Patent Application
20120027978
1. Field of the Invention
The present invention relates to optical substrate technology and more particularly, to a multi-element optical substrate and its preparation method. The invention relates also to an optical module using the multi-element optical substrate.
2. Description of the Related Art
Normally, an optical substrate has its function block located on the center area, and its border area used for mounting or decoration purpose. Using one single expensive material to make an optical substrate, the manufacturing cost will be high. There, multi-element optical substrates are developed.
However, when molding one element on another element to form a multi-element optical substrate, due to the existence of mold member precision tolerance, the two elements may not have the same optical center. Thus, when one element of a multi-element optical substrate is used for position calibration during installation, the optical center of the second element will not be accurately positioned, lowering the optical performance.
Therefore it is desirable to provide a multi-element optical substrate preparation method that eliminates the aforesaid problem.
The present invention has been accomplished under the circumstances in view. It is the main object of the present invention to provide a multi-element optical substrate and its preparation method, which enables a predetermined part of a first element to work as a positioning reference, and then mold a second element on the first element to have the optical center of the second element to be accurately obtained subject to the positioning reference so that an accurate optical center alignment effect can be obtained when the multi-element optical substrate is assembled with other components.
To achieve this and other objects of the present invention, a multi-element optical substrate preparation method includes the steps of: a) preparing a first element having a center hole and a core positioning device defining a first element center line; b) preparing a mold having a mold cavity and a cavity center line, and then placing the first element in the mold to keep a predetermined part of the first element in contact with the mold cavity; c) calibrating the position of the core positioning device of the first element in the mold cavity subject to the reference of the cavity center line of the mold; d) filling a transparent plastic material into the mold cavity of the mold for enabling the transparent plastic material to be molded on the first element and cured into a second element so that the first element and the second element form an optical substrate; and e) opening the mold and taking the optical substrate out of the mold.
The invention also provides a lens module having installed therein a multi-element optical substrate prepared according to the aforesaid preparation method.
To achieve this and other objects of the present invention, a multi-element optical substrate comprises a first element having a center hole and a core positioning device defining a first element center line. And a second element molded on the first element and connected to the center hole of the first element. The second element defines a second element center line that is determined subject to the reference of the core positioning device of the first element.
The advantages and features of the present invention will be understood by reference to the following specification in conjunction with the accompanying drawings, in which like reference signs denote like elements of structure, in which, please refer to
a) preparing a first element 10 that has a bottom wall 15, a top wall 16, a center hole 11 cut through the top and bottom walls 15;16, an outer race 13 that forms a core positioning device defining a first element center line L1, and an inner race 14;
b) preparing a mold M having a mold cavity M0 and a cavity center line L0, and then placing the first element 10 in the mold M to keep a predetermined part of the first element 10 in contact with the mold cavity M0;
c) calibrating the position of the core positioning device of the first element 10 in the mold cavity M0 subject to the reference of the cavity center line L0 of the mold M by using a core positioning tool C;
d) filling a transparent plastic material 20M into the mold cavity M0 of the mold M for enabling the transparent plastic material 20M to be molded on the first element 10 and cured into a second element 20 so that the first element 10 and the second element 20 form an optical substrate 1, wherein filling of the transparent plastic material 20M can be achieved by spot-gluing, injection or extrusion; wherein the second element 20 and the first element 10 are joined together in a butt joint manner; wherein the transparent plastic material 20M is a light-curing or cold-curing material; and
e) opening the mold M and taking the optical substrate 1 out of the mold M.
According to this first embodiment, the center line L1 of the first element 10 is coincided with the cavity center line L0 of the mold M.
Based on the aforesaid steps, the invention provides an optical substrate 1, comprising a first element 10 and a second element 20. The second element 20 comprises a first element connection portion 24, a bottom wall 25 and a top wall 26. The bottom wall 25 and the top wall 26 define a second element's center line L2 that is coincided with the center line L1 of the first element 10.
Thus, when the outer race 13 of the first element 10 is fastened to another component (for example, lens module), the second element's center line L2 of the second element 20 is accurately kept in axial alignment with the axis to be set, assuring an accurate optical projection effect.
Referring to
Further, when calibrating the position of the first element center line L1 based on the cavity center line L0 of the mold MA, the core positioning tool C is positioned on the inner race 14A of the first element 10A. It is to be understood that the core positioning device can be positioned on the outer race 13A (not shown) as the aforesaid first step, or positioned on both the outer race and the inner race.
Further, the mold cavity of the mold MB is located on the second mold member M2B, facilitating positioning and/or molding.
Referring to
According to this third embodiment, the periphery 32B of the peripheral cover member 30B of the first element 10B works as the core positioning device to have the center axis of the first element 10B be positioned on the device at the peripheral cover member 30B.
Further, the cavity center line L0 for calibrating the position of the second element's center line L2 is disposed in parallel to the first element center line L1, thus, another multi-element optical substrate is obtained where the second element's center line L2 can be accurately positioned relative to the first element center line L1.
Further, the mold MB in accordance with this third embodiment has an added more core M3B.
In conclusion, based on the aforesaid preparation methods, a multi-element optical substrate comprises:
a first element 10;10A;10B, having a center hole 11 and a core positioning device that defines a first element center line L1; and
a second element 20;20A;20B connected to the center hole 11 of the first element 10;10A;10B and cured and bonded to the first element 10;10A;10B;
wherein the second element's center line L2 is determined subject to the reference of the core positioning device of the first element 10;10A;10B.
Further, the invention provides a lens module 100 having installed therein a multi-element optical substrate 1C, wherein the first element 10C of the multi-element optical substrate 1C is mounted in the lens barrel of the lens module in front of other lens elements of the lens module; the second element 20C is in axial alignment with an aperture of the lens barrel, as shown in
The above described embodiments are simple examples of the present invention. The preparation steps, materials used and structures of elements may be alternatively changed. Further, each of the aforesaid embodiments may be modified subject to the following modifications and their combinations.
At first, except having an outer race and an inner race, the first element has its inner race to work as the core positioning device.
Thereafter, the filling of the plastic material can be achieved by means of spot-gluing, injection or extrusion.
Further, except that the second element must be prepared from a light transmission material, the first element can be prepared from a light transmission material, a translucent material or an opaque material. Thus, invention facilitates material selection, saving the cost. When a translucent or opaque material is used for the first element, the material provides a light shielding effect. Further, the first element and the second element can be prepared from glass, or temperature-resistant resin that resists temperature 300˜500° C. and can be made by means of injection molding.
Further, the second element can be a convex lens or concave lens.
Further, the cavity center line of the mold and the center line of the first element can be coincided with each other, arranged in a parallel manner, or tiled relative to each other to define a contained angle.
Further, the center line of the second element and the center line of the first element can be coincided with each other, arranged in a parallel manner, or tiled relative to each other to define a contained angle.
In general, the present invention having been thus described with particular reference to the preferred embodiments thereof, it will be understood that in a multi-element optical substrate and its preparation method according to the present invention, a predetermined part of a first element works as a positioning reference, a second element is formed and bonded to the first element to have the optical center of the second element be accurately obtained subject to the positioning reference of the first element. Thus, after installation of the multi-element optical substrate in another component, an accurate optical center alignment effect is obtained.
Although particular embodiments of the invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.
