Tactile sensor

Abstract

The present disclosure provides a sensing device, a tactile sensing device, and a tactile sensor. The sensing device includes: a photosensitive sensor; a pinhole array structure located on the photosensitive sensor; an elastomer layer located on a side of the pinhole array structure away from the photosensitive sensor; a reflective layer located on a side of the elastomer layer away from the pinhole array structure; and a light source located between the reflective layer and the pinhole array structure.

Description

Technical Field

[0001] The present disclosure relates to vision-based tactile sensors, particularly for sensing three-dimensional surface deformation and force distribution in a contact area. Background Art

[0002] Tactile sensors are currently used in many fields, such as robotics and medical surgery. For example, for a grasping operation system, a tactile sensor is a necessary component to generate effective feedback to maintain a stable grasp during movement.

[0003] In recent decades, various types of tactile sensors with different conversion methods have been widely developed, including capacitive, piezoelectric, and piezoresistive. They cover a wide range from micro to macro and have a wide range of applications. However, due to their high complexity in mechanical structure, readout circuit design, and interface, they lack the ability of high-resolution spatial mapping and three-dimensional measurement.

[0004] Vision-based tactile sensors have thrived in various robotic systems, such as Gelforce, FingerVision, Gelsilight, due to their advantages of easy fabrication, high resolution, and multi-axis deformation sensing. They take full advantage of the current progress in the development of CMOS image sensors, such as low cost, high resolution, fast response, and miniaturized size. In particular, since the readout circuit of the image sensor is mature and integrated with the sensor, it is easy to achieve the high-density spatial mapping ability. However, due to the relatively large size, high cost, and repeatability issues, vision-based tactile sensors have not been applied to existing industrial robots.

[0005] For the development of the next generation of vision-based tactile sensors, miniaturization, low cost, simple fabrication, and robust adaptability are required. Inspired by the compound eye structure composed of an array of closely arranged independent visualization units, the present invention provides a solution for a thin skin-like tactile sensor, which can provide a high spatial density of tactile mapping functions for surface deformation and contact force distribution. Summary of the Invention

[0006] Inspired by compound eyes, a vision-based tactile sensing device is developed for grippable robotic applications and other applications that require touch information. There is an elastomer layer coated with a flexible reflective film that forms the top layer, where markers are coated on the bottom of the reflective film. The markers are typically multiple arrays of circles or other random structures that can be optimized for easy image processing. The reflective layer serves as a contrast-enhancing background for marker image extraction during image processing and also serves as a protective layer for the device. Optionally, an additional protective layer can be added between the elastomer layer and the reflective layer or on top of the reflective layer. The deformation of the markers is captured by an optical imaging system combined with a compound eye excitation lens structure (middle layer) and a CMOS sensor (bottom layer). The middle layer consists of a microfabricated lens array located under the elastomer layer. There can be another rigid transparent layer between the elastomer and the lens structure to ensure that the elastomer does not change at the interface of the lens and the elastomer. The bottom layer is where the CMOS image sensor chip is located. The CMOS image sensor chip captures the movement of the markers and sends the signal to the image processing unit through an interface circuit. In addition to the above main components, a light source will be appropriately placed beside each lens or at the edge of the system to provide imaging illumination. The light source can be an LED, an optical fiber, or other types. The sensor images the three-dimensional movement and shape change of the markers through a separate sensing unit or through cross-referencing of images from adjacent sensing units, from which the deformation and slip rate distribution of the entire surface can be derived. Thus, the contact force at the surface can also be calculated. The resolution of the sensor depends on the pixel size of the CMOS imager and the optical magnification of the lens system. The sensor thickness depends on the height of a single optical unit and varies from a few hundred micrometers to several centimeters according to the image magnification. The sensing area of the system is typically equal to the size of the CMOS imager (in the range of mm to cm), and technically, a CMOS imager array for large-area sensing can be implemented. The lens system is fabricated using microfabrication techniques or 3D printing or other appropriate methods to ensure high precision, reliability, repeatability, and low cost.

[0007] According to one aspect of the present invention, there is provided a sensing device, comprising: a photosensitive sensor; a pinhole array structure located on the photosensitive sensor; an elastomer layer located on a side of the pinhole array structure away from the photosensitive sensor; a reflective layer located on a side of the elastomer layer away from the pinhole array structure; and a light source located between the reflective layer and the pinhole array structure.

[0008] In some embodiments, the pinhole array structure comprises holes in circular, rectangular, triangular, or pentagonal shapes arranged in a grid.

[0009] In some embodiments, the light source comprises a light-emitting diode or a light-emitting fiber.

[0010] In some embodiments, the pinhole array structure includes a set of holes, and the light source includes a set of illumination modules adhesively attached adjacent to the periphery of each hole, or the light-emitting fibers are distributed in a network structure between the respective holes.

[0011] In some embodiments, the sensing device further includes a marker located on a side of the elastomeric layer away from the pinhole array structure.

[0012] In some embodiments, the marker is a color patch distributed in an array or irregularly in the form of a grid, hexagon, or triangle pattern, and the deformation of the elastomer caused by contact with an external entity causes the marker to change its position relative to the photosensitive sensor so that the photosensitive sensor detects the displacement of the marker.

[0013] In some embodiments, the sensing device further includes a transparent rigid layer located between the elastomeric layer and the pinhole array structure.

[0014] In some embodiments, the sensing device further includes a first transparent protective layer located on one side of the reflective layer.

[0015] In some embodiments, the sensing device further includes a second transparent protective layer located on the other side of the reflective layer relative to the first transparent protective layer.

[0016] According to one aspect of the present disclosure, there is provided a tactile sensing device, including: a complementary metal oxide semiconductor sensor; at least one set of pinhole array structures located on the complementary metal oxide semiconductor sensor; an elastomeric layer located on a side of the pinhole array structure away from the complementary metal oxide semiconductor sensor; a reflective layer located on a side of the elastomeric layer away from the pinhole array structure; and a light source located between the reflective layer and the pinhole array structure.

[0017] In some embodiments, the pinhole array structure includes round holes arranged in a grid and support square holes facing away from the round holes on the side of the pinhole substrate.

[0018] In some embodiments, the tactile sensing device further includes a wall between adjacent support square holes in the pinhole substrate, wherein the wall is configured to prevent light entering a square hole from entering an adjacent square hole covering a photosensitive area group.

[0019] In some embodiments, the movement of the marker received on the elastomer layer is recorded by the complementary metal oxide semiconductor sensor, and the movement is processed to determine deformation. Wherein, by collecting pictures of the elastomer layer when it is deformed under different forces, adding the correction of a standard force sensor, and deriving a force distribution map through an algorithm model based on the deformation, or calculating the force distribution map through the known Young's modulus of the elastomer layer.

[0020] In some embodiments, the movement is cross-referenced with the information received from the current capture position of the marker and a static image of the captured entity without depression to determine the deformation distribution of the surface to which the complementary metal oxide semiconductor sensor is attached, or a three-dimensional force distribution map is obtained by obtaining deformation information in the vertical direction in adjacent or different array hole fields of view to determine the deformation distribution of the surface to which the complementary metal oxide semiconductor sensor is attached.

[0021] According to another aspect of the present disclosure, a method for manufacturing a tactile sensor is also provided, including: providing a pinhole array structure on a monolithic photosensitive sensor; providing an elastomer layer on the pinhole array structure, wherein the elastomer layer includes markers on the surface of the elastomer layer; providing a reflective layer on a side of the elastomer layer away from the pinhole array structure; and providing a light source between the reflective layer and the pinhole array structure.

[0022] In some embodiments, the pinhole array structure includes optical channels.

[0023] In some embodiments, the markers form a contrast with the reflective layer

[0024] In some embodiments, the markers are distributed according to a pattern.

[0025] In some embodiments, the pinhole array structure includes a first surface etched into a circular hole array and a second surface etched into a square hole array. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1A and Figure 1B shows a schematic diagram of a tactile sensor device inspired by compound eyes using a pinhole structure with different light source distributions;

[0027] Figure 2 is a top view schematic diagram showing a pinhole array structure;

[0028] Figure 3 is a schematic diagram of a tactile sensor device inspired by compound eyes using a convex lens array;

[0029] Figure 4 is a top view schematic diagram showing a structure based on a convex lens array;

[0030] Figure 5 is a schematic diagram showing a unit tactile sensor device using a pinhole-based lens structure.

[0031] Figure 6 is a schematic diagram showing a unit tactile sensor device using a convex lens.

[0032] Figure 7A and Figure 7B is a view showing a multi-CMOS component tactile sensor according to an exemplary embodiment of FIG. 1.

[0033] Figure 8A and Figure 8B is a view showing a multi-CMOS component tactile sensor according to Figure 3 an exemplary embodiment.

[0034] Figure 9 is a vision-based tactile sensor that combines the structure in FIG. 7 with another elastomer.

[0035] Figure 10 is a vision-based tactile sensor that combines the structure in FIG. 8 with another elastomer.

[0036] Figure 11 is an embodiment of a flexible-optical-based tactile sensor that combines the structure of FIG. 7 with another elastomer.

[0037] Figure 12 Shows a second embodiment of a flexible-optical-based tactile sensor using a pinhole structure.

[0038] Figure 13 is an embodiment of a flexible-optical-based tactile sensor that combines the structure in FIG. 8 with another elastomer.

[0039] Figure 14 Shows a second embodiment of a flexible-optical-based tactile sensor using a micro convex lens structure. Detailed Description of the Invention

[0040] The present invention will be described below through a detailed description of embodiments.

[0041] In Figure 1A , a schematic diagram of a tactile sensor based on a pinhole array is shown. The device includes a reflective layer 1 for illumination reflection, an elastomer layer 4 with markers 2 on top, one or a series of LEDs 3 for providing illumination for imaging, a pinhole-based lens structure 5, and a CMOS (complementary metal oxide semiconductor) sensor 6. One or a series of LEDs 3 will provide illumination to the elastomer 4, and they are located on the (one or more) sides of the elastomer 4.

[0042] In this embodiment, the reflective layer 1 is a flexible layer with a high light reflectivity, and its shape can be changed according to an external touch. The material of the reflective layer 1 can be silicone resin, parylene C, polyimide, and other polymers, other inorganic materials, as long as it can be deformed by the applied force in combination with the underlying elastomer. Additionally, the reflective layer 1 can be used as a protective layer. Alternatively, another protective layer can be added on top of or beneath the reflective layer 1. The protective layer is used to protect the tactile sensor from external environmental influences, including but not limited to contact wear, tearing, moisture, light, strong impact, and chemical effects.

[0043] For example, if an additional protective layer is added, the reflective layer 1 is fixed to the protective layer, where the protective layer is transparent. The protective layer is also a thin flexible film, typically a plastic film with a thickness of a few micrometers. For example, the protective layer can be surface-hardened parylene C, a transparent polymer film commonly used as a protective layer. The protective layer can be attached to the elastomer layer 4.

[0044] One or a series of LEDs 3 are fixed on any side (or multiple sides) of the elastomer layer 4. In this embodiment, one LED is used for a specific sensing area, where the LED can provide sufficient light to make all the markers visible. The present invention uses LEDs that can emit visible light. In this embodiment, white LEDs are used. Other types of LEDs with different wavelengths can also be used, and other types of lighting devices can also be employed. In Figure 1B which, the LEDs are arranged at the edge of the pinhole unit.

[0045] The elastomer layer 4 is transparent and elastic. For different tactile sensing requirements, the thickness and material of the elastomer layer are different. In this embodiment, the material of the elastomer layer 4 is PDMS (polydimethylsiloxane), and the thickness of the elastomer layer is 1.5 mm. The elastomer layer 4 changes its shape according to an external contact. The markers above will indicate the deformation caused by the touch, and if the Young's modulus is known, the force distribution can be derived. Another way to obtain the force distribution is to collect a large amount of data on the deformation of the elastomer and calibrate it through a standard force sensor to provide a three-dimensional force distribution map.

[0046] Marker 2 is coated on the elastomer 4, and the movement of Marker 2 activated by the applied force is captured for further image processing. The thickness of Marker 2 should be very thin and negligible compared to the thickness of the elastomer. Marker 2 can be one or a series of points, circles or other random patterns as long as it is suitable for image recognition and image stitching operations. In some embodiments, Marker 2 consists of a circular array. Marker 2 can be any material that can be coated on the reflective layer 1 or the elastomer layer 4. The marker should produce a good contrast with the reflective layer for easy imaging. In this embodiment, the marker is made of copper dots.

[0047] The pinhole-based lens structure 5 is disposed below the elastomer layer 4 and fixed to the elastomer layer 4. A transparent rigid layer can be placed between the elastomer and the lens structure to form a good interface between the elastomer and the lens structure. In this embodiment, the lens structure is formed on both sides such that one side is etched to form an array of circular holes (see the circular holes 9 in Figure 2 , while the other side is etched to form an array of deep square holes (see the square holes 10 in Figure 2 ). In this embodiment, the diameter and height of the circular holes, and the side length and height of the square holes can typically be 32 μm, 10 μm, 500 μm and 500 μm respectively. The sizes of the pinholes and the square holes can vary according to the imaging requirements. Both holes are fabricated by microfabrication. The pinhole-based lens structure 5 is fixed on top of the CMOS sensor 6.

[0048] When the top side of the reflective layer 1 is excited by the applied force, Marker 2 deforms, and the movement of Marker 2 will be continuously recorded by the CMOS sensor 6, and then the image will be processed for further deformation and force mapping. The illumination will be provided by the LED 3. Through such an embodiment, a very thin, e.g., a few millimeters thick, compound eye-inspired tactile sensor is obtained at low cost using a pinhole-based lens structure.

[0049] In Figure 2 , it is shown according to Figure 1ATop view of the pinhole-based lens structure 5. The pinhole-based lens structure 5 consists of an array of circular holes 9 and an array of square holes 10. The array is six by ten, which means there are sixty circular holes 9 and square holes 10 respectively on the top and bottom sides of the structure. In this embodiment, the pinhole-based lens structure 5 is made of silicon. When viewed from the top view, each circular hole is located at the center of the square hole. In some embodiments, the circular hole may not be located at the center of the square hole. The diameter of the circular hole ranges from one micron to one hundred microns, while the height of the circular hole and the square hole varies from dozens of microns to several millimeters according to sensing requirements. The pinhole-based lens structure 5 is manufactured by microfabrication, in which the array of circular holes 9 is first etched from the top, and then the array of square holes 10 is etched from the back side to form the optical channels. Different manufacturing methods (such as 3D printing, etc.), processes, and sequences can also be used for this structure. Silicon wafers can be used as the manufacturing material in this process. In this embodiment, the distance from one square hole to the adjacent square hole is typically 100μm, while according to sensing requirements, it can be in the range of several microns to millimeters. The walls between the square holes ensure that the light entering one square hole does not affect other square holes. In addition to this typical pinhole-based lens structure 5, in the case where one circular hole corresponds to one square hole, the pinhole-based compound eye lens structure 5 can also be: one circular hole and one square hole, or a circular hole-square hole array different from the rectangular array form, or other array forms with more or fewer holes. In addition, the circular hole (as a pinhole) can be of different shapes, such as square, oval, hexagonal, etc. The square hole (as an image isolation chamber) can have different shapes, such as circular, oval, hexagonal, etc.

[0050] In Figure 3 it shows a schematic diagram of a tactile sensor based on a micro-convex lens. Except that the micro-convex lens array 8 is located on the supporting square hole array 7 instead of the structure composed of holes on both sides, most of the structure is the same as that in Figure 1A the embodiment. One lens corresponds to one supporting square hole, and the walls between the supporting square hole arrays 7 can still block the light diffraction from other units. In this embodiment, each lens is manufactured by microfabrication, and is first assembled with the supporting square hole array 7, and then an elastomer layer 4 is added on top of the micro-convex lens array 8.

[0051] Figure 4 It shows Figure 3Top view of a tactile sensor based on microlenses. The compound eye structure based on convex lenses consists of a microlens array 8 and a supporting square hole array 7. The sizes of the convex lenses vary, and the height of the square holes varies from dozens of micrometers to several millimeters according to sensing requirements. The microfabricated convex lenses are mounted on the etched supporting square holes (other hole shapes can also be used according to application needs). Different manufacturing methods, processes, and sequences can also be adopted. In this embodiment, the distance from one square hole to an adjacent square hole is typically 100 μm, and according to sensing requirements, it can range from a few micrometers to millimeters. The walls between the square holes ensure that the light entering one square hole does not affect other square holes. In this embodiment, the supporting square hole array 7 is made of silicon. The array remains six by ten, which means there are sixty individual lenses on top of sixty supporting square holes. In addition to the above array forms of the microlens array 8 and the supporting square hole array 7, as long as one convex lens corresponds to one supporting hole, the compound eye structure based on the convex lens array can also be one convex lens on one supporting square hole, or an array form of lenses on square holes different from the rectangular array form, or an array form with different numbers of convex lenses.

[0052] Figure 5 is a schematic diagram showing a unit tactile sensor device using a pinhole-based lens structure. Except for having only one unit of the pinhole-based lens structure, most of the structure is the same as Figure 1A The same. The marker 2 can be a single dot pattern, a circle array, or other random patterns that can be further processed. The device includes a reflective layer 1 for illumination reflection, an elastomer layer 4 on top of which the marker 2 is located, one or a series of LEDs 3, a pinhole-based lens structure 5, and a CMOS sensor 6. The unit of the pinhole-based lens structure 5 is composed of the same circular holes and square holes as Figure 2 in.

[0053] Figure 6 is a schematic diagram showing a unit tactile sensor device using one convex lens. Except for having only one microlens 8 with one supporting square hole 7, most of the structure is the same as Figure 3 The same. The device consists of a reflective layer 1, an elastomer layer 4 on top of which the marker 2 is located, one or a series of LEDs 3, a microlens 8 with one supporting square hole 7, and a CMOS sensor 6. The unit based on the convex lens structure is composed of the microlens 8 and the supporting square hole 7.

[0054] For a better understanding of the following figures (from Figure 7 to Figure 14 ), in the following figures, the reflective layer 1, the marker 2, and one or a series of LEDs will be omitted, and these components play the same role as the components in Figure 1.

[0055] Figure 7A and Figure 7BSide and top views of schematic diagrams of assembling multiple CMOS sensors according to the Figure 1A embodiment are shown. The basic structure of the tactile sensor is the same as that in Figure 1A , except that the elastomer layer 4 covers all four CMOS sensors 6 and the pinhole-based lens structure 5. According to this embodiment, different combinations of multiple CMOS sensors can be obtained. The reflective layer and markers also cover all the sensing areas, like the elastomer layer 4, while the LED can provide illumination, and then it becomes a tactile sensor with a larger sensing area.

[0056] Figure 8A and Figure 8B Side and top views of schematic diagrams of assembling multiple CMOS sensors according to the Figure 3 embodiment are shown. The basic structure of the tactile sensor is the same as that in Figure 3 , except that the elastomer layer 4 covers all four CMOS sensors 6, the support square hole array, and the micro-convex lens array 8. According to this embodiment, different combinations of multiple CMOS sensors can be obtained. The reflective layer and markers also cover all the sensing areas, like the elastomer layer 4, while the LED can provide illumination. Figure 8A and Figure 8B The combination of the above components is a tactile sensor with a larger sensing area.

[0057] Figure 7A , Figure 7B , Figure 8A and Figure 8B The structures in also provide flexibility to the system because there are gaps between the CMOS sensors and the structures on top of the CMOS sensors are elastic. To enhance the reliability and stability of the system, an additional flexible or stretchable layer can be bonded to the bottom of the CMOS sensors as follows.

[0058] In Figure 9 , a schematic diagram of the combination between multiple tactile sensors using a pinhole-based lens structure and another elastomer layer 11 is shown, and the elastomer layer 11 connects the pinhole lens structure and the CMOS sensors. The basic structure of this embodiment is the same as that in Figure 7, except that there is an elastomer layer 11 connecting the CMOS sensors 6. In this structure, the elastomer layer 4 still covers all the CMOS sensors 6, and the elastomer layer 11 is filled into the gap between the adjacent pinhole-based lens structures 5 and the CMOS sensors 6. When the CMOS and the above structures are still rigid, the elastomer layer 4 and the elastomer layer 11 together play an enabling role to make the structure flexible. According to this embodiment, any other flexible array other than 2×2 can also be designed and manufactured.

[0059] In Figure 10In [description], multiple tactile sensors using a structure based on microlenses and an elastomer layer 11 are shown. The elastomer layer 11 connects the CMOS sensor 6 with a structure based on convex lenses and a square hole array structure 7. Except that the elastomer layer 11 fills the gap between adjacent structures 7 based on convex lens arrays and the CMOS sensor 6, the basic structure of this embodiment is the same as that in FIG. 8. In this embodiment, the elastomer layer 4 and the elastomer layer 11 provide the flexibility as described in Figure 9 . According to this embodiment, any other flexible array other than 2×2 can also be designed and manufactured. This embodiment is different from the one using the microlens structure in Figure 9 .

[0060] Figure 11 An embodiment is shown, which shows multiple tactile sensors using a combination between a pinhole lens structure, the CMOS sensor 6, and a bottom elastomer layer 12. Compared with the embodiment in Figure 9 , the difference here is that the elastomer layer 12 is arranged at the bottom of the device, and there may or may not be an additional elastomer between adjacent pinhole-based lens structures 5 and the CMOS sensor 6. In this structure, the elastomer layer 4 covering the top of the entire sensing area and the elastomer layer 12 at the bottom give the device greater flexibility and compliance with the human skin.

[0061] Figure 12 An embodiment of combining multiple tactile sensors is shown. The multiple tactile sensors use a pinhole-based lens structure, an elastomer layer 13, the CMOS sensor 6, a pinhole-based lens structure 5, an elastomer layer 4 on top of each tactile sensor, and an elastomer layer 13 at the bottom of the device connecting all tactile sensors. Figure 12 The appearance during deformation is shown. In this embodiment, four tactile sensors are arranged on the elastomer layer 13. The distribution of the tactile sensors is different for different conditions. Compared with the embodiment in Figure 11 , there is a separate elastomer layer 4 for each tactile sensor unit, and only the elastomer layer 13 is the elastomer layer connecting all flexible tactile sensor units.

[0062] Figure 13 An embodiment is shown, which shows a combination between multiple tactile sensors using a structure based on microlenses, the CMOS sensor 6, an elastomer layer 12 at the bottom of the device, a square hole structure array 7, a microlens array 8, and an elastomer layer 4 at the top of the device. Compared with the embodiment in Figure 10 , the difference here is that the elastomer layer 12 is arranged at the bottom of the device, and there may or may not be an additional elastomer between adjacent supporting square hole structure arrays 7 and the CMOS sensor 6. In this structure, the elastomer layer 12 gives the device more flexibility and adaptability to the human skin, as described in Figure 11as shown

[0063] Figure 14 An embodiment is shown which shows a plurality of tactile sensors using a combination of a microlens-based structure, a CMOS sensor 6, an array of square hole structures 7, a microlens array 8, an elastomer layer 4 on top of each tactile sensor, and an elastomer layer 13 at the bottom of the device that connects all the tactile sensors. Each tactile sensor on the elastomer 13 is flexible and contributes to the flexibility of the entire device. In this embodiment, four tactile sensors are distributed on the elastomer layer 13. Other numbers or distributions of flexible sensors can be designed and fabricated in this method.

[0064] The tactile sensor of the present invention has the following advantages: (1) infinite depth of focus, (2) wide field of view, and (3) simple and fast image processing, and can be used for three-dimensional surface profile displacement measurement. In view of the fact that the pinhole lens array requires a high illumination intensity because the aperture is in the range of dozens of microns to dozens of microns, the present invention places the light-emitting diode on top of the pinhole lens array or on the side of the elastomer, or makes the illumination optical fiber into a mesh and places it on top of the pinhole lens array, which can improve the illumination intensity and reduce the thickness of the entire structure.

Claims

1. A sensing device, comprising: A photosensitive sensor; A pinhole array structure located on the photosensitive sensor; An elastomer layer located on a side of the pinhole array structure away from the photosensitive sensor; A reflective layer located on a side of the elastomer layer away from the pinhole array structure; A light source located between the reflective layer and the pinhole array structure, wherein the pinhole array structure includes a substrate and a plurality of holes spaced apart from each other in the substrate.

2. The sensing device according to claim 1, wherein The shape of the holes includes circular, rectangular, triangular or pentagonal shapes.

3. The sensing device according to claim 1, wherein The light source includes a light-emitting diode or a light-emitting fiber.

4. The sensing device according to claim 3, wherein, The light source includes a group of lighting modules adhesively attached adjacent to the periphery of each hole, or the light-emitting fiber is distributed in a mesh structure between the holes.

5. The sensing device according to claim 1, further comprising a marker located on a side of the elastomer layer away from the pinhole array structure.

6. The sensing device according to claim 5, wherein, The marker is a color block in the form of a grid, hexagon or triangular pattern, arranged in an array or irregularly distributed. The deformation of the elastomer caused by contact with an external entity causes the marker to change its position relative to the photosensitive sensor, so that the photosensitive sensor detects the displacement of the marker.

7. The sensing device according to claim 1, further comprising a transparent rigid layer located between the elastomer layer and the pinhole array structure.

8. The sensing device according to claim 1, further comprising a first transparent protective layer located on one side of the reflective layer.

9. The sensing device according to claim 8, further comprising a second transparent protective layer located on the other side of the reflective layer relative to the first transparent protective layer.

10. A tactile sensing device, comprising: A complementary metal oxide semiconductor sensor; At least one group of pinhole array structures located on the complementary metal oxide semiconductor sensor; An elastomer layer located on a side of the pinhole array structure away from the complementary metal oxide semiconductor sensor; A reflective layer located on a side of the elastomer layer away from the pinhole array structure; A light source located between the reflective layer and the pinhole array structure, wherein the pinhole array structure includes a substrate and a plurality of holes spaced apart from each other in the substrate.

11. The tactile sensing device according to claim 10, wherein, The holes include round holes arranged in a grid and supporting square holes facing a side of the substrate away from the round holes.

12. The tactile sensing device according to claim 11, further comprising a wall between adjacent support square holes in the substrate, wherein, The walls are used to prevent light entering the square holes from entering adjacent square holes covering the photosensitive area groups.

13. The tactile sensing device according to claim 10, wherein, The movement of the marker received on the elastomer layer is recorded by the complementary metal oxide semiconductor sensor and processed to determine the deformation. Wherein, by collecting pictures of the elastomer layer during different force-induced deformations, adding the correction of a standard force sensor, and deriving a force distribution map through an algorithm model based on the deformation, or calculating the force distribution map through the known Young's modulus of the elastomer layer.

14. The tactile sensing device according to claim 13, wherein, The movement is cross-referenced with the information received from the current capture position of the marker and a static image of the captured entity without depression to determine the deformation distribution of the surface to which the complementary metal oxide semiconductor sensor is attached, or Obtain the deformation information in the vertical direction from adjacent or different array hole fields of view, and obtain a three-dimensional force distribution map to determine the deformation distribution of the surface to which the complementary metal oxide semiconductor sensor is attached.

15. A method for manufacturing a tactile sensor, comprising: Providing a pinhole array structure on a monolithic photosensitive sensor, the pinhole array structure including a substrate and a plurality of holes spaced apart from each other in the substrate; Providing an elastomer layer on the pinhole array structure, wherein the elastomer layer includes markers on the surface of the elastomer layer; Providing a reflective layer on a side of the elastomer layer away from the pinhole array structure; and Providing a light source between the reflective layer and the pinhole array structure.

16. The method according to claim 15, wherein, The holes include light channels.

17. The method according to claim 15, wherein, The markers form a contrast with the reflective layer.

18. The method according to claim 15, wherein, The markers are distributed according to a pattern.

19. The method according to claim 15, wherein, The pinhole array structure includes a first surface etched into a circular hole array and a second surface etched into a square hole array.

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