JP7808837B2 - ultrasonic toothbrush - Google Patents

Description

The present invention relates to electric toothbrushes, and in particular to electric toothbrushes that emit ultrasonic waves.

Electric toothbrushes that vibrate the brush during brushing to improve brushing effectiveness, including plaque removal and cleaning (hereinafter simply referred to as brushing effectiveness), have been put into practical use. Furthermore, ultrasonic toothbrushes that use ultrasound to improve brushing efficiency and achieve better tooth brushing have been proposed, for example, in Patent Documents 1 to 3.

Japanese Patent Application Laid-Open No. 2003-61985 Japanese Patent Application Laid-Open No. 2005-102837 Japanese Patent Application Laid-Open No. 2004-202065

It has been confirmed that ultrasonic toothbrushes provide superior brushing effects unique to ultrasound compared to toothbrushes that do not use ultrasound. However, if the bristles become bent, broken, or worn down during use, the brush section will need to be replaced. Therefore, a design that allows only the brush section to be replaced is desirable.

When an ultrasonic toothbrush has a gap between the vibrating section where the ultrasonic vibrator is located and the bristles, the ultrasonic waves emitted from the vibrating section cannot be transmitted to the brush and cannot be delivered to the surface of the teeth, resulting in an insufficient effect of the ultrasonic waves and an inadequate brushing effect.

However, it is extremely difficult to create a structure that allows the brush part to be replaced without leaving any gaps or air gaps (hereinafter simply referred to as "gaps") between the vibration part and the brush part. Even if the brush part is not replaceable, extremely high dimensional precision is required for both the vibration part and the brush part to prevent even partial gaps between them. For these reasons, there is a demand for an ultrasonic toothbrush that can reliably deliver ultrasonic waves emitted from the vibration part to the tooth surface via the brush, and provide good brushing effects over a long period of time.

In order to solve the above-mentioned problems, the present invention takes the following measures: That is, the toothbrush of the present invention is characterized by having a grip portion, a protruding portion protruding from the tip of the grip portion, a vibration portion formed at the tip of the protruding portion and having a vibrator that generates ultrasonic waves disposed thereon, a bristle portion in which multiple bristle bundles are implanted to form a brush, a brush portion in which the bristle portion is disposed on a first surface and into which the vibration portion is detachably inserted through a first opening, a gap provided between the vibration portion and the bristle portion, a second opening in the first surface that is different from the first opening and leads to the gap, and a third opening in a second surface of the brush portion that is different from the first opening and different from the second opening and leads to the gap .

Furthermore, the ultrasonic toothbrush of the present invention is characterized in that the brush portion has a flow path connecting the gap and the third opening .

The present invention provides an ultrasonic toothbrush that supplies ultrasonic waves to the tip of the toothbrush, achieving a good brushing effect. Furthermore, it is possible to realize a highly reliable ultrasonic toothbrush that can maintain brushing effects over a long period of time with a simpler configuration.

1 is an explanatory diagram of an ultrasonic toothbrush according to the present invention. FIG. 2 is a block diagram of a controller of the ultrasonic toothbrush according to the present invention. FIG. 2 is a schematic diagram of an ultrasonic drive signal according to the present invention. 1 is an explanatory diagram of an ultrasonic toothbrush according to the present invention. FIG. 1 is an explanatory diagram of a conventional ultrasonic toothbrush. 1 is an explanatory diagram of an ultrasonic toothbrush according to the present invention. 1 is an explanatory diagram of an ultrasonic toothbrush according to the present invention. 1 is an explanatory diagram of a charger for an ultrasonic toothbrush according to the present invention. FIG. 1 is a block diagram of a charging circuit for an ultrasonic toothbrush according to the present invention. 3 is a flowchart of charging control of the ultrasonic toothbrush according to the present invention. FIG. 1 is a block diagram of a charging circuit for an ultrasonic toothbrush according to the present invention. 3 is a flowchart of charging control of the ultrasonic toothbrush according to the present invention.

[First embodiment]
FIG. 1 shows the main body 1 of an ultrasonic toothbrush according to the present invention, with (a) to (f) showing six views of the main body 1. (a) is a left side view, (b) is a front view, (c) is a right side view, (d) is a rear view, (e) is a top view, and (f) is a bottom view. (g) shows the main body 1 before the brush unit 13 is attached, and the brush unit 13 has a brush head 14 at its tip. The main body 1 has a grip portion 11, an operating portion 15, and a protruding portion 12 protruding from the tip of the grip portion 11. The protruding portion 12 has a vibrating portion 19 formed at the tip of the protruding portion 12 and having a vibrator 18 that generates ultrasonic waves. The protruding portion 12 and the vibrating portion 19 may be configured as independent components or may be configured as an integrated unit. For example, the vibrating portion 19 having the vibrator 18 that generates ultrasonic waves may be attached to the tip of the protruding portion 12. Alternatively, the protrusion 12 may be elongated to the position where the brush 14 is positioned when the brush part 13 is attached, and a vibrator 18 may be placed at the tip of the protrusion 12 facing or corresponding to the brush 14, thereby forming a vibration part 19 at the tip of the protrusion 12, i.e., the protrusion 12 and the vibration part 19 may be formed as a single unit.

The grip portion 11 contains a battery 16 and a controller 17 that controls the main body 1 in response to the operation of the operation portion 15. The controller 17 and the vibrator 18 are connected by a harness B20, as described below.

The operation unit 15 is equipped with a switch 22, and around the switch 22 is an LED unit 23 that lights up red using a built-in red LED. By pressing the switch 22 on the operation unit 15, the user can control the emitted ultrasound, including emitting or stopping the ultrasound, and the illumination state of the LED unit 23 changes depending on the operation of the switch 22. For example, when the LED unit 23 lights up, the area around the switch 22 lights up red, informing the user of the drive status and operating status of the main unit 1.

Figure 2 is a block diagram of the controller 17. The controller 17 includes at least some or all of a signal generation unit 204 that outputs a drive signal, which is an electrical signal supplied to the vibrator 18 to cause the vibrator 18 to vibrate ultrasonically, a timer 207, a user IF unit 201, a power supply unit 206 that supplies a predetermined amount of power to each unit, and a control unit 202.

The control unit 202 contains a CPU, memory, and an interface for connecting to each unit, and controls the main unit 1. The power supply unit 206 controls the power supplied from the battery 16 to a predetermined constant voltage, for example 5V, and supplies it to each unit via the control unit 202. The user IF unit 201 is connected to the operation unit 15, and when the user operates the operation unit 15, it notifies the control unit 202 of that information.

Battery 16 may be a dry cell battery, or a secondary battery that can be repeatedly used by recharging, such as a lithium-ion battery. Alternatively, instead of these batteries, a power adapter that can output a predetermined voltage, for example, 5V, from a household outlet, such as a 100V outlet, may be placed outside main unit 1. However, secondary batteries may be preferable from the perspective of environmental impact, and this embodiment uses a secondary battery, such as a lithium-ion battery, as an example.

The timer 207 measures a predetermined time, for example, three minutes, as the brushing time, i.e., the time for driving the vibrator 18 to output ultrasonic waves. This time is not limited to three minutes, but can be less than three minutes or more than three minutes, and can be configured so that the user can set it as appropriate.

Figure 3 shows a schematic representation of the output of the signal generation unit 204. In the figure, the horizontal axis represents time and the vertical axis represents signal amplitude. The signal generation unit 204 outputs a signal with a frequency of, for example, 3.2 MHz or 4.8 MHz as a drive signal. In this embodiment, the drive signal outputs, for example, a 4.8 MHz sine wave for time T1, followed by a repeated stop at time T2. If T1 is set to 0.5 seconds and T2 to 0.5 seconds, the drive signal will output 4.8 MHz for 0.5 seconds, then stop for 0.5 seconds, and this cycle will be repeated thereafter. Figure 3 shows the sine wave diagrammatically to make it easier to see, but in reality, as mentioned above, the high frequency of 4.8 MHz is output at T1.

In Figure 3, the drive signal is not output constantly, but is output with a 50% duty cycle as described above, or is output intermittently. There is no significant difference in the ultrasonic effect between constant output and intermittent output as shown in Figure 3, but the actual drive time of the vibrator 18 per unit time is halved, which apparently extends battery life and increases the amount of time you can brush on a single charge. Here, the drive signal is 4.8 MHz output intermittently with a 50% duty cycle, but the duty cycle is not limited to 50% and can be, for example, 40% or 60%, as long as the desired brushing effect is achieved.

When the user presses switch 22, this information is sent to control unit 202 via user IF unit 201, and control unit 202 instructs signal generation unit 204 to output an electrical signal as shown in Figure 3. Alternatively, control unit 202 may be configured to supply power to signal generation unit 204, causing signal generation unit 204 to start generating an electrical signal. Furthermore, control unit 202 notifies timer 207 to start measuring a predetermined time, for example, three minutes, and timer 207 starts measuring the predetermined time in accordance with this notification.

When a predetermined time, for example, three minutes, has elapsed, the timer 207 notifies the control unit 202 of this fact, and based on this notification, the control unit 202 instructs the signal generation unit 204 to stop signal output. Alternatively, the control unit 202 stops the supply of power to the signal generation unit 204, thereby causing the signal generation unit 204 to stop generating a signal.

If the user presses switch 22 again before the specified time has elapsed, this information is notified from user IF unit 201 to control unit 202, and control unit 202 either instructs signal generation unit 204 to stop signal output or stops the supply of power to signal generation unit 204, thereby stopping signal generation by signal generation unit 204. At the same time, it instructs timer 207 to stop measuring time, and resets timer 207.

Regarding the operation of the switch 22 by the user described above, "pressing" the switch 22 does not necessarily mean simply pressing the switch 22. It may also mean pressing the switch 22 twice in a short period of time (a so-called double-click) or holding the switch 22 down for several seconds (a so-called long-press). The operation method may be different for starting and stopping ultrasound output, such as double-clicking to start output and long-pressing to stop signal output. In other words, it is advisable to change the operation method of the switch 22 depending on the purpose of operating the switch 22. This configuration is desirable because it can avoid malfunctions of the device caused by accidentally touching the switch 22. Particularly when the operation unit 15 is located on the grip unit 11, as in this embodiment, the user often touches the operation unit 15 unintentionally. Furthermore, because the user cannot recognize ultrasound, it is difficult for the user to notice that the ultrasound has been unintentionally stopped when the switch 22 is accidentally pressed. This can lead to a situation where the user continues brushing even though the ultrasound has stopped, resulting in the desired brushing effect not being achieved. Therefore, a double-click or long-press, which are actions that are difficult to achieve without the user's intention, are desirable for stopping ultrasound.

Figure 4 shows a brush unit 13 incorporating the present invention. Figure 4(a) is an enlarged view of the brush unit 13, and Figure 4(b) shows a schematic cross-sectional view taken along dashed line A in Figure 4(a). In this embodiment, the brush unit 13 has a brush 14 formed by implanting multiple bristle bundles 45 in a bristle implantation section 43. An opening-A41 is provided in the bristle implantation section 43 at the rear end thereof, in other words, at the proximal end thereof.

Figure 4(c) shows a cross section of the vibration unit 19 inserted into the brush unit 13. At the tip of the vibration unit 19, a vibrator 18 is fixed with adhesive 82 in the portion that corresponds to the brush 14 when the vibration unit 19 is inserted into the brush unit 13. The vibrator 18 is connected to a controller 17 located inside the grip unit 11 by a harness-B20, and a drive signal is supplied to the controller 17. The vibrator 18 may be located inside the vibration unit 19 as shown in Figure 4(c), but it may also be located on the surface of the vibration unit 19, for example, on the surface of the vibration unit 19 facing the brush 14, or on the opposite side of the surface facing the brush 14.

Figure 4(d) shows the state in which the vibration unit 19 in Figure 4(c) is inserted into the insertion portion 44 of the brush unit 13 in Figure 4(b), and the toothbrush body 1 is used for brushing in this state. As shown in the figure, a gap-A42 is formed between the vibration unit 19 and the brush 14. Opening-A41 passes through the bristle portion 43 and connects to gap-A42. When a user uses the body 1, toothpaste, saliva, or moisture such as water containing these (hereinafter collectively referred to as moisture) enters gap-A42 through opening-A41.

As shown in Figure 4, by configuring the brush unit 13 and vibration unit 19 to be detachable, the brush unit 13 can be made replaceable. Note that when the brush unit 13 and vibration unit 19 are replaceable, this detachable configuration is an essential component, as described below. However, in cases where the ultrasonic toothbrush is disposable, for example, the brush unit 13 does not need to be replaced, and so this is not necessarily essential. However, opening-A41 and gap-A42 are essential to ensure that ultrasonic waves are delivered to the teeth reliably.

In toothbrushes that use ultrasonic waves, a part corresponding to the vibration part 19 in Figure 4 is typically inserted into the brush part 13 to facilitate easy replacement. For example, the configuration described in the aforementioned patent document can be represented as shown in Figure 5. In this embodiment, the vibration part 19 is designed to be in close contact with the surface that faces the brush 14, i.e., the ultrasonic wave emitting surface, and the bristle part 43 where the brush 14 is attached, preventing even partial gaps. If a gap were to form, the ultrasonic waves emitted from the vibrator 18 would not pass through the gap, preventing ultrasonic waves from reaching either the brush 14 or the tooth surface, resulting in an inability to achieve the desired brushing effect. To prevent this, the dimensions of the part of the replacement brush part 13 into which the vibration part 19 is inserted must be precisely matched to the dimensions of the vibration part 19 to be inserted. However, due to variations in mass production and changes over time, it is impossible to precisely match the dimensions of the two, making it highly likely that a partial gap will unintentionally form. Furthermore, even if accurate dimensions are used to prevent such gaps from forming initially, gaps may form over time due to, for example, twisting during use. Gaps are also likely to form if the device is dropped, hit against something, or subjected to strong vibrations. When gaps form, ultrasonic waves cannot be delivered to the tooth surface via the brush 14, as described above, and the desired brushing effect cannot be achieved.

On the other hand, in the ultrasonic toothbrush of the present invention, as shown in Figure 4, the bristle part 43 of the brush 14 has an opening-A41, which connects to the gap-A42 formed between the vibrating part 19 and the bristle part 43. Therefore, when moisture flows into the opening-A41, the gap-A42 is filled with moisture. Even though there is a gap-A42, the ultrasonic waves emitted from the vibrating part 19 reach the bristle part 43 due to the moisture that has filled the gap-A42, and are supplied to the tooth surface via the brush 14, achieving the desired brushing effect. The filled moisture is discharged when the brush part 13 is washed after brushing is finished.

In this configuration, the dimensional accuracy of the vibration unit 19 and the insertion unit 44 into which the vibration unit 19 is inserted is sufficient as long as the vibration unit 19 is inserted into the insertion unit 44 and the brush unit 13 is securely attached to the main body 1, so high accuracy is not required, allowing for an inexpensive configuration.

Furthermore, even if changes occur over time in the vibration unit 19 or brush unit 13 during use, or if strong vibrations are applied, such as when the device is dropped, the ultrasonic waves emitted from the vibration unit 19 are reliably supplied to the surface of the teeth being brushed via the moisture that has flowed into gap-A42 and the brush 14, thereby achieving the desired brushing effect.

In other words, by intentionally creating a gap-A42 between the vibrating part 19 and the bristle part 43, which has traditionally been designed to prevent gaps, and filling this gap with moisture generated during brushing through opening-A41, we have achieved an ultrasonic toothbrush with a simpler structure that is resistant to vibration and changes over time without relying on high dimensional precision, can reliably deliver ultrasonic waves to the tooth surface via the brush 14, and provides good brushing results over a long period of time.

The present invention therefore makes it possible to realize a highly reliable ultrasonic toothbrush that will not impair the desired brushing effect over a long period of time, thanks to an inexpensive replacement brush configuration that does not require high dimensional precision and has a very simple structure. Furthermore, even if replacement is not necessary, a highly reliable ultrasonic toothbrush can be realized that will not impair the desired brushing effect over a long period of time, thanks to an inexpensive configuration that does not require high dimensional precision.

[Example of change]
FIG. 6 shows another example of an opening according to the present invention. In FIG. 4, opening-A41 is located at the rear end of the bristle portion 43, whereas in FIG. 6(a), opening-B61 is located at the tip of the bristle portion 43. In FIG. 6(b), opening-C62 is located between the brushes 14. Alternatively, openings may be located on the right or left side of the brush 14 in the axial direction (the direction in which the protruding portion 12 protrudes from the main body 1), such as the right or rear end or the left or front or rear end. Alternatively, these openings may be located at positions corresponding to the side surface, distal end, or proximal end of the gap-A42. For example, FIG. 6(d) shows an example in which opening-H60 is located at the distal end of the gap-A42 or at the tip of the brush portion 13.

While the above description cites an example in which the bristle portion 43 and the brush portion 13 each have one opening, the present invention is not limited to this configuration and may have two or more openings. That is, if opening-A41 is the first opening, a second opening may be provided separately from the first opening. In this case, the openings may have the same size and shape, or may have different shapes and sizes. Note that providing a first opening and a second opening does not mean that there are only two openings, but may also mean that two or more openings are provided. When a first opening and a second opening are provided, moisture in gap-A42 is more easily expelled than when a second opening is not provided. However, because there is an abundance of moisture in the oral cavity during brushing, the moisture is quickly replenished in gap-A42, and the ultrasound is transmitted to the brush 14, preventing a decrease in brushing effectiveness.

While opening-A41 in Figure 4(d), opening-B61 in Figure 6(a), and Figure 6(d) are located at the end of gap-A42, Figure 6(c) shows opening-D63 positioned away from the end of gap-A42. In this case, a pocket 64 surrounded on three sides in Figure 6(c) by the vibration unit 19 and bristle unit 43, etc., is formed at the end of gap-A42. This makes it easy for moisture to accumulate in this pocket 64, and when the brush 14 is washed after brushing and the moisture stored in gap-A42 is drained, drainage may be difficult or insufficient. If drainage is difficult, the moisture in gap-A42 tends to remain in gap-A42, which is undesirable from a hygienic standpoint.

In the present invention, therefore, it is desirable to position openings at the ends of the gap, such as openings-A41, openings-B61, and openings-H-60. Positioning openings at the ends prevents pockets 64, allowing moisture from inside gap-A42 to be efficiently discharged, resulting in a hygienic ultrasonic toothbrush that provides excellent brushing results over a long period of time. Here, "end" does not necessarily refer to the end of gap-A42 corresponding to the front or rear end of the bristle portion 43, as in Figures 4 and 6, but may also refer to the end of gap-A42 corresponding to the right or left side of the brush 14 in the axial direction.

Regardless of whether or not a pocket 64 is provided, if the size or shape of openings such as openings-A41 to openings-H60 (simply referred to as openings) makes it difficult to drain moisture from gap-A42, multiple openings may be provided. For example, two or more openings-A41 may be provided, or two or more openings-B61 may be provided. Alternatively, openings such as openings-A41 and openings-B61 may be used in combination. In this case, the multiple openings may be adjacent to each other, or may be spaced apart, such as at the leading and trailing ends of the bristle portion 43, or on the right and left sides of the bristle portion 43. Alternatively, three or more openings may be provided in three or more regions, such as at the leading and trailing ends of the bristle portion 43 and the right and left sides.

The surface of the brush unit 13 on which the bristle unit 43 is arranged is referred to as the front surface of the brush unit 13 or the first surface of the brush unit 13, and the surface opposite the front surface of the brush unit 13 (first surface of the brush unit 13) is referred to as the back surface of the brush unit 13 or the second surface of the brush unit 13. As shown in Figure 7, one opening may be arranged on the first surface of the brush unit 13 or the front surface of the brush unit 13, and another opening may be arranged on the second surface of the brush unit 13 or the back surface of the brush unit 13. In Figure 7(a), in addition to opening-A41, opening-E65 is also provided on the opposite side of the vibrating unit 19 from the brush 14. In other words, opening-A41, which is the first opening, is provided on the front surface of the brush unit 13, and opening-E65, which is the second opening, is provided on the second surface of the brush unit 13 or the back surface of the brush unit 13. In other words, the first opening is provided on the surface of the brush unit 13 where the bristle unit 43 is arranged, and the second opening is provided on the opposite side of the vibration unit 19 from the bristle unit 43 and the brush 14. Alternatively, opening-A41 and opening-E65 are arranged so that the vibration unit 19 is located between them. Figures 7(b) and 7(c) also show examples in which opening-A41 and opening-F67 or opening-G68 are arranged on either side of the vibration unit 19 or on the front and back surfaces of the brush unit 13. Figure 7(a) shows opening-E65 provided at the tip of the back surface of the brush unit 13 (opposite the brush 14), Figure 7(b) shows opening-F67 provided on the back surface of the brush unit 13 at a position corresponding to the center of the brush 14, and Figure 7(c) shows opening-G68 located on the back surface of the brush unit 13 at a position corresponding to the rear end of the brush 14.

Furthermore, in Figure 7(a), flow path-A66 is provided connecting gap-A42 and opening-E65, i.e., flow path-A66 connects gap-A42 formed between the vibration unit 19 and the brush unit 13 to the second opening, and flow path-A66 allows moisture present in gap-A42 to be easily discharged from opening-E65. Figure 7(d) schematically shows a cross section taken along dashed line B in Figure 7(b). Figure 7(d) shows an example in which flow path-B69 connecting gap-A42 to opening-F67 is provided on both sides of the vibration unit 19, but flow path-B69 may be provided on at least one side of the vibration unit 19, or in Figure 7(d) on at least one of the right and left sides of the vibrator 18.

Figure 7(e) is a schematic cross-section taken along dashed line C in Figure 7(b). In Figure 7(e), flow path-B69 is located at the position of opening-F67 through a recess or groove provided in the brush portion 13. Figure 7(f) shows another example of a flow path, in which flow path-C70 is provided in place of flow path-B69 in Figure 7(e). However, flow path-C70 is formed at the tip of the vibration portion 19, extending along the longitudinal direction of the vibration portion 19. As shown in Figure 7(f), flow path-C70 may have a length equal to the longitudinal length of void-A42, which is desirable because it prevents the formation of a pocket like pocket 64. For flow paths-A66 and flow path-B69, the longitudinal angle of the brush portion 13 must be appropriately adjusted to allow moisture to flow toward the second opening. However, flow path-C70 is more desirable because it allows moisture from void-A42 to be smoothly discharged regardless of the longitudinal angle of the brush portion 13.

Figure 7(c) shows an example in which gap-B46 is formed between the vibration unit 19 and the back surface of the brush unit 13. The surface of the vibration unit 19 facing the front surface of the brush unit 13 is referred to as the front surface of the vibration unit 19, or the first surface of the vibration unit 19, and the surface of the vibration unit 19 facing the back surface of the brush unit 13 is referred to as the back surface of the vibration unit 19, or the second surface of the vibration unit 19. If gap-A42 formed between the front surface of the vibration unit 19 and the brush unit 13 is referred to as the first gap, gap-B46 formed between the back surface of the vibration unit 19 and the brush unit 13 corresponds to the second gap. In other words, Figure 7(c) shows an example in which a first gap and a second gap are arranged, and opening-A41, which is the first opening, and opening-G68, which is the second opening, are connected by flow paths that connect the first gap to the second gap and the first gap to the second gap. In this case, flow path B69 in Figure 7(e), flow path A66 in Figure 7(a), or flow path C70 in Figure 7(f) can be used.

Figures 7(d) to 7(f) show examples in which flow path-B69 and flow path-C70 are provided on all surfaces of the vibration unit 19 except for the front and back surfaces, but flow path-B69 and flow path-C70 may also be provided on at least one surface of the vibration unit 19 other than the front and back surfaces. For example, in Figure 7(d), they may be provided on at least one of the right or left sides of the vibration unit 19, and in Figures 7(e) and 7(f), they may be provided on at least one of the top or bottom sides of the drawing.

In the illustrated example, flow path-A66, flow path-B69, and flow path-C70 are formed by providing recesses or grooves in the brush portion 13, but flow path-A66 may also be formed by providing recesses or grooves in the vibration portion 19, or by providing recesses or grooves in both the brush portion 13 and the vibration portion 19. In other words, they may be formed as recesses or grooves provided on at least one of the inner surface of the brush portion 13 or the surface of the vibration portion 19.

The examples in Figures 7(a) to 7(f) are not limited to these, and instead of opening-A41, opening-B61, opening-C62, opening-D63, or opening-E65 can be used as the first opening. Alternatively, in Figure 7(c), opening-F67 can be used instead of opening-G68, i.e., an opening can be provided near the center of the bristle section 43, or gap-B46 can be added to the configuration of Figure 7(b). Alternatively, the first opening can be located on a side or end surface other than the front or back surface of the brush section 13, or at least one of the first opening and the second opening can be located on a side or end surface.

The above configuration allows for an inexpensive replacement brush with a very simple structure that does not require high dimensional precision, and it is possible to create an ultrasonic toothbrush that is highly reliable and resistant to vibrations without compromising the desired brushing effect over a long period of time.

Figure 8 shows a charger 71 for charging the battery 16 placed inside the main unit 1. Figure 8(a) is a top view of the charger 71, which has a through-hole 73 in the center of a circular holder 72 when viewed from above. The main unit 1 is inserted into the through-hole 73 for charging. Figure 8(b) is a cross-section along the dotted line in Figure 8(a), showing the main unit 1 inserted into the through-hole 73. As shown in Figure 8(b), the charger 71 has a through-hole 73 formed in the center of a low, cylindrical holder 72, penetrating from the top to the bottom of the holder 72. The charger 71 is used by connecting it to, for example, a household wall outlet via a power cord 74. When the main unit 1 is inserted into the through-hole 73 as shown in Figure 8(b), wireless charging of the battery 16 is performed using well-known electromagnetic induction, but detailed explanations of the principles are omitted. The charger 71 is placed on a surface 75, such as a table or bathroom sink, so that the bottom of the main unit 1 contacts the surface 75. With this configuration, even if moisture adhering to the main body 1 or brush part 13 drips onto the plate surface 75, it will not accumulate on the charger 71 and soil it. The main body 1 and charger 71 can be lifted to easily clean the plate surface 75, making it easier and more convenient to keep the main body 1, charger 71, and their surroundings clean.

A power transmission power source 77 is located inside the charger 71, supplying power received via the power cord 74 to the power transmission coil 76. The power is then transmitted contactlessly to the main unit 1 via the power transmission coil 76 via an alternating magnetic field. The main unit 1 also contains a power receiving coil 79 and a charging circuit-A 78, which receive power contactlessly from the power transmission coil 76. The charging circuit-A 78 has a remaining charge detection unit that detects the remaining charge in the battery 16 and a charger detection unit that detects when the main unit 1 is attached to the charger 71, and controls the supply of power received by the power receiving coil 79 to the battery 16. The power transmission coil 76, power transmission power source 77, and the wiring connected to them are located inside the charger 71, while the power receiving coil 79, charging circuit-A 78, and the wiring connected to them are located inside the main unit 1, and are not normally visible from the outside.

Figure 9 shows a block diagram of the charging circuit-A78. The charging circuit-A78 has a rectifier circuit 81 that rectifies the power from the receiving coil 79, and the output of the rectifier circuit 81 is supplied to the battery 16 via the remaining charge detector-A84, which detects the remaining charge, and the switch element 80. The charging control unit-A83 controls the on/off of the switch element 80, thereby controlling the charging of the battery 16. The remaining charge detector-A84 detects the remaining charge of the battery 16 and notifies the charging control unit-A83. The charging control unit-A83 is further connected to a charging timer 85 that measures the charging time.

The remaining charge detection unit-A84 detects the voltage VA generated in the switch element 80 based on the power received by the receiving coil 79 and the current I flowing through the switch element 80, and a signal based on these is sent to the charging control unit-A83. As described below, the signal indicating the voltage VA corresponds to a signal indicating whether the main unit 1 is attached to the charger 71, or a signal indicating whether it is attached or not. The signal indicating the current I corresponds to a signal indicating charging of the battery 16, a signal indicating whether the battery 16 is being charged, or a signal indicating the remaining charge of the battery 16.

Since voltage VA is generated when main unit 1 is placed in charger 71, it is detected whether main unit 1 is placed in charger 71 or whether main unit 1 is placed in through-hole 73, and the signal indicating voltage VA corresponds to a signal indicating that main unit 1 is attached to charger 71. In other words, in this configuration, remaining charge detection unit-A84 also functions as a charger detection unit that detects whether main unit 1 is attached to charger 71.

The voltage VA may be used as a signal indicating that the main unit 1 is attached to the charger 71, but in this embodiment, it may also be compared with a preset threshold Vth1, and the comparison result may be used as a signal indicating that the main unit 1 is attached to the charger 71. For example, the remaining charge detection unit-A84 may compare the voltage VA with the threshold Vth1, and if the voltage VA is equal to or greater than the threshold Vth1, send a signal indicating that the voltage VA is equal to or greater than the threshold Vth1 to the charging control unit-A83 as a signal SG1 indicating whether the main unit 1 is attached to the charger 71. The threshold Vth1 may be set lower than the voltage generated when the main unit 1 is attached to the charger 71.

On the other hand, current I occurs when charging is being performed, and tends to be large when the remaining charge of battery 16 is low and small when the remaining charge of battery 16 is high. Therefore, the remaining charge of battery 16 can be detected by current I, and current I corresponds to a signal indicating the remaining charge of battery 16.

Current I may be used directly as a signal indicating the remaining charge of battery 16, or, as in this embodiment, it may be compared with a preset threshold Ith1, and the comparison result or a signal indicating the comparison result may be used as a signal indicating the remaining charge of battery 16. For example, remaining charge detection unit-A84 compares current I with threshold Ith1, and if current I is less than threshold Ith1, this indicates that battery 16 is sufficiently charged or has a sufficient remaining charge. Therefore, a signal indicating that current I is less than threshold Ith1 may be sent to charging control unit-A83 as signal SG2 indicating the remaining charge of battery 16.

Without being limited to the above embodiment, the signal SG1 indicating whether the main unit 1 is attached to the charger 71 may be information or a signal based on the electromotive force or electromotive voltage generated between the terminals of the receiving coil 79, or a separate sensor such as an optical sensor or Doppler sensor may be provided to determine whether the main unit 1 is attached to the charger 71. Furthermore, the output voltage or output current of the battery 16 may be used as a signal indicating the remaining charge of the battery 16.

When the main unit 1 is inserted into the through-hole 73 of the charger 71, the receiving coil 79 receives power from the transmitting coil 76 and sends it as received power to the switch element 80 via the remaining charge detection unit A84. The switch element 80 is in the on state when the main unit 1 is attached to the charger 71, and the received power is supplied to the battery 16. The remaining charge detection unit A84 measures the voltage VA and compares it with the threshold value Vth1. If the voltage VA is equal to or greater than the threshold value Vth1, it notifies the charging control unit A83 of SG1. When the charging control unit A83 detects the signal SG1, the charging control unit A83 instructs the charging timer 85 to start measuring the charging time. Based on this instruction, the charging timer 85 begins measuring a preset charging time, for example, three hours.

Furthermore, the remaining charge detection unit-A84 measures the current I supplied to the battery 16 via the switch element 80 and compares it with threshold value Ith1. If the current I is less than threshold value Ith1, it sends a signal indicating that the current I is less than threshold value Ith1 as SG2 to the charging control unit-A83. When the charging control unit-A83 detects SG2, SG2 indicates that the remaining charge of the battery 16 is sufficient and charging is not necessary, so the charging control unit-A83 controls the switch element 80 to turn off, cutting off the power supply to the battery 16 and stopping charging, and also instructs the charging timer 85 to stop timing.

Conversely, if SG2 is not detected from the remaining charge detection unit A84, the charging control unit A83 does not control the switch element 80, so the switch element 80 remains on, power continues to be supplied to the battery 16, and charging continues. However, as charging continues, the current I may fall below the threshold Ith1. In this embodiment, if charging continues, the remaining charge detection unit A84 may not send anything to the charging control unit A83. Alternatively, the remaining charge detection unit A84 may send a signal to the charging control unit A83 indicating that charging is necessary or will continue.

When the charging time has elapsed, the charging timer 85 sends a signal indicating that the charging time has elapsed to the charging control unit A83, and based on that notification, the charging control unit A83 controls the switch element 80 to turn off. In this case, the battery 16 may not be fully charged, but always keeping it fully charged is not necessarily desirable for maintaining good performance of the battery 16 over the long term. The charging time should be longer than the time required to charge enough power to achieve the desired brushing when using the main unit 1, and there is no particular problem if the battery is not fully charged.

On the other hand, when the switch element 80 is on, i.e., when charging is in progress, the remaining charge detection unit A84 does not always notify the charging control unit A83 of SG2 even if the current I falls below the threshold Ith1 in this embodiment. That is, SG2 may be notified immediately after SG1 is notified, or within a predetermined time after SG1 is notified. Alternatively, SG2 may be notified to the remaining charge detection unit A84 at any time regardless of SG1, but the charging control unit A83 can also be controlled not to acquire SG1 after a certain time has passed since acquisition, or to ignore or invalidate it if acquired.

The remaining charge detection unit-A84 compares the current I with a preset threshold value Ith2, and when the current I falls below threshold value Ith2, it sends a signal SG3 indicating this to the charging control unit-A83. Threshold value Ith2 is set lower than threshold value Ith1, and the setting is sufficient so that when current I falls below threshold value Ith2, it indicates that the battery 16 is fully charged or nearly fully charged. Therefore, SG3 is a signal indicating that the battery 16 is fully charged or nearly fully charged. When the charging control unit-A83 detects this SG3, it controls the switch element 80 to turn off, cutting off the current supply to the battery 16 and halting charging, and instructs the charging timer 85 to stop measuring time.

Note that although a charging time of 3 hours has been used as an example, it is not limited to this and may be set appropriately depending on the capacity and capabilities of the transmitting coil 76, receiving coil 79, and battery 16, and may be, for example, 1 hour, 5 hours, or 11 hours. Furthermore, although different values are set for threshold value Ith1 and threshold value Ith2, this is not limited to this and the same value may be used for threshold value Ith1 and threshold value Ith2. Furthermore, the comparison of voltage VA with threshold Vth1 and the comparison of current I with threshold Ith1 or threshold Ith2 may be performed in a circuit other than the charging control unit A83, such as the remaining charge detection unit A84, as described above. However, the remaining charge detection unit A84 may send a signal indicating voltage VA or current I to the charging control unit A83 as SG1, SG2, or SG3, and the charging control unit A83 may acquire this signal and compare it with threshold Vth1, threshold Ith1, and other thresholds, and the charging control unit A83 may control the switch element 80, i.e., perform charging control, based on the comparison results.

When the main unit 1 is removed from the charger 71, the receiving coil 79 cannot receive power from the transmitting coil 76, and the voltage VA detected by the remaining charge detection unit A84 falls below the threshold Vth1. The remaining charge detection unit A84 sends a signal SG4 to the charging control unit A83 indicating that the voltage VA has fallen below the threshold Vth1. When the charging control unit A83 detects the signal SG4, it controls the switch element 80 to turn on, preparing for the case in which the main unit 1 is again attached to the through-hole 73 of the charger 71 and charging resumes.

Alternatively, instead of transmitting SG4, the remaining charge detection unit A84 may always or repeatedly transmit SG1 when the voltage VA exceeds the threshold Vth1, but may stop transmitting SG1 to the charging control unit A83 or not transmit SG1 to the charging control unit A83 when the voltage VA falls below the threshold Vth1.

Figure 10 shows an example of the above control in the form of a flowchart. First, in S1, the charging control unit-A83 detects a signal SG1 indicating that the main unit 1 has been attached to the charger 71. In S2, the charging control unit-A83 instructs the charging timer 85 to start measuring the charging time. When the charging control unit-A83 acquires a signal SG2 indicating that the battery 16 has sufficient remaining power (S3), it instructs the charging timer 85 to stop measuring the charging time in S6, turns off the switch element 80 (S6), and stops charging (S7). Even if SG2 is not detected in S3, or if SG3 indicating that the battery 16 is fully charged is detected in S4, S6 is similarly executed and charging is stopped (S7). Even if neither SG2 nor SG3 is detected, when the charging time has elapsed (S5), the switch element 80 is controlled to be turned off (S6), and charging is stopped (S7).

Figure 11 is a block diagram showing an example of a charging circuit-B101 that performs other charging control. In charging circuit-A78, remaining charge detection unit-A84 serves both as a remaining charge detection unit that detects the remaining charge of battery 16 and as a charger detection unit that detects when main unit 1 is attached to charger 71. However, charging circuit-B101 has remaining charge detection unit-B102 as a remaining charge detection unit that detects the remaining charge of battery 16, and charger detection unit-103 as a charger detection unit, both of which are connected to charging control unit-B104.

Similar to the charging circuit-A78, the output of the rectifier circuit 81 is sent to the battery 16 via the switch element 80, etc., to charge the battery 16. The remaining charge detection unit-B102 is connected to the battery 16 and detects the output voltage VB of the battery 16, and sends a signal indicating voltage VB to the charging control unit-B104 as a signal indicating the remaining charge of the battery 16. The charger detection unit 103 is also connected to the switch element 80 and detects voltage VA, and sends a signal indicating voltage VA to the charging control unit-B104. Here, voltage VA corresponds to a signal indicating whether the charger 71 of the main unit 1 is attached or not, or a signal indicating whether it is attached or not, and voltage VB corresponds to a signal indicating charging of the battery 16, or a signal indicating whether charging is occurring, or a signal indicating the remaining charge of the battery 16.

Figure 12 shows an example of a flowchart for charging control in the charging circuit-B101. In the charging circuit-B101, the charging control unit-B104 acquires SG1, a signal indicating the voltage VA notified from the charger detection unit 103 and indicating whether the main unit 1 is attached to the charger 71, and compares the voltage VA with the preset Vth1. If the voltage VA is equal to or greater than Vth1, this indicates that the main unit 1 is attached to the charger 71, and the charging timer 85 is instructed to measure the charging time (S2).

The charging control unit-B104 then acquires the voltage VB and compares it with a preset threshold Vth2 (S3). If the voltage VB exceeds the threshold Vth2, the remaining charge is sufficient, meaning charging is not necessary, and the switch element 80 is turned off, charging timer 85 stops measuring the charging time (S6), and charging is stopped (S7). Conversely, if the voltage VB is below the threshold Vth2, this indicates that charging is necessary, or that the battery is not fully charged or not close to being fully charged, and the switch element 80 is not controlled, but remains on, allowing charging to continue. If VB at full charge is, for example, 4.2V, then the threshold Vth2 value can be 3.7V, but is not limited to this and can be determined appropriately depending on the characteristics of the battery 16 and the specifications of the main unit 1.

As charging continues, if the charging control unit-B104 detects that VB notified by the remaining charge detection unit-B102 has exceeded threshold value Vth3 (S4), VB indicates that the battery 16 is fully charged or nearly fully charged, so the charging control unit-B104 controls switch element 80 to OFF to cut off the power supply to the battery 16, stops timing (S6), and stops charging (S7). Threshold value Vth3 is normally set to a value greater than threshold value Vth2. Threshold value Vth3 may be, for example, VB when the battery 16 is fully charged, but is not limited to this and may be determined appropriately depending on the characteristics of the battery 16 and the specifications of the main unit 1. Furthermore, if the charging time has elapsed (S5), the charging control unit-B104 also controls switch element 80 to OFF (S6) and stops charging (S7), just like the charging circuit-A78.

When the main unit 1 is removed from the charger 71, the charging control unit-B104 detects that the voltage VA obtained from the charger detection unit 103 has fallen below the threshold value Vth1, and the charging control unit-B104 controls the switch element 80 to turn on.

In the above case, the user cannot determine whether charging is taking place. Therefore, for example, a separate LED may be placed on the main unit 1 to indicate that charging is taking place in the battery 16, i.e., when current I is detected, the LED lights up to notify the user that charging is taking place. However, in the above control, when the main unit 1 is inserted into the charger 71 and the current I detected by the remaining charge detection unit A84 falls below threshold Ith1, i.e., if the remaining charge in the battery 16 is sufficient and charging is not necessary, this is immediately notified to the charging control unit A83, which then controls the switch element 80 to OFF, stopping charging and causing current I to no longer be detected or to become zero. In this case, the LED lights up briefly when the main unit 1 is inserted into the charger 71 and then immediately goes out, which could lead the user to mistakenly believe that charging is not taking place properly or that a malfunction has occurred.

The LED may be configured to light after a certain time (e.g., 3 seconds) has elapsed since the detection of current I, or may be configured to light if current I is detected again after the certain time has elapsed. Alternatively, the LED may be configured to light up once upon detection of current I and not turn off for a certain time (e.g., 3 minutes). In this case, the LED will not turn off for the certain time, making it easier for the user to determine that there is nothing abnormal with the charging control, and is desirable as it will not mistakenly lead to the belief that the charger 71 or main unit 1 is faulty.

The LEDs described above may be controlled by the charging control unit-A83 or charging control unit-B104, or a separate circuit may be provided to control the LEDs.

Generally, with batteries, especially secondary batteries such as lithium-ion batteries, keeping them fully charged for long periods of time or all the time is not necessarily desirable, as it reduces capacity, shortens battery life, reduces output, and leads to a decline in battery performance. To avoid this, charging control is implemented to prevent the battery from reaching full charge, for example by calculating the charge amount and charge time. However, this requires circuitry to calculate the charge time and charge amount, as well as circuitry that can control charging based on the calculation results, which leads to an increase in the size and complexity of the charging system. Furthermore, an increase in the number of parts leads to an increase in failure rates and at the same time, increases costs, making it impossible to provide good brushing over long periods of time at low cost.

With the above-described control, the battery 16 is not always fully charged, and no load or stress is placed on the battery 16. It is possible to control the charging of the battery 16 with a very simple configuration, and the performance of the battery 16 can be maintained over a long period of time. This avoids problems caused by complex charging control, and allows the main unit 1 to provide good brushing at low cost for a long period of time.

Each of the above-described configurations makes it possible to realize a highly reliable ultrasonic toothbrush that has a very simple and inexpensive configuration and that does not impair the desired brushing effect over a long period of time.
Furthermore, the present invention employs the following measures to solve the above-mentioned problems: That is, the toothbrush of the present invention is an ultrasonic toothbrush having a grip portion, a protruding portion protruding from the tip of the grip portion, a vibration portion formed at the tip of the protruding portion and having a vibrator that generates ultrasonic waves disposed thereon, and a bristle portion in which multiple bristle bundles are planted to form a brush, wherein the bristle portion is disposed with a gap between it and the vibration portion and has an opening that communicates with the gap.
Furthermore, the ultrasonic toothbrush of the present invention is characterized in that the bristle unit is detachable from the vibration unit.

REFERENCE SIGNS LIST 1 Main body 11 Grip portion 12 Protrusion portion 13 Brush portion 14 Brush 15 Operation portion 16 Battery 17 Controller 18 Vibrator 19 Vibration portion 20 Harness-B
22 Switch 23 LED section 41 Opening-A
42 Voids-A
43 Hair implantation portion 44 Insertion portion 45 Hair bundle 46 Gap-B
60 Opening-H
61 Opening-B
62 Opening-C
63 Opening-D
64 Pocket 65 Opening-E
66 Flow path-A
67 Opening -F
68 Opening-G
69 Flow path-B
70 Flow path-C
71 Charger 72 Holder 73 Through-hole 74 Power cord 75 Plate surface 76 Power transmission coil 77 Power transmission power source 78 Charging circuit - A
79 Receiving coil 80 Switch element 81 Rectifier circuit 82 Adhesive 83 Charging control unit-A
84 Remaining amount detection unit-A
85 Charging timer 101 Charging circuit - B
102 Remaining amount detection unit-B
103 Charger detection unit 104 Charging control unit-B
201 User IF section 202 Control section 204 Signal generation section 206 Power supply section 207 Timer

Claims (2)

A gripping portion;
a protrusion protruding from the tip of the gripping portion;
a vibration section formed at the tip of the protrusion and having a vibrator disposed therein that generates ultrasonic waves;
a bristle implantation section in which a plurality of bristle bundles are implanted to form a brush;
a brush part in which the bristle part is disposed on a first surface and into which the vibration part is detachably inserted through a first opening;
a gap provided between the vibration section and the bristle section;
An ultrasonic toothbrush characterized in that it has a second opening on the first surface that is different from the first opening and leads to the gap, and a third opening on a second surface of the brush part that is different from the first surface, that is different from the first opening and different from the second opening, leading to the gap . 2. The ultrasonic toothbrush according to claim 1, wherein the brush portion has a flow path connecting the gap and the third opening .