Tradition and Innovation
Page 12 / 64
OCTOPUS 300 Service Manual
5
P
RINCIPLE OF
O
PERATION
HAAG-STEIT is the only company offering perimeters with direct projection systems (OCTOPUS 300, 1-2-3). By means of the
‘Optical unit’, which is replacing the cupola, stimuli are directly projected into the patient eye. This technique does not require dark
room condition to take a visual field.
5.1
Functional Diagram
1
3
2
4
5
10
14
9
7
8
6
11
12
13
15
Figure 5-1: OCTOPUS 300
Functional diagram
1
Patient eye
9
Beam splitter 45°
2
Trial lens holder
10 Background illumination
3
Ocular
11 Electronics
4
Image plane
12 Fixation targets
5
Beam splitter 37°
13 Display/Touch module
6
Stimulus projection unit
14 External PC
7
Stimulus LED
15 External printer with USB interface
8
Condenser lens
5.2
Stimulus Intensity Control
The required dynamic range of the stimulus intensity of 40 dB (1:10'000) is achieved with a combined control mode:
a)
Two point current control (I)
b)
Pulse-width modulation (S)
Figure 5-2:
Principle of
stimulus generation
I (LED)
S (MOD)
Stimulus LED
