1. Field of the Invention
The present invention relates to a method for treating the surface of an element, and more particularly, to a method using a photo-sensitive and flexible thin film to transfer a micro-structural pattern to an element having a non-planar surface.
2. Description of the Prior Art
The surface treatment of non-planar element is difficult due to its non-planar surface and the trend of miniaturization. Taking a fluid dynamic bearing as an example, the inner wall of the bearing has minute grooves with lubricant filled therein. When a shaft of a motor rotates, the lubricant filled in the grooves of the bearing will be drawn and spread all over the surface of the shaft, thereby generating a dynamic pressure. This dynamic pressure maintains the shaft in a central position of the bearing, and thus prevents friction between the shaft and the inner wall of the bearing, and restrains noises.
However, the inner wall of the bearing is a curved surface so that to form the groove disposed thereon is difficult. The grooves to be formed have extremely minute width and depth, which makes it difficult to control the accuracy. Currently, several manufacturing techniques have been proposed, such as cutting technique, rolling technique, plastic injection technique, assembling technique and machining technique after thin film process. The methods, nevertheless, are costly because each of the methods requires particular machining tools, and have some disadvantages. For example, the turning section of the grooves formed by cutter technique is sometimes discontinuous, and the depth and width of the grooves are not identical. In addition, the problems such as the expensive cost of machining equipment, the fragility of cutter, the incapability of mass production, the low tolerance of vibration of the machining environment, and the requirement of professional worker, etc, are the difficulties that the conventional fluid dynamic bearing fabrication method have to overcome.
It is therefore one of the objectives of the present invention to provide a method for treating a surface of an element to improve the high cost and inconsistent quality problems of the conventional surface treatment.
According to the present invention, a method for treating a surface of an element includes steps of: providing a photo-sensitive and flexible thin film; providing a planar photomask having a micro-structural pattern; transferring the micro-structural pattern to the thin film; providing an element having a non-planar surface; attaching the thin film having the micro-structural pattern to the non-planar surface of the element. The thin film partially exposes the non-planar surface of the element, thereby forming at least an exposed region on the non-planar surface of the element. Subsequently, at least a material layer is disposed on the thin film and on the exposed region of the non-planar surface of the element by performing a coating process. Then, the thin film and the material layer formed on the thin film are removed to form a micro-structure on the non-planar surface of the element.
According to the present invention, a method for treating a surface of an element includes steps of: providing a photo-sensitive and flexible thin film; providing a planar photomask having a micro-structural pattern; transferring the micro-structural pattern to the thin film; providing an element having non-planar surface; attaching the thin film having the micro-structural pattern to the non-planar surface of the element. The thin film partially exposes the surface of the element, thereby forming at least an exposed region on the surface of the element. Subsequently, the exposed region of the element is etched by performing an etching process, and the thin film is then removed to form a micro-structure on the non-planar surface of the element.
According to the present invention, a method for treating a surface of an element includes steps of: providing a photo-sensitive and flexible thin film; providing a planar photomask having a micro-structural pattern; transferring the micro-structural pattern to the thin film; and attaching the thin film having the micro-structural pattern to a non-planar surface of the element. The thin film partially exposes the non-planar surface of the element, thereby forming at least an exposed region on the surface of the element. Subsequently, the exposed region of the non-planar surface of the element is treated by performing a surface treatment, and the thin film is removed to form a micro-structure on the non-planar surface of the element.
The present invention uses a photo-sensitive, flexible and adhesive thin film to form a micro-structure on the non-planar surface of the element. The thin film is exposed in advance so that a micro-structural pattern is transferred from a planar photomask to the thin film, and the thin film is then attached to the non-planar surface of the element. The surface treatment such as an electroplating process or an etching process is implemented by virtue of the thin film with the micro-structural pattern.
These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings.
The present invention will become more fully understood from the detailed description given herein below and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein:
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In the aforementioned embodiment, the micro-structure is formed on the non-planar curved surface of the element by thin film techniques, and the micro-structure is made of the material layer which protrudes out of the curved surface of the element. The method of the present invention is not limited by the above embodiment. Please refer to
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The method for treating a surface of an element of the present invention can be applied to form various types of elements having a non-planar surface such as a fluid dynamic bearing. In the aforementioned embodiments, an element having cylindrical tubal structure is used as an example and the micro-structure is formed on the outer surface (curved surface) of the cylindrical tubal element. However, the method of the present invention can also be applied to the inner surface of element and a three-dimensional element having various kinds of shapes e.g. a cylindrical structure or a cubic structure.
The present invention uses a photo-sensitive, flexible and adhesive thin film to fabricate a micro-structure on a non-planar surface of element. The thin film is exposed in advance so that a micro-structural pattern is transferred from a planar photomask to the thin film, and the thin film is attached to the non-planar surface of the element. The surface treatment is implemented by virtue of the thin film with the micro-structural pattern. Compared with the conventional method, the method of the present invention is advantageous for its high efficiency, low cost and high applicability.
Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention.
Number | Date | Country | Kind |
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096141535 | Nov 2007 | TW | national |