JPS60175401A - Pressure sensitive conductive element - 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] (b) Technical field The present invention relates to a polymeric pressure-sensitive conductive element.

←) Prior art In recent years, the electronic industry has been rapidly developing. In the electronics industry, sound, stress (strain), temperature (including heat), pressure, electricity, electromagnetic waves (light, ultraviolet rays).

Input physical information (energy) such as There is an increasing need for information conversion (detection, conversion, recording, storage, and output) of combinations of information.Functional organic materials with information conversion ability are used as materials used in these fields. 〇The "pressure-sensitive conductive element" referred to in the present invention means that when pressure is applied in the film thickness direction, the resistance value of the film between the front and back surfaces corresponds to the pressure value through the film. It means an element whose resistance value changes and outputs to the outside through a circuit on the surface of the film.However, when no pressure is applied at all, the specific resistance value in the film thickness direction is 1,
06Ω・α or more and has no conductivity. Moreover, when the pressure is removed after processing, the film again shows the resistance value before pressurization. In addition, "having electrical conductivity" or "exhibiting electrical conductivity" means that the specific resistance value of the material is smaller than 1060 α, and "having no electrical conductivity" means that the specific resistance value of the material is smaller than 1060 α. This means that the value is 106Ω·α or more.

In addition, in this description, the "film surface direction" means the direction shown by arrow A in the attached FIG. 1, and the "film thickness direction" means the direction already shown by the arrow in the same figure.

"Inside the film" and "inside the film" refer to the entire part inward from the front and back surfaces of the film by a film thickness of 10 nm, respectively, and are the C portion in the thickness cross section in FIG.

The term "front and back surfaces of the film" refers to all parts within a film thickness of 10 nm from the front and back surfaces of the film, respectively, and corresponds to part e in the thickness cross section in FIG. "Layers of each film surface thickness" in the film refer to the respective film thicknesses when the inside of the film is divided into 10 equal parts in the film thickness direction, that is, the film thickness layer indicated by f in the thickness cross section in Figure 1. means. Furthermore, in the text, "maximum value and exhibiting maximum" means that the pore diameter takes the maximum value in the minute portions before and after the line point.

A rubber conductive film is known as a pressure-sensitive conductive film. This is 27 grains of car in the rubber! It is a film in which r is dispersed, and in order to make this film conductive, it needs to have a thickness of at least one layer, and this film also has conductivity in the direction of the film surface. (c) Object of the invention An object of the invention is to provide a novel pressure-sensitive conductive element made of a conductive porous membrane that has an excellent resolution that cannot be achieved with conventional membranes in terms of the ability to detect all pressure-loaded locations.

B) Structure of the Invention The pressure-sensitive conductive element according to the present invention has (1) conductivity only between two points within a circular area with a radius of 05 mm centered on an arbitrary point in the same plane in the film surface direction; , and (2) When pressure is applied in the film thickness direction, there is conductivity only between the load point and points within a circular area with a radius of 0.5WI around the load point, and the film thickness It is composed of a porous membrane whose specific resistance value in the direction changes according to changes in pressure, and a wire with a thickness of 0.5 mm or less made of a conductive material is formed on at least one of the front and back surfaces of this membrane. The electric circuit is characterized in that the electric circuit has a plurality of terminals for connection to an external electric circuit.

(E) Specific description of the structure of the invention The first feature of the pressure-sensitive conductive element of the present invention is that the pressure-sensitive conductor'FIL
In the direction of the membrane surface of the porous membrane constituting the element, there is a gap between any point within a circular area with a radius of 0.5 am9 centered on the point to which pressure is applied (hereinafter referred to as "load stroke") and the load point. On the other hand, in the film thickness direction, conductivity exists only between the load point and a point within a circular area with a radius of 0.5 mm around the load point. By having conductivity only within a limited range of points within a circular area with a radius of 0.5 around the load point, it is possible to absorb the pressure received on one side with an accuracy within a radius of 0.5 m. It can be conveyed on one side. The smaller the accuracy expressed by this radius, the better. However, even if the precision of the porous membrane is reduced, the resolution of the pressure-sensitive conductive element will not improve unless the resolution of the electric circuit on the surface of the porous membrane is adapted to this precision. Therefore, the range exhibiting conductivity around the load point is preferably within a circular region with a radius of 0.01 to 0.3 m+. Here, "having conductivity only within a circular region with a radius of 0.5 mm centered on the load point in the film surface direction" means that the following two conditions are satisfied.

That is, two terminals for measuring electrical resistance, each having a needle-like tip, are crimped on the front and back surfaces of a porous film constituting a pressure-sensitive conductive element.
When the distance between the centers of the tips of both crimp terminals is 0.5 fins or less, the specific resistance value when If it is large, the specific resistance value will be 106 Ω or more.
When crimped to a point, if the distance between both crimp terminals is 0.5 m or less, the specific resistance value between both terminals is 10 Ω・-υ smaller, and if it is 0.5 + ma υ larger, the specific resistance value is 10
Indicates 6Ω・crn or more.

A second feature of the present invention is that when pressure is applied in a direction perpendicular to the membrane surface of the porous membrane, the specific resistance value of the porous membrane in the thickness direction changes. By changing the specific resistance value in the film thickness direction in response to changes in the load pressure, changes in the pressure received on the membrane surface can be converted into changes in the resistance value.

A third feature of the present invention is that at least one of the front and back surfaces of the porous membrane is made of a conductive material and has a thickness of 0.5 sm.
It has an electric circuit consisting of the following wires and a plurality of terminals for connecting the electric circuit to other electric circuits. By drawing an electric circuit optimal for the desired pressure detection on at least one of the front and back surfaces of the porous membrane,
It is possible to have a position detection resolution of +o+.

Examples of the electric circuit include those having a position detection function in the form of a square grid, and those in the form of a switch, but the form is not particularly limited, and any form may be used. Resolution of detection of load point position ”k O, 5
To achieve trm, the thickness of the conductor constituting the electric circuit must be 0.
Must be in the fifth key or below. The conductor constituting the electric circuit is preferably made of a mixture of an organic polymer substance and a conductive inorganic substance. In this mixture, it is desirable that the conductive inorganic substance is dispersed in the form of fine particles, and the mixing ratio is desirably that the weight ratio of the inorganic substance to the organic polymeric substance is 40 or less. Organic polymer materials have excellent flexibility and can deform in response to the deformation of the porous membrane when pressure is applied.

Therefore, it provides stable electrical characteristics against repeated deformation. As the organic polymer material, various rubbers, particularly silicone rubbers, are desirable because of their ease of deformation. Suitable conductive materials include noble metals such as silver, platinum, and gold, and fine powders (for example, fine powders with a diameter of about 10 μm) of graphite, copper, and the like. Among them, graphite and copper are economically advantageous. By drawing thousands of electric circuits made of conductive material on each of the front and back surfaces of the membrane, it is possible to provide a variety of input and output formats as a pressure-sensitive conductive element. For example, it can be used as a pressure switch, for a graphic tablet, or as a pressure sensor. Furthermore, even if one membrane surface has an electric circuit and the other surface is completely covered with a conductive substance, the pressure-sensitive conductive element can be given a function for graphic tablet left use. .

The terminal may be of any material as long as it has conductivity to accurately transmit current fluctuations caused by changes in resistance between the membranes to other electrical circuits, but platinum wire, platinum wire, etc.
Examples include copper wire. The number of terminals should be at least two to measure the resistance on the front and back surfaces of the membrane, and the amount of information you want to obtain (
For example, the number can be increased by considering the difference between the top, bottom, left and right, or the difference between each circuit.

The external electrical circuit connected to this pressure-sensitive conductive element is as follows:
Any circuit that can sense changes in resistance, voltage, and current between membranes may be used, such as a circuit that combines an AC power supply and a universal resistance measuring device.

The film thickness d of the pressure-sensitive conductive element of the present invention is determined to suit the required mechanical properties, but the smaller the better in order to reduce the voltage drop in the film. Usually 1μm~5
ms is preferably 10 μm to 10 μm. Film thickness d of the element
The device was cut with a razor and its cross section was JEOL Ltd.
It can be observed and measured using SM-U3 model.

As a porous film, it has conductivity only between two points in a circular region with a radius of 0.5+ nm centered on any point in the same plane in the film surface direction, and pressure is not applied in the film thickness direction. In this case, there is conductivity only between the load point and a point within a circular area with a radius of 0.5 ft around the entire center of the load point,
The specific resistance value in the film thickness direction may be any value as long as it changes in response to changes in pressure. A practically preferable membrane has a through hole in the membrane that reaches both the front and back sides, and when focusing on any one hole, the hole that directly communicates with this hole is in the layer of each membrane surface thickness within the membrane. is located in an annular region within the circumferential radius Q of the pore within 5 m in the membrane surface direction, and when the diameter of the wire pore changes in the film thickness direction, a maximum value exists inside the membrane, and the conductive material is An example is a porous polymer membrane that is sealed in a portion where the internal pore size shows a maximum value. In such a porous polymer membrane, the average pore half and diameter (D/
2) is 0.5 μm or less and D/2 on at least one side
is 0.005 μm or more, and the pore size inside the membrane is less than 0.5 μm in the maximum part.
It is desirable to keep it.

The existence of through holes having a maximum value in the film thickness direction with respect to the hole radius is confirmed by the following method. First, a membrane with nothing sealed inside (weight 1!tW+) is immersed in a mercury medium in a vacuum (10-2+mHg or less). Next, the mercury medium was
After pressurizing under atmospheric pressure and then removing the pressure at atmospheric pressure, the wire membrane was taken out and when observed with the naked eye, it appeared black, and when the weight (Wz) of the wire membrane was measured after pressure was removed, W, > Wt. From this, it can be confirmed that mercury remains encapsulated in the maximum part of the pore radius. Further, the average pore radius and number of pores in the maximum portion can be measured by cutting out a thin film from the porous membrane in this portion and directly observing it with an optical microscope.

The number of maximum parts can be determined by converting the enlargement magnification of the photograph of the above-mentioned thin film sample observed with an optical microscope.
A straight line with a length corresponding to 100 μm is drawn along the film thickness direction of the sample, and the number of intersections of the maximum portion with the straight line is counted.

The amount of the conductive substance sealed in the pressure-sensitive conductive porous membrane of the present invention is determined to suit the applied pressure and membrane thickness, but usually the volume ratio occupying the pores of the porous membrane of the support is 10. ~80
H, preferably 50 to 80 H. The volume ratio of the conductive substance occupying the pores of this porous membrane is (Wz Wt)
It is given by 10'/(ρ・■・Pre)(chi). Here, ρ is the density of mercury, ■ is the volume of the porous membrane used as the support (crn3), and Pre is the in-plane porosity. Also,
The average pore radius of the maximum part is larger than 0.005 μm and 0
．． Less than 5 sides, preferably 0.01μm or more 0.5
less than fi. In addition, the conductivity is better as the number of maximum portions' increases, but in order to improve the resolution of the pressure-sensitive area, which is usually 1 to 104 pieces/100 μm, it is preferably 1 to 105 pieces/1.
00 μm.

On the front and back surfaces of the membrane, pores with an average pore radius of 5 nm or more and 0.5 μm or less are present per 1 crn2 (D).
The unit of ctn is preferably 5×10 4 /D or more, and it is desirable that the number be present at a ratio of 5×10 4 /D or less, since this increases the mechanical strength of the film and increases the number of pressure-sensitive terminals, thereby improving resolution.

If the pore diameter ratio between the front and back surfaces of the porous membrane is 10 or more, even if the load pressure is the same, the resistance value will be significantly different depending on the direction in which the front and back forces 1 are applied to the wire membrane.

When pressure is applied from the surface of the membrane with smaller pores, the conductive substance inside tends to move to the other surface with larger pores, making it easier to obtain conductivity. On the other hand, if pressure is applied from the side with the larger pore diameter, the conductive substance inside will be less likely to move toward the smaller pore diameter. Therefore, depending on the working pressure, expected conductivity, and other conditions of the wire membrane, the direction in which it is used is determined from the front and back sides.

Further, the conductive material means a material having a specific resistance value of 100 or less, and may be either solid or liquid at room temperature.

However, when the conductive substance is a liquid, the contact angle between the material constituting the porous polymer membrane and the conductive substance must be 90° or more. If the conductive substance is solid at room temperature, it is desirable to make it into a solution using an organic solvent or the like. Specific examples of conductive substances include mercury, wood metal, silver paste,
Copper paste or a solution of Li cto 4 in dimethylformamide is available.

The materials forming the porous membrane are cellulose, regenerated cellulose,
Hydrophilic materials such as cellulose nitrate, collodion, and cellulose acetate, or polyethylene, polyzolopyrene, and polystyrene+! '') Any hydrophobic material such as ester, Teflon, silicone, nylon, etc. is preferable.Regenerated cellulose is particularly preferred from the viewpoint of membrane strength, ease of controlling pore size, and resistance to organic solvents.

The pressure-sensitive conductive element of the present invention is for soft switches.

It can be used for electronic industry, graphic tablets, etc.

The pressure-sensitive conductive element of the present invention can be produced, for example, by the following method. 6% by weight cellulose copper ammonia solution at 30℃
The acetone concentration in the acetone vapor atmosphere is 8
It was cast onto a glass plate at a speed of 0.2 m/min using an applicator with a thickness of 500 μm in an atmosphere of zero concentration, and was left in the atmosphere for 8 minutes to cause microphase separation and to form a film with a dilute phase. After confirming that no leaching had occurred on the surface, the obtained cast film was placed in a mixed solution with an acetone/water ratio of 33.6% by weight, an ammonia/water ratio of O, and an amount of S1 (2
0°C) for 60 minutes in a horizontal position. After that, 20℃
After immersing in a 2 wt% sulfuric acid aqueous solution for 15 minutes, rinsing with water, then blotting with paper with a water content of 'kF', and soaking in acetone (10
A flat membrane can be obtained by immersing the membrane in 0iW quantity (1) for 15 minutes, replacing all the water in the membrane with acetone, sandwiching it between F paper and air-drying it at 30°C.

A porous membrane is obtained by immersing this flat membrane in a mercury medium in a vacuum (10 wnHg or less), pressurizing the mercury medium to 300 atm, then removing the pressure under atmospheric pressure and taking it out from the mercury medium. . A 2 m square grid is drawn on the surface of this porous membrane with conductive silicone ink, and conductive silicone ink is applied all over the back surface.

The pressure-sensitive conductive element of the present invention can be produced by connecting two platinum wire terminals to each of the conductive silicon ink layers on the front and back sides. However, prior to the examples, methods for measuring various physical property values used in the detailed description of the invention are shown below.

Average pore radius r3@r4 on the front and back surfaces of the membrane. Number of pores N, and in-plane porosity Pre: Number of pores in which the medium diameter of pores per 1 crn2 of porous membrane is r−r+dr, expressed as 1N(r)dr (N(r) is the pore radius distribution function ), average pore radius 'Fs t r4 t 1
Number of pores per “crn” N1 and in-plane porosity Pre L
ri are expressed by equations (1), (2), (3), and (
4) Given by Eq.

Pre=rcf'''r2N(r)drXloo (匍
(4) Also, the average hole radius D/2 is D/2 = (F3・
It is defined in 14 cases. A scanning electron microscope, model JSM-U 3 manufactured by JEOL Ltd., is used to take electron micrographs of the front and back surfaces. From the photograph, the pore radius distribution function N(
r) Calculate k and substitute it into equations (1) to (4) in the text. That is, a scanning electron micrograph of the part where the pore radius distribution function is desired is taken to an appropriate size, for example, 20 cm x
20 cm ) K enlarged and printed, and 20 test lines (straight lines) were drawn at equal intervals on the obtained photograph. Each straight line crosses a number of holes. Measure the length of the straight line that exists within the hole when it crosses the hole, and calculate this frequency distribution function. Using this frequency distribution function, for example, stereology (
For example, using the method of Norio Suwa, Determined Mouse Morphology, Iwanami Shoten)
(r)f: Determine. The average hole radius r3+r4 is N(r)e
Using equations (1) and (2), the number of pores N is calculated using equation (3) using N(r), and the in-plane porosity Pre is calculated using equation (4) using N(r)f: Calculated.

Example 1 Cellulose linter (average molecular weight 2.33×10”)
6% by weight in a copper ammonia solution prepared by a known method.
After dissolving the solution at a concentration of 70° C., the solution was cast onto a glass plate at a speed of 0.2 m/min with an applicator having a thickness of 500 μm in an acetone vapor atmosphere at a temperature of 30° C. and a saturated vapor pressure of 70° C. The cast film was left in this atmosphere for 8 minutes to confirm that microphase separation had occurred and that no dilute phase had oozed out onto the membrane surface, and the resulting cast film had an acetone/water ratio of 33.6% by weight. The sample was immersed horizontally for 60 minutes in a mixed solution (20° C.) with an ammonia/water ratio of 0.8% by weight. After that, it was immersed in a 2% sulfuric acid aqueous solution at 20°C for 15 minutes, washed with water, absorbed the moisture with 'tF paper, and immersed in acetone (100% weight) at 20°C for 15 minutes to replace the water in the membrane with acetone. The resulting membranes were sandwiched between p paper and air-dried at 30°C.The resulting membranes were each immersed in a mercury silver paste pL1Ct04/DMF medium in vacuum (10 mmHg or less), and the medium was pressurized to 300 atmospheres. Next, the pressure was removed under atmospheric pressure to remove the porous membrane from the medium.On the surface of this porous membrane, an electric circuit was formed as shown in Figure 2 (top view) and Figure 3 (cross-sectional view). That is, conductive silicone ink (conductive ink XE14-322 manufactured by Toshiba Silicon) was applied to the surface of the porous membrane 1 on 2 gauze paper with a thickness of 0.3 yt.
Draw an aa grid (2) and apply conductive silicone ink (3) all over the back side. Four platinum wire terminals were connected to the front surface and one platinum wire terminal to the back surface in the conductive silicon ink layers on the front and back surfaces, respectively.

Example 2 The flat membrane prepared in Example 1 was immersed in the conductive silicone ink of Example 1 diluted with 100 parts by weight of toluene,
The silicone medium was pressurized to 300 atmospheres. Next 1
The pressure was removed under atmospheric pressure and the wire film was taken out from the medium. After that, it was dried in a dryer at 150°C for 1 minute, and a circuit was drawn on the front and back sides of the line film with conductive silicone ink in the same manner as in Example 1.
Platinum wire terminals were respectively connected to the silicon ink layer.

Comparative Example 1 Circuits were drawn on the front and back surfaces of commercially available pressure-sensitive conductive rubber (manufactured by Japan Synthetic Rubber Co., Ltd.) using conductive silicone ink in the same manner as in Example 1, and platinum wire terminals were connected to the silicone ink layers, respectively.

Using the pressure-sensitive conductive element of this comparative example and the pressure-sensitive conductive element listed in Example 1, assuming use in a graphic tablet,
Four points were input on the element, and it was examined whether the positions of the three points could be identified by the difference in resistance value. Figure 2 is a plan view of the pressure-sensitive conductive element fabricated in Example 1. (1) is the pressure-sensitive conductive porous membrane, (2) is the surface circuit drawn with conductive paint, and (25 is the terminal part drawn with conductive paint. Figure 3 shows this pressure-sensitive conductive element. (1), (2), (2m) are the same as FIG. 2, and (3) is the conductive paint layer on the back side.

FIG. 4 is a plan view of an element for a graphic tablet using the pressure-sensitive conductive element of the present invention, in which (4) shows an ammeter, (5) shows a constant voltage power supply, and (6) shows a platinum wire terminal. FIG. 5 is a cross-sectional view of the graphic tablet element shown in FIG. 4. Tab p1 On the edge of the circuit (2) on the surface of the element, there are terminal parts (2 pieces) drawn with the same conductive silicone ink in each of the four directions (up, down, left and right), and one platinum wire terminal (6 stripes) drawn on each side. It is connected in parallel to the conductive paint surface (3) on the back side via an ammeter (4) and a power source (5).

FIG. 6 shows an example of use of the graphic tablet element shown in FIGS. 4 and 5. FIG. In FIG. 6, (7) shows a constant pressure pen used for input, and this figure shows input using the pen. When one point is input with a predetermined pen 7, conductivity occurs between the membranes and current flows. FIG. 7 schematically shows how the current flows. Break 1 here
M indicates the flow of current. In Figure 7, when inputting to point A, there is conductivity on the front and back of the membrane only between the points in a circle with a radius of 0.5 squares around point A, and the circuit that was in contact with this point (
February - Electric current runs through everything. The current value of the entire circuit is as shown by the broken line in the figure.Xl +X2 +yI tyz
Measure in the direction of Next, if you input to a point other than A, that is, if the input position changes, xI.

Xl F)'1 tyz kThe value of the flowing current changes according to the change in the length of the circuit. This takes advantage of the fact that when there are many circuits through which current can flow, it flows preferentially to the circuit with the least resistance, that is, the circuit with the shortest distance in this circuit. Furthermore, since the current value changes depending on the degree of input pressure even at the same position, the strength of the force can also be detected.

In other words, the input position is xl ・Xl *71 p
Depending on the current ratio in the four directions of Y2, the strength of the input is xt T
It can be detected by the current value of Xl 1 yl t '12.

Table 1 listed below shows the load pressure of 10 at each point A, B, C, and D.
0 K97cm" XI t Xl + y
A typical example in which the current value of l tyz was measured for the pressure-sensitive conductive element of Example 1 and the pressure-sensitive conductive element of Comparative Example 1 is shown. Points A, B, C, and D are adjacent to each other at intervals of 4III+11. According to Table 1, there is a significant difference in the current values at the four points in the pressure-sensitive conductive element of Example 1, whereas in the pressure-sensitive conductive element in Comparative Example 1, there is a clear difference in the current values at the four points. Not. That is, the four points cannot be clearly identified in the element of Comparative Example 1, whereas the four points can be clearly identified in the element of Example 1. This is because the pressure-sensitive conductive porous film used in the pressure-sensitive conductive element of Example 1 has conductivity only within a circle with a radius of 0.5 mm in the film surface direction, that is, the resolution is 0.5 mm in radius.
This is due to the fact that it is within the mR circle.

Margin below

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing terms used when describing the pressure-sensitive conductive element of the present invention. FIG. 2 is a schematic diagram (plan view) showing an example of the electrical circuit on the membrane surface of the pressure-sensitive conductive element of the present invention, and FIG. 3 is a cross-sectional view of the pressure-sensitive conductive element shown in FIG. 2. FIG. 4 is a plan view of an element for a graphic tablet using the pressure-sensitive conductive element of the present invention, and FIG. 5 is a cross-sectional view of the element shown in FIG. 4. FIG. 6 is a schematic diagram showing how input is made to the graphic tablet element shown in FIGS. 4 and 5, and FIG. Measure all current values flowing in four directions. Throughout each figure, a... membrane surface direction, b... 1 thickness direction, C... inside and inside the membrane, d... film thickness, e... undressing back side, f... membrane 1... Pressure-sensitive conductive porous membrane, 2... Surface circuit drawn with conductive IL paint, 2'... Terminal portion drawn with conductive paint, 3 ... Conductive paint layer, 4... Current 1i1.5... Constant voltage power supply,
6... Platinum wire terminal, 7... Constant pressure pen used for input, A, B, C, D... Input points. Patent Applicant: Asahi Kasei Kogyo Co., Ltd. Patent Attorney Akira Aoki Patent Attorney Kazuyuki Nishidate Patent Attorney Yukio Uchida Patent Attorney Akira Yamaguchi Patent Attorney Masaya Nishiyama 1st 2nd 4th 1 Houki 5 View 1. 7 same

Claims (1)

[Claims] 1. A porous film that satisfies the following requirements (1) and (2), and at least one of the front and back surfaces of the wire film is made of a conductive material and has a thickness Q, 5 + a A pressure-sensitive conductive element characterized by having an electric circuit consisting of the following wires and having a plurality of terminals for connecting the electric circuit to an external electric circuit: (1) Direction of the film surface of the wire film. , there is conductivity only between two points within a circular area with a radius of 0.5+mm centered on an arbitrary point in the same plane. (2) When pressure is applied in the thickness direction of the wire film, the load It has conductivity only between a point and a point within a circular area of half and 0.5 mm around the load point, and its specific resistance value in the film thickness direction changes according to changes in pressure. 2. The pressure-sensitive conductive element according to claim 1, wherein the conductive substance is composed of a mixture of an organic polymer substance and a conductive inorganic substance. 3. Claim 1 2. The pressure-sensitive conductive element according to claim 1 or 2, characterized in that the porous membrane has a circuit made of a conductive material on both sides of the porous membrane. 4. The porous membrane is made of regenerated cellulose material. A pressure-sensitive conductive element according to claim 1, 2, or 3, characterized in that: