WO2004001286A1 - Light fittings - Google Patents

Abstract

The present invention relates to an illuminator or lighting unit that comprises a light source, a reflector and a glass cover. The invention is characterised in that the light source (2) is generally pitted or punctated; in that the reflector (3) is adapted to output parallel light; in that the surface of the glass covering (4) includes a large number of lenses (5) which each has a square or rectangular shape as seen in the direction of the light from the reflector and each of which is adapted to diffract the light asymmetrically so as to illuminate a rectangular or square area of a surface at right angles to the optical axis of said lens (5).

Description

Light Fittings

The present invention relates to an illuminator or lighting unit .

One problem with conventional illuminators, such as devices for illuminating roads, signs and for flood lighting purposes for example, is that the illuminator is dimensioned to illuminate the area intended with the result that in addition to lighting up said area there is generated a great deal of stray light that lands outside the intended area.

Another problem is that as a result of their design, conventional illuminators emit uneven luminescence over the surface to be illuminated. This means that the light source must be made strong enough to provide sufficient illumination of those surface areas that receive the least light.

These drawbacks are overcome by means of the present invention.

The present invention thus relates to an illuminator, or lighting unit, which comprises a light source, a reflector and a glass cover and which is characterised in that the light source is essentially pitted or punctate; in that the reflector is adapted to output parallel light; and in that the surface of the glass covering includes a large number of lenses which each has a square or rectangular shape as seen in the direction of the light from the reflector and each of which is adapted to diffract the light asymmetrically so as to illuminate a rectangular or square area of a surface at right angles to the optical axis of said lens. The invention will now be described in more detail, partially with reference to an exemplifying embodiment thereof illustrated in the accompanying drawing, in which

Figure 1 is a cross-sectional view of an illuminator according to the invention, and

Figures 2a - 2c illustrate a lens on a larger scale.

Figure 1 illustrates an illuminator, or lighting unit, 1 comprising a light source 2, a reflector 3 and a glass covering 4.

According to the invention the light source 2 is generally punctate. Preferred light sources are gas discharge lamps that have a high luminous efficiency and a concentrated discharge. MPXL (Micro Power Xenon Light) or CDM (Ceramic Discharge Metalhydride) are examples of such light sources. These light sources have a light spectrum that lies close to that of ordinary daylight.

According to the invention the reflector 3 is parabolic, so that light leaving the reflector will be parallel.

The surface of the glass covering 4 of the inventive illuminator includes a large number of lenses 5 of a square or rectangular shape, as seen in the direction of the light from the reflector.

The lenses 5 are shown as small protrusions in the embodiment shown in Fig. 1. The glass covering includes many lenses 5. Each lens will preferably be dimensioned to correspond to a few millimetres times a few millimetres as seen in the direction of the light from the reflector.

According to a preferred embodiment, the lenses 5 are formed on the inner surface 6 of the glass covering. The lenses are also asymmetrical.

Figs. 2a - 2c illustrate a lens 5. Fig. 2a is a front view of the lens 5, whereas Fig. 2b shows the lens 5 from above in Fig. 2a. Fig. 2c shows the lens 5 from the left in Fig. 2a.

Each lens is adapted to diffract the light so as to illuminate a rectangular or square area of a surface situated at right angles to the optical axis of the lens.

According to one preferred embodiment, the lenses 5 are formed by depressions made on the inner surface 6 of the glass covering 4 in the manufacture of said cover.

This results in lighting of very high efficiency, by virtue of the fact that the optical system comprised of said lenses 5 functions to steer the light onto the actual surface to be illuminated, therewith avoiding wastage in the form of uncontrolled stray light.

The person skilled in this field will have no difficulty in producing lenses for this particular purpose.

Moreover, unnecessary heat losses are avoided, by using a parabolic reflector of high reflectance.

Such an illuminator can be used for all sorts of purposes Examples of such use include flood lighting, sign illumination, camera studio lighting, greenhouse lighting, etc..

The invention can be applied with particular benefit with regard to greenhouse lighting, since it can ensure that each plant or growth situated within the illuminated area will be subjected to the same dose of radiation.

With regard to street lighting, the significant advantage is afforded by enabling the avoidance of "dark spots or black holes" between the illuminators, by constructing the illuminator so that it will illuminate a rectangular area of the street or road concerned. This also enables the total lighting effect to be reduced, without the loss of visibility.

The present invention thus eliminates the drawbacks mentioned in the introduction.

It will be understood that the illuminator or lighting unit shown can be given a different form and that the form of the lenses can vary.

The present invention shall therefore not be considered to be limited to the embodiments described above, since variations can be made within the scope of the accompanying claims.

Claims

Claims .

1. An illuminator, or lighting unit, which comprises a light source, a reflector and a glass cover and which is characterised in that the light source (2) is generally pitted or punctated; in that the reflector (3) is adapted to output parallel light; and in that the surface of the glass covering (4) includes a large number of lenses (5) which each has a square or rectangular shape as seen in the direction of the light from the reflector and each of which is adapted to diffract the light asymmetrically so as to illuminate a rectangular or square area of a surface at right angles to the optical axis of said lens (5) .

2. An illuminator according to Claim 1, characterised in that the lenses (5) are formed on the inner surface of the glass covering (4 ) .

3. An illuminator according to Claim 1, characterised in that the lenses (5) are asymmetrical.

4. An illuminator according to Claim 1, 2 or 3, characterised in that each lens (5) has a dimension that corresponds to a few millimetres times a few millimetres seen in the direction of the light from the reflector (3) .

5. An illuminator according to Claim 1, 2, 3 or 4, characterised in that the lenses (5) have the form of impressions made on the inner surface of the glass covering (4) during manufacture of the glass covering.