Table of Contents
Advertisement
5. Lenses & lens holder
5.7
Scheimpflug adjustment
What has to be done ?
The lens holder has to be adjusted so that the "sharp focus plane" of the projected image falls together with the plane of the screen
(Fp1→Fp2). This is achieved by changing the distance between the DMD plane and the lens plane (Lp1→Lp2). The closer the lens
plane comes to the DMD plane the further the sharp focus plane will be. It can sometimes happen that you won't be able to get a
complete focused image on the screen due to a tilt (or swing) of the lens plane with respect to the DMD plane. This is also known
as Sheimpflug's law. To solve this the lens plane must be placed parallel with the DMD plane. This can be achieved by turning the
lens holder to remove the tilt (or swing) between lens plane and DMD plane (Lp3→Lp4).
Lp1
Lp2
DMD
Image 5-35
Scheimpflug principle
Scheimpflug principle
The "plane of sharp focus" can be changed so that any plane can be brought into sharp focus. When the DMD plane
and lens plane are parallel, the plane of sharp focus will also be parallel to these two planes. If, however, the lens
plane is tilted with respect to the DMD plane, the plane of sharp focus will also be tilted according to geometrical and
optical properties. The DMD plane, the principal lens plane and the sharp focus plane will intersect in a line below the
projector for downward lens tilt.
Scheimpflug adjustment points
1
4
Image 5-36
Scheimpflug adjustments
Indication on drawing
4
1, 2 and 3
A, B, C and D
a, b, c and d
1, 2 and 3 are adjustment points.
4 is a locking point and NOT used during Scheimpflug adjustment.
82
A
a
B
b
2
3
c
d
C
D
Function
Locking nut
Scheimpflug adjustment nuts
Set screws
lock nuts
Fp1
Fp2
DMD
Lp3
Lp4
R5905963 PROMETHEUS SERIES 09/03/2015
Fp4
Fp3
(Scheimpflug)
Advertisement
Table of Contents
