Description of Sinusoidal MTF Target in HEBS-glass

CMI Sinusoidal MTF Target, shown in diagram below, includes 21 sinusoidal transmittance patterns. Sinusoidal transmittance patterns are designed specifically for evaluating the MTF of imaging lenses and other optical components. MTF analysis is needed in evaluating system components to confirm that they meet design and performance specifications. The sinusoidal target is used to determine MTF or the image quality information over a full range of spatial frequencies. The spatial frequencies in the 21 sinusoidal transmittance patterns are 2, 4, 6, 8, 10, 12, 16, 20, 28, 40, 50, 66, 80, 100, 125, 133, 166, 200, 250, 400, and 500 periods per mm. 14 reference optical density patches are also included in the test target; the optical density values in the uniform optical density patches are: 0.2, 0.25, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 1.0, 1.2, 1.4, 1.6, 1.8, and 2.0. The Sinusoidal MTF Target in a HEBS-glass plate is fabricated with a number of gray scale levels using an electron beam pattern generator using 0.1 micron write grid; for example, the sinusoidal pattern at 2 cycles/mm is constructed with 100 gray scale levels, the transmittance values of the 100 gray levels are: T = 0.0102 + 0.3024*[sin((2pi/100)*i)+1]; where i = 1,2,...,100. This MTF Target having smooth and continuous transmittance profiles of sine waves, has no graininess and is less expensive than other commercially available products of much less quality.

Photos 1 and 2 (Photo a at 1000x, Photo b at 400x) exhibit a sinusoidal transmittance grating of 80 cycles per mm in a HEBS-glass plate and in a high-resolution photographic emulsion plate, respectively. Whereas the transmittance profile is smooth and continuous in a HEBS-glass plate (See Photo 1A and 1B), the transmittance profile is rough and not continuous in a high-resolution photographic emulsion plate (See Photo 2A and 2B) due to the graininess of an emulsion plate.

Detailed specifications and layout are exhibited below: