Maximum Immersion Depth For Lenses - THORLABS DCU223x Operation Manual And Sdk

DCx Cameras
Hint
You can use the following formula to calculate the mechanical flange back distance:
The tolerances for the position accuracy of DCx camera sensors are given in the
Calculating the flange back distance for DCx Cameras with C-mount
Thickness sensor
Camera model
Designation
CMOS
DCC1240x /
DCC3240x
461
CCD
DCU223x
468
DCU224x
470
Calculation example: UI-154x-xx with IR-cut filter
(a = 17.526 mm, d = 0.525 mm, nGlass = 1.50, f = 1mm, nFilter = 1.53; see
Calculating the flange back distance for DCC1545M and DCC1645C cameras with CS-mount
Note
For these cameras with CS-mount, the flange back distance is only 12.526 mm.
Thickness
Camera model sensor
glass [mm]
Designation
DCC1545M 0.525
464
DCC1645C 0.550
466

5.4.5.2 Maximum Immersion Depth for Lenses

Some C-mount lenses reach deep into the camera flange. This may cause the lens to push against the back of the
filter glass inside the camera or even make it impossible to screw in the lens.
The table below indicates the maximum possible immersion depth for each DCx camera model. The actual
immersion depth of a lens is given in the relevant data sheet. As lens parts with a small diameter are allowed to
reach deeper into the camera flange, the immersion depths are specified based on the diameter.
Beside the immersion depth also the back focal length has to be considered, that means the distance between the
last lens and the sensor (named "bfl" in the image below). The back focal length can be calculated for C-mount with
the following formula:
x stands for the maximum immersion depth (see table below).
478
Active sensor
area to PCB
glass [mm]
[mm]
d
0.550 1.130
0.750 2.810
0.750 2.810
Active sensor
area to PCB
[mm]
d e
1.270
1.400
Flange to active
sensor area
without filter glass
[mm]
e x'
18.840
20.590
20.590
Threaded Flange to active
flange to sensor area
active without filter
sensor area glass[mm]
a x
13.23 15.95
13.10 16.08
bfl 17 , 526 x
Position accuracy
Sensor height
Flange to active
above the PCB
sensor area with
filter glass [mm]
x
19.190
20.930
20.930
Filter types table)
480
Flange to active Sensor height
sensor area with above the PCB
filter glass [mm]
x'
17.50
17.63
© 2013 Thorlabs GmbH
chapter.
480
[mm]
h
2.530
4.780
4.830
[mm]
h
2.480
2.500