Patent Publication Number: US-2011058030-A1

Title: Digital microscope

Description:
CROSS REFERENCE TO RELATED APPLICATION(S) 
     This application claims priority to and the benefit of EP Application No. 09169160.0, filed Sep. 1, 2009, the content of which is hereby incorporated by reference in its entirety. 
     FIELD OF THE INVENTION 
     The present invention relates to a digital microscope having a reflective member located at a distal end. 
     BACKGROUND OF THE INVENTION 
     Digital microscopes provide a convenient means for viewing magnified images. Digital microscopes use optics and sensors to record or output a magnified image to a monitor. Digital microscopes can be attached to a standard camera having a built-in screen, or they can be connected directly to a computer using a Universal Serial Bus (USB) connection. When a microscope is attached to a computer, an image can be shown on an associated screen without additional hardware. 
     Digital microscopes with USB connections that are currently on the market are typically hand-held and can be held like a pen for top-down surface viewing. The size and portable nature of these digital microscopes makes them a useful tool for viewing small areas of large objects where, for example, it is not possible or desirable to place a sample of the object on the stage of a more traditional microscope. 
     Existing digital microscopes typically have a movable lens positioned parallel to an opening of a body in which the lens is held. To obtain a clear image, it is preferable for the end of the microscope to be pressed against an object being viewed. As a result, these microscopes are only useful for viewing images in two-dimensions, as if from directly above the surface of an object. There is therefore a need to provide an improved digital microscope through which alternative views of the same object can be seen. 
     SUMMARY OF THE INVENTION 
     The present invention relates to a digital microscope for viewing the surface of an object, the microscope comprising a) housing having a proximal end and a distal end, said housing having an opening at the distal end, b) a sensor that receives light reflected from the surface of an object being viewed and converting said light to a digital image, the sensor being located at a proximal end of the housing, c) a lens that focuses light reflected from the object onto the sensor, the lens being located between the sensor and the opening, and d) a reflective member located within the opening, wherein, in use, light is reflected from the object to the sensor and a portion of said reflected light is directed via the reflective member such that the surface of the object can be viewed simultaneously from two different directions. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the invention will hereinafter be described, by way of example, with reference to the accompanying drawings, in which: 
         FIG. 1  is a perspective view of one possible embodiment of a digital microscope. 
         FIG. 2  is a schematic view of the embodiment shown in  FIG. 1 , showing different paths of light. 
         FIG. 3  is a schematic view of an alternative embodiment of a digital microscope. 
         FIG. 4  is a perspective view of an alternative embodiment of a digital microscope. 
         FIG. 5  is an exploded view of the digital microscope shown in  FIG. 4 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The invention is applicable to digital microscopes, particularly to hand-held digital microscopes. 
       FIG. 1  shows a perspective view of a digital microscope  10  formed of a housing  12  having a proximal end  14  and a distal end  16 . The distal end  16  forms an opening  18  to the housing  12 . In use, the opening  18  is pressed against or placed near objects intended for viewing. A lens  20  is located within the housing, perpendicular to a length, l, of the housing  12 . The lens  20  is movable between the proximal  14  and distal  16  ends of the housing  12  to allow a user to focus on an object to be viewed. A sensor  22  is provided between the lens  20  and the proximal end  14  of the housing. In use, light is reflected from the surface of an object to the lens  20  and subsequently focused on the sensor  22 . The sensor  22  is preferably a charge-coupled device (CCD) that captures the reflected light and converts it to digital data that is recorded for the microscope, in the manner of a camera. A resulting image is shown on an associated screen  24 . This screen  24  may be directly attached to the microscope  10  (not shown) or the microscope  10  may have a Universal Serial Bus (USB) connection  26  such that the image may be viewed on a computer screen  24 . 
     A reflective member  40  is secured to a projection  42  that is located within the opening  18  of the housing. The projection  42  shown in  FIG. 1  has a first side  44  in line with an edge  46  of the opening  18 , a second side  48  adhered to an internal surface  50  of the housing  12 , and a third side  52  to which the reflective member  40  is adhered. The projection shown in  FIG. 1  is rectangular in shape. However, it will be appreciated that any form of projection  42  or securing member can be used to secure the reflective member  40  in the desired position. For example, the projection  42  shown in  FIG. 2  is triangular in shape. Furthermore, it will be appreciated that the projection  42  may be formed integrally with the housing or secured to an internal surface of the housing in a known manner. 
     In the embodiment shown in  FIG. 1 , the reflective member  40  is a mirror  60 . The mirror  60  is fixed to the third side  50  of the projection. A reflective surface  64  of the mirror has a first edge  66  located adjacent the internal surface  50  of the housing and a second edge  62  substantially in line with the edge  46  of the opening  18 . It will be appreciated that the mirror  60  could extend beyond the edges of the projection  42 . The reflective surface  64  of the mirror  60  is positioned at an angle, α, of between 30°, 35° or 40° and 50°, 55° or 60° to the internal surface  50  of the housing  12 . In a particular embodiment, the mirror  60  is positioned at an angle α of 45° to the internal surface  50  of the housing  12 . The second edge  62  of the mirror  60  is positioned away from the internal surface  50  of the housing to which the projection is attached at a distance of between 30%, 35%, 40% or 45% and 55%, 60%, 65% or 70% of the diameter, d, of the opening end of the housing. In a particular embodiment, the second edge  62  of the mirror  60  is positioned a distance of 50% of the diameter, d, of the opening of the housing away from the internal surface  50  of the housing  12  to which the projection  42  is attached. 
       FIG. 2  shows the different paths of light between an object  100  being viewed and the sensor  22  in a digital microscope  10  as described above. When following a first path of light, path A, light is reflected directly from the object  100  to the lens  20  for focusing on the sensor  22 . By contrast, a portion of light that follows a second path of light, path B, is reflected from the object  100  to the reflective surface  64  and subsequently to the lens  20  for focusing on the sensor  22 . Light that follows path A is shown on one side of the resulting image and gives a view as if from directly above the object  100 , while light that follows path B is shown on the other side of the resulting image giving a view of the object  100  as if from the side. The second edge  62  of the mirror  60  forms a split-line dividing the resulting image in two. 
     Changing the angle at which the mirror  60  is oriented relative to an internal surface  50  of the housing  12  alters light path B. If an object is expected to protrude through the opening  18  of the housing  12  by a substantial distance, it may be preferable to position the mirror  60  at an angle of 60° or above. By contrast, if the object does not protrude through the opening  18  at all, it may be desirable to decrease the angle to extend the field of view of the image reflected in the mirror  60 . However, if the angle becomes too small, the views in the first part of the image and the second part of the image will be approximately the same. 
     Changing the distance, D, of the second edge  62  of the mirror  60  from the internal surface  50  of the housing  12  determines how the resulting image is split between the two views. As the second edge  62  of the mirror  60  extends further into the opening  18  of the housing  12 , the ratio of the size of image A to image B decreases. 
     The mirror  60  shown in  FIGS. 1 and 2  is a first surface mirror. First surface mirrors have the reflecting surface placed on the front or first surface of the glass to eliminate internal reflection. In the present application, use of a first surface mirror prevents ghosting of the image as seen on screen. It will, however, be appreciated that other mirror types may be used to achieve a similar effect. 
     The reflective member  40  may alternatively be a prism  80  as shown in  FIG. 3 . The prism  80  has an inner reflective surface  82  set at an angle of approximately 45° from the internal surface  50  of the housing  12  and facing the proximal end  14  of the housing  12 . The prism  80  shown is a right-angled prism having a first surface  84  positioned substantially parallel to a longitudinal axis of the housing  12  and a second surface  86  positioned substantially perpendicular to the longitudinal axis. As described above in the context of a mirror, the inner reflective surface  82  could alternatively be set at an angle of between 30°, 35° or 40° and 50°, 55° or 60° to the internal surface  50  of the housing  12 . If the angle of orientation of the inner reflective surface  82  is changed, the orientation of the first  84  and second  86  surfaces is changed accordingly to provide appropriate angles of refraction between the object  100  and the sensor  20 . 
     One edge of the prism  80  is positioned partway through the opening  18  of the housing in line with an edge of the housing  12 . The edge of the prism  80  is positioned away from the internal surface  50  of the housing to which the projection is attached at a distance between 30%, 35%, 40% or 45% and 55%, 60%, 65% and 70% of the diameter, d, of the opening. In a particular embodiment, the edge of the prism is positioned away from the internal surface of the housing at a distance approximately 50% of the diameter of the opening. It will be appreciated that where the opening has a different shape, e.g. a square, the distance will be calculated to be a percentage of the distance between two opposing internal walls. 
     The lens  20  shown in  FIGS. 1 and 2  are positioned substantially perpendicular to a longitudinal axis of the housing such that the centre of the lens coincides with a point on the longitudinal axis. The sensor  22  is located between the lens  20  and the proximal end  14  of the housing at some point along the longitudinal axis in line with the centre point of the lens  20 . It will, however, be appreciated that the relative positions of the lens and sensor could be different if the lens is arranged to focus onto a different position. Furthermore, multiple sensors and/or lenses could be provided. For example, multiple lenses may be used to provide multiple magnification levels/points. In embodiments, the lens may be bi-focal to ensure that both parts of the image are kept in focus. Additionally, multiple sensors may be used, for example, to detect different colors in the images. 
     To focus the image on an object to be viewed, the lens  20  is movable between the proximal  14  and distal  16  ends of the housing. The lens  20  may be moved by means of a rack and pinion mechanism, where a rotational member  90 , located on the outside of the housing  12 , is rotated by a user to result in longitudinal movement of the lens towards or away from the object to be viewed. Other known methods of converting rotational movement to longitudinal movement could similarly be used. Alternatively, a lever (not shown) could be attached to the lens and placed outside the housing  12  to enable a user to slide the lens  20  towards or away from the object to be viewed. 
     To ensure that objects being viewed are illuminated, the distal end of the housing may be formed of clear material. Alternatively, and/or additionally, one or more light sources  78 , shown in  FIG. 3 , may be provided within the housing for illuminating the object to be viewed. Alternatively, and/or additionally, the distal end  16  of the housing could be formed of a clear material. 
     In the previously described embodiments, the projection  42  and reflective member  40  are affixed to an internal surface  50  of the housing  12 . It will, however, be appreciated that other means for securing the reflective member  40  in place may be used. For example, in an alternative embodiment, shown in  FIG. 4 , the projection is formed integrally with a detachable cap  110  for affixing to the opening  18  of the housing  12 . The cap  110  has an open end  112  such that when the cap is fixed to the housing, the open end  112  of the cap  110  is perceived to be the opening  18  of the housing  12 . 
     The detachable cap  110  has an external wall  114 , the contour of which corresponds with the contour of the internal surface  50  of the opening  18  of the housing  12  such that the cap  110  forms a snug fit with the housing  12  and is accordingly retained in place. Alternatively, the cap may be affixed to the housing by other known means, for example, in the form of a screw-cap or by providing correspond male and female components on the cap and housing respectively that are fit together to secure the cap to the housing. 
     The cap  110 , with projection  42 , may be made from plastic, metal, foam, wood or any other known material. Depending on the material of the cap  110 , the cap may be made from injection molding, rapid prototyping, or other known methods. For example, as an alternative, the cap may be machined from stock material and the cap may be made from e.g. nylon. In particular embodiments, the cap is made of a material that can be wiped clean or sterilized, or the cap may be made of material that enables it to be disposable. 
     An application of the digital microscope described above may be to look at the surface of skin. In use, a user could press the opening  18  of the microscope, or the open-end  112  of the cap, against an area of skin with the intention that some of the skin would bulge through the opening.  FIG. 2  shows an example of skin bulging through the opening and illustrates how light reflected from the surface of the skin is directed to the sensor to result in a bi-directional view of the skin from directly above, direction P, and from the side, direction Q. 
     Specifically, light is reflected from the skin in general directions A and B towards the sensor  22 . In direction A, light is reflected directly onto the lens  20  and focused onto the sensor  22 . By contrast, in direction B 1 , light is reflected onto the reflective member  40  and subsequently reflected in direction B 2  onto the lens  20  for focusing onto the sensor  22 . Light that is reflected directly to the lens  20  is shown in one side of the image A, and light reflected from the reflective member to the lens  20  is shown in the other side of the image B. 
     The bi-directional view provided by the digital microscope described above is particularly useful for looking at hairs growing through, on or beneath skin and for gaining a topographical appreciation of the interaction between skin and hair. For example, the microscope can be used to look at the topography of skin, ingrown hairs or facial anomalies. 
     The dimensions and values disclosed herein are not to be understood as being strictly limited to the exact numerical values recited. Instead, unless otherwise specified, each such dimension is intended to mean both the recited value and a functionally equivalent range surrounding that value. For example, a dimension disclosed as “40 mm” is intended to mean “about 40 mm. ” 
     Every document cited herein, including any cross referenced or related patent or application, is hereby incorporated herein by reference in its entirety unless expressly excluded or otherwise limited. The citation of any document is not an admission that it is prior art with respect to any invention disclosed or claimed herein or that it alone, or in any combination with any other reference or references, teaches, suggests or discloses any such invention. Further, to the extent that any meaning or definition of a term in this document conflicts with any meaning or definition of the same term in a document incorporated by reference, the meaning or definition assigned to that term in this document shall govern. 
     While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention.