Processing Procedure for Optical Glass Prisms

The processing workflow of optical glass prisms is a precise and complex process. This article will introduce the key steps in the processing workflow of optical glass prisms.

Raw Material Preparation

First, a piece of glass blank that meets specific grade and glass type is needed. These blank materials typically possess excellent optical performance and mechanical stability, such as K9 glass and UV fused silica.

Rough Grinding (Cutting)

Rough grinding is the first step in the processing of optical glass prisms, aiming to give the glass blank a basic geometric shape and size. This process is usually carried out using grinding machines or metal diamond wheels to remove a large amount of glass material, bringing the prism's size close to the desired specifications. After rough grinding, the prism's surface will have relatively rough marks and an uneven layer.

Fine Grinding

Fine grinding further refines the surface of the optical glass prism following rough grinding. The main goal at this stage is to remove the subsurface cracks and scratches left during rough grinding, enhancing surface uniformity and smoothness. During fine grinding, the surface of the optical glass prism must remain wet to accelerate the removal rate and prevent glass from overheating. After fine grinding, the prism surface should become relatively smooth but still not meet the final optical precision requirements.

Polishing

Polishing is one of the most critical steps in optical glass prism processing, determining the final optical quality of the prism. During polishing, the prism surface is rubbed against polishing tools like a polyurethane polisher wetted with "lapping slurry" to remove the fine marks and uneven layers left from fine grinding. Polishing slurries commonly contain mixtures of water and optical polishing compounds like pumice or cerium oxide. The polishing process requires strict control of time, pressure, temperature, and input amount of the polishing agent to ensure the surface of the optical glass prism meets the specified optical precision and smoothness.

Chamfering

After polishing, the edges of the optical glass prism are chamfered using a rotating diamond plate. This step aims to slightly blunt the sharp edges of the prism to prevent it from scratching or damaging other optical components during use. After chamfering, the prism's edges become smooth and less likely to cause damage.

Cleaning and Inspection

Before coating, the prism needs to be thoroughly cleaned to remove surface impurities and contaminants. After cleaning, the glass prism undergoes optical testing and visual inspection to ensure its surface quality, dimensional accuracy, and optical performance meet design requirements. These inspections can be carried out manually or automatically.

Coating

Depending on the requirements, the surface of the prism may be coated with anti-reflection (AR) coatings or reflective coatings (such as metal coatings) to enhance its transmittance or reflectance. The coating process usually takes place in a vacuum environment, using methods like evaporation or sputtering to deposit the coating material on the surface of the optical glass prism. After coating, the optical performance of the prism will be further improved.

Packaging and Shipping

Finally, glass prisms for sale that have passed strict inspection and testing will be organized, packaged, and shipped. During packaging, special attention must be paid to protecting the prism surface from scratches and contamination to ensure it maintains good optical performance during use.

In conclusion, the processing workflow of optical glass prisms includes several key steps such as raw material preparation, rough grinding, fine grinding, polishing, chamfering, cleaning and inspection, coating, and packaging and shipping. Each step requires strict control of process parameters and quality requirements to ensure the final product's optical performance and reliability.