JPH08297061A - Tactile sensor - Google Patents

Abstract

PURPOSE: To obtain a tactile sensor for detecting a two-dimensional surface state, or the like, efficiently without being accompanied by the danger of electric spark or electric shock while suppressing an electromagnetic trouble. CONSTITUTION: The tactile sensor comprises a plurality of sensor units arranged integrally on a plane wherein each sensor comprises one or a plurality of single fiber single mode optical fibers 5 arranged so that a light can enter a flexible reflective film 1 or leave therefrom through the same air gap 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light detection type tactile sensor head which can be used for shape recognition by detecting contact pressure or pressure.

[0002]

2. Description of the Related Art Heretofore, there has been known a pressure sensor composed of a semiconductor pressure gauge in which a displacement due to the pressure is detected by an electric signal using a silicon diaphragm as a change in piezo resistance or capacitance.

However, the two-dimensional detection of the surface condition by the above-mentioned sensor has a problem that it is practically difficult because the movement along the surface is required. Also, it is susceptible to electromagnetic interference and cannot be accurately detected due to the noise in the atmosphere where high-frequency equipment is present, or the problem that it cannot be applied to explosive atmosphere or living body due to the risk of electric spark or electric shock. There was also.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to obtain a tactile sensor head capable of efficiently detecting a two-dimensional surface state and the like without being easily affected by electromagnetic interference and without risk of electric spark or electric shock. To do.

[0005]

According to the present invention, a plurality of optical fibers made of single fibers or one single mode optical fiber made of single fibers are incident on a flexible reflection film through the same void portion. Another object of the present invention is to provide a tactile sensor head characterized in that a plurality of sensor units arranged in a state where light can be emitted are integrally arranged in a plane.

[0006]

With the above structure, the flexible reflecting films integrally arranged in a plane are displaced according to the surface condition and pressure of the contact portion, and the displacement of each flexible reflecting film is optically By detecting via a fiber, the surface state and the like can be detected two-dimensionally at the same time as the total of the contact points of the flexible reflective films.

In the above, in the sensor unit provided with a plurality of optical fibers, light is emitted (emits) from a part of the optical fibers and reflected by the flexible reflection film, and the reflected light is left by the remaining optical fibers. Receive (light) measure the amount of light,
The surface state and the like are detected from the correspondence relationship between the degree of displacement of the flexible reflective film and the amount of reflected light depending on the contact location.

On the other hand, in the sensor unit provided with one single mode optical fiber, the single mode light is emitted from the optical fiber and reflected by the flexible reflection film,
The reflected light is received by the same optical fiber and its phase is examined,
The surface state or the like is detected from the correspondence relationship between the change of the optical distance due to the displacement of the flexible reflective film according to the contact location and the phase of the reflected light.

[0009]

EXAMPLE A tactile sensor head according to the present invention is configured such that a plurality of optical fibers made of single fibers or one single mode optical fiber made of single fibers are incident on a flexible reflection film via the same void portion. / And a plurality of sensor units arranged in a state where light can be emitted are integrally arranged in a plane.

FIG. 1 illustrates a tactile sensor head according to the present invention. Reference numeral 1 is a flexible reflective film, 21 is a void portion, and 5 is an optical fiber made of single fiber. The flexible reflective film 1 has a plurality of holes (21) formed in one frame spacer 2,
A plurality of sensor units having a flexible reflective film are provided on the same side of one side of the frame spacer,
They are arranged in a plane and integrally via one frame spacer.

Further, the optical fiber 5 made of a single fiber is arranged in such a state that light can be incident on and / or emitted from the flexible reflection film 1 in each hole of the frame spacer 2, whereby the sensor unit can be formed. Are formed. A plurality of optical fibers made of single fibers arranged through the same void portion made of the hole portion of the frame spacer in the sensor unit,
Alternatively, it is one of single mode optical fibers.

FIG. 2 exemplifies a sensor unit in which a plurality of optical fibers 6 made of single fibers are arranged. Also in FIG.
The sensor unit in which one single-mode optical fiber 7 made of a single fiber is arranged is illustrated. In these sensor units, the flexible reflective film 1 is provided on one side of the transparent substrate 3 via the hole of the frame spacer 2, and the void 21 formed of the hole is formed in a sealed state. Optical fiber 6,
7, the tip of which is disposed via the void portion 21 and the transparent substrate 3 and is adhesively fixed via the guide hole 41 of the support 4 to allow light to enter and / or light to exit.

In the present invention, the sensor unit may be arranged in such a state that a predetermined optical fiber can enter and / or emit light through the same gap with respect to the flexible reflective film, as shown in FIG. It is also possible to omit the transparent substrate 3 in FIG. 3 to have a structure in which the optical fiber is directly connected to the void portion, or the like, and it is possible to form an appropriate structure.

It should be noted that, in the above, the transparent substrate 3 is formed in order to efficiently form a sealed void portion for the purpose of forming the void portion as a depressurized or pressurized atmosphere with an appropriate gas such as argon, nitrogen or air. Used. That is, the pressure in the void can be controlled by sealing the void in a reduced pressure atmosphere or a pressurized atmosphere, and the bending characteristics of the flexible reflective film can be adjusted.

In the present invention, it may be formed as an unsealed space. Frame spacer 2 and support 4
It can be formed by connecting an optical fiber to the adhesive body, and has the advantage of being excellent in mass productivity, and is usually formed as a void portion at atmospheric pressure.

On the other hand, the reference numeral 11 shown in FIGS.
It is a protrusion. The protrusions are for making the flexible reflective film 1 easily bend when the sensor head is brought into contact with the detection target, and are provided on the outside of the flexible reflective film in a protruding state as necessary.

In the present invention, the flexible reflective film can be formed of an appropriate material that reflects the light used for measurement and is flexible enough to be deformed according to the surface condition of the contact object or the pressure. Generally, a metal thin film formed by a vapor deposition method or a plating method or a plastic film provided with the metal thin film, particularly a rubber plastic film, a metal foil, or a light-reflecting semiconductor thin film is used. The displacement amount at the time of contact can be adjusted by controlling the thickness of the flexible reflective film, and the sensor head can be formed according to the purpose of use.

The flexible reflection film and the optical fiber may be arranged in the sensor unit through the gap by an appropriate method. The formability of the gap and the regulation of the distance between the flexible reflection film and the optical fiber may be restricted. A method using a frame spacer is preferable from the viewpoint of the property.

The depth of the void portion, that is, the distance between the flexible reflection film and the transparent substrate or support, or the thickness of the frame spacer may be appropriately determined. Generally 10 mm or less, especially 0.0
It is about 1 to 3 mm.

The diameter of the void portion is 10 mm or less, preferably 5 mm or less, and particularly 1 mm or less from the viewpoint of downsizing of the sensor unit and eventually the sensor head. When connecting a plurality of optical fibers, it is preferable from the viewpoint of detection accuracy that the gap diameter is equal to or larger than the arrangement diameter of the optical fibers. Further, in the case of connecting one single mode optical fiber, it is preferable from the viewpoint of detection accuracy and the like that the gap diameter is larger than half the diameter of the optical fiber.

The use of the frame spacer has an advantage that a plurality of sensor units can be efficiently formed in a plane and integrally arranged as described above. The frame spacer is
Since it suffices to form a plurality of holes, it can be formed of an appropriate material. Generally, it is formed of a polymer, a metal, or a semiconductor.

The frame spacer made of polymer or metal can be obtained, for example, by subjecting a sheet, a plate, or the like to fine perforation treatment such as micron order by a laser light irradiation method or a fine electric discharge machining method.

The frame spacer made of a semiconductor such as silicon can be obtained by, for example, a micromachining method according to the formation of a semiconductor circuit in which patterning by photolithography and anisotropic etching are performed on a semiconductor substrate. In that case, a thin film to be a flexible reflection film is attached to one surface of the semiconductor substrate in advance by a vapor deposition method or the like, and after patterning, anisotropic etching is performed from the back surface of the semiconductor substrate to form a flexible reflection film integrated type. You can also get the diaphragm of.

FIG. 4 illustrates a method of manufacturing a diaphragm unit having a cross-sectional shape as illustrated in FIG. 2 by anisotropically etching a silicon substrate. That is, in FIG. 4, after a chromium film 24 and a gold film 25 are sequentially formed on one surface of a silicon substrate 23 (a) provided with silica layers 22 on both surfaces by thermal oxidation or wet oxidation by a vapor deposition method or the like (b), The chromium film and the gold film are patterned by the photolithography method to expose a part of the silica layer 22 (c).

Next, the silica layer 22 on the opposite surface is patterned by photolithography to partially expose the surface of the silicon substrate (d), and the exposed portion 26 is anisotropically etched by an etchant to be perforated. Then, the silica layer 22 on the back surface is exposed to form the holes 21 (e).

Next, the silica layer 22 exposed in the holes 21
To expose the chromium layer 24 (f). In that case, the chrome layer functions as an etching stop layer, and thereby the frame spacer 2 as a diaphragm is obtained which integrally has a desired flexible reflection film made of a chrome and gold superposed film.

As the transparent substrate used as necessary in the present invention, an appropriate substrate having transparency to the used light can be used. Generally, transparent ceramics such as glass and polymers are used. The thickness of the transparent substrate is arbitrary and is generally 10 mm or less, preferably about 0.1 to 5 mm. As the transparent substrate, a substrate having a lens function such as an array plate of microlenses can be used.

In the present invention, the support 4 shown in the drawings is used as needed, but the support is mounted and fixed with an optical fiber through a guide hole 41 provided in the support, such as a transparent substrate or a diaphragm. This is for maintaining a good connection state of the optical fiber to the frame spacer. Such a support can be formed according to the above-described frame spacer forming method such as a laser light irradiation method, a fine electric discharge machining method, or a micromachining method.

The protrusions provided on the outside of the flexible reflective film and provided as necessary include a method of forming the flexible reflective film in a multi-step form by a photolithography method or a laser ablation method on a polymer material. Alternatively, a fine projection array may be formed separately by a suitable method such as a method of adhering it to the flexible reflective film. The height of the protrusion can be appropriately determined according to the allowable bending amount of the flexible reflective film and the like. By the way, in the case of a flexible reflective film made of a gold film having a 130 μm square and a thickness of 1 μm, the allowable bending amount is about 6 μm.

In the above, the respective parts forming the tactile sensor head may be assembled by adhering them by an appropriate method using an adhesive or the like. The manufacturing method that excels in mass productivity is that each component other than the optical fiber is formed of a material such as glass or silicon capable of anodic bonding, and they are laminated in the form of a sheet or plate in which many sensor units are arrayed. After anodic bonding, have a predetermined number of sensor units before mounting the optical fiber in a row or column or row state, for example, in a row or column state of 4 × 4, 8 × 8, 16 × 16, etc. This is a method of cutting each tactile sensor head of a target size and attaching and fixing an optical fiber to it.

In the present invention, a single fiber is used as the optical fiber. As a result, an optical fiber with excellent thinness can be obtained, and a small or ultra-small sensor unit, and thus a tactile sensor head can be obtained. By the way, in the type of connecting a plurality of optical fibers, especially two optical fibers using an optical fiber with a diameter of 100 to 200 μm,
It is possible to obtain a sensor unit having an outer diameter of 0.4 to 1.2 mm. Further, in the type in which one single mode optical fiber is connected, the outer diameter is 0.2 to 0.
It is possible to obtain a tactile sensor head consisting of a 5 mm sensor unit.

Although a multi-mode optical fiber is generally used for forming a tactile sensor head composed of a sensor unit of a type in which a plurality of optical fibers are connected, a single-mode optical fiber may also be used. The optical fiber used may be made of an appropriate material such as plastic or glass. The optical fiber may be connected to a transparent substrate, a support or the like by an appropriate method such as an adhesive method.

The tactile sensor head of the present invention detects the surface shape and pressure in a two-dimensional manner by bringing it into contact with the object to be detected. The tactile sensor is formed by, for example, each light extending from the head. It can be formed by a method in which a fiber is connected to a light source or a detector via an optical system including an optical switch and an optical waveguide.

Incidentally, the above-mentioned optical switch includes, for example, an 8 × 8 or 16 × 16 optical multi-switch, and the optical waveguide includes a 128 × 128 optical waveguide. Further, as the light source, an LED or a semiconductor laser can be used. The LED is preferably used in the case of the intensity modulation method for measuring the intensity of the reflected light, and the semiconductor laser can be preferably used in the case of the phase modulation method for measuring the phase difference of the reflected light.

Further, as the detector, an appropriate detector can be used according to the intended detection accuracy. For example, in the case of the intensity modulation method described above, when a deflection of 2.5 μm or more is to be detected, it can be detected by a usual light amount measuring device, and 2 μm
When a minute deflection such as the following is to be detected, it can be detected by using a light source and a high-resolution light quantity measuring device that can accurately know the light emission quantity. In the case of the phase modulation method, although the size of the apparatus is increased, half the wavelength of the light used for measurement, that is, in the case of light having a wavelength of 0.85 μm, it is about 0.
Deflection of 4 μm can also be detected and highly accurate detection can be achieved.

Specific applications of such a tactile sensor include:
Attached to the hand of the robot hand, the presence or absence of contact between the hand and the work target or environment, and further detection of contact pressure and its distribution, detection of the food processing process and the hardness of food after processing and its distribution, or Examples include detection of hardness distribution in a living body lesion.

[0037]

According to the present invention, a surface state or the like can be efficiently detected on a two-dimensional scale, and the light can be applied to a living body without being affected by electromagnetic interference and without danger of electric spark or electric shock. A detection type tactile sensor head can be obtained.

[Brief description of drawings]

FIG. 1 is a partial sectional perspective view of an embodiment.

FIG. 2 is a sectional view of an example of a sensor unit.

FIG. 3 is a sectional view of another sensor unit example.

FIG. 4 is an explanatory view of an example of a diaphragm manufacturing process.

[Explanation of symbols]

 1: Flexible reflective film 2: Frame spacer 21: Void (hole) 3: Transparent substrate 4: Support 5, 6, 7: Optical fiber

Claims (4)

[Claims] 1. A plurality of sensor units formed by arranging a plurality of optical fibers made of single fibers in a state capable of entering or exiting light through a same void portion with respect to a flexible reflective film, are integrally formed in a planar shape. A tactile sensor head characterized by being arranged in a line. 2. A plurality of sensor units in which a single-mode optical fiber made of a single fiber is arranged in a state in which light can enter and exit from a flexible reflective film via a gap portion in a planar shape. A tactile sensor head characterized in that it is arranged in a regular pattern. 3. The tactile sensor head according to claim 1, wherein the flexible reflective film has a protrusion protruding to the outside. 4. The tactile sensor head according to claim 1, wherein the void portion is formed in a sealed state.