在大型投影仪上使用反射光工作时,被测工作物在受光屏上的影像清晰程度决定于载物工作台和被测工作物的反射光线能力的对比度的强弱。当这种对比度较弱时,影像往往较为暗淡模糊,特别是年长日久的投影仪,尤其如此,严重影响测量精度。如果在载物玻璃工作台上安放一块平面镀银镜,就能把投射过来的光线反射到受光屏上,增强受光屏的亮度和影像的对比度,有利于准确地进行 When using a reflected light on a large projector, the clarity of the image of the work-piece under test on the screen depends on the contrast of the contrast of the light reflected by the work-table and the work-piece under test. When this contrast is weak, the image is often dim and fuzzy, especially for older projectors, which can seriously affect the measurement accuracy. Placing a flat silver mirror on the load glass table reflects the projected light onto the screen and enhances the brightness of the screen and the contrast of the image,