Optical viewing system and method for operating the same

A method for operating a surgical microscope defining a beam path and including a reflecting-in display unit having a plurality of controllable display pixels to generate a display image;

• a superposition unit for superposing said display image onto an image of said region of said object to form a superposed image in said beam path;
• a camera unit for receiving said superposed image;
• and, said camera unit including an image sensor;
• the method comprising the steps of:
• causing a display pixel of said plurality of controllable display pixels to sequentially emit color pulses in a color pulse sequence train;
• and,
• utilizing said image sensor to detect at least two color pulses of different color from said color pulse sequence train
• wherein color pulses of different pulse duration (t7, t6, . . . , t0) are sent out in light pulse sequences which follow one upon the other and the image sensor detects at least one light pulse sequence with three different colors (R, G, B), and
• wherein the ratio of a rate, with which color pulses are sent out at a rate with which the image sensor scans different colors, is a rational number.

An optical viewing system for viewing a region of an object along a beam path, the optical viewing system defining an optical axis for said beam path and comprising:

• a tube for viewing said region along said optical axis;
• a main objective arranged on said optical axis;
• a reflecting-in display unit having a plurality of controllable display pixels which provide light in different colors in order to generate a display image which is built up from a plurality of image points and is reflected toward said beam path;
• a beam splitter disposed on said optical axis between said tube and said objective;
• said beam splitter being mounted to receive said display image and to superpose said display image onto an image of said region of said object to form a superposed image in said beam path viewable by an operator through said viewing tube;
• a camera unit for receiving said superposed image;
• said camera unit including an image sensor having a light sensitivity;
• each one of said display pixels being adapted to generate a pulse sequence train from a plurality of light pulse sequences having light pulses of different colors;
• and,
• said light sensitivity of said image sensor being matched to said pulse sequence train so as to permit said image sensor to detect at least two light pulses of different colors (R, G, B) from said pulse sequence train.