越南采购需求：目镜标尺、显微镜标尺、光学标尺、标尺、标尺网格、标尺线

We are looking for a high-quality optical component with the following specifications: dimensions should be 400 mm x 400 mm x 15 mm or larger. The preferred material is fused silica or quartz, with low thermal expansion characteristics being ideal. The component must meet a flatness tolerance of ≤ 5 µm, ideally achieving λ/20 or better. For surface quality, we require a standard of 60-40 or higher. Additionally, we need the parallelism to be ≤ 30 arc seconds if feasible. The initial order will be for 1 unit, which will be used for evaluation purposes. Please deliver the product to our location in Vietnam. It is essential that you provide us with an interferogram or flatness inspection report along with the product to verify its quality.