Claims:1. An apparatus for detecting a touch position, the apparatus comprising:
a light source configured to emit a light beam;
a waveguide having a first side wall and a second side wall opposite to the first side wall, each side wall being configured at an inclined angle between an upper surface and a lower surface parallel to the upper surface, the waveguide being operatively coupled with the light source such that the light beam from the light source propagates from the first side wall to the second side wall through getting reflected from the upper surface and the lower surface;
a touching element configured with the upper surface of the waveguide, wherein upon exertion of force, the touching element being configured to move from an upper position in which the touching element is positioned at predetermined distance from the upper surface of the waveguide to a lowered position in which the touching element touches the upper surface of the waveguide, wherein the movement of the touching element into lowered position provides a path for the light beam to move from the waveguide to the touching element, which results in loss of intensity of light beam at the second side wall; and
one or more detectors configured with the waveguide and to detect the light beam propagated though the waveguide.

2. The apparatus as claimed in claim 1, wherein the apparatus comprises a control circuitry configured with the detector, and wherein the control circuitry includes one or more processors and a memory storing instructions which, when executed by one or more processors cause the apparatus to:
receive the detected light beam from the detector;
determine an intensity of the detected light beam;
determine whether the intensity of the light is less than a predefined threshold; and
detect a touch position upon determination that the intensity of the light beam is less than the predefined threshold.

3. The apparatus as claimed in claim 2, wherein the control circuitry is configured to determine an amount of load value on the touch position based on a difference between the intensity of the light bean and the predefined threshold.

4. The apparatus as claimed in claim 1, wherein the touching element and a waveguide are associated with the same refractive index.

5. The apparatus as claimed in claim 1, wherein the inclined angle is dependent on a refractive index of the touching element and waveguide.

6. The apparatus as claimed in claim 1, wherein the light source includes one or more light emitting sources, each being associated with a particular wavelength, wherein the one or more light emitting sources with different wavelengths allow reduction of interference among the detectors that are positioned closed to each other.

7. The apparatus as claimed in claim 1, wherein a refractive index of the touching element and waveguide is greater than a refractive index of surroundings.

8. The apparatus as claimed in claim 1, wherein an angle between the light beam and the upper surface lies between a first predefined angle and a second predefined angle.

9. The apparatus as claimed in claim 1, wherein the first side wall is double pitched wall including two surfaces connected at a middle of the wall, and wherein each the two surfaces of the first side wall is associated with a corresponding slope.

10. The apparatus as claimed in claim 1, wherein the touching element is configured with the upper surface though one or more vertical members to provide support to the touching element for positioning with the upper surface.
, Description:FIELD OF THE INVENTION
[0001] The present disclosure relates to detection of a touch position. More particularly, the present disclosure relates to an apparatus for detecting a touch position and corresponding load value over a surface based on principle of total internal reflection.

BACKGROUND OF THE INVENTION
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0003] Touch pads in recent time are getting much attention due to the diversified technologies including the social interactive robots, internet of ‘action’ (IoA), health-monitoring technologies, prosthetics and augmented reality and so on. With either a touch screen/ touch pad or a pen-based screen, a user may input data by touching the display screen with either a finger or an input device such as a stylus or pen. Thus, in the field of social interactive robotics, the touch pad is an important element for smooth interaction between robot and human. Despite an ample industrial application of robots, huge challenges remain in the field of human interactive robots. Although there are many challenges such as limitation of emotional intelligence, slow response time, consumption of ample amount of power, etc., however, enabling the robots with touch pads having soft sensitive and robust large areas is also one of the most challenging tasks, which needs focused attention.
[0004] Therefore, in recent times, a humongous amount of interest has been observed in the field of soft robotics, and/or biologically inspired soft robotics with large area touch pads. In some cases, the touch pads consisting of multilayered microchannel filled with conducting liquid may be used. The conventional touch pads work based on detection of multiaxis strains and contact pressure. Despite a linear and reproducible strain sensing, a significant hysteresis in pressure sensing has been observed in their sensor. Moreover, there is always a chance of leaking the conducting liquid from the channel in the course of multiple use in real-world environment. In other cases, the touch pads were based on organic field effect transistors (OFETs) made up of a pressure-sensitive elastomer (Ecoflex). However, the process of making these devices are meticulous and complex.
[0005] There is, therefore, a need of an improved apparatus in the art, which overcomes above-mentioned and other limitations of existing approaches.
[0006] All publications herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.

OBJECTS OF THE INVENTION
[0007] Some of the objects of the present disclosure, which at least one embodiment herein satisfies are as listed herein below.
[0008] It is an object of the present disclosure is to provide an apparatus having a soft polymer, capable of sensing strain, touch, and load augmented for real-life application.
[0009] It is an object of the present disclosure is to provide an apparatus for detecting a touch position and corresponding load value over a surface.
[0010] It is an object of the present disclosure is to provide an apparatus including two or more layers separated by an array of vertical members such as micropillars and so on.
[0011] It is an object of the present disclosure is to provide three dimensional (3D) printable apparatus suitable for large scale production.
[0012] It is an object of the present disclosure to provide a system that is economical and reliable.
SUMMARY
[0013] The present disclosure relates to detection of a touch position. More particularly, the present disclosure relates to an apparatus for detecting a touch position and corresponding load value based on total internal reflection.
[0014] The present disclosure provides a simple, cost-effective, practical and robust apparatus for determining a touch position and a corresponding load value. When the touching element is in touch on the waveguide surface, light passes through the contact area due to the identical refractive index of them. The exerted pressure can be calibrated by measuring loss of light at the output. The load on the touching element is proportional to the loss of power of the light intensity. The apparatus can detect touch, strain and pressure with negligible hysteresis.
[0015] The apparatus is capable of interfacing with computer-generated graphical user interface (GUI) through a combination of hardware components based on a set of instructions.
[0016] An aspect of the present disclosure pertains to apparatus for detecting a touch position and corresponding load value. The apparatus may include a light source configured to emit a light beam; a waveguide having a first side wall and a second side wall opposite to the first side wall, each side wall being configured at an inclined angle between an upper surface and a lower surface parallel to the upper surface, the waveguide being operatively coupled with the light source such that the light beam from the light source propagates from the first side wall to the second side wall through getting reflected from the upper surface and the lower surface; a touching element configured with the upper surface of the waveguide, wherein upon exertion of force, the touching element being configured to move from an upper position in which the touching element is positioned at predetermined distance from the upper surface of the waveguide to a lowered position in which the touching element touches the upper surface of the waveguide, wherein the movement of the touching element into lowered position provides a path for the light beam to move from the waveguide to the touching element, which results in loss of intensity of light beam at the second side wall; and a detector configured with the waveguide and to detect the light beam from the waveguide.
[0017] According to an embodiment, the apparatus may include a control circuitry configured with the detector, and wherein the control circuitry includes one or more processors and a memory storing instructions which, when executed by one or more processors cause the apparatus to: receive the detected light beam from the detector; determine an intensity of the detected light beam; determine whether the intensity of the light is less than a predefined threshold; and detect a touch position upon determination that the intensity of the light beam is less than the predefined threshold.
[0018] According to an embodiment, the control circuitry may include configured to determine an amount of load value on the touch position based on a difference between the intensity of the light bean and the predefined threshold.
[0019] According to an embodiment, the touching element and a waveguide may be associated with the same refractive index.
[0020] According to an embodiment, the inclined angle may be dependent on a refractive index of the touching element and waveguide.
[0021] According to an embodiment, the light source may include one or more light emitting sources, each being associated with a particular wavelength.
[0022] According to an embodiment, a refractive index of the touching element and waveguide may be greater than surroundings.
[0023] According to an embodiment, an angle between the light beam and the upper surface may lie between a first predefined angle and a second predefined angle.
[0024] According to an embodiment, the first side wall may be a double pitched wall including two surfaces connected at the middle of the wall, where each the two surfaces of the first side wall is associated with a corresponding slope.
[0025] According to an embodiment, the touching element may be configured with the upper surface though one or more vertical members to provide support to the touching elements for positioning with the upper surface. Additionally or alternatively, one or more other touching elements may also be configured with the lower surface through another one or more vertical members for positioning the lower surface.
[0026] Various objects, features, aspects and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.

BRIEF DESCRIPTION OF THE DRAWINGS
[0027] The accompanying drawings are included to provide a further understanding of the present disclosure and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.
[0028] FIGs. 1A and 1B illustrate exemplary representations of an apparatus of detecting touch position, in accordance with embodiments of the present disclosure.
[0029] FIGs. 2A and 2B illustrate exemplary representation of the apparatus in upper position and lowered position, respectively, in accordance with embodiments of the present disclosure.
[0030] FIGs. 3A and 3B illustrate various views of three-dimensional schematic diagram of the proposed apparatus, in accordance with embodiments of the present disclosure.
[0031] FIGs. 4A-4C illustrate exemplary representations of construction of the proposed apparatus, in accordance with embodiments of the present disclosure.
[0032] FIG. 5 illustrates an exemplary representation of the proposed apparatus in two dimensional model, in accordance with embodiments of the present disclosure.
[0033] FIG. 6 illustrates an exemplary representation of the touching element formed with multiple materials, in accordance with embodiments of the present disclosure.
[0034] FIG. 7A illustrates an exemplary representation of the propagation of light beams inside the single-sloped waveguide, in accordance with embodiments of the present disclosure.
[0035] FIGs. 7B-7D illustrate exemplary representations of the propagation of light beams inside the dual-sloped waveguide or dove prism waveguide, in accordance with embodiments of the present disclosure.

DETAILED DESCRIPTION
[0036] In the following description, numerous specific details are set forth in order to provide a thorough understanding of embodiments of the present invention. It will be apparent to one skilled in the art that embodiments of the present invention may be practiced without some of these specific details.
[0037] Exemplary embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. These embodiments are provided so that this disclosure will be thorough and complete and will fully convey the scope of the invention to those of ordinary skill in the art. Moreover, all statements herein reciting embodiments of the invention, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currently known equivalents as well as equivalents developed in the future (i.e., any elements developed that perform the same function, regardless of structure).
[0038] Embodiments herein relate to an apparatus for detecting a touch position and corresponding load value based on principle of total internal reflection (TIR). The apparatus includes a waveguide configured between a light source and a detector. The waveguide propagates light beams obtained from the light source and directs towards the detector. The waveguide is operatively coupled with a touching element, where the touching element is configured to move from a first position to a second position when a force is exerted on the touching element. The first position corresponds to a position where the touching element is positioned at a predetermined distance from an upper surface of the waveguide. The second position corresponds to a position where the touching element touches the upper surface of the waveguide. When the touching element is in second position, a path is formed between the waveguide and touching element to propagate the light beam from the waveguide and the touching element. It would result in loss of the intensity of light beam at the detector. Based on the loss of the intensity detected by the detector, touch position can be determined. A load value is defined as pressure applied over the touch position. The load value corresponding to the load position may be determined based on the amount of the loss of the intensity of light beam.
[0039] FIGs. 1A and 1B illustrate exemplary representations of an apparatus of detecting touch position, in accordance with embodiments of the present disclosure. As illustrated in FIG. 1A, the apparatus 100 may include a light source 101, a waveguide 102, a detector 103, and a touching element 104.
[0040] In an embodiment, the light source 101 may be configured to emit a light beam towards the waveguide. The light source 101 may include one or more light emitting sources such as light emitting diodes (LEDs), laser diodes and so on, to emit the light beam towards the waveguide. In an embodiment, the one or more LEDs may be arranged in a row such that the light beam is directed towards the waveguide. In an exemplary embodiment, in case of rectangular waveguide, two rows of LEDs may be arranged to form two adjacent sides of a rectangle. Each of the two rows emits the light beam perpendicular to each other. In an embodiment, a collimating lens is provided with each of the one or more light emitting sources for collimating the light into one direction. In this manner, narrow and intensified beam may be generated. In an exemplary embodiment, the light source may be configured to emit the light beam in various colours using absorptive filters, which results in minimization of interference of the light among the sensors.
[0041] In an embodiment, the waveguide 102 may be configured to propagate the light beam from the light source 101 to the detector 103. The waveguide may include a first side wall 102-1 and a second side wall 102-2 opposite to the first side wall. Each of first side wall and second side wall being configured at an inclined angle between an upper surface 102-3 and a lower surface 102-4 parallel to the upper surface 102-3. In an exemplary embodiment, the waveguide may be, by way of example but not limited to, rectangular in shape having edges with the slope of 45 degree. The touching element acts as a sensor unit which senses touch and load value at point of contact or area of contact.
[0042] In an embodiment, the inclined first side wall allows the light beam coming from the light source to direct towards the upper surface, whereas the inclined second side wall allows the light beam to direct towards the detector 103.
[0043] In an embodiment, the waveguide 102 may be operatively coupled with the light source 101 such that the light beam from the light source 101 propagates from the first side wall to the second side wall through getting reflected from the upper surface and the lower surface.
[0044] In an embodiment, the touching element 104 may be configured with the upper surface of the waveguide. Upon exertion of force, the touching element 104 may be configured to move from an upper position in which the touching element is positioned at predetermined distance from the upper surface of the waveguide to a lowered position in which the touching element touches the upper surface of the waveguide. The touching element may be positioned with the waveguide through one or more vertical members 105 such as but not limited to micropillars configured between the upper surface of the waveguide and a layer containing one or more touching elements 104. In an exemplary embodiment, the touching element 104 may be hemispherical in shape, however, it would be appreciated by a person skilled in the art that the touching element may have any shape.
[0045] As shown in FIG. 1A, the touching element 104 is configured with the upper surface of the waveguide. Additionally or alternatively, the touching element may also be configured at the lower surface 102-4.
[0046] The movement of the touching element from the upper position to lowered position provides a path for the light beam to propagate from the waveguide to the touching element, which results in the loss of intensity of light beam at the second side wall. The touching element and the waveguide may be made of the same material. In an embodiment, upper layer of the touching element may be made of soft and transparent/opaque polymer. The waveguide may be made of soft and transparent polymer. When the touching element is in a lowered position i.e. the touching element touches the upper surface of the waveguide, a touching area is formed. The amount of loss of the intensity may depend upon the touching area - with the increase in the touching area, the loss of the intensity increases.
[0047] In an embodiment, the detector 103 may be configured to detect the light beam propagated through the waveguide 102. In an example, the detector 103 may include one or more phototransistors (PTs) arranged with the waveguide opposite to the light source such that the light beam from the light source first passes through the waveguide and then waveguide 102 directs the light beam towards the detector 103. The detector may be operatively coupled with a control circuitry having one or more processors and a memory. In an embodiment, the control circuitry may include microcontroller, microprocessor, and so on to execute the set of instructions stored in the memory. The control circuitry may receive the detected light beam from the detector and then determine an intensity of the detected light beam. The control circuitry may determine whether the intensity of the light is less than a predefined threshold; and detect a touch position upon determination that the intensity of the light beam is less than the predefined threshold. In an exemplary embodiment, determination of the touch position may be based on configuration of light source and detector. In an example, in case of one dimensional configuration where the light source and the detector are arranged in one dimension, one dimensional coordinate may be determined. In another example, in case of two- dimensional configuration (as shown in FIG. 5) where the light source and the detector are arranged in two dimensions, two dimensional coordinates may be determined. In an embodiment, such two dimensional coordinates for the touch position may be determined based on machine learning and artificial intelligence (AI) technique by providing detected intensity at the detector as an input.
[0048] In another embodiment, the control circuitry may determine an amount of load value on the touch position based on a difference between the intensity of the light beam and the predefined threshold. In an embodiment, the difference between the intensity of the light beam and the predefined threshold may be directly proportional to the load value corresponding to the touch position.
[0049] FIGs. 2A and 2B illustrate exemplary representation of the apparatus in upper position and lowered position, respectively, in accordance with embodiments of the present disclosure. As shown in FIG. 2A, when the touching element is not in contact with the waveguide, there is no light beam passing through the touching element, which is based on the principle of total internal reflection (TIR). According to the TIR principle, when the rays of light beam incidents on an incident angle θi greater than a critical angle θc and the refractive index of the waveguide n1 is more than the surrounding n2 e.g. air, the light may get reflected based on principle of the total internal reflection (TIR). Thus, in case when the touching element is not in contact with the waveguide, the refractive index of the waveguide n1 is more than the surroundings n2, therefore the light get reflected according to the TIR principle, whereas in case when the touching element is in contact with the waveguide, the refractive index of the waveguide is equal to the surrounding at the area of contact as the touching element, which is associated with the same refractive index as of the waveguide, becomes surrounding at the area of contact, therefore the light get pass from the waveguide to the touching element. As shown in FIG. 2B, when the touching element is in contact with the waveguide, the loss in the intensity occurs as a portion of the light beam gets transmitted to the touching element from the upper surface of the waveguide.
[0050] FIGs. 3A and 3B illustrate various views of three-dimensional schematic diagram of the proposed apparatus, in accordance with embodiments of the present disclosure. As illustrated in FIGs. 3A and 3B, one or more micro-pillars are configured between a first layer containing one or more touching elements to provide support for the upper surface of the touching element, and a second layer forming the upper surface of the waveguide 102. In an exemplary embodiment, the waveguide and touching elements may be made of Polydimethylsiloxane (PDMS). However, it would be appreciated by a person skilled in the art that the waveguide and touching elements may be made of any material.
[0051] FIGs. 4A-4C illustrate exemplary representations of construction of the proposed apparatus, in accordance with embodiments of the present disclosure. The preparation of proposed apparatus may be divided into three broad categories namely:
1. the array of touching elements e.g., hemispherical lens
2. rectangular waveguide with micropillars and
3. three dimensional (3D )printed holders for sensor and the light sources.
In an example, The making of the array of hemispherical lenses is conducted in two ways i.e. (a) mold-based technique and (b) custom made 3D printing-based technique. The process 401 illustrates the construction of a mold-based array of hemispherical lenses. In an exemplary embodiment, a sheet e.g., Poly(methyl methacrylate) (PMMA) with thickness ~ 5 and area ~150x150 may be modified with an array of holes of numbers with equal separation of 25 among them. The diameter of the holes is ~3 that is precisely achieved by LASER cutting device. Smooth steel balls of diameter ~ 3 are attached on each of the 25 holes in such a way that the half of the balls remain above the smooth surface of the PMMA sheet. The steel balls may be attached to the holes of the PMMA sheet by adhesive e.g. DOWSIL 789 from the back of the holes. These balls work as a hemispherical template for the PDMS HL lens. A 3D printed 3 high square boundary may be attached to the PMMA sheet template and instant UV curable resin is poured on the template. A plain PMMA sheet of same size as of template may cover the template with resin. The UV light source of wavelength 365 nm and power 38 Watt is used for curing the resin for 30 mins as shown in process 403. The cured resin may become solid and is removed from the template that gives array of hemispherical cavities as shown in process 404. The template with hemispherical cavities is used to make the array of hemispherical lenses on a PDMS layer.
[0052] In an exemplary embodiment, the resin template walled by a square of 130 length , 3 hight, and 2 width 3D printed closed wall, PDMS with cross-linking agent (10:1 ratio) is poured on the template and covered by a plain PMMA sheet as shown in FIG. 4A. The PDMS is cured at C for 12 hours, cured PDMS results a layer with an array of PDMS hemispherical lenses with similar dimensions as the templates. The thickness of the film above the hemispherical lenses can be modulated by adjusting the wall height of the 3D printed cage.
[0053] The array of the HL is also made by 3D printing technique through the process 411, 412, 413, 414, and 421 as shown in FIGs. 4B and 4C. A fused deposition modeling (FDM) based 3D printer is modified to print liquid PDMS on a thin PDMS film.
[0054] FIG. 5 illustrates an exemplary representation of the proposed apparatus in two dimensional model, in accordance with embodiments of the present disclosure. As shown in FIG. 5, the light source 101 may include a plurality of light emitting sources 1-10 configured with various color filters 501, where the one or more light emitting sources 1-10 may be arranged in two adjacent rows. The light beam emitted from the light emitting source 1-10 may not follow a straight path rather it spreads due to diffraction of the light beam emitted from the one or more light emitting sources. The detector 103 may be configured with various filters 505 at the opposite sides of the light source. The apparatus may include one or more light diffusers 503 configured to scatter the light beam.
[0055] FIG. 6 illustrates an exemplary representation of the touching element formed with multiple materials, in accordance with embodiments of the present disclosure. As shown in FIG. 6, the touching element 104 may be made of more than one material. The upper part 104B and lower part 104A may be made of two separate materials with different elastic modulus. In an example, the upper part 104 B may have high elastic modulus compared to the lower part 104A. The lower part 104A at low elastic modulus may provide high sensitivity at low load and the upper part at high elastic modulus may allow the apparatus to operate in high load conditions. In an example, the lower part may be made of Ecoflex, whereas the upper part may be made of PDMS material. The lower part 104B may have the same refractive index as of the waveguide.
[0056] FIG. 7A illustrates an exemplary representation of the propagation of light beam inside the single-sloped waveguide, in accordance with embodiments of the present disclosure. The structure of waveguide 102 is crucial in order to achieve better spatial resolution of touching elements. FIG. 7A illustrates a Dove prism shaped waveguide of structure. Due to the refraction or total internal reflection of light (TIR), the rays of light may selectively hit the top surface of the waveguide obeying the basic principle of refraction and TIR of light. In other words, the light beam may reflect from only a region of the upper surface or active region. For proper functioning of the apparatus, the touching element can only be placed on the active region where the light beam gets reflected from the upper surface as shown in FIG. 7A. As a result, the maximum spatial resolution of the touching element of the apparatus is limited by the width of the active region for single Dove prism waveguide structure. In some cases, due to bending or similar effects, the active regions may get shifted. In such cases, the touching element may not be able to sense the touch position. Therefore, eliminating the dark region of the waveguide is essential, where the dark region is defined as regions of the upper surface, which is located between the active regions, and where the light beams do not incident or reflect. In such cases, an angle between the light beam and the upper surface may lie between a first predefined angle and a second predefined angle. In an embodiment, the second predefined angle is dependent on the critical angle, whereas the second predefined angle is defined based on the active regions.
[0057] Additionally or alternatively, a dual sloped waveguide is proposed as shown in FIGs. 7B-7D. In an example, the dual sloped waveguide may have a dual Dove prism waveguide structure with varying slopes. The first side wall 102-1 is a double pitched wall including two surfaces 102-11 and 102-12 connected at the middle of the wall, where each of the two surfaces 102-11 and 102-12 of the first side wall is associated with a corresponding slope. In the dual Dove prism waveguide structure, each of the two surfaces 102-11 and 102-12 of the first side wall has a mirrored symmetric dual side sloped structure, which results in decrease in the width of the dark region and enhance the width of the active region.
[0058] Thus, the present disclosure provides an apparatus for detecting a touch position and corresponding load value over the surface based on total internal reflection (TIR) principle, which is a soft sensitive and have a robust large area.
[0059] While embodiments of the present invention have been illustrated and described, it will be clear that the invention is not limited to these embodiments only. Numerous modifications, changes, variations, substitutions, and equivalents will be apparent to those skilled in the art, without departing from the spirit and scope of the invention, as described in the claim.
[0060] In the foregoing description, numerous details are set forth. It will be apparent, however, to one of ordinary skill in the art having the benefit of this disclosure, that the present disclosure can be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form, rather than in detail, to avoid obscuring the present invention.
[0061] While the foregoing describes various embodiments of the disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof. The disclosure is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the disclosure when combined with information and knowledge available to the person having ordinary skill in the art.

ADVANTAGES OF THE INVENTION
[0062] The present disclosure provides an apparatus having a soft polymer, capable of sensing strain, touch, and load augmented for real-life application.
[0063] The present disclosure provides an apparatus including two or more layers separated by an array of vertical members.
[0064] The present disclosure provides 3D printable apparatus suitable for large scale production.
[0065] The present disclosure provides an apparatus for detecting a touch position and corresponding load value with high sensitivity and quick response time.
[0066] The present disclosure provides a system that is economical and reliable.