Front Optics

Front Optics for Hazard Measurements with specbos 1211UV

The hazardous effect of light radiation to the human eye and skin was studied for a long time and several standards and by-laws regulate the handling. Today more and more attention is payed to the effect of incoherent optical radiation on the human body. Typical examples for such light sources are flood lights and other LED based illuminaires.scb1211uv

There are 8 categories of hazardeous effects on human eye and skin defined in the documents EN 62471 and ANSI/ IESNA RP-27. specbos 1211UV can be used to measure the optical quantities related to these categories if its restriction to the wavelength range 230 to 1000 nm and its other optical parameters are considered.

There are several special accessories are available for this task.

The Radiance based measurements can be done with viewing angles of 100 mrad and 11 mrad. The Irradiance based measurements will be done using a special diffusor with a measuring diameter of 8 mm. Due to the very high intensities of hazard measurements the signal must be attenuated by neutral density filters placed inside of the accessories. Additionally external filters can be used.

The theoretical background and the measuring procedures are described in application note 26.

group acc

The following table shows the available accessories for specbos 1211UV:

Accessory Application Part number
100 mrad beam shaping optics with internal attenuation filter UVOD2.0 and external UVOD1.0 + UVOD2.0 Blue Light hazard, > 10 000 s ACC 024/100
11 mrad beam shaping optics with internal attenuation filter UVOD2.0 and external UVOD1.0 + UVOD2.0 Blue light hazard, 10 … 100 s
Retina thermal, 10 s
ACC 024/11
Mechanical elements for turning/ tilting Finding the maximum signal of Radiance based measurements ACC 025
Diffusor for Irradiance measurement (Actinic UV and UVA hazard), spot size Ø8 mm Blue Light (small source)
Actinic UV*1
Eye UV-A
ACC 026
Additional filter cap for ACC 024; OD or bandpass type Reducing the straylight for UV measurements ACC 029UVODX.X
80° aperture for Diffusor Actinic UV and Eye UV-A, if the extension of the source is > 80° ACC 027
*1  specbos 1211UV measure in wavelength range 230 ... 1000.
100 mrad od1
specbos 1211UV with Beam shaping optics for 100 mrad Radiance measurement with UVOD1.0 filter (ACC 024/100OD1.0) and mechanical elements for turning / tilting (ACC 025)


Hazard measurements must be made with a double monochromator based system. A spectroradiometer with an array spectrometer as specbos 1211UV can be used only if its applicability is proved! Due to the specifics of hazard measurements it is recommended to discuss the application with JETI to find the best solution.