Abstract:
A removable objective lens arrangement ( 5 ) having a removable plate ( 30 ), at least one support device ( 60,70 ) fixably mounted on the removable plate ( 30 ) and an objective lens ( 40 ) adjustably mounted within the at least one support device ( 60, 70 ).

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims benefit to and priority of UK Patent Application No. 1320728.7 filed on 25 Nov. 2013. 
       FIELD OF THE INVENTION 
       [0002]    The field of the invention relates to a removable objective lens arrangement for mounting at least one objective lens. 
       BACKGROUND OF THE INVENTION 
       [0003]    A microscope is a scientific instrument that is used to image objects, which either are too small themselves or have details that are too small to be visible to the naked eye. There are many types of microscopes available on the market. The most common of these and the first to be invented is the so-called optical microscope, which uses light in a system of lenses to magnify images of the samples. The image from the optical microscope can be either viewed through an eyepiece or, more commonly nowadays, captured by a light-sensitive camera to generate a so-called micrograph. The images were previously captured on photographic film, but modern developments in charge-coupled device (CCD) cameras allow the capture of digital capture and storage of digital images. 
         [0004]    The illumination sources used in optical microscopes have been developed over the years and wide varieties of illumination sources are currently available, which can emit light or other types of radiation at different wavelengths. Optical filters can be placed between the illumination source and the sample to be imaged in order to restrict the wavelength of the radiation illuminating the sample. 
         [0005]    Modern biological microscopy uses fluorescent probes for imaging specific structures within a cell as the sample. In contrast to normal trans-illuminated light microscopy, the sample in fluorescence microscopy is illuminated through an objective lens with a narrow set of light wavelengths. These narrow set of light wavelengths interact with fluorophores in the sample, which then emit light of a different wavelength. This emitted/fluoresced light is used to construct the image of the sample. 
         [0006]    Some modern microscopy methods, for example selective plain illumination microscopes (SPIN), multi-view SPIN and 4 Pi microscopes utilize multiple objective lenses that are focussed on the same experimental volume containing the sample to be imaged. In these microscopy methods, the correct relative position of the multiple objective lenses is important for a proper functioning of the microscope. Experience has shown that the positioning of the multiple objective lenses requires time for adjustment, for example 3 to 4 hours for any new samples. This adjustment has to be repeated if one or more of the multiple objective lenses is removed from the microscope. 
         [0007]    For example, suppose that a user wishes to use an objective lens with a different magnification. Each time the objective lenses with different magnifications (or other properties) are exchanged, an adjustment of the relative position has to take place. This adjustment leads to downtime of the microscope. 
         [0008]    U.S. Pat. No. 5,668,660 (Hunt) teaches a microscope having an objective lens and a pair of zoom lenses arranged in series along an optical path from the objective lens to a video camera. The objective lens is fixed on a holder, which can be removably mounted in a receptacle on the microscope housing, and is retained therein by a manually releasable latch. The holder includes a number of set screws that co-operate with a spring to permit adjustment of the objective lens and to centre the objective lens after the objective lens has been mounted in the receptacle. The objective lens can be removed from the microscope by depressing a release button and pivoting a latch leaver to its release position, thereby accommodating quick and easy removal of the holder form the receptacle. 
         [0009]    The teachings of the Hunt disclosure relate only to a single objective lens within an insert on the microscope. There is no provision for two objective lenses to be mounted at an angle to each other. The set screws and the spring are mounted directly on the microscope in the Hunt disclosure. 
         [0010]    German patent application No. DE 10 2006 024 109 (Wahl et. al, assigned to Carl Zeiss Microimaging GmbH, Jena) teaches a microscope with a so-called exchange device. The exchange device has a plurality of optical elements with differing optical properties and which can be quickly exchanged with each other. The microscope has means, which enable the mounting of a single optical element and/or a magazine with optical elements having deferring properties. The arrangement of this disclosure includes a linear slide with a plurality of mounts for accepting optical elements such as filters or reflectors. The optical elements cannot be individual adjusted with the magazine or the linear slide. 
       SUMMARY OF THE INVENTION 
       [0011]    A removable object lens arrangement comprising a removable plate with at least one support device fixedly mounted to the removable plate is disclosed. An objective lens is adjustably mounted within the at least one support device to enable imaging or/and illumination of a sample. The objective lens is held in position by a front support and a back support of the support device. This lens arrangement allows the placement of the objective lens in a fixed position within a microscope and enables the objective lens to be easily removed from a base plate of the microscope and then reinserted without time-consuming adjustment of the position of the objective lens. 
         [0012]    The lens arrangement comprises in one aspect two objective lenses. One of the objective lenses is used to illuminate a sample (an illumination lens) within the microscope and the other one of the objective lenses is used to image the illuminated sample (an imaging lens). The position of each one of the objective lenses can be adjusted in three dimensions, which leads in total to five degrees of freedom. The removable plate holds the objective lenses firmly in position and maintains the relative orientation of the objective lenses to each other to avoid later refocusing and reimaging of the sample. 
         [0013]    The front support comprises at least one adjustable screw, formed in one aspect with a bearing and a co-operating spring to move the front end of the objective lens in a front plane. The back end of the support holds the objective lens firmly in position, but allows a movement of the objective lens in the front plane. 
         [0014]    A translation device can be used for translating the position of the objective lens in a direction substantially parallel to the plane of the removable plate. 
         [0015]    The removable plate comprises fixation devices, which cooperate with a fixed place plate on the microscope, to hold the removable plate in position and to adjust the position of the removable plat on insertion into the microscope. 
     
    
     
       DESCRIPTION OF THE FIGURES 
         [0016]      FIG. 1  shows two objective lenses mounted on a removable plate. 
           [0017]      FIGS. 2 a - c    shows one of the objective lenses mounted on the removable plate. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0018]    The invention will now be described on the basis of the drawings. It will be understood that the embodiments and aspects of the invention described herein are only examples and do not limit the protective scope of the claims in any way. The invention is defined by the claims and their equivalents. It will be understood that features of one aspect or embodiment of the invention can be combined with a feature of a different aspect or aspects and/or embodiments of the invention. 
         [0019]      FIG. 1  shows a removable objective lens arrangement  5  with two objective lenses  40  mounted on a removable plate  30  with the help of a support device. The support device comprises a front support  60  for supporting a front end  42  of the objective lens  40 . The support device further comprises a hack support  70  for holding the rear end  44  of the objective lens  40 . 
         [0020]    The removable plate  30  can be mounted on a fixed base plate  10 , which is part of a microscope. The fixed base plate  10  has, in this example, one or more pins  20 , which cooperate with recesses (not shown) on the underside  31  in the removable plate  30  to fix the removable plate  30  on the base plate  10 . It will be appreciated that other forms of fixation devices can be used in order to fixedly hold the removable plate  30  on the base plate  10 . 
         [0021]    The front support  60  has a front opening  62  through which the front end  42  of the objective lens  40  is inserted. The front end  42  of the objective lens  40  is held in position in the front support  60  by means of adjustable screws  50 .  FIG. 1  shows three adjustable screws  50  mounted at approximately  120  degrees to each other, but this is not limiting the invention. It will be appreciated that fewer or more adjustable screws  50  can be used. The adjustable screws  50  are used to move the objective lens  40  in two dimensions in a plane of the front support  62  located perpendicularly to the axis of the objective lens  40 , shown as directions y and z for the left hand objective lens  40  in  FIG. 1 . It will be noted that one or more of the adjustable screws  50  can be replaced by a spring and bearing or similar to support the objective lens  40 . 
         [0022]    It will be appreciated that an operator can therefore adjust both of the two objective lenses  40  shown in  FIG. 1  such that a sample (not shown) is illuminated by one of the objective lenses  40  and imaged by another one of the objective lenses  40 . The two objective lenses  40  are mounted so that their optical axes are at substantially right angles to each other. 
         [0023]    The back support  70  is formed of a so-called flexure which comprises, in this aspect, three aluminium bands  71  which can be tightened about the objective lens  40 , but allow movement in the plane of the front support  62 . 
         [0024]      FIG. 2  shows the objective lens  40  in three views.  FIG. 2 a    is a cross-sectional view.  FIG. 2 b    is a front view from the front end  42  of the objective lens  40  and  FIG. 2 c    is a side view of the objective lens  40 . The same reference numerals are used in  FIGS. 2 a - c    as in  FIG. 1  and represent the same elements. 
         [0025]      FIG. 2 a    shows additionally a translation screw  80 , which is used to adjust the longitudinal direction (x-direction) of the objective lens  40  within the support device. It will be seen, from  FIG. 2 b   , that the adjustable screw  80  is inserted into a corresponding hole  82  in the removable plate  30 . 
         [0026]    The adjustable screws  50  have a bearing  52  cooperating with a spring  54  to hold the front end  52  of the objective lens  40  within the front support  60 . 
         [0027]    It will be seen from  FIG. 2  that the removable plate  30  has a dove tail  32  which cooperate with corresponding fixations on the base plate  10  to hold the removable plate  30  into position.