Background to the Invention A significant percentage of the population require eyeglasses having prescription lenses to correct imperfect vision, for example, to correct short-sightedness, long- sightedness or astigmatism. Such imperfect vision may occur at birth or be a result of a medical condition and/or the ageing process. As well as meeting these basic categories of vision correction, the eyeglass wearer also has a need for further vision correction or modification to adapt the vision to particular conditions. For example, reduction of light intensity as provided by sunglasses is desirable at certain times and locations but not others. In some instances, there may be a need to temporarily increase magnification, for example, when a person is operating a computer. Another example is the use of yellow tinted lenses to improve night vision whereas their use is not desirable during daylight or in the presence of indoor lighting.

One option for the eyeglass wearer is to carry additional appropriately modified eyeglasses in anticipation of encountering differing viewing conditions. In each case, relatively expensive prescription lenses, modified to address the particular condition, are required. Apart from extra cost involved, the eyeglass wearer has the inconvenience of having to carry additional pair (s) of glasses with the attendant risk of mislaying or damaging the extra pair (s) that are not worn at the time.

Clip-on eyeglasses have been suggested as an alternative to carrying multiple pairs of prescription eyeglasses. One obvious advantage of clip-ons is that there is potential for fabricating a clip-on that is lighter and less bulky than prescription eyeglasses and therefore easier to carry. Another advantage of clip-ons is that they are generally less expensive to manufacture in that there is no need for the lenses to replicate the prescription of the eyeglass. Moreover such clip-ons can be used in conjunction with any eyeglass, irrespective of its prescription.

As a result, there are a number of different clip-on eyeglasses available in the market. However, many of these are provided with a frame which, when worn with eyeglasses, are heavy and bulky as the wearer is in effect having to wear two frames.

Another type of clip-on is one having two or four mounting clasps for gripping on to the prescription eyeglasses. There are clip-ons that are frameless, but in these cases, they usually are supplied with an obvious lens holder. Typically, the bridge member has a

grip that needs to be gripped onto the lens of the prescription eyeglasses, or alternatively, the bridge member extends above the lenses in addition to two or four mounting clasps for gripping onto the prescription eyeglasses. Eyeglasses that are currently popular have a single bridge frame, with the bridge located at a height that is below the upper edge of the lenses. In such cases, the conventional clip-on eyeglass results in a detrimental change to the original appearance of the spectacle frame, as the single bridge frame becomes a double bar frame. In such cases, the effect is aesthetically displeasing. Most eyeglass wearers select an eyeglass frame that best complements their face. Such "designer"frames can be very expensive. Having made a not insignificant investment in aesthetically pleasing eyeglass frames, it would clearly be undesirable to have a clip-on accessory that detracts from the appearance of the eyeglasses to which it is attached.

Disclosure of the Invention In a first aspect, the present invention provides a clip-on accessory for superimposing auxiliary optical elements on lenses of a pair of eyeglasses, which eyeglasses have first and second lens regions supported in a side-by-side relationship by supporting means including a bridge element, the clip-on accessory comprising: first and second auxiliary optical elements, each having an upper edge, a lower edge and a front and back; a one-piece clip joining the first and second auxiliary optical elements, forming a unitary structure, the one-piece clip comprising: a bridge member having an elongated main portion that is offset rearwardly relative to the backs of the auxiliary optical elements; left and right downwardly extending arms, the left and right arms terminating in frame engaging means for engaging the frame member of the pair of eyeglasses; and optical element holding means.

In second aspect the present invention provides a one-piece clip for use in a clip- on accessory for superimposing auxiliary optical elements on lenses of a pair of eyeglasses, which eyeglasses have first and second lens regions supported in a side-by- side relationship by supporting means including a bridge element, the clip-on accessory comprising: first and second auxiliary optical elements, each having an upper edge, a lower edge and a front and back, wherein the one-piece clip joining the first and second auxiliary optical elements, forming a unitary structure, the one-piece clip comprising:

a bridge member having an elongated main portion that is offset rearwardly relative to the backs of the auxiliary optical elements; and left and right downwardly extending arms, the left and right arms terminating in frame engaging means for engaging the frame member of the pair of eyeglasses; and optical element holding means.

The term"eyeglass"as used herein and in the claims is not to be taken as relating only to those eyeglasses having glass lenses but is to be understood as extending to eyeglass having lenses formed from other material, for example, plastic lenses.

As indicated above, the elongated portion of the bridge member is offset rearwardly relative to the backs of the auxiliary optical elements. This condition is met when the elongated portion is to the rear of the plane in which the back of each optical element lies. Preferably, as shown in the embodiments of the invention described below, the elongated portion extends between the optical elements in a plane to the rear of, and substantially parallel to, the plane in which the backs of the optical elements lie.

The bridge member preferably includes left and right rearwardly extending portions that join the elongated main portion to the respective left and right downwardly extending arms. Most preferably, the rearwardly extending portions are angled downwardly toward the elongated main portion of the bridge member so that when the clip-on is in position on the eyeglass frames, the elongated portion is located to the rear and below the upper surface of the eyeglass bridge to hold the top of the clip-on in place.

Preferably the bridge member is located below the plane containing the upper edges of the first and second auxiliary optical elements.

The frame engaging means may be in the form of prongs designed to engage a portion of the frame so as to hold the bottom portion of the one-piece clip to the eyeglass frame. The prongs may be formed by bending the free ends of the clip. The prongs may be covered or coated with a material that prevents scratching of the eyeglass lenses, for example, a silicone polymer coating or sheath.

The one-piece clip may join the first and second auxiliary optical elements by means of one or more optical element holders associated with each downwardly extending arm of the one-piece clip. The optical element holders may be welded, glued or otherwise bonded to each downwardly extending arm. Preferably the optical element holders are located on the downwardly descending arms adjacent to the rearwardly extending portions of the bridge portion.

The optical element holders may in turn be affixed to the optical elements by any suitable means. For example, the holders may be glued to the back of each optical element so that the holder is hidden behind the optical element. The optical element

holders may be in the form of coupling means, which may be a plate or the like horizontally extending from each downwardly extending arm.

Preferably the optical element holders are in the form of screw-in type couplings, within which a portion of an edge of the optical elements may be sandwiched. The advantage of the latter arrangement is that it allows semi-permanent attachment of the optical elements to the one-piece clip. Hence, the same lens holder can be used to mount various types of optical elements, for example, tinted lenses or reading or corrective lenses.

Alternatively, each optical element holder may be in the form of an eyeglass wire (very thin), which forms a frame in which the optical elements are fitted. The eyeglass wire may be closed up around the optical element by means of screws. In a further alternative, the optical element holder may comprise eyeglass wire which forms part of the frame, with the other half being an elasticised string or filament. Preferably, the eyeglass wire forms half the frame, and the elasticised string in nylon.

Preferably the downwardly extending arms are sized and shaped so that they can be hidden behind the optical elements. For example, where the inner edges of the optical elements are curved, the left and right downwardly extending arms may curve outwardly so that they are located behind the optical elements, and terminate at or above the lower edge of the optical elements to minimise the visual impact of the optical elements. More preferably, the downwardly extending arms approximate the curvature of the inner edges of the optical elements. Alternatively, where the inner edges of the optical elements are angular, the downwardly extending arms may be similarly angled and located behind the respective optical element.

The one-piece clip may be made from any suitable material. The one-piece clip may be formed from the one material or a combination of materials. Preferably, the material is a flexible, resilient material, for example, a metal. The one-piece clip may be formed from a single wire. Preferably, at least the bridge member and the downwardly extending arms are formed from a springy material so that they can resiliently engage the frame of the pair of eyeglasses. The spring force of the arms securely retains the one- piece clip onto the eyeglass frame. Preferably, the one-piece clip is formed from a super elastic alloy material which has a memorised ability to ensure that that the bridge member and the frame engaging means retain the angle and spring force for an extended lifespan. The clip may also be coated with a plastic and the engaging means preferably have a silicone or the like protector to prevent scratching of the spectacle frame.

The optical elements may be any optical device that modifies an image or light, for example, the elements may be tinted and/or polarised as in the case of conventional

sunglasses. The optical means may be capable of magnifying images or perform any other image correction/modification function.

In its preferred form, the present invention provides a new type of clip-on which solves many of the problem associated with prior art clip-ons insofar as it is lightweight and frameless, with minimal interference with the spectacle frame thereby retaining the original profile of the spectacle frame. Consequently, after the frameless clip on eyeglass is fitted, the appearance of the spectacles remains tidy and no projecting section is seen.

Brief Description of the Drawings In order that the present invention may be more readily understood, we provide the following non-limiting embodiments, which are described in reference to the accompanying drawings in which: Figure 1 is a schematic drawing showing a front profile view of an embodiment of a clip-on accessory in accordance with the invention; Figures 2 to 2C are front profile, front, rear profile and rear views respectively of a one-piece clip in accordance with the invention; Figure 3 is a plan view of a clip-on accessory in accordance with the invention located in position on an eyeglass frame; Figure 4 is a detail of one form of optical element arrangement in accordance with the invention; Figure 5 is a front view of an embodiment of a clip-on accessory in accordance with the invention; Figure 6 is an exploded view of an embodiment on a clip-on accessory in accordance with the invention; Figure 7 is an exploded view of a one-piece clip-on in accordance with the invention; and Figure 8 is a profile view of the juxtaposition of a clip-on accessory in accordance with the invention and a spectacle frame.

Embodiments of the Invention Turning to Fig. 1, clip-on accessory 10 has a one-piece clip 2 formed from a single piece of wire. The clip includes an elongated bridge portion 3 and downwardly extending right and left arms 6,8, terminated by prongs 14,16, which are coated with a silicone plastic to prevent scratching of optical lenses of the eyeglasses to which the frame is clipped. The optical elements 22,24 (broken lines) are held in position by optical element holders 26,28.

Figs. 2 to 2C show various views of a one-piece clip in accordance with the invention. The clip 20 has an elongated bridge portion 31, connecting downwardly angled portions 32,33 and downwardly extending left and right arms 34,36 terminated by left and right prongs 38, 40. The prongs are hooked so as to hook onto the base of the eyeglass frame 9 (not shown).

Fig. 3 shows a clip-on accessory 50 in accordance with the invention clipped onto an eyeglass frame 60. It will be seen that the elongated member 51 of the bridge member passes over the bridge of the bridge 62 of the eyeglass frame, and the left and right prongs 53,55 are clipped under the base of the eyeglass frame to retain the a clip-on accessory in position.

Fig. 4 is a detail of a coupling arrangement in accordance with the invention where optical elements 71,73 are retained in the a clip-on accessory 100 by means of screws 76 passing though the lenses via plates 75 attached to the downwardly extending arms 79 of the one-piece clip adjacent to the rearwardly extending portions of bridge and opposed plates 77.

Fig. 5 shows an embodiment of a clip-on accessory 100 in accordance with the invention showing the location of the left and right downwardly extending arms 102, terminated by prongs 104, behind the lenses of the clip-on accessory 100, effectively hiding all elements of the accessory, apart from bridge portion 109 and outside coupling plates 110.

Figs. 6,7 and 8 are side views showing the various elements of a clip-on accessory 150 in accordance with the invention. The one-piece clip has a bridge member 151 made up of an elongated portion 153 and left and right downwardly angled portions 155 and left and right downwardly extending arms 157.

Optical element 158 is held within the clip by means of screws 201 passing through holes 203,205 of the connection plate 207 and lens 158 respectively.

Fig. 8 show an embodiment of clip-on accessory in accordance with the invention prior to being clipped on the eyeglass frame 700.

It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.