Microscope assembly having base mount for receiving dimmer circuit components
BACKGROUND OF THE INVENTION 
     The invention generally relates to a microscope with a dimmer which is associated with a light source used for the purpose of illumination in the microscope. 
     Microscopes having a dimmer for adjusting the intensity of illuminating light are already known, and the recent trend is to introduce a dimmer incorporating a thyrister, such as an SCR, a silicon controlled rectifier element, etc., so that the brightness of the light source may be adjusted in a continuous manner. The prior practice to install such electrical components used in the dimmer and/or associated circuit has been to mount these components directly in the interior volume of the base of the microscope in spite of the degree of complexity involved. Thus the individual components are mounted in the interior volume of the base one by one while the base is held in an inverted position. This type of base mounting is cumbersome and a disadvantage in the mass production of microscopes. In addition, where a failure occurs in the dimmer or associated circuit, the whole microscope must be again held in an inverted position in order to permit an examination of the individual components. In view of the foregoing, it is apparent that there is a need in the prior art for a dimmer which overcomes the inconveniences mentioned above. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the invention to provide a base mount for microscopes which comprises a mount separate from the body of an associated microscope and fixedly attached thereto for mounting electrical components thereon which constitute the dimmer, thereby facilitating the assembling in mass production and servicing of the dimmer. 
     In accordance with the invention, only the mount need be handled when assembling or servicing the dimmer. The mount may be removed from the body of the associated microscope and placed on a work table, and the whole assembling or servicing operation of the electrical components can be made on the work table, which greatly facilitates such operation. Since the mount is substantially complete with the required electrical components when it is to be attached to the base of the associated microscope, the attachment becomes a simple operation and the likelihood of damaging the body or base of the microscope is minimized. It is also contemplated that a microscope may require several different voltage ratings for the dimmer depending on local requirements. The use of the mount according to the invention allows an easy replacement of dimmers each including electrical components of different ratings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side elevation of a microscope to which the invention is applied; and 
     FIG. 2 is a similar view of the microscope, with the mount being removed from the body of the microscope to illustrate the assembling operation. 
    
    
     DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT 
     FIGS. 1 and 2 show a microscope to which the invention is applied. The body of the microscope is generally shown at 1, and essentially includes a base 2 and a lens barrel 3 connected together by a limb portion 4, to which a slidable stage 5 is attached. 
     Located within the base 2 is a dimmer 6 (see FIG. 2) which is electrically connected with an internally mounted light source assembly, not shown, through a cable connector 12 and which emits and directs through an internally housed optical system a light beam of an adjusted intensity through a projector lens 7 toward a condenser lens 8 mounted underneath the stage 5. A specimen to be examined (not shown) is placed on the stage 5, and can be observed, upon illumination through the condenser lens 8, through an objective lens 9a on a turret 9 which is mounted on the lens barrel 3 and through an eyepiece 10. During the observation, the stage 5 can be moved vertically for the purpose of focussing by turning an operating knob 11 on a limb portion 4. Magnification can be varied by rotating the turret 9, replacing the objective lens 9a by another objective lens 9b. 
     A tray-shaped mount 20 for mounting electrical components is fixedly attached to the lower portion of the base 2 by means of screws 22a, 22b (FIG. 2), and carries the components such as transformer 14, choke coil 16, thyrister, such as SCR 18, etc., and the like, of a known dimmmer circuit 6. A voltage adjusting knob 13 for manually adjusting the voltage supplied to the light source is mounted on the base 2 and connected to other components of circuit 6 by conventional means, such as the elongated connecting leads 13a and 13b. 
     When the microscope is assembled, the body 1 is assembled separately while the electrical components of a selected known dimmer circuit, including parts 14 to 18, are mounted on the mount 20. After assembly of the body 1, the mount 20 carrying the assembled electrical components is fixedly attached to the base 2 by suitable means such as screws 22a, 22b, for example.