U.S. patent application number 10/773760 was filed with the patent office on 2004-09-09 for electronic toothbrush and electronic brush.
Invention is credited to Ikejiri, Takahiro, Nakagawa, Yoshinori.
Application Number | 20040172781 10/773760 |
Document ID | / |
Family ID | 32929561 |
Filed Date | 2004-09-09 |
United States Patent
Application |
20040172781 |
Kind Code |
A1 |
Nakagawa, Yoshinori ; et
al. |
September 9, 2004 |
Electronic toothbrush and electronic brush
Abstract
An electronic toothbrush comprising: a brush head portion having
a bristle portion, to be inserted into an oral cavity, for washing
teeth; and a holder portion to be exposed outside the oral cavity,
wherein TiO.sub.z which is an n-type semiconductor is provided so
as to receive external light; and the n-type semiconductor is
connected to a negative pole of a solar battery and an electrical
potential is superimposed on the n-type semiconductor.
Inventors: |
Nakagawa, Yoshinori;
(Nara-ken, JP) ; Ikejiri, Takahiro; (Osaka,
JP) |
Correspondence
Address: |
FULBRIGHT & JAWORSKI, LLP
666 FIFTH AVE
NEW YORK
NY
10103-3198
US
|
Family ID: |
32929561 |
Appl. No.: |
10/773760 |
Filed: |
February 6, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10773760 |
Feb 6, 2004 |
|
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09738007 |
Dec 15, 2000 |
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Current U.S.
Class: |
15/105 ;
15/167.1; 604/20 |
Current CPC
Class: |
A46B 15/0036 20130101;
A46B 15/0016 20130101; A46B 15/0002 20130101 |
Class at
Publication: |
015/105 ;
015/167.1; 604/020 |
International
Class: |
A46B 009/04 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 17, 2000 |
JP |
2000-215332 |
Claims
What is claimed is:
1. An electronic toothbrush comprising: a brush head portion having
a bristle portion, to be inserted into an oral cavity, for brushing
teeth; a holder portion to be exposed outside the oral cavity; an
n-type semiconductor which is formed of TiO.sub.2 and receives
external light; and a battery which is a solar battery having an
output of more than 0.5 V and less than 3.0 V, connected only to
the n-type semiconductor such that the n-type semiconductor is
connected to a negative pole of the solar battery, and superimposes
an electrical potential on the n-type semiconductor in order to
synergically enhance a photocatalytic effect of the n-type
semiconductor.
2. The electronic toothbrush according to claim 1, wherein the
TiO.sub.2 is an anatase-type crystal.
3. An electronic brush comprising; a brush head portion having a
bristle portion; an n-type semiconductor which is formed of
TiO.sub.2 and receives external light; and a battery which is a
solar battery having an output of more than 0.5 V and less than 3.0
V, connected only to the n-type semiconductor such that the n-type
semiconductor is connected to a negative pole of the solar battery,
and superimposes an electrical potential on the n-type
semiconductor in order to synergically enhance a photocatalytic
effect of the n-type semiconductor.
4. The electronic brush according to claim 3, wherein the TiO.sub.2
is an anatase-type crystal.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an electronic toothbrush
and an electronic brush, and more specifically to an electronic
toothbrush and an electronic brush using a photocatalytic reaction
of an n-type semiconductor.
[0003] 2. Description of the Related Art
[0004] As a method for preventing intraoral diseases such as dental
caries or alveolar pyorrhea, application of a fluoride on the tooth
surface or use of a dentifrice containing a fluoride has been
conventionally practiced in order to further improve the prevention
effect as compared to simply brushing the tooth surface with a
toothbrush bearing a dentifrice adhered thereon. However, questions
remains as to the effect of these methods because an fluorine ion
is inferior in permeability with respect to pulp tissue, and hence,
in order to improve the effect of the fluorine ion, a method has
been suggested that permeability of a fluorine ion is improved by
increasing an electric potential by the action of an external power
supply such as battery, domestic power supply and the like.
[0005] However, also this method is not desirable because it has a
problem that metal ions associated with generation of an electric
current will flow out because a metal which is a conductor is used
for the toothbrush portion, and in addition, the electric current,
electromagnetic waves, or electric fields can have detrimental
effects on a human body when used for a long time.
[0006] In view of the above, the inventors of the present invention
invented an electronic toothbrush utilizing a photocatalytic
reaction of TiO.sub.2 which is an n-type semiconductor, which does
not cause such a problem (Japanese Unexamined Patent Publication
JP-A 58-41549 (SHO-58, 1983). TiO.sub.2 is a compound that
generates a photoelectron voltage even under the irradiation
condition by relatively weak light, and when inserted into the oral
cavity, generates OH radicals from the moisture such as saliva and
elevates the pH in the oral cavity to accomplish neutralization,
thereby decreasing the activity of etiologirc bacteria of dental
caries, as well as decomposing dental plaque.
[0007] However, in the case where only the photocatalytic reaction
of TiO.sub.2 is used, the method of decreasing the activity of
etiologic bacteria.of dental caries having high activity in an
acidic atmosphere will accomplish a predetermined effect as it is,
however it inevitably requires a certain time before it exerts the
effect. In other words, the direct reason of generation of dental
caries is that lactic acid which is generated at the time when the
etiologic bacteria of dental caries ferment saburra attacks hard
tissue of a tooth, and there is a problem that the lactic acid is
continuously generated until the activity of the etiologic bacteria
of dental caries is decreased.
[0008] The inventors of the present invention made a thorough study
for enabling effective decomposition of generated lactic acid, and
found that effective decomposition of lactic acid can be
accomplished by providing an electric potential of more than or
equal to a predetermined value at the time of using the
photocatalytic reaction of then-type semiconductor, and that such
an effect acts not only on decomposition of the lactic acid but
also on decomposition of organic matters.
SUMMARY OF THE INVENTION
[0009] In view of the above problems, it is an object of the
invention to provide an electronic toothbrush which, by using a
photocatalytic reaction of the n-type semiconductor, not only
decreases the activity of etiologic bacteria of dental caries but
also improves decomposition of generated lactic acid, thereby
preventing dental caries more effectively, and to provide an
electronic brush which can wash each part of a body more
effectively than the case where washing is conducted simply by
using soap water, by decomposing organic waste such as dirt
generated at each part of the body.
[0010] The aforementioned object is accomplished by the invention
according to each aspect. That is, an electronic toothbrush
according to the present invention is featured by comprising:
[0011] a brush head portion having a bristle portion, to be
inserted into an oral cavity, for brushing teeth;
[0012] a holder portion to be exposed outside the oral cavity;
[0013] an n-type semiconductor which is formed of TiO.sub.2 and
receives external light; and
[0014] a battery which is a solar battery having an output of more
than 0.5 V and less than3.0V, connected only to the n-type
semiconductor such that the n-type semiconductor is connected to a
negative pole of the solar battery, and supterimposes an electrical
potential on the n-type semiconductor in order to synergically
enhance a photocatalytic effect of the n-type semiconductor.
[0015] According to the present configuration, owing to the
photocatalytic action of the n-type semiconductor, in the case
where the toothbrush is inserted into an oral cavity, in addition
to the fact that OH radicals generated by decomposition of moisture
such as saliva increase the pH within the oral cavity to neutralize
the same, thereby decreasing the activity of etiologic bacteria of
dental caries, the OH radicals reliably and rapidly decompose
lactic acid generated by lactic fermentation of foods by bacteria,
so that dental caries can be prevented from occurring. In other
words, in contrast to the case where only the photocatalytic action
of n-type semiconductor effected by external light is employed
(e.g. fluorescent lamp in a washroom), by superimposing the
electric potential of the battery, an energy level required for
decomposing lactic acid and water can be achieved, so that the
photocatalytic effect of the n-type semiconductor can be improved
synergistically. As a consequence, it is possible to improve the
efficiency of generation of OH radical while reliably improving the
pH by toothbrushing operation. Additionally, in the case of
practically performing toothbrushing operation in a washroom and
the like, even under the condition that light irradiation is weak
because illumination of lighting equipment such as fluorescent lamp
in the washroom is low, since the battery which makes the electric
potential of the n-type semiconductor more than or equal to a
predetermined value is provided, a desired effect can be stably
achieved. As a result, according to the present invention, there
can be provided an electronic toothbrush that can prevent intraoral
diseases such as dental caries more effectively.
[0016] Furthermore, since the n-type semiconductor is formed of
TiO.sub.2 and the output of the battery is more than 0.5 V and less
than 3.0 V, the following effect is brought about.
[0017] Specifically, TiO.sub.2 is effective for improving
decomposition of lactic acid or increasing the pH because it
exhibits a particularly large photocatalytic effect among n-type
semiconductors, and the electrical potential required for causing a
photocatalytic action is maintained more than or equal to the
predetermined value, and the current flowing into a human body via
a hand is kept extremely weak to produce no adverse effect on the
human body, which is advantageous. In other words, when the output
of the battery is less than or equal to 0.5 V, decomposition of
lactic acid is insufficient, whereas when the output of the battery
is more than or equal to 3.0 V, although decomposition of lactic
acid is promoted, the current flowing into a human body is
increased to cause discomfort when the toothbrush is held by a wet
hand, and thus such ranges are not preferable. More preferably, the
output of the battery is not less than 1.0 V and less than 3.0
V.
[0018] In the case where TiO.sub.2issued as the n-type
semiconductor, the reaction formula for decomposing lactic acid
into water and carbon dioxide by photocatalytic action is as
follows: 1
[0019] wherein "p.sup.+" represents a positive hole, "e.sup.-"
represents an electron and "+OH" represents an OH radical.
[0020] Since the present invention employs a solar battery, the
following effects are brought about.
[0021] (a) Since the battery is charged all the time during
toothbrushing with the toothbrush under irradiation of a
fluorescent lamp in a washroom or the like, or in a well-lighted
place where sunlight streams, the photocatalytic action of the
n-type semiconductor is not reduced even as operating time goes on,
so that the effect of the present invention that generation
efficiency of OH radicals is improved to reliably increase the pH
is not reduced at all.
[0022] However, in a primary battery, since a gradual voltage drop
occurs as operating time goes on, the voltage drops over time to
thereby reduce the effect while a user of the toothbrush is not
aware of it. It is true of a secondary battery, which is
rechargeable as in a solar battery.
[0023] (b) The solar battery, being a thin plate-like, can be well
housed along an inner surface of the holder portion even at such a
place as the holder portion of the toothbrush, and the holder
portion does not need to be thickened more than necessary. The
manufacturing cost, therefore, is not increased.
[0024] (c) The service life of a solar battery is generally 20
years or more, which is much longer than a primary battery and
longer than a secondary battery. A user of the toothbrush does not
need change the battery frequently. Unlike a primary battery, the
consumed battery is not frequently disposed.
[0025] (d) The longer service life of a solar battery can hold down
the cost, which is advantageous to a toothbrush which is required
to be supplied at low cost. In a rechargeable secondary battery,
since a battery charger is required and power consumption for
charging is entailed, the cost is higher than that of a solar
battery.
[0026] (e) In a solar battery, unlike a primary battery and a
secondary battery, there occurs no liquid leakage when it is
deteriorated. If liquid leakage occurs, there arises a possibility
that a short circuit between electrodes occurs, thereby causing
heat generation, ignition, disruption or the like. Therefore, it is
not preferable to use a primary battery or a secondary battery for
the toothbrush. Accordingly, in the case of a primary battery, the
battery needs to be removed when not used for a long time, which is
troublesome. A solar battery in which such a possibility never
arises is best suited for toothbrush.
[0027] In addition, according to the present invention, since an
n-type semiconductor is connected to a negative pole of a solar
battery, a remarkable sterilizing effect is brought about.
[0028] It is preferable that the TiO.sub.2 is an anatase-type
crystal.
[0029] The present configuration is effective and advantageous
because such a type of TiO.sub.2 has a particularly large
photocatalytic effect among other types of TiO.sub.2. In this
context, an anatase-type crystal can be easily obtained, for
example, by the method of heating pure Ti to 1200 to 1500.degree.
C. for several minutes in an oxidizing atmosphere.
[0030] Furthermore, an electronic brush according to the present
invention is featured by comprising:
[0031] a brush head portion having a bristle portion;
[0032] an n-type semiconductor which is formed of TiO.sub.2 and
receives external light; and
[0033] a battery which is a solar battery having an output of more
than 0.5 V and less than 3.0 V, connected only to the n-type
semiconductor such that the n-type semiconductor is connected to a
negative pole of the solar battery, and superimposes an electrical
potential on the n-type semiconductor in order to synergically
enhance a photocatalytic effect of the n-type semiconductor.
[0034] According to the present configuration, owing to the
photocatalytic action of the n-type semiconductor, in the case of
washing each part of a body using soap water and the like, OH
radicals generated by decomposition of moisture reliably and
rapidly decompose organic waste such as dirt on the skin surface,
so that higher washing effect can be achieved compared to the case
where only the soap water is used In other words, in contrast to
the case where the photocatalytic action of the n-type
semiconductor is caused by only the external light (e.g.
fluorescent lamp in a bathroom or washroom), by superimposing the
electric potential of the battery, there can be achieved an energy
level required for decomposing organic waste on the skin surface
and water, so that the photocatalytic effect of the n-type
semiconductor can be improved synergistically. As a consequence,
the efficiency of generation of OH radicals can be improved by
scrubbing operation of skin surface- Additionally, in the case of
practically performing washing operation in a bathroom and the
like, even under the condition that light irradiation is weak
because illumination of lighting equipment is low, and even if the
lighting equipment is an incandescent lamp rather than a
fluorescent lamp, since the battery which makes the electric
potential of the n-type semiconductor more than or equal to a
predetermined value is provided, a desired effect can be stably
achieved. As a consequence, according to the present invention,
there can be provided an electronic brush capable of washing each
part of a body more effectively compared to the case where washing
is performed with only soap water.
BRIEF DESCRIPTION OF THE DRAWINGS
[0035] FIG. 1 is a schematic partial section view showing one
embodiment of an electronic toothbrush according to the present
invention;
[0036] FIG. 2 is a section view along the line II-II of FIG. 1
;
[0037] FIG. 3 is a schematic circuit diagram showing an operating
state of the electronic toothbrush according to the present
invention;
[0038] FIG. 4 is a graph showing a sterilizing effect in the ease
where the electronic toothbrush according to the present invention
is used;
[0039] FIG. 5 is a graph showing test results of a lactic acid
decomposition ability of the toothbrush according to the present
invention;
[0040] FIG. 6 is a graph showing test results of decomposition of a
lactic acid solution in relation to varied voltage of the solar
battery according to the present invention;
[0041] FIG. 7 is a schematic partial section view of one embodiment
of an electronic brush according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0042] Embodiments of the present invention are described in detail
with reference to the drawings. FIG. 1 shows a schematic sectional
structure of an electronic toothbrush according to the present
embodiment (hereinafter, also referred to simply as "toothbrush").
This toothbrush 1 comprises a brush head portion 2 in which
bristles 2a are implanted, and a holder portion 3 to be exposed
outside an oral cavity. Preferably, these brush head portion 2 and
the holder portion 3 can be separated from each other. In other
words, when the head portion 2 having the bristles 2a to be
consumed is designed to be replaceable as a consumable item in case
of necessary, in addition to the economical advantage, an advantage
of reducing the size of the waste compared to the case where the
entire toothbrush is disposed is achieved.
[0043] In the holder portion 3, a TiO.sub.2 rod 4 which is an
n-type semiconductor as well as a solar batter 5 of 1.5 V are
incorporated, and a negative pole of this battery 5 and the
TiO.sub.2 rod 4 are connected to each other via a conductive line 6
such as copper wire. At the interface between the brush head
portion 2 and the holder portion 3, there is formed a groove 7 by
reducing the section partly in order to facilitate irradiation of
the external light to the n-type semiconductor. FIG. 3 is a
schematic circuit diagram in an operating state of the electronic
toothbrush using the solar battery 5. In this case, the negative
pole of the solar battery is connected to then-type-semiconductor,
and a voltage is added to a counter pole as a positive pole,
whereby the effect as an optical semiconductor is increased that
much.
[0044] The TiO.sub.2 rod 4 is formed by heating a rod of pure Ti to
1200 to 1500.degree. C. in an oxidizing atmosphere for several
minutes to thereby form a TiO.sub.2 layer on the surface thereof.
TiO.sub.2 of this case is anatase-type crystalline and thus
possesses an especially large photocatalytic capability. And when
the TiO.sub.2 rod 4 receives the external light to give rise to a
photocatalytic reaction, the solar battery 5 increases or maintains
the electric potential of TiO.sub.2 which is an n-type
semiconductor.
EXAMPLES
Example 1
[0045] FIG. 4 shows results of a test in which the effect of the
case where a negative pole of a solar battery was connected to an
n-typed semiconductor was investigated.
[0046] The test conditions are as follows.
[0047] As test bacteria, Streptococcus mutans IFO 13955 which is
considered to be a cause of dental caries was used.
[0048] (i) 4 mL of saline was loaded into a test tube and the test
bacteria were inoculated so that a concentration of the test
bacteria became about 10,000 to 20,000/mL.
[0049] (ii) The solar battery was used and irradiation by a
fluorescent lamp (6 W, at a distance of 10 cm) was conducted at
normal temperatures for 1 to 5 minutes.
[0050] (iii) A viable cell number in 1 mL was measured in a
standard agar medium.
[0051] An initial propagation number of bacteria was
1.3.times.10.sup.4/mL.
[0052] In the accompanying drawing, (A) shows a case where an
n-type semiconductor was connected to a negative pole of a solar
battery (equivalent to the present invention), (B) shows a case
where an n-type semiconductor was connected to a positive pole of a
solar battery, and (C) is blank, showing a case where neither
n-type semiconductor nor solar battery was used.
[0053] In the case of (A), colonies of Streptococcus mutans
decreased rapidly in number for a short time, which shows
remarkable effect was exerted. Since a toothbrushing behavior is
typically performed for a short time, this result shows the
toothbrush according to the present invention has high
practicality.
Example 2
[0054] Furthermore, the effect of a lactic acid decomposition
ability of the toothbrush according to the present invention was
investigated. FIG. 5 shows its test results. This test was
conducted in a method of measuring the pH of a lactic acid solution
with time.
[0055] A lactic acid solution was blended with 0.3 M potassium
sulfate solution and sodium hydrate was further added thereto so as
to adjust the pH to about 5.7. 10 mL of this solution was loaded
into a glass vessel, a structure using sample electrodes (a solar
battery 2.0 V is used. negative pole: TiO.sub.2 electrode, positive
pole: stainless electrode) was inserted into the solution, and the
solution was light-irradiated by a fluorescent lamp of 6 W and
subjected to bubbling with an oxygen gas at 1 L/minute. A distance
between the vessel and the fluorescent lamp was about 3 cm. A
resistor was connected to the sample electrodes to make
predetermined currents (70 .mu.A, 100 .mu.A: equivalent to currents
flowing in a human body at toothbrushing time) flow between the
electrodes. After starting the decomposition, the pH of the lactic
acid solution was measured at intervals of 1 minute in conformity
to JIS K0101 glass electrode method.
[0056] In either case in which the resistor (A-1: 70 .mu.A, A-2:
100 .mu.A) was connected to the sample electrodes, the pH of the
lactic acid solution rose for a shorter time than in a blank case
(C-1: the solution with neither n-type semiconductor nor a solar
battery used)
Example 3
[0057] A decomposition test of a lactic acid solution was conducted
in relation to varied voltage of a solar battery. The results were
shown in FIG. 6. In this test, 50 mL of about 70 ppm lactic acid
liquid was loaded in a flat-bottomed vial (diameter 40.times.height
75 mm) and electrodes of a negative pole made of an n-type
semiconductor with a titanium oxide film formed and a positive pole
made of stainless steel were inserted into the resultant lactic
acid solution to apply a voltage of 0 to 3 V between these
electrodes by a direct current device. The light irradiation was
conducted by a fluorescent lamp of 6 W at a distance of 3 cm, and
the concentration of lactic acid after a lapse of 24 hours was
measured by capillary electrophoresis to investigate the
decomposition of lactic acid.
[0058] FIG. 6 shows the decomposition of lactic acid started under
a load voltage of about 0.5 V and reached saturation at about 2 V.
Accordingly, it is clear that the load voltage of the solar battery
starts to exert a lactic acid decomposion effect at 0.5 V,
remarkable effect at 1 V, and sufficient effect at 2 V.
[0059] (Other Embodiments of the Invention)
[0060] (1) In the above embodiment, although an example of an
electronic toothbrush using TiO.sub.2 which is an n-type
semiconductor has been shown, the TiO.sub.2 which is an n-type
semiconductor can be used for an electronic brush 10 as shown in
FIG. 7. More specifically, in this electronic brush 10, bristles
10a are implanted therein on the front side constituting a brush
head portion, and a holder portion is formed on the rear side, into
which the solar battery 5 is embedded. This solar battery 5 is
embedded in a liquid-tight manner. On the front side where the
bristles 10a are implanted, TiO.sub.2 similar to that shown in the
above embodiment is attached, while a groove 11 which functions as
a water passage is formed in the vicinity of the TiO.sub.2, whereby
communication of soap water and the like is enabled. This groove 11
comprises a penetration hole formed toward base portions of the
bristles 10a, and is configured so that by scrubbing a body with
the bristles 10a, the TiO.sub.2 and the surface of the body are
brought into contact with each other via the moisture, thereby
facilitating decomposition and removal of organic matters such as
dirt existing on the surface by the photocatalytic action of the
TiO.sub.2, and also allowing decomposition of the removed organic
matters. Incidentally, the TiO.sub.2 and a negative pole of the
battery are made conductive via the conductor 6 as shown in FIG. 1.
As the n-type semiconductor, the battery and the conductor, those
similar to those used in the above embodiment can be used.
[0061] As the shape of the present electronic brush, various shapes
other than that shown in FIG. 7 can be employed as long as the
electronic brush is formed into a shape which enables washing by
scrubbing each part of the body with the bristles while the holder
portion being held by a hand. Each part of the body to be washed is
not particularly limited, and hence the present electronic brush
can be used- as a so-called body brush, hair brush, face brush and
the like.
[0062] (2) In the above embodiment, an example in which TiO.sub.2
which is an n-type semiconductor is formed on a Ti rod in layered
shape by heating the Ti rod, however not being limited to the above
configuration, the TiO.sub.2 may be entirely formed by sintering
TiO.sub.2 powder so long as a TiO.sub.2 layer is formed on the
light receiving surface. Also the production method may be such
that the TiO.sub.2 layer is generated on the conductive surface of
a pure Ti rod and the like by the CVD method, PVD method and the
like, and that the TiO.sub.2 layer is generated on the surface by
anodic oxidation of a pure Ti rod.
[0063] (3) For the electronic toothbrush according to the above
embodiment, an example is shown such that the groove 7 is formed at
the interface between the brush head portion 2 and the holder
portion 3 so as to facilitate irradiation of the external light to
TiO.sub.2which is an n-type semiconductor, however, the brush head
portion and the holder portion of the toothbrush maybe formed of a
light-permeable material such as transparent or translucent acrylic
resin, urethane resin, PET resin and the like, thereby providing a
structure without the groove. In addition, when a biodegradable
resin is used as a resin for forming the brush head portion 2,
influence on the environment is diminished even if the brush head
portion 2 is disposed as a consumable item, which is desirable.
* * * * *