MTF Graph and Its Discussion

See Figure 4 MTF versus Distance. This graph essentially shows the working depth of

focus. Since this module is a 300DPI module, a pixel density of 300 pixel per inch, the

MTF was measured with a 150 DPI or a 75 line-pair per inch optical bar pattern. The test

were conducted a pixel rate of 2.5MHz.

Figure 4. MTF versus Distance

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}

Recommended Operating Conditions (25° C)

Item

Symbol

Min

Mean

Max

Units

Vdd

4.5

5.0

5.5

V

Vn.

-4.5

-5

-12

V

VLED

5.0

5.5

V

Idd(1&2)

35

55

ma

Ivn (1&2)

6.0

10.0

ma

Power Supply

ILED

460

600

ma

Input voltage at digital high

Vih

Vdd-1.0

Vdd-.5

Vdd

V

Input voltage at digital low

Vil

0

0.8

V

Clock frequency

f

5.5

MHz

Clock pulse high duty cycle

25

%

TYPICAL MTF VERSUS DEPTH OF FOCUS

0

10

20

30

40

50

60

0

0.1

0.2

0.3

0.4

0.5

0.6

DEPTH FROM THE WINDOW SURFACE(mm)

PAGE 7 OF 9 - PI324MC-A4, 11-15-00