Background Art Laser cut light deflecting panels, such as those described in AU 601634 (Edmonds), are formed by making laser cuts through a clear acrylic sheet with an automatic laser cutting machine. Each laser cut becomes a narrow mirror internal to the sheet. These mirrors reflect a proportion of the light incident on the sheet in off-normal directions. Laser cut light deflecting panels have the advantage that they deflect light much more powerfully than-other light deflecting systems, such as prismatic glass. These panels can be used as window glazing to redirect sunlight towards the ceiling of the room.

Disclosure of Invention In a first aspect, the invention is a method of manufacturing illumination glazing comprising the steps of: Moulding from plastics material a self-supporting translucent 3-dimensional unitary form; and Introducing a pattern of cuts in the plastics material to redirect incident light in selected directions.

It is an advantage of the present invention that it is self-supporting, and so can be manufactured without the need for costly and cumbersome support structures.

The glazing has an outer surface which may have a smooth and uninterrupted finish. To achieve this, the step of moulding may be performed using blow moulding.

Alternatively moulding may be performed using thermoforming, vacuum forming, injection moulding or compression moulding.

The glazing may include faces that are substantially flat. The pattern of cuts may be introduced into the substantially flat faces. The pattern of cuts may be introduced by a laser cutter or a waterjet cutter cutting at angles into the plastics material. Laser cutting may involve the use of a miniature computer controlled torch

using focused laser light as the heat source to both melt and vaporize material in its path.

The glazing may be sequentially moved to position each substantially flat face relative to the cutter so that the cutter can cut each substantially flat face in sequence.

The glazing may be moved by rotation. Alternatively, the cutter may be sequentially moved to position each substantially flat face relative to the cutter so that the cutter can cut each substantially flat face in sequence. The cutter may be moved by rotation.

In one example, the glazing is formed into a skylight. When fitted to a building, it may be designed to increase the penetration of natural light into the building. In particular, it permits light to travel further into the building and creates a natural lighting effect. This in turn, reduces the requirement for artificial lighting and saves energy.

In a further example the glazing may be designed to redirect a proportion of the incident light away, in order to reduce the heat gain in the building.

The shape and pitch angle of the sides of the form may be designed to achieve different deflecting angles, to take account of these purposes and the latitude.

In another example, the glazing is formed into an artificial light fitting.

The glazing may be designed to redirect light incident on its interior or exterior, or both.

There may be more than one pattern of cuts on the glazing.

The method may further comprise the steps of : Forming from plastics material a second self-supporting translucent unitary 3- dimensional form, the second form having an inner surface complementary to the outer surface of the first form; and placing the second form on top of the first form, the complementary surfaces being adjacent.

The method may further comprise the steps of: Forming from plastics material a third self-supporting translucent unitary 3- dimensional form, the third form having an inner surface complementary to the outer surface of the second form; and placing the third form on top of the second form, the complementary surfaces being adjacent.

The second and third forms may be transparent.

The first, second and third forms may take a variety of shapes, such as a pyramid, pentagonal, hexagonal, trapezoidal to geodesic domes. The shape may be symmetrical.

The method may further include the step of setting the form on top of a base.

The base may be a conventional skylight housing.

In a second aspect, the invention is illumination glazing comprising a self-supporting translucent unitary 3-dimensional plastics form, having a pattern of cuts in the plastics material to redirect incident light in selected directions.

In a third aspect the invention is a building equipped with illumination glazing as described above.

Brief Description of Drawings Examples of the invention will now be described with reference to the accompanying drawings in which: Fig. 1 is a perspective view of a skylight having four sides; Fig. 2 is a side view of the skylight of Fig. 1; Fig. 3 is simplified cross-section through part of one side of the skylight of Fig. 1 ; Figs. 4 and 5 are simplified cross-sectional diagrams of Fig. 1 showing how the pitch of the form effects the redirection of the incident light; Fig. 6 is a perspective view of a skylight in the shape of a square based pyramid; Fig. 7 is a simplified cross-sectional diagram of a double glazed skylight; Fig. 8 is a simplified cross-sectional diagram of an artificial light fitting; Figs. 9a and 9b are a simplified perspective and simplified cross-sectional diagram of an elongated artificial light fitting covering fluorescent tubes; Fig. 10 is a simplified cross-sectional diagram of an artificial light fitting fitted to a wall; Fig. 11 is a simplified cross-sectional diagram of another artificial light fitting; and Figs. 12a and 12b are a simplified perspective and a simplified cross-sectisonal diagram of an elongated artificial light fitting covering fluorescent tubes.

Best Mode for Carrying out the Invention Figs. 1 and 2 show a perspective and side view of a skylight 10 manufactured using the method of the present invention. In this example, only one self-supporting translucent unitary 3-dimensional form 12 is used to create the skylight 10. It has a circular base and four similarly shaped sides that meet at a flat point above the centre of the base. This form 12 is made from 6mm thick acrylic and may be formed using any one of the following methods:

1. Blow Moulding In the blow moulding process, molten plastics material is extruded in the form of a vertical tube into an open mould. The tube is clamped between two halves of a mould so as to seal to the tube. Hot air is blown into the tube to inflate it so that it takes on the shape of the mould. The form is then cooled and released. The resulting form has a good surface finish and has a constant thickness of plastics at every point of the form.

2. Compression Moulding In the compression moulding process, molten plastic assumes the desired shape of the form using compression. The plastic is melted directly in the preheated mould or in a ventilated oven until the plastic is melted in a homogeneous way. The molten plastic is then placed between two halves of a heated mould. The mould is then closed and a higher pressure is applied to the mould so that the plastic is formed into the exact shape of the cavity created by the two moulds. The resulting form is then cooled.

3. Vacuum Forming In vacuum forming a sheet of plastic is heated to a temperature where it becomes very flexible. The plastic sheet is then lowered over the mould and a vacuum system pulls the plastic down tightly over it so that it assumes the same shape as the mould. The resulting form is then cooled.

4. Injection Moulding The injection moulding process involves heating and then injecting a plastics material under pressure into a closed mould. The molten plastic cools and hardens into the shape inside the mould which then opens to allow the resulting form to be ejected or removed The resulting form 12 is translucent and has a unitary structure that is self-supporting, and does not require a structural frame to support itself. The outer surface is smooth and does not bear any interruptions on the entire outer surface.

Discontinuities, by way of fine cuts spaced 4mm apart, can be cut into the plastics material of the form 12 using a laser. This can be performed with a miniature computer torch using a laser light as the heat source to both melt and vaporize material in its path. Assist gases are used to aid in additional heat generation and material removal. As a result, a vary narrow and consistent path or"kerf"is created. By varying the power, feed rate, focus, gas type and pressure the resulting laser cuts can also be varied.

A multi axis laser cutter can be used which combines 2-dimensional and 3- dimensional cutting capabilities in a single, cost-effective machine, providing

application flexibility and economy. One machine can quickly cut flat parts, shaped parts or perform bevel cutting, significantly expanding the manufacturing possibilities, from 2-dimensional to 3-dimensional processing.

The 5-axis system and the 3 axes, the laser head does two rotations: 360 degrees continuous and +/-135 degrees. It can cut at any head orientation with ease at high speed and high accuracy.

The cutter may also use a capacitance sensor that accurately and automatically maintains the standoff distance from the work surface of the glazing while adapting to account for changes in material thickness. This eliminates manual operator intervention, facilitating unattended production runs.

The cutter may also feature a magnetic breakaway system that protects against crashes. In the event of an obstruction, the head safely releases and the machine can be operational again in minutes.

All axis movements and the entire cutting process are programmed, and operated via an intuitive CNC control station with touch screen function and windows interface. They can be programmed offline with the appropriate software. In the graphic software, draw or import the pattern of cuts and the shape of the form.

The form is placed on the laser table and the laser moves around to orient itself to cut the required pattern into the flat sides of the geodesic form. The flat sides may be cut one after each other until all flat sides have been cut. The laser will automatically adjust to the correct height based on the thickness of the plastic material.

It is also possible to have the laser stationary and instead the form is rotated to orient itself so that the flat sides can be cut one after the other.

Alternatively, water jet cutting can be used to create the pattern of cuts in the form 12 by using abrasive water jets that pump very high-pressure streams of water.

The spray is channelled through a very narrow jewelled nozzle at a very high pressure to keep the spray coherent. A water jet never gets dull and does not overheat and involves a an odourless, dust free and relatively heat free process. A tiny jet stream permits the first cut to also be the final finished cut surface. This single cutting process saves material costs and machining costs. Cutting can be done under water to reduce splash and noise. Faster feed rates are used to prevent the jet from cutting all the way through. Like the laser cutter, either the water jet or the form itself can be moved around to enable all sides of the form to be cut.

The pattern of cuts redirect light incident on the form 12 in the selected directions. The pattern of cuts operate as a mirror within the plastics material, redirecting a portion of the incident light. The proportion of light that is redirected

depends on the depth of the cuts, the distance between the cuts, as well as the angle of the incoming light which may vary due to the time of day, latitude and the season.

Fig. 3 is a simplified cross-section through a part 14 of one side of the form 12 to show the redirecting abilities of the cuts 20 introduced into the form 12. The portion 14 has an inner surface 16 and an outer surface 18. A series of cuts 20 have been made through the portion 14 at an angle that is selected to redirect incident light in selected directions for that area of the form 12. Incident light from the sun travels generally in the direction 22 and passes through the outer surface 18. A proportion of the sunlight continues through the form in direction 24. A proportion of the sunlight is deflected directly downwards in direction 26 by the reflection of the cuts 20. The cuts may go all the way through the plastics material or may be part way into the plastics material. The cuts cab be introduced on either (interior or exterior) surface of the glazing.

As shown in Figs. 4 and 5, by varying the pitch of the sides of the form 12, different redirecting effects can be achieved. By varying the pitch, the form 12 is able to pick up the most useful daylight in accordance with the latitude of the form's location, and may also take into consideration heat requirements. The form 12 can be customised to the specific needs of a building so as to increase the level of natural lighting within a building. This can help to reduce the size of the skylight required.

In Fig. 4 the form 12 has a pitch of 45°. This pitch is able to redirect a proportion of the low elevation morning and afternoon sunlight 28 down the shaft of the form 12. The pitch is also able to redirect a proportion of the sunlight 30 out of the form 12 in the heat of the day. This is typically during the middle of the day when the sun is directly overhead. The ability to redirect a proportion of this light away can significantly reduce the heat gain when compared to conventional sunlights. This is particularly effective in latitudes such as the California to Florida sunbelt, where in the middle of the day only light, not heat, is desired.

In Fig. 5 the form 12 has a pitch of 35°. This pitch allows light in during the middle of the day, whilst still attracting the morning and afternoon sunlight 32 by redirecting light down the shaft of the form 12. This is highly effective in high latitudes like Canada, where heat loss is more of a problem then heat gain.

The skylight 10 of Fig. 1 is ideally used in the roofs of residential bath rooms, kitchens and dining rooms. This skylight 10 has the ability to make light travel distances around six meters or 20 feet. For example, if the skylight 10 is positioned in the roof above a top floor hallway of a two story house it will allow light into the ground floor of the same house.

Fig. 6 shows a further skylight 50 which is manufactured in the same way as skylight 10. The skylight includes a form 52 which is in the shape of a square based pyramid. The form 52 is set on top of a square shaped base 54 encased in standard skylight housing. This skylight 50 is ideally used in supermarkets, commercial, retail, light industrial, industrial and schools.

Fig. 7 shows a simplified cross-section of a double glazed version 60 of the skylight shown in Fig. 1. A further form 62 is placed directly above the cut form 12.

The further form does not bear any cuts and is transparent. The two forms are coupled together by their bases which are encased in conventional skylight housing 64.

A pattern of cuts can also be introduced into the form in a manner that it is able to redirect light that is incident upon the inner surface of the form. This is particularly suitable for artificial light fittings, such as covers for fluorescent lights. The forms can be manufactured into any shape as required by the light fitting. The light fitting forms are manufactured in the same way as described above, with the pattern of cuts introduced to suit the specific redirection requirements of the light artificial. The requirement may be to redirect the artificial light to the side, rather than toward the ceiling, to better diffuse the light around a given area or to redirect light up and towards the ceiling rather than to the side.

Figs. 8 to 12 show different examples of the form as an artificial light fitting where it redirects light incident on the inner surface of the form. Fig. 8 is a simplified cross-sectional view of a artificial light fitting 70 on a hanging ceiling light 72. The artificial light fitting 70 is a 3-dimensional light deflecting form orientated with the base at the top. The artificial light 74 generated by the ceiling light 72 is redirected by the light fitting 70 away from the ceiling 76 towards the side. The helps to better diffuse the light around the room.

The same applies to the artificial light fitting 80 of Figs. 9a and 9b which is an elongated and covers fluorescent light bulb tubes 82.

A further example is shown in Fig. 10, where the artificial light source 72 is attached to the wall 86, and the light fitting 84 redirects the light away from the ceiling 76, and instead deeper 74 into the room, and away from the wall 86. Alternatively, the light fitting 84 may have the pattern of cuts arranged so that it directs all the incident light from the source 72 directly up to the ceiling 76.

The form can also be used in any orientation to achieve similar results. For example, Fig. 11 shows the form used as an artificial light fitting 90 that redirects incident light from the source 72 to spread it further away 74. Again, the form could be used to direct the light directly down, with minimal spread. An alternative design is

also shown in Fig. 12a and 12b where the light fitting 92 is elongated and covers fluorescent light tubes 72.

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 examples without departing from the spirit or scope of the invention as broadly described.

For example, the form can be created with any shape base and with any number of sides.

Further, the sunlight can be triple glazed by placing three forms one on top of the other, with only the most inner form bearing the pattern of cuts.

The width of the plastics material used to create the form may be varied, and also the distance between the laser cuts may be varied to deliberately create a different redirecting effect.

The present examples are, therefore, to be considered in all respects as illustrative and not restrictive.