Description SMA ACTUATOR OF A CAMERA LENS BARRIER

Technical Field

[1] The present invention relates to a semi-automatic actuator (open/close device) of a camera lens barrier, and in particular to a semi-automatic SMA (Shape Memory Alloy) actuator of a camera lens barrier, which is characterized by employing the operating principal of a shape memory alloy in a driving device for controlling the opening/ closing of the camera lens barrier. Background Art

[2] In general, a hand-held small device, such as a mobile communication terminal, a camera, or the like, is formed in a pop-up configuration so that an optional component, such as a camera lens, a speaker, or the like, can be provided only when it is desired, for the purpose of compact design. In the prior art, in order to open/close a camera lens barrier, an automatic open/close method using a driving device (actuator), such as a geared motor, a solenoid, or the like, or a manual open/close method manually operating such a barrier has been employed, wherein the automatic open/close method and the manual open/close method cannot be used in combination due to the constructional features used in the methods.

[3] In particular, the automatic open/close method has problems in that if a conventional driving device, such as a geared motor or a solenoid, is employed, a final product employing such a driving device becomes complicated in construction and increased in volume, which serves as a factor limiting the compact design of the resulting device and causes the increase of material costs and maintenance expense, and in that it is impossible to employ an alternative method when the driving device is out of order.

Disclosure of Invention Technical Problem

[4] The present invention has been made so as to solve the above-mentioned problems of the prior art. The present invention provides a semi-automatic SMA (Shape Memory Alloy) actuator of a camera lens barrier employing a shape memory alloy, wherein the SMA actuator is simplified in construction and minimizes the space occupied by it while providing the same function as a conventional semi-automatic actuator, and the SMA actuator has a construction suitable for employing a semi-automatic function and a manual function in combination. Technical Solution

[5] In accordance with the present invention, there is provided an SMA (Shape

Memory Alloy) actuator of a camera lens barrier employing a shape memory alloy, the semi-automatic SMA actuator including an open/close guide unit, a base unit, a sector unit, and an open/close driving unit, wherein the open/close driving unit includes: a connection unit attached to the sector unit so as to induce the open/close movement of the sector unit by driving force; a shape memory unit, which is formed from a shape memory alloy, is extendable and retractable, and is connected to the open/close guide unit or the base unit at one side thereof and attached to the connection unit at the other side so as to transmit the driving force to the connection unit; and a restoration unit having two ends opposite to each other, which are connected to the connection unit and an anchoring member in a direction facing the shape memory unit with reference to the connection unit so as to supplement a stroke required for the open/close movement, thereby limiting the deformation of the shape memory unit.

Advantageous Effects

[6] According to one aspect of the present invention, the extension and retraction of the shape memory unit can generate sufficient driving force if and when there is an input signal for making electric current flow through the shape memory unit formed from a shape memory alloy in the form of a wire or a spring. As a result, it is possible to substantially reduce the space occupied by the semi-automatic actuator. In addition, the simplified construction and operation of the shape memory unit improve the endurance and reliability of a final product employing the unit, which is effective in reducing material costs and maintenance expense.

[7] According to another aspect of the present invention, the manual open/close operation can be easily implemented through a manual shift unit. As a result, even at an emergency situation where an automatic open/close function through an electric input signal, the open/close function can be stably implemented, which can further improve the reliability and completeness of the final product. Brief Description of the Drawings

[8] The foregoing and other objects, features and advantages of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which:

[9] FIG. 1 is an exploded perspective view of a camera lens barrier according to the present invention;

[10] FIG. 2 is a view illustrating a first construction of an open/close driving device for a camera lens barrier according to the present invention;

[11] FIG. 3 is a view showing in detail the internal assembled state of an open/close driving device of the camera lens barrier, which is configured on the basis of the construction of FIG. 2;

[12] FIG. 4 is a view illustrating a second construction of an open/close driving device for a camera lens barrier according to the present invention; and

[13] FIG. 5 is a view showing in detail the internal assembled state of an open/close driving device of the camera lens barrier, which is configured on the basis of the construction of FIG. 2. Mode for the Invention

[14] Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[15] FIG. 1 is an exploded view of an SMA actuator of a camera lens barrier according to the present invention, wherein an open/close guide unit 110, a sector unit 120, a connection unit 130, an open/close driving unit 140, a base unit 150, and a camera lens 160 are illustrated in the order from the outermost component to the innermost component.

[16] The open/close guide 110 is formed with a moving path for the sector unit 120 on the inner side thereof so as to guide the stable open/close movement of the sector unit 120, wherein the sector unit 120 performs substantial open/close movement, and the open/close guide unit 110 also serves as a housing for preventing the sector unit from being released.

[17] The sector unit 120 may be formed from one or more sectors, wherein FIG. 1 shows a sector unit formed from three sectors.

[18] The connection unit 130 is a member for interconnecting the sector unit 120 and the open/close driving unit 140 in such a manner that the sector unit 120 can receive driving force from the open/close driving unit 140. The connection unit 130 can be variously implemented. The embodiment of FIG. 1 shows a ring-shaped connection unit which receives one side of each of the three sectors so as to move the three sectors at once while rotating in a direction according to the driving force, so that the sector unit 120 including the three sectors can perform the simultaneous open/close movement, and which has an arrangement 132 to be engaged with the open/close driving unit 120. If the sector unit 120 has one single sector, it is possible to configure the connection unit 130 which is formed in a single body with the sector and projects to one side of the sector so that the connection unit 130 can be directly connected to a shape memory unit, rather than configuring the connection unit 130 in a ring shape. In addition, the connection unit is formed with a manual shift part 131 at one side thereof so as to allow the sector unit 120 to be manually moved, thereby enabling a manual open/close operation.

[19] The open/close driving unit 140 is implemented on the basis of the configuration illustrated in FIG. 2, in which a shape memory unit in the form of a spring or a wire is

engaged with the connection unit at one side of the connection unit, and a restoration unit, such as a spring, is engaged with the connection unit at the other side of the connection unit.

[20] That is, the open/close driving unit is configured in such a manner that when the shape memory unit is retracted by an input signal, thereby producing driving force, and then returned to its original position, the open/close driving unit is adapted to be prevented from moving and to be more smoothly returned to its original position by the elastic force of the restoration unit.

[21] The shape memory unit 141 may be directly connected to the connection unit 130.

Alternatively, the shape memory unit 141 may include one or more intermediate connection members 142, one side of which is connected to the shape memory unit 141, and the other side of which is connected to the restoration unit, such as a spring or a magnet, that assists the movement preventing and returning functions.

[22] A shape memory alloy employed in the present invention should be capable of assuring a fatigue life of one hundred thousand or more times of repeated deformation cycles. In order to accomplish this, it is important to limit the deformation of the shape memory alloy at the time of extending or retracting the shape memory alloy. For this purpose, it is necessary to make the restoration unit take charge of about a half of a stroke required for the open/close movement.

[23] That is, the shape memory alloy is limitedly deformed in the extending or retracting process, and the insufficient stroke caused due to this is capable of being semi- automatically implemented by providing the restoration unit. This semi-automatic implementation is substantially effective in that the endurance of the shape memory unit can be enhanced by limiting the deformation of the shape memory alloy while providing convenience in operation.

[24] In order to allow the driving force to be transmitted to the connection unit without loss, it is necessary to affix the shape memory unit 141 to a fixed member, i.e., the open/close guide unit 110 or the base unit 150 through any method, such as screwing, welding, or adhesion, at a terminal end of the shape memory unit 141 where the shape memory unit 141 is not connected to the intermediate connection members 142.

[25] In particular, the open/close driving unit 140 is adapted to be engaged with two shape memory units which have the same construction, wherein one of the shape memory units can be in charge of open movement and the other in charge of close movement, whereby the open and close velocity can be more improved. Therefore, it is possible to apply two or more open/close driving units as desired.

[26] Therefore, it is possible to additionally modify the connecting relationship between the connection unit, the shape memory unit and the restoration unit, which are the components of the open/close driving unit conceptualized in FIG. 2, by additionally

providing a component, such as an intermediate connection member. If such an additional component can be considered as an extension of the connection unit like the intermediate connection member, such modification shall be deemed as being included in the scope of the present invention.

[27] Beyond the above-mentioned embodiments, the open/close driving unit may have a construction performing the functions of the shape memory unit and the restoration unit only with the restoration force of the shape memory alloy as shown in FIG. 4. FIG. 5 shows another embodiment implemented on the basis of the construction of the open/close driving unit shown in FIG. 4, wherein a shape memory unit 241, and a restoration unit 243, each of which consists of a shape memory alloy in the form of a spring, are connected to the opposite ends of a connection unit 230, respectively. According to the present embodiment, the movement-preventing and restoration- assisting functions executed by the spring 143 as the restoration unit in the embodiment of FIGs. 2 and 3 can be implemented as the shape memory alloy placed opposite to the shape memory unit is retracted.

[28] The base unit 150 serves as a housing for fixing and protecting the individual components of the above-mentioned SMA actuator and supporting the camera lens.

[29] A camera lens 160 corresponds to a pop-up device provided while the SMA actuator according to the present invention is opened, wherein the present invention is irrespective of the type of the pop-up device because it relates to an SMA actuator of a pop-up device barrier.

[30] Therefore, the present invention can be applied to any type of a small-sized device beyond a camera lens if the device is provided to be opened or closed as desired.