Segmentation by type distinguishes four principal chemistries that dominate the Optical Encapsulation Adhesive market. UV‑curable systems, characterized by rapid polymerization under 365 nm light, command approximately 45 % of revenue because they enable inline processing and minimal thermal load on sensitive photonic components. Thermally curable adhesives, typically epoxy‑based, account for 30 % of sales; their superior mechanical strength and high‑temperature resistance suit high‑power laser modules and aerospace optics. Silicone‑based adhesives, contributing 15 %, are valued for flexibility and low‑modulus behavior, making them the preferred choice for rugged sensor housings and medical‑device enclosures where vibration damping is essential. Epoxy‑modified hybrids, representing the remaining 10 %, blend the adhesion strength of epoxies with the optical clarity of UV systems, supporting emerging PIC packaging that demands both low insertion loss and robust environmental sealing. This type‑centric market taxonomy highlights how performance criteria—curing speed, thermal tolerance, elasticity, and optical loss—directly influence each chemistry’s share of the total market.