NZ517097A

NZ517097A - Luminaire providing diffused wash of light over a ceiling surface

Info

Publication number: NZ517097A
Application number: NZ517097A
Authority: NZ
Inventors: Trevor James Murray
Original assignee: Energy Man Ltd
Priority date: 1999-05-13
Filing date: 2000-05-12
Publication date: 2004-11-26

Abstract

A light fitting directs light 23 from tube source 12 via reflective panels 11A, 21A and substantially vertically oriented diffusers 24 across and towards the ceiling C adjacent to which the fitting is mounted. The light only exits the main body of the fitting via the two apertures covered by the diffusers which serve to seal the interior of the main body and thus the light source and reflective panels from intrusion of dust.

Description

<div class="application article clearfix" id="description"> 5170 97 WO 00/70264 PCT/NZ00/00072 IMPROVEMENTS IN LIGHT FITTINGS BACKGROUND TO THE INVENTION 5 The present invention relates to improvements in light fittings. As the use of personal computers with visual display units (VDUs) has become more common, it is now desirable for office 10 lighting to be provided which minimises glare on the VDU screen. Glare can occur from overhead lighting which emits light at an angle greater than 50° or 60° (all angles described herein are with reference to the vertical unless stated otherwise). 15 Light rays at this angle or greater bounce off VDU glass into the eyes of the user and can make reading the screen difficult (dependent on the intensity of the light). 20 To overcome the problem of screen glare the obvious solution is to utilise light shades which restrict light to less than a 60° beam. This light cut-off angle has an unfortunate side-effect that the upper walls and ceiling of the office become oppressively dark and uninviting. 25 To overcome the oppressive darkness created by light shades, WO 00/70264 2 PCT/NZ00/00072 'up-lighting" has been used to direct light upward from the light fitting to illuminate the ceiling. However, in order for this technique to be successful the 5 ceiling height of the office has to be about 3 metres high otherwise the effect of the up-lighting becomes a hot spot and creates annoying reflective glare. One will appreciate that not all office ceilings will be 3 metres high. 10 If the fitting is located close to the ceiling, patchy light spots result. Alternatively, if fittings are located too low then head room and room aesthetics may be affected. Furthermore, any horizontal elements located on top of known 15 *up-lighting" fittings can become dirty very quickly and cause premature performance and hardware degradation. ;Another method of providing ceiling lighting involves using strip lighting within an "encove" adjacent the ceiling. To 20 some degree the strip lighting creates a lightened effect across the ceiling however often only the corners appear bright and the remainder of the ceiling is still dark. ;Furthermore, the gaps between adjoining strip lights can 25 cause dark or unevenly lit patches on the visible portion of the ceiling. To remedy this, it is common to overlap the ;strip lights so no "gaps" are visible in the light projected onto the ceiling. It will be appreciated that this method is complicated to design and time consuming to install. Cost can also be a factor. ;SUMMARY OF THE INVENTION ;An object of the present invention is to provide a light fitting for lighting of the ceiling that enables a uniform ^wash' of light for desirable aesthetic effect. Preferably the light fitting can be mounted close to a ceiling. ;In a first broad aspect of the invention there is provided a light fitting comprising a main body for mounting adjacent to a ceiling, a lighting device within the main body, the main body having two apertures through which light from the lighting device emits, a substantially reflective surface optically arranged to only direct light from the lighting device through said two apertures and across the ceiling, the main body being substantially sealed from the intrusion of dust and including diffusers mounted with the main body to cover said two apertures, said diffusers being arranged at an angle close to vertical, wherein the reflective surface includes reflective panels located substantially above and ;SPEC 1607 ;FEBRUARY 2004 ;below the lighting device to direct light outwards towards and across the adjacent ceiling. ;Preferably the apertures are provided in an upper wall of the 5 main body. In the preferred form of the invention each of the apertures includes at least one prism. ;According to preferred embodiments of the invention the lighting device can be a strip lighting device or a bulb. 10 When strip lighting is used the main body is elongate. ;Preferably the reflected surface is curved. ;Preferably the panels are curved. ;15 ;Preferably each of the diffusers is provided between said reflective panels at a respective one of said apertures. ;BRIEF DESCRIPTION OF THE DRAWINGS ;Figure 1 is an end elevation view of a preferred 20 embodiment of a light fitting according to the first broad aspect of the present invention, ;Figure 2 is an end elevation view of a second embodiment of a light fitting, according to the first broad aspect of ;SPEC 1607 ;FEBRUARY 2004 ;WO 00/70264 ;5 ;PCT/NZOO/00072 ;of the present invention, ;Figure 3 is an end elevation view of a third embodiment of a light fitting according to a first broad aspect of the present invention, ;Figure 4 is a perspective view of the light fitting illustrated in Figure 3, and ;Figure 5 is a side elevation view of a light fitting according to the second broad aspect of the present invention. ;DESCRIPTION OF THE PREFERRED EMBODIMENTS ;Figure 1 illustrates a light fitting 10 constructed from a main"body 11 which houses a standard light source 12. The light . source 12 in this preferred embodiment is a strip light, however other "bulb" lights may also utilise the present invention. ;Light 12 is housed within a cavity 13 of main body 11 which includes a reflective curved surface 13a. Light 12 is positioned within the cavity 13 such that its light rays 17 may only exit the main body 11 at a maximum of 60° (as seen by the dotted detail lines 17). Controlling light angles in ;WO 00/70264 ;6 ;PCT/NZOO/00072 ;this way is well known. ;The enclosure of light 12 within cavity 13 has the effect of restricting the light rays 17 so that they do not cause glare 5 onto VDU screens as outlined in the preamble. Preferably, the substantial surface 13a of cavity 13 is reflective (including above the position of light 12) to direct light downwards as brightly as possible. It is also usual that a diffuser (not illustrated) be located at the opening of 10 cavity 13. ;The exception to the above reflective covering of surface 13a is the apertures 18 formed in an upper wall 11a of main body 11. In the embodiment illustrated by Figure 1, apertures 18 15 are formed substantially at the same level with the light 12 such that horizontal light 19 may exit the main body 11 horizontally (or at least at a shallow angle.with reference to a ceiling C). ;20 It will be apparent from Figure 1 that this light 19 will illuminate the ceiling C to which upper wall 11a is fixed. As the angle of light 19 hitting the ceiling C is gentle, a "wash" effect is achieved which preferably avoids any undesirable patches of light. ;25 ;The embodiment illustrated by Figure 1 utilises prisms within ;WO 00/70264 ;7 ;PCT/NZ00/00072 ;apertures 18 to direct and disperse light as is known to those skilled in the art. ;The prism (18) has the effect of bending light 19 slightly 5 upward toward ceiling C. Use of prisms is preferable but not essential to the invention as light 19 will still exit aperture 18 without the aid of a prism. ;The light fitting 10 as embodied by Figure 1 thus provides a 10 construction which eliminates glare on VDU screens below (by virtue of the restricted light angle 17) yet allows a soft wash of ceiling light (by virtue of apertures/prisms 18 and light 19 passing therethrough). Light upon ceiling C creates a more comfortable working environment. Furthermore, the 15 light fitting is mounted substantially closer to the ceiling than was otherwise possible with existing fittings. ;Figure 2 illustrates an alternative embodiment of a light fitting according to the invention. Where possible the same 20 numerals are used to describe the components as shown by Figure 1. ;Figure 2 illustrates a recessed light fitting 10A with a main body 11. Light fitting 10A is recessed into ceiling C to 25 disguise the bulk of main body 11 (including control gear G). ;WO 00/70264 ;8 ;PCT/NZOO/00072 ;The layout of cavity surface 13a in Figure 2 is comparable to Figure 1 in that the light 12 is located to restrict the majority of emitted light 17 to 60° or less. ;5 Light fitting 10A includes prisms 20 at the open mouth of cavity 13 which manipulate light 19 and bend it back towards ceiling C. The end result is a light 'wash" of ceiling C the same as the first embodiment illustrated by Figure 1. ;10 This second embodiment 10A generally is less obtrusive into a room but achieves the same effect of minimising VDU screen glare while sufficiently illuminating the ceiling for desirable aesthetics. ;15 A further embodiment is illustrated by Figures 3 and 4. ;The light fitting 10B- is intended solely for 'up-lighting" where a ceiling C may be . illuminated for visual effect. There is no downward travel of the light rays to illuminate 20 the remainder of the room. ;Light fitting 10B is principally comprised of a main body 11, housing control gear G, a light source 12 and a lower curved reflector panel 21 (in addition to reflective upper wall 25 11a) . ;WO 00/70264 ;9 ;PCT/NZOO/00072 ;As seen in Figure 4, the curved reflector 21 is connected to main body 11 via an end piece 22 fixed by suitable fastenings 23. End pieces 22 are preferably not translucent or transparent such that light 23 is only emitted through side 5 openings 24 in a controlled manner. ;Curved reflective surfaces 11a and 21a (located facing one another) on the main body 11 and panel 21 respectively direct light 23 substantially horizontally or toward ceiling C. 10 Each surface 11a and 21a is optically designed to direct light away from the interior of a room (thereby preventing glare) and to maximise light output from the light source 12. ;The gentle" angle of light 23 upon ceiling C creates a 'wash" 15 effect of light comparable to the previous embodiments shown by Figures 1 and 2. ;Side openings 24 may include a luminous cover to prevent dust particles from entering the fitting 10B. The embodiment 20 illustrated by Figures 3 and 4 include a cover over openings 24 which utilise prisms for optimum light distribution, glare prevention and generally more control over the direction of light exiting fitting 10B. ;25 ;The third embodiment 10B provides an improved construction which overcomes problems associated with previous *up- WO 00/70264 10 PCT/NZOO/00072 lighting" designs. No light patches or hot-spots are created by this present invention. Figure 5 addresses a method for installing lighting into an 5 'encove" E adjacent the ceiling. A light fitting 25 includes a light source 12, a reflector 2 6, a diffuser 27 and control gear G. 10 The diffuser 27 as illustrated is at an angle close to the vertical such that dust collection as far as possible is minimised. As can be seen clearly by arrows 28, light rays are directed across the ceiling C evenly. 15 Diffuser 27 also ensures that adjacent - light- fittings 25 located end-to-end create an even light wash such that no 'gaps" are noticeable when viewed from within the room. Conventional naked strip lighting tends to cause harsh black spots or 'gaps" between lighted areas. 20 It will be appreciated that the light fitting 25 itself will not be visible from the ground. The only visible effect will be an evenly lit ceiling. 25 Overall, the embodiments of the present invention described herein include the common feature of light directed WO 00/70264 11 PCT/NZOC/00072 substantially horizontally to "wash" a surface in light. The constructions described represent an improvement over previous designs or at least provide an alternative lighting option for the public. 12 </div>

Claims

<div class="application article clearfix printTableText" id="claims"> CLAIMS; INTELLECTUAL PROPERTY OFRCE OF M.z 2 5 FEB 2004 RECEIVED

1. A light fitting comprising a main body for mounting adjacent to a ceiling, a lighting device within the main 5 body, the main body having two apertures through which light from the lighting device emits, a substantially reflective surface optically arranged to only direct light from the lighting device through said two apertures and across the ceiling, the main body being substantially 10 sealed from the intrusion of dust and including diffusers mounted with the main body to cover said two apertures, said diffusers being arranged at an angle close to vertical, wherein the reflective surface includes reflective panels located substantially above and below 15 the lighting device to direct light outwards towards and across the adjacent ceiling.

2. The light fitting of claim 1 wherein each of said diffusers is provided between said reflective panels at a 20 respective one of said apertures.

3. The light fitting of claim 1 or 2 wherein said apertures are in an upper wall of the main body. SPEC 1607 FEBRUARY 2004 13

4. The light fitting of claim 1, 2 or 3 wherein each of said apertures includes at least one prism.

5. The light fitting of anyone of claims 1 to 4 wherein the main body is elongate to receive a strip lighting device.

6. The light fitting of anyone of claims 1 to 4 wherein the lighting device is a bulb.

7. The light fitting of any one of claims 1 to 6 wherein the reflective surface is curved. *

8. The light fitting of any one of claims 1 to 6 wherein the panels are curved.

9. A light fitting as claimed in claim 1 substantially as herein described with reference to Figures 3 and 4 of the accompanying drawings. ENERGY MANAGEMENT LIMITED By its Attorneys DON HOPKINS & ASSOCIATES SPEC1607 FEBRUARY 2004 </div>