Half-Ball (hemispherical) lenses have a good performance on microscopy, endoscopy, fiber communication, optical pick-up devices, and laser measurement systems, LED industry, especially for high power and UV LED. Half balls are with much more advantages than silicone lenses and plastic lenses. Yutai Optics offers a lot of half balls to European and American customers, the material range from BK7, fused silica, sapphire and ruby, as well as other optical glass.We may have some similar stock half balls for your project.