The PMA1131 Scotopic Light Sensor is a portable analog light sensor (Lux sensor) with spectral response following the CIE scotopic action spectrum. This sensor is designed to have a spectral response like that of the human eye’s visual response in the photopic region.

> Return to Sensor Selection Guide

PMA1131 Scotopic Light Sensor

U.S.Pat.5,946,641

U.S.Pat.5,790,432

FEATURES

• High sensitivity
• Wide dynamic range
• Excellent long term stability
• Cosine corrected
• NIST traceable calibration
• Selectable units
  

APPLICATIONS

• Low light level testing
• Night vision technology
• Display and illuminator testing
• Luminescence and fluorescence
• Photography and film studios
• Clinical studies

> Weatherproof UVA Detector available

> Underwater UVA Detector available

> Wiring Diagram

The spectral response of the human eye changes with light intensity. The eye has two distinctive spectral responses, which are defined according to the brightness of the light entering the eye. The first spectral response of the eye occurs under typical daytime lighting conditions (photopic) defined for light intensity greater than 0.1 Lux. The second spectral response occurs under low light conditions (scotopic) defined for light intensity between 0.01 and 0.0001 Lux. Light intensity less than 0.0001 Lux is undetectable by the human eye. The eye's shift from the photopic response to the scotopic response is know as the Purkinje shift. The scotopic spectral luminous efficiency curve peaks at 507 nm and it is normalized to 1
at that wavelength.

The power-like unit of brightness-sensation-producing ability of light is lumen [lm]. The relationship between effective Watts and scotopic lumen is now assumed to be 1754 lm/W. For example, 507-nm monochromatic radiation flux of 0.0001W would carry the scotopic luminous flux of 0.1754 lm. Please note, that photopic spectral luminous efficiency as well as the conversion factor between Watts and photopic lumens differ from their scotopic counterparts.

Scotopic Light Sensor Specifications

• Spectral response Follows CIE scotopic spectral luminous efficiency curve (400-600nm) Figure 1
• Angular response 5% for angles <60°
• Range:

      PMA1131 - 200,000 scotopic mLux, 20,000 mft-cd, 120,000 μW/m²

      PMA1131D - 500 Lux, 48 ft-cd

• Display resolution

      PMA1131 - 0.001 Lux 0.01 ft-cd 1 µW/m²

        PMA1131D - 0.001 Lux, 0.001 ft-cd

• Operating environment 32 to 120 °F (0 to +50 °C) no precipitation
• Cable  5ft (1.5m)
• Diameter 1.6" (40.6 mm)
• Height 1.8" (45.8 mm)
• Weight 7.1 oz. (200 grams)
  

> Return to Sensor Selection Guide