10.0 MTF Graph and its Discussion

Figure 4: Typical MTF vs. Distance

TYPICAL MTF VS DEPTH OF FOCUS

0

10

20

30

40

50

60

0

0.2

0.4

0.6

DEPTH FROM THE WINDOW SURFACE(mm)

This graph essentially shows the working depth-of-focus. Two curves indicate the spread among the modules. Note that MTF is greater

than 40 percent out to a distance greater than 0.4mm from the glass surface. Since this module is a 200dpi module, a pixel density of

200 pixels per inch, the MTF was measured with a 100dpi or a 50 line-pair per inch optical bar pattern. The test was conducted with

the pixel rate set to 2.5MHz.

The effective algorithm used in the measurements is as described by the following equation:

MTF={[Vp(n)+Vp(n+1)]/2-[Vp(n+2)+Vp(n+3)]/2}/{[Vp(n)+Vp(n+1)]/2+[Vp(n+2)+Vp(n+3)]/2}

Where n is 1, 2, .....1728

Where n is 1, 2, .....1728

10

AMI Semiconductor – May 06, M-20548-001

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