 2000 Infineon Technologies Corp. • Optoelectronics Division • San Jose, CA

Appnote 47

www.infineon.com/opto • 1-888-Infineon (1-888-463-4636)

OSRAM Opto Semiconductors GmbH & Co. OHG • Regensburg, Germany

www.osram-os.com • +49-941-202-7178

4

May 31, 2000-14

Figure 2. LEDs selected for measurement

The sterance measurements were made using the photometer

with an angle setting of 2 minutes resulting in a spot size of

.004 in. The incidence flux was determined by using a Kodak

6080 standard lambertian reflector painted slide.

The X/Y/Z stage supported the display, the AR/CP filter, and the

display drive electronics. Figure 3 shows the asterisk (*) pro-

grammed on the display. Each LED had a duty factor of ON

17.6%. The center of the asterisk was used as the measure-

ment LED. The stage was used to position the display at the

four contrast measurement points as shown in Figure 2.

Contrast Calculations

The data derived from the spot photometer was used to calcu-

was the average of three spot locations. Figure 3 shows these

See Figure 3

for exploded view

Figure 3. Points for luminous stearance measurement

Measurements were made using a yellow ISD2351 and a

Marks MPC80-10C neutral density gray filter. This display had a

typical intensity of 2450 µcd/LED with an average wavelength

of 585 nm.

Measurements were also made using a green ISD2353 with a

Marks MPC50-22C yellow/green bandpass filter and a Marks

MPC80-10C neutral density gray filter. This display had a typi-

cal intensity of 3470 µcd/LED with an average wavelength of

572 nm.

The data and results of the experiment are shown in Table 2.

Conclusion

From the data, the most readable combination is the green

ISD2353 display and a green bandpass AR/CP filter, followed by

the green display and the 10% transmissive neutral density

gray AR/CP filter. In both cases these combinations exceeded

the military limit by almost 2.5 times. The yellow display has

optimum contrast with a neutral density AR/CP gray filter.

Lc

Ld

La

Lb

Table 2. Luminous contrast at 4200 fc

Display Color

Filter Model #

Status

Footlamberts

Green

MPC50-22C

LED-On

LED-Off

12.00

11.00

10.20

9.40

27.10

20.60

101.60

12.60

16.43

13.67

5.18

7.06

0.08

Green

MPC80-10C

LED-On

LED-Off

9.70

8.80

8.60

8.60

17.80

11.40

69.80

10.10

12.03

9.60

4.80

5.91

0.05

Green

MPC50-22C

LED-On

LED-Off

12.60

11.10

11.30

9.80

37.30

17.70

111.00

14.40

15.30

12.87

6.25

6.71

0.12

Yellow

MPC80-10C

LED-On

LED-Off

9.30

7.80

8.20

7.20

19.40

10.30

46.50

7.70

12.30

8.43

2.78

5.04

0.09

Yellow

No Filter

LED-On

LED-Off

208.00

198.00

198.00

171.00

650.00

853.00

480.00

171.00

352.00

407.33

0.36

1.81

0.58