In the present invention, the toothbrush head comprises one or more cores, the material of which is transparent to incident and/or emitted radiation, which can guide internally transmitted radiation and has a refractive index N1, the core being surrounded by a sheath which is also Material transparent to incident and/or emitted radiation, the sheath has a refractive index N2, N1 being greater than N2, and therefore internally reflected due to the difference in refractive index between N1 and N2, to direct radiation to the nucleus.
In general, any difference between the refractive index of the core and the surrounding sheath of transparent material will result in internal reflections within the core and thus the desired direction of radiation within the core. Suitable materials from which the core and sheath may be constructed include the transparent plastic materials mentioned above, and these materials may be selected for the core and sheath on the basis of their known differences in refractive index. For example, suitable combinations of cladding and core materials are: Sheath polyamide - polyamide, polymethyl methacrylate, polycarbonate, polyethylene terephthalate or polybutylene terephthalate Alcohol ester core; shell polymethyl methacrylate-core polyamide, polymethyl methacrylate, polycarbonate, polyethylene terephthalate or polybutylene terephthalate; shell poly Carbonate-core polyamide, polymethyl methacrylate, polycarbonate, polyethylene terephthalate or polybutylene terephthalate; polyethylene terephthalate shell core poly Amide, polymethyl methacrylate, polycarbonate, polyethylene terephthalate or polybutylene terephthalate; polybutylene terephthalate shell core polyamide, polymethyl Methyl acrylate, polycarbonate, polyethylene terephthalate or polybutylene terephthalate. As can be seen from this list, polymers that are chemically similar but have different properties, for example to have a different refractive index N2, where N1 is greater than N2, can be used.
An example of such a combination is where the core material is PMMA, typically with an N1 index of ca. 1.7 Combined with PET sheath material, typically N2 has a refractive index of ca. 1.54.
In a preferred construction, the sheath may comprise a monolithic body of transparent material which forms the main structure of the toothbrush head, eg the toothbrush head. The structure to which the bristles are attached. Alternatively, the core and sheath may themselves be enclosed in the toothbrush head, for example by being enclosed in the material making up the structure of the toothbrush head.
Furthermore, the core and/or the head itself may be fully or partially coated with a reflective coating, eg a reflective coating. A thin layer of reflective metal to reflect incident radiation passing in the longitudinal direction of the head onto the bristles.
This reflective layer can constitute a major cause of internal reflections within the core. Thus, in a third embodiment of the invention, the toothbrush head comprises one or more cores made of a material transparent to incident and/or emitted radiation, which can guide the radiation transmitted inside it, the cores being surrounded by a sheath , which is a material that reflects incident and/or emits radiation such that internal reflection occurs within the core in order to direct incident radiation passing along the head in the longitudinal direction to the bristles.
Suitable materials from which the core and sheath may be constructed include the transparent plastic materials mentioned above. Suitable reflective materials include metals, eg thin shiny layers of metals such as aluminum or silver or the like. In the form of an applied layer or sheet applied to the outer surface of the core.
The nuclei described in the preceding embodiments may direct incident radiation or emit radiation, or both incident and emitted radiation. The shape of the cores allows their/their shape to deflect incident and emitted radiation in the manner described above. For example, the surface of the distal core of the cable, or an intermediate surface between the end face of the distal cable core and the cable, may be curved or may be inclined with respect to the longitudinal direction and direction of the cable. bristles so as to reflect, refract or otherwise deflect incident radiation passing in the longitudinal direction of the head towards the bristles.
The core may have a cross-section determined experimentally to be sufficient to transmit a useful intensity of incident and emitted radiation along its length. For example, the core may have any convenient cross-sectional shape, such as circular, oval, rectangular with rounded ends or rounded corners, and the like. Core cross-sectional dimensions can be determined experimentally, but can typically range from 5-95% for convenience, such as 10-50% of the cross-sectional width and/or head thickness.
The core may have a surface substantially perpendicular to the direction of the bristles, so that incident radiation passing along the core may emerge from the core through this surface and thus be directed towards the surface of the tooth. Radiation emitted back from the surface of the tooth can enter the core through the surface and can be directed through the core. For example, the core may be a generally "L" shaped structure with a member oriented generally longitudinally of the head, i.e., perpendicular to the direction of the bristles, and a member oriented in the direction of the bristles. The bristle direction ends in substantially The surface perpendicular to the direction of the bristles. The curvature of the "L" between members may be curved, such as on spherical or chamfered geometries, such as surfaces that present a 45° to members.
The core can extend through the sheath material such that the core is exposed outside the toothbrush head so that radiation can be transmitted directly from the core to the tooth surface and vice versa. Alternatively, radiation entering or exiting the core may need to pass through sheath material or other parts of the toothbrush head on its way to and from the tooth surface.
The transparent plastic material of the toothbrush head described above, such as the body, sheath and core, can be made using known injection molding techniques, which are well known in the toothbrush art. It is important to maintain the clarity of these materials, and if the core and jacket are formed by injection molding, care must be taken to ensure that haze, streaks or air bubbles do not form, etc. This may interfere with the transmission of radiation through the core or sheath.
In a suitable manufacturing process of the inventive cored toothbrush, the core may first be manufactured, for example by injection moulding. The formed core can then be positioned in a second injection molding cavity defining the shape of the sheath, which can be the integral body of the toothbrush head, and the sheath can then mold the second cavity around the core by a second injection molding process. In this last mentioned process, care must be taken that the sheath and core material have the same or similar shrinkage values when cooling after the injection molding process, to ensure that no cracks form due to shrinkage differences.
Accordingly, the present invention also provides an injection molding process in which a toothbrush head or a toothbrush head core is produced, as described above.
Therefore, the present invention also provides an injection mold suitable for this injection molding process.
The reflective metal layer may be in the form of a sheet which may be attached to a pre-formed head or core part during the manufacturing process. For example, if a reflective metal layer is attached to a preformed core and then a header or sheath is formed around it by a subsequent injection molding step, care must be taken to ensure that the metal does not loosen, loosen, or deform the header material during processing. forming. Alternatively, such metal layers may be deposited using other known deposition techniques.
In a preferred embodiment of the invention, the one or more thin radiation-conducting filaments are made of a material transparent to incident and/or emitted radiation, eg . In the wavelength range mentioned above, for example optical fibers can be used to direct radiation from the toothbrush head to the tooth surface and back. Such filaments may typically have a cross-section of about . 0.25 mm. In one form of this embodiment, the one or more toothbrush bristles may include (a) a radiating guide wire, the toothbrush bristles typically having a cross-section of 0.12-0.25mm. Suitable materials from which such filaments can be made are known and include the plastic materials mentioned above. While such filaments may be made of unique materials, such as those commonly used in toothbrush bristles, for radiation guiding functions it is preferred that the filament should comprise a core of material transparent to incident and/or radiation. , that is, the properties of the cladding, core and sheath such that internal reflection occurs within the core to guide radiation along the sheath. For example, the core and sheath of the filament could be a radiation transparent material and the core could have a lower index of refraction than the sheath, similar to the above, so that refraction between the core and sheath internally reflects due to the difference in index of refraction to guide radiation within the core . Suitable combinations of transparent materials for the filament core and sheath are as described above. Methods of making filaments in the form of a core and a sheath are known, eg in WO97/14830 and PCT/EP98/00718, where the core may be a soft elastomer and the sheath may be a harder plastics material. Alternatively, the core of the filament may be transparent and the sheath may be a reflective material, such as a shiny metallic layer, which may be applied by known deposition techniques.
When using one or more filaments (such as bristles) in this way, a good optical connection must be established between the head and the filament. This connection can be made between filaments, such as the material of the headgear, such as the monolithic structural material, or the core inside the head. This can be done in a number of ways.
If radiation directing filaments such as bristles are used in this manner, it is preferred that the ends of the bristles attached to the toothbrush head are attached to the toothbrush head(s) in a manner that allows the radiation to pass through the toothbrush head or core(s) The bristles inside the head and vice versa. For example, the bristles may be attached to the head by a welding process or by being disposed in a bed of liquid hardenable substance so as to form a good optical connection between the head and the bristles. Suitable methods for achieving this are known in the prior art, eg WO 95/31917 and WO 97/39649. During this welding process, the ends of individual bristles or tufts of bristles to be attached to the toothbrush head may be heat fused, forming a "mushroom head" on the toothbrush head. Furthermore, if the mushroom head is formed in this manner, care must be taken that the mushroom head and/or the adjacent ends of the bristles do not become opaque or translucent, but remain transparent to the excitation radiation and/or emitted fluorescence. Some of these known processes, such as the method of WO 97/39649, may allow bristles to be attached to a head having a fixed end with an end face generally perpendicular to the length of the bristles, facilitating light transmission from the head material to the bristles.
Alternatively, the toothbrush bristles may instead be attached to the toothbrush head in a conventional manner whereby many of the bristles are bent in half lengthwise and small metal clips or "anchors" are then secured around the bundle. This is formed and the clip is clamped and inserted into the attachment hole of the toothbrush head. In this case, it may be necessary to cut, polish or sand the curved area in order to create a good optical connection between the head and the bristles.
However, if the bristles of the toothbrush head of the present invention are not used to direct radiation, but only perform the conventional function of cleaning teeth, these bristles can be attached to the head by known techniques without the need for an optical connection to the head.
In a preferred configuration, said light guiding filament is optically connected to said core, eg by being fixed on or in the core. For example, the core may be made of the above-mentioned transparent plastic material, with a surface facing in the direction of the bristles, and the ends of the filaments may be attached to or in this surface. For example, the surface of the core can be configured to closely match the ends of the filaments, and these ends can be bonded into the fiber, eg, physically, in contact with the core surface. Preferably, however, the ends of the bristles are attached to the core by embedding the ends in the core material while in the soft fluid state and allowing the core material to subsequently harden. This can be achieved, for example, by a core made of a plastic material that can be molded into a fluid shape. For example. A thermoplastic and allows the flowable plastic material from the core to flow around the ends of the bristles (while holding them in place) and then solidify. If this is done with a plastic core material in a hot fluid state, the bristle material can also fuse with the core material to form a very tight bond between the bristles and core. Techniques for fusing suitable filaments of toothbrush bristles into thermoplastic materials, such as injection molding, are well known in the art. For example, if the core has the general "L" shape described above, the filaments may be attached to or within the surface substantially perpendicular to the direction of the bristles, eg, perpendicular to the direction of the bristles. Point the end of the "L" shaped core in the direction of the bristles.
Such radiation-guiding filaments may be grouped into clusters, each cluster comprising a plurality of such filaments. One or more clusters can be connected to each core. Such tufts may be circular in cross-section, eg substantially corresponding to the cross-section of the cleaning bristle tufts of a conventional toothbrush, or alternatively the cross-section of the tufts may correspond to the cross-section of a core of non-circular cross-section.
Additionally or alternatively, the toothbrush head may be provided with other radiation guides to direct radiation to and from the tooth surface to the toothbrush head. For example, the bristle surface may be provided with one or more bristle-free regions which act as windows for radiation to pass through and from the tooth surface to the toothbrush head. For example, in addition or alternatively, the toothbrush head may be provided with a lens for transmitting radiation to and from the tooth surface to the toothbrush head, which focuses the radiation emitted from the toothbrush head onto and/or focuses or Radiation emitted from the tooth surface is collected to the aforementioned radiation guide or the aforementioned core.
Materials suitable for such radiation guides, lenses, windows, etc. are transparent materials that are transparent to incident and/or emitted radiation, including known transparent plastic materials such as those mentioned above. If toothbrush bristles are used as radiation conduits, they should be made of a fibrous material sufficiently transparent to the incident and/or emitted radiation of interest.
Suitably on the toothbrush for which the toothbrush head of the present invention is intended, the incident radiation may be of a wavelength known from the above prior art which excites the fluorescence emission of the tooth and/or biological deposits on the tooth surface. No surface deposits objects, and the emitted radiation may be of a wavelength known in the art to correspond to fluorescence emission from these surfaces. Suitably, the incident radiation may have a wavelength between 430 and 500nm and the emitted radiation may have a wavelength above 520nm. Although incident radiation with a wavelength below 430 nm may excite fluorescent emission from biological deposits or tooth surfaces more efficiently than higher wavelength radiation, this lower wavelength radiation may be harmful to oral tissues.
Toothbrushes to which the brushhead of the invention is adapted are also provided with means for generating incident radiation and directing this incident radiation onto the tooth surface. This may include a suitable radiation source, such as a known type of light emitting diode. The means for correlating the emitted radiation to the presence of biological deposits on the teeth may comprise conventional detectors, such as semiconductor photodiodes. A combining filter may be suitable, such as a dichroic mirror, in the optical path between the detector and the test tooth surface to ensure that the detector preferentially receives emitted radiation of the appropriate wavelength. These means, as well as suitable power sources, electronic processing means and means for signaling the presence and/or absence of biological deposits on tooth surfaces may be conveniently located within the handle of the toothbrush. Suitable means for these purposes will be apparent to those skilled in the art and are disclosed in the prior art.
Conveniently, the toothbrush head of the present invention is detachable from the toothbrush handle for which it is intended. This is especially convenient if, as mentioned above, the handle includes a radiation source or the like, so that the head can be replaced when eg its bristles wear out without also replacing these relatively expensive electronic components. If the toothbrush head is detachable from the handle, the joint between the head and the handle must include an optical connector.
On the other hand, the present invention also provides a toothbrush, which has the above-mentioned brush head.
Such a toothbrush may comprise a handle by which the toothbrush may be held, and a head having a bristle surface from which tufts extend in the direction of the bristles, the head and the handle being arranged along a longitudinal axis, providing the toothbrush with a means for radiating and directing the incident radiation to the tooth surface, and having means for collecting radiation emitted from the tooth surface and correlating the emitted radiation with the presence of biological deposits on the tooth,
It is characterized in that the means for directing incident radiation to the tooth surface and/or the means for collecting radiation emitted from the tooth surface comprise a head as described above.
The toothbrush head and toothbrush of the present invention are particularly suitable for or used as the device and method disclosed in GB 9810471.4 and International Application PCT/GB99/03273 filed on May 16, 1998, the contents of which are incorporated herein by reference. Devices used to detect biological deposits on tooth surfaces include:
an illumination device for directing excitation radiation onto the surface of the test tooth,
detection means for detecting fluorescent emissions from remaining tooth surfaces at a wavelength that correlates with that of autofluorescent emissions from tooth surfaces substantially free of biological deposits,
means for comparing the intensity of said fluorescence emission from a test tooth surface with the intensity of autofluorescence emission from a known tooth surface at a wavelength that correlates to the wavelength of autofluorescence emission from a tooth surface substantially free of biodeposition less than biological deposits on the test tooth surface,
means for correlating the comparison thus obtained with the presence of biological deposits on the test tooth surface, and,
Indicating means for indicating to the user of the device the presence of such biological deposits.
The SAR is a value that corresponds to the relative amount of RF energy absorbed in the head of a user of a wireless handset. The FCC limit for public exposure from cellular telephones is an SAR level of 1.6 watts per kilogram (1.6 W/kg).What is the OSHA exposure limit for RF? ›
1910.97, Nonionizing radiation. The exposure limit in this standard (10 mW/sq. cm.) is expressed in voluntary language and has been ruled unenforceable for Federal OSHA enforcement. The standard does specify the design of an RF warning sign.How do I block FM radio signal? ›
Thin amounts of plastic wrap, wax paper, cotton and rubber are not likely to interfere with radio waves. However, aluminum foil, and other electrically conductive metals such as copper, can reflect and absorb the radio waves and consequently interferes with their transmission.What are common sources of exposure to radio wave radiation? ›
The most common sources of radiofrequency radiation are wireless telecommunication devices and equipment, including cell phones, smart meters, and portable wireless devices, such as tablets and laptop computers (1).
Exposure to very high RF intensities can result in heating of biological tissue and an increase in body temperature. Tissue damage in humans could occur during exposure to high RF levels because of the body's inability to cope with or dissipate the excessive heat that could be generated.How much radiation exposure is considered harmful? ›
If doses greater than 1000 mSv occur over a long period they are less likely to have early health effects but they create a definite risk that cancer will develop many years later. Above about 100 mSv, the probability of cancer (rather than the severity of illness) increases with dose.