1. Technical Field
The present disclosure relates to optical imaging, and particularly to a mold for fabricating concave lenses, which is used in press-molding.
2. Description of Related Art
Camera modules are widely used in portable electronic devices (e.g., mobile phones). Lenses used in the camera modules of the portable electronic devices are conventionally made by injection molding. Thicknesses of the lenses made by injection molding are usually more than 0.3 millimeters.
Nowadays, the portable electronic devices have become more light-weight, and smaller in volume. Generally, a thickness of the portable electronic device is limited by a height of a camera module received in the portable electronic device. In order to meet the requirement of light-weight and small in volume, sizes of the camera modules and the lenses of the camera modules need to be relatively small. However, it is difficult to produce small lenses with a thickness less than 0.3 millimeters using injection mold.
Therefore, a new mold is desired to overcome the above-mentioned problems.
Many aspects of the embodiments can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present embodiments. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.
Embodiments will now be described in detail below with reference to the drawings.
Referring to
The molding cavities 206 are arranged in a matrix of rows and columns. In the exemplary embodiment, each molding cavity 206 is circular in cross-section. In alternative embodiments, each molding cavity 206 can be other shapes, for example, rectangular. Each molding cavity 206 is defined by a respective convex molding surface 208 and a side surface 209 connected with the convex molding surface 208. Each convex molding surface 208 is positioned between the first surface 202 and the second surface 204, and is entirely received in a corresponding molding cavity 206. A maximum distance between the convex molding surface 208 and the first surface 202 is less than a thickness of the base 200. A minimum distance between the convex molding surface 208 and the second surface 204 is in an approximate range from 1 micron to 300 microns, and particularly, in an approximate range from 100 microns to 200 microns.
In the exemplary embodiment, the side surface 209 is perpendicular to the second surface 204. It should be noted that in alternative embodiments, the side surface 209 can be inclined relative to the second surface 204.
In the present embodiment, each convex molding surface 208 is a spherical surface. It is to be understood that in other embodiments, each convex molding surface 208 can be an aspherical surface.
The mold is made of the material selected from the group consisting of metal, silicon, and polydimethylsiloxane (PDMS).
An exemplary method for fabricating a lens array using the mold 20 will be described below:
In step 1, referring to
In step 2, referring to
In step 3, the press-molded blobs 40 are solidified by, e.g., ultraviolet irradiation to form a lens array, which includes a plurality of lenses 70 arranged in a matrix of rows and columns.
In step 4, referring to
In the above exemplary method, the present mold 20 is used to produce the lenses 70 in press-molding using wafer-level techniques. Accordingly, the lens 70 has a small size, so camera modules (not shown) employing the lenses 70 are correspondingly small. Therefore, the lens 70 meets the miniaturization requirement of camera modules.
Furthermore, in the above exemplary method, since the molding cavities 206 are defined in the second surface 204, most/all of the optical material 70 is restricted in the molding cavities 206. Hence, little or none of the optical material 70 leaks from the molding cavities 206. Accordingly, less or none of the optical material 70 is wasted.
It is to be understood that in other methods, only a large blob 40 of the optical material is deposited on a surface 51 of the substrate 50 in step 1. Therefore, a lens array made by such method includes a plurality of connecting parts (not shown) formed between adjacent lenses 70. Accordingly, after the lens array is done, the lens array is cut into a plurality of individual lenses 70.
While certain embodiments have been described and exemplified above, various other embodiments from the foregoing disclosure will be apparent to those skilled in the art. The present invention is not limited to the particular embodiments described and exemplified but is capable of considerable variation and modification without departure from the scope and the spirit of the appended claims.
Number | Date | Country | Kind |
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200910302321.6 | May 2009 | CN | national |