There are numerous situations where it is necessary to provide an optical element in front of a person's eyes. One obvious example is where the optical element is a lens which adjusts the effective focal length of the eye. Other examples involve optical elements which impart some protective functionality. For instance, tinted lenses are used in sunglasses to allow visibility in bright light conditions and to impart UV-screening.

Welding visors/goggles also include a tinted window or lens to avoid eye damage and enable visibility during welding operations. Such applications often involve the repeated removal and re-introduction of the optical element involved depending upon changes in environmental conditions and user need. This will inevitably involve some manual movement of the optical element, typically as part of a larger construction in which the element is housed. As well as being tedious, this can be potentially dangerous where the user does not have one or both hands conveniently free to move the optical element. It would therefore be desirable to provide eyewear that includes an optical element that can be moved in a hands-free manner.

Accordingly, the present invention provides an article of eyewear comprising: a support member ; an optical element which is moveable relative to the support member between a first position in which the optical element is available for use and a second position in which the optical element is not available for use ; and a mechanism capable of moving the optical element between the first and second positions, wherein the mechanism is adapted to be actuated by movement of a facial muscle of a person wearing the article.

It will be appreciated from the foregoing that the article of eyewear of the invention

(hereafter simply"eyewear) is intended to be worn on the head by a user and that movement of the optical element between first and second positions corresponds respectively to movement of the optical element from a position in front of the user's eyes (when the optical device is required) to a position which is not in front of the user's eyes (when the optical device is not required). The crux of the present invention is that the requisite movement of the optical element is achieved by use of mechanism which is triggered by (deliberate) movement of a facial muscle of the user. This allows the optical element to be moved without the need to use one's hands, i. e. in a hands-free mode.

The support element is that portion of the eyewear to which the optical element is attached.

The optical element is moved between first and second positions relative to the support member, and it follows from this that the two are usually joined together by some form of hinge. The position of the support element is usually fixed when the optical device is worn in use. The support element may take a variety of forms depending upon the intended application of the eyewear. This will be discussed in more detail below.

The term"optical element"as used herein is intended to embrace any component having some desired functionality relative to the naked eye. For instance, the optical element may be a lens which enhances the user's vision. Alternatively, the optical element may have a role which is primarily protection of the eye. Thus, the optical element may be a tinted lens or sheet, as typically used in sunglasses or welding visors/goggles. In this particular context the word"lens"will be used even though this component may not actually have the effect of deliberately adjusting the effective focal length of a wearer's eyes (although this is of course possible by design). Optical elements for use in the present invention may be made by the application or adaptation of known techniques, or are commercially available.

The eyewear may include one or more optical elements depending on the field of use. For instance, when the eyewear includes an optical lens, two lenses are used (one per eye). In this case, the two optical elements are usually moved together when the mechanism is actuated. Alternatively, a single optical element may be used extending over both eyes and surrounds. This is likely to be the case where the eye protection is called for in welding,

for instance. Herein the term optical element is intended to embrace all such possibilities.

When the eyewear includes an optical element for each eye, the support member may take the form of a conventional spectacles frame. In this case the optical elements are suitably positioned and attached to the frame, typically via a hinge. A similar arrangement can be used where a single optical element is used extending over both eyes. Alternatively, in this case the support member may take the form of a headband which is sized to fit around a user's head. As a further alternative, the support member may be adapted to be clipped over an existing spectacles frame so that the optical elements can be used in combination with existing spectacles. One practical application of this embodiment would be the provision of tinted lenses over regular spectacles, thereby converting the spectacles to sunglasses. In this case the support member may be clipped over the spectacles frame in accordance with conventional design for clip-on sunglasses.

In accordance with the invention the mechanism which is responsible for movement of the optical element is actuated (triggered) by movement of one or more facial muscles. In practice the mechanism includes some form of trigger which in use is provided close to or in contact with the facial muscle in question and which is responsive to a deliberate movement of that muscle (by way of relaxation or contraction) such that the mechanism is triggered and the optical element moved as and when required. It is preferred to rely on muscles located in the vicinity of the eye since it can be impractical to rely on muscles from the lower face. It is also preferred to rely on muscles which may be controlled in a deliberate fashion to produce muscle movement of sufficient magnitude to trigger the mechanism used for movement of the optical element. By way of example, mention may be made of the major muscles around the top of and/or between the eyes, for example orbicularis occuli (orbital part above the eye), corrugator supercilii and depressor supercilii. Combinations of muscles may be employed. The choice of muscle to activate the mechanism for moving the optical element, and thus the design of the eyewear, may vary provided that the contraction/relaxation of the muscle may be controlled in a deliberate manner and to the extent suitable for adequate operation of the mechanism used in the eyewear of the invention.

In accordance with the invention, actuation of the mechanism by appropriate facial muscle movement causes movement of the optical element. The eyewear can be configured such that the optical element is initially in a position in front of the eye (i. e. in which the element would be in use) so that appropriate muscle movement actuates the mechanism such that the optical element is moved away from the eye. This would be useful for example where the optical element is a tinted lens and the user experiences a dramatic reduction in environmental light. Alternatively, the eyewear may be configured in the opposite sense such that actuation of the mechanism causes the optical element to be moved to a position in front of the eye. These embodiments have the advantage of facilitating movement of the optical element from one position to another in hands-free fashion.

Once the optical element has been released via the mechanism, it is then necessary to return the optical element to its initial position before the mechanism may be used again.

This may be done manually. However, in another embodiment of the invention the eyewear, and in particular, the mechanism thereof is configured such that activation of the mechanism results in a change of position of the optical element, irrespective of its initial position. In this case movement of the optical element from one position to another results in priming of the mechanism to effect the opposite movement when the mechanism is next activated. In this way the optical element may be moved between first and second positions without any manual intervention at all.

Typically, the mechanism used in accordance with the present invention causes the optical element to be rotated around (a hinge provided on) the support member. Between first and second positions the extent of rotation is usually between 90 and 180°. The extent of rotation may need to be constrained depending upon other head gear the user may be wearing. For instance, if the eyewear is intended to be used in conjunction with a peaked cap or helmet, the peak or helmet front may not permit travel of the optical element through 180°. In this case the extent to which the optical elements rotates between first and second positions may be tailored as necessary. It is important however that when not

required the optical element is moved away from the eye so that vision without the optical element is not hindered.

In one particular embodiment the mechanism comprises a hinge, a spring and a trigger mechanism. The hinge allows movement (rotation) of the optical element relative to the support member. The hinge can be secured to the support member and optical element by conventional methods depending upon the materials involved. The spring may be a torsion spring and is responsible for supplying the energy necessary to move the optical element about the hinge rapidly when the mechanism is actuated. In this embodiment one end of the spring is attached to the optical element and the other to the support member. Again, conventional attachment means and methods may be employed. The optical element and/or support member may include a tab or lug to facilitate attachment of the end of the spring. Alternatively, the ends of the torsion spring may be shaped to allow ease of attachment to the support member and/or optical element. For instance, the end (s) of the torsion spring may be L-shaped.

It will be appreciated that rotational movement of the optical element about the hinge from first to second position (or vice versa as the case may be) will create tension in the torsion spring since the ends of the spring are fixed. The trigger mechanism is used to engage the lens and lock it in place (i. e. in the first or second position). The result is that the torsion spring is trying to move the optical element about the hinge in order to achieve a relaxed state, but the trigger mechanism is preventing this. In this set-up, the eyewear is"primed" and ready to be used. When the trigger mechanism is actuated by movement of the appropriate facial muscle, the optical element is released and is free to move under the action of the spring The muscle movement required to activate the trigger is relatively small (the trigger usually travels less than 0.5 mm before the optical element is released). This said the mechanism used should be sufficiently robust and secure to prevent accidental activation.

Desirably, the sensitivity of the mechanism can be adjusted from user to user. This may be achieved by varying the amount of travel required of the trigger before the optical element

is released. The position of the trigger end relative to the facial muscle relied upon for activation may also be varied in this regard.

In this embodiment the torsion spring is usually about 0.25-0. 5 mm, preferably about 0.3 mm, in diameter and about 40-60 mm, preferably 50 mm, long. The dimensions of the spring and its strength (in terms of the torque that can be developed in it) can be varied and chosen depending upon the particular application of the invention. The weight of the optical element and/or the ease with which it may be rotated about the hinge will also be a contributing factors here.

In one embodiment the trigger takes the form of a length of resilient steel wire attached at both ends to the support member or structure to which the support member is attached, such as a spectacles frame. The wire is arranged so that at some point it passes through a control point coincident to a catch which retains the optical element in place against tension in the spring. The wire is also arranged so that movement of it, as a result of contact with the chosen facial muscle (s), causes the catch and thus the optical element to be released.

More specifically, in one embodiment the trigger mechanism consists of a trigger wire and a catch which is adapted to co-operate with a part of the trigger wire in an engagement/disengagement type arrangement. The trigger wire may be formed of any suitable material which allows the wire to be resilient and flexible. Steel wire is a convenient material for the trigger wire. Both ends of the trigger wire are attached to the support member so that the wire forms an arc. This is arranged/positioned such that movement of the relevant facial muscle will cause the shape of the arc to change as the wire flexes between the points at which it is attached to the support member. The catch is adapted to engage a portion of the trigger wire in its unflexed state and to disengage the wire when it is flexed to a predetermined extent based on movement of the wire in response to movement of the facial muscle. The catch may take the form of a short pin or shaft extending from the rear surface of the optical element. The catch may be shaped to engage the wire, for example it may include a suitably shaped recess, or the like. The

important point is that the trigger wire and catch co-operate to hold the optical element in place against tension in the spring until such time as the optical element is to be released.

At this point movement of the appropriate facial muscle results in disengagement of the trigger wire and catch, with the result that the optical element moves under the action of the spring. The portion of the trigger wire that is to be in contact with the user's skin may be provided with padding, e. g. foam, for wear comfort.

The mechanism can be configured such that the spring is relaxed in the first or second position and in tension in the second or first position respectively, as necessary.

Preferably, the mechanism is such that when the optical element is moved between these two positions the momentum of the optical element is sufficient to prime the mechanism again. The result is that the mechanism is always primed and thus ready to use in a hands- free mode at all times. This could be achieved by using two separate mechanisms of the type described in detail above.

Where the mechanism is self-priming as a result of movement of the lens between first and second positions, or vice versa, the same or different facial muscles may be used to trigger the mechanism for the lens movement required. Thus, the eyewear (and specifically the mechanism) may be configured so that repeated movement of the same facial muscle will cause the lens to flip between positions. Alternatively, the eyewear may be configured such that one facial muscle causes the lens to flip form one position to the other and a different facial muscle causes the opposite movement.

In the embodiment where the eyewear functions as spectacles/sunglasses, the eyewear will also include such other features conventionally used for wear comfort. Thus, the support member or frame may include foam padding. Usually spectacles/sunglasses also include a nosepiece include rubberised pads, and this will also generally be present in accordance with the invention. It may also be preferred for comfort for the trigger to be provided with a padded cover. This may also make it easier to actuate the mechanism for moving the optical element by increasing the area to which pressure may be applied to achieve actuation.

In this spectacles/sunglasses embodiment it is usual to have two separate optical elements (lenses) and a single mechanism responsible for movement of each optical element at the same time. It is possible however that the eyewear could include two mechanisms so that each optical element may be controlled independently. This may involve actuation using the same or different types of facial muscle for each optical element. This aspect may also require some additional user training in order to ensure that the eyewear is being controlled in the desired manner.

In a preferred embodiment the eyewear includes interchangeable optical elements. This enables the eyewear to be repaired and/or modified depending upon intended use. For example, it may be appropriate to change lenses based on a variety of daylight vision requirements. For instance, one type of lens may be suitable for eye protection in very bright light and high UV conditions (for example in a snow environment), whereas another type of lens may confer the requisite protection in a less light abundant situation. It may also be useful to introduce lenses of different colours based on environmental conditions and/or user preference. Coloured lenses are sometimes favoured for driving depending upon the conditions, and for some shooting applications. The use of laser protective and polarising lenses may also be employed should the situation require it.

In this embodiment the optical element preferably clips into and out of a suitable housing provided on the eyewear. This housing may be attached to the support member or constitute part of the support member. This is particularly advantageous as replacement of optical elements can be carried out rapidly and without the need for any specialised tools.

The various components used to construct the eyewear of the present invention will be made of conventional materials. The materials chosen should be lightweight and have the necessary mechanical properties based on intended function. The components may be available commercially, especially the optical elements.

The eyewear may include ancillary equipment depending upon use. For instance the

eyewear may include a small light, such as an LED, which provides illumination in front of the wearer. This might be useful in low light environments and in this case the optical element is likely to be a clear lens for the purpose of eye protection. Miners, pot-holers and the like might find such eyewear useful.

It may also be possible to modify the eyewear to include an in-vision display. Such systems are now fairly common and involve projection of an image onto a surface upon which the eye is able to focus. Fighter pilot helmets use such technology and it is possible that the same technology may be applied in the context of the present invention. This is more likely perhaps in a military context, where the display of on-going tactical, geographical etc. information is desirable.

It may also be possible to include as part of the eyewear a communication system, such as a radio transmitter and receiver. Such systems are also well known and it is envisaged that they could be integrated with the present invention with ease. This may be useful in military applications or in other fields where communication is important.

The present invention may be useful in a variety of situations. As noted above, the optical element may be an optical lens, such as is conventionally found in spectacles. In this case the invention allows the optical lens to be moved in front of and/or away from the eye as required. This would enable the wearer to have a range of focus depending upon whether the lens is in front of the eye or not. The present invention allows the lens to be moved in a hands-free manner, and this may be particularly attractive in certain situations.

The majority of applications involving the present invention are however likely to be ones where the optical element used has some protective function with respect to the eye. One example of such an application is where the optical element provides protection from the sun. Here the optical element may be a lens of the type usually employed in sunglasses.

Such lenses may also have optical properties in terms of also changing the effective focal length of a wearer's eyes (as in so-called prescription sunglasses). With reference to this application there are numerous instances in practice where the invention would be useful.

One example is when the ambient light conditions change when one is driving, for example on entering a tunnel from bright light. Here it would normally be necessary for the driver to remove their sunglasses, and this will involve taking at least one hand off the driving wheel or controls. The present invention avoids this seemingly innocuous but potentially hazardous exercise by allowing the sunglasses lenses to be moved away from the eye without the use of the hands.

This aspect of the invention may have particular utility in stressful conditions, and here the invention may be especially useful in military applications. For instance, a crewman in an armoured vehicle may experience a dramatic reduction in ambient light conditions when returning to the body of the vehicle after carrying out surveillance. Under stressful conditions, such as during combat, the crewman must acclimatise to the change in light conditions as soon as possible. This is conventionally done by removing sunglasses or goggles by hand. This can be time consuming and involves at least one hand. The present invention makes it possible for the dramatic change in ambient light conditions to be managed rapidly whilst freeing up the crewman's hands for operation of vehicle systems.

The present invention also has the advantage that, when not in use, the optical element is retained in a known and close by position. This avoids the problem where sunglasses or goggles are taken off and possibly misplaced, or are not readily to hand.

In summary, in situations such as the ones described where there is a rapid transition in ambient light conditions, the present invention has the following advantages: 1. The optical element is moved clear of the eye when not in use. This allows a clear field of vision and also enables the use of other optical devices.

2. The mechanism responsible for movement of the optical element is hands-free.

This enables the wearer to use his/her hands for other operations, as might be required.

3. The eyewear is retained on the wearer's head and the optical element is therefore

readily available for use, depending upon changes in light conditions.

4. The optical element of the eyewear may be interchangeable, allowing the eyewear to be repaired or customised to user and/or application.

Related to this example, the invention may also find utility in action sports such as skiing, cycling, and the like. Here it may be necessary for the participant to be able to accommodate changes in ambient light conditions very rapidly. This may be achieved in accordance with the present invention by using a tinted lens as the optical element.

The present invention is useful in a variety of other situations where eye protection is also important. For instance, the invention may be applied to provide safety gasses which prevent foreign bodies entering the eye. In this case the optical element is likely to take the form of a clear lens, for example made of a transparent plastic such as polycarbonate.

The invention is especially advantageous in situations where it is frequently necessary to remove the"lens"from in front of the eye, for example when microscope work is being undertaken. Here the invention would have particular suitability to laboratory, clinical and medical protective eyewear. As a variation of this, the eyewear may include a fixed protective optical element, such as a clear lens, and another moveable optical element such as a tinted lens. This embodiment allows changes in ambient light conditions to be accounted for whilst retaining permanent eye protection against foreign bodies via the fixed clear lens.

A further application of the present invention, already alluded to9 is in providing protective eyewear for metal working, such as welding. Here a tinted lens is used to allow the workpiece to be viewed during working and to protect the eye against sparks, and the like.

It is necessary however to frequently review the workpiece without the lens in front of the eye, for example to examine weld quality. In this embodiment the start position of the tinted lens may be up or down with movement of the relevant facial muscle causing the lens to adopt the opposite position. Thus, when the lens is initially in the up position (away from the eye), prior to commencement of welding, the eyewear mechanism is

actuated so that the lens flips to the down position for eye protection. In this embodiment it is also preferred for the eyewear to incorporate a fixed clear lens so that the user's eyes have some protection (from foreign bodies) at all times.

In a further embodiment it is possible that the eyewear of the invention is supported on a user's head in non-conventional fashion. For instance, it may be possible to secure the eyewear to the user's head in the desired position by the use of an attachment member secured to the skull or tissue of the user's head. This attachment means would allow the eyewear to be supported without the need for more visible systems, such as a spectacles frame or headband. Obviously, in this case the eyewear would need to be very lightweight for wear comfort. The materials used for the eyewear, and especially the attachment means may also need to be selected carefully for physiological compatibility. The attachment means may be fixed in place by conventional cements, as used in the medical field, or by other techniques known in the art. Care should be taken not to damage any of the facial nerves at or around the point at which the attachment means would be located.

Embodiments of the present invention are illustrated in the accompanying non-limiting drawings.

Figures 1 and 2 respectively show front and rear views of an article of eyewear (1) in accordance with the present invention. The eyewear (1) takes the form of sunglasses having two tinted lenses (2a, 2b) as optical elements. For the purposes of illustration lens (2a) is shown in a first position in which it would be positioned in front of a user's eye.

Lens (2b) is shown in a second position in which it would be positioned away from a user's eye. Each lens (2a, 2b) is attached to a frame (3) corresponding to the support member as described herein. The frame (3) is of conventional appearance although it will be noted that the lenses (2a, 2b) are not attached to the frame (3) as with conventional sunglasses.

Rather, the lenses (2a, 2b) are attached to the frame (3) by a hinge (4) which allows the lenses (2a, 2b) to be rotated relative to the frame (3) between first and second positions.

The eyewear (1) also includes a torsion spring (5) which is attached at one end to the frame

(3) and at the other end to the lenses (2a, 2b). To facilitate attachment the ends of the torsion spring (5) are L-shaped (this is clearly visible in Figure 1 for the end of the torsion spring (5) which is attached to the lens (2b) and in Figure 2 for the end of the torsion spring attached to the frame (3). Rotation of each lens (2a, 2b) about the hinge (4) relative to the frame (3) creates tension in the torsion spring (5).

The eyewear (1) also includes a trigger (6) in the form of an arcuate resilient wire. This wire is attached at either end to the frame (3) at attachment points (7a, 7b). The trigger (6) also includes a trigger pad (8) which is positioned so that it will be close to or in contact with the facial muscle chosen to actuate the mechanism by which lens movement is achieved. The trigger (6) also passes over a catch (9) which in the embodiment shown takes the form of a short pin or tab extending from the rear surface of each lens (2a, 2b).

This catch (9) co-operates with the trigger (6) so that the lens (2a in the figures) is retained in the down position. In the embodiment shown this corresponds to when the torsion spring (5) is in tension. In this position the spring (5) is trying to revert to a relaxed state by moving the lens (2a) from a down to an up position. However, the catch (9) is engaged by that part of the trigger (6) in contact with it so that this movement cannot take place. To ensure that the catch (9) and the relevant part of the trigger (6) engage with each other, the catch (9) may be provided with a recess, or the like.

In use, if both lenses (2a, 2b) are in the up position, movement of them to the down position until the trigger (6) engages the catch (9) will result in the torsion spring (5) being put in tension whilst the lenses (2a, 2b) are restrained from returning to the up position in which the torsion spring (5) would be relaxed. When the trigger pad (8) is depressed by deliberate movement of the appropriate facial muscle, the resilient wire forming the trigger (5) is caused to flex and the initial arcuate shape of the wire will change (flatten in this case). The catch (9) and trigger (6) are arranged such that this flex will disengage the trigger (6) and catch (9) so that the lenses (2a, 2b) are free to rotate upwards under the action of the torsion spring (5).

The sensitivity of the mechanism responsible for movement of the lenses (2a, 2b) may be adjusted by shortening or lengthening the effective length of the wire forming the trigger (6). This will influence the extent to which the wire flexes in response to movement of the relevant facial muscle. In the embodiment shown attachment point (7a) is provided with an adjustable locking mechanism in the form of a threaded nut assembly.