Leica OH4, Service Manual, Page: 23 / 264

Service manual Leica OH4 Technical description
Doc. Code 10 665 744 1-9 09/2006 3243 – GOR
Correcting the balancing manually
For manual balancing, the axes can be moved manually using switches A, B, and C
Correcting the D-balancing manually
The D-balancing of the stand can be corrected with the “+” and “-“ keys on the “Main” screen of the control unit.
Balancing mechanism
It consists of a lever, located between two mechanical limits. Two electrical switches
indicate the position of the lever. The lever is mechanicaly connected to the appropriate
axes and takes over the torque.
In all there are 3 balancing mechanism, one for the axis A and B, one for axis C and one for
axis D.
Illumination
Press push-button for illumination. The illumination comes on and the push-button is lit green.
Adjusting the brightness
Brightness can be increased or decreased using the touch panel monitor or a handswitch/footswitch or CAN handle.
On the touch panel monitor:
Press the “+” or “-“ key on the brightness adjustment bar for illumination or adjust the brightness directly in the bar.
BrightCare™
BrightCare™ is a safety function which automatically limits the maximum brightness depending on the working distance.
Excessively bright light can, in combination with a short working distance, cause burns in patients.
Explanation of luminous energy:
The optics of the Leica M525 OH4 surgical microscope have a variable working distance between 207 and 470mm. The system is
designed in such a way that it delivers sufficient light to produce a bright image even at a long working distance of 470mm.
According to the formula E
v =
l
v/
d², luminous energy increases constantly to 510% as a function of a reduction in working distance
from 470 to 207mm. (Ev = light intensity, Iv = brightness, d = distance from light source).
This means that less light is required to work with the microscope at a shorter distance than at a greater distance.
It is advisable to begin with low light output and increase the light intensity until an optimum level of illumination is achieved.
Explanation of heat release:
Heat from non-visible light (over 700nm) is filtered out of the light from the used xenon light source. Nevertheless, white light
always releases heat. An excessive amount of white light can cause overheating of tissue and metallic objects.
This safety function can be deactivated by clicking the “Brightcare™” button. When the “Brightcare™” safety function is
deactivated, the color of “Brightcare™” button changes from green to yellow.