TELEVISION MICROSCOPE 



Fig. 1. Diagram of the path of rays in the Zeiss-Siemens television microscope. Left with trans- 

 mitted, right with incident light. 



number of viewing screens, practically every- 

 thing visible in the microscope can be shown 

 simultaneously to an audience of any size. 

 Naturally that holds not only for micro- 

 scopic imaging in bright field with trans- 

 mitted light, but also for the various miag- 

 ing procedures with unfavorable light yield, 

 as for example dark-field, phase contrast, or 

 epimicroscopy. 



This optical system projects the micro- 

 scopic image at suitable magnification on 

 the receptive surface of the television camera 

 tube and provides for a continuous mag- 

 nification regulation in the ratio of 1:3.2 

 without change of optics as shown in Fig. 1. 

 For incident illumination an auxiliary lens 

 is inserted in the front opening of the lamp 

 carrier in place of the quadruple filter holder. 

 Unexceptionable maintenance of the Koeh- 

 ler illumination principle is assured in each 

 case. The imaging beam is deflected at a 

 right angle from the projective to the tele- 

 vision camera by a prism located in an 

 adapter which is screwed into the threaded 

 objective ring of the television camera. A 

 light-excluding tube provides for lightproof 

 connection between adapter and projective. 



Operation of the Ziess-Siemens microscope 

 takes place in customary manner. A small 

 remote control desk is located on the table 

 for regulating the television installation. 



Cables pass from it as well as from the cam- 

 era to the central power supply of the tele- 

 vision installation. The control monitor with 

 its 17-cm picture tube, set up on the table, 

 is likewise connected with the central power 

 supply. Additional viewing apparatus of 

 optional screen size, number, and distance, 

 and also a television projection receiver are 

 connected by means of a coaxial cable op- 

 tionally to the central power supply or to a 

 control receiver. Up to three television cam- 

 eras can be directly connected to this central 

 power supply. They can be applied m a most 

 diversified manner. Since the Siemens tele- 

 vision installation is equipped with a so- 

 called automatic gain control, its operation 

 is restricted to switching on and off, and the 

 occasional refocusing of the camera tube and 

 regulating the image brightness of the re- 

 ceivers according to the brightness of the 

 room. This means that during actual use its 

 operation is essentially restricted to manip- 

 ulation of the microscope and consequently 

 is simpler than that of a microprojection 

 apparatus. Basic considerations and the 

 experience gained thus far indicate unequiv- 

 ocally the advantages of the television 

 principle of microscopy. Adapted from an 

 article by Helmut Haselmann in Zeiss 

 Werkzeitschrift, No. 29, p. 42 (Sept., 1958). 



G. L, Clark 



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