1. Field of the Invention
The present invention relates to a linear vibrator.
2. Description of the Related Art
In recent years, a personal mobile terminal having a large liquid crystal display (LCD) screen for a user's convenience has been increasingly released onto the market. In line with this trend, a touch screen type display device has been greatly favored, and a vibration motor has been used so as to generate vibrations when a touch is applied to a touch screen.
A vibration motor transforms electrical energy into mechanical energy using a principle of generating electromagnetic force, is mounted on a personal mobile terminal, and is used for silent call reception notification.
According to the related art, rotatory power is generated to rotate a rotational part of an unbalance mass, thereby obtaining mechanical vibrations. In this case, rotatory power is generated such that it is subjected to a rectifying action through a brush and a contact point of a commutator (or rectifier) to obtain mechanical vibrations.
However, in the brush type structure using a commutator, when the motor rotates, the brush passes through a gap between segments of the commutator, causing mechanical friction and an electrical spark, producing foreign objects and thereby shortening the life span of the motor.
In addition, because voltage is applied to the motor by using a moment of inertia, time is taken to reach a target amount of vibrations, so it is difficult to implement vibrations suitable for a touch screen.
In order to overcome such disadvantages in terms of the life span and response of the motor and implement the vibration function of the touch screen, a linear vibrator is increasingly being used.
A linear vibrator, rather than using the rotational principle of the motor, uses the following principle: when electromagnetic force, obtained by using a spring installed inside a vibration motor and a mass body hung on the spring, is generated periodically in conformity with a resonance frequency, resonance is caused, thereby generating vibrations.
The linear vibrator needs to be slimmed and efficiently produced in order to meet a market trend in which miniaturization and slimness of portable electronic devices are demanded, while performance and characteristics thereof should not be affected, even in the case that several different factors are applied.
In particular, a linear vibrator mounted in an internal space of a housing largely has a vibrating part and a fixed part, wherein the fixed part is fixed to the housing and the vibrating part is vibrated through electromagnetic interaction with the fixed part. In this configuration, the fixed part, fixed to the housing, may be separated from the housing due to an external shock, or the like, applied to the linear vibrator.
Patent Document 1 discloses that fixed parts, that is, a yoke 15 and a coil 14 are fixed to a bracket 11 and only one end thereof is fixed to the bracket 11 and therefore, the yoke 15 may be separated from the bracket 11 when an external shock, or the like, is applied thereto.