JPH02193030A - Pressure detector - 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] [Technical Field] The present invention relates to a pressure detection element, and more specifically, the present invention relates to a pressure detection element that utilizes the property that the resistance value decreases as pressure is applied (a = R-1). Regarding pressure sensors.

[Prior art]

Pressure sensors (pressure detection elements) are used everywhere not only to determine the level of pressure being measured, but also to detect the contact surface or contact length.

For example, as shown in FIG. 7, a typical conventional pressure sensor is a plastic film 11.1.
2, upper and lower electrodes 21 and 22 are printed with ink containing metal powder (silver, copper, etc.) or carbon ink, a pressure-sensitive conductive layer 31 is provided on one of the electrodes, and this upper and lower electrode is connected to the electrode 22 and the pressure-sensitive conductive layer. 31 is known, which has a structure in which they are bonded together using double-sided adhesive tape 5 with a gap between them.

However, these pressure sensors (i) may be subject to deformation of the pressure-sensitive conductive layer in a high-pressure environment, causing the 1m pole to stick together and take time to recover (hysteresis characteristics are not good); (...) in a high-temperature environment; (i) There may be interference between adjacent electrodes and no difference in pressure level may occur, resulting in electrodes sticking together and being damaged without returning The first problem is that the position cannot be detected accurately.

〔the purpose〕

The first object of the present invention is to solve the above problems,
A second object of the present invention is to provide a pressure sensing element that can be easily used repeatedly.A second object of the present invention is to provide a sensor that can accurately detect pressure.

〔composition〕

The pressure sensing element of the present invention is characterized in that a pressure sensitive conductive layer is sandwiched between two electrode sheets and laminated.

Incidentally, the present inventor has confirmed that the above defects can be eliminated by providing an electrode separation member between the two electrode sheets or by forming irregularities on the inner surface of at least one of the electrode sheets. The present invention has been achieved thereby.

In the following, the invention will be explained in more detail with reference to the accompanying drawings. FIG. 1 shows three typical cross sections of the pressure sensor of the present invention.

FIG. 6 shows a schematic cross section of another example of the pressure sensor of the present invention.

First, the explanation will start from the type in which the pressure-sensitive conductive layer contains or has an electrode separation member on the surface (FIGS. 1, 2, and 3).

The electrode sheet includes a metal sheet 1a [Fig. 2 (a)], a resin film containing a conductive agent (metal powder, conductive carbon, etc.) 1b [Fig. 2 (b)], and a resin film containing a conductive agent (metal powder, conductive carbon, etc.). An IC with electrodes formed thereon [FIG. 2 (c)] can be considered. Among them, the electrode sheet IC of the type shown in Fig. 2 (c)
is desirable for creating a wide variety of pressure sensors. Although the material of the resin film in FIGS. 2(b) and 2(c) is not specified, polyamide-imide is a typical example.

The electrode 21 (or 22) in the electrode sheet IC of the type shown in FIG. 2(c) is a vapor-deposited layer of metal (copper, etc.) or a metal foil, or preferably a patterned version of these. Further, the electrode 21 (or 22) may be printed with conductive ink. Electrode 21 (
or 22), by providing a metal vapor deposition layer on the resin film 11 (or 12) and subjecting it to a pattern etching method, or by using conductive ink, for example. It can be formed by screen printing or the like. On the other hand, the electrode 21 (or 22)
If it is solid, the resin film 11 (or 12
) can be provided by forming a metal vapor deposited layer thereon, by adhering a metal foil using an adhesive, by solid printing with conductive ink, or the like.

Electrode sheets la and lb in the pressure sensor of the present invention.

Of course, 1c may be used in an appropriate combination of these.

In the example shown in FIG. 1(a), an electrode sheet 1a made of a metal sheet and an electrode sheet 1c in which electrodes 22 are formed on a plastic sheet 12 are used. The conductive layers 31 are sandwiched and laminated. As the electrode separation member 4 here, an insulating and elastic material such as a silicone rubber ball is used, but as will be described later, it is not limited to this.On the other hand, as the pressure-sensitive conductive layer 31 Pressure-sensitive conductive rubber is generally used.

In the example shown in FIG. 1(b), two electrode sheets 1c are made by coating carbon on patterned electrodes 21.22 on a resin film 11.12, and a pressure-sensitive conductive layer is formed between them. 31 is formed by coating, and the electrode separation member 4 is arranged so as to be in contact with the pressure-sensitive conductive layer 31.

As shown in FIG. 1 (B), if the electrode separation member 4 is in sheet form, it can be a conductive sheet even if it is an insulating sheet (for example, a silicone rubber sheet with a rubber hardness of 80) as long as it has an elasticity of 1. It doesn't matter if there is.

However, if the electrode separation member 4 in contact with the pressure-sensitive conductive layer 31 is insulative, at least a plurality of openings or continuous/discontinuous voids are provided. The purpose of these holes is to allow the pressure-sensitive conductive layer 31 to contact the electrode 22 through the holes when pressure is applied to the upper and lower electrode sheets. That is, the sheet-like electrode separation member 4 controls the distance between the upper and lower electrode sheets, and at the same time contributes to quick recovery after pressurization.

FIG. 3 is a schematic perspective view of one example of the electrode separation member 4. In FIG. 1, 0 represents an opening or the like. The type shown in FIG. 3(a) is an example that is effective for being present (contained) in the pressure-sensitive conductive layer 31 mentioned above. Figure 3 (b)
Types (c) and (d) are examples in which they may be present in the pressure-sensitive conductive layer 31 or may be disposed in contact with the pressure-sensitive conductive layer 31. Further, the type shown in FIG. 3(e) is suitable for being placed in contact with the pressure-sensitive conductive layer 31, and has a plurality of protrusions made of, for example, shape memory plastic on at least one of its front and back surfaces. 41 is provided, and is most effective for recovery after pressurization when the sensor is used as the electrode separation member 4 in a high temperature environment. That is, this protrusion 41 functions as a spring material and also supports the upper and lower electrode sheets, and the protrusion 41 is made of shape-recording plastic, which is useful for quickly returning the distance between the upper and lower electrode sheets that is shortened by pressure. The same holds true when it is made of silicone rubber instead.

Further, the material of the electrode separation member 4 is not limited to a silicone rubber sheet, and its shape is not limited to that shown in FIG. 3. For example, elastic rubber pipes, corrugated plates, etc. can also be used. Further, the electrode separation member may be conductive or non-conductive.

FIG. 1(C) shows an example in which pressure-sensitive conductive layers 31 and 32 are formed on both sides of a sheet-shaped electrode separation member 4. In comparison with FIG. 1(b), a configuration in which a pressure-sensitive conductive layer 32 is newly provided in contact with the electrode separation member 4 is adopted.

Even in this pressure sensor of FIG. 1(c), the electrode 21.
22 may be a solid pattern (no pattern is formed), but in that case, if the electrode separation member 4 is made of an insulating material, it should have a shape such as an opening or the like. It is preferable to use it in

In the pressure sensor of the present invention, the electrode separation member 4 has no openings etc.
is provided, the openings etc. are filled with the same material as the pressure sensitive conductive layer 31 and/or 32, or the pressure sensitive conductive layer 31 and/or 32 itself is provided with openings etc. Those embedded in 0 can also be used effectively.

According to the pressure sensor of the present invention having such a structure, when a load is applied to the upper and lower electrode sheets, the load is eventually applied to the pressure-sensitive conductive layer 31 and/or 32 between the electrode sheets, Load force can be detected by resistance changes in the pressure-sensitive conductive layers 31 and/or 32.

As a modification of the pressure sensor of the present invention (shown in FIG. 1), when viewed from above, (a) a pattern of electrodes 21 and 22 is provided in rows and in the direction [FIG. 4 (a)];
(b) Holes are provided in the sheet-like electrode separation member 4 at positions that overlap with the patterns of the electrodes 21.22 [Fig. 4 (b)], and in addition, as shown in Fig. 4 (c), One idea is to give a certain regularity to the pattern shape.

Further, one electrode 21 is formed in a diagonally parallel pattern [FIG. 5 (a)], and the other electrode 22 is formed in a vertical pattern [FIG. 5 (b)], and more preferably, Electrode separation member 4 [
A pressure sensor can also be made by combining the components shown in FIG. 5 (c)].

Comparing the pressure sensor shown in FIG. 1(B) and the pressure sensor shown in FIG. 1(C), the latter has pressure-sensitive conductive layers 31 and 32 formed on both sides with the electrode separation member 4 in between. Measurements can be made with high sensitivity.

Next, a description will be given of the pressure sensor of the present invention shown in FIG. 6, in which the electrode separation member and the electrode sheet are substantially integrated.The materials described above can be applied as they are. Here, one electrode sheet 1d is connected to the other electrode 1
An electrode 23 is provided on the side of the mating surface with e, or in a concave portion of the resin sheet 13 having regular irregularities formed therein. The other electrode sheet 1e has an electrode 21 provided on a resin film 11, and has the same structure as that shown in FIG. 2(c). The tip of the convex portion of the electrode sheet 1d is in contact with the electrode 21 of the electrode sheet 1e, and
The space between the electrodes 23 and 21 is filled with a pressure-sensitive conductive agent to form a pressure-sensitive conductive layer 33 .

In this type of pressure sensor of the present invention, the convex portion of the resin sheet 13 plays the same role as the electrode separation member explained in FIGS. 1 and 3. This is due to the elastic restoring force of the resin sheet itself. It originates from. Therefore, this sixth
In the pressure sensor of the present invention shown in the figure, electrodes 21 and 23
(Especially the electrode 21) is preferably formed of a metal vapor deposited layer or metal foil.

As described above, the pressure sensor of the present invention can be applied in many fields, and is effective for, for example, measuring the nip width between fixing rolls. In addition, the pressure sensor designed as shown in FIG. 5 can measure with an accuracy that is less than the width and spacing of the electrode pattern.

〔effect〕

The thus obtained pressure sensing element of the present invention provides the following first-order effects due to the arrangement of the electrode separation member.

(1) The distance and elasticity between the upper and lower electrode sheets can be changed.

(2) Damage to the pressure-sensitive conductive layer can be prevented.

(3) When used at high temperatures, even if the hardness of the pressure-sensitive conductive layer decreases, the total hardness (elasticity) of the sensor can be prevented from decreasing, so deformation is less likely to occur.

(4) Interference with adjacent electrode sheets or pressure-sensitive conductive layers can be suppressed, and highly accurate detection can be performed at suppressed positions.

(5) Better hysteresis characteristics can be obtained by combining various electrode sheets and electrode separation members made of materials with various shapes.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of three examples of pressure sensing elements according to the present invention. FIG. 2 is a cross-sectional view of three examples of electrode sheets. FIG. 3 is a perspective view of three examples of electrode separation members. FIG. 4 is a diagram showing three examples of electrode patterns and an example of the pattern of the electrode separation member. FIG. 5 is an example of a patterned electrode and an electrode separation member similar to those shown in FIG. 4. FIG. 6 is a sectional view of a pressure sensing element according to the present invention as a modification of the one shown in FIG. FIG. 7 is a diagram for explaining the outline of a conventional pressure detection element. la, lb, lc, ld, le - electrode sheet 11.12
, 13... Resin film 21, 22, 23... Electrode 31. 32, 33... Pressure sensitive conductive layer 4... Electrode separation layer member 0... Opening etc. 41... Protrusion) (2\) (A) Ryo 30 (B) (8) (D) (BO) (B) (8) (B) (,\) Ko I do

Claims (1)

[Claims] 1. A pressure sensing element comprising a pressure sensitive conductive layer sandwiched and laminated between two electrode sheets.