Patent Application
20200196937
Despite unprecedented advances in nearly all aspects of technology, methods and means of applying dye, coloring or cosmetics to human hair or skin have remained remarkably unchanged in recent decades. Commonly available hair care products generally include a tube of semi-solid dye and a brush or comb-like applicator through which the dye is squirted as pressure is applied to the tube. Another common method of applying hair dye or coloring products is soaking the longer strands of hair in larger volumes of viscous dye while sandwiched between aluminum foil in a technique known as balayage.
Hair coloring products can include harsh chemicals like ammonia, amines or hydrogen peroxide intended to lift up the scaly cuticle layer to expose hair tissue or cortex underneath so that dye pigments are effectively absorbed. Since contact with the underlying scalp or skin is to be avoided, coloring treatment is not able to reach the roots of the hair follicles in the scalp and so often leaving an unattractive residual contrast between the roots and the rest of the dyed hair strands. Further, gray hairs typically are sparsely spread amidst otherwise darker hair with original natural color. Since hair can grow typically a 0.5 inch-1 cm per month, this means that frequent treatments are needed to avoid undesirable contrast between individual gray strands or untreated roots and the treated areas of hair. Also in most cases, to address the individual strands of gray amidst darker surrounding hair requires covering the entire area with color, using far more dye than is needed, and requiring further effort to wash off excess afterward, costing additional time and money. Despite all the effort, the end result is typically unsatisfactory and means that images of not only regular folks but celebrities or politicians can still appear on television or social media with every detail of their imperfectly and incompletely treated hair revealed in high definition.
Prior Art disclosures in this field include: US20100139682 and, ‘Devices and methods for modifying keratinous surfaces’ US20100224205 sensing the existing hair color and then selectively applying dye or coloring in response to the existing variation. Because position encoding or position registration are not included in these previous disclosures they do not address the challenge of controllably delivering the dye ink in proportion to the speed of traversal of the applicator across the uneven length of the hair strands or uneven surface of the scalp. If the volume of dye or cosmetic delivered per unit time is not adjustable according to the change of position per unit time then slowing down of the motion of dye applicator will lead to more dye than is necessary to treat the hair that has been traversed through, and speeding up would result in sparser application of dye. So the prior art does not allow the possibility of a manual application being able to render a controlled or pre-determined pattern by adjusting dose and timing of coloring on to an uneven or fibrous surface such as hair or skin. More recent disclosures include 14,736,551—Rabe et al and 14/736,584, granted as U.S. Pat. No. 9,522,101 and U.S. Pat. No. 10,188,192 in 2016 and 2019 respectively and assigned to Procter & Gamble co. on ‘Cartridges for the deposition of treatment compositions on keratinous surfaces’ describe delivery of cosmetics from a reservoir through nozzles controlled by a microcontroller or CPU after sensing of the skin at down to 10 um2 level; again here there is no position encoder or position registration so does not allow the rendering of a pre-determined pattern onto the skin. Further, none of the published prior art describes schemes to isolate and treat single strands of hair which, like gray hairs, may be in contrast to a different background color.
The hair care products market in the United States is estimated at over $13 billion in 2018, with sales of home-use dyes/coloring products alone accounting for over $2 billion per year. (for example, ‘In Search of the Perfect Hair Dye’—NYTimes March 2018). The dominant trend on hair coloring products is towards using more natural or nature-derived ingredients to coat, not lift up, the hair cuticle layer to achieve the desired end treatment result.
The current invention makes the application of cosmetic treatments to hair, skin as easy as the use of a (computer) mouse. By lifting and drawing hair from the roots into a comb array—like structure comprising teeth the present invention—a smart cosmetic applicator—is able to present each strand for treatment against an array of sub-millimeter sized nozzles which dispense liquid coloring or cosmetic through micro-mechanical means on to the individual strands, adjusting the timing, volume or dose of dye as needed while dispensing to needed target areas only. This avoids the waste of hair coloring and messiness with having to soak all the hair in color as is the case in current art. This invention includes an X-Y position indicator as a means of encoding and measuring rate of change of position of the applicator along the hair strands. This ability to register and measure rate of position or speed of traversal along the hair strands allows calibration and real-time adjustment of coloring dosage to be delivered to the nozzles: slow or fast delivery rate for slow or fast speed of traversal, respectively. Further, sensors may be included in the invention to measure the preceding variation in color or contrast on each individual strand at the leading edge of the applicator so as to adjust the subsequent delivery of coloring or cosmetic as necessary. The data stream from the these initial color state sensors and the position encoders is processed by a microcontroller or central processing unit CPU in order to send the appropriate output controlling electrical signals to the individual nozzles delivering liquid cosmetic. The delivery of artificial coloring or cosmetic to individual hair strands is thus controlled not only by the difference between the pre-existing and the pre-determined target color of the hair but also by the speed of traversal of the applicator across the scalp along the length of the hair strands.
Since the comb like structure comprises teeth that can be similar to that found in common hair or beard trimmers it can reach down to the roots in the scalp to lift the hair slightly to color it down to these roots. The use of sub-millimeter sized nozzles allows the dispensing of cosmetic down to the hair follicles, while avoiding any exposure to the human scalp.
This avoids the disadvantages of the current art of wasting dye on unneeded areas of the hair which require no treatment while providing the advantage of controlled and targeted delivery of cosmetic along individual hair strands to their roots, with dose calibrated and timed by speed of traversal of the applicator, to render a pre-determined pattern of coloring or cosmetic on to hair. With the comb excluded an alternate embodiment of the invention may be used to produce a pre-determined pattern on skin, such as to render a tattoo or body art. An alternate embodiment of the invention may also be used to produce a finely detailed pattern on other keratinous surfaces such as finger or toe nails.
Figures provide explanatory details referenced in the following detailed description. Embodiments depicted in the drawings are illustrative but do not limit the scope of the invention as will be evident to those familiar with the art. Reference numbers are provided to indicate correspondence between reference elements.
The typical human hair is a partially porous fiber made up of strands of the protein keratin and usually less than 100 microns=0.1 millimeter or four thousandths of an inch thick . Since there are typically around 600 hair follicles per square inch of human scalp or about 100 follicles per square centimeter we find that there are typically about 10 hair strands per linear centimeter (or 25 per linear inch) emerging from the typical human scalp. This is, of course, in agreement with common experience: a typical comb, for example, will have teeth spaced according to the typical hair spacing of 10 hairs/cm or 1 mm apart. The gap between adjacent teeth typically narrows or tapers from ˜1-2 mm at the widest end to about 0.1 mm—about the thickness of a hair strand—at its narrowest.
For some perspective on the dimensions involved, our current technological age of microelectronics has enabled billions of smartphones, each with about a billion transistors on silicon chips within them, each such transistor less than 1/1000th of a human hair in width. The 0.1 mm thickness and 1 mm spacing between hair strands is also very wide when compared with the capability of common inkjet or bubblejet printers which print can well over 1000 dots per linear inch (dpi), or one dot per 25 microns=0.025 mm, on to fibrous surfaces such as paper. The cellulose fibers that make up paper are also 10-100 microns thick and the printing process involves absorption of dispensed ink by these fibers. Coincidentally, the average human skin cell is about 30 microns in diameter, with about 1000 fitting in a linear inch.
The technology enabled by a common printer is delivering precise volumes of liquid ink or dye at precise times on to a paper moving past at a constant velocity, resulting in regularly placed ink spots, or dots. The registration of the position of these dots relative to each other enables the rendering of images or text in a precise and repeatable fashion. Inkjet or bubblejet printing has been in common use for over two decades. Inkjet printers for instance use a compact cartridge to dispense ink droplets into ‘dots’ on a page at densities of 100-1200 dots per inch (dpi). This means that the dots can be spaced about 0.02-0.25 mm apart, so that to dye human hair drawn through a comb into a linear array spaced about 1 mm apart the nozzles can be placed even wider than the lowest resolution printers currently available.
Therefore, to enable a smart cosmetic applicator that prints a color pattern onto hair just like a inkjet printer does on paper we would need the following features:
This technology would provide the following advantages over the prior art:
The comb structure that separates the hairs approximately 1 mm apart can be as simple as those seen in common hair trimmers but with the additional feature such that the comb teeth will be at a small, shallow angle to the scalp, and also be tilted slightly from the direction of travel so that linear motion of the applicator achieves the outcome of drawing the hair strands from the roots into the dye stream of the nozzles; the tilt/slant of the comb teeth ensuring that the hairs are lifted up slightly into the proximity of the nozzles that they may receive the dispensed dye droplets reliably.
The sensor array could be a scanner for contrast, such a common barcode scanner, which identifies the pre-existing coloring of the hair for subsequent treatment as needed and also providing to the microprocessor the position of the hairs in the comb array that need dye dispensed on them.
The inkjet nozzle sizes can be chosen to eject dye droplets that are bigger than the width of the widest possible hair (>100 um) so as to wet and coat the entire surface of the hair strand, for effective dye or cosmetic coverage. The dye must wet and diffuse through the ˜5 micron thick outer cuticle to dye the hair cortex which holds moisture and melanin color pigment, underneath. It is important to deliver just the right amount of dye per unit length of hair: neither too much, which would drip off the hair, nor too little, to result in inadequate coloring of the strands. Therefore, it is important to adjust the delivery of dye droplets from the nozzle according to the speed of traversal or rate of travel of the hair through the comb array.
The sensor which detects the prior or initial color of the hair strands may be located at the leading edge of the applicator in the direction of travel so as to feed information to the microcontroller about which hair strands in the linear comb array need treatment from the nozzles that may be located in a section trailing the color or contrast sensor, in the typical direction of motion of the applicator. The position indicator, encoder or linear motion sensor may also be located near the color or contrast sensor at the leading edge of the applicator near where the applicator first meets the hair to be treated. The comb array or structure may also be located so as to have the narrow tip of its teeth towards the leading edge of the applicator so as to lift up the hair strands and draw them into an array for sensing in a regular pattern by the color and linear motion sensors and subsequently towards the individual nozzles in the nozzle array.
The principle behind inkjet printing is well known. A sub-millimeter sized tube draws in liquid ink or dye through capillary action. A pulse of current through a thin-film resistive heating element at one end of the tube causes a vapor bubble to form and this volume expansion causes a droplet of dye or ink to be ejected from the nozzle at the other end of the tube. For the inkjet principle to work the dye needs to include at least one volatile component, a criterion that is easily met by most cosmetics or liquid dyes on the market today. The other micro-mechanical method —the bubble jet—achieves dispensing ink or dye through small nozzles by using a piezo-electric actuator whose vibration produces a liquid stream, which break up into uniformly sized droplets (according to theory first explained by Lord Rayleigh in 1878).
Just with the case of inks used to print on paper, minor modifications to the dye composition, including inert and non-toxic components, may be necessary for optimal dispensing of dye droplets onto hair. As described in Inkjet applications by Matt Gilliland, for example, common inkjet cartridge nozzles are activated by a ˜20V pulse, lasting about 5 microseconds (us) (with about 800 us delay on each nozzle, to allow the nozzles to recharge or refill with dye or liquid ink. There is also typically a 0.5 us delay required before the electronics can trigger or fire another nozzle. The microcontroller may be programmed to trigger such pulses depending on feedback from the various sensors of the applicator—the initial color state sensor and the position encoder. For this purposes of this invention, both the inkjet or bubblejet methods may be used to dispense dye through nozzles according to signals from the microcontroller.
For the position encoder or indicator, we take instruction from the common optical or laser mouse used with computers. Electromechanical or laser optical mice (plural for mouse) have been known since Doug Engelbart's X-Y position indicator for a display system' filed in 1967 (U.S. Pat. No. 3,541,541 granted in 1970) to map the motion on a nearly flat X-Y surface to translate it into, for example, the motion of a cursor on a display for a computer, or in the present case, used to calibrate or adjust the dispensing of dye or liquid cosmetic according to the speed of traversal of the applicator nozzles across the hair strands. (Famously, the mouse was demonstrated at Xerox PARC to Steve Jobs, co-founder of Apple with Steve ‘Woz’niak, who, like Engelbart, had graduated from the University of California, Berkeley)
A typical optical mouse will use the light from a light-emitting diode LED and track relative motion on a surface or substrate by measuring the shift of the reflected light pattern from said surface. A similar principle of specular reflection is used with higher positional accuracy with so-called laser mouse which is capable of position resolution of up to 6000 dot (or pixels) per inch, higher than the more common optical mouse which is generally capable of about 3000 dots per inch (dpi)—this spatial resolution of about 10 microns is adequate to resolve not only individual hair strands but typical human skin cells as well.
Since the typical hair is 4 thousandths of an inch thick, or about 12 dots wide (for an optical mouse; 25 dots wide for a laser mouse) this enables tracking of the traversal rate (speed) and distance traversed and traversal rate (speed) of the relative motion of each hair strand as it passes the comb array.
For the contrast or color sensor commonly available CCD sensors may be used which, coupled with the right color filters may be used to detect not only contrast on a gray-scale but also Red-Green-Blue (RGB) color levels. Such a implementation in common barcode scanners which read an array of dark-light bars used for identification in common shipping or retail applications.
Since both the color sensor and position sensor use common elements such as a source of illumination(an LED or laser) and a method of detecting reflected light off the surface (e.g. a CCD array)—they may be combined into one unit to optimize the design of the applicator. The invention may be modified to include additional functionalities such as LEDs or lasers which provide localized heating of hair strands. Also, localized streams of ions or electrons may be generated to apply electric charge to the hair strands for the purpose of separating the hair strands, as is common in some implementations of inkjet printing.
The length and shape of the comb teeth may be designed to lift hair strands to draw them to the inkjet nozzles to be treated with cosmetic. These may be made retractable so that their length may be adjusted so as to enable the applicator reaching the hair roots, much as a common beard trimmer or electric shaver access hair at their follicles on human scalp or face.
It is noted that the alternate embodiment of the invention may include only the position indicator sensor with the initial color state sensor being optional.
Human skin, like hair, is also made up of dead keratinous cells on its outer surface exposed to the environment. It will be clear to those familiar with the art that, by excluding the comb array unnecessary in this case, the present invention may be used to render a pre-determined pattern of cosmetic, medication or coloring to the uneven, yet locally flat, surface of human skin to produce a tattoo or similar body art. In this case, the spacing of the inkjet or micromechanical nozzles dispensing cosmetic or coloring will tend to be closer depending on the level of detail needed may be comparable to the typical human skin cell at about 30 microns in size, or be spaced at inkjet printer resolution of up to 1000 dots per inch (dpi).
An alternate embodiment of this invention may also be used to produce a finely detailed pattern or image on other keratinous surfaces including human finger or toe nails.
This application claims the benefit of provisional patent application Ser. No. 62/782,300 filed 2018 Dec. 19 by the present inventor. Field of the invention: This invention pertains to the application of dyes, coloring or other cosmetic treatments to generate a controlled pattern on hair, skin or other keratinous surfaces.
| Number | Date | Country | |
|---|---|---|---|
| 62782300 | Dec 2018 | US |
