JP5476153B2 - Portable information terminal - Google Patents

Description

The present invention relates to a portable information terminal having a built-in vibration sensor that detect vibrations.

  Many of vibration sensors and acceleration sensors that detect vibration have a built-in weight and detect the relative movement of the sensor body and the weight caused by the vibration. As a detection principle of this sensor, a piezoresistive type, a capacitance type, or a piezoelectric type is known (for example, see Patent Document 1). In any case, the sensitivity of the sensor depends on the mass of the weight. Basically, however, the sensitivity tends to decrease when the size of the entire sensor is reduced.

On the other hand, recent portable information terminals have various sensors built therein, and vibration sensors and acceleration sensors are one of them. For example, it has been proposed to use a triaxial acceleration sensor for the purpose of discriminating the usage status of a portable information terminal and performing power wakeup control (see, for example, Patent Document 2).
There is also a portable information terminal that can measure the number of steps by externally attaching an acceleration sensor (see, for example, Patent Document 3). Attempts have also begun to acquire body sounds such as heart sounds using a portable information terminal and monitor health (for example, see Patent Document 4).

  On the other hand, in the technical field of condenser microphones used for communication equipment terminals and audio devices, in recent years, small silicon capacitors using MEMS (Micro Electro Mechanical System) microphone chips manufactured by applying micromachining technology to semiconductor processing. A microphone is known (see, for example, Patent Document 5). This MEMS microphone chip is usually used in a state where a package is mounted on a printed board.

  As an attempt to use such a condenser microphone as a vibration sensor, a method using a sensor unit in which a condenser microphone is provided in a hollow frame formed of a flexible body has been proposed (see Patent Document 6). In this method, vibration data attributed to the human body is extracted by laying the sensor unit under the human body in the lying posture, and the heart rate, the respiratory rate, the time for turning over, and the number of wrinkles are estimated.

Japanese Patent Publication No. 5-46902 JP 2009-63563 A JP 2009-106374 A JP 2007-159682 A JP 2004-537182 A Japanese Patent Laid-Open No. 11-28195

If a vibration sensor or acceleration sensor for detecting vibration is built in the portable information terminal, it is possible to measure the vibration applied to the portable information terminal. However, functions built in portable information terminals are increasing, and it is required to reduce or reduce the number of components to be mounted.
The present invention has been made to solve the above problems, and its object is to provide a portable information terminal having a built-positivity vibration sensors smaller and closed like with the housing is folded It is to realize a portable information terminal capable of detecting vibrations using a microphone built in a housing in a state.

A portable information terminal according to the present invention has a frame shape having a hole, a flexible member having a property of deforming according to an applied external force and returning to its original shape when the external force is lost, and a housing for accommodating a microphone Including a portion and another portion, and the positional relationship between the housing portion and the other portion is in a first state (for example, a state where the portable information terminal is closed) or a second state (for example, a portable information terminal) When the positional relationship is in the first state, the space of the accommodating portion and the other portion are connected via the hole of the flexible member. Thus, a sealed space is formed, and a change in air pressure in the sealed space is detected by the microphone. According to this configuration, the portable information terminal can function as a vibration sensor when the portable information terminal is in the closed state. In that case, since either one of the microphone housing part or the other part acts as a weight, vibration can be detected well. And the structure for a telephone call can be used also as a structure for detecting a vibration, and the influence on the size of a portable information terminal can be suppressed.

The microphone is preferably composed of a MEMS element. According to this configuration, the configuration for detecting vibration can be further reduced, and the influence on the size of the portable information terminal can be suppressed.
The microphone is preferably housed in a package having a hole for the sealed space. According to this configuration, it is possible to efficiently detect a change in air pressure in the sealed space.
The portable information terminal may be attached to a living body walking and detect the number of steps of the living body based on the output of the microphone. Thereby, the vibration due to walking can be detected by the microphone, and the number of steps can be obtained.

The portable information terminal may be attached to a living body and detect at least one of a heart sound and a pulse of the living body based on an output of the microphone. Thereby, a heart sound and a pulse can be detected with a microphone, and a heart rate and a pulse rate can be obtained.
In the portable information terminal, based on the output of the microphone, the positional relationship between the housing part and the other part is in a first state (for example, a state in which the portable information terminal is closed) or a second state (for example, It may be detected that the portable information terminal is open). Thereby, the open / closed state of the mobile terminal can be known.

According to the present invention, by using the microphone provided in the sealed space, an effect that a portable information terminal incorporating a vibration sensor with a smaller size and higher sensitivity can be obtained. Further, by configuring the vibration sensor in a state where the housing is closed, an effect that a portable information terminal capable of detecting vibration can be realized is obtained.

It is a perspective view which shows the structure of one Embodiment of the vibration sensor of this invention. It is a schematic diagram which shows the cross-sectional structure of one Embodiment of the vibration sensor of this invention. It is a perspective view which shows the structure of the other form of the vibration sensor of this invention. It is a cross-sectional schematic diagram of the other form of the vibration sensor of this invention. It is a perspective view which shows the state which opened the housing | casing of an example of the portable information terminal of this invention. It is a perspective view which shows the state which closed the housing | casing of an example of the portable information terminal of this invention. It is a cross-sectional schematic diagram of the microphone vicinity in the state which closed the housing | casing of an example of the portable information terminal of this invention. It is an example of the waveform diagram which showed the output of the microphone when the portable information terminal by the Example of this invention was put in the pocket of clothes and walked. It is an example of the waveform diagram which showed the output of the microphone when the portable information terminal by the Example of this invention was put in the pocket of the shirt left chest part, and was made quiet. It is a block diagram which shows the structural example of the measurement circuit for counting the frequency | count of a walk vibration, or a heart rate. It is an example of the frequency spectrum of the output of the microphone detected in the state which opened and closed the case of an example of the portable information terminal of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings referred to in the following description, the same parts as those in the other drawings are denoted by the same reference numerals.
(Configuration example of vibration sensor)
FIG. 1 is a perspective view showing a configuration of an embodiment of the vibration sensor of the present invention, and FIG. 2 is a schematic diagram showing a cross-sectional configuration of the AA portion of FIG. Referring to both figures, the vibration sensor 1 of this example includes a structure 2 and a structure 3 that function as a casing, and a flexible member 6 positioned between the structure 2 and the structure 3. doing. Further, the vibration sensor 1 has a sealed space that is surrounded and sealed by the structure 2, the structure 3, and the flexible member 6. The flexible member 6 has a property of deforming according to an applied external force and returning to the original shape when the external force is lost. That is, the vibration sensor 1 is composed of two parts, a flexible part (flexible member 6) and a non-flexible part (structure 2 and structure 3). The soft and inflexible part is hardened to maintain its shape.

And in the structure 2, the microphone 5 which has the sound hole 7 connected to the opening part 70 to the sealed space is accommodated. The microphone 5 includes a microphone element 5a. The signal detected by the microphone element 5a can be derived by, for example, a lead wire (not shown).
In this example, a frame shape having a hole is adopted as the shape of the flexible member 6. Further, in this example, the structure 2 and the structure 3 have a substantially cylindrical shape, but are not limited to this shape, and may be a prism, a sphere, or any shape depending on the application. The shape may be adopted.

(Another configuration example of vibration sensor)
FIG. 3 is a perspective view showing a configuration of an embodiment of the vibration sensor of the present invention, and FIG. 4 is a schematic diagram showing a cross-sectional configuration of a BB portion of FIG. Referring to both figures, the vibration sensor 1a of the present example has a structure 2a that functions as a housing and a flexible member 6a provided on the upper part thereof. The vibration sensor 1a has a sealed space whose periphery is sealed by the structure 2a and the flexible member 6a. The structure 2 has a sound hole 7 serving as an opening portion to the sealed space. A microphone 5 is provided. The microphone 5 includes a microphone element 5a. The signal detected by the microphone element 5a can be derived by a lead wire (not shown).

In this example, the flexible member 6a has a sheet shape, and separates the sealed space from the outside of the housing. With this sheet-shaped flexible member 6a, a change in air pressure in the sealed space can be detected efficiently.
In this example, the structure 2 has a shape in which two substantially cylindrical shapes having different diameters are overlapped and connected. However, the structure 2 is not limited to this shape, and is a prism or a sphere. Or an arbitrary shape may be adopted depending on the application. Another structure may be connected on the flexible member 6a.

(Flexible material, non-flexible material)
The flexible material that forms the flexible member 6 and the flexible member 6a described above is a material that deforms when an external force is applied and returns to its original shape when the external force disappears. For example, rubber such as natural rubber, urethane rubber, and silicone rubber, gel, and elastomer can be given as examples of the flexible material.
The non-flexible material means a material that is less flexible (higher rigidity) than the above-described flexible material and does not easily deform even when an external force is applied. For example, metals and hard plastics can be given as examples of inflexible materials.

(Structure)
The above-described structures 2, 2a and 3 that function as a case mean a processed product or a combination thereof having a material and a shape suitable for the intended function, such as a case made of a metal plate or a plastic plate. Including those with hollow inside. These structures 2, 2a, and 3 may be configured using a flexible material, may be configured as a non-flexible material, or may be combined. However, from the viewpoint of maintaining the shape, an inflexible material is preferable.

1 and 2 exemplify a case in which one structure is composed of two structures 2 and 3 and one flexible member is combined with the structure. In this case, It is not limited to. That is, it may be three or more structures, two or more flexible members, or a combination of three or more structures and two or more flexible members. good. Needless to say, a sealed space can be configured in any case.
Here, the sealed space means that there is no air passage such as a gap or a hole between the external space. When there is a minute air passage between the sealed space and the external space, the sound pressure is leaked from there and the sensitivity is lowered, especially at low frequencies. Therefore, it is only necessary to have a hermeticity that does not lower the sensitivity in the frequency region actually used.

(microphone)
The microphone 5 is a device that receives a sound wave and generates a current having the same waveform. Examples of the microphone include a condenser microphone (electrostatic type), a moving coil microphone (electrodynamic type), a ribbon microphone (speed type), and a crystal microphone (piezoelectric type). In this example, a condenser microphone is preferable from the viewpoint that sealing and miniaturization are possible, and a silicon condenser microphone including an electret condenser microphone and a MEMS element is more preferable.

(Operating principle)
According to the above configuration, since at least a part of the wall surface constituting the sealed space is the flexible member, the vibration transmitted from the outside to the structure is subjected to the pressure change of the air in the sealed space (that is, the change of the air pressure). ). Therefore, by arranging the microphone 5 having the sound hole 7 in the sealed space, it is possible to measure the pressure change of the air in the sealed space, and to measure the vibration applied from the outside with the microphone 5. Become. The sensitivity to vibration depends on the mass of the structure in contact with the flexible member. However, since the mass of the structure is generally sufficiently large, the microphone 5 can measure vibration with high sensitivity.

  The pressure change of the air in the sealed space depends on the displacement amount of the flexible member of the inner wall of the sealed space due to vibration and the volume of the sealed space, and the smaller the ratio of the total volume to the volume change amount due to the vibration of the sealed space is, the smaller the ratio is. The sensitivity to vibration can be increased by increasing the pressure change. Therefore, by using the microphone 5 using the MEMS element, it is possible to perform vibration measurement with higher sensitivity by downsizing the microphone package. Further, the larger the area of the flexible member in the inner wall of the sealed space, the larger the pressure change and the higher the sensitivity to vibration. In addition, in vibration below the resonance frequency determined by the elastic constant of the flexible member and the mass of the structure, the smaller the volume modulus of elasticity of the flexible material constituting the flexible member, the greater the displacement, so the sensitivity is Get higher.

(Personal digital assistant)
Next, with reference to FIGS. 5 to 7, a configuration example of a portable information terminal configured using the above vibration sensor will be described. 5 is a perspective view showing a state where the casing of the portable information terminal is opened, FIG. 6 is a perspective view showing a state where the casing of the portable information terminal is closed, and FIG. 7 is a CC section (near the microphone) in FIG. It is a mimetic diagram showing the section composition of.
In FIG. 5, the portable information terminal 1 b of this example includes a housing 20 that houses a microphone and has the function as the structure 2 described above, and a housing 30 that has the function as the structure 3 described above. Yes. Since the housing 20 and the housing 30 are connected via a hinge, an opening / closing operation as indicated by an arrow Y about the axis J is possible. The figure shows a state where the housing 20 and the housing 30 are opened (that is, a state where the portable information terminal 1b is opened). In the figure, an input keyboard K is disposed in the housing 20, and a display D for display is disposed in the housing 30.

  In addition, the housing 20 is provided with an opening 70 for taking a voice or the like emitted by the terminal user into the housing. A frame-shaped flexible member 6 is provided around the opening 70. The flexible member 6 has a frame shape having a hole at the center. In other words, the flexible member 6 is provided so that the opening 70 is positioned in a frame-shaped hole (for example, a central portion of the frame shape). In this example, it is assumed that the flexible member 6 is bonded to the housing 20. The flexible member 6 is made of, for example, urethane gel having an Asker C hardness of 0, and has a thickness of, for example, 1 mm and a hole portion of, for example, a radius of 2 mm.

  On the other hand, FIG. 6 shows a state in which the housing 20 and the housing 30 are closed (that is, the portable information terminal 1b is folded). In the state shown in the figure, the housing 30 is in contact with the flexible member 6 of the housing 20. In this state, the housing 20 and the housing 30 are connected to face each other through the flexible member 6. In a state where these are connected, a sealed space is formed.

Here, referring to FIG. 7, which is a cross-sectional view of the vicinity of the microphone, the printed circuit board 4 is provided inside the housing 20. A package of the MEMS microphone 5 is mounted on the printed board 4. Further, the position of the sound hole 7 of the MEMS microphone 5 coincides with the position of the hole and the opening 70 of the flexible member 6. For this reason, a sealed space is formed by the housing 30, the flexible member 6, and the MEMS microphone 5 of the housing 20. At this time, the inner wall of the housing 20 and the upper part of the MEMS microphone 5 are in close contact with each other, and there is no gap other than the sound hole 7. According to this configuration, the portable information terminal can function as a vibration sensor when the portable information terminal is in the closed state. Further, since the MEMS microphone 5 is used, the configuration for detecting vibration can be made relatively small, and the influence on the size of the portable information terminal can be suppressed.
Of course, a sealed space can be formed even when the flexible member 6 is bonded to the housing 30 instead of the housing 20.

  As described above, the portable information terminal 1b functions as a vibration sensor using the MEMS microphone 5 in a state in which the portable information terminal 1b is folded to form a sealed space (generally in a state where communication is impossible). It will be. On the other hand, as shown in FIG. 5, in a state where the portable information terminal 1b is opened and becomes an open space (generally, a state where communication is possible), the MEMS microphone 5 functions as a mobile phone using a call microphone. Become. Thus, since one MEMS microphone 5 can be used for both vibration detection and telephone conversation, there is no need to separately prepare a vibration detection sensor and a telephone conversation microphone. For this reason, the structure for a telephone call can be used also as a structure for detecting a vibration, and the influence on the size of a portable information terminal can be suppressed.

The inventor confirmed that the produced prototype was a sealed space without a gap between the housing 30 and the flexible member 6 in a state where the portable information terminal 1b was folded. . As the MEMS microphone 5, SP0208 manufactured by Knowles was used. The sound hole 7 of the MEMS microphone 5 is connected to an opening 70 also provided in the housing 20.
According to this configuration, in the portable information terminal having the two cases 20 and 30 that can be opened and closed and the microphone 5, the positional relationship between the case 20 and the case 30 is in a closed state or an open state. In the open state, the microphone 5 is used for a call, and in the closed state, the microphone 5 and the two casings 20 and 30 constitute a vibration sensor to detect vibration applied to the portable information terminal. be able to.

  By the way, as such a portable information terminal, for example, a folding type, a sliding type and a rotary type cellular phone are known. In the foldable portable information terminal described with reference to FIGS. 5 and 6, the terminal main body is folded so that the casing 20 and the casing 30 overlap each other when the normal voice call or the like is not used. In this example, the package of the microphone 5 is accommodated in the housing 20 so that the space including the sound hole 7 of the microphone 5 becomes a sealed space in the folded state (that is, the closed state).

By adopting such a configuration, since the flexible material 6 is sandwiched between the two casings 20 and 30, one casing 30 functions as a weight of the vibration sensor, and a separate vibration sensor is not incorporated. However, vibration can be detected with high sensitivity using the microphone 5.
The sensitivity as a vibration sensor in this configuration depends on the ratio between the area of the hole provided in the flexible member 6 and the volume of the sealed space. That is, the greater the value of (area of hole) / (volume of sealed space), which is the ratio of the area of the hole to the volume of the sealed space, the greater the sensitivity. The vibration transmitted to the housing 20 serves as the weight of the vibration sensor, and the vibration transmitted to the housing 30 serves as the weight of the vibration sensor. Since the housing 20 and the housing 30 have a sufficiently large mass compared to the weight of a general small vibration sensor, the vibration sensor configured in this way exhibits excellent sensitivity.

(Configuration of vibration sensor using portable information terminal)
As an example of another application of such a portable information terminal, an application for detecting a heart sound or a pulse can be considered. That is, a heart sound or a pulse can be detected when the portable information terminal contacts the living body. In order to obtain the actual heart rate and pulse rate from the detected signal, it is preferable to remove noise using an algorithm that takes into account the periodicity of the interval. As will be described later, the noise can be eliminated by comparing with the threshold level.

 As another example of the use of the portable information terminal, a pedometer can be considered. That is, by carrying the portable information terminal during walking, vibration due to walking can be detected and the number of steps can be measured. In order to obtain the actual number of steps from the detected signal, it is preferable to remove noise using an algorithm that takes into account the periodicity of the interval. As an example of an algorithm used for removing noise, a known method such as the adaptive smoothing method described in the above-mentioned prior document 6 or a method for calculating the degree of correlation with an ideal signal waveform can be used. As will be described later, the noise can be eliminated by comparing with the threshold level.

(Detection of walking vibration)
The inventor simulated the portable information terminal of the embodiment in a simulated manner, and recorded the output of the MEMS microphone when walking in a pocket of the subject's clothes as shown in FIG. In the figure, the horizontal axis represents time, and the vertical axis represents voltage. Referring to the figure, the signal level is remarkably increased at the timings indicated by arrows Y1 to Y9. This part is vibration due to the walking of the subject. Therefore, the number of steps can be measured by counting the number of occurrences of this vibration.

(Heart sound detection)
Further, FIG. 9 shows the output of the MEMS microphone when the portable information terminal of the embodiment reproduced in a simulated manner is placed in the left chest pocket of the subject's shirt and rested. In the figure, the horizontal axis represents time, and the vertical axis represents voltage. Referring to the figure, the signal level increases at a constant period. This part is the subject's heart sound. Thus, if the portable information terminal of the present embodiment is used, heart sounds can be detected clearly. Therefore, the heart rate can be measured by counting the number of appearances of this heart sound. Not only the heart sound but also the pulse rate can be measured by detecting the pulse and counting the number of appearances. Moreover, it is not limited to a human body, and if it is attached to an animal body, its heart sound and pulse can be detected.

(Detection count measurement circuit)
FIG. 10 is a block diagram showing a configuration example of a measurement circuit for counting the number of walking vibrations or the heart rate.
In the figure, the measurement circuit of this example includes a three-state buffer 8 that receives the output of the MEMS microphone 5, a comparator 9 that receives the output of the three-state buffer 8, and an output 300 that is a comparison result of the comparator 9. And a counter 10 that performs a count-up operation.
In such a configuration, for example, a close detection signal 100 of a foldable portable information terminal having an open / close structure is applied to the control terminal of the three-state buffer 8. The open / closed state of the portable information terminal can be detected, for example, by combining a hall element and a magnet, and the closed detection signal 100 may be generated when the portable information terminal is in the closed state. There are portable information terminals that adopt a sliding type or a rotary type as an opening / closing structure other than the folding type, and it is only necessary to detect the opening / closing state and generate the closing detection signal 100 for these portable information terminals.

When the portable information terminal is open (callable state), the close detection signal 100 is not input, the 3-state buffer 8 is in a high impedance state, and the output of the MEMS microphone 5 is not input to the comparator 9. On the other hand, when the portable information terminal is folded and closed (call-disabled state), the output of the MEMS microphone 5 is input to the comparator 9. That is, the output of the MEMS microphone 5 is input to the comparator 9 only when the portable information terminal is closed. If the output of the MEMS microphone 5 needs to be always input to the comparator 9, it is not necessary to provide the three-state buffer 8.
The comparator 9 compares the output level of the three-state buffer 8 with the threshold level 200 and counts up the counter 10 only when the threshold level 200 is exceeded. Here, by appropriately setting the threshold level 200, it is possible to count the number of walking vibrations or the heart rate while eliminating noise.

(Detecting the open / close state of the chassis)
FIG. 11 shows the frequency spectrum of the output of the microphone with the portable information terminal of the embodiment reproduced in a simulated manner in the hand and with the housing closed and opened. In the figure, the horizontal axis represents frequency and the vertical axis represents output level. Referring to the figure, in a state where the casing is closed (denoted as “closed” in the figure), vibrations caused by the surrounding environment and the human body are measured. On the other hand, when the housing is open (indicated as “open” in the figure), this vibration is not measured and only background noise of the surrounding environment is measured, so the difference in level in the low frequency range is 20 dB. The above is clearly different. Therefore, by periodically monitoring the output level of the microphone in the low frequency range, the open / close state of the housing can be determined. As an algorithm for discrimination, comparison with a threshold level or detection of a change amount by periodic monitoring can be used.
The open / closed state of a portable information terminal can be detected for a case in which a sealed space is formed with a lid or the like closed and a sealed space is not formed with the lid or the like opened. .

(Summary)
The present inventor uses, as a vibration sensor, a microphone that is used for voice input in a state in which a housing is opened in a portable information terminal such as a mobile phone that has two housings that can be opened and closed and that has a microphone for speech input. Inspired to do. As a result of the study, it was found that a microphone can be used as a vibration sensor by forming a sealed space with a flexible member disposed between two cases with the two cases closed, and the present invention was completed. I let you.

According to the present invention, a portable information terminal incorporating a smaller vibration sensor can be realized by using a microphone provided in a sealed space. In addition, by configuring the vibration sensor in a state where communication is not possible, such as a state where the housing is closed, a portable information terminal capable of detecting vibration and detecting the number of steps, heart rate, and the like can be realized.
In addition, the present invention is not limited to a portable information terminal, and a highly sensitive vibration sensor can be realized by arranging a microphone in a sealed space constituted by two housings and a flexible member.

DESCRIPTION OF SYMBOLS 1, 1a Vibration sensor 1b Portable information terminal 2, 2a, 3 Structure 4 Printed circuit board 5 Microphone 5a Microphone element 6, 6a Flexible member 7 Sound hole 8 State buffer 9 Comparator 10 Counter 20, 30 Case 70 Opening 100 Close detection signal 200 Threshold level 300 Output D Display J Axis K Keyboard

Claims (6)

A flexible member that has a hole shape and has a property of deforming according to an applied external force and returning to the original shape when the external force is lost, a housing portion that houses a microphone, and another portion. Including
When the positional relationship between the accommodating portion and the other portion is in the first state or the second state, and the positional relationship is in the first state, the hole is formed through the hole of the flexible member. A portable information terminal characterized in that a sealed space is formed by connecting the space of the housing part and the other part, and a change in air pressure in the sealed space is detected by the microphone. The microphone, a portable information terminal according to claim 1, characterized in that it is constituted by the MEMS device. The microphone is a portable information terminal according to claim 1 or claim 2, characterized in that it is accommodated in a package having a hole portion that is connected to the enclosed space. The portable information terminal according to any one of claims 1 to 3 , wherein the portable information terminal is mounted on a walking living body and detects the number of steps of the living body based on an output of the microphone. The portable information terminal according to any one of claims 1 to 3 , wherein the portable information terminal is mounted on a living body and detects at least one of a heart sound and a pulse of the living body based on an output of the microphone. . The detection unit according to any one of claims 1 to 3 , wherein a positional relationship between the housing part and another part is detected based on an output of the microphone in a first state or a second state. The portable information terminal according to any one of claims.

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