阅读说明：本技术 电动牙刷、系统、刷牙部位检测方法和程序 (Electric toothbrush, system, tooth brushing part detection method, and program ) 是由 吉田秀辉 中西基文 小林达矢 田中孝英 于 2018-06-08 设计创作，主要内容包括：本发明提供电动牙刷、系统、刷牙部位检测方法和程序。本发明的电动牙刷的主体(1)沿着纵轴方向具有刷头部(4)、颈部(3)和握柄部(5),在主体(1)的内部具备用于检测主体(1)的角速度的陀螺仪传感器(16)。根据陀螺仪传感器(16)的输出,求出刷头部(4)的刷毛接触齿列的刷牙部位(BP)时的主体(1)的纵轴与刷头部(4)的刷毛接触齿列的基准位置(BPO)时的主体(1)的纵轴所呈的角度(θ)。根据角度(θ),在与齿列对应弯曲的近似曲线(E1)上求出与刷牙部位(BP)对应的对应点(P),将所述对应点(P)的坐标设为刷牙部位(BP)的平移位置(P)。(The invention provides an electric toothbrush, a system, a tooth brushing part detection method and a program. A main body (1) of an electric toothbrush of the present invention has a brush head portion (4), a neck portion (3), and a grip portion (5) along a longitudinal axis direction, and a gyro sensor (16) for detecting an angular velocity of the main body (1) is provided inside the main body (1). An angle (theta) formed by the longitudinal axis of the main body (1) when the bristles of the brush head part (4) contact the tooth Brushing Part (BP) of the tooth row and the longitudinal axis of the main body (1) when the bristles of the brush head part (4) contact the reference position (BPO) of the tooth row is obtained according to the output of the gyro sensor (16). From the angle (theta), a corresponding point (P) corresponding to the tooth Brushing Part (BP) is obtained on an approximate curve (E1) curved in accordance with the tooth row, and the coordinate of the corresponding point (P) is set as the translational position (P) of the tooth Brushing Part (BP).)

1. An electric toothbrush, comprising:

a body having a head portion having a bristle face on which bristles are arranged upright, a handle portion to be held by a hand, and a neck portion connecting the head portion and the handle portion, along a longitudinal axis direction;

a gyro sensor mounted inside the main body and detecting an angular velocity of the main body; and

a brushing part detecting part for obtaining the translational position of the brushing part in the dentition according to the output of the gyro sensor,

the brushing part detector obtains an angle formed by a longitudinal axis of the main body when the bristles of the brush head part contact the brushing part of the tooth row and a longitudinal axis of the main body when the bristles of the brush head part contact a reference position of the tooth row based on an output of the gyro sensor,

the tooth brushing part detecting unit obtains a corresponding point corresponding to the tooth brushing part on an approximate curve curved in correspondence with the tooth row based on the angle, and sets coordinates of the corresponding point as a translational position of the tooth brushing part.

2. The electric toothbrush according to claim 1, wherein the brushing site detector sets a reference tangent line that is tangent to the approximate curve at a reference point corresponding to the reference position, sets a movable tangent line that is tangent to the approximate curve at the angle to the reference tangent line, and determines a point at which the movable tangent line is tangent to the approximate curve as the corresponding point.

3. The electric toothbrush according to claim 1 or 2, wherein the reference position of the tooth row is a center of a front face of the tooth row.

4. The electric toothbrush according to any one of claims 1 to 3, wherein the brushing site detector sets the approximate curve to be b [ { 1- (x/a) with a function y ═ b, using positive coefficients a and b, in a data space in which an xy rectangular coordinate system is determined²}^1/2－1]A curve corresponding to a portion of an ellipse is shown.

5. The electric toothbrush according to any one of claims 1 to 3, wherein the brushing site detector sets the approximate curve to a function 4py ═ x using a negative coefficient p in a data space in which an xy rectangular coordinate system is determined²The parabola is shown.

6. The electric toothbrush according to claim 4 or 5,

comprises a receiving part capable of receiving setting parameters from the outside of the main body,

the brushing site detecting section can variably set the coefficients a and b or the coefficient p in accordance with the setting parameter received by the receiving section.

7. The electric toothbrush according to any one of claims 1 to 6,

comprising an acceleration sensor loaded inside said body,

the brushing part detector determines a brushing part in the dentition based on an output of the gyro sensor and an output of the acceleration sensor.

8. The electric toothbrush according to claim 7,

the brushing part detector obtains a direction in which the brush of the brush head part faces around the longitudinal axis of the main body based on a direction of gravitational acceleration output from the acceleration sensor, and determines which of the front, rear, and occlusal surfaces of the dentition is brushed according to the direction in which the brush of the brush head part faces,

the brushing part detector identifies a brushing part in the dentition by using a combination of a translational position of the brushing part obtained from an output of the gyro sensor and a determination result of which one of a front surface, a rear surface, and an occlusal surface of the dentition is brushed.

9. The electric toothbrush according to claim 7 or 8,

the brushing part detector calculates a translational movement amount of the main body based on the acceleration of the main body output from the acceleration sensor for each predetermined total unit period,

when the amount of translational movement of the main body is equal to or less than a predetermined first threshold value for a certain total unit period, the brushing site detector performs a first correction process for maintaining the translational position of the brushing site obtained from the output of the gyro sensor in the total unit period.

10. The electric toothbrush according to claim 7 or 8,

the brushing part detector calculates a translational movement amount of the main body based on the acceleration of the main body output from the acceleration sensor for each predetermined total unit period,

when the amount of translational movement of the main body is equal to or greater than a predetermined second threshold value, the brush site detector performs a second correction process of re-finding the corresponding point from the output of the gyro sensor while shifting to a portion of the approximate curve corresponding to the translational movement destination of the main body.

11. The electric toothbrush according to any one of claims 1 to 10, comprising a transmission part capable of transmitting data related to brushing to the outside of the main body.

12. A system comprising the electric toothbrush of claim 11 and a computer device disposed external to a body of the electric toothbrush, the electric toothbrush and the computer device being capable of communicating with each other.

13. The system of claim 12,

a tooth brushing step is established for brushing teeth for a plurality of parts in the dentition in a predetermined sequence and in a predetermined tooth brushing setting period,

the tooth brushing evaluation unit calculates an evaluation value indicating a degree of matching with the tooth brushing procedure based on the tooth brushing site specified by the tooth brushing site detection unit.

14. A tooth brushing part detecting method for detecting a tooth brushing part where an electric toothbrush brushes teeth in a dentition, the tooth brushing part detecting method being characterized in that,

the electric toothbrush includes:

a body having a head portion having a bristle face on which bristles are arranged upright, a handle portion to be held by a hand, and a neck portion connecting the head portion and the handle portion, along a longitudinal axis direction; and

a gyro sensor mounted inside the main body and detecting an angular velocity of the main body,

in the method for detecting the brushing site, the teeth can be brushed,

determining a differential angle between a longitudinal axis of the main body when the bristles of the brush head portion contact a brushing site of the tooth row and a longitudinal axis of the main body when the bristles of the brush head portion contact a reference position of the tooth row, based on an output of the gyro sensor in a real space in which the tooth row exists,

and determining a corresponding point corresponding to the brushing part on an approximate curve curved in accordance with the dentition set in a data space from the differential angle in the real space, and using coordinates of the corresponding point as data indicating a translational position of the brushing part.

15. A program for causing a computer to execute the brushing site detecting method according to claim 14.

Technical Field

The present invention relates to an electric toothbrush, a system, and a tooth brushing part detecting method capable of detecting a tooth brushing part in a tooth row.

Further, the present invention relates to a program for causing a computer to execute such a brushing site detecting method.

Background

Conventionally, for example, in an electric toothbrush disclosed in patent document 1 (japanese patent laid-open publication No. 2009-240759), a toothbrush main body is provided with an acceleration sensor, and dynamic acceleration components in the x-axis direction, the y-axis direction, and the z-axis direction obtained from an output of the acceleration sensor are integrated in the second order to calculate respective moving amounts in the x-axis direction, the y-axis direction, and the z-axis direction, thereby obtaining a brushing site in a dentition (in this document, a translational position in a plane where the dentition is present) during brushing.

Further, this document discloses that the direction of the toothbrush around the vertical axis (y axis) is determined from a gravitational acceleration component obtained from the output of the acceleration sensor (this document is referred to as "brush angle"). It is also disclosed that the toothbrush body further includes a gyro sensor (gyroscope), and the brush angle is obtained by cumulatively adding (integrating) the outputs of the gyro sensors. From the brushing angle thus determined, it is possible to know which of the front, rear, and occlusal surfaces of the tooth is brushed.

Patent document 1: japanese laid-open patent publication No. 2009-240759

Non-patent document 1: sakawa, "cause of mouth-covering-type variation of cause of factor analysis of mouth-covering-type

However, in the electric toothbrush of patent document 1, the output of the acceleration sensor includes a vibration component from a drive motor that vibrates the brush (brush) as noise. Further, in order to determine the translational position of the brushing site, the dynamic acceleration component obtained from the output of the acceleration sensor is subjected to second-order integration, and therefore, the calculation process is greatly affected by noise. Therefore, there is a problem that the accuracy of the obtained translational position of the brushing site is poor.

Disclosure of Invention

Accordingly, an object of the present invention is to provide an electric toothbrush, a system, and a tooth brushing part detecting method capable of accurately determining a translational position of a tooth brushing part in a tooth row.

Further, an object of the present invention is to provide a program for causing a computer to execute such a tooth brushing position detecting method.

In order to solve the problems, the electric toothbrush of the present invention comprises: a body having a head portion having a bristle face on which bristles are arranged upright, a handle portion to be held by a hand, and a neck portion connecting the head portion and the handle portion, along a longitudinal axis direction; a gyro sensor mounted inside the main body and detecting an angular velocity of the main body; and a brushing part detector configured to determine a translational position of a brushing part in the teeth array based on an output of the gyro sensor, wherein the brushing part detector determines an angle between a longitudinal axis of the main body when the bristles of the brush head part contact the brushing part of the teeth array and a longitudinal axis of the main body when the bristles of the brush head part contact a reference position of the teeth array based on the output of the gyro sensor, and wherein the brushing part detector determines a corresponding point corresponding to the brushing part on an approximate curve curved corresponding to the teeth array based on the angle, and sets a coordinate of the corresponding point as the translational position of the brushing part.

In the present specification, the "brushing site" refers to a site brushed (contacted) by the bristles among a plurality of sites defined by dividing the surface of the dentition in the oral cavity. The tooth brushing part in the dentition is determined by the combination of the translational position in the real space where the dentition exists and which of the front, rear, and occlusal surfaces of the dentition is brushed.

The "reference position" of the tooth row means a position in the tooth row which is a reference for measuring the angle.

In the electric toothbrush of the present invention, the brushing site detector obtains the translational position of the brushing site in the dentition from the output of the gyro sensor. That is, the brushing site detector obtains an angle between a longitudinal axis of the main body when the bristles of the brush head part contact the brushing site of the tooth row and a longitudinal axis of the main body when the bristles of the brush head part contact a reference position of the tooth row, based on an output of the gyro sensor. Then, from the angle, a corresponding point corresponding to the tooth brushing part is obtained on an approximate curve curved in correspondence with the tooth row, and coordinates of the corresponding point are set as a translational position of the tooth brushing part.

In such a case, since the output of the gyro sensor is an angular velocity, it is not easy to include a vibration component from a drive motor that vibrates the brush (brush) as noise. Further, since the output of the gyro sensor is an angular velocity, the angle can be obtained by performing first-order integration, and the calculation process is less susceptible to noise. Therefore, the translational position of the brushing part in the tooth row can be accurately obtained.

In the electric toothbrush according to one embodiment, the brushing site detector sets a reference tangent line that is tangent to the approximate curve at a reference point corresponding to the reference position, sets a movable tangent line that is tangent to the approximate curve at the angle to the reference tangent line, and obtains a point at which the movable tangent line is tangent to the approximate curve as the corresponding point.

Here, the "movable tangent line" means a tangent line variably set with a change in the angle, in other words, with a change in the tooth brushing part in the tooth row.

In the electric toothbrush according to the one embodiment, the brushing site detector sets a reference tangent line that is tangent to the approximate curve at a reference point corresponding to the reference position, and sets a movable tangent line that is tangent to the approximate curve at the angle to the reference tangent line. Then, a point at which the movable tangent line is tangent to the approximate curve is obtained as the corresponding point. Thus, the corresponding point on the approximate curve can be obtained by a relatively simple process.

In one embodiment, the reference position of the tooth row is the center of the front face of the tooth row.

In the electric toothbrush according to the above-described embodiment, since the reference position of the tooth row is the center of the front face of the tooth row, it is easy for the user to align the brush of the brush head portion as a site where brushing starts. The brushing site detector can easily determine the translational position of the brushing site by using an analytical expression.

In the electric toothbrush according to one embodiment, the brushing site detector sets the approximation curve to be b [ { 1- (x/a) ] using positive coefficients a and b and a function y, in a data space in which an xy rectangular coordinate system is determined²}^1/2－1]A curve corresponding to a portion of an ellipse is shown.

As is well known in the dental field, the dental arch is approximated by a portion of an ellipse (non-patent document 1). Therefore, in the electric toothbrush according to the above-described one embodiment, the brushing site detecting unit sets the approximate curve to be b [ { 1- (x/a) with a function y ═ b using positive coefficients a and b in a data space in which an xy rectangular coordinate system is determined²}^1/2－1]A curve corresponding to a portion of an ellipse is shown. In this case, the approximation curve can be set to approximate the actual tooth row by determining the coefficients a and b. Therefore, the corresponding point indicating the translational position of the brushing site can be accurately determined on the approximate curve.

In the electric toothbrush according to one embodiment, the brushing site detector sets the approximate curve to a negative coefficient p and a function 4py ═ x in a data space where an xy rectangular coordinate system is determined²The parabola is shown.

As is well known in the dental field, the dental arch can also be approximated by a parabola (non-patent document 1). Therefore, in the electric toothbrush according to the above-described one embodiment, the brushing site detecting unit sets the approximate curve to a negative coefficient p and a function 4py ═ x in a data space where an xy rectangular coordinate system is determined, the approximate curve being set²The parabola is shown. In this case, the approximation curve can be set by determining the coefficient p. Therefore, the processing for finding the corresponding point can be easily performed.

The electric toothbrush of one embodiment includes a receiving part capable of receiving setting parameters from the outside of the main body, and the brushing site detecting part is capable of variably setting the coefficients a and b or the coefficient p corresponding to the setting parameters received through the receiving part.

The electric toothbrush according to the one embodiment includes a receiving unit capable of receiving setting parameters from outside the main body. The brushing site detecting section can variably set the coefficients a and b or the coefficient p in accordance with the setting parameter received by the receiving section. Therefore, the approximate curve can be appropriately set corresponding to the size and shape of the dental arch of various users. In this case, the translational position of the brushing site in the dentition can be further accurately obtained.

The electric toothbrush according to one embodiment includes an acceleration sensor mounted inside the main body, and the brushing site detector determines a brushing site in the dentition based on an output of the gyro sensor and an output of the acceleration sensor.

In the electric toothbrush according to the one embodiment, the brushing site detector determines the brushing site in the dentition based on the output of the gyro sensor and the output of the acceleration sensor. Thus, the tooth brushing part in the tooth row can be determined with high precision.

In an electric toothbrush according to one embodiment, the brushing site detector determines a direction in which bristles of the brush head portion face around a longitudinal axis of the main body based on a direction of gravitational acceleration output from the acceleration sensor, and determines which of a front face, a rear face, and an occlusal surface of the dentition is to be brushed according to the direction in which the bristles of the brush head portion face, and the brushing site detector specifies the brushing site in the dentition based on a combination of a translational position of the brushing site determined based on the output of the gyro sensor and a determination result of which of the front face, the rear face, and the occlusal surface of the dentition is to be brushed.

In the electric toothbrush according to the one embodiment, the brushing site detector obtains a direction in which the brush of the brush head portion faces around the longitudinal axis of the main body based on a direction of gravitational acceleration output from the acceleration sensor, and determines which of the front surface, the rear surface, and the occlusal surface of the dentition is brushed according to the direction in which the brush of the brush head portion faces. Then, the tooth brushing part in the tooth row is specified by a combination of the translational position of the tooth brushing part obtained from the output of the gyro sensor and the determination result of which one of the front, rear, and occlusal surfaces of the tooth row is brushed. Thus, the brushing part in the dentition can be specified with high accuracy.

In an electric toothbrush according to one embodiment, the brushing site detector calculates a translational movement amount of the main body from the acceleration of the main body output from the acceleration sensor every predetermined total unit period, and performs a first correction process of maintaining the translational position of the brushing site obtained from the output of the gyro sensor in the total unit period when the translational movement amount of the main body is equal to or less than a predetermined first threshold value for a certain total unit period.

In the present specification, the "translational movement amount" of the body and the "change amount" of the orientation of the vertical axis of the body in a predetermined total unit period respectively mean the total translational movement amount and the total change amount in the total unit period.

In the electric toothbrush according to the one embodiment, the brushing site detector calculates a translational movement amount of the main body based on the acceleration of the main body output from the acceleration sensor for each predetermined total unit period. In addition, when the translational movement amount of the main body is equal to or less than a predetermined first threshold value for a certain total unit period, the brushing site detector performs a first correction process for maintaining the translational position of the brushing site obtained from the output of the gyro sensor in the total unit period. Therefore, for example, when the user during brushing teeth has largely changed the orientation of the longitudinal axis of the main body (particularly, the brush head) while basically stopping the translational movement of the main body, the translational position of the brushing site obtained from the output of the gyro sensor is maintained before and after the change. This can maintain the accuracy of the obtained translational position of the brushing site.

In an electric toothbrush according to one embodiment, the brushing site detector calculates a translational movement amount of the main body from the acceleration of the main body output from the acceleration sensor every predetermined total unit period, and when the translational movement amount of the main body is equal to or more than a predetermined second threshold, the brushing site detector performs a second correction process of re-finding the corresponding point from the output of the gyro sensor while shifting the portion of the approximate curve corresponding to the translational movement destination of the main body.

In the electric toothbrush according to the one embodiment, the brushing site detector calculates a translational movement amount of the main body based on the acceleration of the main body output from the acceleration sensor for each predetermined total unit period. When the amount of translational movement of the main body is equal to or greater than a predetermined second threshold value, the brush site detector performs a second correction process of re-finding the corresponding point from the output of the gyro sensor while shifting to a portion of the approximate curve corresponding to the translational movement destination of the main body. Therefore, when the user moves the body in translation while the user is brushing the teeth, for example, skipping the anterior labial region from the left buccal region to the right buccal region in the dentition of the upper jaw without substantially changing the orientation of the longitudinal axis of the body, the translation position of the brushing region in the dentition can be accurately obtained.

Further, it is preferable that both the first correction process and the second correction process are performed for each of the total unit periods.

The electric toothbrush according to one embodiment includes a transmission unit capable of transmitting data related to brushing to the outside of the main body.

In the present specification, the "data related to brushing" broadly includes actual brushing time data for each site (data relating a specific brushing site to actual brushing time for the site) and other data related to brushing.

In the electric toothbrush according to the one embodiment, the transmitter may transmit data related to brushing to the outside of the main body. In this case, the data may be received by a computer device provided outside the main body, for example, and used for various processes and purposes.

In another aspect, the system of the present invention includes the electric toothbrush and a computer device disposed external to the body of the electric toothbrush, the electric toothbrush and the computer device being capable of communicating with each other.

The "computer device" may be a computer device that operates substantially as a computer regardless of its name. For example, the mobile terminal can be a smart phone, a tablet terminal, and the like.

In one embodiment, the system comprises a tooth brushing evaluation unit for calculating an evaluation value indicating a degree of matching with the tooth brushing procedure based on the tooth brushing part specified by the tooth brushing part detection unit.

In the system of the one embodiment, a brushing step is prepared for brushing teeth at a plurality of sites in the dentition in a predetermined sequence and for a predetermined brushing setting period. Here, the brushing evaluation unit calculates an evaluation value indicating a degree of matching with the brushing procedure based on the brushing site specified by the brushing site detection unit. Therefore, the user can know the degree of coincidence (or non-coincidence) with the tooth brushing step from the evaluation value.

In another aspect, the brushing site detecting method of the present invention detects a brushing site in a dentition where a tooth is brushed by an electric toothbrush, wherein the electric toothbrush includes: a body having a head portion having a bristle face on which bristles are arranged upright, a handle portion to be held by a hand, and a neck portion connecting the head portion and the handle portion, along a longitudinal axis direction; and a gyro sensor mounted inside the body and detecting an angular velocity of the body, wherein a differential angle between a longitudinal axis of the body when the bristles of the brush head part contact a tooth brushing site of the tooth row and a longitudinal axis of the body when the bristles of the brush head part contact a reference position of the tooth row is determined from an output of the gyro sensor in a real space where the tooth row exists, a corresponding point corresponding to the tooth brushing site is determined on an approximate curve curved in correspondence with the tooth row set in a data space from the differential angle in the real space, and coordinates of the corresponding point are used as data indicating a translational position of the tooth brushing site.

In the tooth brushing part detecting method according to the present invention, a differential angle between a longitudinal axis of the main body when the brush of the brush head portion contacts the tooth brushing part of the tooth row and a longitudinal axis of the main body when the brush of the brush head portion contacts a reference position of the tooth row is determined based on an output of the gyro sensor in a real space where the tooth row exists. Then, from the differential angle in the real space, a corresponding point corresponding to the tooth brushing part is obtained on an approximate curve curved in accordance with the tooth row set in a data space, and coordinates of the corresponding point are used as data indicating a translational position of the tooth brushing part.

In such a case, since the output of the gyro sensor is an angular velocity, it is not easy to include a vibration component from a drive motor that vibrates the brush (brush) as noise. In addition, since the output of the gyro sensor is an angular velocity, the differential angle can be obtained by performing first-order integration, and the calculation process is not easily affected by noise. Therefore, the translational position of the brushing part in the tooth row can be accurately obtained.

In another aspect, the program of the present invention is a program for causing a computer to execute the brushing site detecting method.

According to the program of the present invention, the computer can be caused to execute the brushing site detecting method.

As is apparent from the above description, according to the electric toothbrush, the system, and the brushing part detecting method of the present invention, the translational position of the brushing part in the dentition can be obtained with high accuracy.

Further, according to the program of the present invention, it is possible to cause a computer to execute such a tooth brushing position detecting method.

Drawings

Fig. 1(a) and 1(B) are views showing the appearance of the electric toothbrush according to the embodiment of the present invention, as viewed obliquely from opposite sides to each other.

Fig. 2 is a vertical cross-section of the electric toothbrush taken along the vertical axis.

Fig. 3 is a block diagram showing a control system of the electric toothbrush.

Fig. 4 is a diagram showing a schematic flow of a brushing site detection method according to an embodiment of the present invention, that is, a process for specifying a brushing site in a dentition by using the electric toothbrush.

Fig. 5 is a diagram showing the detailed flow of the process of determining the translational position of the brushing site (step S2) shown in fig. 4.

Fig. 6 is a view showing 16 sites in the dentition in the oral cavity.

Fig. 7(a) is a diagram showing an approximate curve of "standard" as a part of an ellipse. Fig. 7(B) is a diagram showing an approximate curve of "longitudinal length" which is a part of another ellipse. Fig. 7(C) is a diagram showing a "small" approximate curve as a part of another ellipse.

Fig. 8 is a diagram illustrating a differential angle θ between the longitudinal axis (Y axis) of the main body when the bristles of the brush head contact the tooth row at the brushing site and the longitudinal axis (Y axis) of the main body when the bristles of the brush head contact the reference position of the tooth row in real space.

Fig. 9 is a diagram for explaining a process of obtaining a corresponding point corresponding to a brushing site on an approximate curve of "standard" in a data space from the differential angle θ.

Fig. 10 is a view showing the direction of the gravitational acceleration G output from the acceleration sensor when viewed from the brush head side (+ Y direction) in a state where the longitudinal axis (Y axis) of the main body is in a horizontal posture.

Fig. 11 is a diagram showing a state in which the brush head portion (+ Y direction) is arranged to the left with respect to the face of the user, in the line of sight of the user.

Fig. 12 is a diagram showing a state in which the brush head portion (+ Y direction) is arranged rightward with respect to the face of the user, under the line of sight of the user.

Fig. 13(a) to 13(C) are views showing the zones to be brushed for determining which of the front, rear, and occlusal surfaces of the "left rear teeth" of the tooth row of the upper jaw is brushed. Fig. 13(D) to 13(F) are views showing the divisions where the brush is applied to one of the front, rear, and occlusal surfaces of the "left rear teeth" for determining the tooth arrangement of the lower jaw.

Fig. 14(a) to 14(B) are views of the brush segment for determining which of the front and rear surfaces of the "front teeth" of the tooth row of the upper jaw is brushed. Fig. 14(C) to 14(D) are views of the brush segment for determining which of the front and rear surfaces of the "front teeth" of the tooth row of the lower jaw is brushed.

Fig. 15(a) to 15(C) are views for determining which of the front, rear, and occlusal surfaces of the "right rear teeth" of the tooth row of the upper jaw is brushed. Fig. 15(D) to 15(F) are views for determining which of the front, rear, and occlusal surfaces of the "right rear teeth" of the tooth row of the lower jaw is brushed.

Fig. 16 is a diagram exemplarily showing a state in which the orientation of the longitudinal axis (Y axis) of the main body is largely changed in a state in which the user substantially stops the translational movement of the brush head part during brushing.

Fig. 17 is a diagram exemplarily showing a state in which the user moves the main body in a large translational motion by skipping the part without substantially changing the orientation of the longitudinal axis (Y axis) of the main body during brushing.

Fig. 18 is a diagram showing a flow of the correction process.

Fig. 19 is a diagram illustrating a process of obtaining a corresponding point corresponding to a brushing site on a parabola, which is an approximate curve, in a data space based on the differential angle θ.

Fig. 20 is a diagram exemplarily showing a configuration of a system including the electric toothbrush and a smartphone.

Description of the reference numerals

1. 600M Main body

3 neck part

4 brush head

5 handle part

15 acceleration sensor

16 gyroscopic sensor

90 electric toothbrush

110. 610 control part

210 bristles

600 smart phone

640 display

700 system

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Structure of electric toothbrush)

Fig. 1 a and 1B show the appearance of an electric toothbrush (indicated by reference numeral 90 as a whole) incorporating an embodiment of a tooth deposit detection device of the present invention, as viewed obliquely from opposite sides to each other. The electric toothbrush 90 includes a brush head portion 4 in which bristles 210 are vertically arranged along a longitudinal axis direction (Y-axis direction), a grip portion 5 to be held by a hand, and a neck portion 3 connecting the brush head portion 4 and the grip portion 5. The brush head portion 4 and the neck portion 3 are integrally formed as a brush member 2 that can be attached to and detached from the grip portion 5. The brush head portion 4, neck portion 3, and handle portion 5 are collectively referred to as a body 1. To facilitate tooth brushing, the main body 1 has an elongated shape in the Y-axis direction. In addition, fig. 1(a) illustrates a charger 100.

Fig. 2 shows a vertical section of the electric toothbrush 90 taken along the vertical axis (Y axis). The grip portion 5 has a stem 6, and the stem 6 is provided to protrude from an outer frame body of the grip portion 5 toward the neck portion 3. The stem 6 has a cylindrical shape with a closed top end. In this example, the neck portion 3 of the toothbrush member 2 is fitted and attached so as to cover the stem 6. The toothbrush member 2 is a consumable part, and is configured to be detachable from the grip portion 5 so as to be replaceable with a new one. In this example, bristles 210 are set upright by implanting on a surface (raised surface) 4a on one side of the head portion 4 of the toothbrush member 2 so as to protrude from the raised surface 4a by about 10mm to 12 mm. The brush staples 210 may be welded or bonded without being implanted.

A power switch S for turning on and off the power supply is provided on the outer surface of the grip portion 5 of the main body 1. Further, a motor 10 as a driving source, a driving circuit 12, a charging battery 13 as a power source, a coil 14 for charging, an acceleration sensor 15, a gyro sensor 16, and the like are mounted inside the grip portion 5. When charging the secondary battery 13, the main body 1 can be charged contactlessly by electromagnetic induction simply by being carried by the charger 100 shown in fig. 1 (a).

As shown in fig. 2, a bearing 203 is provided inside the stem 6. The top end of eccentric shaft 30 connected to rotating shaft 11 of motor 10 is inserted into bearing 203. Eccentric shaft 30 has a weight 300 in the vicinity of bearing 203, and the center of gravity of eccentric shaft 30 is offset from the center of rotation. When the drive circuit 12 supplies a drive signal (for example, a pulse width modulation signal) corresponding to the operation mode to the motor 10 to rotate the rotary shaft 11 of the motor 10, the eccentric shaft 30 is also rotated along with the rotation of the rotary shaft 11. Since the center of gravity of the eccentric shaft 30 is offset from the center of rotation, a motion of rotating around the center of rotation is performed. Therefore, the tip of the eccentric shaft 30 repeatedly collides against the inner wall of the bearing 203, and the brush 210 is vibrated (moved) at high speed.

In this example, the acceleration sensor 15 is made of a commercially available product of the mems (micro Electro Mechanical systems) type, and outputs signals indicating the acceleration of X, Y, Z in three axes. X, Y, Z denotes a rectangular coordinate system fixed to the body 1. In this example, as shown in fig. 1(a), the X axis is parallel to the raised surface 4a, the Y axis is aligned with the direction from the grip portion 5 to the brush head portion 4 in the longitudinal direction of the main body 1, and the Z axis is aligned with the direction from the raised surface 4a to the distal ends of the bristles 210. For example, when the main body 1 is placed on the charger 100, the gravity acceleration vector is in the-Y direction, and when the tip of the brush 210 is directed downward, the gravity acceleration vector is in the + Z direction. The outputs of the axes of the acceleration sensor 15 are input to a control unit 110 (described later) for specifying a brushing site (described later in detail).

In this example, the gyro sensor 16 is made of a commercially available MEMS type, and outputs signals indicating X, Y, Z three-axis angular velocities, that is, an angular velocity around the Z axis, an angular velocity around the X axis, and an angular velocity around the Y axis. The outputs of the axes of the gyro sensor 16 are input to a control unit 110 (described later) and used together with the output of the acceleration sensor 15 to specify a brushing site (described later).

Further, whether or not the brush 210 actually contacts the brushing site is detected by a load sensor (not shown) mounted in the main body 1 (detecting a load applied to the brush 210).

Fig. 3 shows a modular structure of a control system of the electric toothbrush 90. The electric toothbrush 90 includes a control unit 110, a storage unit 115, an operation unit 130, a notification unit 140, a communication unit 180, and a power supply unit 170, which form the drive circuit 12, in addition to the acceleration sensor 15 and the gyro sensor 16. The driving unit 101 is the motor 10, the rotating shaft 11, the eccentric shaft 30, the bearing 203, and the weight 300.

In this example, the control unit 110 includes a CPU (central processing unit) operated by software, and executes various processes such as a process for specifying a tooth brushing part in a tooth row and others, in addition to the drive of the motor 10. The control unit 110 incorporates a timer for measuring time.

The operation unit 130 includes the power switch S, and allows the user to turn on or off the power of the electric toothbrush 90.

In this example, the storage unit 115 includes an EEPROM (electrically rewritable nonvolatile memory) capable of storing data non-temporarily. The storage unit 115 stores a control program for controlling the control unit 110. In this example, data related to brushing is stored in the storage unit 115 as a table (described later), and the data related to brushing is, for example, data indicating actual brushing time for each part in the dentition (referred to as "actual brushing time data") accompanying brushing.

In this example, the notification unit 140 includes a red LED (light Emitting diode) lamp 140R and a green LED lamp 140G (see fig. 1 a), and notifies the brushing progress with respect to a predetermined brushing step by turning on and off the LEDs 140R and 140G. The notification unit 140 may include a buzzer (not shown) for notifying the progress of brushing with respect to the brushing steps by sounding the buzzer.

The communication unit 180 is controlled by the control unit 110, and transmits various information (actual brushing time data and the like) to an external device via a network as a transmission unit, and receives various information (setting parameters and the like described later) from an external device via a network as a reception unit, and transmits the information to the control unit 110. In this example, the communication via the network is wireless communication (for example, BT (registered trademark) communication, BLE (registered trademark) low energy communication, or the like). Typical networks include a home LAN (local Area network) and a hospital LAN, but are not limited thereto, and may be the internet or the like.

The power supply unit 170 includes the rechargeable battery 13 and supplies power (in this example, DC voltage) to the various units in the electric toothbrush 90.

(divisions in dentition)

In this example, as shown in fig. 6, the upper and lower tooth rows 98U and 98L are divided into 16 regions SQ1, SQ2, … …, and SQ16 (boundaries between adjacent regions are indicated by broken lines). The upper dentition 98U includes a left buccal portion SQ1, a left occlusal portion SQ8, and a left lingual portion SQ7 in the left rear teeth, an anterior labial portion SQ2 and an anterior lingual portion SQ6 in the front teeth, and a right buccal portion SQ3, a right occlusal portion SQ4, and a right lingual portion SQ5 in the right rear teeth. The dentition 98L of the mandible includes a left buccal portion SQ9, a left occlusal portion SQ16, and a left lingual portion SQ15 at the left rear teeth, an anterior labial portion SQ10, and an anterior lingual portion SQ14 at the anterior teeth, and a right buccal portion SQ11, a right occlusal portion SQ12, and a right lingual portion SQ13 at the right rear teeth.

The upper jaw teeth row 98U includes 3 "front teeth" on each of the left and right sides, and 6 "front teeth" in total. The upper jaw teeth 98U include 5 "left rear teeth" and "right rear teeth", respectively. The "left posterior teeth", "anterior teeth", and "right posterior teeth" demarcate the range of translational positions along the dental arch. In the tooth row 98U of the upper jaw, the range of the "front teeth" is divided into ranges of 20mm to the left and right from the reference position BP0, which is the center of the front surface (i.e., ranges of 40mm in width to the left and right). The "left rear tooth" is partitioned to a range exceeding 20mm leftward from the front center BP 0. The "right rear tooth" is partitioned to a range exceeding 20mm rightward from the front center BP 0. The same is true of the described divisions in the lower jaw row 98L.

In short, the upper jaw teeth row 98U and the lower jaw teeth row 98L are divided into sections as shown in table 1 below by a combination of the range of the translational position along the dental arch and the anterior surface, the occlusal surface, or the posterior surface. Here, the body of table 1 shows the numbers SQ1 to SQ16 of the respective regions, and the numbers SQ1 to SQ16 of the respective regions are determined by the combination of the range of the translation positions listed in the head ("left rear tooth", "front tooth", and "right rear tooth") and which of the "front face", "occlusal face", and "rear face" listed in the front side column. In addition, the "front teeth" are not provided with a portion (a section) corresponding to the combination with the "occlusal surface" (indicated by a symbol "-").

(Table 1) subdivision of dentition

The division of the tooth row is not limited to this, and may be further divided. For example, each tooth may be divided along the arch, or each tooth may be divided into left and right halves.

(method of detecting brushing site)

Fig. 4 shows a schematic flow of a process in which the controller 110 of the electric toothbrush 90 specifies a brushing site in the tooth rows 98U and 98L as a brushing site detection method according to one embodiment. In this example, the brushing steps are set in advance such that the teeth are brushed in the order of increasing numbers from part SQ1 to part SQ8 in the dentition 98U of the upper jaw and from part SQ9 to part SQ16 in the dentition 98L of the lower jaw as shown in fig. 6.

In the flow of fig. 4, if the user turns on the power switch S of the electric toothbrush 90, the control unit 110 rotates the motor 10 to vibrate the brush 210. Here, according to the above-described tooth brushing procedure, at the time (instant) when the power switch S is turned on, the user brings the brush 210 of the brush head portion 4 into contact with the reference position BP0 (see fig. 8) which is the center of the front face of the tooth row 98U. It is easy for the user to align the bristles 210 of the brush head 4 with the reference position BP 0. As shown in step S1 of fig. 4, the control unit 110 starts the measurement of the brushing time by the built-in timer.

Next, as shown in step S2, the control unit 110 operates as a brushing part detecting unit to determine a translational position (described later in detail) of a brushing part (indicated by the reference numeral "BP") in the tooth row 98U or 98L (initially defined as the tooth row 98U of the upper jaw) based on the output of the gyro sensor 16.

Next, as shown in step S3, the control unit 110 operates as a brushing area detecting unit, determines the direction (+ Z direction) in which the brush bristles 210 of the brush head unit 4 face around the longitudinal axis (Y axis) of the main body 1 from the output of the acceleration sensor 15, and determines which of the front, rear, and occlusal surfaces of the tooth row 98U or 98L is brushed (to be described later) from the direction (+ Z direction) in which the brush bristles 210 of the brush head unit 4 face.

Next, as shown in step S4, the control unit 110 operates as a brushing part detecting unit, and determines the brushing part BP in the tooth row 98U or 98L by using a combination of the translational position of the brushing part BP obtained from the output of the gyro sensor 16 and the determination result of which of the front, rear, and occlusal surfaces of the tooth row 98U or 98L is brushed.

Next, as shown in step S5, the control unit 110 determines whether or not the brushing setting period for the specific brushing part BP has elapsed, based on the measurement result of the time by the built-in timer. If the brushing setting period for the site BP has not elapsed (no in step S5), the processing of steps S2 to S5 is repeated. In this example, control unit 110 repeats the processing of steps S2 to S5 every 0.1 second, which is a processing unit period.

Next, if the brushing setting period for the specific brushing site BP has elapsed (yes in step S5), the control unit 110 notifies the user that the brushing setting period for the site BP has elapsed by temporarily lighting the green LED lamp 140G included in the notification unit 140 for about 0.2 seconds, for example (step S6). When the user continues to brush teeth for the region BP for more than 1 second, for example, in the brushing setting period (no in step S7), the user may be warned by temporarily lighting the red LED lamp 140R for about 0.2 seconds, for example, in step S6 to prevent excessive brushing. Further, the buzzer included in the notification unit 140 may be sounded together with the LED lamp 140G or 140R being temporarily turned on, to notify the tooth brushing progress with respect to the tooth brushing step.

Next, if the user moves the brush head part 4 to the "next site" of the specific brushing site BP in the teeth row 98U or 98L (yes in step S7), the control part 110 associates the specific brushing site BP with the actual brushing time for the site BP, and records the actual brushing time data for each site in the table prepared in the storage part 115 (step S8). In addition, other information related to brushing may be recorded in the storage unit 115.

Subsequently, returning to step S1, the control unit 110 starts the measurement of the brushing time by the built-in timer for the "next site".

Thus, the brushing part BP in the tooth row 98U or 98L is sequentially specified, and the actual brushing time data of each part is sequentially recorded. If the brushing step is completed or the power switch S is turned off (step S9), the process is terminated.

(processing for finding the translational position of brushing part)

The processing of step S2 shown in fig. 4 (processing for obtaining the translational position of the brushing site from the output of the gyro sensor 16) will be described with reference to the detailed flow of fig. 5.

i) First, as shown in step S21 of fig. 5, the control unit 110 operates as a brushing site detecting unit, and as shown in fig. 9, an approximate curve E1 is set in the data space DS in which the xy rectangular coordinate system is determined, the approximate curve E1 corresponding to a part of the ellipse E curved in correspondence with the tooth rows 98U, 98L.

Specifically, as is well known in the dental field, the dental arch is approximated by a portion of an ellipse (non-patent document 1). Therefore, in this example, as shown in fig. 7(a), a portion having a depth D1 ≈ 50mm and a width W1 ≈ 70mm in an ellipse E having a short diameter 2a of 71.76mm and a long diameter 2b of 128.2mm is used as the approximate curve E1 so as to correspond to a "normal" tooth row.

In this example, as shown in fig. 9, the approximate curve E1 is set so as to be convex at the origin O (0, 0) as the reference point, and tangent to the x-axis. For an ellipse E that is tangent to the x-axis in a convex form at the origin O (0, 0), coefficients where a and b are positive (i.e., a > 0 and b > 0) are expressed as

(x/a)²+{(y+b)/b}²＝1

…(Eq.1)。

In particular, an approximate curve E1 corresponding to a portion of the ellipse E that is convex upward is expressed as an explicit function

y＝b[{1²－(x/a)²}^1/2－1]

…(Eq.1′)。

In this case, the approximation curve E1 can be set to approximate the actual tooth rows 98U and 98L by determining the coefficients a and b. Therefore, the corresponding point P indicating the translational position of the brushing site can be accurately obtained on the approximate curve E1.

Further, the process of step S21 may not be executed each time the process of step S2 is executed, but the process of step S21 may be executed only once after the power is turned on. In this example, the setting of the approximate curve E1 in the data space DS means that the approximation curve E1 is set to beCoordinates (x) of a point column forming the approximate curve E1_i，y_i) (i is 0, 1, 2, … …) stored in the storage unit 115. The data of the approximate curve E1 may be stored in the storage unit 115 in advance.

ii) next, as shown in step S22 of fig. 5, the controller 110 operates as a brushing area detector, and as shown in fig. 8, in the real space RS in which the tooth row 98U or 98L (the tooth row 98U is shown in the example of fig. 8), the difference angle θ between the vertical axis (Y axis) Y1 of the main body 1 when the brush 210 of the brush head unit 4 contacts the brushing area BP of the tooth row 98U or 98L and the vertical axis (Y axis) Y0 of the main body 1 when the brush 210 of the brush head unit 4 contacts the reference position BP0 of the tooth row 98U is determined based on the output of the gyro sensor 16.

Specifically, in this example, as described above, at the time (instant) when the power switch S is turned on, the user brings the brush 210 of the brush head portion 4 into contact with the reference position BP0, which is the center of the front surface of the tooth row 98U. Subsequently, the user brings the bristles 210 of the brush head 4 into contact with the other part (brushing part) BP of the tooth row 98U or 98L in accordance with the brushing step. Accordingly, the longitudinal axis (Y axis) Y1 of the main body 1 when the bristles 210 of the brush head 4 contact the brushing area BP of the tooth row 98U or 98L forms an angle (differential angle) θ with the longitudinal axis (Y axis) Y0 of the main body 1 when the bristles 210 of the brush head 4 contact the reference position BP0 of the tooth row 98U. The control unit 110 obtains the differential angle θ from the output (angular velocity) of the gyro sensor 16. Here, since the output of the gyro sensor 16 is an angular velocity, the difference angle θ can be obtained by performing first-order integration.

The control unit 110 may execute the process of step S21 in fig. 5 in parallel with the process of step S22, or may execute the process of step S22 prior to the process of step S21.

iii) next, as shown in steps S23 and S24 of fig. 5, the controller 110 operates as a brushing site detector, and sets a reference tangent line (corresponding to the x-axis in this example) that is tangent to the approximate curve E1 at the origin O corresponding to the reference position BP0 and a movable tangent line Q that is tangent to the approximate curve E1 at the difference angle θ from the reference tangent line (x-axis) in the data space DS as shown in fig. 9. Here, the movable tangent line Q is variably set with a change in the differential angle θ, in other words, with a change in the tooth brushing part BP in the tooth row 98U or 98L. Then, the control unit 110 obtains a point at which the movable tangent line Q is tangent to the approximate curve E1 as a corresponding point P (step S25 in fig. 5). Thus, the corresponding point P on the approximation curve E1 can be obtained by a relatively simple process.

Specifically, as shown in fig. 9, a certain movable tangent line Q and the approximate curve E1 are set at a point P (x)₁，y₁) Is tangent to each other. The equation of the movable tangent line Q is expressed by a mathematical formula

xx₁/a²+(y+b)(y₁+b)/b²＝1

…(Eq.2)。

In addition, since the point P (x)₁，y₁) Is a point on the ellipse E, the following equation holds.

(x₁/a)²+{(y₁+b)/b}²＝1

…(Eq.3)。

Here, the inclination of the movable tangent line Q is represented as m according to the formula (eq.2)

m＝－b²x₁/a²(y₁+b)

…(Eq.4)。

Using equations (Eq.3) and (Eq.4), the coordinate x of tangent point P to approximate curve E1₁、y₁The inclination m indicates the following.

x₁＝－a²m/{a²m²+b²}^1/2

y₁＝－b+b²/{a²m²+b²}^1/2

…(Eq.5)。

The inclination m is represented by "tan θ", where θ represents the angle formed by the movable tangent line Q and the x-axis (positive in the counterclockwise direction, -pi/2 ≦ theta ≦ pi/2). The formula (Eq.5) is shown below.

x₁＝－a²(tanθ)/{a²(tanθ)²+b²}^1/2

y₁＝－b+b²/{a²(tanθ)²+b²}^1/2

…(Eq.6)。

According to the above equation (Eq.6), the coordinate (x) of the corresponding point P corresponding to the tooth brushing part BP on the approximate curve E1 is obtained in the data space DS based on the difference angle theta in the real space RS₁，y₁). Coordinate (x) of the corresponding point P₁，y₁) As data representing the translational position of the brushing site BP. Thus, the translational position of the brushing site BP can be easily determined by the analytical expression (eq.6). In particular, the center of the front face of the tooth row 98U is set to the reference position BP0, thereby simplifying the equation (eq.6). The center of the front face of the tooth row 98L may be set as the reference position BP 0.

In such a case, since the output of the gyro sensor 16 is an angular velocity, it is not easy to include a vibration component from the driving unit 101 (the motor 10) as noise. Since the output of the gyro sensor 16 is an angular velocity, the differential angle θ can be obtained by first-order integration, and the calculation process is less susceptible to noise. Therefore, the translational position of the brushing site BP in the tooth row 98U or 98L can be accurately obtained.

If the coordinate (x) of the corresponding point P is obtained according to the formula (Eq.6)₁，y₁) The translational position of the brushing site BP is determined as to which section of "left rear tooth", "front tooth", and "right rear tooth" shown in table 1 belongs.

For example, if the differential angle θ in the real space RS is 60 °, the coordinates (x) of the corresponding point P in the data space DS are accompanied by this₁，y₁) And (-25.0, -18.1) (unit mm), the translational position of brushing site BP belongs to the "left rear tooth" partition. If the differential angle θ in the real space RS is 45 °, the coordinates (x) of the corresponding point P in the data space DS are accordingly obtained₁，y₁) And (-17.5, -8.2) (unit mm), the translational position of brushing site BP belongs to the "front teeth" partition. If the differential angle θ in the real space RS is-60 °, the coordinates (x) of the corresponding point P in the data space DS are obtained accordingly₁，y₁) And ≈ (25.0, -18.1) (unit mm), the translational position of brushing site BP belongs to the "right rear tooth" partition.

(determination of which of the front, rear, and occlusal surfaces is brushed)

Next, the processing of step S3 shown in fig. 4 will be described specifically, i.e., the processing of determining the direction (+ Z direction) in which the brush staples 210 of the brush head unit 4 face around the longitudinal axis (Y axis) of the main body 1 based on the output of the acceleration sensor 15, and determining which of the front, rear, and occlusal surfaces of the tooth rows 98U or 98L is brushed based on the direction (+ Z direction) in which the brush staples 210 of the brush head unit 4 face, using fig. 6 and 10 to 15.

In the tooth brushing step described with reference to fig. 6, the teeth are brushed in the ascending order of the numerals from portions SQ1 to SQ8 in the dentition 98U of the upper jaw, and then from portions SQ9 to SQ16 in the dentition 98L of the lower jaw. Further, in the above-described tooth brushing step, when brushing teeth for each of the regions SQ1 to SQ16, as shown by (HL) or (HR) indicated by parentheses in fig. 6, the brush head 4(+ Y direction) is set to be either arranged to the left or the right with respect to the face of the user in a state where the vertical axis (Y axis) of the main body 1 is in a horizontal posture. Reference numeral HL denotes, as shown in fig. 11, that the brush head portion 4(+ Y direction) is arranged toward the left with respect to the face of the user. On the other hand, reference numeral HR denotes that the brush head portion 4(+ Y direction) is arranged to face right with respect to the face of the user, as shown in fig. 12. As can be seen from fig. 6, when brushing the teeth at the positions SQ1, SQ7, SQ8, SQ9, SQ15, and SQ16 partitioned into "left rear teeth", the brush head 4(+ Y direction) is set to face the left HL. On the other hand, when brushing the teeth at the sites SQ3, SQ4, SQ5, SQ11, SQ12, and SQ13 divided into "right rear teeth", the brush head 4(+ Y direction) is set to be arranged facing the right HR. The setting is necessary for brushing the teeth of the left back tooth and the right back tooth respectively. In addition, when brushing the teeth of the sites SQ2, SQ6, SQ10 and SQ14 partitioned into "front teeth", the present example is set to the same orientation as the orientation of the sites before brushing the teeth. That is, when brushing teeth at positions SQ2 and SQ10, the brush head 4(+ Y direction) is set to face the left HL. When brushing teeth at positions SQ6 and SQ14, the brush head 4(+ Y direction) is set to face the right HR.

Fig. 10 shows the direction of the gravitational acceleration G output from the acceleration sensor 15 when viewed from the brush head 4 side (+ Y direction) in a state where the vertical axis (Y axis) of the main body 1 is in a horizontal posture. As can be seen from fig. 10, the direction (+ Z direction) in which the brush 210 of the brush head portion 4 faces around the longitudinal axis (Y axis) of the main body 1 in accordance with the direction of the gravitational acceleration G output from the acceleration sensor 15 is represented as a rotation angle around the longitudinal axisIn this example, with the vertical lower side set at 0 °, as shown in fig. 10, the longitudinal axis (Y axis) of the main body 1 is set in a horizontal posture, and the rotation angle around the longitudinal axis is observed from the brush head portion 4 side (+ Y direction)The value is in the range of 0 DEG to 359.99 DEG counterclockwise (to two decimal points or less).

Fig. 13(a) to 13(C) show the subareas for determining which of the front, rear, and occlusal surfaces of the "left rear teeth" of the tooth row 98U of the upper jaw is brushed. In a state where the longitudinal axis (Y axis) of the main body 1 is in a horizontal posture and the brush head 4(+ Y direction) is arranged to face the left HL with respect to the face of the user, as shown in fig. 13(a), the rotation angle about the longitudinal axis is only requiredWithin the range of 90 ° to 135 °, it is determined that the front face (hence, the left buccal portion) SQ1 is brushed. In this state, as shown in FIG. 13(B), only the angle of rotation about the longitudinal axis is requiredWithin the range of 135 ° to 225 °, it is judged that the occlusal surface (therefore, the left occlusal surface portion) SQ8 is brushed. In this state, as shown in FIG. 13(C), only the rotation angle around the longitudinal axis is requiredWithin the range of 225 ° to 270 °, it is judged that the rear face (hence, the left lingual portion) SQ7 is brushed.

Similarly, fig. 13(D) to 13(F) show the divisions to be brushed for determining which of the front, rear, and occlusal surfaces of the "left rear teeth" of the teeth row 98L of the lower jaw is brushed. In a state where the longitudinal axis (Y axis) of the main body 1 is in a horizontal posture and the brush head 4(+ Y direction) is arranged to face the left HL with respect to the face of the user, as shown in fig. 13(D), the rotation angle about the longitudinal axis is only requiredWithin the range of 45 ° to 90 °, it is judged that the front face (hence, the left buccal portion) SQ9 is brushed. In this state, as shown in FIG. 13(E), only the rotation angle about the longitudinal axis is requiredIn the range of 0 ° to 45 ° or 315 ° to 359.99 °, it was judged that the occlusal surface (therefore, the left occlusal surface portion) SQ16 was brushed. In this state, as shown in FIG. 13(F), only the rotation angle around the longitudinal axis is requiredWithin the range of 270 ° to 315 °, it is determined that the rear face (hence, the left lingual portion) SQ15 is brushed.

Fig. 14(a) to 14(B) show the brush segments for determining which of the front and rear surfaces of the "front teeth" of the upper jaw teeth row 98U is brushed. In a state where the longitudinal axis (Y axis) of the main body 1 is in a horizontal posture and the brush head 4(+ Y direction) is arranged to face the left HL with respect to the face of the user, as shown in fig. 14(a), the rotation angle about the longitudinal axis is only requiredWithin the range of 90 ° to 180 °, the front face (hence the front lip side portion) SQ2 was judged to be brushed. In addition, in the state, the tooth brushing step is separated, only the rotation angle around the longitudinal axis is neededWithin the range of 180 ° to 270 °, it is judged that the rear face (hence, the anterior lingual portion) SQ6 is brushed. On the other hand, the brush head 4(+ Y direction) takes a horizontal posture with respect to the user in the longitudinal axis (Y axis) of the main body 1In the state where the face of (a) is arranged facing the right HR, as shown in FIG. 14(B), only the angle of rotation about the longitudinal axisWithin the range of 90 ° to 180 °, it is judged that the rear face (hence, the anterior lingual portion) SQ6 is brushed. In addition, in the state, the tooth brushing step is separated, only the rotation angle around the longitudinal axis is neededWithin the range of 180 ° to 270 °, it is judged that the front face (hence the front lip side portion) SQ2 is brushed.

Similarly, fig. 14(C) to 14(D) show the divisions for determining which of the front and rear faces of the "front teeth" of the tooth row 98L of the lower jaw is brushed. In a state where the longitudinal axis (Y axis) of the main body 1 is in a horizontal posture and the brush head 4(+ Y direction) is arranged to face the left HL with respect to the face of the user, as shown in fig. 14(C), the rotation angle about the longitudinal axis is only requiredWithin the range of 0 ° to 90 °, it is judged that the front face (hence, the front lip side portion) SQ10 is brushed. In addition, in the state, the tooth brushing step is separated, only the rotation angle around the longitudinal axis is neededWithin the range of 270 ° to 359.99 °, it is judged that the rear face (hence, the anterior lingual portion) SQ14 is brushed. On the other hand, in a state where the longitudinal axis (Y axis) of the main body 1 is in a horizontal posture and the brush head 4(+ Y direction) is arranged to face the right HR with respect to the face of the user, as shown in fig. 14(D), the rotation angle about the longitudinal axis is only requiredWithin the range of 0 ° to 90 °, it is judged that the rear face (hence, the anterior lingual portion) SQ14 is brushed. In addition, in the state, the tooth brushing step is separated, only the rotation angle around the longitudinal axis is neededIn 270 ° -EWhen the angle is 359.99 °, the front face (hence the front lip side portion) SQ10 is judged to be brushed.

Fig. 15(a) to 15(C) show the divisions to be brushed for determining which of the front, rear, and occlusal surfaces of the "right rear teeth" of the tooth row 98U of the upper jaw is brushed. In a state where the longitudinal axis (Y axis) of the main body 1 is in a horizontal posture and the brush head 4(+ Y direction) is arranged to face the right HR with respect to the face of the user, as shown in fig. 15(a), the rotation angle about the longitudinal axis is only requiredWithin the range of 90 ° to 135 °, it is judged that the rear face (hence, the right lingual portion) SQ5 is brushed. In this state, as shown in FIG. 15(B), only the angle of rotation about the longitudinal axis is requiredWithin the range of 135 ° to 225 °, it is judged that the occlusal surface (therefore, the right occlusal surface portion) SQ4 is brushed. In this state, as shown in FIG. 15(C), only the rotation angle around the longitudinal axis is requiredWithin the range of 225 ° to 270 °, the front (hence, the right buccal region) SQ3 was judged to be brushed.

Similarly, fig. 15(D) to 15(F) show the divisions to be brushed for determining which of the front, rear, and occlusal surfaces of the "right rear teeth" of the tooth row 98L of the lower jaw is brushed. In a state where the longitudinal axis (Y axis) of the main body 1 is in a horizontal posture and the brush head 4(+ Y direction) is arranged to face the right HR with respect to the face of the user, as shown in fig. 15(D), the rotation angle about the longitudinal axis is only requiredWithin the range of 45 ° to 90 °, it is judged that the rear face (hence, the right lingual portion) SQ13 is brushed. In this state, as shown in FIG. 15(E), only the rotation angle about the longitudinal axis is requiredIn the range of 0 to 45 DEG or 315 to 359.99 DEG, the occlusal surface (therefore, the right occlusal surface) is judgedSite) SQ12 was brushed. In this state, as shown in FIG. 15(F), only the rotation angle around the longitudinal axis is requiredWithin the range of 270 ° to 315 °, the front (hence, the right buccal region) SQ11 was judged to be brushed.

In general, the angle of rotation about the longitudinal axisThe correspondence with the anterior, posterior and occlusal surfaces is shown in table 2 below. Here, the body of table 2 indicates a rotation angle around the longitudinal axis when the brush head portion 4(+ Y direction) is arranged to face left HL or right HRThe table side columns of Table 2 show the angles of rotation about the longitudinal axisThe front, occlusal, and posterior surfaces of "left rear teeth" of the corresponding upper jaw teeth row 98U or lower jaw teeth row 98L, the front and posterior surfaces of "front teeth", and the front, occlusal, and posterior surfaces of "right rear teeth". In addition, the symbol "-" in the body of Table 2 indicates that brushing is not possible. Angle of rotation within brackets ()Indicating that brushing is enabled, but the brushing steps are disengaged.

(Table 2) angle of rotation about longitudinal axisCorresponding relation with the anterior, posterior and occlusal surfaces

As shown in Table 2, the rotation angle about the longitudinal axis in the direction (+ Z direction) in which the brush staples 210 of the brush head part 4 faceIt is possible to determine which of the front, rear, and occlusal surfaces of the tooth rows 98U or 98L is brushed.

In this way, the control unit 110 can determine the direction (+ Z direction) in which the brush 210 of the brush head unit 4 faces around the longitudinal axis (Y axis) of the main body 1 as the rotation angle around the longitudinal axis based on the output of the acceleration sensor 15According to said angle of rotation about the longitudinal axisTo determine which of the front, rear, and occlusal surfaces of the teeth rows 98U or 98L is brushed.

Therefore, as described above, the control unit 110 can specify the brushing site BP in the tooth row 98U or 98L by using a combination of the translational position of the brushing site BP obtained from the output of the gyro sensor 16 and the determination result of which one of the front, rear, and occlusal surfaces of the tooth row 98U or 98L is brushed. This allows the tooth brushing part BP in the tooth row 98U or 98L to be specified with high accuracy.

Additionally, for left-handed users, it is preferable to replace the entire brushing step from the left to the right.

(correction processing)

In the brushing step described with reference to fig. 6, as indicated by arrows HCG1, HCG2, HCG3, and HCG4 in the figure, when the tooth row 98U or 98L moves from part SQ2 to part SQ3, from part SQ6 to part SQ7, from part SQ10 to part SQ11, and from part SQ14 to part SQ15, the orientation of the longitudinal axis (Y axis) of the main body 1 changes greatly from HR to HR from right to HR from right, respectively, while the translational movement of the brush head 4 is substantially stopped. As shown in fig. 16, regardless of the brushing step, the user may change the orientation of the longitudinal axis (Y axis) of the main body 1 from Y2 to Y3 largely as shown by an arrow MV1, for example, in a state where the translational movement of the brush head 4 is substantially stopped. As described above, when the orientation of the longitudinal axis (Y axis) of the main body 1 is changed greatly in a state where the translational movement of the brush head 4 is almost stopped, an error occurs in the process of step S2 shown in fig. 4 (the process of obtaining the translational position of the brushing part from the output of the gyro sensor 16).

Further, in some cases, the user during brushing the teeth may move the main body 1 in a large translational motion from the left buccal portion SQ1 to the right lingual portion SQ5 over the portion as indicated by arrow MV2 in the upper jaw teeth row 98U without substantially changing the orientation of the longitudinal axis (Y axis) of the main body 1, for example, as shown in fig. 17. As described above, when the body 1 is moved in translation by a large amount while skipping the site substantially without changing the orientation of the longitudinal axis (Y axis) of the body 1, an error occurs in the process of step S2 shown in fig. 4 (the process of obtaining the translational position of the brushing site from the output of the gyro sensor 16).

Therefore, in the present example, the control unit 110 performs the correction processing shown in the flow of fig. 18 while repeating the processing of steps S2 to S5 in fig. 4.

That is, as shown in step S41 of fig. 18, the control unit 110 calculates the amount of translational movement of the body 1 by performing second-order integration on the basis of the acceleration of the body 1 output from the acceleration sensor 15 for each 0.1 second serving as a unit period of processing. Here, the acceleration in the three-axis direction of the body 1 is represented by Acc _ X, Acc _ Y, Acc _ Z, the velocity in the three-axis direction is represented by v _ X, v _ Y, v _ Z, and the amount of translational movement of the body 1 in the three-axis direction is represented by D _ X, D _ Y, D _ Z. Then, the amount of translational movement Di of the main body 1 per processing unit period (where i is 1, 2, 3, and … …) is obtained by the following expressions (eq.7), (eq.8), and (eq.9).

v＿X＝∫(Acc＿X)dt

v＿Y＝∫(Acc＿Y)dt

v＿Z＝∫(Acc＿Z)dt

…(Eq.7)。

D＿X＝∫(v＿X)dt

D＿Y＝∫(v＿Y)dt

D＿Z＝∫(v＿Z)dt

…(Eq.8)。

Di＝(D_X)+(D_Y)+(D_Z)

…(Eq.9)。

Next, as shown in step S42, the control unit 110 sums the translational movement amounts Di of the main body 1 for each predetermined 0.5 second, which is a total unit period. Here, when the translational shift amounts Di per processing unit period are represented as D1, D2, D3, D4, and D5, respectively, the total translational shift amount D _ total for a certain total unit period is obtained by the following expression (eq.10).

D_total＝D1+D2+D3+D4+D5

…(Eq.10)。

Next, as shown in step S43, the control unit 110 determines whether or not the total translational movement amount D _ total is equal to or less than a predetermined first threshold value α 1 for a certain total unit period. In this example, α 1 is set to 20 mm. If D _ total is equal to or less than α 1 (yes in step S43), the process proceeds to step S44, and the controller 110 maintains the translational position of the brushing site BP determined from the output of the gyro sensor 16 for the total unit period (first correction process).

In such a case, for example, as shown in fig. 16, when the orientation of the vertical axis (Y axis) of the main body 1 is largely changed in a state where the user during brushing basically stops the translational movement of the main body 1 (particularly, the brush head part 4), the translational position of the brushing part BP obtained from the output of the gyro sensor 16 is maintained before and after the change. This can maintain the accuracy of the obtained translational position of the brushing site BP.

In the case where the tooth row is finer than the division in table 1, for example, in the case where each tooth is divided into two halves along the dental arch, the value of the first threshold α 1 is preferably set to be smaller, for example, 10mm or 5 mm.

On the other hand, in step S43 of fig. 18, if the total translational movement amount D _ total exceeds the first threshold value α 1 (no in step S43), the process proceeds to step S45, and the control unit 110 determines whether or not the total translational movement amount D _ total is equal to or greater than a predetermined second threshold value α 2 for the total unit period. In this example, α 2 is set to be larger than α 1, and α 2 is set to be 30 mm. Here, when D _ total is equal to or larger than α 2 (yes in step S45), the control unit 110 shifts to a portion corresponding to the translational movement destination of the main body 1 on the approximate curve E1 in the data space DS, and newly obtains the corresponding point P from the output of the gyro sensor 16 (second correction processing).

For example, as shown in fig. 17, when the body 1 is moved in a large translational motion by substantially changing the orientation of the vertical axis (Y axis) of the body 1, for example, skipping from the left buccal portion SQ1 to the right lingual portion SQ5 in the dentition 98U of the maxilla, the control unit 110 newly obtains the corresponding point P from the output (difference angle θ) of the gyro sensor 16 by shifting a point near + a from a point near the x coordinate of the approximation curve E1 in the data space DS shown in fig. 9.

In this case, the translational position of the brushing site BP in the tooth row 98U or 98L can be accurately obtained.

In this example, the second order integration is performed based on the output of the acceleration sensor 15 to calculate the amount of translational movement Di of the body 1 for each processing unit period. Therefore, the calculated total translational movement amount D _ total of the body 1 is affected by noise, and the accuracy is not high. However, there is no problem in using the calculated total translational movement amount D _ total of the main body 1 to determine whether the translational movement amount of the main body 1 (particularly, the brush head portion 4) is substantially zero (step S43 in fig. 18) or maximum (step S45 in fig. 18).

If α 1 < D _ total < α 2 (no in step S43 of fig. 18 and no in step S45 of fig. 18), control unit 110 determines that correction is not necessary and returns to the flow of fig. 4 (steps S2 to S5).

In the above example, in order to determine the translational position of the brushing site BP, an approximate curve E1 of "standard" which is a part of the ellipse E shown in fig. 7(a) is used. However, the present invention is not limited thereto. For a user having a "long" tooth row with a long depth and a narrow width as compared with a "standard" tooth row, for example, as shown in fig. 7(B), a portion having a depth D2 ≈ 60mm and a width W2 ≈ 60mm in an ellipse E ' with a short diameter 2a ' 60.43mm and a long diameter 2B ' 136.2mm may be used as the approximate curve E2. Further, for a user having a tooth row "small" compared with a tooth row "standard", as shown in fig. 7(C), a portion having a depth D3 ≈ 50mm and a width W3 ≈ 60mm in an ellipse E "with a short diameter 2a ≈ 62.21mm and a long diameter 2b ≈ 135.9mm may be used as the approximate curve E3. In this example, the selection of the "normal" approximation curve E1, the "vertical" approximation curve E2, or the "small" approximation curve E3 (including the setting of the short and long diameters) is executed by receiving the setting parameters from the outside of the main body 1 via the communication unit 180 as the receiving unit. In this case, the approximate curve can be appropriately set according to the size and shape of the dental arch of each user. This makes it possible to obtain the translational position of the brushing site BP in the tooth row with higher accuracy.

The actual brushing time data of each part and other data related to brushing acquired by the control unit 110 can be transmitted to the outside of the main body 1 through the communication unit 180 as a transmission unit. In this case, the data may be received by a computer device provided outside the main body 1, for example, and used for various processes and purposes.

(other approximation curves)

In the above-described embodiment, the dental arch of the subject in the real space RS is approximated by a curve (approximate curve E1, E2, or E3) in the data space DS that corresponds to a part of the ellipse E, but is not limited thereto.

As shown in fig. 19, the subject's dental arch in real space RS may also be approximated by a parabola U in data space DS. For convenience of explanation, the parabola U is tangent to the x-axis at the origin O (0, 0) in a convex manner.

Regarding a parabola U tangent to the x-axis in a convex form at the origin O (0, 0), p is expressed as a negative coefficient (i.e., p < 0)

4py＝x² …(Eq.11)。

Let a certain movable tangent line Q at point P (x)₁，y₁) Tangential to said parabola U. The equation of the movable tangent line Q is expressed by a mathematical formula

2p(y+y₁)＝xx₁ …(Eq.12)。

In addition, since the point P (x)₁，y₁) Is a point on the parabola U, the following equation holds.

4py₁＝x₁ ² …(Eq.13)。

Here, assuming that the inclination of the movable tangent line Q is m, the inclination is expressed by the equation (eq.12)

m＝x₁/2p …(Eq.14)。

Using equations (eq.13) and (eq.14), coordinate x of tangent point P for parabola U will be plotted₁、y₁When each is represented by a slope m, as shown below,

x₁＝2pm

y₁＝pm²

…(Eq.15)。

the inclination m is represented by "tan θ", where θ represents the angle formed by the movable tangent line Q and the x-axis (positive in the counterclockwise direction, -pi/2 ≦ theta ≦ pi/2). Then, the formula (eq.15) is as follows.

x₁＝2p(tanθ)

y₁＝p(tanθ)²

…(Eq.16)。

According to the equation (Eq.16) and the difference angle theta in the real space RS, the coordinate (x) of the corresponding point P corresponding to the tooth brushing part BP on the parabola U is obtained in the data space DS₁，y₁)。

In such a case, the approximation curve can be set by determining the coefficient p. Therefore, the process of obtaining the corresponding point P can be easily performed.

(System)

Fig. 20 illustrates the structure of a system (generally designated by reference numeral 700) incorporating the described electric toothbrush 90 and smartphone 600. The system 700 is provided with an electric toothbrush 90 and a smartphone 600 as a computer device, and the electric toothbrush 90 and the smartphone 600 can wirelessly communicate with each other via a network 900.

The smartphone 600 includes a main body 600M, and a control unit 610, a storage unit 620, an operation unit 630, a display 640, a communication unit 680, and a power supply unit 690 mounted on the main body 600M. The smartphone 600 is a commercially available smartphone on which application software described later is installed.

The control unit 610 includes a CPU and its auxiliary circuits, controls each unit of the smartphone 600, and executes processing in accordance with programs and data stored in the storage unit 620. For example, data input from the communication unit 680 is processed in accordance with an instruction input through the operation unit 630, and the processed data is stored in the storage unit 620, displayed on the display 640, or output through the communication unit 680.

The storage section 620 includes a ram (random Access memory) serving as a work area necessary for the control section 610 to execute the program, and a rom (read Only memory) for storing a basic program executed by the control section 610. As a storage medium of the auxiliary storage device that assists the storage area of the storage unit 620, a semiconductor memory (memory card, ssd (solid State drive)) or the like may be used.

In this example, the operation unit 630 is formed of a touch panel provided on the display 640. In addition, a keyboard and other hardware operating devices may be included.

In this example, the display 640 includes a display screen including an LCD (liquid crystal display element) or an organic EL (electroluminescence) display unit. The display 640 displays various images on a display screen according to the control of the control unit 610.

The communication unit 680 is configured to be able to perform wireless communication (for example, BT communication, BLE communication, or the like) with the electric toothbrush 90 via the network 900 in accordance with the control of the control unit 610.

In this example, the power supply unit 690 includes a rechargeable battery to supply power to the various units of the smartphone 600.

Assume that a user has pre-installed application software (referred to as a "power toothbrush program") in the smartphone 600. The electric toothbrush procedure is as follows: the smartphone 600 is wirelessly communicated with the electric toothbrush 90, various settings related to the tooth brushing procedure and the like are performed in the electric toothbrush 90, and data for specifying the tooth brushing part BP, the translational position (coordinate value) of the tooth brushing part, the direction in which the bristles 210 of the brush head 4 face, the output values of the gyro sensor and the acceleration sensor, and the like are received from the electric toothbrush 90 and used for various kinds of processing.

(setting of approximate Curve)

For example, the user starts the electric toothbrush program and selects the "electric toothbrush setting" mode via the operation unit 630. Then, the display 640 displays an "approximate curve setting" screen, and as selection candidates, an "standard" approximate curve E1 (a portion having a depth D1 ≈ 50mm and a width W1 ≈ 70mm in an ellipse E having a short diameter 2a ≈ 71.76mm and a long diameter 2b ≈ 128.2 mm), an "long" approximate curve E2 (a portion having a depth D2 ≈ 60mm and a width W2 ≈ 60mm in an ellipse E' having a short diameter 2a ═ 60.43mm and a long diameter 2b ≈ 136.2 mm), and a "small" approximate curve E3 (a portion having a depth D3 ≈ 50mm and a width W3 ≈ 60mm in an ellipse E "having a short diameter 2a ≈ 62.21mm and a long diameter 2b ≈ 135.9 mm) are displayed. When the user selects any one of the selection candidates via the operation unit 630, the electric toothbrush 90 sets the selected approximate curve.

The short diameter and the long diameter of the selected ellipse and the size (depth and width) of the portion of the selected ellipse used as the approximate curve may be variably set on the screen of the display 640 in continuous values.

In the case of using the parabola U as the approximate curve, the coefficient p is preferably set to be variable.

(evaluation of tooth brushing)

In the brushing step described with reference to fig. 6, the teeth are brushed from portions SQ1 to SQ8 in the dentition 98U of the upper jaw, and then from portions SQ9 to SQ16 in the dentition 98L of the lower jaw in the order of increasing numbers. Further, in the brushing step, as exemplified in table 3 below, when brushing the teeth at each of the sites SQ1 to SQ16, the sites SQ1 to SQ16 are each brushed with a predetermined brushing setting period. For example, the brushing setting period is set as follows: in the dentition 98U of the maxilla, 8 seconds are assigned to the position SQ1, 4 seconds are assigned to the position SQ2, and 9 seconds, … … are assigned to the position SQ 3. Further, the brushing setting period is set as follows: in the dentition 98L of the mandible, 5 seconds were spent for position SQ9, 5 seconds for position SQ10, and 7 seconds, … … for position SQ 11.

(Table 3)

As described with respect to step S8 of fig. 4, the actual brushing time data for each part is recorded in the table prepared in the storage unit 115 by associating the specific brushing part BP with the actual brushing time for the part BP. In this example, as shown in Table 3, the actual brushing time is as follows: in the dentition 98U of the palate, 7.2 seconds for position SQ1, 3.7 seconds for position SQ2, and 6.9 seconds, … … for position SQ 3. Further, the actual brushing time is a value as follows: in the dentition 98L of the chin, 5 seconds were spent for part SQ9, 4.6 seconds were spent for part SQ10, and 6.6 seconds, … … were spent for part SQ 11.

In this example, the control unit 610 of the smartphone 600 receives data (including actual brushing time data for each part) recorded in the table of the storage unit 115 from the electric toothbrush 90 via the communication unit 680. The controller 610 operates as a brushing evaluation unit, and calculates an evaluation value (brushing evaluation value) indicating the degree of matching with the brushing procedure, based on the actual brushing time data for each site.

Specifically, the tooth brushing evaluation value (unit%) for each of the regions SQ1 to SQ16 is calculated from the following expression.

(brushing evaluation value) × 100 × (actual brushing time (sec))/(brushing setting period (sec))

In the data example of table 3, the brushing evaluation values are as follows: in the upper jaw teeth row 98U, the number of regions SQ1 is 90%, SQ2 is 93%, and SQ3 is 77%, … …. Further, the brushing evaluation value is a value as follows: in the tooth row 98L of the lower jaw, the number of regions SQ9 was 100%, SQ10 was 92%, SQ11 was 94%, … ….

In this example, the control unit 610 of the smartphone 600 displays the brushing evaluation value on the display screen of the display 640. Thus, the user can know the degree of conformity or nonconformity of the brushing style with the brushing procedure by observing the display screen of the display 640. In particular, it is found that the brushing of the teeth by itself is not consistent with the above-described brushing procedure, and for example, the brushing of the teeth at the rear of the left rear tooth (position SQ7) and the rear of the right rear tooth (position SQ5) is insufficient in the dentition 98U of the upper jaw. Therefore, the user can improve the brushing manner of the user.

In the above embodiment, the controller 110 of the electric toothbrush 90 performs the function of the brushing site detector, but is not limited thereto. While the electric toothbrush 90 and the smartphone 600 are communicating with each other during brushing, the controller 610 of the smartphone 600 may execute a part or all of the functions of the brushing site detector. In this case, the configuration of the control unit 110 of the electric toothbrush 90 can be simplified. Thus, the control unit 110 may be formed of, for example, a logic IC (integrated circuit) instead of the CPU.

For example, the controller 110 of the electric toothbrush 90 may perform basic determination of the brushing site BP in the function of the brushing site detector (the flow of fig. 4, particularly, steps S2 and S3), while the controller 610 of the smartphone 600 may perform correction processing (the flow of fig. 18). This can distribute the processing load between the electric toothbrush 90 and the smartphone 600.

In order to constitute a system combined with the electric toothbrush 90, a device that substantially functions as a computer device, such as a tablet terminal, a personal computer, or the like, may be employed instead of the smartphone 600.

The processing method executed by the control unit 110 of the electric toothbrush 90 or the control unit 610 of the smartphone 600 may be recorded as application software (computer program) in a non-transitory (non-transitory) storage medium such as a CD (compact disc), a DVD (digital versatile disc), or a flash memory. By installing application software recorded in such a storage medium to a substantial computer device such as a personal computer, a PDA (personal digital assistant), a smart phone, or the like, it is possible to cause the computer device to execute the method.

In addition, when the dental arch of the user is inclined with respect to the horizontal plane, an xyz rectangular coordinate system may be set in the data space, and an approximate curve inclined with respect to the horizontal xy plane may be set. This allows the dental arch of the user to be approximated with an approximation curve with high accuracy. Therefore, the translational position of the brushing part in the tooth row can be accurately obtained.

The above embodiments are merely illustrative, and various modifications may be made without departing from the scope of the present invention. Although the above-described embodiments can be individually established, the embodiments can be combined with each other. Further, although the various features in the different embodiments can be individually established, the features in the different embodiments can be combined with each other.