Patent Publication Number: US-2019167941-A1

Title: Drowsiness eliminating device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a United States national stage application of International Application No. PCT/JP2017/028258, filed Aug. 3, 2017, which designates the United States, and claims priority to Japanese Patent Application No. 2016-158434, filed Aug. 12, 2016, and the entire contents of each of the above applications are hereby incorporated herein by reference in entirety. 
    
    
     BACKGROUND 
     Technical Field 
     This application relates to a drowsiness eliminating device. 
     Background Art 
     As one type of drowsiness eliminating devices, a drowsiness eliminating device disclosed in Patent Literature 1 has been known. As shown in FIG. 2 of the Patent Literature 1, the drowsiness eliminating device includes a danger detecting means which includes a vehicle lane deviating predicting and detecting means and/or a driver drowsiness detecting means and an alarm motor control means which generates an alarm vibration to an electric seat by rotating a motor in normal/reverse directions which operates the electric motor, by outputting normal/reverse rotation signal upon receipt of a detecting signal from the danger detecting means. Thus, the drowsiness eliminating device generates an alarm to the driver of the vehicle by vibration, utilizing a motor which is prepared in advance for operating each part of the electric seat. 
     Further, as another type of the drowsiness eliminating devices, a drowsiness eliminating device disclosed in Patent Literature 2 has been known. As shown in FIG. 1 of the Patent Literature 2, according to the drowsiness eliminating device disclosed therein, when a driver D becomes drowsy, the air bag  3  expands and imparts a pressing stimulus (baresthesia) as an awakening stimulus to the driver D&#39;s  musculus  erector spinae and the biomedical measurement device  8  measures the muscle potential as a parameter indicating the activity state of the  musculus  erector spinae. Then, a wakening state maintaining ECU  11  controls the strength of the baresthesia which is the awakening stimulus to be imparted to the  musculus  erector spinae by the air bag  3  based on the measured muscle potential to a level that the brain cell of the driver D is activated. In addition, the drowsiness eliminating device is configured such that the vibration body  7  imparts vibration stimulus to the  musculus  erector spinae. 
     RELATED ART LITERATURE 
     Patent Literature 
     Patent Literature 1 JP 2008-260444 A 
     Patent Literature 2 JP2010-172541 A 
     SUMMARY 
     Technical Problem(S) 
     According to the drowsiness eliminating device disclosed in the Patent Literature 1, a vibration is applied to the electric seat and the vibration is used as an alarm to the driver of the vehicle to be able to inform the driver of a danger. However, it is not sufficient for the driver of the vehicle to eliminate drowsiness, merely informing the driver of the danger. 
     Further, according to the drowsiness eliminating device disclosed in the Patent Literature 2, the air bag  3  expands and imparts baresthesia stimulus which is the awakening stimulus to the driver D&#39;s  musculus  erector spinae to thereby impart stimulus to the driver D. However, the part of the body to which the stimulus is imparted in this drowsiness eliminating device is not a proper portion and the driver would not sufficiently eliminate the drowsiness. 
     The present application has been made to eliminate the aforementioned problem and the objective of the application is to provide a drowsiness eliminating device which can impart stimulus to a part where more awakening effect can be achieved. 
     Solution to Problem(S) 
     In order to solve the above problem(s), the drowsiness eliminating device according to an aspect of the application includes at least one of a first stimulus imparting device group including a first stimulus imparting device provided on a chair such that the tendon of latissimus dorsi of a user of the chair faces when the user sits on the chair and imparting a stimulus to the tendon of latissimus dorsi of the user and a second stimulus imparting device provided on the chair facing a first skin portion when the user sits on the chair and imparting the stimulus to the first skin portion of the user which is a skin part covering a skeletal muscle which is associated with a first motion illusion induced at a supplementary motor area activated by the stimulus to the tendon of latissimus dorsi and which is a cooperative muscle of the latissimus dorsi and a second stimulus imparting device group including a third stimulus imparting device provided on the chair such that the tendon of gluteus medius muscle of the user of the chair faces when the user sits on the chair and imparting a stimulus to the tendon of gluteus medius muscle of the user and a fourth stimulus imparting device provided on the chair facing a second skin portion when the user sits on the chair and imparting the stimulus to the second skin portion of the user which is a skin part covering a skeletal muscle which is associated with a second motion illusion induced at a supplementary motor area activated by the stimulus to the tendon of gluteus medius muscle and which is a cooperative muscle of the gluteus medius muscle and a drive control device which includes a driving control portion which drive-controls said at least one of the first stimulus imparting device group and the second stimulus imparting device group to impart stimulus to the user of the chair. 
     According to such a configuration, the drive control device imparts stimulus to the tendon of latissimus dorsi of the user by the first stimulus imparting device and to the first skin portion of the user by the second stimulus imparting device, and/or the drive control device imparts stimulus to the tendon of gluteus medius muscle of the user by the third stimulus imparting device and to the second skin portion of the user by the fourth stimulus imparting device. Accordingly, in addition to properly stimulating tendon of latissimus dorsi and/or gluteus medius muscle which are the parts highly effective to awaken the user, it is possible to properly stimulate a first skin portion which is a skin part covering the skeletal muscle that is a cooperative muscle of the latissimus dorsi of the user of the chair which is associated with a first motion illusion which is induced at the supplementary motor area activated by the stimulus to the tendon of latissimus dorsi and/or properly stimulate a second skin portion which is a skin part covering the skeletal muscle that is a cooperative muscle of the gluteus medius muscle of the user which is associated with a second motion illusion which is induced at the supplementary motor area activated by the stimulus to the tendon of gluteus medius muscle. Thus, by simulating two portions which awakening effects are mutually correlated to thereby achieve a higher awakening effect. Accordingly, the drowsiness eliminating device can properly stimulate the portions where the awakening effect is high. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view showing a concept of a first embodiment of a drowsiness eliminating device according to the present application; 
         FIG. 2  is an upper plan view showing the drowsiness eliminating device indicated in  FIG. 1  and indicating a state that the vibration portion of the drowsiness eliminating device is stored; 
         FIG. 3  is an upper plan view showing the drowsiness eliminating device indicated in  FIG. 1  and indicating a state that the vibration portion of the drowsiness eliminating device is in contact with the user; 
         FIG. 4  is a view showing a drowsiness generation suppression effect of various types of skeletal muscles; 
         FIG. 5  is a view showing the drowsiness generation suppression effect of tendon portion and the abdominal part of the same skeletal muscle; 
         FIG. 6  is a correlation of the nerve activity value of the supplementary motor area and the drowsiness eliminating effect; 
         FIG. 7  shows a bar chart at left side showing the nerve activity value of the supplementary motor area when only the gluteus medius muscle is stimulated with a predetermined stimulus, whereas a bar chart at the right side showing the nerve activity value of the supplementary motor area when both of the gluteus medius muscle and the femur outside portion which corresponds to the second skin portion are stimulated with a predetermined stimulus; 
         FIG. 8  is a block diagram indicating the control device shown in  FIG. 1 ; 
         FIG. 9  is a view indicating a drowsiness generation suppression effect per frequency of vibration stimulus; 
         FIG. 10  is a view indicating a drowsiness generation suppression effect per time of imparting vibration stimulus; 
         FIG. 11  is a view indicating a drowsiness eliminating effect when a vibration stimulus is imparted to the latissimus dorsi; 
         FIG. 12  is a view indicating a drowsiness eliminating effect when a vibration stimulus is imparted to the gluteus medius muscle; 
         FIG. 13  is a view indicating the drowsiness eliminating effect when a vibration stimulus is imparted to only the tendon of the gluteus medius muscle; 
         FIG. 14  is a view indicating a drowsiness eliminating effect when a vibration stimulus is imparted to both of the tendon of the gluteus medius muscle and the skin portion (second skin portion) of femur outside portion; 
         FIG. 15  is a view indicating a drowsiness eliminating effect when a vibration stimulus is imparted to only the skin portion (second skin portion) of femur outside portion; 
         FIG. 16  is a flowchart of a control program which is executed by the control device shown in  FIG. 1 ; and 
         FIG. 17  is a schematic view showing an outline of the drowsiness eliminating device according to the second embodiment of the application. 
     
    
    
     DETAILED DESCRIPTION 
     First Embodiment 
     Hereinafter, a first embodiment of a drowsiness eliminating device according to the present application will be explained. As shown in  FIG. 1 , a drowsiness eliminating device  10  is installed in a vehicle A. The drowsiness eliminating device  10  is provided at a vehicle seat  20  that is a driver&#39;s seat of the vehicle A. The vehicle seat  20  is a chair on which the driver M sits as a user. The vehicle seat  20  includes a seat cushion  21  and a seat back  22 . 
     The drowsiness eliminating device  10  includes, as shown in  FIGS. 1 and 2 , a main body  11 , a first stimulus imparting device group  12  provided at the main body  11 , a second stimulus imparting device group  13  provided at the main body  11  and a control device  40  which controls the first stimulus imparting device group  12  and the second stimulus imparting device group  13 . 
     It is noted here that the control device  40  may be installed at the vehicle body side (for example, on the vehicle seat  20  or vehicle frame, etc.). Still further, the control device  40  may be stored in the main body  11 . 
     The main body  11  is formed separately from the vehicle seat  20  and can be detachably assembled with the vehicle seat  20 . The main body  11  is formed in shape of a bucket seat for the driver M free to be seated. The bucket seat shape is shaped such that the height of the right and left ends thereof is formed extremely high compared to a normal type of vehicle seat so as to deeply embrace the femur, hips, and shoulder of the driver M. The main body  11  is structured to cover or shroud the flank, waist, and femur of the body side of the driver M (user). 
     The first stimulus imparting device group  12  includes a first stimulus imparting device  14  and a second stimulus imparting device  15 . The first stimulus imparting device group  12  includes a right side first stimulus imparting device group  12 R which is arranged at the right side and a left side first stimulus imparting device group  12 L arranged at the left side. The right side first stimulus imparting device group  12 R includes a right side first stimulus imparting device  14 R and a right side second stimulus imparting device  15 R. The left side first stimulus imparting device group  12 L includes a left side first stimulus imparting device  14 L and a left side second stimulus imparting device  15 L. 
     The first stimulus imparting device  14  is provided at the main body  11  and serves as a device which imparts stimulus to the tendon of the latissimus dorsi of the driver M. The first stimulus imparting device  14  is provided at the vehicle seat  20  via the main body  11 . The first stimulus imparting device  14  includes the right side first stimulus imparting device (right side latissimus dorsi stimulus imparting device)  14 R which imparts stimulus to the right side latissimus dorsi and the left side first stimulus imparting device (left side latissimus dorsi stimulus imparting device)  14 L which imparts stimulus to the left side latissimus dorsi. It is preferable to arrange the right side first stimulus imparting device  14 R in the vicinity of a portion of the main body  11  facing the right side tendon M 1 R of the latissimus dorsi of the driver M when the driver M is seated on the main body  11 . It is also preferable to arrange the left side first stimulus imparting device  14 L in the vicinity of a portion of the main body  11  facing the left side tendon M 1 L of the latissimus dorsi of the driver M when the driver M is seated on the main body  11 . 
     The second stimulus imparting device  15  is provided at the main body  11  and serves as a device which imparts stimulus to the first skin portion of the driver M. The first skin portion is a skin part covering the skeletal muscle associated with a first motion illusion which is induced at the supplementary motor area (a portion of brain) activated by the stimulus to the tendon of latissimus dorsi and which is a cooperative muscle of the latissimus dorsi. In more detail, the first motion illusion is a motion illusion that the arm moves upward and the first skin potion is a skin portion (skin portion located in the vicinity of skeletal muscle (for example, serratus anterior muscle) which covers skeletal muscle (for example, serratus anterior muscle) associated with the first motion illusion and is a cooperative muscle of the latissimus dorsi. The first skin portion is a skin area, for example, from the inferior angle of scapula to the armpit portion. It is noted that the “cooperative muscle” is a muscle which helps the work of protagonist muscle that is the main muscle for action, when a human makes a motion. 
     In the motion that the arm moves downward (contract of latissimus dorsi), the latissimus dorsi works as the protagonist muscle and the serratus anterior muscle works as the cooperative muscle. When a stimulus (for example, vibration stimulus) is imparted to the tendon of latissimus dorsi, the activity of muscle spindle becomes high and such information is transmitted to the centrum system (brain) and accompanied by this activity, the motion illusion (first motion illusion) is induced. The information from the muscle spindle is the information that “the muscle is expanded” and this is erroneously recognized (illusion) that the latissimus dorsi is expanding, i.e., the arm is moving upward. On the other hand, when the arm is actually moved upward, the latissimus dorsi is expanded and the skin in the vicinity thereof (skin portion covering the cooperative muscle) also expands and such expansion information is transmitted to the centrum. On the contrary, when a stimulus is imparted to the latissimus dorsi, since the arm is not actually moving (illusion only), the information from the skin portion covering the cooperative muscle is not transmitted to the centrum by the stimulus imparted only to the tendon of latissimus dorsi. Therefore, in addition to the stimulus to the tendon of latissimus dorsi, by imparting the stimulus to the skin portion associated with the motion illusion, the motion illusion (activity of supplementary motor area) can be heightened. Thus, the tendon of latissimus dorsi and the skin portion which covers the serratus anterior muscle as the cooperative muscle of latissimus dorsi are two parts correlated in the first motion illusion. 
     The second stimulus imparting device  15  is provided at the vehicle seat  20  via the main body  11 . The second stimulus imparting device  15  includes the right side second stimulus imparting device (right side first skin portion stimulus imparting device)  15 R which imparts stimulus to the right side first skin portion and the left side second stimulus imparting device (left side first skin portion stimulus imparting device)  15 L which imparts stimulus to the left side first skin portion. It is preferable to arrange the right side second stimulus imparting device  15 R in the vicinity of a portion of the main body  11  facing the right side first skin portion M 2 R of the driver M when the driver M is seated on the main body  11 . It is also preferable to arrange the left side second stimulus imparting device  15 L in the vicinity of a portion of the main body  11  facing the left side first skin portion M 2 L of the driver M when the driver M is seated on the main body  11 . 
     The second stimulus imparting device group  13  includes a third stimulus imparting device  16  and a fourth stimulus imparting device  17 . The second stimulus imparting device group  13  includes a right side second stimulus imparting device group  13 R which is arranged at the right side and a left side second stimulus imparting device group  13 L arranged at the left side. The right side second stimulus imparting device group  13 R includes a right side third stimulus imparting device  16 R and a right side fourth stimulus imparting device  17 R. The left side second stimulus imparting device group  13 L includes a left side third stimulus imparting device  16 L and a left side fourth stimulus imparting device  17 L. 
     The third stimulus imparting device  16  is provided at the main body  11  and serves as a device which imparts stimulus to the tendon of the gluteus medius muscle of the driver M. The third stimulus imparting device  16  is provided at the vehicle seat  20  via the main body  11 . The third stimulus imparting device  16  includes the right side third stimulus imparting device (right side gluteus medius muscle stimulus imparting device)  16 R which imparts stimulus to the right side gluteus medius muscle and the left side third stimulus imparting device (left side gluteus medius muscle stimulus imparting device)  16 L which imparts stimulus to the left side gluteus medius muscle. It is preferable to arrange the right side third stimulus imparting device  16 R in the vicinity of a portion of the main body  11  facing the right side tendon M 3 R of the gluteus medius muscle of the driver M when the driver M is seated on the main body  11 . It is also preferable to arrange the left side third stimulus imparting device  16 L in the vicinity of a portion of the main body  11  facing the left side tendon M 3 L of the gluteus medius muscle of the driver M when the driver M is seated on the main body  11 . 
     The fourth stimulus imparting device  17  is provided at the main body  11  and serves as a device which imparts stimulus to the second skin portion of the driver M. The second skin portion is a skin part that covers the skeletal muscle that is associated with the second motion illusion induced at the supplementary motor area (a part of brain) activated by the stimulus imparted to the tendon of the gluteus medius muscle and is a cooperative muscle of the gluteus medius muscle. In more detail, the second motion illusion is an illusion that the femur portion moves inner side and the second skin potion is a skin part (skin part in the vicinity of skeletal muscle, for example, vastus lateralis that is a cooperative muscle of the gluteus medius muscle) covering the skeletal muscle that is associated with a second motion illusion and which is a cooperative muscle of the gluteus medius muscle. The second skin portion is a skin area for example, femur outside portions. 
     In the motion that the femur portion moves outward (contract of gluteus medius muscle), the gluteus medius muscle works as the protagonist muscle and the vastus lateralis muscle works as the cooperative muscle. When a stimulus (for example, vibration stimulus) is imparted to the tendon of gluteus medius muscle, the activity of muscle spindle becomes high and such information is transmitted to the centrum system (brain) and accompanied by this activity, the motion illusion (second motion illusion) is induced. The information from the muscle spindle is the information that “the muscle is expanded” and this is erroneously recognized (illusion) that the gluteus medius muscle is expanded, i.e., the femur portion is moved inner side. On the other hand, when the femur portion is actually moved inward, the gluteus medius muscle is expanded and the skin in the vicinity thereof (skin portion covering the cooperative muscle) also expands and such expansion information is transmitted to the centrum. On the contrary, when a stimulus is imparted to the gluteus medius muscle, since the femur portion is not actually moving (illusion only), the information from the skin portion covering the cooperative muscle is not transmitted to the centrum by the stimulus imparted only to the tendon of gluteus medius muscle. Therefore, in addition to imparting stimulus to the tendon of gluteus medius muscle, by imparting the stimulus to the skin portion associated with the motion illusion, the motion illusion (activity of supplementary motor area) can be heightened. Thus, the tendon of gluteus medius muscle and the skin portion which covers the vastus lateralis muscle as the cooperative muscle of the gluteus medius muscle are two parts correlated in the second motion illusion. 
     The fourth stimulus imparting device  17  is provided at the vehicle seat  20  via the main body  11 . The fourth stimulus imparting device  17  includes the right side fourth stimulus imparting device (right side second skin portion stimulus imparting device)  17 R which imparts stimulus to the right side second skin portion and the left side fourth stimulus imparting device (left side second skin portion stimulus imparting device)  17 L which imparts stimulus to the left side second skin portion. It is preferable to arrange the right side fourth stimulus imparting device  17 R in the vicinity of a portion of the main body  11  facing the right side second skin portion M 4 R of the driver M when the driver M is seated on the main body  11 . It is also preferable to arrange the left side fourth stimulus imparting device  17 L in the vicinity of a portion of the main body  11  facing the left side second skin portion M 4 L of the driver M when the driver M is seated on the main body  11 . 
     The right side first stimulus imparting device  14 R includes, as shown in  FIGS. 2 and 3 , a vibration portion  14 R 1  which imparts stimulus (vibration) to the tendon M 1 R of the right side latissimus dorsi by contacting therewith and a moving portion  14 R 2  which moves the vibration portion  14 R 1  in advancing and retreating directions relative to the driver M. The base portion of the moving portion  14 R 2  is fixed to the main body  11  and the tip end of the moving portion  14 R 2  is fixed to the vibration portion  14 R 1 . The vibration portion  14 R 1  stores a motor therein (not shown) and is configured to generate a vibration by converting the rotational movement of the motor into the linear motion. It is noted that the vibration portion  14 R 1  may be configured to house a linear motor therein to generate a vibration by the linear motion of the output shaft of the motor. The moving portion  14 R 2  may be configured to be an air bag type which contracts or expands in response to the supply or discharge of the air from an air pump, or may be configured to be a combination of link mechanism and motor. 
     Similar to the right side first stimulus imparting device  14 R, the left side first stimulus imparting device  14 L includes a vibration portion  14 L 1  which imparts stimulus (vibration) to the tendon M 1 L of the left side latissimus dorsi by contacting therewith and a moving portion  14 L 2  which moves the vibration portion  14 L 1  in advancing and retreating directions. 
     Similar to the right side first stimulus imparting device  14 R, the right side second stimulus imparting device  15 R includes a vibration portion  15 R 1  which imparts stimulus (vibration) to the right side first skin portion M 2 R by contacting therewith and a moving portion  15 R 2  which moves the vibration portion  15 R 1  in advancing and retreating directions. 
     Similar to the right side first stimulus imparting device  14 R, the left side second stimulus imparting device  15 L includes a vibration portion  15 L 1  which imparts stimulus (vibration) to the left side first skin portion M 2 L by contacting therewith and a moving portion  15 L 2  which moves the vibration portion  15 L 1  in advancing and retreating directions. 
     Similar to the right side first stimulus imparting device  14 R, the right side third stimulus imparting device  16 R includes a vibration portion  16 R 1  which imparts stimulus (vibration) to the right side tendon M 3 R of gluteus medius muscle by contacting therewith and a moving portion  16 R 2  which moves the vibration portion  16 R 1  in advancing and retreating directions. Similar to the right side first stimulus imparting device  14 R, the left side third stimulus imparting device  16 L includes a vibration portion  16 L 1  which imparts stimulus (vibration) to the left side tendon M 3 L of gluteus medius muscle by contacting therewith and a moving portion  16 L 2  which moves the vibration portion  16 L 1  in advancing and retreating directions. 
     Similar to the right side first stimulus imparting device  14 R, the right side fourth stimulus imparting device  17 R includes a vibration portion  17 R 1  which imparts stimulus (vibration) to the right side second skin portion M 4 R by contacting therewith and a moving portion  17 R 2  which moves the vibration portion  17 R 1  in advancing and retreating directions. 
     Similar to the right side first stimulus imparting device  14 R, the left side fourth stimulus imparting device  17 L includes a vibration portion  17 L 1  which imparts stimulus to the left side second skin portion M 4 L by contacting therewith and a moving portion  17 L 2  which moves the vibration portion  17 L 1  in advancing and retreating directions. 
     It is noted that the drowsiness eliminating device  10  may be configured to be housed in the vehicle seat  20 . 
     Further, the strength (magnitude) of stimulus imparted by the second stimulus imparting device  15  may be preferably set to be smaller than the strength of the stimulus imparted by the first stimulus imparting device  14 . The strength (magnitude) of stimulus imparted by the fourth stimulus imparting device  17  may be preferably set to be smaller than the strength of the stimulus imparted by the third stimulus imparting device  16 . 
     The reason why the stimulus is imparted to a particular portion (i.e., the tendon of latissimus dorsi or tendon of gluteus medius muscle) will be explained hereinafter. The inventors of the application found by experimental work that a tendon of a particular skeletal muscle (including muscle tendon junction) has a high awakening effect. Such particular skeletal muscle is the tendon of latissimus dorsi and tendon of gluteus medius muscle.  FIG. 4  indicates an experimental result that a vibration stimulus is imparted to a plurality of tendons of skeletal muscles when a person in test is at a first drowsiness level where the person does not feel drowsy. The horizontal axis indicates the time between the imparting stimulus is started and a certain time period passed therefrom and the vertical axis indicates the level of drowsiness. 
     The vibration stimulus is the same stimulus that is continuously imparted for thirty seconds with the frequency of 100 Hz. The drowsiness level is measured by changing the skeletal muscle of the person in test to which the stimulus is imparted. The drowsiness level is defined by self-assessment of the subject person or may be defined by measurement. The white square indicates the change of drowsiness level when the stimulus is imparted to the origin side tendon of gluteus medius muscle, the diamond indicates the change of drowsiness level when the stimulus is imparted to the origin side tendon of hamstrings, the circle indicates the change of drowsiness level when the stimulus is imparted to the origin side (rib) tendon of upper side fiber latissimus dorsi and the triangle indicates change of drowsiness level when the stimulus is imparted to the origin side tendon of top side trapezius muscle. It is noted that the hamstrings is a collective name of muscles at lower limbs back side, such as biceps femoris, semimembranosus muscle and semitendinosus, etc. 
     Apparent from the experimental result, in the hamstrings and the trapezius muscle, the drowsiness level becomes great to the drowsiness side from the early timing. On the contrary, in the latissimus dorsi and tendon of gluteus medius muscle, the first drowsiness level that is the non-drowsy level is maintained for a relatively long time period. Accordingly, the drowsiness suppression effect is high at the latissimus dorsi and tendon of gluteus medius muscle, i.e., a high awakening effect can be maintained thereby. 
     It is noted that a muscle spindle exists in the skeletal muscle. The muscle spindle serves as a sensor which senses the state of muscle and the information that the muscle spindle is being activated is transmitted to the brain stem reticular formation to raise the activity level of the brain (awakening level is raised). Further, it is noted that the latissimus dorsi and tendon of gluteus medius muscle are the “type I” fiber which includes many muscle spindles and are arranged such that a plurality of skeletal muscles are not overlapped one another. Accordingly, each of these portions is not influenced by another skeletal muscle which responsiveness is different. Thus, a stable effect can be achieved thereby. 
     Further, the inventors found by experimental work that among the latissimus dorsi and gluteus medius muscle, the tendon portion is more effective than the abdominis muscle portion.  FIG. 5  indicates the experimental work result that a vibration stimulus is imparted to the latissimus dorsi and tendon of gluteus medius muscle of the same skeletal muscle when a person in test is at a first drowsiness level where the person does not feel drowsy. The horizontal axis indicates the time between the imparting stimulus is started and a certain time period passed therefrom and the vertical axis indicates the level of drowsiness. 
     The vibration stimulus is the same stimulus that is continuously imparted for thirty seconds with the frequency of 100 Hz. The drowsiness level is measured by changing the skeletal muscles of the person in test to which the stimulus is imparted. The drowsiness level is defined by self-assessment of the subject person or may be defined by measurement. The white square indicates the change of drowsiness level when the stimulus is imparted to the abdominis muscle portion of upper side fiber latissimus dorsi muscle and the circle indicates the change of drowsiness level when the stimulus is imparted to the origin side (rib) tendon of upper side fiber latissimus dorsi. 
     Apparent from the experimental result, in the abdominis muscle portion, the drowsiness level becomes great to the drowsiness side from the early timing. To this, in the origin side tendon, the first drowsiness level that is the non-drowsy level is maintained for a relatively long time period. Accordingly, the drowsiness generation suppression effect is high at the tendon portion, i.e., a high awakening effect can be maintained. 
     Further, the inventors of the application found that the awakening effect is higher in the case where the stimulus is imparted to the first skin portion and the second skin portion in addition to the imparting the stimulus to the tendon of latissimus dorsi and tendon of gluteus medius muscle, than in the case where the stimulus is only imparted to the tendon of latissimus dorsi and tendon of gluteus medius muscle. 
     As explained above, when the stimulus is imparted to the tendon of latissimus dorsi and tendon of gluteus medius muscle, the muscle spindle is activated to activate the supplementary motor area. Under this state, the motion illusion has been induced in the brain. Further, a nerve projection is projected to the brain stem reticular formation which is associated with the brain awakening from the supplementary motor area and thus the activity of the supplementary motor area heightens the stimulus to the brain stem reticular formation. Thus, the drowsiness can be eliminated. As shown in  FIG. 6 , the larger the nerve activity value of the supplementary motor area, the higher the drowsiness eliminating effect becomes. In other words, the stronger the supplementary motor area is activated, the higher the drowsiness eliminating effect becomes. 
     On the other hand, as explained above, there is a close correlation between the activity of the supplementary motor area and the induction of the motion illusion corresponding to the supplementary motor area. In other words, the larger the degree of induction of the motion illusion corresponding to the supplementary motor area, the higher the drowsiness eliminating effect becomes. Further, the stronger the supplementary motor area is activated and at the same time the larger the degree of induction of the motion illusion corresponding to the supplementary motor area, the higher the drowsiness eliminating effect becomes. The reason is that since the supplementary motor area is strongly activated, more effective drowsiness eliminating effect can be achieved. 
     This can be apparent from the experimental data shown in  FIG. 7 . The bar graph at the left side of the drawing indicates the nerve activity value of the supplementary motor area when only the tendon portion of the gluteus medius muscle receives a predetermined stimulus. The bar graph at the right side of the drawing indicates the nerve activity value of the supplementary motor area when both tendon portion of the gluteus medius muscle and the femur outside portions that correspond to the second skin portion, receive a predetermined stimulus. As apparent from  FIG. 7 , the nerve activity value of the supplementary motor area becomes increased when both tendon portion of the gluteus medius muscle and femur outside portions that correspond to the second skin portion, receive a predetermined stimulus, compared to the case when only the tendon portion of the gluteus medius muscle receives a predetermined stimulus. Since the supplementary motor area is strongly activated, more effective drowsiness eliminating effect can be achieved. 
     As shown in  FIG. 8 , the driver monitor  31 , the selection switch  32  and the stimulus imparting switch  33  are electrically connected to the control device  40 . 
     The driver monitor  31  is installed in the vehicle A at the inside thereof (such as dashboard, or rearview mirror), as shown in  FIG. 1 . The driver monitor  31  serves as a device for watching the driver M and is formed by, for example, a camera, etc. The driver monitor  31  detects whether the driver M is drowsy or not from the facial expression of the driver M which expression is image-taken by the camera. For example, when the increase of the number of yawning, the increase (or decrease) of the number of blinking or a closing state of eyelid is recognized, the driver monitor  31  detects that the drowsiness exists. The detection result is outputted to the control device  40 . It is noted here that in regard to the driver monitor  31 , it may be configured such that the camera in the driver monitor  31  takes the image of the driver M and the expression information of the driver&#39;s image is outputted to the control device  40  and the control device  40  judges whether the driver M is drowsy or not based on the expression information. 
     The selection switch  32  is a switch used for selecting whether a support for eliminating drowsiness is necessary or not and the selection result is outputted to the control device  40 . The support for eliminating drowsiness is a control which eliminates the drowsiness by imparting a stimulus to the driver M when the driver M feels drowsy (the third drowsiness level). 
     The drowsiness level is set to four stage levels, the first drowsiness level which is a non-drowsy level, the second drowsiness level which is slightly drowsy level, the third drowsiness level which is a drowsy level and the fourth drowsiness level which is a very drowsy level. 
     The stimulus imparting switch  33  is a switch for imparting a stimulus to the driver M on the request by the driver M. The state of ON/OFF of the switch  33  is outputted to the control device  40 . When the stimulus imparting switch  33  is turned ON, each of the stimulus imparting device groups  12 R,  12 L,  13 R and  13 L is driven to impart the stimulus to the driver M with a predetermined stimulus pattern. It may be configured that a stimulus is imparted to the driver M each time the stimulus imparting switch  33  is turned ON. Alternatively, it may be configured that a stimulus is imparted to the driver M per every predetermined time period while the stimulus imparting switch  33  is being turned ON. 
     The control device  40  includes, as shown in  FIG. 8 , a switch state obtaining/judging portion  41 , a drowsiness eliminating judging portion  42 , each stimulus pattern determining portion  43   a ,  43   b  and a driving control portion  44 . 
     When the selection switch  32  selects any one of the drowsiness generation suppression support, the drowsiness eliminating support or non-selection state, the switch state obtaining/judging portion  41  obtains the selection result from the selection switch  32  and judges whether the switch state is any of the selected support state and the non-selected state selected by the selection switch  32 . Further, the switch state obtaining/judging portion  41  obtains the ON/OFF state of the stimulus imparting switch  33  from the stimulus imparting switch  33  and judges whether the state of the stimulus imparting switch  33  is ON or OFF. 
     The drowsiness eliminating judging portion  42  judges whether or not it is necessary to eliminate the drowsiness (drowsiness elimination) of the driver M sitting on the vehicle seat  20  (drowsiness eliminating judgement). The drowsiness eliminating judging portion  42  executes the drowsiness elimination judgement when the judgement result that the drowsiness eliminating support is selected by the selection switch  32  is obtained from the switch state obtaining/judging portion  41 . 
     The drowsiness eliminating judging portion  42  obtains the detection result of the driver monitor  31  (whether the driver M is drowsy or not) from the driver monitor  31 . The drowsiness eliminating judging portion  42  judges that it is necessary to eliminate the drowsiness of the driver M when the drowsiness eliminating judging portion  42  obtains the detection result that the driver M is drowsy. It is noted that the driver monitor  31  detects that the driver M is drowsy when the facial expression of the driver M changes, such as an increase of the number of yawning, an increase (or decrease) of the number of blinking or a closing state of eyelid. 
     It is noted that the facial expression change of the judgement subject may be configured to be selectable by the driver M. Further, it may be possible to configure that the facial expression change before and after the stimulus imparting switch  33  is ON is memorized in advance and derives facial expression changes specific to the driver M. Then, such specific facial expression changes are used for judgement of expression change of the subject. 
     When the first stimulus pattern determining portion  43   a  obtains the judgement result that the stimulus imparting switch  33  is turned ON from the switch state obtaining/judging portion  41 , the first stimulus pattern determining portion  43   a  determines the first stimulus pattern. The first stimulus pattern is the base stimulus pattern. It is preferable to set the frequency from 90 to 110 Hz and to set the one time continuous imparting time from 20 to 40 seconds for the first stimulus patterns of the first stimulus imparting device  14  and the third stimulus imparting device  16  among the first stimulus patterns. It is also preferable to set the frequency to be 100 Hz and is preferable to set the continuous imparting time to be 30 seconds. 
     Further, it is preferable to set the frequency from 40 to 60 Hz and to set the one time continuous imparting time from 20 to 40 seconds for the first stimulus patterns of the second stimulus imparting device  15  and the fourth stimulus imparting device  17  among the first stimulus patterns when the stimulus imparted is the vibration stimulus. It is preferable to set the magnitude of pressing force from 1 to 2 kgf (kilogram-weight) and to set the one time continuous imparting time from 20 to 40 seconds for the patterns of the second stimulus imparting device  15  and the fourth stimulus imparting device  17  among the first stimulus patterns when the stimulus imparted is the stimulus of pressing force. 
     The optimum frequency is derived from the experimental work. The experimental result is shown in  FIG. 9 .  FIG. 9  indicates the experimental result that a vibration stimulus is imparted to the origin side (rib) tendon (including muscle tendon junction) of upper side fiber among the tendon portion of latissimus dorsi when a person in test is at the first drowsiness level where the person does not feel drowsy. The horizontal axis indicates the time between the imparting stimulus is started and a certain time period passed therefrom and the vertical axis indicates the level of drowsiness. 
     The time for continuously imparting stimulus is fixed to thirty seconds and the drowsiness level is measured by changing the frequency from 50 Hz to 120 Hz. The drowsiness level is defined by self-assessment of the subject person or may be defined by measurement. The white square indicates the change of drowsiness level when the stimulus is imparted for thirty seconds continuously with the frequency of 50 Hz, the diamond indicates the change of drowsiness level when the stimulus is imparted for thirty seconds continuously with the frequency of 80 Hz, the circle indicates the change of drowsiness level when the stimulus is imparted for thirty seconds continuously with the frequency of 100 Hz and the triangle indicates change of drowsiness level when the stimulus is imparted for thirty seconds continuously with the frequency of 120 Hz. As apparent from the experimental result, the optimum frequency is 100 Hz. From the peak frequency of 100 Hz, the drowsiness level goes to the drowsiness side when the frequency goes down or up from this peak frequency. 
     The optimum one time continuous imparting time is derived from the experimental work as well. The experimental result is shown in  FIG. 10 .  FIG. 10  indicates the experimental result that a vibration stimulus is imparted to the origin side (rib) tendon (including muscle tendon junction) of upper side fiber among the tendon portion of latissimus dorsi when a person in test is at a first drowsiness level where the person does not feel drowsy. The horizontal axis indicates the time between the imparting stimulus is started and a certain time period passed therefrom and the vertical axis indicates the level of drowsiness. 
     The frequency is fixed to 100 Hz and the drowsiness level is measured by changing the continuous imparting time from 15 to 60 seconds. The drowsiness level is defined by self-assessment of the subject person or may be defined by measurement. The white square indicates the change of drowsiness level when the stimulus is imparted for fifteen seconds continuously with the frequency of 100 Hz, the circle indicates the change of drowsiness level when the stimulus is imparted for thirty seconds continuously with the frequency of 100 Hz and the triangle indicates change of drowsiness level when the stimulus is imparted for sixty seconds continuously with the frequency of 100 Hz. As apparent from the experimental result, the optimum continuous imparting time is thirty seconds. The drowsiness level goes up to the drowsiness side from an early time in the case of fifteen seconds imparting time or sixty seconds imparting time. 
     As explained above, the stimulus imparted with the frequency of 100 Hz and with one time continuous imparting time of thirty seconds has the highest awakening effect. This effect can be achieved not only at the tendon of the latissimus dorsi but also at the tendon of gluteus medius muscle (particularly, the origin side tendon (including muscle tendon junction)). 
     The first stimulus pattern may be the stimulus pattern in which the vibration that vibrates all stimulus imparting device groups  12 R,  12 L,  13 R and  13 L at the same time (all vibrations) is repeatedly imparted or may be the stimulus pattern in which the vibration that vibrates only the right side first stimulus imparting device  14 R and the left side first stimulus imparting device  14 L at the same time (latissimus dorsi vibration) is repeatedly imparted, or further may be the stimulus pattern in which the vibration that vibrates only the right side third stimulus imparting device  16 R and the left side third stimulus imparting device  16 L at the same time (gluteus medius muscle vibration) is repeatedly imparted. It may also be the stimulus pattern in which all vibrations at the first time, the latissimus dorsi vibration at the second time and the gluteus medius muscle vibration at the third time are imparted and thereafter this order imparting stimulus is repeated. The order of the stimulus imparting is not limited to the above order. Further, the stimulus pattern may include the vibration that vibrates only the right side stimulus imparting device groups  12 R and  13 R (right side vibration) and the vibration that vibrates only the left side stimulus imparting device groups  12 L and  13 L (left side vibration). 
     The second stimulus pattern determining portion  43   b  determines the second stimulus pattern which eliminates the drowsiness of the driver M when the drowsiness eliminating judging portion  42  judges that it is necessary to eliminate the drowsiness of the driver M. The second stimulus pattern is basically the same with the first stimulus pattern. 
     The driving control portion  44  drives at least one of the first stimulus imparting device group  12  and the second stimulus imparting device group  13  based on each stimulus pattern determined by each stimulus pattern determining portion  43   a  and  43   b  to thereby impart stimulus to the driver M. 
     When it is judged that the drowsiness of the driver M is necessary to be eliminated, the driving control portion  44  drives the stimulus imparting device groups  12 R,  12 L,  13 R and  13 L based on the first stimulus pattern to impart the stimulus to the driver M to perform the drowsiness eliminating support which eliminates the drowsiness of the driver M. Further, when the driver M itself demands the stimulus (when the driver M turns the stimulus imparting switch  33  on), the driving control portion  44  drives the stimulus imparting device groups  12 R,  12 L,  13 R and  13 L based on the first stimulus pattern to impart the stimulus to the driver M to perform the drowsiness eliminating support which eliminates the drowsiness of the driver M. 
     The effect of the stimulus imparted to the driver M will be explained hereinafter. The drowsiness eliminating effect among the effects when the stimulus is imparted to particular human body portions is shown in  FIG. 11  and  FIG. 12 .  FIG. 11  indicates the experimental result that a vibration stimulus is imparted to the origin side (rib) tendon (including muscle tendon junction) of upper side fiber latissimus dorsi of a person in test when the person in test is at a third drowsiness level where the person feels drowsy. The imparted vibration stimulus is a stimulus with the frequency of 100 Hz with thirty second continuously imparted time. The white square indicates the timing of vibration stimulus imparting and this timing agrees with the timing that the person in test has reached to the third drowsiness level at which the person in test feels drowsy. The timing immediately after the vibration stimulus is imparted indicates the non-drowsy first drowsiness level. Thus, from this experiment, it is confirmed that imparting the vibration stimulus has a high effect in drowsiness elimination. 
       FIG. 12  indicates the experimental result that a vibration stimulus is imparted to the origin side tendon (including muscle tendon junction) of gluteus medius muscle of a person in test when the person in test is at a third drowsiness level where the person feels drowsy. The vibration stimulus imparted is a stimulus with the frequency of 100 Hz with thirty second continuously imparted time. The white square indicates the timing of vibration stimulus imparting and this timing agrees with the timing that the person in test has reached to the third drowsiness level at which the person in test feels drowsy. The timing immediately after the vibration stimulus is imparted indicates the non-drowsy first drowsiness level. Thus, from this experiment, it is confirmed that imparting the vibration stimulus has a high effect in drowsiness elimination. Further, the drowsiness eliminating effect (drowsiness generation suppression effect) of imparting stimulus to the tendon of gluteus medius muscle is longer maintained than the drowsiness eliminating effect of imparting stimulus to the tendon of latissimus dorsi. 
     Further, the effect of imparting stimulus to both particular human body portion (such as for example, tendon of latissimus dorsi and tendon of gluteus medius muscle) and a skin portion (inferior angle of scapula to the armpit portion and the femur outside portions) in the vicinity of skeletal muscle associated with the motion illusion induced at the supplementary motor area activated by the stimulus to the particular human body portion will be explained with reference to  FIGS. 13 through 15 . It is noted that  FIGS. 13 through 15  show the latissimus dorsi and gluteus medius muscle and the inferior angle of scapula to the armpit portion is omitted. 
       FIG. 13  indicates the experimental result that a vibration stimulus is imparted to only the tendon of gluteus medius muscle of a person in test when the person in test is at a third drowsiness level where the person feels drowsy. The vibration stimulus imparted is a stimulus with the frequency of 100 Hz with thirty second continuously imparted time. The white square indicates the timing of vibration stimulus imparting and this timing agrees with the timing that the person in test has reached to the third drowsiness level at which the person in test feels drowsy. When the stimulus is imparted, the drowsiness level goes down to the second level where the person feels slightly drowsy or the first level where the person feels non-drowsy. In other words, the drowsiness has been eliminated. However, such stimulus is imparted several times, even such stimulus is imparted the drowsiness level does not go down the drowsiness is not eliminated. The drowsiness level goes up to the fourth drowsiness level at which level, a person feels very drowsy. The time from the first imparting stimulus to the time when the drowsiness level reaches to the fourth drowsiness level is about fifteen minutes. Within the fifteen minutes, the first drowsiness level of non-drowsy is about one minute, the second drowsiness level of slightly drowsy is about twelve minutes and the third drowsiness level of drowsy is about two minutes. 
     On the contrary,  FIG. 14  indicates the experimental result that the vibration stimulus is imparted to both tendon portion of the gluteus medius muscle and the skin portion of the femur outside portions when the person in test is at a third drowsiness level where the person feels drowsy. The vibration stimulus imparted to the tendon portion of the gluteus medius muscle is a stimulus with the frequency of 100 Hz with thirty second continuously imparted time. The vibration stimulus imparted to the skin portion of the femur outside portion is a stimulus with the frequency of 50 Hz with thirty second continuously imparted time. The white square indicates the timing of vibration stimulus imparting and this timing agrees with the timing that the person in test has reached to the third drowsiness level at which the person in test feels drowsy. When the stimulus is imparted, the drowsiness level goes down to the second level where the person feels slightly drowsy or the first level where the person feels non-drowsy. In other words, the drowsiness has been eliminated. However, such stimulus is imparted several times, even such stimulus is imparted the drowsiness level does not go down the drowsiness is not eliminated. The drowsiness level goes up to the fourth drowsiness level at which level, a person feels very drowsy. The time from the first imparting stimulus to the time when the drowsiness level reaches to the fourth drowsiness level is about thirty minutes. Within the thirty minutes, the first drowsiness level of non-drowsy is about eighteen minutes, the second drowsiness level of slightly drowsy is about eleven minutes and the third drowsiness level of drowsy is about one minute. 
     Thus, the time of the third drowsiness level or below the third drowsiness level from the stimulus imparting starting, which is one parameter that indicates the drowsiness eliminating effect, is longer in the case of the stimulus imparting to both tendon portion of the gluteus medius muscle and the skin portion of the femur outside portion than in the case of the stimulus imparting only to the tendon of gluteus medius muscle. Further, the ratio of the time the first drowsiness level or the second drowsiness level occupies is larger than the ratio of the time the third drowsiness level or below the third drowsiness level occupies from the stimulus imparting starting, which is one parameter that indicates the drowsiness eliminating effect. 
     It is noted that as a reference data,  FIG. 15  indicates the experimental result that a vibration stimulus is imparted to only to the skin portion of the femur outside portion of a person in test when the person is in the third drowsiness level. The vibration stimulus imparted to the skin portion of the femur outside portion is the stimulus which frequency is 50 Hz and the time of imparting stimulus continuously is thirty seconds. The white square indicates the timing of vibration stimulus imparting and this timing agrees with the timing that the person in test reached to the third drowsiness level at which the person in test feels drowsy. When the vibration stimulus is imparted, the drowsiness level goes down to the second drowsiness level at which the person in test feels slightly drowsy but does not go down to the first drowsiness level which is a non-drowsy level. In other words, the drowsiness has been somewhat eliminated. However, when the vibration stimulus is imparted a number of times, even the vibration stimulus is imparted, the drowsiness cannot be eliminated. At this timing, the drowsiness level does not go down but goes up to the fourth drowsiness level. The time from the first imparting stimulus to the time when the drowsiness level reaches to the fourth drowsiness level is about six minutes. Within the six minutes, the first drowsiness level of non-drowsy is zero minute, the second drowsiness level of slightly drowsy is about two minutes and the third drowsiness level of drowsy is about four minutes. 
     It is noted that  FIGS. 13 through 15  show the gluteus medius muscle and femur outside portion and the latissimus dorsi and the inferior angle of scapula to the armpit portion are omitted. However, similar to the gluteus medius muscle and femur outside portion and the latissimus dorsi, similar tendency of the awakening effect for the latissimus dorsi and the inferior angle of scapula to the armpit portion is expected. 
     As shown in  FIGS. 4 and 5 , the drowsiness generation eliminating effect among the effects when the stimulus is imparted to particular human body portions is that the drowsiness level at latissimus dorsi and the gluteus medius muscle is maintained to the first drowsiness level of non-drowsy for relatively a long period of time. Accordingly, the drowsiness generation suppression effect is high when the stimulus is imparted to the latissimus dorsi and the gluteus medius muscle, i.e., a high awakening effect can be maintained. 
     The operation of above structured drowsiness eliminating device  10  will be explained hereinafter with reference to the flowchart shown in  FIG. 16 . 
     The control device  40  obtains and judges the switch state of the selection switch  32  and the stimulus imparting switch  33  at the step S 102 , as similar to the above explained switch state obtaining/judging portion  41 . In other words, the control device  40  judges whether the selection switch  32  and the stimulus imparting switch  33  are operated or not. 
     When the selection switch  32  and the stimulus imparting switch  33  are not operated, the control device  40  repeatedly executes the processing of the step S 102 . When the selection switch  32  and the stimulus imparting switch  33  are operated, then the control device  40  advances the program to the step S 104  and thereafter. 
     At the step S 104 , the control device  40  judges the operated switch as similar to the above explained switch state obtaining/judging portion  41 . When the stimulus imparting switch  33  is ON, the control device  40  advances the program to the step S 106  or when the selection that the drowsiness eliminating support is necessary is selected, the control device  40  advances the program to the step S 110 . 
     When the stimulus imparting switch  33  is ON (i.e., when the driver M itself demands the stimulus imparting), the control device  40  determines the first stimulus pattern at the step S 106 , as similar to the first stimulus pattern determining portion  43   a . Then, at the step S 108 , the control device  40  controls to drive each of the stimulus imparting device groups  12 R,  12 L,  13 R and  13 L based on the first stimulus pattern as similar to the above explained driving control portion  44  thereby to impart stimulus to the driver M to support drowsiness elimination which eliminates the drowsiness of the driver M. 
     The control device  40  judges whether or not the elimination of the drowsiness of the driver M seated on the vehicle seat (drowsiness elimination) is necessary at the steps S 104 , S 110  and S 112  (drowsiness eliminating judgement), as similar to the above explained drowsiness eliminating judging portion  42  (judging portion). In detail, the control device  40  judges that it is necessary to eliminate a drowsiness of the driver M, when expression change of the judgement subject is selected (determined) (“YES” at the step S 110 ) and the selected expression change appears (“YES” at the step S 112 ). 
     When it is judged that it is necessary to eliminate a drowsiness of the driver M, the control device  40  determines the second stimulus pattern at the step S 114 , as similar to the above explained second stimulus pattern determining portion  43   b . Then, at the step S 116 , the control device  40  controls to drive each stimulus imparting device group  12 R,  12 L,  13 R and  13 L based on the second stimulus pattern, as similar to the above explained driving control portion  44 , thereby to impart stimulus to the driver M. Thus, the drowsiness eliminating support for the driver M is performed. 
     As apparent from the first embodiment, the drowsiness eliminating device according to the first embodiment includes at least one of a first stimulus imparting device group  12  including a first stimulus imparting device  14  provided on a vehicle seat  20  (chair) such that the tendon of latissimus dorsi of a driver M (user) of the vehicle seat  20  faces when the driver M sits on the vehicle seat  20  and imparting stimulus to the tendon of latissimus dorsi of the driver M and a second stimulus imparting device  15  provided on the vehicle seat  20  facing a first skin portion when the driver M sits on the vehicle seat  20  and imparting the stimulus to the first skin portion of the driver M which is a skin part covering a skeletal muscle which is associated with a first motion illusion induced at a supplementary motor area activated by the stimulus to the tendon of latissimus dorsi and which is a cooperative muscle of the latissimus dorsi and a second stimulus imparting device group  13  including a third stimulus imparting device  16  provided on the vehicle seat  20  such that the tendon of gluteus medius muscle of the driver M of the vehicle seat  20  faces when the driver M sits on the vehicle seat and imparting the stimulus to the tendon of gluteus medius muscle of the driver M and a fourth stimulus imparting device  17  provided on the vehicle seat facing a second skin portion when the driver M sits on the vehicle seat  20  and imparting the stimulus to the second skin portion of the driver M which is a skin part covering a skeletal muscle which is associated with a second motion illusion induced at a supplementary motor area activated by the stimulus to the tendon of the gluteus medius muscle and which is a cooperative muscle of the gluteus medius muscle and a drive control device  40  which includes a driving control portion  44  which drive-controls said at least one of the first stimulus imparting device group and the second stimulus imparting device group to impart a stimulus to the driver M of the vehicle seat  20 . 
     According to the configuration, the driving control portion  44  imparts stimulus to the tendon of latissimus dorsi of the driver M by the first stimulus imparting device  14  and to the first skin portion of the driver M by the second stimulus imparting device  15 , and/or the driving control portion  44  imparts stimulus to the tendon of gluteus medius muscle of the driver M by the third stimulus imparting device  16  and to the second skin portion of the driver M by the fourth stimulus imparting device  17 . Accordingly, in addition to properly stimulating tendon of latissimus dorsi and/or gluteus medius muscle which are the body parts highly effective to awaken the driver M, it is possible to properly stimulate a first skin portion which is a skin part covering the skeletal muscle which is associated with a first motion illusion which is induced at the supplementary motor area activated by the stimulus to the tendon of latissimus dorsi and which is a cooperative muscle of the latissimus dorsi of the driver M of the vehicle seat  20  and/or to properly stimulate a second skin portion which is a skin part covering the skeletal muscle which is associated with a second motion illusion which is induced at the supplementary motor area activated by the stimulus to the tendon of gluteus medius muscle and which is a cooperative muscle of the gluteus medius muscle of the driver M. Thus, by simulating two portions which awakening effects are mutually correlated to thereby achieve a higher awakening effect. Accordingly, the drowsiness eliminating device  10  can properly stimulate the portions where the awakening effect is high. 
     Further, the strength of the stimulus imparted from the second stimulus imparting device  15  is set to be smaller than the strength from the first stimulus imparting device  14  and the strength of the stimulus imparted from the fourth stimulus imparting device  17  is set to be smaller than the strength from the third stimulus imparting device  16 . 
     According to the configuration, the drowsiness eliminating device  10  can effectively achieve the awakening effect by properly imparting the stimulus depending on the place or portion where the stimulus is imparted. 
     Thus, when the stimulus imparted from the second stimulus imparting device  15  and the fourth stimulus imparting device  17  is the vibration stimulus, the frequency of the vibration can be set to the frequency from 40 Hz to 60 Hz. 
     According to this configuration, the drowsiness eliminating device  10  can impart more appropriate stimulus to a portion which is highly effective in awakening effect. 
     When the stimulus imparted from the second stimulus imparting device  15  and the fourth stimulus imparting device  17  is the pressing force stimulus, the magnitude of the pressing force can be set to the value from 1 to 2 kgf (kilogram-force). 
     According to this configuration, the drowsiness eliminating device  10  can impart more appropriate stimulus to a portion which is highly effective in awakening. 
     Further, the drowsiness eliminating device includes the drowsiness eliminating judging portion  42  (judging portion) which judges whether or not it is necessary to eliminate the drowsiness of the driver M sitting on the vehicle seat  20  and the first stimulus pattern determining portion  43   a  which determines the first stimulus pattern for eliminating the drowsiness when the drowsiness eliminating judging portion  42  judges that it is necessary to eliminate the drowsiness of the driver M, wherein the driving control portion  44  imparts the stimulus to the driver M by drive-controlling at least one of the first stimulus imparting device group  12  and the second stimulus imparting device group  13  to impart a stimulus to the driver M based on the first stimulus pattern determined by the first stimulus pattern determining portion  43   a . According to this configuration, the drowsiness eliminating device  10  can impart more appropriate stimulus to a portion which is highly effective in awakening effect. 
     The “chair” corresponds to the vehicle seat  20  installed in the vehicle A and the “user” corresponds to the driver M. 
     According to this configuration, the drowsiness eliminating device  10  which can properly impart the stimulus to a portion which is highly effective to the awakening effect can be applicable to the vehicle A and as a result, the drowsiness of the driver M can be sufficiently eliminated. 
     Second Embodiment 
     Next, the second embodiment will be explained with reference to  FIG. 17 . The second embodiment is different from the first embodiment (applied to the vehicle) in applying the application to a furniture. In detail, the chair corresponds to a chair  120 , instead of the vehicle seat  20 . The control device  40  is housed in the main body  11  of the drowsiness eliminating device  10 . 
     The chair  120  is a chair on which the user M sits and is formed by a seat cushion  121  and a seat back  122  and a plurality of legs  123 . The chair  120  is used with a desk  50  as a set. The desk  50  is formed by a board portion  52  and a plurality of leg portions  51 . A user monitor  31 , a selection switch  32  and a stimulus imparting switch  33  are arranged in the vicinity of the desk  50 . Other configurations are the same with those of the first embodiment and the explanation thereof will be omitted with the same reference numerals. 
     The drowsiness eliminating device according to the second embodiment configured as explained above includes, similar to the first embodiment, at least one of a first stimulus imparting device group  12  including a first stimulus imparting device  14  provided on a chair  120  such that the tendon of latissimus dorsi of a user M of the chair  120  faces when the user M sits on the chair  120  and imparting a stimulus to the tendon of latissimus dorsi of the user M and a second stimulus imparting device  15  provided on the chair  120  facing a first skin portion when the user M sits on the chair  120  and imparting the stimulus to the first skin portion of the user M which is a skin part covering a skeletal muscle which is associated with a first motion illusion induced at a supplementary motor area activated by the stimulus to the tendon of latissimus dorsi and which is a cooperative muscle of the latissimus dorsi and a second stimulus imparting device group  13  including a third stimulus imparting device  16  provided on the chair  120  such that the tendon of gluteus medius muscle of the user M of the chair  120  faces when the user M sits on the chair  120  and imparting a stimulus to the tendon of gluteus medius muscle of the user M and a fourth stimulus imparting device  17  provided on the chair  120  facing a second skin portion when the user M sits on the chair  120  and imparting the stimulus to the second skin portion of the user M which is a skin part covering a skeletal muscle which is associated with a second motion illusion induced at a supplementary motor area activated by the stimulus to the tendon of gluteus medius muscle and which is a cooperative muscle of the gluteus medius muscle and a drive control device  40  which includes a driving control portion  44  which drive-controls at least one of the first stimulus imparting device group and the second stimulus imparting device group to impart a stimulus to the user M of the chair  120 . 
     According to the configuration, the driving control portion  44  imparts stimulus to the tendon of latissimus dorsi of the user M by the first stimulus imparting device  14  and to the first skin portion of the user M by the second stimulus imparting device  15 , and/or the driving control portion  44  imparts stimulus to the tendon of gluteus medius muscle of the user M by the third stimulus imparting device  16  and to the second skin portion of the user M by the fourth stimulus imparting device  17 . Accordingly, in addition to properly stimulating tendon of latissimus dorsi and/or gluteus medius muscle which are the body parts highly effective to awaken the user M, it is possible to properly stimulate a first skin portion which is a skin part covering the skeletal muscle which is associated with a first motion illusion which is induced at the supplementary motor area activated by the stimulus to the tendon of latissimus dorsi and which is a cooperative muscle of the latissimus dorsi of the user M of the chair  120  and/or to properly stimulate a second skin portion which is a skin part covering the skeletal muscle which is associated with a second motion illusion which is induced at the supplementary motor area activated by the stimulus to the tendon of gluteus medius muscle and which is a cooperative muscle of the gluteus medius muscle of the user M. Thus, by simulating two portions which awakening effects are mutually correlated to thereby achieve a higher awakening effect. Accordingly, the drowsiness eliminating device  10  can properly stimulate the portions where the awakening effect is high. 
     According to the embodiments explained above, the first stimulus imparting device group  12  and the second stimulus imparting device group  13  are both arranged. However, it may be configured to have only one of the first stimulus imparting device group  12  and the second stimulus imparting device group  13 . 
     Further, the driving control portion  44  is configured to drive both of the first stimulus imparting device group  12  and the second stimulus imparting device group  13 . However, it may be configured to drive either one of the first stimulus imparting device group  12  and the second stimulus imparting device group  13 . 
     Further, instead of using stimulus imparting switch  33 , a voice recognizing device is provided to request a stimulus by sound. 
     REFERENCE SIGNS LIST 
       10 ; drowsiness eliminating device,  11 ; main body,  12 ; first stimulus imparting device group,  13 ; second stimulus imparting device group,  14 ; first stimulus imparting device,  14 R; right side first stimulus imparting device,  14 L; left side first stimulus imparting device,  15 ; second stimulus imparting device,  15 R; right side second stimulus imparting device,  15 L; left side second stimulus imparting device,  16 ; third stimulus imparting device,  16 R; right side third stimulus imparting device,  16 L; left side third stimulus imparting device,  17 ; fourth stimulus imparting device,  17 R; right side fourth stimulus imparting device,  17 L; left side fourth stimulus imparting device,  20 ; vehicle seat (chair),  31 ; driver monitor, user monitor,  32 ; selection switch,  33 ; stimulus imparting switch,  40 ; control device,  41 ; switch state obtaining/judging portion,  42 ; drowsiness eliminating judging portion,  43   a ;  43   b ; each stimulus pattern determining portion,  44 ; driving control portion,  120 ; chair, A; vehicle, M; driver/user