An advanced optoelectronic (OE) transceiver necessarily comprises semiconductor lasers, photo-detectors and electronics which are in a small package form, in order to support high speed communications. A typical transceiver module consists of multiple above-mentioned OE components which are precisely aligned to lens or lens array in sending and receiving light via external optics, like optical fiber connector. The OE component requires high precision assembly process to improve product manufacturability and to meet target cost. The inherent challenge with OE component design lies in maintaining the optical alignment between external optics and the optoelectronic emitters and receivers and product reliability. A promising optical design to overcome the challenge is using a collimator to collimate light beams. The advantage is that the mechanical alignment tolerant between optoelectronic emitters and receivers of the OE component and external optics can be relaxed. As a result, traditional expensive precision fiber connector commonly used to secure optical alignment can be avoided.
Referring to FIGS. 1-2, FIG. 1a is an illustration of a panel form package 1 includes a plurality of OE components 11 that can make collimated light beam. FIG. 1b shows an individual OE component 11, and the arrows in FIG. 1b represent the direction of the in/out optical light beams. FIG. 2 is a schematic view of a collimator set in the OE component 11. The collimator 21 is employed to convert the diverging light emitted from the laser diode 22 into parallel light beam, the size range of the collimator 21 is commonly 100-1000 um.
Traditional micro-lens manufacturing methods are deployed in making micro-lens directly onto the optoelectronic wafer or transparent substrate to integrate with the final product. With the advancement of glass material science and process control, methods including high temperature glass molding and etching the substrate made of glass or semiconductor can be used to provide micro-lens on glass substrate directly that endures high temperature assembly process such as soldering and SMT reflow process. Nevertheless, the material cost and the manufacturing cost for both technologies are considerable high. And reflowing technique fails to produce accurate collimator of larger size in meeting OE module application.
Recently, ink-jetting technology is applied to manufacture micro-lenses array onto substrate by direct dispensing. This method is made possible by combining precision volume dispensing control by either piezoelectric or micromechanical control. Although the position of micro-lens decided by ink-jetting method is with high precision, the dimension and shape of the micro-lens is in turn determined by the dispensing volume and its surface tension to reach equilibrium profile on the substrate. One of the methods for manufacturing the micro-lens is to deposit a layer onto the substrate, so a well shape pattern is left for forming the micro-lens, but the disadvantage thereof is that the edge of micro-lens is not good. Another method for manufacturing the micro-lens is dispensing liquid onto an area of the substrate so as to be wettable. That is to say, a wettable layer in a disk shape is deposited on the substrate, and the micro-lens is mounted on the layer. However, the disadvantage is that the micro-lens does not contact with the substrate directly, so the micro-lens can not be mounted on the substrate reliably, and the transparency of the micro-lens may not be so good. Furthermore, this approach has numbers of requirements on the substrate material, surface treatment, as well as the lens forming material according to its working principle. The potential application is severely limited owning to narrow range of choice of process and materials.
Accordingly, a need has arisen for providing an improved method for manufacturing polymer miniature lenses on a substrate for the collimator, to overcome the above-mentioned drawbacks.