DE112014004113T5 - Improvements for and regarding medical hand-held devices - Google Patents

Abstract

A medical handset for use in inspecting a structure of the human or animal body comprises an electromagnetic radiation source and projection optics for projecting the electromagnetic radiation from the source onto the structure to be inspected, the projection optics comprising a reflector from which the radiation is radiated during the Is reflected in the direction of the structure, wherein the device comprises viewing means to allow the structure to be viewed, the device comprising a mask arranged to prevent the view or image, or the can be seen by the viewing means, is affected by the electromagnetic radiation from the source that misses the reflector.

Description

Field of the invention

This invention relates to a medical hand-held device for use in inspecting a structure of the human or animal body.

Background of the invention

The invention is particularly applicable to otoscopes and hand ophthalmoscopes, especially direct ophthalmoscopes. There is a tendency for these devices to be frequently used in a variety of locations over the course of a day, which is why these devices are usually worn between the applications on the user's body (for example, in a doctor's shirt pocket). Typically, the handle of such a device includes a shaft which depends from the device head and receives a power supply for a light source which is used to irradiate the portion of a subject's eye or ear to be examined, i. to illuminate. Since the user must be able to control the position and movement of the device very precisely, the handles of such devices are usually designed to be long enough to cover the entire palm of most users while being connected to them Purpose are typically at least 12 inches long. Such handles are long enough to receive an energy source in the form of a pair of serially connected coaxial AA batteries arranged in an abutting relationship. However, it has been found that such devices are difficult to stow in a user's pocket.

Summary of the invention

According to the invention, there is provided a medical hand-held device for use in inspecting a structure of the human or animal body, the device comprising viewing means for use in viewing the structure and a handle enabling a user to hold and use the device , where the handle is not more than 10 cm long.

Contrary to conventional wisdom that the handle should be long enough to go across the palm of a user's hand, it has been found that a device with a shorter handle can still be operated effectively. The shorter handle allows the device to be easily stowed in a bag, and effectively lowers the center of gravity of the device, making it more stable when stowed in a bag or when it is in use.

In fact, the distance between the top of the device and its center of gravity can be shortened by using a shorter handle. Thus, the apparatus preferably includes a pocket-retaining clip which also has a point of contact with the external pad (e.g., the top of a pocket) which is typically 10 to 20 mm higher relative to the head of the device than a conventional device. This can be achieved by using a retaining clasp that extends upwards from its attachment point on the device for that distance before it is bent back on itself at the point of contact. Alternatively, the retaining clip may be attached to the device at a position closer to the top of the device than is the case with a conventional device.

Preferably, the handle is not more than 8 cm long, preferably 7.5 cm plus or minus 1 mm long.

The apparatus preferably comprises irradiation means for irradiating the structure to be inspected with electromagnetic radiation to facilitate the inspection. Thus, for example, the irradiation means may include a light source and projection optics to project light from the source onto the structure to illuminate it.

The projection optics may comprise a reflector from which light from the source is reflected out of the device during use, the device preferably comprising a mask arranged to prevent the sight or image of the structure passing through the device Viewing means is impaired.

The advantages of the mask are discussed below.

The projection optics may include a collimator lens for collimating a beam of electromagnetic radiation from the source and a projection lens in the path of the beam from the collimator lens to the reflector disposed between the projection lens and the reflector.

The invention can potentially be applied to any hand-held medical device, but the device preferably includes a hand-held ophthalmoscope, otoscope, or retinoscope.

Since these devices are usually worn on the body of the person, it is particularly advantageous for them if they can be easily and safely kept in a bag, for example a shirt or jacket pocket.

Preferably, the total length of the device is not more than 13 cm.

Suitably, the device comprises a head from which extends a shaft comprising a handle.

The irradiation means preferably comprises a source of electromagnetic radiation, the handle being adapted to contain a battery means for forming the source of energy for the source of electromagnetic radiation.

In the latter case, the handle is preferably adapted to contain a battery means formed from a single AA battery, the handle comprising contacts spaced apart by a distance corresponding to the length of a single AA battery connect the terminals at each end of such a battery to the source of electromagnetic radiation.

Preferably, the source of electromagnetic radiation comprises an electroluminescent light source, preferably an LED.

In the case of a conventional hand-held ophthalmoscope or otoscope, power to the light source of the device, usually a light bulb, is provided by a pair of series connected AA batteries in the handle of the device. On the other hand, a single-battery device according to the present invention is smaller and lighter than its conventional counterpart, and because of the relative efficiency of an LED light source and the long life of an LED light source (compared to an incandescent lamp), it is also cheaper to operate ,

According to a second aspect of the invention, there is provided a medical handset comprising an otoscope, ophthalmoscope or retinoscope, the apparatus comprising: a light source and a handle for receiving a single AA battery to provide power for the operation of the source; the handle includes contacts for connecting the terminals at the end of the battery to the source, the contacts being spaced apart by a distance equal to the length of such a battery.

Preferably, the source is electroluminescent, preferably an LED.

According to another aspect of the invention, there is provided a medical hand-held device for use in inspecting a structure of the human or animal body, the device comprising an electromagnetic radiation source and projection optics for projecting the electromagnetic radiation from the source onto the structure to be inspected Projection optics comprises a reflector, from which the radiation is reflected during use in the direction of the structure, wherein the device comprises viewing means to allow the structure is viewed, wherein the device comprises a mask, which is arranged to prevent the view or image seen by the viewing means from being affected by the electromagnetic radiation from the source that misses the reflector.

If a device such as By modifying an ophthalmoscope by simply replacing the conventional incandescent source (for example, a filament bulb with tungsten filament) with an LED lamp, this can be detrimental to the quality of the image that can be seen. It has been found that this problem is due to the fact that the LED has a large luminous surface compared to the incandescent lamp. As a result, the light from the extended source is not properly focused on the reflector when the projection optics were originally designed for use with the less-extended source. As a result, light can be projected beyond the reflector and scattered inside the device, which affects the quality of the image to be seen. The mask cuts out this excess light and allows the extended source to be used in a device having projection optics originally designed for an incandescent lamp without the need to alter the projection optics.

The mask could be arranged to block and / or absorb the beams of electromagnetic radiation that missed the projection optics that missed the reflector, but preferably it is located between the reflector and the rest of the projection optics, blocking jets, that could otherwise pass the reflector.

Preferably, the projection optics include a collimator lens for collimating a beam of the electromagnetic radiation from the source and a projection lens in the path of the beam from the collimator lens to the reflector, the mask being disposed between the projection lens and the reflector.

In this way, the mask can be used to block beams of the electromagnetic radiation coming from the projection lens that do not run along axes intersecting the reflector.

Preferably, the reflector comprises a mirror.

The mirror may be angled such that it has opposite upper and lower edges, the mask being arranged so that an edge is substantially coincident with the upper edge of the mirror to block electromagnetic radiation otherwise from the projection lens to an area where the device would go beyond the top of the mirror.

The edge of the mask preferably has a (e.g., linear) shape corresponding to that of the upper edge of the mirror.

Preferably, the device is an ophthalmoscope.

Preferably, the mask is located 2.3 mm from the projection lens and 3.2 mm from the reflector, with the projection lens having a focal length of 16.925 mm.

The mask may be suitably formed by a plate having an opening or notch to allow passage of the electromagnetic radiation from the projection lens to the reflector.

Preferably, the electromagnetic radiation source comprises an electroluminescent light source, preferably an LED.

Brief description of the drawings

The invention will now be described by way of example only with reference to the accompanying drawings, in which:

1 is a side elevational view of an embodiment of an ophthalmoscope according to the invention;

2 is a partially broken isometric view of the ophthalmoscope with a battery;

3 a partially broken isometric view of the ophthalmoscope (without battery) from the side, which is the view of 2 is opposite;

4 is an exploded isometric view of the handle assembly of the ophthalmoscope;

5 an isometric, broken away view of some components, including a switching mechanism, the handle assembly is;

6 a more detailed view of part of the switching mechanism;

7 is an exploded isometric view of the head assembly of the ophthalmoscope;

8th an isometric view of the head with the front cover removed in an enlarged scale;

9 is a sectional side view of the head showing the spaces between the various elements in the path of the light through the head;

10 another sectional side view of the head is showing parts of the path of a light beam passing therethrough;

11 an isometric view of a holder for an LED module of the ophthalmoscope is;

12 and 12A and 12B show an isometric view, an elevation or an exploded isometric view of the LED module;

13 Fig. 12 is a circuit diagram of the power supply circuits used in the ophthalmoscope; and

14 a side view of an also according to the invention otoscope is; and

15 is an exploded isometric view of the head assembly of the otoscope.

Precise description

This in 1 The ophthalmoscope shown comprises a generally cylindrical handle 1 in which a connector 42 is held with an internal thread through which an ophthalmoscope head 4 on the handle 1 is screwed. The device is a direct ophthalmoscope, with the head 4 in many respects, is the same as a conventional ophthalmoscope head of the type used in the present invention's KEELER JAZZ ^™ ophthalmoscope. The head thus comprises an upper arcuate forehead rest 6 for the user, a viewing port 8th through which the user views an examined eye, a thumbwheel 10 , which is used to select one of a number of different lenses with different magnifications, through which the examined eye through the opening 8th is looked at. A window 12 provides an indication that the selected lens (ie the one on the opening 8th aligned lens).

An annular recess having a circumferential groove 14 immediately under the collar 2 includes, takes a fastener in the form of a ring on, itself part of a pocket-clasp 16 is, whereby the groove and the ring thus serve, the retaining clip 16 on the handle 1 to fix. As in 1 can be seen, the retaining clasp extends 16 from the ring up and is at the turning point 17 , from which the retaining clip 16 down to its distal end 19 extends, bent back on itself. The turning point 17 forms the suspension point (or point of contact) at which the device can be hung in a user's pocket when not in use. The vertical distance between the ring 14 and the turning point 17 is 10 up to 20 mm. The front of the case 1 is with a slide switch 18 to activate and deactivate a light source in the form of a white LED 20 provided in the head. This is a difference between the head 4 and a conventional head because the latter would have a xenon light source.

The handle 1 is slightly tapered from top to bottom and has (at its collar end) a maximum diameter of 22 mm. The height of the handle 1 is 75 mm, while the total height of the device is 129.75 mm.

The handle assembly is in an exploded shape in 4 to see in which is evident that the handle 1 is hollow and has a generally L-shaped copper strip 200 receives, the foot of an electrically conductive coil spring 24 wearing, by suitable means, for example by riveting, on the strip 200 is attached. A copper strip leading to a part-circular collar 202 Shaped is at the top of the strip 200 attached. The stripe 200 is engaged with a contact strip 204 that with the switch 18 interacts relative to the strip 200 to slide to activate and deactivate the LED in the ophthalmoscope head in the manner described below. An insulating ring 206 is in the collar 202 fitted and includes an upper section 208 having a larger diameter to define an annular, downwardly facing shoulder on which the ring 206 on the collar 202 sitting. An electrically conductive metallic connection ring is seated on an upwardly facing annular shoulder passing through the larger diameter section 208 of the ring 206 is defined. One with 210 designated recess in the side of the connector 42 can the contact 204 record when the switch 18 closed is.

As in 4 and 5 can be seen, is the connector 42 provided with an internal thread and includes a lower portion of larger diameter (in which the recess 210 is formed) and an upper portion of smaller diameter, over which an end cap 212 sitting with external thread. The threaded portion of the cap 212 removably engages a corresponding threaded portion on the top of the interior of the handle 1 one to the cap 212 in their place on the handle 1 to keep. At the top of the cap 212 There is an inwardly facing annular lip which is at the top of the fitting 42 abuts the fitting 42 and the section 208 of the ring 206 sandwiched between the top of the cap 212 and the collar 202 to keep these components together with the spring 24 and the strip 200 under control 1 to keep. With 214 ( 5 ) designated inwardly facing lip of the cap 212 leads to an annular, radially outwardly directed flange 216 at the end of the cap 212 , The underside of the flange 216 when the cap is in place on the handle, from the top of the handle 1 spaced, leaving the top of the handle 1 and the bottom of the flange 216 the annular circumferential groove 14 define. The releasable connection between the handle assembly, its components in 4 are shown, and the head 4 is due to the engagement of the thread in the fitting 42 with a corresponding threaded portion 218 (please refer 7 and 8th ) at the bottom of an LED module holder 38 achieved.

The LED holder has an outwardly facing radial flange 220 on, just above the threaded section 218 is arranged and in use during use in a radial inner lip 222 at the base of a head lock ring 2 intervenes.

The holder 38 also contains an LED module 224 (which will be described in more detail below) and has two opposite longitudinal holes 226 and 228 ( 11 ), in which lugs on the inside of a front cover 230 and a rear cover 232 Of the head 4 extend. In 7 is the approach to the rear cover 232 With 234 shown. A condenser lens 58 is in a bracket 248 at the top of the holder 38 held and acts as a collimator lens for that of the LED 20 emitted light.

The front and rear covers abut each other when the device is assembled to define a housing containing various other components of the head, including a frame 236 , If the covers 230 and 232 are arranged so are also two semi-cylindrical end portions 238 and 240 to each other to form a cylindrical, end-to-end threaded fitting onto which the locking ring 2 is screwed. When the locking ring 2 is screwed onto the connector, presses the lip 222 against the flange 220 to the holder 38 to hold in the housing in a position in which the lugs in the cover sections in the longitudinal holes 226 and 228 in extend to the angular position of the holder 38 to ensure. The axial position of the holder 38 is due to the interaction between the flange 220 and the lip 222 as well as the top of the holder 38 as part of 236 guaranteed.

According to the 12 and 12A and 12B the LED module is generally cylindrical and carries at its upper end the LED light source 20 , The module 224 includes a housing 225 made of nickel plated brass cz121. On both sides of the LED 20 is a pair of resilient, outwardly spread arms 244 provided that a press fit for the module 224 in the holder 38 provide. The poor 244 are part of a cap 235 , which is also made of nickel-plated brass cz121 and into the housing 225 screwed to the contents of the module 224 withhold. The bottom of the case 225 comprises an integrally formed sleeve 246 through which there is a conductive staff 30 made of brass ( 2 and 3 ), wherein the lower end of the rod 30 a contact 26 forms to make electrical contact with the positive terminal of a single AA battery in the handle 1 is included. An insulating element 227 made of black acetal has a sleeve 229 on, starting from a cap 231 extends the element. The sleeve 229 gets over the bar 26 pushed to the bar 26 from the sleeve 246 to separate and electrically isolate. The bar is with the connection 46 ( 13 ) of a power converter 36 Connected to the power of the AA battery in a suitable form to operate the LED 20 transforms.

The spiral spring 24 is at the base of the handle 1 arranged and acts as a contact for the negative terminal of the battery, while the contact 26 from the spring 24 spaced at a distance equal to, but slightly smaller than, the length of a single AA battery. So if a battery, such as the battery 22 in 2 , under control 1 is housed, she is between the spring 24 and the contact 26 pressed together. When the switch 18 is closed, the contact acts 204 as a bridge over the insulating ring 206 and thus creates over the strip 200 an electrical connection between the negative terminal of the battery and a ground terminal passing through the terminal 42 of the power converter 36 is formed. When the switch 18 open, the end of the contact rests 204 that is not engaged with the strip 200 located on the insulating ring 206 ,

According to 13 includes the power converter 36 a synchronous Boost WLED driver with 1.1 A and 1 MHz, in this case the integrated circuit 48 MP3412 from Monolithic Power Systems. The grounding input of the integrated circuit 48 is with the connection 42 and thus with the negative terminal of the battery 22 connected when the switch 18 closed (around the strip 40 in contact with the connection 42 to keep). The integrated circuit 48 also has a feedback input (FB) in an error amplifier, which is also connected to the port 42 and with the anode of the LED 20 connected is. The connection of the connection 42 with the FB input via a 7.5 Ω resistor 50 , The output of the RC element (OUT) is connected to the cathode of the LED, and a 10 uF capacitor 52 is about the LED 20 and the resistance 50 connected.

The connection 46 that with the positive connection of the battery 22 is connected, constantly supplies a positive voltage input to the battery supply input (IN) of the integrated circuit 48 and also in an activated control input (EN) of this circuit. The integrated circuit 48 includes an internal NMOS switch and a synchronous switch whose output is in turn connected to the output SW of the integrated circuit 48 connected is. This output is in turn in series with a 4.7 μH inductor 54 whose other side is connected to the connector 46 and the input IN is connected. As in 13 You can see this side of the inductor 54 , the input IN and the connection 46 through a 4.7 μF capacitor 56 also connected to the earth.

The power converter 36 uses a known current switching method to induce in inductor L a voltage higher than the input voltage (ie, the voltage between the terminals) 42 and 46 ). This particular device uses a switching frequency of 1 MHz and stores the boosted voltage in ceramic capacitors that are part of the integrated circuit and then provides a voltage output that is higher than the voltage input. The converter converts the voltage of the AA battery, typically 0.8V to 1.6V, into the voltage needed to drive the white LED 20 to power, typically 2.5V to 5V.

When it is in position in the head, the condenser lens is located 58 in coincidence with an opening 250 in a lower rib 252 of the frame 236 , This lower rib is from an intermediate rib 254 as part of 236 spaced and parallel to it, to accommodate a known type of grid and filter wheel assembly 256 to be defined, which rotatably on a ball-bushing-like spindle 258 mounted in generally U-shaped depressions in the edges of the ribs 250 and 254 is recorded. The grid wheel assembly has a knurled outer surface, part of which is through an opening 257 in the front cover 230 extends to allow the user the wheel assembly 256 to rotate to a selected filter or a selected one Grid in line with the lens 58 bring to. A spring-loaded lock arrangement 259 includes a ball bearing that can be forced into any of a number of corners, the wells (for example 26 in 8th ) to provide a barrier effect. A projection lens 60 is in a position above the arrangement 256 and in coincidence with the lens 58 also in the frame 236 assembled. The projection lens 60 directs light onto an angle mirror 62 that is directly above the lens 60 in the frame 236 is mounted.

The mirror 62 is immediately behind a lighting and viewing opening 64 in the front cover 230 arranged, with this opening on a viewing port 8th in the back cover 232 is aligned. The size and position of the openings 64 and 8th and the mirror 62 are such that the mirror 62 the opening 8th not locked, leaving the user (over the top of the mirror 62 ) through the opening 64 able to see.

A mask 61 is in a position between the projection lens 60 and the mirror 62 at the frame 236 assembled. As this clearer in 8th can be seen, assigns the mask 61 the shape of a plate, which by suitable means in two side grooves, one of which with 63 is shown in the frame 236 is held. The mask 61 is between the lens 60 and the mirror 62 arranged and includes a generally U-shaped longitudinal hole 65 that defines an opening through which the of the projection lens 60 coming light the mirror 62 can reach. The mirror 62 is angled so that it reflects light out of the front of the device and therefore has an upper edge 67 on. This upper edge is in coincidence with a corresponding edge 69 the mask 61 , The mask 61 is therefore arranged such that the portion of the mask between the edge 69 and the outer periphery of the mask 61 the light prevents it from the lens 60 over the top edge 67 of the mirror 62 To get out and then scattered from the inside of the housing and thus disturb the user to see the image.

A wheel body 66 is rotatably mounted around a horizontal axis on the rear cover 32 and carries a series of lenses through which the user can view the examined eye.

All lenses are at the same radial distance from the center of the wheel center 66 and arranged at equiangular intervals around the wheel body. In addition, the wheel surface also carries marks, each of which indicates the thickness of a respective lens and is arranged diametrically opposite this lens. The markings are thus also equiangularly around the wheel center 66 but arranged at a lesser radial distance from the center of the disk. The radial distance of the opening 8th from the center of the disc corresponds to that of the lenses, while the radial distance of the window 12 that is in the back cover 232 is located, that of the markers, so that the mark, at any time in the window 12 is visible, indicating the thickness of the lens at that time in coincidence with the opening 8th located. It will be understood that the openings 8th and 64 and the wheel center 66 include the viewing means of the device. The wheel body 66 has a knurled peripheral surface 10 on, passing through the approximately opposite openings 260 . 262 in the back cover 232 protruding to allow the user to select a desired lens by means of which the person's eye through the opening 8th is looked at. The ophthalmoscope head comprises a ball bush (not shown) in which a ball bearing against the knurled surface 10 is pressed to provide a series of locks, each of the orientation of a respective lens in the wheel body 66 with the sight opening 8th correspond.

The reference number 68 in 1 indicates the approximate position of the center of gravity of the device, indicating that the center of gravity is closer to the bottom than the top of the device, making the device more stable than conventional arrangements (which have a handle that is long enough to hold two AA's). Batteries in a row) whose center of gravity is higher up.

During use, this is done by the LED 20 emitted light through the condenser lens 58 and through the selected part of the grid and filter wheel assembly 256 which, depending on the position of the assembly, may cause the light to pass through a grating, a color filter, or through an opening in the wheel assembly which removes the light from the LED 20 unaffected. Then the light goes from the wheel assembly to the projection lens 60 putting the light on the mirror 66 directed. The mirror 66 reflects this incident light through the opening 64 and in an examined eye. The light returning from the eye can pass through the opening 64 over the top of the mirror 66 and through the opening 8th over a selected lens in the wheel center 66 go, allowing the user to examine the eye through the opening 8th can look at. The identity of the selected lens in the wheel center 66 will be in the window 12 displayed.

As in 10 can be seen, the section of the mask prevents 61 between the edge 69 and the outer periphery of the mask, that of the lens 60 coming light on it, over the edge 67 of the mirror 62 to be projected out and thus scattered on the inside of the housing, through the front and rear covers 230 and 232 is defined. The reference number 70 denotes the section of the lens 60 going beam, the reference numeral 71 refers to the portion of the beam from the mask 61 to the lens 62 goes, and the reference number 72 denotes the portion of the jet emerging from the device, that of the mirror 602 was reflected.

The front and back cover 230 and 232 also be using a screw 233 held together, which is inserted into corresponding threaded openings in the upper regions of the covers.

This in 14 The otoscope shown has many common features with the ophthalmoscope 1 to 13 auf, wherein these features with the same reference numerals as in 1 to 10 , increased by 100 be designated. Thus, the otoscope has a handle 101 in which a switch 118 is provided. The handle 101 also carries a bag-holding clasp 116 , The reference number 170 refers to the head of the otoscope, which is identical to the head of the common otoscope KEELER JAZZ ^TM . In the otoscope of 14 There are many components similar to those in the ophthalmoscope 1 to 10 correspond. In particular, everything is in the grip 101 limited space identical to a corresponding component in the same space in the ophthalmoscope in the 1 to 10 , For example, the arrangement of the contacts for the battery are under control 101 , their connection to a power converter and the LED and the way in which they are mounted / housed, identical to the corresponding components in the ophthalmoscope.

According to 15 points the otoscope head 170 a housing constructed in a manner similar to the ophthalmoscope described above. In this way, the housing has a front cover 264 and a back cover 266 on, at their tops by a screw 268 and at their bottoms by a threaded locking ring 270 held together, which engage with corresponding threaded portions 272 and 274 gets to the covers. The ring 270 also contributes to an LED holder 276 to hold in its position, which is essentially the same as the LED holder 38 The ophthalmoscope is, with the exception that it has a widened upper section 278 to (by engaging with corresponding recesses in the covers 264 and 266 ) help in positioning, and that the holder 276 instead of a clip on its upper side a cylindrical connection socket 280 includes a corresponding plug 282 to be absorbed by a fiber optic cone arrangement 284 depends. In addition, the holder includes 276 an opening 286 that with a spring-loaded ball bearing mechanism 288 interacts on the rear cover 266 held during assembly, the angular position for the holder 276 to deliver.

The holder 276 includes an LED module which is the same as the LED module used in the ophthalmoscope and which can be operated to emit light into the optical fibers in the array 284 to be routed out of the front of the device and into an examined ear. The order 284 is also constructed such that the user can see through the arrangement to view illuminated structures of the ear.

Claims (28)

 A medical handset for use in inspecting a structure of the human or animal body, the apparatus comprising an electromagnetic radiation source and projection optics for projecting the electromagnetic radiation from the source onto the structure to be inspected, the projection optics comprising a reflector from which the Radiation is reflected during use towards the structure, the device comprising viewing means to allow the structure to be viewed, the device comprising a mask arranged to prevent the view or image from which is seen by the viewing means, is affected by the electromagnetic radiation from the source that misses the reflector.  The device of claim 1, wherein the mask is disposed in the path of the electromagnetic radiation from the source to the reflector, thereby blocking rays that would otherwise pass through the reflector.  The apparatus of claim 2, wherein the projection optics include a collimator lens for collimating a beam of the electromagnetic radiation from the source and a projection lens in the path of the beam from the collimator lens to the reflector, the mask being disposed between the projection lens and the reflector.  Apparatus according to any one of the preceding claims, wherein the reflector comprises a mirror. The device of claim 4, wherein the mirror is angled to have opposing top and bottom edges, the mask being arranged such that an edge of the mask is substantially in registration with the top edge of the mirror for electromagnetic radiation block that would otherwise go from the projection lens to an area in the device beyond the top edge.  Apparatus according to claim 5, wherein the edge of the mask has a shape corresponding to that of the upper edge of the mirror.  Apparatus according to any one of the preceding claims, wherein the apparatus is an ophthalmoscope.  Apparatus according to claim 3, wherein the mask is located 2.3mm from the projection lens and 3.2mm from the reflector.  Apparatus according to any one of the preceding claims, wherein the mask is formed by a plate having an opening or notch to allow the passage of electromagnetic radiation from the projection lens to the reflector.  A medical hand-held device for use in inspecting a structure of the human or animal body, the device comprising viewing means for use in viewing the structure, and a handle that allows a user to hold and use the device, the handle no longer than 10 cm is long.  Apparatus according to claim 10, wherein the handle is not more than 8 cm long.  The device of claim 11, wherein the handle is 7.5 cm plus or minus 1 mm long.  Apparatus according to claims 10 to 12, wherein the total length of the apparatus is not more than 15 cm.  Apparatus according to any one of claims 10 to 13, wherein the apparatus comprises a head from which extends a shank comprising a handle.  Apparatus according to any one of claims 10 to 14, wherein the apparatus comprises irradiation means for irradiating the structure to be inspected with electromagnetic radiation to facilitate the inspection.  The device of claim 12, wherein the device comprises a hand-held ophthalmoscope, otoscope or retinoscope.  Apparatus according to claim 15 or claim 16, wherein the irradiation means preferably comprises a source of electromagnetic radiation, the handle being adapted to contain battery means for forming the source of energy for the source of electromagnetic radiation.  The apparatus of claim 17, wherein the handle is adapted to contain a battery means formed of a single AA battery, the handle comprising contacts spaced apart a distance equal to the length of a single AA battery to connect the terminals at each end of such a battery to the source of electromagnetic radiation.  Apparatus according to any of claims 15 to 17, wherein the source of electromagnetic radiation comprises an electroluminescent light source, preferably an LED.  A medical handset comprising an otoscope, ophthalmoscope or retinoscope, the apparatus comprising: a light source and a handle for receiving a single AA battery to provide power for the operation of the source, the handle containing contacts around the terminals at the end the battery to be connected to the source, wherein the contacts are spaced apart with a distance corresponding to the length of such a battery.  Apparatus according to any one of the preceding claims, wherein the source is electroluminescent.  The device of claim 21, wherein the source is an LED. Apparatus according to any one of the preceding claims, wherein the apparatus comprises a bag-holding clasp attached to the apparatus and adapted to define a suspension point from which the apparatus is suspended, the suspension point being at a higher level than the suspension bracket Handle is located when the device is hung in this way.  Apparatus according to any one of the preceding claims, wherein the apparatus comprises a pocket-holding clasp attached to the apparatus in a mounting region of the latter and adapted to define a suspension point from which the apparatus is suspended as it passes through the retaining clasp is held in a pocket with the point over the area of attachment of the retaining clip.  The apparatus of claim 24, wherein the retaining clasp extends upwardly from the attachment region a distance of 10 to 20 mm to a point of inflection from which the retaining clasp extends downwardly to its distal end, the point of inflection forming the suspension point of the retaining clasp. Apparatus according to claim 24 or claim 25, wherein the attachment portion is an annular one Recess in the device comprises, wherein said recess receives a fastener, which is itself attached to the retaining clip. Ophthalmoscope, essentially as it relates to the 1 to 10 the accompanying drawings and is shown in these.  Otoscope, substantially as described and illustrated herein with reference to the accompanying drawings.

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