HUL7001 View Datasheet(PDF) - Panasonic Corporation
Part Name
Description
Manufacturer
HUL7001 Datasheet PDF : 6 Pages
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Hologram Unit
HUL7001
Optical Block Diagram During Measurement (Fig. 2)
(a) Radiant power measurement system of
hologram unit (HUL7001)
(b) Reference optical system during measurement
Hologram unit
(HUL7001)
Optical axis
Light detecting element
(ø10mm) or laser light
input element of coherence
measurement system
Apparent light emitting point
25.3mm
Actuator
19.0mm
PKG reference surface
ø3.1mm
aperture
(Note) The aperture and the light detecting element
are positioned perpendicular to the axis of
the light emitted from the hologram unit;
the optical axis is positioned so as to pass
through the center of the aperture.
Collimator lens
f = 25.3mm
NA = 0.105
Objective lens
f = 4.5mm
NA = 0.45
Disk :
A disk satisfying
CD specifications
is used.
The RF signal, focus error signal, and tracking error signal are measured using
the above reference optical system and the equations shown in Fig. 1.
Focus Error Signal Amplitude and Pull-in
Range (Fig. 3)
Tracking Error Signal Amplitude and Pull-in
Range (Fig. 4)
Focus error
signal
IFE
Objective lens
movement
DFE
IFE : Focus error signal amplitude
DFE : Focus error signal pull-in range
Tracking error
signal strength
+
0
Signal amplitude
center ground level
–
B
A
Time
A : Tracking signal amplitude
B : Difference between tracking signal
amplitude center and electrical center
Tracking error signal amplitude ITE = A
Tracking
error
signal
symmetry
BTE
=
B
A
×100
(%)
Focus Error Signal Defocusing (Fig. 5)
High
Jitter
(ns)
Low
+ Focus error signal
DJ : Objective lens movement from position where focus error signal
is 0 to jittering-best position.
S(DJ ) : Amount of focus error signal at DJ
IFE : Focus error signal amplitude
Approaching disk
Moving away from disk
S(DJ)
0
Objective lens
movement (µA)
IFE
DJ
–
Focus error signal
defocusing DFO =
S(DJ)
IEF
×100 (%)
In the diagram, point 0 is the point at
which the focus error signal equals 0.
(Definition of focus error signal defocusing)
Amount of focus error signal at jitter-best position as
a percentage of focus error signal amplitude (%)
3
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