Optical module comprising lens assembly

Abstract

In one example, an apparatus comprises: a lens assembly comprising one or more polymer layers, each layer including a lens portion and an extension portion and an image sensor positioned below the lens assembly and bonded to the lens assembly via a bonding layer and configured to sense light that passes through the lens portion of the one or more polymer layers.

What is claimed is: 
     
         1 . A method, comprising:
 forming a lens assembly comprising one or more lenses;   performing a reflow process to conductively bond an image sensor onto a printed circuit board (PCB) to form an image sensor stack;   forming a layer of adhesive on at least one of the image sensor stack or the lens assembly;   connecting the lens assembly and the image sensor stack via the layer of adhesive;   moving at least one of the lens assembly or the image sensor stack to align the image sensor with the one or more lenses; and   with the image sensor stack and the lens assembly at their respective aligned positions and orientations, curing the layer of adhesive to bond the image sensor stack with the lens assembly.   
     
     
         2 . The method of  claim 1 , wherein forming the lens assembly comprises fabricating each of the one or more lenses using a mold-injection process. 
     
     
         3 . The method of  claim 1 , wherein the one or more lenses comprise a plurality of lenses;
 and wherein forming the lens assembly comprises:
 stacking the plurality of lenses with a plurality of spacers to form a lens stack, wherein each pair of lens of the plurality of lenses is separated by a spacer of the plurality of spacers in the lens stack. 
   
     
     
         4 . The method of  claim 3 , wherein the plurality of spacers are formed using a mold-injection process. 
     
     
         5 . The method of  claim 3 , further comprising coating four sides of the lens stack with an opaque material. 
     
     
         6 . The method of  claim 3 , wherein the plurality of spacers are made of an opaque material comprising one of: a polymer or a metal. 
     
     
         7 . The method of  claim 1 , further comprising:
 fabricating an image sensor die;   packaging the image sensor die in a flip-chip package;   depositing solder balls on the flip-chip package; and   bringing the flip-chip packages having the solder balls into contact with contact pads of the PCB,   wherein the reflow process is performed to reflow the solder balls of the flip-chip packages into a liquid state to form conductive bonds with the contact pads.   
     
     
         8 . The method of  claim 7 , further comprising: forming a glass substrate on a light receiving surface of the image sensor die. 
     
     
         9 . The method of  claim 8 , wherein the layer of adhesive is formed on a perimeter of the glass substrate. 
     
     
         10 . The method of  claim 8 , wherein the lens assembly further comprises a light outputting surface; and
 wherein the layer of adhesive is distributed on a region of glass substrate to bond with the light outputting surface.   
     
     
         11 . The method of  claim 1 , wherein moving at least one of the lens assembly or the image sensor stack to align the image sensor with the one or more lenses comprises:
 controlling the image sensor to generate sensor data of light received by the image sensor via the one or more lenses;   determining a degree of alignment between the image sensor and the one or more lenses based on the sensor data; and   moving at least one of the lens assembly or the image sensor stack based on the degree of alignment.   
     
     
         12 . The method of  claim 11 , wherein a footprint of the lens assembly is substantially identical to a footprint of the image sensor. 
     
     
         13 . The method of  claim 1 , wherein the curing the layer of adhesive comprises subjecting the layer of adhesive to ultra-violet light. 
     
     
         14 . The method of  claim 1 , wherein the curing the layer of adhesive comprises subjecting the layer of adhesive to a heat process at a temperature lower than the melting point of the one or more lenses. 
     
     
         15 . The method of  claim 1 , wherein the adhesive is opaque or has a low light transmittance upon hardening by the curing of the adhesive. 
     
     
         16 . The method of  claim 1 , further comprising fabricating a housing to hold the one or more lenses. 
     
     
         17 . The method of  claim 16 , wherein the one or more lenses comprise a plurality of lenses;
 and wherein forming the lens assembly comprises:
 stacking the plurality of lenses with a plurality of spacers to form a lens stack, wherein each pair of lens of the plurality of lenses is separated by a spacer of the plurality of spacers in the lens stack; and 
 inserting the lens stack into the housing to form the lens assembly. 
   
     
     
         18 . The method of  claim 17 , further comprising mounting a retainer to the housing to secure the lens assembly, wherein the image sensor is bonded to either the housing or the retainer. 
     
     
         19 . The method of  claim 1 , wherein the one or more lenses comprise a polymer material. 
     
     
         20 . The method of  claim 19 , wherein the polymer material comprises a cyclo olefin copolymer (COC) material.