Abstract:
A portable apparatus having a source, a detector and a filtering element placed a known distance from the source and/or the detector. One embodiment of the apparatus is a headlamp having an illumination source, a camera, and two eye pieces. The headlamp has an adjustable headband for positioning the headlamp on the head of the user and a protective cover for interacting with the camera, eye pieces, and/or illumination source. The protective cover preferably includes multiple sets of filtering elements such that motion about or along an axis changes the filtering elements interacting with the camera, eye pieces, and/or the illumination source.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    The present application, pursuant to 35 U.S.C. 111(b), claims the benefit of the earlier filing date of provisional application Ser. No. 60/922,823 filed Apr. 11, 2007, and entitled “Filter Set Holder” and provisional application Ser. No. 60/925,222 filed Apr. 19, 2007, and entitled “Headset Mounted Apparatus Mounting a Face Visor with Selectably Interchangeable Optical Filters for Viewing Irradiated Surfaces.” 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The invention relates to a portable medical examination apparatus having an illumination source, a detector, and a filter set positioned a known distance from the source and/or the detector. More particularly, the present invention relates to a head mounted apparatus having an illumination source, a camera, two eye pieces, and a protective face visor having multiple sets of filtering elements such that motion about or along an axis changes the filtering elements interacting with the camera, the eye pieces, and/or an illumination source. 
         [0004]    2. Description of the Related Art 
         [0005]    Cervical cancer is the second most common malignancy in women worldwide. The mortality associated with cervical cancer can be reduced if this disease is detected at the early stages of development or at the pre-cancerous state. A pap smear is used to screen the general female population for cervical cancer with more than 70 million performed each year in the United States. In spite of its broad acceptance as a screening test for cervical cancer, pap smears probably fail to detect 50-80% Of low grade cancerous lesions and about 15-30% of high grade lesions. 
         [0006]    While the pap smear is designed for initial screening, colposcopy and related procedures are typically used to confirm pap smear abnormalities and to grade cancerous and potential cancerous lesions. Although it is generally recognized that colposcopy is highly effective in evaluating patients with abnormal pap smears, colposcopy has its own limitations. Conventional colposcopy is a subjective assessment based on the visual observation of the clinician and the quality of the results depends greatly on the expertise of the practitioner. 
         [0007]    Commercially available colposcopes are large free-standing instruments and are generally maintained in a single location (i.e., one examination room). Furthermore, colposcopes are expensive and are typically shared by multiple doctors. Accordingly, when a colposcopic examination is required, the patient has to be brought to the colposcope. Based on the limited availability of the colposcope, a special appointment time separate from the initial appointment is usually required resulting in additional time and cost to a patient as well as delayed examinations. 
         [0008]    Accordingly, a portable apparatus, which allows for a close-up visual medical examination would be advantageous for providing an examination without relocation of the patient or providing a separate appointment time. Such an apparatus would be readily useable and economical, thereby making diagnosis and treatment more readily available and cost efficient. 
       SUMMARY OF THE INVENTION 
       [0009]    One embodiment of the invention is a portable examination apparatus comprising: a head mountable frame; an illumination source mounted on the frame, the illumination source configured to illuminate a tissue with radiation; an illumination filter in operative relation with the illumination source, wherein the radiation generated by the illumination source passes through the illumination filter before illuminating the tissue; a detector mounted on the frame, the detector configured to collect radiation emanating from the tissue illuminated with the illumination source; a detection filter in operative relation with the detector, wherein the radiation emanating from the tissue passes through the detection filter before being collected by the detector; and a selectably operable visor, wherein the visor includes a visor screen that incorporates the illumination filter and the detector filter. 
         [0010]    A second embodiment of the invention is a medical examination apparatus comprising: a head mountable frame; an illumination source mounted on the frame, the illumination source configured to illuminate a tissue with radiation; an illumination filter in operative relation with the illumination source, wherein the radiation generated by the illumination source passes through the illumination filter before illuminating the tissue; a detector mounted on the frame, the detector configured to collect radiation emanating from the tissue illuminated with the illumination source; a detection filter in operative relation with the detector, wherein the radiation emanating from the tissue passes through the detection filter before being collected by the detector; two eye pieces mounted on the frame, the eye pieces configured to visualize the radiation emanating from the tissue illuminated with the illumination source; a pair of eye piece filters in operative relation with the eye pieces such that the radiation emanating from the tissue passes through the eye piece filters before passing to the eye pieces; a selectably operable visor, wherein the visor includes a visor screen that incorporates multiple sets of filtering elements, each set of filtering elements includes the illumination filter, the detector filter, and two eye piece filters; and a positioning mechanism for positioning a selected set of filtering elements such that the selected illumination filter is aligned with the illumination source, the selected detector filter is aligned with the detector, and the selected eye piece filters are aligned with the eye pieces. 
         [0011]    A third embodiment of the present invention is a portable medical examination apparatus comprising: (a) a head mountable frame; (b) an illumination source mounted on the frame, the illumination source configured to illuminate a tissue with radiation; (c) a detector mounted on the frame, the detector configured to collect radiation emanating from the tissue illuminated with the illumination source; (d) a pair of eye pieces mounted on the frame, the eye pieces configured to visualize the radiation emanating from the tissue illuminated with the illumination source; (e) a visor incorporating a first and a second set of filtering elements in a visor screen, wherein each set of filtering elements includes an illumination filter, a detection filter and two eye piece filters; and (f) a mechanism for reciprocating the visor screen between a first position and a second position, wherein when the visor screen is in the first position the illumination filter of the first set of filtering elements is aligned with the illumination source such that the radiation generated by the illumination source passes through the illumination filter of the first set of filtering elements before illuminating the tissue, the detection filter of the first set of filtering elements is aligned with the detector such that the radiation emanating from the tissue passes through the detection filter of the first set of filtering elements before being collected by the detector, and the pair of eye piece filters of the first set of filtering elements is aligned with the pair of eye pieces such that the radiation emanating from the tissue passes through the pair of eye piece filters of the first set of filtering elements before passing to the eye pieces, and when the visor screen is in the second position the illumination filter of the second set of filtering elements is aligned with the illumination source such that the radiation generated by the illumination source passes through the illumination filter of the second set of filtering elements before illuminating the tissue, the detection filter of the second set of filtering elements is aligned with the detector such that the radiation emanating from the tissue passes through the detection filter of the second set of filtering elements before being collected by the detector, and the pair of eye piece filters of the second set of filtering elements is aligned with the pair of eye pieces such that the radiation emanating from the tissue passes through the pair of eye piece filters of the second set of filtering elements before passing through to the eye pieces. 
         [0012]    The foregoing has outlined rather broadly several aspects of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and the specific embodiment disclosed might be readily utilized as a basis for modifying or redesigning the structures for carrying out the same purposes as the invention. It should be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which: 
           [0014]      FIG. 1  is a side view of a first embodiment of a medical examination device, wherein the device is mounted on a human head and the visor is in position for filtering light passing through the visor. 
           [0015]      FIG. 2  corresponds to  FIG. 1 , but shows the visor in position where it is out of the line of vision for the operator. 
           [0016]      FIG. 3  is an oblique frontal view of the headpiece of the first embodiment of the examination device seen in  FIG. 1 . 
           [0017]      FIG. 4  is an exploded view of the headpiece of  FIG. 3 . 
           [0018]      FIG. 5  is a partial vertical longitudinal section of the headpiece of  FIG. 3 , wherein the housing and the front portion of the headpiece are sectioned. 
           [0019]      FIG. 6  is an oblique rear view of the visor for the examination device of  FIG. 1 , wherein the visor screen is selectably scrolled so that a set of filters are arranged to provide filtering for light passing through the visor. 
           [0020]      FIG. 7  is an exploded view of the visor of  FIG. 6 , wherein the visor screen is scrolled to position a first set of filters in an active, exposed position. 
           [0021]      FIG. 8  corresponds to  FIG. 7 , but has the visor screen scrolled so that a second set of filters are in an active, exposed position. 
           [0022]      FIG. 9  is an oblique frontal view showing the headpiece of a second embodiment of the medical examination device. 
           [0023]      FIG. 10  is an oblique rear view of the visor for the examination device of  FIG. 9 , wherein the visor screen is. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0024]    The invention relates to a portable examination apparatus having a head mountable frame, an illumination source, a detector, and a selectably operable protective shield, or face visor. The visor incorporates an illumination filter and a detector filter such that whenever the visor is engaged the illumination filter will interact with the radiation generated by the illumination source and the detector filter will interact with the radiation emanating from a sample illuminated with the illumination source. The term “radiation” is herein defined as “waves or particles such as light, sound, radiant heat, or particles emitted by radioactivity.” The term “light” is herein defined as any electromagnetic radiation and includes photons, gamma rays, x rays, ultraviolet radiation, visible light, infrared radiation, microwaves, radio waves, heat, and electric current. 
         [0025]    Examination Device  100   
         [0026]      FIGS. 1 and 2  illustrate a first embodiment of a head mounted examination device  100 . The examination device  100  is structured to be positioned on the head of the user or operator  20  as shown in  FIG. 1 . This allows the operator versatility in positioning and viewing during an examination of a sample such as a tissue sample. The examination device  100  includes a protective shield or visor  200  mounted on a headpiece  110 . 
         [0027]    The headpiece  110  includes an adjustable head mount and a frame  138  mounting an illumination source  122  and a detector  120 . 
         [0028]    The adjustable head mount positions the examination device  100  on the head of the operator  20 . The head mount includes a thin, flexible plastic ring  112  of an approximately elliptical shape for fitting horizontally on the head of a user. The head mount horizontal ring  112  is provided with padding and has a horizontal adjustment screw  114  for adjusting the effective circumference of the ring to fit different head sizes. A preferred method of making the horizontal adjustment is to split the horizontal ring at the rear of the headpiece and to provide overlapping tabs which can be clamped rigidly together by the adjustment screw mounted in a sleeve enclosing the tabs. A second method of making the adjustment is to split the horizontal ring at the rear of the headpiece and to provide overlapping tabs having racks of gear teeth on their facing horizontal edges. This second means then uses a pinion gear (not a screw) on the shaft of the adjustment means to engage the opposed linear gear racks to cause the effective circumference of the horizontal ring when the adjustment means is rotated. The adjustment means is journaled in a sleeve surrounding the overlapping tabs. 
         [0029]    A roughly semicircular across head strap  116  lies in the vertical plane and joins two opposed sides of the horizontal ring  112  by passing over the head near the ears. The across head strap  116  is also provided with a length adjustment of the same type as for the head mount horizontal ring  112 . Both these adjustment means enable the flexible head mount to be adjusted to any head so that the illumination source  122 , the detector  120 , and the optional eyepieces  124  will be correctly aligned for the operator&#39;s use. Adjusting the head mount to fit the individual operator will stabilize the headpiece  110  so that the headpiece will maintain its position on the operator&#39;s head despite changes of head position. 
         [0030]    The frame  138  of the examination device  100  is mounted on the forward side of the adjustable head mount and is typically constructed of relatively rigid injection-molded plastic materials. The frame includes a mounting bracket  140  and a main housing  150  for the attachment of the illumination source  122 , as best seen in  FIGS. 3 and 4 . The mounting bracket  140  is a symmetrical thin element constructed of vertical flat elements. The middle of the mounting bracket is a central flat perpendicular to the long axis of the ellipse of the headpiece ring, and it is joined at its ends to the front of the head mount by two flat side elements angularly offset from the central flat. The central flat has a horizontal axis screw hole at its middle, while a larger coaxial hole in the headpiece horizontal ring  112  provides access to the head of a mounting screw  142  that is engaged through the screw hole and used for attaching the housing  150 . 
         [0031]    A transverse horizontal hole penetrates both side elements of the mounting bracket  140  above the midheight of the mounting bracket. The penetrations are provided with outwardly extending reinforcing mounting bosses  148 . 
         [0032]    The main housing  150  provides mounting for an illumination source  122  for illuminating the sample or tissue surface under investigation with radiation, a detector  120  for collecting and/or recording the radiation emanating from the sample illuminated with the illumination source, and a pair of optional eye pieces  124 . 
         [0033]    The main housing  150  includes a short horizontal open-top section projecting forward from an end bulkhead having two horizontally outwardly extending short transverse rectangular ears. The forwardly projecting open-top section is cojoined by a forwardly and downwardly curving approximately 90° arcuate section having an open side on its outer arcuate side, ending in an intersecting integral forwardly extending tubular emitter housing  144 . 
         [0034]    An inwardly extending centrally positioned drilled and tapped boss in the end bulkhead permits mounting the main housing  150  to the mounting bracket  140  of the headpiece  110  by means of the mounting screw  142 . The trough formed by the horizontal and arcuate sections of the main housing  150  opens into the tubular emitter housing  144 . A female helical thread on the forward end of the emitter housing  144  permits the threaded attachment of an emitter lens  133  to assist in focusing the emitted radiation from the illumination source  122  into a narrow beam for impingement onto the tissue sample. 
         [0035]    Interior and concentric to the bore of the emitter housing  144  is a transverse disk upon which an outwardly, forwardly facing illumination emitter  132  is mounted. A preferred embodiment uses a light emitting diode (LED) as the illumination emitter  132 , as shown in  FIG. 4 . The LED is selected to emit light with a desired predominant wavelength. The emitter lens  133  focuses the emitted light into a narrow beam which is projected forward. An adjustment lever or mechanism  126  is horizontally positioned above the emitter housing  144  to serve as a means of focusing the light beam of the LED (mechanism not shown). 
         [0036]    A preferred embodiment of the examination device  100  has two eye pieces  124  attached to the main housing  150  as illustrated in  FIGS. 3 and 4 . The eye pieces  124  have a field of view that is substantially similar to the field of view of the detector. An eye piece support bar  125 , mounted transversely to the main housing  150  on its lower horizontal side, is generally symmetrical about the vertical longitudinal midplane of the examination device  100 . A vertical hole on the lower horizontal side of the horizontal segment of the main housing  150  permits the attachment of an eye piece support bar  125  by means of a screw and nut. The eye piece support bar  125  has an elongated constant cross-section with a horizontal midsection having a central vertical through hole for mounting purposes and downwardly offset horizontal outwardly extending arms having elongate slots for mounting of an eye piece  124  on each end of the eye piece support bar  125 . The axes of the eye pieces  124  are preferably mounted at about the same elevation as the axis of the tubular emitter housing  144 . 
         [0037]    Preferably two eye pieces  124  are used, one for each eye, with the eye pieces symmetrically positioned on opposed ends of the eye piece support bar  125  as shown in  FIGS. 3 and 4 . The eye pieces  124  typically have short right circular cylindrical outer ends cojoined by frustroconical inner end segments which reduce in size towards the head mount. The eye pieces  124  have inclined pylons upwardly extending in a radial plane. The eye piece pylons have a distal transverse horizontal projection for maintaining alignment of the eyepiece perpendicular to the horizontal axis of the slots of the eyepiece support bar  125 . The upper ends of the pylons are provided with vertical drilled and tapped holes so that each eye piece  124  can be mounted to the eyepiece support bar  125  by means of a clamp screw  146 . The slots of the eyepiece support bar  125  permit the eye pieces  124  to be aligned with the individual eyes of an observer  20 . Preferably, the eye pieces  124  are provided with internal lenses to provide magnification for their field of view. 
         [0038]    A small forwardly facing detector  120  is mounted inside the main housing  150  to record the image of the illuminated surface. The detector  120  collects and/or records the radiation emanating or reflected from the tissue illuminated with the illumination source  122 . A preferred embodiment of the detector  120  is a digital camera, although the detector  120  may also be a television camera or a conventional still camera. One embodiment of the examination device  100  will couple the camera with an imaging element (not shown). 
         [0039]    Both the detector  120  and the illumination emitter  132  are provided with power by means of a communication cable  130  having power cords for the detector  120  and illumination emitter  132 . In a preferred embodiment, the communication cable  130  will include a power cord for the detection camera, a communication cord for the imaging element, and a power cord for the LED illumination emitter  132 . 
         [0040]    A horizontal hole penetrates the side of the main housing  150  at approximately midheight near to the end bulkhead. This horizontal hole serves to mount a detector focus knob  128  which extends into the interior of the main housing  150 . The detector focus knob  128  engages a focusing mechanism (not shown) for the detector  120  which is mounted in the interior of the main housing  150 . 
         [0041]    A cover  134  is provided for the open-top section of the main housing  150 . The cover  134  has a horizontal inner end and an arcuate outer end. The flat horizontal inner section of the cover  134  is engaged structurally to the top flat open-top section of the main housing  150  by means of a snap fit between the grooves of the main housing  150  and outwardly extending male ridges on vertical projections of the cover  134 . The opposed arcuate interior vertical walls of open-top arcuate section of the main housing  150  have grooves adjacent their outer arcuate edges for engagement with comateable ridges provided with the arcuate outer end of the cover  134 . 
         [0042]    The inner distal end of the cover  134  has a short central notch for permitting passage of the communication cable  130 . The arcuate outer end of the cover  134  has an aperture for the detector  122 . For embodiments of the examination device  100  using a camera as the detector  122 , this aperture has an inwardly extending cylindrical boss concentric with the lens of a camera when the cover  134  is assembled to the main housing  150 . 
         [0043]    The inner distal end of the cover  134  is perforated with multiple slots to permit cooling of the interior of the main housing  150 . The partial longitudinal vertical cross-section of the lamp unit and mounting bracket of the headpiece shown in  FIG. 5  indicates the relative positions of the elements of the assembled headpiece  110 . 
         [0044]    One embodiment of the visor  200 , shown in  FIG. 6 , is typically made of a clear semirigid plastic sheet. The visor screen  210  has at least an illumination filter  206   a  and a detector filter  202   a  embedded in the visor screen  210 . A preferred embodiment of the visor  200  includes two eye piece filters  204   a.  The filters are also made of a clear semirigid plastic sheet having the same stiffness properties as those of the visor screen  210 . Although the filters may be transparent, the filters are generally configured to select the passage of a particular wavelength of radiant energy. For example, the eye piece filters  204   a  may be modified to allow the passage of a certain wavelength of visible electromagnetic radiation, or the illumination filter  206   a  may be modified to pass only ultraviolet light or some other desired wavelength. The visor  200  may also have an optional triggering mechanism for signaling the detector  220  and/or the illumination source  122  of the position of the visor screen  210  and the filters aligned with the detector  220  and/or the illumination source  122 . 
         [0045]    The visor  200  is seen in an oblique rear view in  FIG. 6  and in exploded views in  FIGS. 7 and 8 . The visor  200  consists of a frame  220  symmetrical about a vertical midplane and having two vertical roll housings  216 , a lower horizontal arcuate track  214 , a left and a right spindle  212 , and a spoolable flexible transparent visor screen  210  having integral filter elements. 
         [0046]    The frame  220  has a horizontal arcuate upper track  222  having the same curvature as the lower arcuate track  214 , wherein the upper track  222  cojoins the opposed vertical roll housings  216 . Each roll housing  216  has an open lower end and an upwardly opening central hole which journals the upper end of the shaft of the spindle  212 . 
         [0047]    Symmetrically opposed horizontal arcuate support arms  226  extend straight back and then curve inwardly so that they are normal to and outwardly offset from the vertical midplane of the frame  220 . The opposed inwardly facing ends of the support arms are provided with opposed holes which house a horizontal shaft  218  which cojoins the two support arms. The horizontal shaft  218  is deployed in the transverse penetrations reinforced with the mounting bosses  148  in the mounting bracket  140  of the headpiece  110  so that the visor can be pivoted selectably between its operating position shown in  FIG. 1  and its retracted position shown in  FIG. 2 . 
         [0048]    The lower track  214  is a mirror image of the upper track  222 , and both tracks have arcuate horizontal grooves for guiding engagement and support of the horizontal edges of the spoolable visor screen  210 . The distal ends of the lower track have short stepped integral right circular cylinders  232 , wherein the smaller diameters of the cylinders are snuggly engaged into the bores of the roll housings  216  for retention and the larger diameters are the same as the outer diameters of the roll housings. The cylinders of the lower track have coaxial through holes which journal the shafts of the spindles  212 . 
         [0049]    The roll housings  216  have vertical exit slots which are aligned with the horizontal grooves of the upper and lower tracks. The spindles  212  have elongate vertical right circular cylindrical shafts with a snap ring groove at their upper ends and manual rotation knobs at their lower ends. The central portions of the spindles  212  are provided with clamps or slots for fixedly engaging the opposed vertical ends of the spoolable visor screen  210 . The spoolable visor screen is engaged between the upper ends of the roll housings  216  and the upper ends of the cylinders  232  of the lower track  214 , while the knobs of the spindles  236  are exposed on the lower side of the lower track. The spindles  212  are retained by snap rings in their upper grooves, as seen in  FIGS. 7 and 8 . 
         [0050]    In a preferred embodiment of the visor  200  a set of three holes in a horizontal plane with an upwardly vertically offset central hole house four filters at one or more positions in the spoolable visor screen  210 . The filters are generally treated to selectively pass only certain wavelengths of light. Although the filters may be any shape, the detector filter  202   a  and/or the illumination filter  206   a  are typically circular in shape when flat. The eye piece filters  204   a  may also be circular, but may they will often take on an elliptical shape to account for some variation in the positioning of the eye pieces  124 . 
         [0051]    The visor screen  210  contains one or more set of filters. For example,  FIG. 6  illustrates a set of four filters (i.e., two eye piece filters  204   a,  an illumination filter  206   a , and a detector filter  202   a ). These filters are positioned so that, when spooled into position the illumination filter  206   a  is located directly in front of the illumination emitter  132 , the eye piece filters  204   a  are positioned directly in front of the eye pieces  124 , and the detector filter  202   a  is positioned directly in front of the detector  120 . Different filters are generally used for the two eye piece filters  204   a,  the illumination filter  206   a,  and the detector filter  202   a  depending on the wavelength of radiation selected for emission and the wavelength desired for observation. 
         [0052]    The use of multiple sets of filters embedded in a scrollable visor screen  210  permits multiple types of observation with the same visor  200 . In order to change the wavelengths for a different type of inspection or observation, the observer  20  can spool the visor screen  210  to select the desired filter set or no filter set.  FIGS. 7 and 8  show the visor screen having at least two sets of filters. The first filter set shown in  FIG. 7  includes two eye piece filters  204   a,  an illumination filter  206   a,  and a detector filter  202   a.  As the visor screen  210  is spooled toward the right in  FIG. 8 , a second set of filters begins to appear (i.e., two eye piece filters  204   b,  an illumination filter  206   b,  and a detector filter  202   b ). 
         [0053]    An optional feature of visor  200  is to have a mechanical, electronic and/or electromechanical signal for specific filter sets embedded in the visor screen that will trigger configuration changes in the illumination source  122  and/or detector. For example,  FIGS. 7 and 8  illustrate a simple system for signaling between two filter sets.  FIG. 7  illustrates two horizontal bars to the right of the first set of filters  202   a,    204   a  and  206   a.  The upper bar  602   a  is transparent and the bottom bar  602   b  is made of a metallic conductive material.  FIG. 8 , on the other hand, illustrates two horizontal bars to the right of the second set of filters  202   b,    204   b  and  206   b.  The upper bar  604   a  is the metallic conductive material and the bottom bar  604   b  is transparent. 
         [0054]    Thus, when the first filter set is in position the metal conductive material of the lower bar  602   b  can complete a circuit to signal turning on a switch to activate a predetermined illumination source configuration and/or a detector configuration. For example, the signal may activate a first light source (e.g., a particular LED of several LEDs) in the illumination source and/or a predetermined operating condition for the light source (e.g., a predetermined wattage). The signal may also activate a first detector (e.g., a particular detector of several detectors) or a particular detector configuration (e.g., a particular exposure time for the detector). In contrast, when the second filter set is in position the metal conductive material of the upper bar  604   a  will signal the turning on of a switch to activate a second light source and/or operating condition of the illumination source and/or a second detector and/or configuration of the detector. 
         [0055]    Examination Device  400   
         [0056]    A second embodiment of the examination device  400  is shown in  FIGS. 9-13 . The primary structural components of the headpiece  410  of the examination device  400  are basically the same as for the examination device  100 , except that the visor  500  is mounted and arranged differently than for the examination device  100 . The structural difference for the headpiece  410  is the elimination of the transverse holes through the mounting bracket  140  for the support of the shaft  218  of the visor  200 , rather the cover  434  for the headpiece  410  has a reinforcing boss on the longitudinal midplane projecting outwardly at an angle from the horizontal and supporting a coaxial centrally positioned inclined pivot shaft  460 , as seen in  FIG. 9 . Otherwise, the headpiece  410  and the main housing  450  are the same as for the examination device  200 . 
         [0057]    The visor  500  also differs from the visor  200 . The visor  500  is a concave arcuate element formed by rotating a symmetrical cross-section equal amounts in both directions about a horizontal transverse axis so that the visor extends over approximately 100° to 120°. The cross-sectional profile can have a constant width or, alternatively, it can be tapered to reduce in width towards its distal ends. The symmetrical cross-section can be either a circular arc, a portion of an elliptical profile, or a straight central segment with inwardly inclined straight or curved side segments. The intersection of the two planes of symmetry of the visor  500  forms an axis of rotation for the visor. A short inwardly extending cylindrical boss  510  has a central coaxial cylindrical hole which closely fits the pivot shaft  460  mounted on the cover  434  of the main housing  450 . 
         [0058]    The visor  500  is provided with one or more sets of holes in the same pattern as those in the first visor so that sets of filters can be mounted therein. The material of the second visor is a transparent rigid plastic. As the case for the filters of the first visor, the second filters are of the same material as the second visor, but with the addition of either surface coatings or modifications so that they selectively pass only certain wavelengths of light. 
         [0059]    The visor  500  contains one or more filter sets. For example,  FIG. 10  illustrates visor  500  with two filter sets. The first set is shown in position such that the two eye piece filters  504   a  are positioned directly in front of the eye pieces  124 , the illumination filter  506   a  is located directly in front of the illumination source  122 , and the detector filter  502   a  is positioned directly in front of the detector  120 . Different filters are generally used for the two eye piece filters, the illumination filter, and the detector filter depending on the wavelength of radiation selected for emission and the wavelength desired for observation. 
         [0060]    The use of multiple sets of filters permits multiple types of observation with the same visor  500 . In order to change the wavelengths for a different type of inspection or observation, the observer  20  can rotate the visor  500  about the pivot shaft  460  to select the desired filter set or no filter set.  FIG. 10  shows the visor  500  having two sets of filters. The first filter set shown in  FIG. 10  includes two eye piece filters  504   a,  an illumination filter  506   a,  and a detector filter  502   a.  As the visor  500  is rotated about the pivot shaft  460 , a second set of filters can be positioned for observation (i.e., two eye piece filters  504   b,  an illumination filter  506   b,  and a detector filter  502   b ). 
         [0061]    An optional feature of visor  500  is to have a mechanical, electronic and/or electromechanical signal for specific filter sets embedded in the visor screen that will trigger configuration changes in the illumination source  122  and/or detector. For example, the rotation of the visor  500  and its boss  510  could rotate the pivot shaft  460  and mechanically change the configuration of the illumination source and/or detector. The configuration changes induced by the rotation of the pivot shaft  460  can change the type of illumination source (e.g., visible to ultra violet illumination) and/or detector (e.g., digital camera to a television camera), or rotation of the shaft can change the settings of the illumination source (e.g., the wattage going to an LED illumination source) and/or the detector (e.g., the exposure time or zoom on a digital camera). 
       OPERATION OF THE INVENTION 
       [0062]    The operation of the two embodiments illustrated is identical in most respects, differing only in the adjustment of the visor for using different filter sets. The first examination device  200 , shown in  FIGS. 1 to 8 , and the second examination device  400 , shown in  FIGS. 9 and 10 , operate the headpiece identically. 
         [0063]    When a new observer  20  dons the examination device, he adjusts the lengths of the across head band  116  and the around head band  112  so that the device snuggly fits his head and the axes of the eyepieces are properly aligned with his eyes. If necessary, the offset of the eyepieces from the midplane can be adjusted by loosening the clamp screws, shifting the eyepieces laterally down the slots of the eye piece support bar, and then reclamping. 
         [0064]    Normally, power for operating the device is provided by a battery pack (not shown) mounted on a belt or free standing and connected to the viewing device by the power cord. The power can be switched on by a switch on the battery pack. However, the device may also have a cord for plugging the examination device into a power outlet. 
         [0065]    When the power is switched on, the visor is moved into its viewing position and the desired filter set is positioned in front of the apertures of the examination device. With the visor  200  the filter set is positioned by appropriately rotating the knobs of the spindles  212  of the visor  200 . The visor  200  can be raised at any time for unobstructed viewing and then selectably returned to its operational position, as seen in  FIGS. 1 and 2 . In the case of the visor  400  the filter set is positioned by rotating the visor  400 . 
         [0066]    Once the visor is positioned and the proper filter set is aligned with the appropriate illumination source and detector, the focus of the illumination source and the detector can be independently adjusted using the adjustment mechanism  126  and the camera focus knob  128 . When illumination sources and/or detectors are used that do not require focusing, the adjustment mechanism  126  and/or the focus knob  128  may not be necessary. 
         [0067]    Depending upon which set of filters, if any, is present in front of the viewing device, the emitted light from the illumination emitter  132  passes through the middle illumination filter  206   a  in the lower set of three filters. The beam of this filtered light strikes the tissue sample to be observed. The impinging light is partially reflected, and some of the light may cause fluorescence on the surface of the observed object. Some portion of the reflected light and any fluorescence impinge on the right and left filters of the visor, with a portion of the this impinging light selectively passing through those filters to the eyepieces and thence to the eyes of the observer. 
         [0068]    Similarly, another portion of the reflected light and any fluorescence will impinge on the upper detector filter  202   a  in the filter set of the visor  200 . This filtered light is selectively filtered by the detector filter and then sensed by the detector. 
         [0069]    The operation of the examination device  400  is substantially similar to the operation of the examination device  200  except for the operation of the visor  500 . The visor  500  is selectably rotated about the pivot shaft  460  seen in  FIG. 9  so that the desired filter set is in alignment with the axes of the apertures of the viewing device. The visor  500  can also be rotated so that no filtering is provided by the visor  500 . As is the case for the first visor, when a filter set is aligned with the lamp assembly, the emitted light is filtered. Any light emanating from, reflected from and/or fluorescing from the illuminated surface is filtered when passing through the right and left filters to the eyepieces and by the detector filter when passing through to the detector. 
         [0070]    For both embodiments, the visors also promote sanitation by providing a degree of isolation between the observer and the observed surface. 
       ADVANTAGES OF THE INVENTION 
       [0071]    The examination devices of the present invention offer a simple, inexpensive, convenient, and effective means of using various wavelengths of light, including ultraviolet light, for the visual inspection of a surface. The viewing devices are light weight, generally robust in construction, and easy to clean and service. The provision of a visor provides a sanitary and protective barrier between the observer and the viewed object surface. One advantage of the examination devices is their simple positioning adjustment for the alignment of different filter sets for the emitted and received light beams. An additional advantage is the easy means of adjusting the visor so that the viewed object surface can be seen without filtering. 
         [0072]    It should be appreciated by those skilled in the art that the conception and the specific embodiment disclosed might be readily utilized as a basis for modifying or redesigning the structures for carrying out the same purposes as the invention. It should be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims.