OSRAM PrevaLED Core Z2 - Manual (Page 8)

8
2. Optical considerations
OPTICAL CONSIDERATIONS
Chip-on-board-design (CoB)
So-called chip-on-board (CoB) light sources without
housing and with high-performance chips set very closely
next to each other have proven to be especially advanta-
geous. Due to the large amount of applied chips, the size
of the light source is fl exible and scalable. In the applica-
tion, the compactness, on the one hand, allows for very
high axis light and illumination levels, and, on the other
hand, a very high-contrast illumination with high brilliance.
Very good homogeneity (with a uniformity factor of 0.93) –
combined with constantly Lambertian radiation – addition-
ally simplifi es refl ector design and facilitates the inter-
changeability of light sources.
The CoB design is characterized by a large amount of
closely set LED chips, arranged in a certain grid which is
covered with luminescent material (cf. the image above).
One of the key advantages of this design is its very homo-
geneous light-emitting surface.
Pure phosphor conversion with CoB
Thanks to the use of pure phosphor conversion, the
PrevaLED
® Core Z2 module can achieve a color rendering
quality of higher than CRI 90, while at the same time
providing a very homogeneous light output.
Phosphor conversion: By means of phosphor conversion, the blue
light of the LED chip is shifted towards the higher wavelengths of
green and red light.
PrevaLED ® Core Z2
2.1. Refl ector
High luminous densities (1.5–4.5 Mcd/m
2 ) are the key
factor for LED-based lamps and luminaires in the area of
refl ector applications such as spotlights, for example.
For these, light sources with small light-emitting areas
and a high luminous fl ux are required (as realized with the
PrevaLED
® Core Z2), because that way, the light can be
collimated especially well with refl ectors.
Thanks to CoB technology, the PrevaLED ® Core Z2 has
a uniform light-emitting surface which, due to its great
homogeneity, eliminates the need to use diffuser material.
The minimized light-emitting surface (LES) and a refl ector
positioning close to the LES allows for better optical
handling. All in all, the properties of the PrevaLED
® Core Z2
allow for the prevention of roughness and facets, which in
turn allows for minimal overall beam angles of 10° or less.
The high homogeneity of the PrevaLED ® Core Z2 means:
• Low complexity in the surface structure of the refl ector
• Narrower beam angles <10° FWHM in combination with
minimized light-emitting surface
PrevaLED ® Core Z2