JPH012125A - Digitizer needle with pressure transducer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates generally to pressure-responsive needles of the type used in conjunction with digitizer tablets, and more particularly to pressure-responsive needles having a layer of pressure-responsive ink and primarily for use with digitizer tablets. It relates to a needle intended for use in signal verification systems or graphics digitizer tablets.

[Conventional technology]

In operation, an electrical connection is made between the needle and the digitizer tablet, and the position of the needle on the digitizer surface is determined by the connected signal. The needle and digitizer tablet combination is commonly referred to as a "digitizer."

The earliest digitizers were mechanical devices with limited arms. More advanced digitizers also have a freely moving needle, and to determine needle position,
To connect the needle and digitizer tablet,
Various devices are used. Connections can be electromagnetic, electrostatic,
It is based on acoustic, piezoelectric, magnetostrictive, optical, etc. principles.

The tablet surface includes a crossed grid of wires, an electrode matrix, and a resistive surface. - Generally, these devices rely on signals introduced within a plurality of X and Y referenced conductors or within a resistive film.

The needle is a hand-held device that presses against the digitizer tablet surface, similar in that it resembles that of a conventional ballpoint pen. The housing of the needle has an electrode that connects to the digitizer tablet surface, where a capacitive connection is used.
The various circuit elements, including electrical windings, are provided with dielectric connections suitable for the above-mentioned concept underlying the operation of the digitizer.

The data obtained from the needle/tablet combination is input to an electronic circuit that converts the signal into data representing the position of the needle seat on the tablet, or used in conjunction with a microprocessor to generate a display. Convert to driving signal. For the display.

Either numerical coordinates of the position of the needle or a graphical representation of the position of the needle in terms of indicated points, or both, may also be shown.

For orderly operation of the device and prevention of spurious data entry, it is desirable for the entire system to operate only when the stylus is intentionally pressed against the digitizer tablet surface. For this purpose, the needle may be remoted from the data processing circuitry, or the needle may be connected during operation as desired.
A switching element is typically included within the needle housing.

The switching element varies by configuration and includes a simple electromechanical switch that is energized by slight movement of the needle point into the needle housing as the needle point is pressed against the digitizer tablet surface. .

In other configurations, the point of the needle is pressed against the digitizer tablet surface and the core is moved within the induction coil as the point is retracted slightly within the needle housing.

This core movement changes the output from the induction coil,
Provide a signal to excite the needle.

Capacitive switching is also used, where a capacitive plate is connected to the needle and moves relative to the opposing capacitor plate as the needle is pressed against the digitizer tablet surface. This motion induces a signal that excites the system.

Switches that are actuated directly by the needle are available in the form of switch buttons and switch handles that are mounted on the outside of the needle housing.

[Problem to be solved by the invention]

A problem with prior art needles is that they are bulky, complex, and the switch described above that initiates active use of the needle is expensive.

Reliable on/off using small, economical components
A needle construction that includes an off switch or pressure function is required.

Another problem with prior art needles is that axial tip movement is required for energizing the switch.

[Means to solve the problem]

The present invention provides a type of needle switch that is automatically energized when the needle is pressed against a digitizer tablet.

The needle pressure switch of the present invention includes a transducer in the form of an ink layer having an electrical resistance that varies as a function of the pressure applied to the layer. the electrode contacts the ink layer transducer;
A circuit including a variable resistor is provided. Each electrode is formed as a layer of conductive ink.

When the switch is used with a needle, the small segments of this layered structure allow mechanical forces to be transferred through the surface in response to pressing the needle against a hard surface, such as those used in digitizer tablets. Installed to compress the transducer.

The resistance of the transducer layer changes depending on the applied pressure.

Therefore, the current flowing between the two dielectric ink electrodes changes as the pressure applied to the switch changes, providing an analog output that is also indicative of the pressure.

Processing circuitry connected to the electrodes detects a threshold level of change in pressure as an indication of a changed on/off state of the needle and optimally energizes the associated digitizer circuit.

In other words, the data stream from the needle is processed only if the pressure with which the needle tip contacts the digitizer tablet exceeds a predetermined value. This predetermined value means that the needle is
For example, the pressure is selected to be less than or equal to that generated when used for signing. Thus, the data flow is processed during signing.

Upon removal of the digitizer dot from the tablet surface, the needle returns to its standby state, where no pressure is applied on the ink layer.

Pressure transducers include one manufactured by Interlink Electronics, Sunta Barbara, Calif.
Ink Electronics) force sensitive resistor (
FSR) includes a layer formed of transducer ink. This type of material changes its resistance when compressed by force applied to its surface.

A dielectric electrode contacts the split portion of the surface of the FSR transducer ink layer such that a complete circuit is formed between the conductors through the FSR transducer ink layer.

The conductor is, for example, manufactured by E.I. DuPont (E,I.

It is formed by a layer of conductive ink manufactured by DuPont Corporation. The conductive ink electrodes and ink layer transducers are printed on a thin Mylar layer that is folded together. The electrodes are pressed against the transducer to complete the electrical circuit.

When the digitizer device is activated but the needle is still not in use, a voltage can be applied across the FSR transducer through the terminals of the needle and the conductive electrodes.

Thus, when the needle tip is pressed against the digitizer tablet and surface, the FSR transducer ink layer is compressed between the surfaces of the two opposing parts, one part being
is displaceable when pressure is applied on the tip of the needle;
The other part is at rest.

When the FSR transducer ink layer is compressed, its electrical resistance causes a change in current and/or voltage at the output terminal.

change as it occurs. This change is used as a trigger to enable processing of the obtained data by the digitizer-electrical circuit.

In a preferred embodiment, coordinate determination data is obtained from a needle that is capacitively connected to an actuated pole within the charge ratio tablet. However, it will be apparent to those skilled in the art that coordinate determination data may be obtained from the electrodes of the charge ratio tablet in response to actuation of the needle.

In one preferred embodiment of the invention, the portion displaceable relative to the FSR transducer when pressure is applied to the needle tip is resilient and substantially planar. The resistance change of the transducer ink layer in this example is a function of pressure.

In this way, a relevant analog signal of the force applied to the tip of the needle is obtained. This analog signal can be used when drawing one mechanical or electrical drawing, and the varying forces can be used, in addition to the uses already noted, e.g. in connection with signature verification, or during the digitization of circuits, etc. Indicates the use or necessity of lines of varying thickness.

In another embodiment of the invention, the portion displaceable relative to the transducer when pressure is applied to the tip of the needle is resilient and rounded, such that the portion attached to the transducer The area of increases with increasing pressure. The change in resistance in this embodiment is a function of the pressure and the change in surface area of contact between the displaceable part and the transducer.

A first object of the present invention is to turn on/off in response to displacement of the needle tip relative to the needle housing during writing.
The object of the present invention is to provide a superior digitizer needle that provides off-switching.

A second object of the present invention is to provide an improved needle switch that is reliable, compact, and inexpensive to manufacture.

A third object of the present invention is to provide an improved digitizer needle that provides an analog output indicative of the pressure exerted by the needle tip against the digitizer tablet surface.

A fourth object of the present invention is to provide tactile feedback to the user indicating when sufficient pressure has been applied to excite data flow from the needle.

Still other objects and advantages of the present invention will be partly apparent, and partly will be apparent from the specification.

〔Example〕

Preferred embodiments of the invention will now be described in detail with reference to the accompanying drawings.

The needle (1) is shown in partial cross-section in FIG.

A pen refill (2) is arranged in a hole in the inner barrel projection (4). The pen refill (2) can be a standard pen refill, as shown in FIG.

The plastic cap (3), shown in phantom in FIG. 2 together with the refill, is removed before assembly of the needle.

In this example, the pen refill is made of stainless steel and is manufactured by A.
Provided by T-Cross. The inner barrel projection (4) is a cylindrical sleeve with a hole with a sufficiently large radius to facilitate the insertion of the pen refill (2).

The tip of the pen refill (2) connects the refill to the nose.
It extends through a hole in the nose cap (6) with sufficient play to allow it to be displaced axially relative to the cap. The nose cap (6) is made of molded plastic.

Flexible plate (22) while electrostatic discharge metal refill body (2)
A rubber washer (8) is arranged between the nose cap (6) and one end of the inner barrel projection (4) to prevent this from occurring. As best shown in FIG. 3, the inner barrel protrusion (4) and the inner barrel (10
) is a friction fit. Various views of the inner barrel (10) are shown in Figures 78-7c and will be described in detail hereinafter.

The end of the refill body (2) extends beyond the end of the inner barrel projection (4) and inside the inner barrel (1o). The refill body (2) and its end are received by a refill interface plug (12) (see FIG. 3), which is arranged within the inner barrel (2o).

The refill interface plug (12) is connected to the hole (15
) (Figures 5B and 5C), 4 extending in the axial direction.
A friction fit is provided on the end of the refill body (2) by means of circumferentially arranged ribs (14). The base (16) of the refill interface plug (12) is provided with a planar radial surface (18).

Circular and cylindrical plunger (20) (see Figure 3)
are arranged inside the inner barrel (10), the planar radial end surface (21) abutting the planar radial surface (18) of the refill interface plug (12).

The inner barrel (10) and inner barrel projection (4) have a flexible plate (22) wrapped around them.

The flexible plate (22) includes electric circuit boards (24a) to (24g
) and applied to the plate is an FSR converter (26
) is a flexible substrate having a circular layer of quantity sensing resistor (FSR) ink. The flexible plate (22) is shown in its unenclosed state in FIG.

The electrical circuit includes an anode (24a), a conductive connection (24b)
), (24c) and (24h) are included. The connecting portion (24h), the terminal (24e), and the electrode (24f) are electrically connected.

The connection part (24c) is a terminal (24d) and an electrode (24b).
Connect electrically. The connection part (24b) is connected to the anode (24
a) is electrically connected to the connection part (24c). In a preferred embodiment, the electrical circuit and FSR transducer are formed by applying a layer of conductive ink.

The flexible substrate takes the form of a Mylar film. 9th
As best understood from the figure, this substrate includes a rectangular section (28a), a polygonal section (28c), a bridge or neck section (28b) connecting sections (28a) and (28c).
, and through the individual neck or bridge portions (2
8b) has an asymmetrical configuration including a curved portion (28d) having a configuration formed by a pair of circular portions connected in series.

As best seen in FIG. 8, portion (28a) is wrapped around the inner barrel projection (4) and portion (28a)
9c) is wrapped around the inner barrel (10).

finger tab (88) with which the flexible plate (22) is handled during encirclement;
The winding is finally removed by cutting along the hole (90) after the stage is completed.

As best seen in Figure 3, portion (28d) is folded twice during assembly of the needle. The FSR transducer (26) is folded 180° under and in contact with the electrodes (24f) and (24g), which in turn are relatively 9 inward
0″ folded.

As best understood from Figure 7B, the inner barrel (1
0) has a hole consisting of parts (34a)-(34d).

It has a cutout (30) communicating with the hole portion (34d), through which the folded FSR transducer (26) and electrodes (24f) and (24g) are connected during 90° folding. ,pass.

This moves its folded portion from a position substantially tangential to the outer periphery of the inner barrel (10) to an inner side of the inner barrel (10) and substantially along the inner barrel axis m.
c32) to a position tangential to it. In this latter position, the FSR transducer (26) is connected to the electrode (
24f) (24g) and the opposite radial planes (23) of the plunger (20).

As shown in FIG. 7B, the inner barrel (10) includes a series of communicating through-hole sections (3) disposed along the longitudinal axis.
4a) - (34d). Hole part (34a)
teeth.

It is a conical hole with circumferentially arranged axial ribs (36). The end of the hole portion (34a) has a chamfered portion (38
)have. The ribbed hole portion (34a) receives the end of the inner barrel projection (4), which is held in place within the hole portion (34a) by a friction fit.

The end face of the inner barrel projection (4) abuts an annular shoulder (42) on one side of the bore portion (34b). Hole part (34
b) is provided with another annular shoulder (30) against which the refill interface plug (12
) come into contact (see Figure 3).

The sleeve portion (17) of the refill interface plug (12) is seated within the bore portion (34c).

Base (1) of Refill Interface Plug (12)
6) The plunger (20) and the inner barrel plug (
36) along with the sleeve portion (54) of the hole portion (34d
) is seated within. Refill interface plug (
12) and plunger (20) are attached to the inner barrel (10)
can be slidably displaced in the axial direction relative to the

The inner barrel plug (36) is glued inside the inner barrel (10) so that it is axially fixed.

The shoulder of the flange (52) of the inner barrel plug (36) (see Figure 6B) is attached to the end face (44) of the inner barrel (10).
), and this end surface has an annular shape except for a discontinuous portion corresponding to the notch (30).

Plunger (20) in the preferred embodiment is in the form of a neoprene slutz. The plunger (20) is
While applying pressure on the needle tip, it is elastically compressed. When pressure is removed from the needle tip, the refill interface plug (12) and the refill body (2) are restored to their original positions by expansion of the elastic material of the plunger (20).

The inner barrel plug (46) has a flange (52);
A sleeve portion (54), an axial hole (50) passing through the flange (52), and a base (50) that closes one end of the hole (50).
48) (see Figure 6B). The outer circumference of the sleeve part (54) is slightly conical and has circumferentially distributed axial grooves (56) thereon (
(See Figure 6C).

The base (48) has a planar end surface (58) on which the inner barrel plug (46) is attached to the inner barrel (1).
substantially transverse to the axis (32) when the tip of the needle is pressed against the surface.

The FSR transducer (26) and electrodes (24f) (24g) are connected to opposite planar radial surfaces, namely the end face (23) of the plunger (20) and the end face (6) of the inner barrel plug (46).
8) is pressed between.

As can be seen, the pressure exerted on the FSR transducer (26) by these opposing surfaces is approximately equal to the pressure exerted by the user on the tip of the refill body (2). When the refill chip is pressed against the working surface of the data tablet, the end of the refill (2) presses against the inner surface of the base (16) of the refill interface plug (12). The basic end face (18) of the base (16) conversely transmits the compressive force to the radial end face (21) of the plunger (20), and the other radial end face (23) of the plunger (20) conversely Then, the compressive force is converted into FSR converter (26)
give to

Inner barrel plug (
The radial end face (58) of 36) provides a stable base against which the FSR transducer (26) and electrode (2
4) (24f) (24g) is the movable plunger (
20).

As best seen in FIG. 1, the cable assembly (60) includes two radially outwardly directed projections (60) formed on the periphery of the cable assembly (60) and the sleeve portion (44). 92) (92”) is connected to half-off (66) (68).

The protrusions (92) (92') are engaged with a pair of holes formed along the joints of the planted half-holes (66) and (68), and each half-hole is attached to a half of the guard hole. is forming. The hole, of course, has the same shape as the protrusion. Projection (92
) (92') and the aforementioned holes, the cable assembly (60) is fixed relative to its assembled halves (66) (68).

Each half hole has a circumferential rib (
86). When halves (66) and (68) are assembled, opposing ribs (96) (only one of which is visible in FIG. 1) are located axially to the left of inner barrel assembly (64). to prevent displacement.

Since the inner barrel assembly (64) cannot undergo left axial displacement (as shown in FIG. 1), the movable plunger (20) (see FIG. 3).

When displaced axially to the left in response to the tip of the needle being pressed against the surface, the FSR transducer (26) and electrodes (24f) (34g) move against the planar radial surface (23).
and (58).

After that, the inner barrel (10), the refilling interface
Plug (12), plunger (20), inner barrel
The assembly of plug (46) is generally referred to as the inner barrel assembly (64).

Terminals (24d) and (24e) are soldered to respective terminals (62) (62') of cable assembly (60). The cross-sectional view in Figure 4 shows the terminal (24e)
The connection of the terminal (62) to the terminal (62) and the connection of the terminal (12') to the terminal (24d) are shown.

In addition, a core spacer tube consisting of a cylindrical sleeve (70
) in the hole (50) of the inner barrel plug (36).
) is inserted within. The hole (50) is slightly conical and allows the core spacer tube (70) to be press fit therein. The core spacer tube (70) is connected to the connected terminal (
62) (24d) assembled terminal (62') (2
4e) Prevent contact with

A soldered subassembly consisting of a cable assembly (60) and an inner barrel assembly (64) is arranged inside the left and right halves (66) (68). Flexible plate terminal (24d) (2
4e) is half-day (66) (68) key rib (96)
) (see Figure 4).

As can be best understood from Figure 4, the left side half rest (68)
is a pair of axial protrusions (66) that engage with the right half-rest (66).
72) and (72'). The halves are ultrasonically glued along the protrusion/half interface, and this ultrasonic adhesion contributes to electrostatic discharge of the needle.

During assembly, O-rings (76) and (78) were partially closed (
66) and (68) are installed in circumferential grooves formed on the outer peripheral edges of the parts. O-rings (76) and (78) hold the halves together during ultrasonic bonding. The circumferential overlap of the half-holes (66) (68) in the area of the ultrasonically bonded joint further provides excellent protection against external electromagnetic interference.

After the halves (66) and (68) are secured together, a self-adhesive rubber washer (8) is installed in the cutout provided in the nose cone (6). Nose cone (6)
Then use glue to make that ultrasonically glued semi-vacuum (
66) and (68).

Next, the outer barrel (80) is located near the nose cone.
Until the ring (76), its ultrasonically bonded half-hole (66)
and (68) are slid on. An adhesive applied along the periphery designated by reference number (86) allows the outer barrel (80
) is attached.

Thereafter, end caps (84) are attached to the other ends of outer barrel (80) and cable assembly (60), respectively.
) is attached to the strain removal part.

Cable assembly (60) includes a coaxial cable. The coaxial cable shield is made of a flexible plate (
22) is connected to the terminal (24e) of the terminal (22). In other words.

The terminal (24e) is connected to ground. Terminal (24d)
is connected to provide an analog signal through a coaxial cable to a digitizer electrical circuit (not shown) for the purpose of determining the level of dC bias.

The level of dc bias between terminals (24d) and (24e) can be varied by connecting the variable resistor of the FSR converter therebetween.

The pressure-responsive needle according to the present invention has a charge ratio digitizer.
Used in conjunction with tablets. As disclosed in commonly assigned U.S. Patent Application Ser. can be sampled during separate sampling cycles. In this sampling cycle, the needle is disabled in such a way that a current is capacitively induced into the anode (24a) of the needle.

Instead, the terminal (24d), conductor (24c), electrode (24c)
4g), a voltage is applied across the terminals (24d) and (24e) to generate a current in the circuit formed by the FSR converter (26), the electrode (24f), the conductor (24h), and the terminal (24e). .

The FSR transducer (26) folded and in contact with the electrodes (24f) and (24g) acts as a variable resistance.

The FSR transducer (26) is made of a force responsive resistance (FSR) material whose resistance varies in response to the amount of compressive force applied in a direction substantially perpendicular to the plane of the transducer layer.

A graph of the resistance of the FSR transducer as a function of applied compressive force is shown in FIG. 10 for three sample needles. As best seen in Figure 10, the resistance of the FSR transducer (26) decreases as the magnitude of the compressive force increases. The resistance change of the FSR material is caused by the dc of the analog signal output at terminal (24d) in response to the reference signal input at terminal (24e) during a pressure sampling cycle by an electrical circuit introduced within the digitizer tablet. Generate a corresponding change in level.

The dc level of the analog signal can be detected using a comparator (not shown) included within the digitizer electrical circuit. What is the DC level of the analog signal?

It is compared with a reference voltage applied to a comparator. As the pressure on the needle tip increases, the resistance of the FSR converter (26) decreases, thus increasing the dc level of the analog signal.

When the analog signal dc level exceeds the reference voltage, the output of the comparator goes high. As the output of the comparator goes high, a switch is closed that allows the flow of digitized data from the needle to the processing circuitry of the digitizer electronics during the electrode drive cycle.

Digitized data may also be digitized in response to signals induced at the anode (24a) by the electrode or electrodes of the charge ratio tablet during the drive cycle, as disclosed in co-pending U.S. Patent Application No. 000. , from the flexible plate to the terminal (2
4d) and at different points in the sampling cycle.

The FSR converter (26) therefore functions as a variable resistance and a switch in the digitizer-electrical circuit is closed in response to the variable resistance achieving a predetermined value. This predetermined resistance value should be achieved at a pressure slightly below the amount of pressure that is applied overall on the tip of the pen refill when the needle is used for writing purposes by the user. - This feature allows an individual's handwriting to be digitized, especially for signature verification purposes.

The relative coordinates of the needle tip to the digitizer tablet are determined only for those positions of the needle tip, at which positions the pressure of the tip against the tablet exceeds a predetermined pressure value. That is, the position is determined only when the lead is being used for writing purposes.

This predetermined pressure value is the pressure at which the analog signal output from the needle exceeds a stored predetermined analog value. In response to a needle output signal exceeding a predetermined stored value, needle tip coordinates are initiated. Also, coordinate determination is aborted when the pressure applied by the needle tip falls below a predetermined stored value.

In the preferred embodiment described in connection with FIGS. 1-10, the FSR transducer is compressed between two substantially rigid planar semi-radial surfaces.

-203. In another preferred embodiment shown in FIG. 11, the movable plunger (20) is made of flexible material and
It has a rounded surface (21) (represented by dotted lines in FIG. 11) that compresses the transducer. In the case of such an elastic, rounded compression surface, the contact area of the surface (21) with the portion of the flexible plate (22) against which it is pressed increases with increasing pressure on the tip of the needle.

Figure 11 shows the elastic deformation of a rounded surface (21) into a substantially planar surface (21') when applied with sufficient pressure to an opposing planar surface. There is. In this case, the resistance of the FSR transducer (26) is a function of the contact area of the pressure applied on the needle tip (ie, the elasticity of the plunger material).

FIG. 12 shows that a layer (100) of a thin sheet of flexible material, e.g. silver or other metal, on which the dome (102) forms, e.g. a refill interface plug (12). 2 shows another embodiment of a pressure transducer positioned between the plunger (20);

The dome (102) has a planar annular portion (
106). A predetermined pressing force is applied to the refill interface plug (12) and the plunger (
20), when applied to the dome, the dome undergoes reversible collapse. The metal dome is designed to bubble at a pressure substantially equal to the pressure that allows processing of data from the needle, as described above.

The snapping action that occurs during collapse of the dome is detectable by the user of the needle and provides constant tactile feedback to the user indicating that the digitizing device has been switched from a disabled state to an enabled state.

When pressure is removed from the tip of the needle, the dome.

It enters the next ready state and snaps back to its original, undeformed state.

FIG. 13 shows another embodiment of a pressure responsive transducer according to the invention. The transducer includes a pair of electrodes (1,04);
This electrode can be connected, for example, to each inner barrel plug (4
6) on a planar radial surface (58).

These electrodes (104) can be formed as an ink layer on a fold of a flexible plate of the type already described. These electrodes (104) are (not shown)
It is electrically connected to individual terminals, which in turn are connected to respective terminals of the cable assembly.

As in the embodiment shown in Figure 12, the layer (1) is made of silver or other metal and includes a dome (102) and an annular portion (106).
00), the concave surface of the dome is electric w! , (104). Movable plunger (20
) moves towards the inner barrel plug (46), the dome (102) collapses and a dome of conductive metal or other conductive material is brought into contact with the electrode (104).

This bridges the gap between the electrodes (104), thus completing the current path between the electrodes.

When the pressure on the needle tip is released, the movable plunger (20) separates from the inner barrel plug (36) and the collapsed dome (102) elastically recovers to its original shape.

The preferred embodiments described above are presented for illustrative purposes only and are not intended to limit the scope of the invention as defined by the claims. Modifications will readily occur to those skilled in the art without departing from the spirit and scope of the inventive concepts disclosed herein.

[Brief explanation of drawings]

FIG. 1 is a partial longitudinal cross-sectional view of an assembled needle according to a preferred embodiment of the present invention. FIG. 2 is a side view of the pen refill included in the first illustrated needle. Figure 3 shows the inner barrel built into the needle shown in Figure 1.
FIG. 3 is a partial longitudinal cross-sectional view of the assembly. 4 is a cross-sectional view taken along the Z--Z cross-sectional line in FIG. 1. FIG. Figure 5B shows the refill interface shown in Figure 3.
Figures 5A and 5C are each an end view of the refill interface plug of Figure 58; 6B is a longitudinal cross-sectional view of the inner barrel plug shown in FIG. 3, and FIGS. 6A and 6c are respective end views of the inner barrel plug of FIG. 6B. 7B is a longitudinal cross-sectional view of the inner barrel shown in FIG. 3, and FIGS. 7A and 7c are respective views of the inner barrel shown in FIG.
FIG. 3 is an end view of the inner barrel shown in the figures. 8 is a side view of the enclosed flexible plate introduced into the needle of FIG. 1; FIG. 9 is a view of the flexible plate of FIG. 8 in an unenclosed condition; FIG. FIG. 1O is a graphical representation of the measured variation in resistance of an FSR transducer as a function of pressure for three different sample needles. FIG. 11 is a diagram of the refill interface plug and rounded resilient plunger introduced in the second embodiment of the invention. FIG. 12 is a longitudinal cross-sectional view of the refill interface plug, membrane switch and plunger introduced in a third embodiment of the present invention. FIG. 13 is a longitudinal cross-sectional view of the inner barrel plug, membrane switch and plunger introduced in a fourth embodiment of the invention. (1) Needle (2) Pen refilling part (3)
Plastic cap (4) Inner barrel protrusion (6) Nose cap (
8) Washer (10) Inner barrel (12)
Plug (14) Rib (15) Hole
(16) Base (18) Radial surface
(20) Plunger (21) Radial end face
(22) Flexible plate (23) Radial plane (24
a) Anode (24b) (24c) (24h) Conductive connection part (24d) (24e) Terminal (24f)
(24g) Electrode (26) FSR converter (2
8a) Rectangular part (28b) Neck part (28a
) Polygonal part (28) Curved part (30) Notch (32) Inner barrel axis (34a) (34b) (34c) (34d) Hole part (36) Glaze direction rib (42) Annular shoulder part (4
4) Sleeve part (46) Inner barrel plug (48) Base (50) Hole (52) Flange (54) Sleeve part (56) Axial groove (58) Flat end face (60) Cable
Assembly (62) (62') Terminal (64) Inner barrel assembly (66) (68) Half-off (70) Core spacer tube (72) (72') tlil! One-way protrusion (76) (78) O-ring (80) Outer barrel
(84) End cap (86) Circumferential rib
(88) Finger tab (90) hole (92
) (92') Projection (96) Rib (
100) Layer (102) Dome (104)
Electrode (106) Planar annular partial procedure! δ Nail 11 Correct (Method) July 7, 1988

Claims (20)

[Claims] (1) A needle for use with a digitizer tablet having a working surface, the needle having a tip that presses against the working surface of the digitizer tablet, and an electrical resistance that varies with the amount of compressive force applied to the transducer. a transducer and a pair of electrodes in conductive contact with the transducer and forming an electrical circuit with the variable resistor when the compressive force is applied; a mechanical device transmitting an equal compressive force to the transducer, thereby making the resistance of the transducer a function of the pressure. 2. The needle of claim 1, wherein the transducer includes a layer of conductive ink having a resistance that varies as a function of applied compressive force. 3. Each electrode includes a layer of conductive ink that electrically connects the transducer when the chip is pressed against a working surface of a digitizer tablet. ) needles listed. (4) the layer of conductive ink of the transducer is overlaid on a layer of a first plastic backing, and the layer of conductive ink of the electrode is overlaid on a layer of a second plastic backing; 4. The needle of claim 3, wherein the first and second backing layers are electrically non-conductive. (5) The needle according to claim (4), wherein the backing layer has flexibility. (6) The needle according to claim (4), wherein the backing layer is made of Mylar. (7) the first and second backing layers are connected by a bridge portion, the first and second backing layers and the bridge portion are formed as a single layer of plastic, and the single layer of plastic is connected to the 5. Needle according to claim 4, characterized in that it is folded by a bridge section. (8) a mechanical device for transmitting a force is formed to apply said compressive force to the ink layer of the transducer over increasing areas as the compressive force increases; Needle according to claim 3, characterized in that the resistance depends on the magnitude of the compressive force and on the area of the transducer and the ink layer to which the force is applied. (9) The mechanical device includes a portion having a bulbous end made of a resilient material that contacts and applies a compressive force to the transducer in response to the pressing of the tip against the working surface of the tablet. A needle according to claim 8, characterized in that: (10) comprising a dome-shaped thin flexible material, the dome being subject to reversible collapse when pressure is applied on the dome, the dome being between a first portion and a second portion of the mechanical device; 2. A needle according to claim 1, wherein the mechanical device transmits a compressive force to the transducer by acting on and collapsing the dome. (11) the mechanical device comprises a sleeve-shaped casing having an axis; and a support device fixedly arranged relative to the casing and having a first planar surface transverse to the axis of the casing; a pressing device movable in an axial direction relative to a casing and having a second planar surface transverse to the axis of the casing, the first and second planar surfaces being arranged oppositely; A needle according to claim 1, characterized in that the transducer and the electrode are sandwiched between the first and second planar surfaces. (12) a needle for use with a digitizer tablet having a working surface, the tip being pressed against the working surface of the digitizer tablet; said switch device to change from said predetermined compressive force to a second state; A needle for use with a digitizer tablet, characterized in that it has a working surface consisting of a mechanical device adapted to change in response to pressure exceeding . (13) The switching device includes a pair of electrical contacts and a conductive bridge, and when the pressure exceeds a predetermined compressive force, the mechanical device electrically connects the conductive bridge to the pair of contacts. The needle according to claim 12, characterized in that the needle is adapted to be brought into contact. 14. The needle of claim 13, wherein the switch device comprises a flexible plastic sheet, and the pair of electrical contacts are applied to one side of the sheet. (15) a conductive bridge includes a thin layer of conductive material in a dome shape, the dome undergoing reversible folding when a predetermined compressive force is applied to the dome;
wherein the dome is mounted between a mechanical device and a pair of electrical contacts, the mechanical device being adapted to close the switch by applying the predetermined compressive force to the dome. The needle according to claim (14). (16) A needle for use with a digitizer tablet having a working surface and a first electrode, the needle having a sleeve-shaped casing having an axis, protruding from an end of the casing and pressing against the working surface of the digitizer tablet. a chip; an anode that can be capacitively connected to the first electrode of the digitizer tablet; and for emitting a signal generated during the capacitive connection of the anode.
a terminal electrically connected to the anode, and a thin substrate made of a flexible material and enclosed inside the casing;
Needle, characterized in that said anode and said terminal are applied on said thin substrate. (17) a transducer having an electrical resistance that varies depending on the magnitude of a compressive force applied to the transducer; and a pair of electrodes in conductive contact with the transducer during application of the compressive force; a mechanical device for transmitting to said transducer a compressive force approximately equal to the pressure being exerted by the tip on the working surface of the tablet, and for making the resistance of said transducer a function of said pressure; said transducer and said electrode; Needle according to claim 16, characterized in that a pair of are each applied on said thin substrate. (18) a transducer comprising a layer of conductive ink having a resistance that varies as a function of an applied compressive force, the electrodes each comprising a layer of conductive ink, the transducer disposed on the first portion of the substrate; formed, the electrode is formed on a second portion of the substrate, the anode is formed on a third portion of the substrate, and the first and second portions are connected by a fourth portion of the substrate. 18. The needle according to claim 17, wherein the base material is folded at the fourth portion. (19) a pen refill and an inner barrel in which the pen refill is arranged, a tip of the refill serving as the tip of a needle, and a mechanical device that is a part of the pen refill; A needle according to claim 17, characterized in that the fourth portion of the substrate is adapted to be wrapped around the inner barrel. (20) a support device having a first planar surface arranged fixedly relative to the casing and transverse to the axis of the casing, the mechanical device being arranged relative to the casing; and a second planar surface in a direction transverse to the axis of the casing, the first and second planar surfaces being arranged oppositely. 18. A needle according to claim 17, characterized in that the transducer and the electrode are sandwiched between the first and second planar surfaces.