• Edmund Optics

Scratch & Dig Standards

Edmund Optics offers Scratch & Dig Standards. These are ideal for qualifying the scratch and dig surface defects on optical components. There are 6 grids varying in size and 6 blocks of lines with varying frequencies on each plate. The grids can be used to measure the area of irregularly shaped defects. The standards are offered as sets of two plates. Plate 1 includes grade numbers ranging from 0.004 to 0.040 while Plate 2 includes 0.040 to 0.400. The first surface sets have the features marked on the top of the glass substrate. The second surface set has the features marked on the bottom of the glass substrate. The features on the positive set are opaque on a clear background. The features on the negative set are clear on an opaque background. Specifications: 60 mm scale length - 60 mm ±0.002 mm; scale divisions every 0.025 mm; substrate material soda lime float glass; thickness - 1.5 mm nominal; surface quality - 20:10; flatness - 3-4 wavelength/inch; frame material - black anodised aluminium; frame dimensions - 114.3 x 50.8 mm ±0.100 mm; angle of incidence - 45°; and line width and dot dia tolerance - plate 1 ±0.00025 mm, plate 2 ±0.0005 mm.