1.  Field of the Invention
The present invention relates to a photo-curable adhesive composition.  More particularly, the present invention relates to a photo-curable adhesive composition suitable for use as an adhesive between metal structures and polymethylmethacrylate in electronic devices such as, e.g., an optical pick-up device, a thin film transistor-liquid crystal display (TFT-LCD), an organic electro-luminescent (EL) device, etc. 
2.  Description of the Related Art
Generally, electronic devices, e.g., optical recording/reproducing drives such as CD drives, DVD drives, blu-ray drives, etc.,  that include optical elements, may have optical elements adhered to a base.  The base may be, e.g., a metal base.  A method of securing the optical element to the base may include providing an adhesive between the optical element and the base, and then curing (hardening) the adhesive. 
Adhesives that are curable with ultraviolet light (photo-curable or UV-curable adhesives) may be used to secure an optical element to a base.  Photo-curable adhesives may exhibit various properties besides adhesion.  For example, photo-curable adhesives may be thixotropic, may provide sealing properties, may be photo- and heat-curable, etc.  Such properties may be advantageous depending on the nature of the device being manufactured and the particular manufacturing process.  Further, the cured photo-curable adhesives may exhibit a variety of material characteristics, e.g., strength, shrinkage, etc.,  that may be controlled by modifying the composition or the photo-curable adhesive and/or the application thereof. 
Moreover, adhesives may be formed from a variety of different materials, e.g., polymers of various types, and may be modified in a number of ways, e.g., through the addition of polymerization initiators and/or regulators, hydrophobic and/or hydrophilic modifiers, fillers such as inorganic fillers, thixotropic agents, etc. 
Depending on the nature of the device being manufactured and the particular manufacturing process, the absence of one or more of the above properties or characteristics may lead to a low-quality adhesive joint, distortion of the optical characteristics of the resultant electronic devices, etc.