Patent Application
20160016322
1. Field
The present disclosure generally relates to a cutting instrument. More specifically, the present disclosure relates to a blade having a cutting edge with a cutting angle that varies along a length of the blade.
2. Related Art
Existing blades are often fabricated using metal. However, these existing metal blades are often expensive to fabricate, use processing chemicals that can negatively impact environment and have limited durability or operating life because of cutting-edge degradation (such as micro-chipping and burr formation) and oxidation-induced damage (such as rusting of the blades).
These limitations of existing metal blades often result in difficulties during use, such as skin and tissue irritation, as well as and bleeding, for example, in shaving applications. One approach for improving the overall shaving experience is to include multiple blades in a cutting device, such as a shaver. However, the use of multiple blades increases the complexity and cost of the shaver. In addition, with four or more blades per shaver, this approach has already reached diminishing returns.
Hence, what is needed is a blade without the problems described above.
The described embodiments include a blade. This blade includes a substrate having two surfaces that meet at a cutting edge of the blade, where, at a given location along a length of the cutting edge, the two surfaces are at an angle with respect to one another. Moreover, angles between the two surfaces are different at at least two locations along the length of the blade.
For example, the angles may vary periodically along the length of the blade.
In some embodiments, the blade includes islands having top surfaces positioned at other locations along the length of the blade, where the islands protrude above the cutting edge to protect skin of a user when the blade is used to cut hair. Moreover, the islands may include fluidic channels that provide a fluid at the top surfaces of the islands when the blade is used. For example, the fluid may include a lubricant and/or air.
Furthermore, the blade may include a coating on at least one of the two surfaces configured to prevent fracture of the substrate. This coating may also assist or facilitate the cutting process. Alternatively or additionally, the blade may include another coating on at least one of the two surfaces that indicates a wear status of the blade. For example, the other coating may provide a visible indication when the blade exceeds its operating life, such as a change in the color of the other coating.
Additionally, the substrate may include a monitoring and feedback mechanism (such as anelectronic or an optical monitor) that senses: a presence of moisture and/or a hardness of a material the blade is cutting.
Note that, at the given location, the angle may change from the cutting edge to a base of the substrate that is distal from the cutting edge.
In some embodiments, the angles are associated with one angle category in a set of N potential angle categories for the blade, where N is an integer.
Moreover, the cutting edge may include a cutting pattern along the length of the blade.
Furthermore, a position of the cutting edge may deviate from a plane to define a two-dimensional spatial pattern.
Another embodiment provides a cutting device that includes a handle and the blade. For example, the blade may be rigidly or remateably mechanically coupled to the handle. In some embodiments, the cutting device includes a motor that rotates the blade around an axis of the motor.
Another embodiment provides a method for cutting an object. During this method, a cutting edge of the blade is positioned in at least partial mechanical contact with a surface of the object, where the blade includes the substrate having the two surfaces that meet at the cutting edge of the blade. Moreover, at the given location along the length of the cutting edge, the two surfaces are at the angle with respect to one another, and the angles between the two surfaces are different at at least the two locations along the length of the blade. Then, the blade is displaced along the surface of the object while maintaining the at least partial mechanical contact.
Note that like reference numerals refer to corresponding parts throughout the drawings. Moreover, multiple instances of the same part are designated by a common prefix separated from an instance number by a dash.
Embodiments of a blade, a cutting device that includes the blade, a method for cutting an object, and a technique for fabricating the blade are described. This blade includes a substrate having two surfaces that meet at a cutting edge of the blade. At a given location along a length of the cutting edge, the two surfaces are at an angle with respect to one another. Moreover, angles between the two surfaces are different at at least two locations along the length of the blade. In particular, the angles between the two surfaces may vary along the length of the blade. Furthermore, the blade may include islands having top surfaces positioned at other locations along the length of the blade. These islands may protrude above the cutting edge to protect skin of a user when the blade is used to cut hair. In addition, the islands may include fluidic channels that provide a fluid (such as air or a lubricant) at the top surfaces of the islands when the blade is used.
The blade may be fabricated using semiconductor-process techniques. This may allow the blade to be fabricated on a semiconductor wafer using batch processing techniques (e.g., 20,000 instances of the blade may be fabricated on a wafer prior to singulation). This approach may allow the cost of the blade to be reduced significantly. In addition, the use of semiconductor-process techniques may allow a wide variety of blade structures and/or configurations, which may improve the performance of the blade. For example, the blade may have longer life, or may be less likely to cut or irritate the skin of an individual who uses the blade to shave their hair. In addition, the use of semiconductor-process techniques may improve the reproducibility and reliability of the blade, and may result in a high-yield fabrication process, which may also significantly reduce the cost of the blade.
We now describe embodiments of a blade.
The variation in the angle is further shown in
This capability may also allow blades to be fabricated for different types of applications or, in the case of shaving body hair, individuals having hair with different characteristics. These individuals may be classified into a finite number of classes and suitable blades may be fabricated for each of these classes. Thus, angles 116 may be associated with one angle category in a set of N potential angle categories for blade 100, where N is an integer (such as five).
In some embodiments, blade 100 includes islands 314 having top surfaces 316 positioned at locations 318 along length 312 of blade 100. In particular, except at the ends of blade 100, islands 314 may be positioned between adjacent segments of cutting edge 114. Islands 314 may protrude by a height 308 above cutting edge 114 to protect skin of a user (and, more generally, an object being cut by blade 100) when blade 100 is used to cut hair. Note that islands 314 may prevent the user's skin from contacting cutting edge 114 and, more generally, may reduce friction/stick-slip behavior between blade 100 and the user's skin. Moreover, islands 314 may include fluidic channels 320 that provide a fluid at top surfaces 316 when blade 100 is used. For example, the fluid may include: air, shaving cream, a gel, aftershave, a moisturizer, a disinfectant, a lubricant, a cleaning fluid and/or a pharmacological agent. (Alternatively, at least some of islands 314 may be recessed below the cutting surface to provide fluid.) Furthermore, cutting edge 114 may include an optional cutting pattern 322 along length 312 of blade 100, such as: saw-tooth profile, a plain-tooth profile, an M-tooth profile, a great-American-tooth profile, a champion-tooth profile, a lance-tooth profile, a perforated-lance-tooth profile, or a straight-edge profile.
Referring back to
Additionally, surfaces 112 may be textured to reduce or prevent dust and/or other shaving or cutting products from sticking to blade 100. For example, the texture may enhance a surface roughness of surfaces 112. This texture may also facilitate self-cleaning of blade 100.
Note that, at one of locations 310 (
In some embodiments, substrate 110 includes an optional monitoring mechanism 124 (such as an electronic and/or an optical monitor) that senses: a presence of moisture, a shear force and/or a hardness of a material that blade 100 is cutting. Furthermore, substrate 110 may include optional control logic 126 that is electrically or optically coupled to optional monitoring mechanism 124, and that adjusts the amount of fluid discharged by fluidic channels 320 (
Cutting edge 114 of blade 100 may be along a straight line, i.e., along a dimension. This is shown in
The embodiments of the blade may be used in a wide variety of applications, such as: surgery (e.g., cataract surgery, tissue removal, and/or bone removal), shaving of body hair (or hair removal), preparation of a biological specimen, paint removal, and industrial cutting. For example, one or more instances of the blade may be capable of simultaneously removing multiple layers of a tissue, a material or a specimen.
Note that the applications of the blade may be manual or may include the use of a motor that displaces the blade (such as an electric shaver). This is shown in
We now describe techniques for fabricating the blade. The blade may be fabricated using semiconductor-process techniques on a mother substrate. In particular, the blade may be etched in the substrate (e.g., using isotropic and/or anisotropic etching) and optionally coated with a high hardness material (such as boron nitride). Each instance of the blade may have a high aspect ratio (with a larger height than width) and a sharp edge that can be used for shaving or cutting. The geometry of the blade (as well as the fluidic channels and/or the fluid) may be tailored for a particular user experience. One or more instances of the blade may be transfer printed into an epoxy or a polymer (such as benzocyclobutene) at an arbitrary angle, and then singulated or separated from the mother substrate (e.g., by fracturing the blade from the mother substrate at an etch-defined ‘break’ or fracture point and, more generally, using a release mechanism). The angular position of the one or more instances of the blade may be modified as needed (so that each instance of the blade is positioned at a predefined angle such as 30°), and the polymer with the one or more instances of the blade may be cured (e.g., using ultraviolet light). Sharp edges may be optionally formed on the instances of the blade after singulation (alternatively, the sharp edges may be formed prior to singulation), and the instances of the blade in the polymer may be packaged into a cutting device for subsequent use.
Note that one or more types of impurities or dopants (such as metals, alloys, metal-semiconductors and/or ceramics) may be implanted into the substrate or to the cutting edge(s) to: enhance hardness, reduce brittleness, and/or increase flexibility of the cutting edges. In conjunction with the flexibility provided by the aforementioned fabrication technique, the cutting angle, cutting-edge profile, blade size, sharpness and/or physical properties of the blade may be tailored to optimize the shaving or cutting experience. Thus, the blade may be designed to reduce or eliminate bleeding and skin irritation, or the sharpness reduction that can occur with use. Because the blade may not be subject to oxidation (e.g., it may not rust), it may be more durable than existing metal blades, and may have a longer shelf or use life.
In an exemplary embodiment, the substrate is a <1 0 0> silicon wafer. After an oxide/silicon nitride mask is disposed on a top surface of the silicon wafer, etch pits may be produced by etching using potassium hydroxide. These etch pits may have an angle relative to the top surface of 54.7°. For example, the etch pits may be 213 μm deep and may have a width of 300 μm.
Then, the outer surface of the silicon wafer may be oxidized again, and a photoresist may be spin coated onto one side of the etch pits. This may allow the mask to be etched away from this side of the etch pits.
Next, deep reactive-ion etching (DRIE) may be used to fabricate the high-aspect ratio structures. For example, there may be a series of blades in the shape of walls or ridges every 500 μm. A given blade may have an angled top surface (at an angle of 34.3°), a height of 485-490 μm, and a width of 150 μm (however, the width can range from nanometers to thousands of micrometers). The residual silicon-wafer thickness between the pillars may be 10-15 μm, so the blades can be singulated after being pressed into a polymer (i.e., during the transfer printing). Note that a silicon wafer that is cut and polished at an angle theta (θ) with respect to a <1 0 0>silicon wafer, will produce blades with angled top surface at an angle of (35.3°-θ), thereby offering opportunities for tuning the angle of the cutting edges. Moreover, as noted previously, the blades may have an arbitrary orientation and/or an arbitrary number of blades per package.
The blade may be fabricated using an additive or positive process (i.e., a material-deposition process) and/or a subtractive or negative process (i.e., a material-removal process). For example, the process may include: sputtering, plating, isotropic etching, anisotropic etching, wet etching, dry etching, transfer printing, a photolithographic technique and/or a direct-write technique. Additionally, these processes may utilize a wide variety of materials, including: a semiconductor, metal, glass, sapphire, a ceramic, an organic material (such as plastic, e.g., the blade may be fabricated using injection-molded plastic), a ceramic material, and/or silicon dioxide. Therefore, referring back to
The preceding embodiments may include fewer components or additional components. Although these embodiments are illustrated as having a number of discrete items, these embodiments are intended to be functional descriptions of the various features that may be present rather than structural schematics of the embodiments described herein. Consequently, in these embodiments two or more components may be combined into a single component, and/or a position of one or more components may be changed. While the preceding embodiments illustrated a blade fabricated using photolithographic techniques that has a varying angle (between surfaces 112 in
We now describe embodiments of the method.
In some embodiments of method 700, there are additional or fewer operations. Moreover, the order of the operations may be changed, and/or two or more operations may be combined into a single operation.
In the preceding description, we refer to ‘some embodiments.’ Note that ‘some embodiments’ describes a subset of all of the possible embodiments, but does not always specify the same subset of embodiments.
The foregoing description is intended to enable any person skilled in the art to make and use the disclosure, and is provided in the context of a particular application and its requirements. Moreover, the foregoing descriptions of embodiments of the present disclosure have been presented for purposes of illustration and description only. They are not intended to be exhaustive or to limit the present disclosure to the forms disclosed. Accordingly, many modifications and variations will be apparent to practitioners skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the present disclosure. Additionally, the discussion of the preceding embodiments is not intended to limit the present disclosure. Thus, the present disclosure is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US14/28831 | 3/14/2014 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 61792876 | Mar 2013 | US |
