Linear vibration motor

• US 7,235,936 B2
• Filed: 04/15/2005
• Issued: 06/26/2007
• Est. Priority Date: 04/19/2004
• Status: Active Grant

• Current Assignee: Panasonic Electric Works Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Works Ltd (Panasonic Holdings Corporation)
• Inventors: Oba, Takafumi, Takahashi, Atsushi
• Primary Examiner(s): DUDA, RINA I
• Application Number:
  US11/106,430
• Publication Number:
  US 20050231045A1
• Time in Patent Office: 802 Days
• Field of Search: 318/560, 318/3, 318/9, 318/432, 318/599, 318/811, 318/114, 318/119, 361/152, 361/154
• US Class Current: 318/114
• CPC Class Codes: H02P 25/032 Reciprocating, oscillating or vibrating motors

Abstract

A linear vibration motor comprises: a stator provided with one of a permanent magnet and an electromagnet including a winding; a vibrator provided with the other of the permanent magnet and the electromagnet and supported to be able to vibrate; a movement detection unit for detecting movement of the vibrator; a control output unit for supplying electric power to the winding of the electromagnet based on an output of the movement detection unit so as to generate vibration of the vibrator; a rechargeable battery for supplying electric power to the control output unit; and a power supply unit for supplying electric power to the control output unit and to the rechargeable battery, wherein the power supply unit supplies electric power in an intermittent mode with synchronized timing such that the timing of the intermittent power supply is synchronized with the timing of the power supply to the winding. Thereby, the voltages of the rechargeable battery for left and right outputs to the winding become the same as each other at the timing of supplying electric power to the winding for left and right outputs, preventing amplitude variation caused by difference between the voltages of the rechargeable battery, and thereby preventing amplitude fluctuations and whirring noise.

Claims

1. A linear vibration motor comprising:

a stator provided with one of a permanent magnet and an electromagnet including a winding;

a vibrator provided with the other of the permanent magnet and the electromagnet and supported to be able to vibrate;

a movement detector for detecting movement of the vibrator;

an output controller for supplying electric power to the winding of the electromagnet based on an output of the movement detector so as to generate vibration of the vibrator;

a rechargeable battery for supplying electric power to the output controller; and

a power supply for supplying electric power to the output controller and to the rechargeable battery,

wherein the power supply supplies electric power in an intermittent mode with synchronized timing such that the timing of the intermittent power supply is synchronized with the timing of the power supply to the winding.

2. The linear vibration motor according to claim 1,

wherein the output controller controls the power supply to supply the electric power in the intermittent mode with the synchronized timing.

3. The linear vibration motor according to claim 2,

wherein the movement detector detects an amplitude of the vibrator, and

wherein based upon the amplitude of the vibrator detected by the movement detector, the output controller controls the power supply to vary an amount of electric power supplied from the power supply.

4. The linear vibration motor according to claim 3,

wherein based upon the voltage of the rechargeable battery, the output controller controls the power supply to vary an amount of electric power supplied from the power supply.

5. The linear vibration motor according to claim 3,

wherein based upon a temperature of the rechargeable battery and/or the power supply, the output controller controls the power supply to vary an amount of electric power supplied from the power supply.

6. The linear vibration motor according to claim 3,

wherein the power supply varies an amount of electric power supplied therefrom by varying a pulse width of an output of the power supply.

7. The linear vibration motor according to claim 3,

wherein the power supply varies an amount of electric power supplied therefrom by varying a voltage amplitude of pulses output therefrom.

8. The linear vibration motor according to claim 3,

wherein the power supply supplies a current the same as a no-load current of the linear vibration motor.

9. The linear vibration motor according to claim 3,

wherein the power supply supplies electric power at a timing frequency which is an even multiple of a timing frequency for supplying electric power to the winding.

10. A vibration motor controller, the motor including a stator and a vibrator, one of the stator and the vibrator provided with a permanent magnet and the other of the stator and the vibrator provided with an electromagnet including a winding, the vibration motor controller comprising:

a movement detector configured to detect movement of the vibrator;

an output controller configured to supply electrical power to the winding of the electromagnet based on an output of the movement detector, so as to generate a vibration of the vibrator;

a rechargeable battery configured to supply electrical power to the output controller; and

a power supply configured to supply electrical power to the output controller and to the rechargeable battery,

wherein the power supply intermittently supplies electrical power, such that a timing of the intermittent power supply is synchronized with a timing of power supply to the winding.

11. The vibration motor controller according to claim 10, the output controller being configured to control the power supply to intermittently control electrical power with synchronized timing.

12. The vibration motor controller according to claim 11, the movement detector being configured to detect an amplitude of the vibrator, and in accordance with the detected amplitude of the vibrator, the output controller controls the power supply to vary an amount of electrical power supplied from the power supply.

13. The vibration motor controller according to claim 12, wherein the output controller controls the power supply to vary an amount of electric power supplied from the power supply in accordance with a voltage of the rechargeable battery.

14. The motor controller according to claim 12, the output controller being configured to control the power supply to vary the amount of electrical power supplied from the power supply in accordance with a temperature of one of the rechargeable battery and the power supply.

15. The motor controller, according to claim 12, the power supply being configured to vary an amount of electrical power supplied from the power supply, by varying a pulse of the power supply output.

16. The motor controller according to claim 12, the power supply being configured to vary the amount of electrical power supplied by the power supply, by varying an amplitude of voltage pulses output by the power supply.

17. The motor controller according to claim 12, the power supply being configured to supply a current that is the same as a no-load current of the motor.

18. The motor controller according to claim 12, the power supply being configured to supply electrical power at a timing frequency which is an even multiple of the timing frequency for supplying electrical power to the winding of the motor.