JP2010148169A - Portable electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide portable electronic equipment wherein a thin power generating means is provided and a secondary battery can be very efficiently charged. <P>SOLUTION: The portable electronic equipment having a rechargeable secondary battery includes a piezoelectric power generating means capable of charging the secondary battery and furthermore with a capacitor. When a push button 6 is pressed during operation of a cellular phone 10, electromotive force is produced in an electrode of a piezoelectric sheet by a piezoelectric effect arising from the transmission of the resulting pressure to the piezoelectric sheet. Or, when the folding mechanism of the cellular phone is opened or closed, electromotive force is produced in an electrode of a piezoelectric element 8 by a piezoelectric effect arising from the collision of a protrusion 4 provided on the upper cover of a second enclosure 2 with the piezoelectric element 8 provided on the surface of a first enclosure. These electromotive forces are stored in the capacitor and the secondary battery is charged with the stored power. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a portable electronic device including a rechargeable secondary battery, and more particularly, to a portable electronic device including a power generation unit for charging the secondary battery.

  Portable electronic devices, especially portable communication devices such as mobile phones, PHS, and pagers (pagers), portable information terminals such as electronic notebooks, pocket computers, portable cassette tape recorders, portable CD players, portable MD recorders, PDAs In portable electronic devices such as electronic notebooks, video cameras, and digital cameras, secondary batteries are used. In general households, the secondary current is obtained by rectifying a household power supply. Charging is performed by supplying the battery, and in an automobile, charging is performed directly by a device with an overcharge prevention circuit or after being converted into a predetermined voltage by a DC-DC converter.

  However, in the conventional portable electronic device, since the secondary battery is exclusively used for the power source, for example, in the case of a mobile phone, the voltage of the secondary battery decreases during the call and the call is made. If the portable computer is used in the car, there is a problem that the work is interrupted due to the voltage drop of the secondary battery.

  Thus, in the case of a conventional portable electronic device, the operation time by the secondary battery is, for example, 1 to 2 hours for a call time or 50 to 300 hours for a continuous waiting time for a mobile phone. Therefore, it is necessary to charge almost every few days. In portable computer devices, the backlight of the liquid crystal display and the power consumption of the CPU (Central Processing Unit) are large, and the charging frequency is increased. In addition, it is necessary to consider the amount of charge of the secondary battery, and this work is very complicated, and in the event of an emergency such as a disaster, the charging work may not be in time, and there is a risk that an unusable situation may occur. .

To solve this problem, the portable electronic device has a built-in power generation means, and uses the movement of the human body to operate the power generation means to generate power to charge the built-in secondary battery in the portable electronic device. The thing is proposed (for example, patent document 1 and patent document 2).

JP 2003-298731 A JP 2006-149166 A

  However, in the above-described prior art, for example, the power generation mechanism described in Patent Document 1 is a mechanism that generates power by the relative movement of the magnet and the induction coil, so that the space of the power generation mechanism becomes relatively large and the portable electronic device becomes When built in, there is a problem that the space for incorporating other components becomes narrow. The power generation mechanism described in Patent Document 2 uses a sheet-like pressure sensor (piezoelectric element), and rectifies the output from the pressure sensor and connects it to a built-in rechargeable battery (secondary battery). However, usually, the output from the piezoelectric element is instantaneous and sporadic, and there is a problem that charging efficiency is poor even if the secondary battery is charged as it is.

The present invention has been made in view of the above-described points, and an object of the present invention is to provide a portable electronic device that includes a thin power generation unit and can recharge a secondary battery extremely efficiently. .

  As a result of intensive studies on a portable electronic device having a rechargeable secondary battery, the present inventors can achieve the above object by configuring the portable electronic device as follows. As a result, the present invention has been made.

In other words, the portable electronic device includes a rechargeable secondary battery, and further includes a piezoelectric power generation unit that can charge the secondary battery and a capacitor.

  Since the secondary battery is charged after the electric power generated by the piezoelectric power generation means is once stored in the capacitor, the secondary battery can be charged efficiently.

  The portable electronic device of the present invention will be described below with reference to the drawings. FIG. 1 shows a mobile phone as an example of the portable electronic device of the present invention. The cellular phone 10 of this example is a foldable type, and has a second casing 2 having a plurality of push buttons 6 on the upper surface thereof, and a hinge portion 3 with respect to the second casing 2. And a first housing 1 having a display unit 7 that can be folded through.

  A protrusion 4 that receives the first housing 1 when the cellular phone is folded is provided at the end of the upper surface of the second housing 2 opposite to the hinge portion 3. A first piezoelectric element 8 is disposed on the surface of the first housing 1 that comes into contact with the protrusion 4 when the cellular phone is folded. As the piezoelectric element, a conventionally known piezoelectric element such as lead zirconate titanate or barium titanate is used.

  FIG. 2 is an exploded perspective view showing the component configuration of the second housing 2. The second housing 2 is configured by sandwiching a push button sheet 22 and a piezoelectric sheet 23 as a second piezoelectric element between an upper cover 21 and a lower housing 24. The upper cover 21 has openings corresponding to the plurality of push buttons 6 disposed on the push button sheet 22.

  A secondary battery 25, a charge control circuit 26, a capacitor 27, a voltage control circuit 28, and a rectifier circuit 29 are disposed inside the second housing 2.

  The piezoelectric sheet 23 is configured by sandwiching a sheet material such as polyvinylidene fluoride having a piezoelectric effect between electrodes such as aluminum foil.

  The charging operation of the mobile phone 10 of this example will be described. First, the first charging operation mode will be described. When the operation of the cellular phone such as mail transmission is performed by pressing the push button 6 disposed on the push button sheet 22, the pressure due to the pressing is transmitted to the piezoelectric sheet (second piezoelectric element) 23, and the piezoelectric effect causes the piezoelectric sheet. An electromotive force is generated at the 23 electrodes. The generated electromotive force flows as current through the rectifier circuit 29 and the voltage control circuit 28 via the wiring (arrow B), and is stored in the capacitor 27 (see FIGS. 3 and 4). The rectifier circuit 29 rectifies the current flowing in the capacitor 27 in a constant direction even if the direction of the electromotive force changes depending on the direction of pressure applied to the piezoelectric sheet 23. Further, the electric power stored in the capacitor 27 is prevented from flowing back to the piezoelectric sheet 23. The voltage control circuit 28 prevents the capacitor 27 from being electrostatically damaged by applying a voltage exceeding the allowable range to the capacitor 27. When the amount of electricity stored in the capacitor 27 increases and its terminal voltage exceeds the terminal voltage of the secondary battery 25, current flows from the capacitor 27 to the secondary battery 25 via the charge control circuit 26, and charging is performed. The charging control circuit 26 controls the charging current so that the terminal voltage of the secondary battery 25 does not exceed a predetermined value, thereby preventing the secondary battery 25 from being overcharged. The rectifier circuit, the voltage control circuit, and the charging circuit are not particularly limited, and conventionally known ones can be used.

  Next, the second charging operation mode will be described. When the folding mechanism of the cellular phone 10 is opened and closed, the protrusion 4 provided on the upper cover 21 of the second casing 2 collides with the first piezoelectric element 8 provided on the surface of the first casing. Then, an electromotive force is generated at the electrode of the first piezoelectric element 8 due to the piezoelectric effect. The generated electromotive force flows as current through the rectifier circuit 29 and the voltage control circuit 28 via the wiring (arrow A), and is stored in the capacitor 27 in the same manner as in the first charging operation mode, and thus charged in the secondary battery 25. (See FIGS. 3 and 4). Further, in the case of this charging operation mode, the mobile phone 10 is closed without performing the opening / closing operation, and the first case and the second case are gripped strongly or the grip is loosened. In addition, since an electromotive force is generated at the electrode of the first piezoelectric element 8, the secondary battery 25 can be charged in the same manner as the aforementioned opening / closing operation.

  In the above description, lead zirconate titanate or barium titanate is given as the first piezoelectric element, and a piezoelectric sheet such as polyvinylidene fluoride is given as the second piezoelectric element. The material may be used for both. Moreover, you may use the conventionally well-known piezoelectric element which was not mentioned here.

As the portable electronic device of the present invention, a foldable mobile phone has been described as an example. Needless to say, the present invention is not limited to a foldable type, and is not limited to a mobile phone. It can be widely applied to portable electronic devices.

It is a perspective view of a mobile phone which is an example of a portable electronic device of the present invention. 3 is an exploded perspective view showing a component configuration of a second housing 2. FIG. It is a flowchart of a charge operation | movement aspect. 1 is a schematic front view of a mobile phone which is an example of a portable electronic device of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st housing | casing 2 2nd housing | casing 3 Hinge part 4 Projection part 6 Push button 7 Display part 8 1st piezoelectric element 10 Mobile phone 21 Upper cover 22 Push button sheet 23 Piezoelectric sheet (2nd piezoelectric element)
24 Lower casing 25 Secondary battery 26 Charge control circuit 27 Capacitor 28 Voltage control circuit 29 Rectifier circuit

Claims (1)

A portable electronic device comprising a rechargeable secondary battery, further comprising: a piezoelectric power generation means capable of charging the secondary battery; and a capacitor.

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