Related Applications

This application is based on and claims the benefit of the filing and priority dates of AU patent application no. 2016901997 and US patent application no. 62/341 ,681 , both filed 26 May 2016, the content of both of which as filed is incorporated herein by reference in its entirety.

Field of the Invention

The present invention relates generally to imaging apparatuses, such as

dermatoscopes and otoscopes, for viewing and imaging tissue such as skin, including for the detection of and research relating to melanoma and other skin conditions, and in particular to an optical accessory for facilitating the operation of a mobile telephone as a dermatoscope or otoscope.

Background of the Invention

Dermatoscopes are optical devices for examining skin. They typically include a light source, a magnifier and a transparent contact plate, and are generally handheld. In use, a liquid medium may be applied between the contact plate and the skin to minimize skin surface reflections. Some dermatoscopes use polarized light to further minimize skin surface reflections. Otoscopes are optical devices for examining the eardrum and other portions of the outer ear.

Summary of the Invention

According to a first broad aspect of the invention, there is provided an optical module comprising:

a body with a front face (which may, but need not always, define an image plane) and a rear face, and defining a first passage and a second passage between the front face and the rear face; and

an optical train of one or more optical elements located in the first passage; wherein the optical module is adapted to be attached to a mobile computing device such that the first passage is located over an entrance aperture of a camera of the mobile computing device and the second passage is located over a light source of the mobile computing device;

the first passage and the second passage are located (such as by being substantially coincident or substantially concentric) at the front face such that light from the light source and traversing the second passage illuminates a specimen (which, in some cases, may be adjacent to the front face) and such that return light from the specimen and traversing the first passage is received by the optical train; and

the optical train is configured to form an image of the specimen that is imagable by the camera of the mobile computing device.

It will be appreciated by those skilled in the art that the first and second passages, being optical passages, may include optically transparent material— such as lenses the case of the first passage. It will also be appreciated that the first and second passages need not be straight; for example, light may be deflected by one or more optical elements, the walls of the passage or otherwise so as to follow the respective passage.

It is envisaged that the optical module may be produced economically and provide users with the ability to image— for forming possibly a preliminary diagnosis— of specimens such as skin or ears.

It is also envisaged that the module would be issued in conjunction with suitable analysis software (executable on the mobile computing device) for analysing images collected with the module.

In an embodiment, the optical module comprises a fastener for attaching the optical module to the mobile computing device. The fastener may comprise, for example, a sleeve or a clip. In another embodiment, the module is adapted to facilitate alignment of the first passage and the second passage with, respectively, the entrance aperture and the light source of the mobile computing device.

The optical module may comprise a wall between the first passage and the second passage for shielding the optical train from the light source.

The optical module may be configured to receive, or including, a transparent or near- transparent contact plate or obturator substantially in an image plane defined by the front face and for forming contact with the specimen.

In another embodiment, the optical module comprises an identification indicium imagable by the camera of the mobile computing device. The identification indicium may be configured to provide user or module identification (such as to enable module specific application software), and/or to provide spatial and/or spectral calibration of the images created by the module.

In one embodiment, the optical module comprises a cross polarising

system comprising a first polariser for polarising illumination light from the light source located optically before the front face, and a second polariser cross polarised relative to the first polariser located optically between the front face and the optical train.

In another embodiment, the optical module comprises a light guide adapted to guide illumination light from the light source to the front face and/or homogenise the illumination light from the light source. For example, the light guide may comprise fibre-optic, light tube, lens, annular diffusing element and/or faceted light guide elements. In an embodiment, the optical train comprises an aspheric imaging lens system. The aspheric imaging lens system may be configured to image a flat field specimen without distortion and provide a magnified image that can be refocused by the camera of the mobile computing device. The aspheric imaging lens system may be configured to produce a beam coincident with the entrance aperture of the mobile computing device.

The optical module may be configured for use in conjunction with the mobile computing device as a dermatoscope, an otoscope, a microscope, an ENT (Ear/Nose/Throat) scope, or a borescope. The optical module may further comprise a speculum attachment. In various embodiments, the speculum attachment:

i) is detachably attachable to the optical module;

ii) is disposable;

iii) configures the optical module for use as an otoscope; and/or

iv) includes separate light paths for illumination light and return light.

In one embodiment, the optical module further comprises a uniform illumination mechanism. This may entail employing an interior volume of the module as the second passage, the second passage having an exit that at least partially surrounds the entrance of the first passage at the front face. According to this aspect, there is also provided such a speculum attachment. Thus, the invention also provides a speculum attachment configured for use with an optical module of this broad aspect, wherein the speculum attachment is:

i) detachably attachable to the optical module;

ii) configures the optical module for use as an otoscope; and

iii) includes separate light paths for illumination light and return light.

The speculum attachment may be disposable. According to a second broad aspect of the invention, there is provided a mobile computing device (such as a mobile telephone or tablet computer) comprising an optical module according to the first broad aspect.

The mobile computing device may further comprise analysis software executable by the mobile computing device and adapted to analyse images collected with the optical module.

According to a third broad aspect of the invention, there is provided an imaging apparatus, comprising:

a mobile telephone or other mobile computing device; and

an optical module according to the first broad aspect.

According to a fourth broad aspect of the invention, there is provided an imagining apparatus, comprising:

a camera;

a light source located adjacent to the camera;

a housing located over the camera and the light source and having a front face for directing towards or locating against a specimen, the housing defining a first passage for conducting light from the light source and traversing the first passage to illuminate the specimen and a second passage for conducting return light from the specimen and traversing the second passage to the camera; and

wherein the first passage and the second passage are substantially coincident or concentric at the front face. In an embodiment, the imagining device further comprises an optical train located in the second passage and configured to form an image of the specimen that is imagable by the camera of the mobile computing device, wherein the camera is configured to image the image formed by the optical train. ln the third and fourth aspects of the invention, the imaging apparatus may be, for example, a dermatoscope, an otoscope, a microscope, an ENT (Ear/Nose/Throat) scope, or a borescope. The imaging apparatus may further comprise analysis software executable by the imaging apparatus and adapted to analyse images collected with the imaging apparatus.

It should be noted that any of the various individual features of each of the above aspects of the invention, and any of the various individual features of the embodiments described herein including in the claims, can be combined as suitable and desired.

Brief Description of the Drawing

In order that the invention may be more clearly ascertained, embodiments will now be described, by way of example, with reference to the accompanying drawing, in which:

Figure 1 is a schematic front view of a dermatoscope module according to an embodiment of the present invention;

Figure 2 is schematic front perspective view of the dermatoscope module of figure 1 according to an embodiment of the present invention;

Figure 3 is a schematic rear perspective view of the dermatoscope module of figure 1 according to an embodiment of the present invention;

Figures 4A to 4C are schematic front, side and rear views of the dermatoscope module of figure 1 attached to a mobile telephone;

Figure 5 is a schematic cross-sectional view of the dermatoscope module of figure 1 according to an embodiment of the present invention;

Figure 6 is a schematic cross-sectional view of a dermatoscope module according to another embodiment of the present invention;

Figure 7 is a schematic perspective of a dermatoscope module according to another embodiment of the present invention;

Figure 8 is a schematic perspective view of a dermatoscope module according to another embodiment of the present invention;

Figures 9A to 9C are schematic perspective views of the dermatoscope module of figure 8 attached to a mobile telephone;

Figure 10 is a schematic view of an otoscope attachment to accommodate a disposable speculum according to an embodiment of the present invention, attached to a base module according to an embodiment of the present invention;

Figures 1 1A and 1 1 B are schematic views of the optical stalk of figure 10;

Figure 12 is a schematic view, comparable to that of figure 1 1 , of an otoscope speculum attachment, disposable specula and optical stalk according to another embodiment of the present invention, attached to a base module according to an embodiment of the present invention;

Figure 13 is a schematic front perspective view of a dermatoscope module according to an embodiment of the present invention;

Figure 14 is a schematic rear perspective view of the dermatoscope module of figure 13;

Figure 15 is a further view of the dermatoscope module of figure 13;

Figure 16 is a further view of the dermatoscope module of figure 13;

Figures 17A and 17B are views of variations of the dermatoscope module of figure 13, with differently sized 45-degree planar mirror; and

Figure 18 is a further view of the dermatoscope module of figure 13.

Detailed Description

Figures 1 and 2 are, respectively, a schematic front view and a schematic front perspective view of an optical module in the form of a dermatoscope module 10 according to an embodiment of the present invention. Dermatoscope module 10 is adapted to be used as an accessory of— and attached to— a mobile computing device (such as a mobile telephone or tablet computer) equipped with a camera having an entrance aperture and built-in light source, the latter being typically in the form of a flash generally comprising a LED. These front views thus show the face of dermatoscope module 10 that, in use, is placed in contact with or directed towards the skin or other specimen to be imaged. The rear face (not shown in figures 1 and 2) faces the mobile computing device. Dermatoscope module 10 includes a generally solid main body 12 of a plastics and/or metallic material, with a generally cylindrical recess 14 in its front face 16 (which defines an image plane). A plastics material is preferred, because metallic materials may interfere with antenna systems in mobile devices— especially as antenna systems are often located near the camera. In embodiments, however, in which images are stored for subsequent transmission or uploading, this concern may not arise as the module 10 may be removed from the mobile devices during that transmission or uploading.

Body 12 defines, at the base of recess 14, an aperture 18 that passes through body 10 to its rear face (see figure 3), and which contains and supports an optical train 20 of dermatoscope module 10. Recess 14 and aperture 18 together provide a passage or path for return light from the specimen to the entrance aperture of the camera of the mobile computing device. Body 12 also defines an illumination passage 22 from an entrance (see figure 3) in the rear face of body 12 to an exit 24 in recess 14. Aperture 18 is generally cylindrical with its axis perpendicular to front face 16 (and indeed to the rear face) of body 12, while illumination passage 22 runs obliquely from front face 16 to the rear face of body 12 such that exit 24 is displaced to be left of the entrance (as seen in the view of figure 1).

Dermatoscope module 10 also includes a fastener (not shown: see figures 4A to 4C) adapted to attach body 12 to the mobile computing device suitably aligned with the entrance aperture of the camera and the flash of the mobile computing device.

Optical train 20 is in the form of, in this embodiment, an aspheric lens system, adapted to form a magnified image of the skin or other specimen to the camera of the mobile computing device to which dermatoscope module 10 is attached. The image formed by the aspheric lens system is desirably as aberration free and as non-vignetted as possible. It will be appreciated that optical train 20 can be configured as desired, including being tailored according to the optical characteristics of the intended mobile computing device. Generally, however, optical train 20 is configured to form an image on the assumption that i) the specimen is in the same plane as front face 16 of solid body 12 and ii) the entrance aperture of the camera of the mobile computing device is focussed at infinity. The latter assumption is based on the fact that the entrance aperture of the cameras of mobile computing devices— being generally constrained in their geometry, ability to adjust focus, etc.— function optimally when focussed at infinity. Indeed, some mobile computing devices have fixed camera lens systems and can focus, in effect, only at infinity.

Figure 3 is a schematic rear perspective view of dermatoscope module 10. As may be seen in this figure, entrance 26 of illumination passage 22 is generally square and located in the rear face 28 left (in this view) of the exit 30 of aperture 18. Dermatoscope module 10 is adapted to be mounted on a mobile computing device

(and in particular a mobile telephone) such that the exit 30 of aperture 18 and hence of optical train 20 is located over the entrance aperture of the camera of the mobile computing device, and such that entrance 26 of illumination passage 22 is located over the flash of the mobile computing device. That is, exit 30 of aperture 18 and entrance 26 of illumination passage 22 are displaced from one another by approximately the distance between the entrance aperture of the camera and the flash of the intended mobile computing device. The dimensions of dermatoscope module 10 are thus selected to fit the intended mobile computing device— though it should be noted that the size of exit 30 of aperture 18 and entrance 26 of illumination passage 22 will generally be larger than the entrance aperture of the camera and the flash, respectively, and hence sufficiently large to accommodate a variety of different camera to flash distances and hence a variety of mobile computing devices.

As is also apparent from this figure, exit 30 of aperture 18 and entrance 26 of illumination passage 22 separated by a portion 32 of rear face 28 of body 12, and body 12 also includes a lateral wall 34 extending forwardly from portion 32. Portion 32 and, in particular, lateral wall 34 serve to shielding the light path between optical train 20 and the entrance aperture of the camera of the mobile computing device from stray light from the flash of the mobile computing device.

Figures 4A to 4C are schematic front, side and rear views of dermatoscope module 10 attached to a mobile computing device in the form of, in this example, a mobile telephone 40. Referring to figure 4A, in use, dermatoscope module 10 is removably attached generally to the rear 42 of mobile telephone 40, with optical train 20 optically aligned with and located over the entrance aperture of the camera (not shown) of mobile telephone 40 and with entrance 26 of illumination passage 22 located over the flash 44 of mobile telephone 40.

Referring to figures 4B and 4C, dermatoscope module 10 includes a fastener 46 for holding dermatoscope module 10 in place on the mobile computing device (viz. mobile telephone 40). In this embodiment, fastener 46 is in the form of a hood that extends rearwardly from body 12 of dermatoscope module 10 (and may be integral therewith), with a top wall 48, a side wall 50 and a rear wall 52 that are adapted to define, together with rear face 28 of dermatoscope module 10, a sleeve for receiving a portion of the mobile computing device. Thus, in use top wall 48, side wall 50 and rear wall 52 extend over the top edge 54 of mobile telephone 40, beside a side edge 56 of mobile telephone 40 and over a portion of the front face 58 of mobile telephone 40. Rear wall 52 of fastener 46 is shaped so as not to cover the speaker grill 60 or screen 62 of mobile telephone 40.

Fastener 46 is of a resilient plastics material. This is due to the requirement for positive alignment of camera of the mobile computing device to the optical axis of optical train 20 of dermatoscope module 10. This alignment may be facilitated by the provision of a ramp guide into a detent cavity sized to align the mobile computing device bezel accurately to the optical axis and pupil of optical train 20. Fastener 46 is sized, and the plastics material selected, so that a secure but detachable friction fit with the mobile computing device can be formed. As will be appreciated, however, fastener 46 may assume many forms, such as a metal or plastic clip for holding body 12 to the mobile computing device by spring force, or an adhesive on rear face 28 of body 12 (the adhesive selected to allow dermatoscope module 10 to be detached).

Dermatoscope module 10 may include a uniform illumination mechanism (not shown) for guiding and/or homogenising light from the flash of the mobile computing device to the imaging plane (typically skin), to facilitate uniform illumination of the focal plane from the flash, being a displaced light source. The uniform illumination mechanism may comprise, for example, fibre-optics, light tubes, lenses, diffusers, reflectors and/or faceted optical constructions. Further, dermatoscope module 10 optionally includes a cross-polarising system (not shown) for minimizing the collection of specular reflection from the surface of the specimen. Such reflection is generally undesirable, as it tends to contaminate the image. The cross-polarising system may comprise mutually crossed first and second polarisers. The first polariser may effect linear or circular polarisation of light from the flash. For example, the first polariser may be in the form of a polarising filter located in illumination passage 22 (though generally not as a polarising window in the plane of rear face 28, in case the flash is raised above rear face 42 of the mobile telephone or other mobile computing device); in embodiments that include a uniform illumination mechanism, the uniform illumination mechanism may also constitute the first polariser. The second polariser— located optically after the first polariser— may be in the form of, for example, a polarising filter located in or just rearward of the plane of front face 16 of body 12. Such a second polariser may be located, for example, at exit 24 of illumination passage 22. In addition, dermatoscope module 10 may include a thin, transparent (or near transparent) contact plate or obturator essentially in the plane of the front face 16 of body 12 and typically closing recess 14. Referring to figure 2, it will be noted that circular recess 14 in front face 16 includes a step or shoulder 15 at its forward end adapted to support such a contact plate. In use, the contact plate serves two functions: i) it may ensure that the specimen, once pressed dermatoscope module 10, lies uniformly in the focal plane defined by front face 16, and ii) it may support a thin layer of liquid or viscous medium, if such a medium is applied to the specimen or front face 16, such as facilitate light transfer. The contact plate may also constitute the second polariser. Indeed, the contact plate— though generally transparent— may be in the form of an optical filter should it be desired to filter the illumination light from the flash and/or the return light from the specimen. Furthermore, the contact plate may be removable so that, for example, it can be swapped for another contact plate of different characteristics, whether of polarisation, filtering or otherwise. Alternatively, contact plate may also constitute the second polariser. The contact plate may bear an identifier or authenticator, such as an indicium inscribed (such as by laser etching) or otherwise borne by the contact plate, to enabling subsequent identification, verification or authentication of the dermatoscope module 10 or of an image taken thereby. Such an identifier or authenticator would be indicative of dermatoscope module 10 and/or the contact plate, and be desirably located at the specimen-side of the contact plate and hence in the plane to be imaged by dermatoscope module 10. It may also be used to facilitate the spatial calibration of images and, optionally, of the colour calibration of images.

The identifier or authenticator of this embodiment is a unique laser etched code inscribed into the specimen-side of the contact plate, to provide security, by verifying that any images made with dermatoscope module 10 were obtained with

dermatoscope module 10.

In certain embodiments, dermatoscope module 10 includes an optical filter, located in recess 14 between optical train 20 and front face 16. Such an optical filter may be placed, for example, over aperture 18 so that it intersects return light from the specimen but not illumination light exiting illumination passage 22, or behind— or in place of— a contact plate, if it is desired or acceptable to have the optical filter intersect both illumination light and return light.

Figure 5 is a schematic cross-sectional view 70 of dermatoscope module 10.

Figure 6 is a schematic cross-sectional view of a dermatoscope module 100 according to another embodiment of the present invention, seen generally from above, together with a portion of a mobile telephone 140 (having a camera 143 and flash 144) to which dermatoscope module 100 is removably attached. Dermatoscope module 100 includes a solid main body 1 12 with a front face 1 16 (which defines an image plane) and a rear face 128, and having a generally cylindrical recess 1 14 and an aperture 1 18 that— together— provide a path for return light from an illuminated specimen located adjacent to front face 1 16 to camera 143 of mobile telephone 140. Dermatoscope module 100 also includes an illumination passage 122 that provides a path for illumination light from flash 144 of mobile telephone 140 to the specimen.

Dermatoscope module 100 includes an optical train (now shown) located in aperture 1 18.

Dermatoscope module 100 further includes a fastener 146 that extends rearwardly from body 1 12 and is of a resilient plastics material. Fastener 146, with rear face 128, constitutes a sleeve that accommodates mobile telephone 140. Camera 143 of mobile telephone 140 extends from the main body of mobile telephone 140, so rear face 128 of body 1 12 of dermatoscope module 100 includes a rebate or slot (not shown) for accommodating and guiding camera 143 as mobile telephone 140 is received by fastener 146. This rebate or slot may be oriented in any convenient manner, but is advantageously either parallel to the top or side edge of mobile telephone 140.

Circular recess 14 includes a step or shoulder 1 15 for accommodating a contact plate or obturator (not shown) essentially in the plane of front face 1 16. In addition, dermatoscope module 100 also includes an optical filter 1 17 located in a cavity 1 19 provided at the forward end of aperture 1 18.

Dermatoscope module 100 may also include a cross-polarising system and a uniform illumination mechanism (not shown) comparable to those described above in the context of dermatoscope module 100 of figure 1 .

Figure 7 is a schematic perspective of a dermatoscope module 160 according to another embodiment of the present invention (with fastener omitted), with a main body 162 having a front face 164 (defining an image plane) and a rear face 166, and defining a generally cylindrical recess 168 and an aperture 170 that— together— provide a path for return light from an illuminated specimen located adjacent to front face 164 to a camera of a mobile computing device. Dermatoscope module 160 also includes an illumination passage 172 that provides a path for illumination light from a flash of a mobile computing device to a specimen.

Dermatoscope module 160 includes an optical train (now shown) located in aperture 170, and may include other optional features in the same manner as dermatoscope module 10 of figure 1 . Dermatoscope module 160 is thus functionally similar to dermatoscope module 100 of figure 6. Figure 8 is a schematic perspective of a dermatoscope module 180 according to another embodiment of the present invention, with a main body 182 having a front face 184 (defining an image plane) and a rear face 186, and defining a generally cylindrical recess 188 and an aperture 190 that— together— provide a path for return light from an illuminated specimen located adjacent to front face 182 to a camera of a mobile computing device. Dermatoscope module 180 also includes an illumination passage 192 that provides a path for illumination light from a flash of a mobile computing device to a specimen.

Dermatoscope module 180 includes a fastener 194 of a resilient plastics material for engaging a mobile computing device. A rebate or slot 196 (containing a ramp on the upper surface) is provided in the leading edge of rear face 186 for accommodating a portion of a camera of a mobile computing device, to guide the phone bezel into a detent cavity accurately sized to facilitate the locating of aperture 190 over the camera. If the intended mobile computing device does not have a bezel, one can be provided and adhered to the phone permanently without affecting the operation of the camera of the mobile computing device or the use of a protective case.

Dermatoscope module 180 includes an optical train (now shown) located in aperture 190, and may include other optional features in the same manner as dermatoscope module 10 of figure 1 .

Figures 9A to 9C are schematic perspective views of dermatoscope module 180 of figure 8, shown attached to a mobile telephone 200. As is apparent in figure 9A, fastener 194 engages front face 202, top edge 204 and right edge 206 of mobile telephone 200. As is apparent in figures 9B and 9C, dermatoscope module 180 includes an optical train 210 in aperture 188 and, in use, main body 182 extends from rear face 212 of mobile telephone 200.

The embodiments described above by reference to the figures relate to dermatoscopes, but it will be appreciated that other embodiments may be adapted for use as an otoscope, a microscope, an ENT (Ear/Nose/Throat) scope, a borescope or otherwise, to provide— in conjunction with a mobile computing device— a handheld illuminated imaging system. For example, a basic imaging module, such as any of dermatoscope modules 100, 160 and 180 of figures 6, 7 and 8 respectively, may be provided with an otoscope speculum The otoscope speculum may be provided as an attachment (which may optionally be disposable), or be integrally formed such that the dermatoscope module is in fact an otoscope module. Thus, figure 10 is a schematic view of a disposable otoscope speculum attachment 220, for use in ENT examination, attached to a base module 222. Base module 222, in this embodiment, is comparable to dermatoscope module 100 of figure 6. In some examples base module 222 may be configured to function as such a dermatoscope module, bit in other examples the optics of base module 222 are specifically configured for use with additional optical elements, as are described below.

Speculum attachment 220 is detachably attachable to base module 222. This is effected by providing speculum attachment 220 and base module 222 with

complementary circular engagement surfaces that facilitate a clip-on fit. Speculum attachment 220 is of generally frusto-conical form 224, with a generally cylindrical axial passage 226 and an illumination stalk 228 located in central axial 226 for passing light to and from the specimen (e.g. ear). When speculum attachment 220 is engaged with base module 222, dermatoscope module 220 is located over the front face of base module 222 (cf. front face 1 16 of dermatoscope module 100), with central passage 226 aligned in parallel with the optical axis of base module 222, so that— in use— central passage 226 is aligned with the camera of the mobile computing device (such as a mobile telephone) to which base module 222 is attached.

Conventional otoscopes provide illumination of the target outer ear channel by diverting light from a source down the inside of the speculum and viewing the illuminated image down the same path. Speculum attachment 220, as illustrated in figure 10, may also transmitted light from the light source of the mobile computing device to the specimen, along central passage 226 in this manner also. This can be facilitated by providing base module 222 with light guides or the like (as discussed above) so that light from the light source of the mobile computing device is directed along central passage 226 more closely parallel to central passage 226 than it would be if it were transmitted from the light source, along the illumination passage 230 of base module 222 and into central passage 226 without such guidance. Indeed, the transmission of the illumination light parallel to central passage 226 may be further facilitated by providing, according to this embodiment, speculum attachment 220 with illumination stalk 228. Referring to figure 1 1 A, illumination stalk 228 comprises an outer annular tube 232 to act as a light path for transmitting illumination light to the specimen (e.g. ear). Outer annular tube 232 may be in the form of a light guide or fibre optic or reflective diffuser element. Illumination stalk 228 also includes a cylindrical central tube 234 to capture return light and to confine the optical image; central tube 234 may include one or more lenses to enhance image transmission. Thus, illumination stalk 228 separates illumination and imaging paths. Stalk 228 may be essentially permanent (being formed integrally or otherwise with speculum attachment 220), may be translatable to correct focus, and may be removable but held within central passage 226 with a friction fit. As may be seen in figure 1 1 A and 1 1 B, outer annular tube 232 of illumination stalk 228 includes a plurality of optical fibres extending the length of and embedded within outer annular tube 232. In this embodiment, there are six such optical fibres, arranged equidistantly around outer annular tube 232. Other numbers of fibre or fibres may be employed. In each case, the optical fibre or fibres collect illumination light from the base 240 of illumination stalk 228 and transit that light to the distal tips 238 of the optical fibres at the distal tip 242 of illumination stalk 228 (and hence of speculum attachment 220).

Alternatively, different forms of light guide or guides may be employed to transmit illumination light from the base 240 of stalk 228 to the distal tip 242 of stalk 228.

Indeed, outer annular tube 232 of stalk 228 may comprise or be composed of a single cylindrical light guide, and other configuration are possible.

The distal tips 238 of the optical fibres (or other light guide or guides) thus provide illumination coaxially to the specimen (ear, etc.). Through this arrangement the specimen illumination emanates from distal tip 242 of speculum attachment 220 independent of the optical imaging path.

Illumination stalk 228 also includes an objective lens 236 coaxially positioned at distal tip 242 of stalk 228, and optionally projecting from that tip (so as not to be obscured by the speculum proper). Objective lens 236 collects (divergent) light from the illuminated specimen, and focusses that light down central tube 234 of illumination stalk 228. The objective lens may be complemented by auxiliary optics positioned further down the imaging path to ensure collimation and aberration correction of the image presented to the smartphone camera. This configuration enhances the field of view by reducing or eliminating the imposed field stop otherwise imposed by the internal diameter of the distal tip 242 of the speculum, which usually defines the field of view of an otoscope. An additional advantage is that, in providing a less obstructed view of the specimen (as an outer ear, nostril or throat), it may be possible to reduce the need to manipulate the speculum to obtain the desired view (such as of the eardrum) or surrounding tissue, which can be painful to the subject. This configuration also permits the use of wide range of distal tip diameters. For example, a tip diameter of 2.5 mm might be employed for infants; a tip diameter of greater than 10 mm might be employed for nose and throat examination or for veterinary use. Hence, in a clinical environment, speculum attachment 220 and/or stalk 228 may be selected according to subject and expected use.

Optionally, the stalk 228 and distal tip 242 can be protected via a disposable thin plastic film to prevent contamination; the stalk 228 may be made of sterilisable material.

Although speculum attachment 220 and stalk 228 are configured to be employed as accessories for a mobile computing device, in alternative embodiments, one or both may be provided in a stand-alone instrument.

Figure 12 is a schematic view, comparable to that of figure 10, of an otoscope speculum attachment 250 according to another embodiment of the present invention, attached to a base dermatoscope module 252 and provided with an optical stalk 254.

Figures 13 and 14 are, respectively, a schematic front perspective view and a schematic rear perspective view of a dermatoscope module 260 according to a further embodiment of the present invention. Dermatoscope module 260 includes a uniform illumination mechanism in the form of a multi-facetted light guide with imbedded or sculpted elliptical frustro-conical mirror deflector and planar mirror, adapted to be attached to a mobile computing device (such as a smart phone) having a camera and a flash (e.g. an LED flash), aligned to accept and divert an input beam from the flash of the mobile computing device.

Dermatoscope module 260 is formed of a clear material (such as a plastics material, e.g. acrylic, PMMA or a polycarbonate material), so that illumination light can be conducted within that material. However, many of the surfaces of dermatoscope module 260 are mirrored (as described below), such as by coating the clear material with a reflective material, so that those surfaces reflect illumination light being conducted internally. The coating may comprise, for example, a suitable metal such as aluminium or chromium or a reflection enhancing multi-layer dielectric film coating.

Thus, dermatoscope module 260 has a mirrored front face 262 that, in use, is typically located adjacent to or directed towards a subject, a mirrored rear face 264 that is configured to be located against the rear of the mobile computing device, and mirrored side faces 266a to 266h. Dermatoscope module 260 has an unmirrored lens tube 270 for housing and supporting an optical train (not shown) of one or more lenses therein. Lens tube may be scaled to provide an absorbing surface around the lens train to minimize unwanted reflections into the imaging field. The lens train is adapted to focus incident light from the subject so as to be imageable by the camera of the mobile computing device. Dermatoscope module 260 also includes an unmirrored annular illumination aperture 272 (from which illumination light from the flash is emitted towards the subject). Referring to figure 14, dermatoscope module 260 includes a mirrored, elliptical frustro-conical reflector 274 and an unmirrored flash entrance 276 of rear face 264, for admitting light emitted by the flash of the mobile computing device.

Dermatoscope module 260 also includes a 45-degree planar mirror (not shown in this figure, but located as indicated by reference numeral 278) for receiving the incoming beam from the flash, and deflecting that beam away from reflector 274 and towards a planar multi-mirror back reflector system.

The back reflector system comprises the internal surfaces of front face 262, rear face 264 and side faces 266a to 266h. The back reflector system can be modularised such that it can be positioned around lens tube 270 to provide a more balanced projected uniform annular light beam via illumination aperture 272, in order to minimize illumination 'hot spots' in the image plane. The resultant projected annular light source is then available for further processing by diffusers or polarising filters prior to illuminating the image plane. The back reflector system surrounds reflector 274 and deflects the illumination beam towards beam towards reflector 274 from multiple sides. Reflector 274 in turn redirects the illumination beam upwards towards illumination aperture 272 surrounding lens tube 270. The elliptical shape of reflector 274, and the positions of the elements of the back reflector system, are selected to make the illumination field projected by illumination aperture 272 as uniform as possible or as desired. Figure 15 is a partially transparent, generally front perspective view of dermatoscope module 260, in which flash entrance 276, lens tube 270 and frustro-conical reflector 274 are shaded. It will be apparent that frustro-conical reflector 274 is indented in the direction of lowest side face 266h; this is to define an aperture 280 through which 45- degree planar mirror 278 initially directs illumination light (towards the interior surface of lowest side face 266h).

Figure 16 is a further, partially transparent generally side view of dermatoscope module 260, in which frustro-conical reflector 274, 45-degree planar mirror 278 and side face 266h are shaded. The internal surface of side face 266h is thus the first element of the back reflector system to which 45-degree planar mirror 278 directs illumination light from the flash.

Figures 17A and 17B are views of variations 260' and 260" of dermatoscope module 260 of figure 13, with differently sized 45-degree planar mirror 278' and 278" respectively. As is apparent from these figures, the 45-degree planar mirror may optionally protrude into the transparent light guide volume (rather than occupy the volume surrounding lens tube 270). Figure 17A illustrates a minimal example of such a variation, while in figure 17B 45-degree planar mirror 278" extends almost as far as front face 262. In such variations, the unmirrored flash entrance 276 is in the form of a curved rectilinear entrance in the rear of frustro-conical reflector 274, that is, an unmirrored region in the rear of frustro-conical reflector 274. The 45-degree planar mirrors 278', 278" constitute dual sided mirrors, and also shade direct illumination of illumination aperture 272, thereby minimizing potential hotspots at this point, and may play the further role of filling-in any shading of the back reflected beam against the frustro-conical reflector 274 behind the 45-degree planar mirror.

Figure 18 is a further, partially transparent generally front perspective view of dermatoscope module 260. In this view, frustro-conical reflector 274 is shaded, and the approximate field of illumination 282 is indicated. As will be especially apparent from this figure, illumination light from the flash and directed by 45-degree planar mirror 278 through aperture 280 to the interior surface of side face 266h is scattered throughout the internal volume of dermatoscope module 260 until reflected by frustro- conical reflector 274 towards rear face 262 and out of illumination aperture 272.

Dermatoscope module 260 may be manufactured using, for example, injection moulding, machined from light guide sheet or fabricated from individual components. It is envisaged that the preferred construction method would entail integrally moulding or casting reflector 274, side faces 266a to 266h, and 45-degree planar mirror 278 into a clear light guide material, followed by the selective mirror coating of those external faces (viz. front face 262, rear face 264 and side faces 266a to 266h) required to be mirrored.

Modifications within the scope of the invention may be readily effected by those skilled in the art. For example, In certain embodiments, such as a microscope module, the front face of the module may include a slide holder for holding a microscopic slide to be examined. Modules according to other embodiments, similarly, include suitable holders for other forms of specimen, or to facilitate the examination of specific forms of specimen. In certain embodiments, such as a microscope module, the front face may be vertically translated by mechanical means to provide for focus changes. This translation may be provided by a flexure device, spacer or fine screw thread encircling and displacing the front face. It is to be understood, therefore, that this invention is not limited to the particular embodiments described by way of example hereinabove.

In the claims that follow and in the preceding description of the invention, except where the context requires otherwise owing to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, that is, to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

Further, any reference herein to prior art is not intended to imply that such prior art forms or formed a part of the common general knowledge in any country.