ISD2351 Datasheet, PDF (3/4 Pages) OSRAM GmbH – Sunlight Readability Contrast Measurements

Contrast Measurements
The ability to read a display in direct sunlight used to be deter-
mined by using a series of standard observers and irradiating
the display with one sun. Recent technical studies have estab-
lished contrast criteria permitting laboratory measurements
that verify sunlight readability.
A yellow ISD2351 and a high efficiency green ISD2353 Small
Alphanumeric Display were evaluated for sunlight readability
under a simulated sun with an incident of 4200 fc. These two
displays were tested with both pass-band and neutral density
AR/CP filters. The measurement technique and results follow.
Figure 1. Sunlight readability contrast measurement setup
Contrast Measurement Setup
Contrast measurements require the use of a spot photometer,
which measures the luminance of the surface within a specific
spot size. A Photo Research Spectra Pritchard spot photometer
Model 1980B with a Macro Spectar MS-80 Lens was calibrated
and set to read out in foot Lamberts, fL. The display and filter
were mounted on a micro adjustable X/Y/Z stage. This stage,
the spot photometer, and a 500 W Unimat LX80 light source
were mounted on a optical bench. The light source was ori-
ented 30° from the normal of the display. See Figure 1.
 2000 Infineon Technologies Corp. • Optoelectronics Division • San Jose, CA
www.infineon.com/opto • 1-888-Infineon (1-888-463-4636)
OSRAM Opto Semiconductors GmbH & Co. OHG • Regensburg, Germany
www.osram-os.com • [phone]
3
Appnote 47
May 31, 2000-14