Contact area

Abstract

Regarding a tactile sensor that captures images from a side of an object different from the side it makes contact with, the present invention provides a contact portion that can clearly image the shape of the object. [Solution] The contact portion 6 is used in the tactile sensor 1 and comes into contact with the object. The contact portion 6 is equipped with a translucent elastic body 3A. One side of the elastic body 3A is covered with a reflective film 3C, and the other side is not covered with the reflective film 3C. The reflective film 3C contains particles 8, which are made by covering a flaky base material 8A with a film material 8B having a different refractive index from the base material 8A. The contact portion 6 is used to image the reflective film 3C through the elastic body 3A from the other side of the elastic body 3A.

Description

Technical Field

[0001] The present disclosure relates to a contact portion.

Background Art

[0002] Patent Document 1 discloses an optical tactile sensor that senses an object. This optical tactile sensor includes a contact portion that deforms upon contact with an object. The contact portion comprises a light-transmissive member and a filter portion. The light-transmissive member is a hemispherical member made of a gel material with transparency. The filter portion includes a first layer made of a white paint and a second layer made of a black paint. A marker portion with a mark printed thereon is provided on the filter-side surface of the light-transmissive member. The optical tactile sensor receives reflected light from the marker portion and generates an image of the marker portion when the contact state is established.

Prior Art Literature

Patent Literature

[0003]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0004] In the configuration of the contact portion of the optical tactile sensor disclosed in Patent Document 1, it was difficult to recognize finer deformation of the contact portion than the printing of the marker portion. Therefore, the sharpness of the shape of the object in the captured image has not been sufficient.

[0005] The present disclosure has been made in view of the above circumstances, and an object thereof is to provide a contact portion capable of clearly capturing an image of the shape of an object, with respect to a tactile sensor that captures images from the other surface side different from the one surface side with which the object comes into contact.

Means for Solving the Problem

[0006] The contact portion of the present disclosure is A contact part used in a tactile sensor that comes into contact with an object, Equipped with a translucent elastic material, The elastic body has one surface covered with a reflective film and the other surface not covered with the reflective film. The reflective film contains particles in which a scale-like substrate is covered with a film material having a different refractive index from the substrate. It is used to image the reflective film through the elastic body from the other side. [Effects of the Invention]

[0007] The contact portion relating to this disclosure is a tactile sensor that captures images from a side of the object that is different from the side that the object is in contact with, and is capable of clearly capturing the shape of the object. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is an explanatory diagram illustrating a tactile sensor according to the first embodiment. [Figure 2] Figure 2 is a schematic diagram illustrating the shape measurement system equipped with the tactile sensor shown in Figure 1. [Figure 3] Figure 3 is a schematic cross-sectional view illustrating the configuration of the tactile sensor near the touchpad shown in Figure 1. [Figure 4] Figure 4 is a conceptual diagram illustrating the configuration of the tactile sensor near the touchpad shown in Figure 1, as viewed from the imaging unit side. [Figure 5] Figure 5 is a schematic cross-sectional view of the particles contained in the reflective film of the tactile sensor shown in Figure 1. [Figure 6] Figure 6 shows an image of the object when a white reflective film was used as a comparative example. [Figure 7] Figure 7 shows an image of an object when a reflective film containing pearl pigment and binder was used as an example. [Modes for carrying out the invention]

[0009] Herein lies a preferred example of this disclosure.

[0010] [1] A contact portion used in a tactile sensor and configured to contact an object, comprising a translucent elastic body, wherein one surface of said elastic body is covered with a reflective film, and the other surface thereof is not covered with said reflective film, said reflective film comprises particles obtained by covering a scaly base material with a film material having a refractive index different from that of said base material, said contact portion being used for imaging said reflective film through said elastic body from said other surface side.

[0011] [2] The contact portion according to [1], wherein a ratio of specular reflectance to total reflectance of said reflective film is 0.1 or more and 0.2 or less in a wavelength range greater than 400 nm and less than 760 nm.

[0012] [3] The contact portion according to [1] or [2], comprising an external light suppressing film that covers an outer side of said reflective film and suppresses intrusion of light from said outer side.

[0013] [4] The contact portion according to [3], wherein said external light suppressing film has infrared transmittance.

[0014] [5] The contact portion according to any one of [1] to [4], wherein a particle diameter of said particles is 1 µm or more and 300 µm or less.

[0015] <First Embodiment> 1. Description of tactile sensor 1 The following description relates to a tactile sensor according to the first embodiment. FIG. 1 shows the tactile sensor 1 according to the first embodiment. The tactile sensor 1 is an optical sensor that senses an object W1. The tactile sensor 1 is applicable, for example, to a robot hand or a robot arm that contacts the object W1 or grips the object W1. Although an example of the object W1 is shown in FIG. 1, the shape and size of the object W1 are not limited to the example in FIG. 1, and objects of various forms can be targeted.

[0016] The tactile sensor 1 includes a case 2, a touch pad 3, an imaging unit 4, an irradiation unit 5, and the like. The tactile sensor 1 can constitute, for example, a shape measurement system 10 as shown in FIG. 2. The touch pad 3 is provided with a contact portion 6, a marker portion 20 (see FIG. 4), and the like.

[0017] In the present specification, a direction parallel to the optical axis X of the imaging unit 4 shown in FIG. 2 is an example of the imaging direction. In FIG. 2, the optical axis X of the imaging unit 4 is conceptually indicated by a one-dot chain line. In the present specification, the direction parallel to the optical axis X is also referred to as the vertical direction. In the present specification, in the above vertical direction, the side where the imaging unit 4 is provided is the upper side, and the side where the contact portion 6 is provided is the lower side.

[0018] The imaging unit 4 shown in FIG. 1 is an imaging device such as a CCD camera or a CMOS camera, for example. In a representative example, the imaging unit 4 can receive at least light in the visible light region to generate a captured image. For example, the imaging unit 4 can receive light in the visible light region and light outside the visible light region (for example, a first wavelength range) to generate a captured image. The imaging unit 4 is configured as a color camera in which an R element that generates red intensity information of incident light, a G element that generates green intensity information of incident light, and a B element that generates blue intensity information of incident light are arranged in a light receiving region. For example, RGB elements in which the R element, the G element, and the B element are combined in a predetermined arrangement are arranged in the light receiving region. It should be noted that the above-exemplified imaging device is merely an example, and any known camera may be used.

[0019] The imaging unit 4 is positioned on the opposite side of the contact area 6 from the side to which the object W1 makes contact. The imaging unit 4 photographs a predetermined range including the marker unit 20 from the opposite side to which the object W1 makes contact. Specifically, "the side to which the object W1 makes contact" refers to the space that the contact surface 6A faces among the two spaces separated by the contact area 6, and is the space where the object W1 exists. "The side opposite to the side to which the object W1 makes contact" refers to the space that the back surface 6B (see Figure 3) faces among the two spaces separated by the contact area 6, and is the space where the object W1 does not exist. In the example in Figure 1, "the side to which the object W1 makes contact" is the lower side of the contact area 6, and "the side opposite to the side to which the object W1 makes contact" is the upper side of the contact area 6. In other words, the imaging unit 4 photographs the marker unit 20, etc., from above the contact area 6. The imaging unit 4 can generate an image by receiving reflected light from the reflective film 3C (described later), reflected light from the marker unit 20, etc., and light in the first wavelength range from the outside (described later).

[0020] The illumination unit 5 shown in Figure 1 emits illumination light including visible light. The arrangement and size of the illumination unit 5 are such that the illumination light can be emitted onto the reflective film 3C. The illumination unit 5 may be, for example, a coaxial incident illumination or another type of illumination device. In a typical example, the illumination unit 5 is configured to emit both visible light and light in the first wavelength range. In this case, the center frequency is not particularly limited and may be within the wavelength range of visible light or within the first wavelength range. The illumination unit 5 may be a single illumination device capable of emitting both visible light and light in the first wavelength range. Alternatively, the illumination unit 5 may consist of separate illumination devices: one for emitting visible light and another for emitting light in the first wavelength range.

[0021] In a typical example of this embodiment, the first wavelength range includes at least a portion of the infrared light wavelength range, and the irradiation unit 5 is an infrared light irradiation device that irradiates infrared light. In a typical example, the irradiation unit 5 is composed of one type of LED or the like, the illumination light emitted by the irradiation unit 5 includes both visible light and infrared light, the center frequency of the illumination light emitted by the irradiation unit 5 is within the infrared light wavelength range, and the infrared light contained in the illumination light is transmitted through the contact unit 6. However, the embodiment is not limited to this example, and the irradiation unit may be provided with separate devices for irradiating visible light (e.g., a visible light LED) and a device for irradiating light in the infrared light wavelength range (e.g., an infrared light LED).

[0022] In the example shown in Figure 1, the illumination unit 5 and part of the imaging unit 4 are housed inside a box-shaped case 2. In Figure 1, the case 2 is conceptually represented by a dashed line. The space inside the case 2 is closed off at the top by the upper wall of the case 2, closed off at the bottom by the touchpad 3, and covered around the periphery by the peripheral wall of the case 2. In the example shown in Figure 1, the case 2 is configured as a box with an open bottom, and the touchpad 3 is fixed so as to close off the bottom of the case 2. For example, the case 2 is made of a material that blocks light transmission, and light is blocked by the upper wall and peripheral wall formed by the case 2.

[0023] The touchpad 3 shown in Figure 1 is the part that senses the object W1, and is the part that the object W1 is applied to from the space outside the tactile sensor 1. The touchpad 3 has a contact portion 6, which is the part that deforms upon contact with the object W1, and a peripheral portion 7 arranged around the contact portion 6. The contact portion 6 is configured to be elastically deformable, for example. The peripheral portion 7 constitutes the part of the touchpad 3 that is on the outer edge side of the contact portion 6. In the example in Figure 1, the peripheral portion 7 is connected to the base end of the contact portion 6, and the contact portion 6 protrudes downward from the peripheral portion 7.

[0024] In the example shown in Figure 1, the peripheral portion 7 is configured as a highly rigid retaining plate. The peripheral portion 7 (retaining plate) is configured in a plate shape and is the part that maintains its plate shape. In the example shown in Figure 1, the peripheral portion 7 (retaining plate) is fixed to the case 2, but the peripheral portion 7 may also be part of the case 2. The peripheral portion 7 constitutes the base end. This base end maintains a predetermined shape and its relative position and orientation to the case 2 remains unchanged, whether in a contact state where the object W1 is in contact with the contact portion 6 as shown in Figure 1, or in a natural state where no object is in contact with the contact portion 6 from the outside.

[0025] Specifically, the touchpad 3 may be configured as shown in Figure 3. In the example in Figure 3, the touchpad 3 comprises an elastic body 3A and a filter portion 3B. The elastic body 3A is a light-transmitting material that allows light to pass through, and transparent materials such as transparent materials are used. In the example in Figure 3, the elastic body 3A is made of a transparent gel material (e.g., urethane, silicone, styrene, etc.) and is configured in a predetermined hemispherical shape. One surface (bottom surface) of the elastic body 3A is covered by the filter portion 3B (reflective film 3C described later). The other surface (top surface) of the elastic body 3A is not covered by the filter portion 3B (reflective film 3C described later) and is exposed upwards.

[0026] In the representative example shown in Figure 3, the filter section 3B includes a reflective film 3C and an external light suppression film 3D. The reflective film 3C contains particles 8, which are formed by covering a flaky substrate 8A, as shown in Figure 5, with a film material 8B having a different refractive index from the substrate 8A. Figure 5 is a schematic cross-sectional view of the particles 8 contained in the reflective film 3C. The material of the substrate 8A is, for example, mica, talc, etc. The material of the film material 8B is, for example, a metal oxide such as titanium oxide or a glassy material. The particles 8 are, for example, pearl pigments. The particle size (lengthwise size) of the particles 8 is preferably 1 μm or more and 300 μm or less. The thickness (shortwise size) of the particles 8 is, for example, 1 / 100 or more and 1 / 50 or less of the particle size of the particles 8.

[0027] The reflective film 3C includes a binder. The binder is, for example, a transparent resin such as a urethane-based, PVC-based, silicone-based, polyvinyl alcohol-based, or polyolefin-based resin. The binder may also be, for example, a paint. The particles 8 are uniformly dispersed within the binder. When the reflective film 3C includes a pearl pigment and a binder, it is preferable that the pearl pigment is present in an amount of 5 to 15 parts by mass, for example 10 parts by mass, when the binder is 100 parts by mass.

[0028] Since the reflective film 3C contains pearl pigment, it is preferable that the total reflectance is 50% or less in the wavelength range greater than 400 nm and less than 760 nm. Furthermore, depending on the shape and particle size of the substrate 8A contained in the pearl pigment, it is preferable that the specular reflectance of the reflective film 3C is 4% or more and 6% or less in the wavelength range greater than 400 nm and less than 760 nm. In addition, it is preferable that the ratio of specular reflectance to total reflectance (the value obtained by dividing specular reflectance by total reflectance) of the reflective film 3C is 0.1 or more and 0.2 or less in the wavelength range greater than 400 nm and less than 760 nm. Moreover, it is preferable that the transmittance of the reflective film 3C is 3% or more in the wavelength range greater than 400 nm and less than 760 nm.

[0029] The reflective film 3C has the function of reflecting visible light and transmitting infrared light. Furthermore, the reflective film 3C has a curved structure that is convex downwards, and also has the function of maintaining the shape of the elastic body 3A. The thickness of the reflective film 3C is preferably 1 μm to 50 μm.

[0030] The external light suppression film 3D covers the outside (bottom) of the reflective film 3C. The external light suppression film 3D suppresses the intrusion of light from the outside (bottom) (for example, light in the visible light region). On the other hand, it is preferable that the external light suppression film 3D has infrared transmittance. The external light suppression film 3D is a layer that, for example, allows light in the first wavelength range to pass through and blocks the passage of light in a visible light region different from the first wavelength range (for example, the second wavelength range), and has a curved structure that is convex on the bottom. The external light suppression film 3D may be a layer of applied paint, or it may be a layer of bonded material, for example. The thickness of the external light suppression film 3D is preferably 1 μm or more and 50 μm or less.

[0031] The external light suppression film 3D is composed mainly of a resin, for example. The external light suppression film 3D includes, for example, a black pigment and a binder. The binder is a transparent resin such as a urethane-based, PVC-based, silicone-based, polyvinyl alcohol-based, or polyolefin-based resin. The binder may also be a paint, for example. The black pigment is dispersed within the binder. When the external light suppression film 3D contains a black pigment and a binder, it is preferable that the black pigment is present in an amount of 10 to 30 parts by mass, for example, 15 parts by mass, when the binder is 100 parts by mass.

[0032] To increase sensitivity, it is desirable that the filter portion 3B be thin, and that the hardness of the filter portion 3B be softer than that of the elastic body 3A. The hemispherical contact portion 6, composed of the elastic body 3A and the filter portion 3B, maintains a predetermined shape when no object is in contact with the contact surface 6A and no pressing force is applied. When an object comes into contact with the contact surface 6A and a pressing force is applied, it deforms according to that pressing force, and returns to the predetermined shape when the pressing force is released.

[0033] The filter section 3B is constructed in a film-like manner. The contact section 6 has a contact surface 6A and a back surface 6B. The contact surface 6A is one side of the contact section 6 and is the surface that contacts the object W1. The contact surface 6A is the surface facing downwards in the contact section 6 and is a curved surface that is convex downwards. In the representative example in Figure 3, the contact surface 6A is the outer surface of the external light suppression film 3D. The back surface 6B is the surface opposite to the contact surface 6A and is the back surface of the contact surface 6A. The back surface 6B is the surface facing upwards in the contact section 6. In the representative example in Figure 3, the back surface 6B is the upper surface of the elastic body 3A.

[0034] The contact portion 6 is configured to deform near the marker portion 20 depending on the contact state of the object W1 with respect to the contact surface 6A. The elements that determine the contact state of the object W1 with respect to the contact surface 6A include the shape of the portion of the object W1 that contacts the contact surface 6A, the range on the contact surface 6A that receives contact from the object W1, and the magnitude and direction of the force that the contact surface 6A receives at each position within that range.

[0035] When no object is in contact with the contact surface 6A, the contact portion 6 maintains the standard shape shown in Figure 3. When the object W1 is in contact with the contact surface 6A as shown in Figures 1 and 2, the contact portion 6 deforms according to the contact state of the object W1 with respect to the contact surface 6A. Subsequently, when the object W1 separates from the contact surface 6A and the object is no longer in contact with the contact surface 6A, it returns to the standard shape described above.

[0036] As shown in Figure 4, a marker portion 20 is provided on the contact portion 6. In the example in Figure 4, the marker portion 20 comprises a plurality of marks 20A attached to the contact portion 6, and these marks 20A form a dot pattern. The plurality of marks 20A constituting the marker portion 20 have a regularly arranged shape.

[0037] In the example shown in Figure 4, the shape of each mark 20A constituting the marker section 20 is circular. The shape of each mark 20A may be changed to a shape other than the circular shape shown in Figure 4, in which case various shapes such as polygons and ellipses may be used. Figure 4 shows an example of a marker section 20 configured as a dot pattern, but the example in Figure 4 is just one example, and the marker section 20 may be changed to other dot shapes or grid shapes different from those in Figure 4. When the marker section 20 is a grid shape, various shapes such as a lattice pattern, a triangular mesh, or a hexagonal mesh (honeycomb) may be used.

[0038] If the marker portion 20 is a dot pattern in which marks 20A or marks of a different shape from mark 20A are arranged as shown in Figure 4, each mark constituting the dot pattern may be represented by paint or the like, or by protrusions or recesses. If the marker portion 20 is a grid shape, the grid shape may be represented by paint or the like, or by protrusions or recesses. The marker portion 20 may be configured as a separate part from the filter portion 3B and the elastic body 3A, or it may be configured as a part of the filter portion 3B or as a part of the elastic body 3A.

[0039] In a representative example of this embodiment, each mark 20A in Figure 4 is represented by paint or the like on the lower surface 3E of the elastic body 3A in the contact portion 6 shown in Figure 3, and can be photographed from above the elastic body 3A. Each mark 20A is covered from below by a filter portion 3B and is sandwiched between the elastic body 3A and the filter portion 3B. Illumination light is shone on the marker portion 20 from the side opposite to the side where the object W1 contacts the contact portion 6, i.e., from above, and the marker portion 20 reflects the light incident on the marker portion 20 from the opposite side. The imaging unit 4 is capable of receiving the reflected light from the marker portion 20 and can image a predetermined range including the marker portion 20 in the contact portion 6. In a typical example, each mark 20A is sandwiched between the elastic body 3A and the reflective film 3C, and each black mark 20A is positioned above the reflective film 3C. Therefore, when the imaging unit 4 photographs a predetermined range including the marker unit 20 from above, an image is generated in which the black marks 20A appear against the background of the reflective film 3C.

[0040] The marker portion 20 is displaced in accordance with the deformation of the contact portion 6. Specifically, when the object W1 comes into contact with the contact surface 6A, the filter portion 3B and the marker portion 20, which form part of the contact portion 6, deform from their standard shape in accordance with the contact state of the object W1, and the position, orientation, and shape of the mark 20A placed on the deformed portion change.

[0041] The contact area 6 is used to image the reflective film 3C through the elastic body 3A from the other side (top side) of the elastic body 3A. The tactile sensor 1 receives reflected light from the reflective film 3C and generates an image of the reflective film 3C when deformation occurs from the reference shape according to the contact state of the object W1. The shape measurement system 10 recognizes the deformation of the contact area 6 and measures the shape of the object W1 by detecting changes in, for example, the position, orientation, and shape of the mark 20A from the image.

[0042] However, when the tactile sensor 1 recognizes the deformation of the contact area 6 from the change in the mark 20A, it is difficult to recognize deformations of the contact area 6 that are finer than the spacing of the marks 20A. As a result, the shape of the object W1 cannot be accurately measured, and the clarity of the shape of the object W1 is insufficient. Note that the spacing of the marks 20A is the spacing between adjacent dots if the marks 20A are dots, and the spacing between adjacent grids if the marks 20A are grids.

[0043] The contact portion 6 of this embodiment has a reflective film 3C that covers the lower side of the elastic body 3A, and the reflective film 3C contains particles 8 in which a scale-shaped base material 8A is covered with a film material 8B having a different refractive index from the base material 8A. Therefore, if deformation of the contact portion 6 occurs that is finer than the spacing of the marks 20A, the position and orientation of the particles 8 change according to the deformation, and the reflectance (e.g., specular reflectance) of the deformed portion changes. The shape measurement system 10 can clearly measure the shape of the object W1 from an image of the reflective film 3C that includes the change in reflectance.

[0044] The contact portion 6 configured in this way allows light in the first wavelength range to pass through, for example, in part or all of the area other than the marker portion 20, and blocks the passage of light in a second wavelength range that is different from the first wavelength range. The first wavelength range includes, for example, at least a portion of the wavelength range of infrared light or ultraviolet light, and the second wavelength range is, for example, the entire wavelength range other than the first wavelength range. Preferably, the second wavelength range includes at least a portion of the wavelength range of visible light.

[0045] In this specification, the visible light wavelength range is defined as the range greater than 400 nm and less than 760 nm. The range between 760 nm and 1000 nm is defined as the infrared light range. The range between 10 nm and 400 nm is defined as the ultraviolet light range. In a typical example, the first wavelength range includes at least a portion of the infrared light wavelength range. It is desirable that the lower limit of the first wavelength range is greater than the lower limit of the infrared light wavelength range. It is desirable that the lower limit of the first wavelength range is smaller than the central wavelength of the illumination light emitted by the irradiation unit 5. The central wavelength of the illumination light emitted by the irradiation unit 5 may be, for example, 850 nm or 940 nm. In this case, the lower limit of the first wavelength range can be, for example, 760 nm. Of course, the lower limit may be a value other than this. The first wavelength range may be the entire range greater than or equal to the lower limit of the first wavelength range, and an upper limit may be set. If an upper limit is set for the first wavelength range, it is desirable that this upper limit be greater than the central wavelength of the illumination light emitted by the irradiation unit 5.

[0046] 2. About the shape measurement system 10 The shape measurement system 10 shown in Figure 2 is a system that uses a tactile sensor 1 and measures the shape of an object W1 using the image generated by the tactile sensor 1. The shape measurement system 10 comprises the tactile sensor 1 and a control unit 11 that controls the entire shape measurement system 10.

[0047] The control unit 11 comprises a CPU 12 as an information processing unit, a ROM 13 and RAM 14 as storage units, and an input / output port 15. The CPU 12 can perform various calculations and controls. For example, the CPU 12 can execute various processes to control the entire shape measurement system 10 and can output the processing results as predetermined control signals. The ROM 13 stores control programs for controlling the shape measurement system 10. The RAM 14 temporarily stores various information necessary for the operation of the shape measurement system 10. The ROM 13 and RAM 14 are merely examples, and other types of storage media may be used. The input / output port 15 is an interface used for communication, and the control unit 11 can communicate with the imaging unit 4, the illumination unit 5, etc., via the input / output port 15.

[0048] In the shape measurement system 10, the illumination unit 5 emits illumination light or stops illumination based on a command from the CPU 12. Furthermore, in the shape measurement system 10, the imaging unit 4 starts capturing images of a predetermined range including the marker unit 20 on the contact unit 6 based on a command from the CPU 12, and the image generated by the imaging unit 4 is provided to the CPU 12.

[0049] 3. Sensing method and shape measurement method The shape measurement system 10 can perform a sensing method and a shape measurement method using the tactile sensor 1. When the shape measurement system 10 performs the sensing method, the CPU 12 performs shape measurement control according to a program pre-stored in the memory unit, and performs the shooting process and the analysis process. When the shape measurement system 10 performs the shape measurement method, in addition to the shooting process and the analysis process included in the sensing method, it also performs a measurement process.

[0050] For example, the CPU 12 executes the shape measurement control described above when predetermined start conditions are met, and performs the shooting process, analysis process, and measurement process. The above start conditions may be that a predetermined operation is performed on an operating device (not shown) provided on the shape measurement system 10, that power supply to the control unit 11 is started, or other conditions.

[0051] When the CPU 12 performs shape measurement control in response to the fulfillment of the above start conditions, it first performs a shooting process and causes the imaging unit 4 to take a photograph. In the shooting process, the CPU 12 gives instruction information to the illumination unit 5 to irradiate, and the CPU 12 gives instruction information to the imaging unit 4 to take a photograph. Therefore, in the shooting process, while the illumination unit 5 irradiates illumination light, the imaging unit 4 photographs a predetermined range including the marker portion 20 in the contact portion 6 according to the instruction information. The timing at which the imaging unit 4 generates an image according to the above information from the CPU 12 may be immediately after the CPU 12 gives the instruction information to the imaging unit 4, or at each timing at regular intervals after the CPU 12 gives the instruction information to the imaging unit 4, or at any other timing.

[0052] When the object W1 is in contact with the contact surface 6A, and the above-described imaging process is performed, the contact portion 6 will be in a state where it allows light in the first wavelength range to pass through and blocks light in the second wavelength range, and the reflective film 3C and marker portion 20 will be reflecting light incident from above. The imaging unit 4 will receive the reflected light from the reflective film 3C and marker portion 20 and the light in the first wavelength range, and an image of the reflective film 3C and marker portion 20 in the above-described contact state can be generated.

[0053] Furthermore, when the imaging unit 4 takes a photograph, if the object W1 is within the imaging range, whether in contact or non-contact, the light in the first wavelength range emitted from the illumination unit 5 passes through the contact unit 6 and illuminates the object W1, and the reflected light from the object W1 due to this illumination passes through the contact unit 6 and can be received by the imaging unit 4. Therefore, in the imaging process, the imaging unit 4 can generate a photographic image that shows the object W1 as if it were photographed from above, whether in contact or non-contact.

[0054] Then, the CPU 12 analyzes the captured images obtained by this sensing method to measure the shape of the object W1, etc. Specifically, after acquiring captured images by executing the above-described shooting process, the CPU 12 performs an analysis process. In the analysis process, the CPU 12 extracts images of the reflective film 3C, the marker portion 20, and the object W1 from the captured images generated in the shooting process. When the CPU 12 performs the analysis process, it may also use all of the image information generated by the imaging unit 4 to extract images of the reflective film 3C, the marker portion 20, and the object W1 from the images generated by the imaging unit 4.

[0055] The analysis step may include generating an image from the image information generated by the imaging unit 4 in which the influence of "some light" has been suppressed or removed, and extracting an image of the reflective film 3C, an image of the marker unit 20, or an image of the object W1 from this image. When suppressing or removing the influence of "some light" in the analysis step, "some light" may be light in a predetermined wavelength range other than the first wavelength range, or it may be light in a predetermined wavelength range within the first wavelength range. For example, if "some light" is "light in a predetermined wavelength range other than the first wavelength range," then generating an image in which the influence of this "some light" has been suppressed or removed will relatively produce an image that emphasizes the light in the first wavelength range. For example, in the analysis step, the CPU 12 may extract an image of the reflective film 3C, an image of the marker unit 20, and an image of the object W1 from an image that uses only the R component image information generated by multiple R elements, excluding the G component image information generated by multiple G elements and the B component image information generated by B elements of the imaging unit 4 from the image information generated by the imaging unit 4. In this example, if multiple R elements are capable of receiving light in a wavelength range that includes at least a portion of the first wavelength range, and multiple G elements and multiple B elements are incapable of receiving light in the first wavelength range, then "light in a predetermined wavelength range other than the first wavelength range" can be removed. Alternatively, if the density of each RGB component in each pixel included in the captured image generated by the imaging unit 4 is represented by 256 gradations, the density of the G and B components of each pixel may be set to 0 or greatly reduced, and other filtering processes may be performed on the image information generated by the imaging unit 4 to generate an image in which light in a predetermined wavelength range other than the first wavelength range is reduced or removed.

[0056] In the measurement process, the shape of the object W1 is determined based on the image generated during the analysis process. Specifically, in the measurement process, the image generated by the imaging unit 4 is analyzed to determine the shape of the object W1. For example, the image of the reflective film 3C that has been deformed from its natural state by contact with the object W1 is an image of the reflective film 3C that reflects the shape of the object W1, and the shape of the object W1 that is in contact with the contact part 6 is detected from this image. Furthermore, various known methods can be used to detect the shape of the object W1 that is in contact with the contact part 6 to which the marker part 20 is attached, from the image of the marker part 20 which is configured as a dot pattern or a grid pattern. For example, methods disclosed in Japanese Patent Application Publication No. 2005-257343, International Publication No. 2005 / 085785, Japanese Patent Application Publication No. 2005-114715, etc., may be used, or other known methods may be used. For example, the CPU 12 may analyze the image information obtained in the above-described shooting process and measure the size of the contact area in the contact area 6 where the object W1 makes contact and the deformation shape after contact, or it may measure the magnitude and direction of the force applied to each position of the contact area 6 by the object W1. The control unit 11 corresponds to an example of a shape measurement unit and functions to analyze the image generated by the imaging unit 4 and measure the shape of the object W1. Furthermore, the CPU 12 can also measure the external shape, size, position, etc. of the object W1 from an image of the object W1 taken directly based on the light transmitted through the contact area 6.

[0057] 4. Experiment An experiment was conducted to capture and evaluate images of an object using a tactile sensor equipped with a contact portion. In the example, the contact portion 6 of the first embodiment (a contact portion having a reflective film 3C containing pearl pigment and binder) was used. As a comparative example, an experiment was also conducted using a contact portion in which the reflective film was composed of a white film made of titanium oxide. A 100-yen coin was used as the object, and the object was brought into contact with the contact portion from the bottom side to deform the contact portion. Figure 6 is the captured image of the comparative example. Figure 7 is the captured image of the example. In the captured image of the comparative example, the object could hardly be recognized. In the captured image of the example, the object could be clearly recognized, and even fine irregularities could be recognized. Therefore, it was found that the shape of the object can be clearly captured by using the contact portion of the first embodiment.

[0058] 5. Examples of effects The contact portion 6 of the tactile sensor 1 in this first embodiment is equipped with a translucent elastic body 3A. One side of the elastic body 3A is covered with a reflective film 3C, and the other side is not covered with the reflective film 3C. The reflective film 3C contains particles 8, which are made by covering a flaky base material 8A with a film material 8B having a different refractive index from the base material 8A. The contact portion 6 is used to image the reflective film 3C through the elastic body 3A from the other side of the elastic body 3A. By performing imaging using a reflective film 3C with this configuration, a clear image of the contact portion 6 that has been deformed upon contact with the object W1 can be captured due to the change in reflectivity accompanying the change in particles 8. For example, it is possible to recognize deformation of the reflective film 3C (shape of the object W1) that is finer than the mark 20A of the marker portion 20.

[0059] In the contact portion 6 of the tactile sensor 1 of this first embodiment, it is preferable that the ratio of specular reflectance to total reflectance of the reflective film 3C is 0.1 or more and 0.2 or less in the wavelength range greater than 400 nm and less than 760 nm. This configuration makes it easier to capture a clear image of the reflective film 3C.

[0060] In the contact portion 6 of the tactile sensor 1 of this first embodiment, it is preferable to have an external light suppression film 3D that covers the outside of the reflective film 3C and suppresses the intrusion of light from the outside. With such a configuration, imaging with reduced influence of external light becomes possible, and observation of the reflective film 3C and the like becomes easier.

[0061] In the contact portion 6 of the tactile sensor 1 of this first embodiment, the external light suppression film 3D preferably has infrared transmittance. With this configuration, measurements using infrared light become possible, such as measuring the temperature of an object W1 or measuring the distance to the object W1. In addition to illuminating with illumination light, the object W1 can also be heated with infrared light. Furthermore, by constructing the contact portion 6 with thermochromic rubber that changes color according to temperature, the temperature of the contact portion 6 can be measured by photographing the contact portion 6 with the imaging unit 4 and analyzing the obtained image of the contact portion 6 to evaluate its color.

[0062] In the contact portion 6 of the tactile sensor 1 of this first embodiment, the particle size of the particles 8 is preferably 1 μm or more and 300 μm or less. This configuration makes it easier to capture a clear image of the reflective film 3C.

[0063] <Other Embodiments> This disclosure is not limited to the embodiments described above and in the drawings, and the technical scope of this disclosure also includes, for example, the following embodiments.

[0064] In the embodiment described above, the irradiation unit 5 irradiates illumination light containing light in the first wavelength range from above (inside) to the contact unit 6. However, instead of this configuration, or in addition to this configuration, an irradiation unit similar to the irradiation unit 5 may be provided to irradiate illumination light onto the contact unit 6 from below (outside).

[0065] In the embodiment described above, the irradiation unit 5 is configured to irradiate illumination light that includes light in the first wavelength range, but the irradiation unit 5 may also be configured to irradiate only visible light.

[0066] In the embodiments described above, the entire elastic body 3A is composed of gel, but it may be sealed with a sealing film. Alternatively, a space may be formed inside the sealing film such that a liquid such as water or air is present instead of the gel in all or part of the elastic body 3A. In this case, the elastic body 3A surrounding the space is preferably elastic and viscous.

[0067] In the embodiment described above, a marker portion 20 was provided on the contact portion 6, but a configuration in which an image of the reflective film 3C is acquired without providing the marker portion 20 is also possible.

[0068] This disclosure is not limited to the embodiments detailed above, and various modifications or alterations are possible. [Explanation of symbols]

[0069] 1: Tactile sensor 2: Case 3: Touchpad 3A: Elastic body 3B: Filter section 3C: Reflective film 3D: External light suppression film 3E: Lower surface of the elastic body 4: Imaging Department 5: Irradiation area 6: Contact area 6A: Contact surface 6B: Reverse side 7: Peripheral area 8: Particles 8A: Base material 8B: Membrane material 10: Shape Measurement System 11: Control Unit 12: CPU 13: ROM 14: RAM 15: Input / Output Ports 20: Marker Department 20A: Mark W1: Object X: Optical axis

Claims

1. A contact part used in a tactile sensor that comes into contact with an object, Equipped with a translucent elastic material, The elastic body has one surface covered with a reflective film and the other surface not covered with the reflective film. The reflective film comprises particles in which a scale-like substrate is covered with a film material having a different refractive index from the substrate. A contact portion used for imaging the reflective film through the elastic body from the other side.

2. The contact portion according to claim 1, wherein the reflective film has a ratio of specular reflectance to total reflectance of 0.1 or more and 0.2 or less in the wavelength range greater than 400 nm and less than 760 nm.

3. The contact portion according to claim 1 or claim 2, further comprising an external light suppression film that covers the outside of the reflective film and suppresses the intrusion of light from the outside.

4. The contact portion according to claim 3, wherein the external light suppression film has infrared transmittance.

5. The contact portion according to claim 1 or claim 2, wherein the particle size of the aforementioned particles is 1 μm or more and 300 μm or less.

Images