Repair of damaged lens surface of CPV using silica based coating

We tried to repair the surface of damaged polymethyl methacrylate and glass using a simple coating and evaluated the transmittance of direct component of light. We coated a repairing material on the surface of the sample. After the 1st sandblasting, the transmittance and the calculated conversion efficiency of CPV decreased due to the damage derived by the sand. However, after the 1st coating, they made a recovery due to the effect of the repairing coating. In the second steps (sandblasting and coating), the recovery was also observed. Instead of replacement of damaged lens or module, the coating can bring the performance back into good condition.