SAME

Technical Field An exemplary embodiment of the present invention relates to a spring manufacturing method and a spring using the same. More particularly, an exemplary embodiment of the present invention relates to a method of manufacturing a spring adopted in a sliding type-hinge device of a portable terminal and a spring using the same. Background Art

In general, portable terminals such as a cellular phone, a PDA, a notebook, a DMB phone, etc. are widely used in order to wirelessly use communication and broadcasting services while moving rather than at a fixed position. With the advent of an information-oriented era, portable terminals are one of necessities that are essential for enjoying life convenience. In particular, the cellular phone is very widely spread to elementary, middle, and high school students, as well as to the elderly.

Various methods to open and close a cover are applied to the portable terminal. Various types thereof may be generally classified into a hinge type, a sliding type, and a swing type.

Among them, since the portable terminal that opens and closes the cover as the sliding type has various merits such as user convenience, a low failure rate, and an elegant design, the sliding type has been one of the most applied types in recent years.

In a basic structure of the portable terminal of which the cover is opened and closed as the sliding type, the cover having the display part installed thereon slides upward and downward from the main body having the keypad, etc. installed therein. The upward and downward sliding of the cover is implemented by a sliding-type hinge device. Such a sliding-type hinge device is manufactured in various structures by manufacturers. An example of a sliding-type hinge device according to the prior art basically includes a guide member that is fixed to a main body, a movable member that is fixed to a cover and is slidably joined to the guide member, and a spring of which both ends are rotatably coupled to the movable member and the guide member.

Accordingly, in the prior art, in a state in which the cover of the portable terminal is opened or closed, a user applies force to the cover until the movable member slides to the guide member for a predetermined section, such that the spring is compressed or loosened by relative movement of the movable member and the guide member.

At this time, elastic restoration force of the spring is provided to the movable member and the guide member, such that the movable member automatically slides in accordance with the opening or closing of the cover by the elastic restoration force of the spring in the remaining section. Meanwhile, in the sliding-type hinge device of a portable terminal according to the prior art, the spring may be classified into a circular cross- sectional and strip-shaped torsion types and wave types that have a predetermined width and a predetermined thickness.

In this case, the spring having the circular cross-section is formed by coiling and bending processes, and the strip shaped spring is formed by a bending process.

However, in the prior art, when the spring having the circular cross- section is adopted in the sliding-type hinge device, a thickness of the entire device becomes relatively larger due to a circular diameter thereof. Further, in the prior art, when the strip-shaped spring is adopted in the sliding-type hinge device, the thickness of the entire device may become smaller, but it is complicated to manufacture the spring and it is not easy to process the spring in an accurate size.

The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art. DETAILED DESCRIPTION Technical Problem

The present invention has been made in an effort to provide a spring manufacturing method that is capable of manufacturing a strip-shaped spring by a photo-etching process, and a spring using the same. Technical Solution

An exemplary embodiment of the present invention provides a spring manufacturing method that includes: i) a first step of preparing an original metal plate cut to a predetermined size; ii) a second step of coating both surfaces of the original metal plate with a photosensitive photoresist; iii) a third step of forming a spring pattern part having a predetermined shape by vacuum-contacting a photomask to the original metal plate coated with the photosensitive photoresist and irradiating UV rays to the original metal plate; iv) a fourth step of removing the photosensitive photoresist of a non- pattern part except for the spring pattern part; and v) a fifth step of etching the non-pattern part with an etching solution.

In the spring manufacturing method, after the first step, the original metal plate may be cleaned.

In the spring manufacturing method, the original metal plate may be made of any material selected from a group consisting of a copper alloy, a nickel alloy, and stainless steel (SUS).

In the spring manufacturing method, in the fifth step, ferric chloride (FeCB) may be used as the etching solution.

In the spring manufacturing method, after the fifth step, a spring corresponding to the spring pattern part is completed by removing the photosensitive photoresist of the spring pattern part, and the spring is then washed.

In the spring manufacturing method, after washing the spring, the spring may be heat-treated. Another embodiment of the present invention provides a spring having a cross-section of a predetermined width and a predetermined thickness, which is manufactured by the spring manufacturing method of the first to fifth steps.

Brief Description of the Drawings

Exemplary embodiments of the present invention are described with reference to the accompanying drawings, and thus the spirit of the present invention is not limited to the accompanying drawings.

FIG. 1 is a schematic plan view of a spring according to an exemplary embodiment of the present invention.

FIG. 2 is a flowchart for illustrating a spring manufacturing method according to an exemplary embodiment of the present invention. FIGS. 3 to 8 are schematic plan views schematically illustrating each of steps of FIG. 2. Best Mode

The present invention will be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

FIG. 1 is a schematic plan view of a spring according to an exemplary embodiment of the present invention. Referring to FIG. 1, an example of a spring 100 according to an exemplary embodiment of the present invention may include a torsion-type spring (refer to FIG. IA) and a wave-type spring (refer to FIG. IB) that have a predetermined width and a predetermined thickness, and have a strip shape.

Herein, the spring 100 may be adopted in a sliding- type hinge device for allowing a cover to slide to a main body in a vertical direction in a portable terminal, i.e., a cellular phone.

However, the exemplary embodiment of the present invention is not particularly limited to only the sliding-type hinge device of the portable terminal such as the general cellular phone, but it may be adopted in a sliding-type hinge device of mobile communication terminals such as a PDA phone, a DMB phone, etc.

FIG. 2 is a flowchart for illustrating a spring manufacturing method according to an exemplary embodiment of the present invention.

Referring to the figure, the spring manufacturing method according to an exemplary embodiment of the present invention includes preparing an original metal plate (SlO), performing photoresist coating (S20), performing exposure (S30), performing development (S40), and performing etching (S50). Each of the steps will be described with reference to FIGS. 3 to 8. In step SlO, as shown in FIG. 3, an original metal plate 11 is prepared, which is cut to a predetermined size from a metal plate raw material in a coil or sheet state.

The original metal plate 11 is made of a copper alloy, a nickel alloy, or stainless steel (SUS). In the exemplary embodiment, the original metal plate 11 is preferably made of stainless steel (SUS).

In this case, the metal plate raw material is represented by a raw material that is subjected to general heat treatment such as tempering, annealing, quenching, etc.

In step SlO, a pretreatment process to clean fat and oil contents that are electro-deposited on a surface of the original metal plate 11 by means of alkali surface treatment chemicals is performed.

Further, in the pretreatment process, sub-processes such as fat removal, flushing, pickling, drying, and exporting of the original metal plate 11 are further performed. In step S20, as shown in FIG. 4, both surfaces of the original metal plate 11 are coated with photoresist 21.

Herein, the photosensitive photoresist 21 is composed of a dry film that can be closely coated on top and bottom surfaces of the original metal plate 11. In step S30, as shown in FIG. 5, the original metal plate 11 coated with the photosensitive photoresist 21 is exposed. First, a photomask 31 comes into vacuum contact with the original metal plate 11.

In this state, a spring pattern part 33 corresponding to a predetermined shape, that is, a spring form shown in FIG. 1, is formed by irradiating UV rays to the original metal plate 11.

In this case, since an exposure amount of the UV rays is determined in accordance with the type of the photosensitive photoresist 21 and the size of the result (spring), the exposure amount is not particularly limited to a predetermined value. In step S40, as shown in FIG. 6, the developing process to remove the photosensitive photoresist 21 of a non-pattern part 41 except for the spring pattern part 33 is performed.

Therefore, only the photosensitive photoresist 21 corresponding to the spring pattern part 33 remains on both surfaces of the original metal plate 11.

Thereafter, in step S50, as shown in FIG. 7, a part of the original metal plate 11 except for the spring pattern part 33 is corroded by etching the non- pattern part 41 with an etching solution, such that the non-pattern part 41 is removed. Herein, ferric chloride (FeCB) is preferably used as the etching solution. Since the concentration and temperature conditions of the etching solution are determined in accordance with the type of material of the original metal plate 11, the concentration and temperature conditions of the etching solution are not limited to predetermined values in the exemplary embodiment.

A post treatment process is performed after the above-described processes. The spring 100 corresponding to the spring pattern part 33 is completed as shown in FIG. 8 by removing the photosensitive photoresist 21 of the spring pattern part 33 shown in FIG. 7. Thereafter, when the size of the spring 100 is measured and the spring 100 is examined in a state in which the spring 100 is heat-treated at a predetermined temperature after being washed, manufacturing of the spring 100 according to an exemplary embodiment of the present invention is completed. In this case, in the heat treatment process of the spring 100, a tempering process is performed in order to remove stress remaining in the spring 100. For example, when the spring 100 is made of stainless steel (SUS), the spring is preferably heat-treated at a temperature range of 150 to 440 C for 15 minutes to 2 hours during this process. Accordingly, the spring 100 according to an exemplary embodiment of the present invention has a predetermined width and a predetermined thickness and has a strip shape through the above-described photo-etching processes. The spring 100 is manufactured as the torsion- type spring or the wave- type spring shown in FIG. 1. Therefore, unlike the prior art in which a spring is manufactured by mechanically bending a metal plate, in the exemplary embodiment, since a strip-shaped spring can be manufactured through photo-etching, the spring can be processed with a precise size in accordance with a written examination standard and the spring can be more easily mass-produced. While this invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.