JPH10227630A - Three-dimensional shape recognition sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a three-dimensional shape recognition sensor that can recognize a three-dimensional shape directly and accurately. SOLUTION: A sensor 1 has a sensor chip 4 with a plurality of pressure- sensitive sensor parts 5. The sensor chip 4 is joined to a chip junction surface S2 in a body 2. A plurality of pressure transfer holes 21 are formed in the body 2 so that they correspond to the pressure-sensitive sensor parts 5. A pressure transfer medium 22 is filled into each pressure transfer hole 21. An opening with each pressure transfer hole 21 is formed on a shape recognition surface of the body 2. A pressure reception body 31 for transferring a pressure to the pressure transfer medium 22 is arranged at the opening.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sensor for recognizing a three-dimensional shape.

[0002]

2. Description of the Related Art Conventionally, when it is desired to recognize minute irregularities (for example, a fingerprint or Braille) on the surface of an object, the following method has been employed, for example.

First, a plurality of one-dimensional shapes of an object to be inspected are recognized using some kind of sensor. These sensing data are input to a computer as a detection signal, where they are collected and processed into one three-dimensional shape data. As a result, the three-dimensional shape is indirectly recognized.

[0004]

However, in an indirect three-dimensional shape recognition method as in the prior art, there is a limit in improving the recognition accuracy, and therefore, a sensor capable of directly recognizing a three-dimensional shape is available. Was desired. Further, in the prior art, since it is necessary to obtain three-dimensional shape data from one-dimensional shape data, there is a problem that a complicated arithmetic processing program is required. Therefore, from the viewpoint of simplifying the system, a sensor that does not require such a complicated program has been desired.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a three-dimensional shape recognition sensor capable of directly and highly accurately recognizing a three-dimensional shape.

[0006]

In order to solve the above-mentioned problems, according to the first aspect of the present invention, a sensor chip having a plurality of pressure-sensitive sensors is provided on a chip bonding surface of a body, and each of the pressure-sensitive sensors is provided. A plurality of pressure transmission holes are formed in the body so as to correspond to the sensor unit, and a pressure transmission medium is filled in each of the pressure transmission holes, and the pressure transmission holes of the pressure transmission holes on the shape recognition surface of the body are formed. The gist of the present invention is a three-dimensional shape recognition sensor in which a pressure receiving body that transmits pressure to the pressure transmission medium is disposed in the opening.

According to a second aspect of the present invention, in the first aspect, the pressure receiving body comprises a plurality of pressure receiving pins movably inserted into the opening and a connecting thin plate interconnecting the pressure receiving pins. It became.

According to a third aspect of the present invention, in the second aspect, both the pressure-sensitive sensor portion and the pressure-receiving pin are arranged in an array, and each of the pressure transmitting holes is configured to recognize the shape from the chip joining surface. It spreads radially toward the surface.

Hereinafter, the "action" of the present invention will be described. According to the first aspect of the present invention, for example, when an inspection object having an uneven portion is arranged on the shape recognition surface, the pressure receiving body located at the position corresponding to the convex portion is immersed in the opening side of the pressure transmission hole. Is pressed. At this time, the pressure received by the pressure receiving body is transmitted to the chip joining surface side via the pressure transmitting medium in the pressure transmitting hole. The pressure is converted into an electric signal by a pressure-sensitive sensor unit on the sensor chip in accordance with the magnitude of the variation, and it is recognized whether or not a convex portion is present at a predetermined position of the inspection object. Therefore, with this configuration, the three-dimensional shape can be recognized directly and with high accuracy.

According to the second aspect of the present invention, since the pressure-sensitive pins are connected to each other by the connecting plate, the sensor can be relatively easily assembled even when the pressure receiving body is downsized.

According to the third aspect of the present invention, the area of the shape recognition surface is not restricted by the area of the sensor chip, so that a small sensor chip can be used.
Cost reduction can be achieved.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a three-dimensional shape recognition sensor 1 according to an embodiment of the present invention will be described in detail with reference to FIGS.

As shown in FIGS. 1, 3 and the like, the body 2 constituting the three-dimensional shape recognizing sensor 1 has a rectangular shape, the upper side of which is a shape recognizing surface S1 and the lower side thereof is a chip bonding surface S2. Assigned to. The shape recognizing surface S1 of the body 2 is substantially square, and in this embodiment, it is 10 mm.
It is formed in a size of about square to 20 mm square. In the present embodiment, hard glass is selected as the material of the body 2. The reason for selecting the hard glass is that it is convenient when anodic bonding the sensor chip 4 described later.

At the center of the sensor bonding surface S2, a rectangular bonding recess 3 is formed. A sensor chip 4 is provided in the joint recess 3. In the present embodiment, the sensor chip 4 is bonded to the bonding recess 3 by anodic bonding. As shown in FIG. 2, the sensor chip 4 includes a plurality of pressure-sensitive sensor units 5. The pressure-sensitive sensor units 5 are arranged in an array on one side surface of the sensor chip 4. In the present embodiment, the size of the pressure-sensitive sensor unit 5 is 0.1 mm square to 0.5 mm square, and the pitch thereof is 0.1 mm to 0.5 mm.

As shown in FIG. 5, the pressure-sensitive sensor section 5 has a diaphragm structure. The manufacturing method will be exemplified below. First, a silicon single crystal substrate 11 is prepared, and a polysilicon layer 12 is laminated on one side thereof. Next, after forming a silicon oxide film 13 on the polysilicon layer 12,
Impurities are implanted and diffused by a conventionally known method, and an opening serving as a contact hole 16 is formed at a position corresponding to the strain gauge 14. It should be noted that a plurality of strain gauges 14 are provided for one pressure-sensitive sensor unit 5, and they form one bridge circuit. Aluminum interconnection layer 15 is formed on silicon oxide film 13. Aluminum wiring layer 15 and strain gauge 14 are electrically connected via contact hole 16. The aluminum wiring layer 15 is connected to an external connection terminal (not shown) in a peripheral area in the same plane. The signal lines 18 are joined to the external connection terminals by soldering or the like. The detection signal of the pressure-sensitive sensor unit 5 is output to the outside via the signal line 18.

A cavity 17 is formed below the formation of the strain gauge 14 on the upper surface of the silicon single crystal substrate 11. Such a cavity 17 can be formed by a conventionally known technique such as crystal anisotropic etching and isotropic etching. As a result, the upper part of the cavity 17 becomes a diaphragm, so to speak, and the cavity 17 functions as a pressure reference chamber.

As shown in FIG. 3, a pressure transmitting hole 21 is formed in the body 2. The number of the pressure transmitting holes 21 is the same as that of the pressure-sensitive sensor unit 5. The secondary-side opening of the pressure transmitting hole 21 is formed in the bottom surface of the joint recess 3 in a state of being arranged in an array. Each secondary-side opening corresponds to the position of each pressure-sensitive sensor unit 5. Pressure transmission hole 21
Are formed in an array on the shape recognition surface S1 in an array. A pin receiving recess 23 having a diameter larger than that of the pressure transmission hole 21 is formed in the primary opening. The pitch of the primary opening is 0.2 mm to 0.6
mm. That is, the pressure transmitting holes 21 are radially spread from the chip bonding surface S2 to the shape recognition surface S1. The pressure transmitting hole 21 can be formed by a conventionally known method such as isotropic etching.

The pressure transmitting hole 21 is filled with a pressure transmitting medium 22. In this embodiment, a silicone gel is used. In addition, for example, a gel material made of a resin other than the silicone resin, silicone oil, or the like may be used.

As shown in FIGS. 1 and 3, on the shape recognition surface S1 of the body 2, a pin array plate 31 as a pressure receiving member is arranged. This pin array plate 31
Comprises a plurality of pressure receiving pins 32 and a connecting plate 33. The pressure receiving pins 32 are connected to each other and in an array by a connecting plate 33. The pitch of the pressure receiving pins 32 is equal to that of the primary side opening. Each of the pressure receiving pins 32 has a substantially cylindrical shape, and a tip portion thereof has a round shape. Pressure receiving pin 3
The two tip portions 32 a are present on the surface side of the connection plate 33.
The base end 32 b of the pressure receiving pin 32 is located on the back side of the connecting plate 33.

The back side of the connecting plate 33 is joined to the shape recognition surface S 1 of the body 2. At this time, the interface between the two 2 and 33 is sealed with a silicone adhesive 34 or the like in order to prevent the escape of pressure. At this time, the base end 32b of each pressure receiving pin 32 is housed in the corresponding pin housing recess 23. Note that the depth of the pin housing recess 23 is larger than the length of the base end portion 32 b of the pressure receiving pin 32. Also,
Since the connecting plate 33 is sufficiently thin, the pin array plate 31 has flexibility as a whole. Therefore, each pressure receiving pin 32 is movable along the depth direction of the pin housing recess 23.

The pin array plate 31 is, for example, L
IGA (Lithographie galvanoformung und Abformung
) Can be manufactured by micromachining techniques such as processes. In the LIGA process,
A photosensitive film having a thickness of several hundred μm is used. A desired pattern is transferred to the photosensitive film by X-rays having good parallelism. The deep holes obtained by the pattern transfer are plated with metal, whereby the pressure receiving pins 32 and the like are formed. This method is preferable because it is suitable for manufacturing a microstructure having a high aspect ratio. In this embodiment, the pressure receiving pin 32 having a diameter of about 0.1 mm to 0.3 mm is formed by such a method. However, the pin array plate 31 may be made of metal or resin.

Next, the operation of the thus constituted three-dimensional shape recognition sensor 1 will be described with reference to FIG. FIG. 4 shows a state in which an inspection object T1 having an uneven portion (for example, a finger having a fingerprint or a Braille book having Braille) T1 is pressed against the shape recognition surface S1 of the sensor 1. In this case, the pressure receiving pin 32 located at a position corresponding to the convex portion of the inspection object T1 is pressed by the convex portion in a direction of immersing in the pin receiving recess 23. Note that the larger the convex portion, the greater the pressing force received by the distal end portion 32a of the pressure receiving pin 32, and the greater the movement amount of the pressure receiving pin 32. At this time, the pressure receiving pin 32
Is transmitted to the pressure transmitting medium 22 by the end face of the proximal end portion 32b of the pressure receiving pin 32. Pressure transmission medium 2
Since 2 is filled in the entire pressure transmitting hole 21, the pressure is transmitted to the sensor chip 4 on the chip joining surface S2 side. Therefore, the increased pressure causes strain on the strain gauge 14 of the pressure-sensitive sensor unit 5. Then, the pressure-sensitive sensor unit 5 converts the result into an electric signal and outputs the electric signal to the outside via the signal line 18. In this case, a larger electric signal is output as the pressure fluctuation amount is larger.

On the other hand, no pressing force is applied to the pressure receiving pins 32 that are not located at positions corresponding to the convex portions of the inspection object T1, so that the pressure receiving pins 32 do not move. Therefore, the strain gauge 14 of the pressure-sensitive sensor unit 5 is not distorted, and no electric signal is output.

By integrating the above results, it is possible to recognize whether or not there is a projection at a predetermined position of the inspection object T1. Now, the characteristic effects of the present embodiment will be listed below.

(A) According to the three-dimensional shape recognition sensor 1, the three-dimensional shape can be directly recognized by pressing the test object T1 against the pin array plate 31 as described above. Therefore, unlike a conventional indirect three-dimensional shape recognition method in which a plurality of pieces of data relating to a one-dimensional shape are collected and subjected to arithmetic processing, the recognition accuracy is reliably increased. Therefore, if the sensor 1 is used, a high-performance fingerprint discrimination device, a Braille recognition device, or the like can be realized. Note that the sensor 1 of the present embodiment can of course be used for recognizing a two-dimensional shape.

Further, according to the sensor 1, since a complicated arithmetic processing program is not required, the system can be simplified. Further, the structure of the sensor 1 is not so complicated, so that it is relatively easy to manufacture and low-cost.

(B) In the three-dimensional shape recognition sensor 1,
The sensor chip 4 manufactured by a semiconductor process is used. For this reason, a large number of pressure-sensitive sensor units 5 are provided in a narrow area, which is excellent in that point. Further, the pressure-sensitive sensor unit 5 obtained as described above has excellent pressure-sensitive accuracy. Therefore, it is advantageous for miniaturization and high precision of the device.

(C) In the three-dimensional shape recognition sensor 1,
The pressure receiving pins 32 are connected to each other by a connecting plate 33. Therefore, the pressure receiving pins 32 do not fall apart individually. Therefore, even when the pin array plate 31 is miniaturized, the base end portion 32b of each pressure receiving pin 32 can be reliably accommodated in the corresponding pin accommodation recess 23. Therefore, the sensor 1 can be relatively easily assembled.

(D) In the three-dimensional shape recognition sensor 1,
The pressure-sensitive sensor section 5 and the pressure receiving pins 32 are both arranged in an array, and each pressure transmission hole 21 radially spreads from the chip bonding surface S2 to the shape recognition surface S1. With this configuration, the area of the shape recognition surface S1 is not restricted by the area of the sensor chip 4. Therefore, a small sensor chip 4 can be used, and cost reduction can be achieved.

The present invention is not limited to the above-described embodiment, but can be modified to, for example, the following forms. As in another example shown in FIG. 6, for example, a piezoelectric element 42 or the like may be formed on the diaphragm structure of the pressure-sensitive sensor unit 5 instead of the strain gauge 14. In this case, the piezoelectric element 42 is preferably formed by a semiconductor process.

In another example of the three-dimensional shape recognition sensor 51 shown in FIG. 7, a shape recognition surface S
1 is formed to be concavely curved. That is, the shape recognizing surface S1 may be flat or curved, and the object T1 may be inspected.
Any shape may be used as long as it conforms to the shape of.

The pressure receiving pins 32 may be individually separated and independent. Further, instead of the pin shape, for example, a spherical shape or the like may be adopted. ◎ The pin array plate 31, which is the pressure receiver, is
It may be produced by a method other than the process.

The pressure transmitting holes 21 do not necessarily have to spread radially, but may extend, for example, in parallel. The shape recognition surface S1 may be present on a plurality of surfaces of the bodies 2 and 52.

The detection signal processing circuit may be provided on the sensor chip 4. In this case, the detection signal processing circuit is formed on the surface on which the pressure-sensitive sensor unit 5 is formed or on the back surface thereof. In the latter configuration, it is not necessary to separately secure an area for forming the detection signal processing circuit beside the pressure-sensitive sensor unit 5, which is convenient for downsizing the sensor chip 4.

Here, in addition to the technical ideas described in the claims, the technical ideas grasped by the above-described embodiments are listed below together with their effects. (1) The three-dimensional shape recognition sensor according to any one of claims 1 to 3, wherein the pressure-sensitive sensor unit has a diaphragm structure, and a strain gauge is formed at a position where the diaphragm structure is present. With this configuration, recognition accuracy can be improved.

(2) The three-dimensional shape recognizing sensor according to the technical idea 1, wherein the plurality of strain gauges form a bridge circuit. With this configuration, the recognition accuracy can be further improved.

(3) The three-dimensional shape recognition sensor according to any one of claims 1 to 3, wherein the pressure-sensitive sensor section has a diaphragm structure, and a piezoelectric element is formed at a position where the diaphragm structure is located. . With this configuration, recognition accuracy can be improved.

(4) Claims 1 to 3 and technical ideas 1 to 3
3. The three-dimensional shape recognition sensor according to claim 1, wherein the pressure transmission medium is a gel. (5) The three-dimensional shape recognition sensor according to any one of claims 1 to 3, wherein the sensor chip includes a detection signal processing circuit. With this configuration, it is not necessary to provide such a circuit outside the chip.

(6) The three-dimensional shape recognizing sensor according to the technical concept 5, wherein the detection signal processing circuit is formed on the back surface side of the pressure-sensitive sensor portion forming surface. With this configuration, it is convenient to reduce the size of the sensor chip.

(7) Claims 1 to 3 and technical ideas 1 to 6
A fingerprint discriminating device comprising the three-dimensional shape recognition sensor according to any one of the above. With this configuration, it is possible to realize a fingerprint discriminating apparatus having excellent fingerprint discrimination accuracy.

(8) Claims 1 to 3 and technical ideas 1 to 6
A Braille recognition device comprising the three-dimensional shape recognition sensor according to any one of the above. With this configuration, it is possible to realize a Braille recognizing device that is excellent in Braille recognition accuracy.

The technical terms used in this specification are defined as follows. "Pressure transmission medium: In addition to a gel-like substance such as silicone gel, it also includes a liquid such as silicone oil."

[0043]

As described in detail above, according to the first to third aspects of the present invention, there is provided a three-dimensional shape recognition sensor capable of directly and highly accurately recognizing a three-dimensional shape. Can be.

According to the second aspect of the present invention, the sensor can be relatively easily assembled. According to the third aspect of the present invention, a small sensor chip can be used, and cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing an entire three-dimensional shape recognition sensor according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a sensor chip used in the sensor.

FIG. 3 is a schematic sectional view of the sensor.

FIG. 4 is a schematic sectional view of the sensor.

FIG. 5 is a partial schematic cross-sectional view of a pressure-sensitive sensor unit of the sensor chip according to the embodiment.

FIG. 6 is a partial schematic cross-sectional view of a pressure-sensitive sensor section of another example of a sensor chip.

FIG. 7 is a schematic sectional view of another example of a three-dimensional shape recognition sensor.

[Explanation of symbols]

1, 51 ... three-dimensional shape recognition sensor, 2, 52 ... body,
4, 41: sensor chip, 5: pressure-sensitive sensor section, 21: pressure transmitting hole, 22: pressure transmitting medium, 31: pin array plate as pressure receiving body, 32: pressure receiving pin constituting pressure receiving body, 33: pressure receiving body , A connecting plate, S1 ... shape recognition surface, S2 ... chip joining surface.

Claims (3)

[Claims] 1. A sensor chip having a plurality of pressure-sensitive sensors is provided on a chip bonding surface of a body, and a plurality of pressure transmitting holes are formed in the body so as to correspond to the respective pressure-sensitive sensors. Each pressure transmission hole is filled with a pressure transmission medium, and a pressure receiving body that transmits pressure to the pressure transmission medium is disposed at an opening of each pressure transmission hole on the shape recognition surface of the body. Features a three-dimensional shape recognition sensor. 2. The pressure receiving body according to claim 1, wherein the pressure receiving body comprises a plurality of pressure receiving pins movably inserted into the opening and a connecting plate connecting the pressure receiving pins to each other. 3D shape recognition sensor. 3. The pressure-sensitive sensor section and the pressure-receiving pins are both arranged in an array, and each of the pressure transmission holes radially extends from the chip bonding surface to the shape recognition surface. The three-dimensional shape recognition sensor according to claim 2, wherein