality of switches and form a loop when the switches are turned on, and the second coil that constantly forms a loop and transmits the position information. A coil and an insulating member having a predetermined thickness and inserted between the plurality of first coils and between the first coil and the second coil are provided.

[0007]

[Action]

 An inductive voltage is generated in the receiving coil group due to the electromagnetic coupling between the transmitting coil group and the first coil that forms a loop when the second coil or the switch that constantly forms a loop is turned on. This induced voltage causes a level difference depending on the thickness of the insulating member, and as a result, position information and operation information of each switch can be easily identified.

[0008]

【Example】

 Next, the present invention will be described with reference to the drawings. FIG. 3 is a block diagram showing an embodiment of the position indicator for digitizer according to the present invention. In the figure, 1 is a transmitting coil group, 2 is a receiving coil group, 3 is a drive circuit, 4 is a sense circuit, 5 is a processing circuit such as a CPU, and these are all provided on the tablet side. By activating the circuit, the position of the position indicator 6 placed on the tablet and the operation information of the switch are detected.

That is, the drive circuit 3 is always controlled by the processing circuit 5, and an alternating current is sequentially supplied to each of the transmission coils of the transmission coil group 1 connected to the drive circuit 3 to generate a magnetic field. Now, when the position indicator 6 is placed on the transmitting coil group 1 to which electric current is supplied, the transmitting coil and the position indicator 6 are electromagnetically coupled, and as a result, a voltage is induced on the receiving coil group 2 side. It On the other hand, the sense circuit 4 is controlled by the processing circuit 5 to scan the receiving coil group 2 in the order of m-n, ..., M-1, m, m + 1 ,. Detected voltage. When the maximum induced voltage is detected in the sense circuit 4, the processing circuit 5 determines the position of the position indicator 6 from the position of the receiving coil selected at this time and the position of the transmitting coil that has supplied the current. I try to calculate it. The position indicator 6 is provided with a plurality of switches so that the position information of the position indicator 6 and the depression information of these switches can be detected.

Next, FIG. 1 is a diagram showing a specific configuration of the position indicator 6, and is a detailed cross-sectional view of a coil portion in particular. The position indicator 6 includes a coil portion and a switch portion SW. The coil portion is formed by stacking a plurality of coils 6a1 to 6a4 and inserting an acrylic member 6b, which is an insulating material, between these coils. As shown in FIG. 1 (b), the coil 6a4 laminated on the uppermost portion always forms a closed loop and is used for detecting the position of the position indicator 6, and the other coils 6a1-6a3 are respectively provided with the coil 6a4. Switches SW1 to SW3 are attached, and when these switches are pressed, the corresponding coil loop is closed, and as a result, the voltage corresponding to each closed loop of the coil is induced to the tablet side and the switch pressing information is recognized. It is supposed to be done. That is, the selected transmitting coil on the tablet side and the closed loop of the coil in the position indicator 6 are electromagnetically coupled, and as a result, a voltage is induced on the receiving coil group 2 side. The induced voltage decreases in the order of stacking the coils 6a1 to 6a4 in the position indicator 6. That is, when the loop of the coil 6a1 closest to the tablet side is closed, the induced conductive pressure becomes the largest, and the induced voltage in the case of the coil 6a4 which is always closed at the position farthest from the tablet side. Is the smallest. In this way, the position of the position indicator 6 and the switch pressing information are identified from the magnitude of the voltage induced on the tablet side.

FIG. 2A shows the state of lamination of the coils of such a position indicator 6, and FIG. 2B shows the waveform of the induced voltage according to the closed loop of each laminated coil. .. Here, as shown in (a) of the figure, when the thickness L of the acrylic member 6b inserted between the coils is set to about several tens of μm to several hundreds of μm, the level of the voltage induced in the receiving coil on the tablet side becomes As shown in (b) of the same figure, it becomes smaller in proportion to the stacking order of each coil, that is, the height from the tablet surface A. The identification range of the voltage induced in the receiving coil in this manner is determined by the sense circuit 4. That is, as shown in FIG. 2B, in the case of the coil 6a1, the discrimination range, in the case of the coil 6a2, the discrimination range, in the case of the coil 6a3, the discrimination range, and in the case of the coil 6a4, The identification range is defined. When defining the identification range, the upper and lower limits are set for each of the identification ranges 1 through 3, but it is not necessary to set the upper limit for the identification range and the lower limit for the identification range.

As described above, the coils 6a1 to 6a4 in the position indicator 6 are stacked in order from the tablet surface A, and the acrylic member 6b is inserted between these coils to connect the switches SW1 to SW1 connected to the coils. The difference in the level of the induced voltage on the tablet side caused by the depression of SW3 is caused by the thickness of the acrylic member 6a to identify the depression information of each switch. As a result, the level difference of the voltage induced on the tablet side can be obtained more stably than that of the method based on the connection of different resistance values as in the conventional example. Can be detected.

[0013]

[Effect of the device]

 As described above, according to the present invention, the induced voltage is applied to the receiving coil group by electromagnetic coupling between the transmitting coil group and the second coil which constantly forms a loop or the first coil which is formed by turning on the switch. Occurs. The induced voltage causes a level difference depending on the thickness of the insulating member, and as a result, the position information and the operation information of each switch can be easily identified.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a position indicator for a digitizer according to the present invention.

FIG. 2 is a diagram showing the relationship between the arrangement of coils that form the position indicator and the waveform of the induced voltage on the tablet side corresponding to the arrangement.

FIG. 3 is a block diagram of a digitizer.

FIG. 4 is a configuration diagram of a conventional position indicator.

[Explanation of symbols]

 1 Transmitting coil group 2 Receiving coil group 3 Drive circuit 4 Sense circuit 5 Processing circuit 6 Position indicator 6a1-6a4 Coil SW1-SW3 switch 6b Acrylic member

Claims (1)

[Scope of utility model registration request] 1. A transmission coil group arranged in a first direction, a reception coil group arranged in a second direction orthogonal to the first direction, and the transmission coil group are sequentially selected to generate an alternating current. Is provided on the tablet side with a drive circuit for supplying the above, a sense circuit for sequentially scanning the receiving coil group to detect an induced voltage, and a processing circuit for controlling the drive circuit and processing a detection output of the sense circuit. A digitizer position indicator that includes a plurality of switches, generates an induced voltage in the reception coil group by electromagnetic coupling with the transmission coil group, and transmits position information and operation information of the switch to the tablet, A plurality of first coils that are connected to correspond to the switches and that form a loop when this switch is turned on, and a first coil that constantly forms a loop and transmits the position information. Position indicator for a digitizer, comprising: a coil and an insulating member having a predetermined thickness and inserted between the plurality of first coils and between the first coil and the second coil. ..