Delta LTL2000S - Manual (Page 15)

DELTA LTL2000S(Q) Retroreflectometer 11
SECTION 2
GENERAL INFORMATION
Rl Measurement
The Rl part of the LTL2000S(Q) Retroreflectometer measures the Rl (coefficient of retro re-
flected luminance) parameter. The Rl parameter represents the brightness of the road mark-
ings seen by drivers of motor vehicles by headlight illumination.
The illumination angle is 1.24
° and the observation angle is 2.29° simulating a drivers view-
ing distance of 30 metres at an eye height of 1.2 metres. The observation area is app. 45 mm.
x 200 mm.
The optical specification complies with EN1436. The spectral sensitivity is eye matched us-
ing SMART optical filter designed and produced by DELTA. The functional layout of the
LTL2000S(Q) Rl optical system is shown in figure 3 below.
A very efficient electronic stray light compensation eliminates false signals from daylight.
101 102
103 104
107
108 109
105 106
112 111
110
Figure 3: LTL2000S(Q) RL optical system layout
101 Light source
102 Receiver and spectral matching
filter
103 Illumination aperture stop
104 Observation aperture stop
105 Illumination beam
106 Observation beam
107 Collimating lens
108 Mirror
109 Beam splitter
110 Road marking surface
111 Illumination field
112 Observation field