JPH01254827A - Pressure sensing plate for detecting uneven image pressure distribution - 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 Industrial Application) The present invention relates to a pressure sensitive plate for detecting pressure distribution on an uneven surface, which detects the distribution of an uneven surface by bringing minute uneven surfaces into contact with each other.

(Conventional Technique #4) Conventionally, to measure two-dimensional pressure distribution, a method has been known in which pressure transducers such as load cells and flexible surface pressure sensors are arranged in a matrix and the outputs of the pressure transducers are scanned. (For example, Japanese Patent Application Laid-Open No. 62-71828). In addition, by arranging a large number of electrode pairs facing each other in a matrix, and detecting the change in the capacitance formed by the electrode pairs as the spacing between the electrode pairs changes in the area where pressure is applied, pressure can be measured. Devices for measuring distribution are also known (for example, JP-A-62-226030).

However, in all of these measurements of blood pressure distribution, the resolution distance, that is, the interval between the minimum surface pressure distributions, is several mm or at most, and it is not possible to measure pressure distributions smaller than that. like 20
0-300. Since it is impossible to measure the pressure distribution on a surface with minute irregularities on the order of gm due to the interference of the pressure-sensitive member, conventional
A device that measures pressure distribution on surfaces with minute irregularities of about 00p or less was on display for a long time.

(Objective and Structure of the Invention 1&) The present invention has been made in view of the above points, and aims to measure the pressure distribution on a fine uneven surface of about 1100 JL or less by using contact pressure, and achieves this purpose. In order to do this, we propose a structure that separates the pressure-sensitive parts independently, which includes a pressure-receiving sheet having a plurality of protrusions arranged at minute intervals, and a sensing element separated at a position corresponding to at least the protrusions on the pressure-receiving sheet. In order to do this, a pressure sensitive sheet having holes and an electrode base having a pair of electrodes formed to be spaced apart and intersecting at positions corresponding to the holes of the pressure sensitive sheet are laminated,
The pressure-sensitive plate was constructed so that changes in the physical properties inside the holes of the pressure-sensitive sheet were measured from a pair of electrodes on the electrode base due to the force applied to the pressure-sensitive sheet when the uneven surface was brought into contact with the pressure-sensitive sheet.

This structure allows the surface pressure sensor to be separated, making it possible to measure pressure distribution on finely uneven surfaces.

(Example) The unoccurred IJI will be explained below based on the drawings.

1 to 4 show an embodiment of a pressure sensitive plate for detecting pressure distribution on an uneven surface according to the present invention.

Figure 1 shows the external appearance of the pressure-sensitive plate.The thickness of the pressure-sensitive plate 1 is about 1100mm, and the size depends on the purpose, but for example, if it is used for fingerprint detection, it is 150mmX, which is enough for one fingertip to rest on.
It is about 150mm.

FIG. 2 is an exploded perspective view of the pressure sensitive plate.

The pressure-sensitive plate 1 includes a pressure-receiving sheet la as shown in FIG.
It is constructed by pasting together a pressure-sensitive sheet lb as shown in (b) and an electrode base lc as shown in (c).

The pressure receiving sheet la is a sheet made of an elastic material such as silicone rubber or raw rubber with a thickness of about 50 gm using a mold, etc., and the surface has protrusions 11 in a matrix shape with a pitch of about 50 gm, a diameter of about 30 pm, and a height of about 30 gm. A large number of these were formed. The number of protrusions 11 may be determined depending on the application, but
For example, for fingerprint detection, the above-mentioned 150mm x 1
Approximately 300 x 300 pieces within 50 mm is good. Protrusion 11
It is preferable to form a protective film 11jJ11P with resin or the like on the surface of the pressure sensitive sheet 11P (see Figure 4).The pressure sensitive sheet lb is made of a resin film such as polyimide or polyester, or a ceramic or polymer film with a thickness of approximately 204 m to 50 JLm. Etching is performed on the insulating sheet 20 of
Holes 21 are formed in a matrix with the same pitch and number as the protrusions 11 of the pressure-receiving sheet la using a laser or a physical method (for example, drilling with a pin). hole 21
The diameter is approximately 30ILm. A pressure-sensitive conductive material 22 is embedded in each formula 21, and Toshiba Siltouch 100, 200, and 300 (trade name) are used as examples of this pressure-sensitive conductive material. The pressure-sensitive conductive material 22 may be a liquid or particles, and may be applied and embedded in the form of a paint.

The electrode base lc is etched in parallel in the vertical direction on one side (the back side in FIG. 2 (c)) of a relatively hard plate member 30 made of glass or ceramics at intervals equal to the pitch of the protrusions 11 of the pressure receiving sheet la by a method such as etching. A large number of X electrodes 31 are formed on the other surface (the front surface in FIG. 2(C)), and a large number of Y electrodes are formed in horizontal rows by etching or the like at intervals equal to the pitch of the protrusions 11 of the pressure receiving sheet 1a. From each Y electrode 32, a plate member 3 is formed.
As shown in FIG. 3, the electrode pieces 32a, 32a
', 32b, 32b', 32c.

32c', . . . are exposed on the surface of the plate member 30. The exposed position of these electrode pieces is the X formed on the surface.
Together with the electrode 31, it is in a position in contact with the pressure-sensitive conductive material 22 of the pressure-sensitive sheet lb. The X electrode 31 on the surface is the plate member 3
The Y electrode 32 on the back surface is focused on the other side 30b of the plate member 30. Connectors for connection to an external circuit are connected to these two sides 30a and 30b of the plate member 30, and the external circuit is connected to the X electrode 31 and the Y electrode 3.
2 are electrically connected.

As shown in FIG. 4, these pressure-receiving sheet la, pressure-sensitive sheet 1b, and electrode base Ic include a protrusion 11, a pressure-sensitive conductive material 22, an
. . . are joined in a corresponding positional relationship to form a pressure-sensitive plate l. The basic circuit configuration of a detection circuit is shown.

Detection circuits using this type of matrix scanning are already known and are not the gist of the present invention, so they will be briefly described.

100 is a reference signal generator, and a controller 101 divides the reference signal generated from the reference signal generator 100 and generates an X-direction scanning signal S to be applied to the X electrode and a Y-direction scanning signal SV to be applied to the Y electrode. Occur. 102 is an X-direction scanning control circuit that outputs an X-direction switching signal that turns on the X-direction analog switch 104 at a predetermined timing based on the scanning signal S from the controller 101; A Y-direction scanning control circuit that outputs a Y-direction switching signal that turns on the Y-direction analog switch 105 at a predetermined timing, ioe is X
An amplifier amplifies the signal obtained from the pressure sensitive plate 1 via the directional analog switch 104, 107 is a signal processing circuit including noise processing, and 108 compares the processed area distribution signal with a reference voltage vR obtained from the resistor R. A case where a surface distribution signal is generated will be explained.

When a fingertip is placed on the pressure sensitive plate l and pressed lightly, the protrusion 11 of the pressure sensitive sheet la is pressed by the pile of fingerprints. Assuming that the fingerprint ridge P is positioned with respect to the pressure receiving plate 1a as shown by the chain line in FIG. 4, the protrusions 11a, llb, llc, ll
d is strongly pressed down, and as a result, the pressure-sensitive conductive materials 22a, 22b, 22c,
22d is pressurized and becomes conductive. As a result, the X electrode 31a and Y electrode pieces 32a, 31b and 32 directly below
b, 31c, and 32c are electrically conductive, so that the comparator 10B of the detection circuit shown in FIG. A fingerprint pattern signal consisting of 0'' is output. In this way, fingerprint pattern information can be detected.

In all of the above embodiments, the protrusions of the pressure-receiving sheet la, the pressure-sensitive conductive material portions of the pressure-sensitive sheet ib, and the intersections of the X and Y electrodes of the electrode base lc are all aligned in a matrix. However, although the intersections of the pressure-receiving sheet la and the electrode base 1c are arranged in a matrix, the portions of the pressure-sensitive conductive material of the pressure-sensitive sheet lb are smaller than the pitch of the protrusions 11 of the pressure-receiving sheet la, which are spaced from each other. (For example 10~
20ILm)L, the diameter of each part is smaller than the diameter of protrusion 11'
As long as they are small (for example, 15 to 20 gm), they may be arranged randomly instead of in a matrix.

FIG. 6 shows, in cross section, another embodiment of the pressure sensitive plate according to the invention.

This embodiment is a pressure-sensitive plate using magnetic action, and the pressure-sensitive plate l is a pressure-sensitive sheet l having the same structure as shown in FIG. 2(a).
a, a pressure-sensitive sheet lb that senses unevenness using magnetic action, and an electrode base 1c having the same structure as that shown in FIG. 2(c).

A description of the pressure-sensitive sheet 1a and the electrode base 1c will be omitted, and only the pressure-sensitive sheet 1b will be described.

The pressure-sensitive sheet lb is a non-magnetic sheet 40 made of resin film or ceramics, in which holes 41 are formed in a matrix with the same pitch and number as the protrusions 11 of the pressure-sensitive sheet la by etching, laser, physical means, etc. be. The diameter of the hole 41 is approximately 30 JLm. Magnetizable fine particles 42 such as iron powder are placed in the six holes 41. This particle 42 is then magnetized. This particle 42 may be one particle, or may be a plurality of particles, or may be already magnetized, such as a magnet.

An elastic film 43 made of silicone rubber or the like is arranged under the non-magnetic sheet 40, and a ferromagnetic magnetoresistive confectionery 44 is arranged at a position corresponding to the hole 41 in the elastic film 43.

The electrode base lc is connected to the magnetoresistive element 44 through its electrode pair of the X electrode 31 and the Y electrode piece 32a.

The pressure sensitive plate l of this embodiment has a ferromagnetic material a-resistance effect, that is, when a 'FL current is applied to the magnetoresistive element 44 via the X electrode 31 and the Y electrode 32, a magnetic field is applied to the resistance element 44. The effect that the resistance value of the resistance element 44 changes depending on the direction and magnitude of the magnetic field is the same as that shown in FIG.

For example, to detect a fingerprint pattern, place your fingertip on the pressure sensitive plate l and press it lightly to detect the fingerprint pattern on the controller 101.
lt! , when a voltage is applied and scanned at the timing of pole 31 and Y 'lfl pole 32 at pole position 2, the particles 42 of the pressure-sensitive sheet lb below are moved downward by the protrusion 11 of the pressure-receiving sheet la pressed by the fingerprint mountain. , the magnetoresistive element 44
The magnetic field applied to becomes larger. As a result, the X electrode 31 and the Y
7+! rr between pole 32! , it is possible to detect the ridges, or irregularities, of a flowing fingerprint.

As a modification of this embodiment, as shown in FIG.
1, put iron powder particles 42 in it, stick a magnetized piece 45 on the lower surface of the pressure-receiving sheet la placed thereon at a position corresponding to the protrusion 11, and place a magnetoresistive element on the electrode pair of the electrode base lc. However, when the protrusion 11 is pressed, the magnetized state of the magnetized piece 45 reaches the magnetoresistive element 44 via the iron powder particles 42, so a sensitizing effect is obtained and the unevenness can be detected reliably. .

Instead of the elastic membrane 43 in the embodiment shown in FIG. 6, elastic pieces may be inserted into the bottoms of the six holes 41 of the non-magnetic sheet 40.

FIG. 8 shows, in cross section, still another embodiment of a pressure sensitive plate due to unoccurred IJI.

This example is a pressure sensitive plate that utilizes changes in capacitance.
The pressure-sensitive plate l is made by pasting together a pressure-receiving sheet la having the same structure as shown in FIG. configured.

For the pressure-sensitive sheet tb, holes 51 are formed at the same pitch and number as the projections 11 of the pressure-receiving sheet 1a by etching or a physical method in the metal thin film 11q50, and elastic layers 52 and 53 are arranged above and below this metal thin film 50. Electrodes 54 and 55 made of metal material are provided at positions corresponding to the holes 51 in the elastic membranes 52 and 53.
are formed, and shield films 56 and 57 made of metal foil are disposed further outside the lithium films 52 and 53.

The electrodes 54 formed on the upper elastic membrane 52 constitute parallel Y electrodes, and the electrodes 55 formed on the lower elastic membrane 53 constitute parallel X electrodes. X
A detection circuit for forming the electrode 53 and the Y electrode 54 is not particularly shown, but similarly to the pressure-sensitive plate using the pressure-sensitive conductive material described above, the Y electrode 54 is sequentially switched to apply a high frequency signal, and the X electrode 55 are sequentially switched and scanned, and when the protrusion 11 of the pressure receiving plate 1a is pressed by the mountain-like convex part of the fingerprint, the electrode 54 on the upper elastic membrane 52 and the electrode 55 on the lower elastic membrane 53 are connected. As the interval becomes smaller, the capacitance between the two electrodes changes and the electric field intensity input from the Y electrode becomes larger, so that irregularities can be detected.

In this case, since each intersection of the matrix is shielded by the metal thin film 50 and the shields 56 and 57 under -L,
It can prevent radio wave radiation and interference, and can detect accurate patterns without being influenced by others.

Various embodiments of the pressure sensitive plate according to the present invention have been described above.
In both cases, the multiple protrusions on the pressure-receiving sheet are separated and independent one by one, so when a convex part of the unevenness comes into contact with the surface of the pressure-receiving sheet, only the convex part or the contacting protrusion is pushed, and the adjacent protrusions are affected. is all<1! Since the pattern is cut off, the pattern of the protrusions can be detected accurately.

In the above embodiment, the unevenness is detected in a matrix, but the arrangement of the protrusions on the pressure receiving sheet and the electrodes may not be arranged in a matrix, but may be a combination of concentric and radial patterns, for example.

(Effects of the Invention) As explained above, in the present invention, there is provided a pressure-receiving sheet having a plurality of protrusions arranged at minute intervals, and a pressure-sensitive sheet having holes at least at positions corresponding to the protrusions of the pressure-receiving sheet. and an electrode base having a pair of electrodes formed to be spaced apart and intersecting at positions corresponding to the holes of the pressure-sensitive sheet, and when the uneven surface is brought into contact with the pressure-receiving sheet, the pressure-receiving sheet The structure is configured such that the physical properties inside the holes in the pressure-sensitive sheet change depending on the applied force, thereby changing the value of the current flowing through the pair of electrodes of the electrode base. It is possible to accurately detect the pressure distribution on an uneven surface, and is suitable for detecting the pressure distribution on a fine uneven surface such as a fingerprint pattern.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an embodiment of a pressure-sensitive plate for detecting pressure distribution on an uneven surface according to the present invention, and FIG. 2 is an exploded perspective view of the pressure-sensitive plate shown in FIG. B) is a pressure sensitive sheet, and (C) is an electrode base. Figure 3 is Figure 2 (c)
4 is a partially enlarged perspective view of the electrode base shown in FIG. 4, a partial sectional view of the pressure sensitive plate shown in FIG. 1, and FIG. The basic circuit configuration of the detection circuit, FIG. 6 is a partial sectional view of another embodiment of the pressure sensitive plate for detecting pressure distribution on an uneven surface according to the present invention, and FIG. 7 is a modification of the pressure sensitive sheet of the pressure sensitive plate shown in FIG. 6. Cross-sectional view showing an example, No. 8
The figure is a partial sectional view of still another embodiment of the pressure sensitive plate for detecting pressure distribution on an uneven surface according to the present invention. l...pressure sensitive plate, 1a...pressure receiving sheet, tb...pressure sensitive sheet, lc...electrode base, ll...protrusion, 2
0--Insulating sheet, 21--Hole, 22--Pressure-sensitive conductive material, 30--Plate member, 31-X electrode, 32-Y
Electrode patent applicant Enix Co., Ltd. Agent Patent attorney Hiroshi Suzuki Younger brother 1 Figure 3 Figure 4 Figure 2 (A) Figure 6 Figure 7 Figure 8

Claims (4)

[Claims] (1) A pressure-receiving sheet having a plurality of protrusions arranged at minute intervals, a pressure-sensitive sheet having holes at least at positions corresponding to the protrusions of the pressure-receiving sheet, and positions of the pressure-sensitive sheet corresponding to the holes. and an electrode base having a pair of electrodes formed so as to be spaced apart from each other so as to intersect with each other. 1. A pressure-sensitive plate for detecting pressure distribution on an uneven surface, characterized in that the internal physical properties are changed so that the current or voltage detected through the set of electrodes of the electrode base changes accordingly. (2) The pressure-sensitive sheet has a pressure-sensitive conductive material in the hole, and the set of electrodes of the electrode base are electrically connected to each hole via the pressure-sensitive conductive material. Pressure-sensitive plate for detecting pressure distribution on uneven surfaces. (3) The uneven surface according to claim 1, wherein the pressure-sensitive sheet has magnetic particles in the holes, and a set of electrodes of the electrode base are electrically connected to each hole via the magnetoresistive element. Pressure sensitive plate for pressure distribution detection. (4) Pressure distribution on an uneven surface according to claim 1, wherein a pair of electrode pieces face each other across a hole in the pressure-sensitive sheet, and are arranged such that the distance between the two electrode pieces changes depending on the force applied to the pressure-sensitive sheet. Pressure sensitive plate for detection.