GB2370630A - Projection lamp with displaceable interrupting elements and a cowl containing apertures - Google Patents

Abstract

A projection lamp is disclosed which in use receives a light source, the lamp comprising displaceable interrupting means such as ribbons located between the source and a remote surface, the interrupting means being arranged to interrupt light from the source, and a cowl, including a plurality of apertures through which uninterrupted light rays pass so as to form images on the remote surface. The invention includes a variety of means to bring about the displacement, and a variety of cowl designs to enhance or modulate the effects of light projection. According to a second aspect of the invention a plurality of sources and associated control means are used in place to the source and interrupting means. The projected light patterns may be abstract and appear as seemingly random or may contain non-random pattern information, such as graphics or images, according to the design of the interrupting means or source control means, the source or sources and the cowl.

Description

TITLE . PROJECTION LAMP This Invention relates to a projection) lamp TECHNICAL FIELD

There are vanous devices and methods available to modulate a light source In order z that the lighting effect of the light varies with time and place These include: metal Impeller fans used in flame effect electric fires, electronically controlled dimmers and motorised'gobos'.

BACKGROUND ART An example of an apparatus for simulating flames is described in UK Patent Application GB-A-2 230 335 (BASTC ENGINEERING). A flame effect is provided by reflecting light from a lamp off a plurality of reflective ribbons that are preferably coated silk or silk-like material. Air is forced by a fan or blower unit across the ribbons in order to create a flickering light. The reflected light is then projected on to a diffusion screen placed intermediate the lamp and an observer. The screen may include smoked coloured glass or acrylic. The smoke coloured glass, when illuminated with the flickering light, produces a simulated flickering flame effect. The effect is enhanced by enclosing the blower unit and ribbons inside an airtight chamber as this prevents the reflective surfaces of the ribbons from dulling from the ingress of dust. The flame effect is made even more realistic by ensuring a stronger convection current in the central region of the ribbon array. This achieves the effect that flame activity is greater in the central region of the fire, which is indeed the case In a real fire.

Another means for producing a simulated flame effect IS descnbed and claimed In UK Patent GB-B-1 186 655 (H FROST & COMPANY LLGITED). A viewing screen is

placed intermediate a light source and a viewer Light ras are preferably.. diffused before they Impinge the viewing screen. The total amount of light from a lamp is divided between an upper region, which simulates flickering flames. and a lower region, which illuminates artificial coals. A preferred embodiment avoids accumulation of dust by enclosing the complete arrangement in an air-tight enclosure.

The aforementioned devices are expensive and complex; they also have a limited. intended function : namely to provide a simulated flame or fire effect. Other similar devices tend to repeat a pattern over time (due to their use of rotating reflective and/or diffusive assemblies) and are also relatively complex in their construction, often requiring separate drive mechanisms for the rotating parts.

A first object of the present Invention is to provide a simply constructed lamp which produces a random or apparently random dappled or speckled lighting effect and which is also capable of providing significantly more naturalistic lighting effects than has heretofore been achievable.

A second'objectofthëlhvehtion is provide a projection lamp in which a programmed or controlled movement of lighting patterns, images or logos on a remote surface is produced by controlled projection of light through an assembly of small apertures.

DISCLOSURE OF INVENTION According to the present invention there is provided a projection lamp which in use receives a light source, the lamp comprising: a displaceable interrupting means intermediate the source and a remote surface, said means being arranged to interrupt light from the source, and a cowl, including a plurality of apertures through which uninterrupted light rays pass so as to form images on said remote surface.

Preferably the cowl surrounds and encloses the interrupting means.

The present invention provides a lamp that is capable of creating random or apparently random modulation of the light source such that there is no perceived repetition to the light pattern and is of simple construction. In specific embodiments the modulation may be programmed and non-random and the projected pattern may have specific image information. Moreover because the cowl defines a plurality of small apertures, the images created are effectively formed by a series of pin-holes and are visible wherever emerging rays impinge on a surface. The practical effect of this is that no intermediate screen or surface is required by a viewer in order to appreciate the lighting effect. By aperture is meant an area through which light can pass, either completely open, or formed of a transparent, non-diffusive material. The light ray may pass undeviated or with some refraction of the light ray if the material is nonuniform in dimension or composition in that area.

The interrupting means might comprise a single flexible component, but preferably the interrupting means comprises a plurality of interrupting elements, each being displaceable one with respect to another. The interrupting elements are preferably formed of a flexible material, though they might be formed from rigid components flexibly mounted.

The interrupting elements within the interrupting means are preferably substantially or wholly opaque, and more preferably reflective on the surface directed towards the light source. This enables multiple reflections of the source to be obtained. Such multiple reflections create the illusion of a multiplicity of light sources, especially when a relatively bright localised light source, such as a metal halide discharge lamp or tungsten halogen lamp, is used. A benefit of this is that several images of the source can be formed by the same aperture.

Advantageously the interrupting elements are formed from a sheet of a flexible metallic coated material, such as Mylar (Trade Mark) which has a series of discontinuities, defined herein as cuts, slots or apertures, formed therein so as to define strips or nbbons which are suspended by means of a peripheral support.

The Interrupting elements are preferably disposed proximal the light source, such that a substantial part of the light from the source is screened from, and cannot pass directly to, an observer ; only rays which pass between them are visible. in the case that the elements are reflective, light will largely only be viewable after it has been reflected by one or more of the elements.

The interrupting means can have a plurality of layers of interrupting elements, preferably of reflective material, to create complex patterns of reflection and obscuration. It may be made up of rigid elements mounted in such a way that they

move relative to the light source.

0 The material of the reflective elements can be silvered, semi-silvered (i. e. so that direct light passes through, but oblique rays are reflected) and optionally coloured or multicoloured. Colouring is preferably chosen so as to give addition of colours when projected onto a white surface. It might have a refractive capability so that white light is refracted on passing through a coloured film before reflection. or on reflection off its surface, in order to achieve spectral effects. The reflective elements may have a smooth surface, so as to give specular reflection, or it might have a patterned surface or be physically distorted through its thickness, for instance crumpled or embossed, so as to reflect light in a non-specular manner.

Means may be provided to cause movement of the interrupting elements such that the exiting light rays appear to move in a random manner. Alternatively the elements might be moved by an actuator which provides a regular motion, the interrupting

means being designed so that such regular actuation produces an apparently'random or w 0 gu I semi-random interrupting effect. Agitation of the elements might be by a convection current produced by the light source; by convection currents from a separate heat source (If convection currents produced by the light source are inadequate), or by disturbing the interrupting elements by other means, for example a ran or a trembler dcce. an electrically dn\. en actuator, or by a combination of more than one of these The overall effect's that. tinhke devices m the pnor art, the pattern of light from the device is dappled and not predominantly regular in time or space.

The displaced interrupting elements may have a range of rates of responses to actuation, so as to produce patterns of varying speed of movement in the reflected light, superimposed on one another.

Additionally, the cowl may be arranged so that external air currents, for example from

people moving or fans or loudspeakers in operation nearby, move the interrupting p elements so as to produce the effect, either in addition to or instead of actuation internal to the device.

The means by which the interrupting elements are disturbed could be linked with sound patterns (either electrically, acoustically, or by other means). This variation can, depending on the nature of the light source, the type of material employed, and the means by which it is disturbed from its resting state, provide effects from a gentle shimmer to more agitated effects. These effects are such that they can be used to simulate natural lighting phenomena such as sunlight reflected off water or the dappled light pattern caused by light modulated by moving leaves in woodland.

Though the effect of the invention is achieved using a simple planar cowl with regular apertures, enhanced appearance and complexity of the projected light pattern depends on the design of the cowl and the choice of materials used for it. The factors involved include the following. The dimensions of the apertures will affect the size, brightness and sharpness of the projected image : the depth or thickness of the cowl material and the uniformity of the aperture within this depth, and the distance from the source at which the effective smallest dimension of the aperture lies, will also affect the size and brightness of the image, the directionality of the light paths within the aperture and the degree of attenuation of any gIven lIght ray within the aperture dimension, in the

case shore thé aperture has a non-uniform transmission, will also add to vanabiht\ in the effect. The above considerations allow the cowl to be designed to give light effects characteristic of a number of possible situations. For example, In a preferred embodiment designed to simulate lIght effects in woodland, the cowl is advantageously formed from multiple layers of random apertures, as can be achieved with a material such as plastic matting or imitation foliage.

The cowl might comprise more than one layer or component, for example layers of differing properties of light transmission or modulation or regular or irregular aperture configurations.

In an alternative embodiment, the pattern of apertures In the cowl can contain image information, for example a graphic or logo, which will be projected as part of the pattern of varying direction and/or intensity by movements of the interrupting means. This can be combined with more random aperture configurations as described above to give a mixed image effect. Image information is advantageously differently laid out on areas of the cowl in accordance with their desired appearance on the remote surface towards which that part of the cowl is orientated. This-is particularly advantageous in the case of projection onto a surface far from normal to the direction between the cowl and the surface.

The cowl might itself be flexible, for example of one or more layers of a material such as silk or other fabric, either in sheet form with apertures, or in a crumpled form or an aggregate of separate pieces held together to give an irregular array of apertures. Such a flexible cowl might be actuated by any of the means disclosed herein.

In an alternative embodiment, the cowl might comprise apertures which have defined optical properties-Diffuse behaviour of light rays as employed in the prior art is not preferred, as the projection properties of the apertures are degraded. However apertures with tensing properties, for example as found in lenticular raised areas or concentnc Freshet lens pattern embossing in some forms of plastic sheeting, are advantageous for format ! on of particular prolected patterns In preferred embodiments of the invention some patterns will be similar in time and space, but they will not be identical, and so will not be perceived as repetitive. Herein the actuation of the interrupting means, of further reflective surfaces or of the cowl is envisaged as being either random or semi-random, or alternatively with predetermined sequences in time as will result from response to external electrical information or in response to signals from recorded sound. A combination of these modes of operation is chosen to be advantageous for the location in which the lamp is to be used. A combination of semi-random and repetitive motion might be used, for instance movement, for example rotation of a first cowl in addition to one of the above means applied to a second or further cowl. A combination of apertures, formed from a

number of regular rotating motions, also produces an apparently random effect and is p envisaged as an arrangement in one embodiment. A light pattern varying according to the Moire effect can be projected onto the remote surface if the cowls have at least a partially regular pattern of apertures. In embodiments where the cowl is actuated and image information is included in the cowl design as described above, the cowl is advantageously designed so that account is taken of the effect of the movement in location of the image on the remote surface resulting from the actuation.

The projection lamp of the invention can operate with a variety of different light sources. Preferred sources are those which are localised, for example a metal halide discharge source or a tungsten halogen bulb, or a filament source of other type, or a candle. Laser sources are useable if a component is included to spread or fan the beam. such as a multi-faceted or actuatable mirror, or a corrugated reflector surface in the path of the beam in order to generate rays in a plurality of directions.

Though a single light source is heron referred to. It is understood that more than one source might be provided, with appropnate positioning of the interrupting elements in one or more locations proximal to or around the various sources The source or sources might be displaceable with respect to the other ! amp components in order to enhance the variability of the lIghting effect. A number of sources might be controlled individually or together, for example to give the effect of one or more individual sources in motion. The sources may produce differently coloured light, so as to produce colour addition effects from overlapping rays on the remote surface.

The projected image might be of the light source might itself, or the source might illuminate a transparent material bearing an image or graphics, or a solid object, allowing image content characteristic of these to be projected. Logos or other graphics can be used on reflective interrupting materials, causing these to be projected. A focusing device might be used to concentrate light onto the graphics-bearing material or light leaving from it. The source might illuminate one or more source apertures in an opaque material, so allowing the outline of the source aperture to be projected, or to allow a single source to create a number of spatially separated sources at the source apertures, each of which will be projected. The source apertures can be shaped or coloured or contain translucent image information, or logos or other graphics. The pattern of locations of the source apertures might itself contain graphic or image information and so be used to project image content characteristic of this. An advantage of this embodiment is that the sheet containing the source apertures can partition a compartment containing the light source or sources from that wherein the interrupting means is located. Therefore the sources can be cooled by air flow without this cooling flow displacing the interrupting means. The arrangement allows hotter, brighter sources to be used than in those embodiments where the source and the interrupting means are located in the same housing without a partition. In embodiments where image information is to be introduced to the light rays in such a way, and where actuation of the cowl is also included, the cowl and the image introduction means are advantageously designed together in order to retain desirable image projection characteristics for all positions of the cowl which wil) be encountered in use Accordmg to a second aspect of the mvenuon IS provided a projection lamp which in use receives a plurality of light sources, the lamp comprising a control means which acts in use to control the illumination of the sources, and a cowl including a plurality

of apertures through which light rays pass from the sources so as to form images on a 0 t : p 0 surface remote from the lamp.

The function of the interrupting means in the first aspect of the invention is to control the illumination of the apertures in the cowl by rays from the source or sources, that is it acts to control the amount of light travelling along any given path from a source to an aperture. The same function is achieved by providing a plurality of light sources, each of which will have a given light path from it to a given aperture, and a control means which controls the illumination of the various sources. The various sources have different spatial and angular orientations from a given aperture and so when a the sources are modulated the rays arriving at that aperture appear the same as those that would arise from a combination of a single source, or smaller number of sources, and an interrupting means as described above. The same will be true for all the apertures in the cowl which rays from a given set of sources can reach. Therefore the object of the invention is achieved in the same manner, with the switching or dimming action of the control means fulfilling the function of the interrupting means.

The sources can be of the same type as each other or of different types according to the style of light projection effect desired. Continuous sources, flash sources, or a combination of these can be used to provide a pattern of illumination overlaid by flashed highlights. Small, localised sources or more diffuse sources, or a mixture of these can be used to provide sharp or more diffuse lighting effects. Good results have been achieved with sources randomly arranged within the cowl, and these can be also be arranged advantageously in a regular or designed manner so that their positioning contributes to the projection effect, for example to give a variation In the effect with the angle of the remote surface relative to the lamp In a preferred embodiment the sources arc spatial arranged so as to confer specific organisation or image content to the projected pattern, for example to project graphics or logos The control means advantageously controls the sources in a random or apparently random manner, but in an alternative preferred embodiment is made to be programmable in order to produce a sequence of operation which repeats over time and to be controllable in response to external stimuli, for example sounds or externally

provided electrical information such as computer programme output or signals derived ua=e output or si als derived from recorded sound. The control means preferably is capable of using a combination of any of these modes of operation. The control means preferably is able to control the sources such that, while they are arranged in a regular manner such as a two-or three-dimensional array with regular spacing, they are illuminated together or in sequence so as to give an impression that they are located in a random, or alternatively in a specifically designed, set of positions when the resulting light pattern is projected onto the remote surface.

A projection lamp according to the second aspect of the invention optionally

additionally comprises an interrupting means as heretofore described in order to I p contribute a further light ray controlling function, particularly if response to external stimuli such as air currents in the vicinity of the lamp is desired- Other advantageous features of the first aspect of the invention, for example features of the cowl, are also envisaged in the second aspect and are part of the invention.

The lamp can be employed in fittings of any shape and be mounted on walls, floors, tables or other raised surfaces or mounted or hung from ceilings etc. It can also be configured as a portable lamp.

Preferred embodiments of the invention will now be described, by way of examples only, and with reference to the Figures in which.

BRIEF DESCRtPTION OF FIGFRES Figure la shows a vertical cross section and figure 1b a horizontal cross section of a first embodiment of a projection lamp according to the invention Figure 2a shows a vertical cross section and figure 2b a horizontal cross section of a second embodiment of a projection lamp according to the invention Figure 3 shows a vertical cross section of a third embodiment of a projection lamp according to the invention Figure 4 shows a vertical cross section of a fourth embodiment of a projection lamp according to the invention Figure 5 shows a vertical cross section of a fifth embodiment of a projection lamp according to the invention Figure 6a shows a vertical cross section and figure 6b a horizontal cross section of a sixth embodiment of a projection lamp according to the invention Figure 7 shows a vertical cross section of a seventh embodiment of a projection lamp according to the invention Figure 8 shows a vertical cross section of an eighth embodiment of a projection lamp according to the invention Figure 9 shows a vertical cross section of a ninth embodiment of a projection lamp according to the invention Figures 10 and I I are ray diagrams shoeing tight paths in two embodiments of a projection ! amp according to the invention Figure 12 is a diagram showing a cross section of a tenth embodiment of a projection lamp according to the invention, and light paths within it Figure 13 is a diagram showing a vertical cross section of an embodiment of a projection lamp according to the second aspect of the invention PREFERRED EMBODIMENTS OF THE INVENTION Figure la shows vertical cross section and figure 1b shows a horizontal cross section of a first embodiment lOa of the projection lamp according to the invention, intended to stand on a floor or other flat surface and which comprises a light source 12, shown as a tubular bulb but which might take other forms, surrounded by a light interrupting means comprising a hanging array of thin flexible strips 14 which surround the bulb so as substantially to prevent direct rays from passing from the bulb uninterruptedly to a distant location. Preferably the strips are of a reflective material such as Molar, preferably metallised, and preferably they are formed from a single piece of material with cuts or slots. The material or set of strips 14 is suspended from a frame 16 above the source, in such a way that they are free to move in response to air currents around them. generated by convection from the source 12 or arriving from outside the lamp, or to movement of the projection lamp as a whole, for example if it is mounted on a vibrating surface such as a loudspeaker.

The strips, frame and source are mounted in a housing 18 which surrounds them, the housing having apertures at either random or regular intervals around it, a preferred housing being a metal mesh cylinder. The source is supported on a member 20 which

acts also to stiffen the construction : the apparatus stands on an extension 22 to the housing below the source which also acts to provide ventilation to the interior The housing is cohered with a col 24 with a plurality of apertures smaller than those In the hoUSIng The apertures act as pinole sources by means of which Images of the source are formed on surfaces at a distance from the apparatus. The material of the cowl 24 is chosen for aesthetic effect and a density and size of aperture appropriate to form a larger or smaller density of images, of chosen size, brightness and sharpness.

Also the degree to which the strips 14 respond to external air currents is determined by the aperture size, and this can be set accordingly. While the cowl 24 is shown in figure la as being supported on a frame 18, the precise design of the cowl in this embodiment is determined by the materials used and the cowl might be of a selfsupporting material.

An example of a preferred cowl material 24 is a layer of plastic imitation box hedge mat, which acts to give a light effect reminiscent of that in woodlands. When the light is turned on, the convection currents produced by the heat generated by the bulb disturb the reflective strips which reflect the light produced by the light source in complex and random ways with the effect of casting varying patterns of light onto the hedge effect cylinder. Because the artificial hedge material is both translucent in some parts (when thin) and opaque in others (thicker areas) as well as having void spaces between the leaves, a lighting effect of varying brightness is apparent on surfaces surrounding the lamp. An optional reflector (not shown) may be placed proximal the source to direct light to the most advantageous part of the projection lamp.

Figure 2a shows a vertical cross section and figure 2b a horizontal cross section of a second embodiment lOb according to the invention, in which the parts are labelled similarly to those in figure 1. This embodiment is intended to be mounted on a wall or other vertical surface and so the housing 18 and cowl 24 are extended to cover the base of the lamp. The rear wall 26 of the lamp can be made reflective or matt as required to enhance the image projection effect. it may further be faceted or comprise further hanging reflective strips, or non-reflective strips partially obscuring a reflective

surface This embodiment might be semicircular In horizontal cross section as shown or of any other geometry Figure 3 shows a vertical cross section of a third embodlment Oc of a projection lamp according to the invention, in which the parts are labelled similarly to those in figure 1 In this embodiment hanging strips are provided of a number of different lengths, the stnps in groups 14a, 14b, 14c, suspended from frames 16a. 16b, 16c, so as to give a varied lighting effect at different positions outside the apparatus. The strips are preferably of different dimensions, spacing or degrees of mobility, allowing for different styles of projected light to be achieved at different places or heights within the room. The cowl 24 might be spatially varied to enhance-this effect. Such an embodiment is advantageously shaped to be representational and to give effects appropriate to its form, for example as a simulated christmas tree, or a more complex representational form such as a mountain or other object, or an animal.

Figure 4 shows a vertical cross section of a fourth embodiment 10d of a projection lamp according to the invention, in which the parts are labelled similarly to those in figure 1. This embodiment is intended to hang from a cord 28, and can have a single array of hanging strips, or a plurality as in the-embodiment in figure 3.

Figure 5 shows a vertical cross section of a fifth embodiment 10e of a projection lamp according to the invention, in which the parts are labelled similarly to those in figure 1 Here a fan 30 is included within the housing 18 to agitate the strips in a random manner. A fan may alternatively be provided as part of the lamp assembly mounted outside the cowl.

Figure 6a shows a vertical cross section and figure 6b a horizontal cross section of a sixth embodiment 10f of a projection lamp according to the invention, in which the parts are labelled similarly to those in figure 2. This embodiment is intended to be mounted on a vertical surface and IS similar to that n figures 2a and 2b. except that a

second flexible reflective surface 32 is provided proximal the tight source, this surface being capable of actuation by an actuator, here shown as a toudspeaer 34 which moves the surface 32 by sound, or by pressure waves below audIble frequency. If the surface 32 has discontinuities the loudspeaker might actuate the interrupting means 14 also. Alternative actuator devices may contact and move the surface directly.

Figure 7 shows a vertical cross section of a seventh embodiment 109 of a lamp according to the invention, in which the parts are labelled similarly to those in figure I.

Here the lamp assembly comprising source 12, interrupting means 14, supporting frame 16 and cowl 24 are mounted on and suspended from a further cowl comprising one or more component layers 36,38. A loudspeaker 34 actuates the interrupting means. This can be achieved by generating sound or sub-sonic pressure waves, in

which case the lower end 40 of the interrupting means is advantageously closed or restricted to maximise the displacement of the interrupting elements. In another preferred embodiment the interrupting means is suspended from or actuated directly by the moving part of the loudspeaker, in which case the support frame 16 is either attached to the moving part or is made flexible in order to allow for the movement of the interrupting means.

Figure 8 shows a vertical cross section of an eighth embodiment 10h of a projection lamp according to the invention, in which the parts are labelled similarly to those in figure 1. Here the source 12 is replaced by a multiple source formed of a plurality of sources 50 disposed within the interrupting means. The sources, which might be of more than one colour, can be controlled independently or together to produce variable projection effects.

Figure 9 shows a vertical cross section of a ninth embodiment 10i of a projection lamp according to the invention, in which the pans are labelled similarly to those in figure I.

Here the source 12 is surrounded by a plurality of rigid reflective surfaces 60, mounted on a frame 62 by flexible support means 64, such that they are free to move.

Figure 10 is a ray diagram showing the operation of the invention A source of light, shown as an object 100 represented by an arrow. creates rays which pass through openings in a displaceable interrupting means 102 comprising a plurality of interrupting elements-the elements being either flexible, or rigid, but flexibly articulated so free to move and formed of a single piece or multiple pieces. The positions and orientations of the interrupting elements are shown as at one moment in time and they, and the light paths shown, will change with time. Some of the rays, for example rays 108, pass through apertures, for example 106, in the cowl 104, these apertures being smaller in general than those between elements in the interrupting means 102. The pinhole camera effect of the small apertures means that a plurality of inverted images 110 of the object are formed on a surface distant from the apparatus.

The reflective interrupting means are shown in a linear orientation with respect to the source in figures 10 and 11 but it is understood that the interrupting means can be of any appropriate arrangement and similar principles of reflection and transmission will apply.

Other ray paths 114, through other apertures 112, will form differently sized images in general and have different degrees-of motion, according to the size and position-of the apertures in the cowl and according to variation in the mobility of different parts of the interrupting means 102. If a further reflective surface 120 is placed behind the source further light paths 124 are possible, forming further images 126. These will have a different degree of movement from those (110, 116) formed without reflection. Further and more complex paths are possible, for example those formed from multiple reflections from the source side of interrupting means 102 if this is reflective, which add to the random effect of the moving images of the object.

It will be apparent from figure 10 that the object 100 can be the light source itself, a transparent image, or a solid object illuminated by a light source, the images in each being projected onto the distant surface. If one or both of the interrupting means 102 and the surface 120 are moved for example by an actuator, then the images can be

made to move in response to externally denied stgnals The surface 120 is shown here as comprising a pluralIty of elements similar to those In the ! nterruptmg means 102. It is understood that when the surface 120 is continuous as shown In figure 6 then similar light paths will arise.

Figure I is a further ray diagram showing light paths In an embodiment of a projection lamp according to the invention. Instead of the substantial thickness of cowl material 104 shown in figure 10, the cowl might be a thin sheet 140 as shown m figure 11 and the same effect will be achieved. The apertures in the cowl might not be open, but might be transparent or translucent areas in an otherwise opaque material.

This embodiment differs from the prior art, for example in the field of fire simulators and flicker devices, in that here the intention is to project light onto a distant surface rather than to view as it appears on the cowl material-consequently, unlike in the prior art devices the transparent areas in sheet 140 are substantially or wholly nondiffusive, in order to allow light to pass without scattering so as to form the Images 142. 144.

Figure 12 is a diagram showing a cross section of a tenth embodiment 10j of a projection lamp according to the invention, and light paths within it. One or more light sources 200, 202 are mounted in a housing 205 and illuminate a sheet member 206. A reflective rear surface 204 may be provided so as to produce a substantially even illumination of the sheet 206. Sheet Z06 contains source apertures, each of which itself acts as a small light source and hence as an object, 208, 210, which can be projected by the device. The light from these source apertures passes through a displaceable interrupting surface 212 shown as a number of strips in cross section, which partially obscures the source apertures, and can shutter or if reflective, re-direct light railing onto it. Light which passes through it then passes through apertures in the cowl 214. forming images 224. 226 resulting from light paths 220. 222 respectively Further light paths 228 and images 230 can result from reflection from surface 212 and surface 206, if both are made reflective, and more and more complex paths sill also occur The source apertures in sheet 206 can be made of varying sizes. can compnse transparent sheets with colour or image informatIon and have varying outline or pattern of location so as to project the colour. Image. outlme or pattern information onto a distant surface.

Figure 13 is acMagram snowing a vertical cross section of an embodiment 10k of a projection lamp according to a second aspect of the invention, In which is provided a housing 18 supporting a cowl 24. An assembly 300 comprising a plurality of light sources are provided mounted on a support means 302, for example a wire frame or a circuit board. in turn mounted on a support member 20. The sources are shown in figure ! 3 as being in a regular array and of even size, but such an embodiment is also advantageously constructed using sources of different types and irregular location.

Advantageously sources are provided at different depths within the assembly 300 such that the patterns formed-from them have a range of characteristics when projected onto a remote surface. The assembly 300 is shown in figure 13 as occupying a significant region of the interior of the lamp. In an alternative embodiment the sources are grouped closely together so giving a more closely defined light pattern. The sources are controlled by a control means 304, shown as separate here but which is preferably incorporated into the lamp itself The control means optionally receives control information from an external source 306 of control information, such as a computer or source of recorded sound signals.

The invention has been described by way of examples only and variation may be made to the embodiments. Further advantageous embodiments can be achieved by combination of features described above for the individual example embodiments and these are within the scope of the invention.

Claims (1)

1. CLAIMS I A projection lamp which in use receives a light source, the lamp compnsmg'a displaceable interrupting means intermediate the source and a remote surface, said means being arranged to interrupt light from the source, and a cowl, including a plurality of apertures through which uninterrupted light rays pass so as to form images on said remote surface.

   2. A projection lamp according to claim 1 wherein the interrupting means comprises a plurality of interrupting elements 3 A projection lamp according to claims I or 2 wherein at least one interrupting element is flexible

   4. A projection Tamp according to any of claims 1, 2 or 3 wherein the cowl p I surrounds and encloses the interrupting means 5. A projection lamp according to any of claims 1 to 4 wherein the interrupting means comprises a reflective surface.

   6. A projection lamp according to any preceding claim wherein the interrupting means includes a reflective sheet which is flexible.

   7. A projection lamp according to claim 6 wherein the reflective sheet is formed into an arcuate enclosure.

   8 A projection lamp according to claim 7 wherein the sheet has cuts, slots or apertures formed in it. 9 A projection lamp according to any of claims 6 to 8 wherein the sheet is In the form of a right circular cylinder. to A projection lamp according to any precedmg claim comprising at least one other retlectlve surràce.

   I I A projection lamp according to claim 10 wherein the said at least one other reflective surface-is displaceable.

   12. A projection lamp according to claim 11 including a displacement means to displace at least one reflective surface with respect to the light source.

   13. A projection lamp according to any preceding claim including a displacement means to displace the said interrupting means with respect to the light source.

   14. A projection lamp according to claim 12 or 13 wherein the displacement means includes a motor and is preferably a fan.

   15. A projection lamp according to claim 12 or 13 wherein the displacement means includes a heat source and is preferably the light source itself 16. A projection lamp according to any of claims 11 to 15 wherein the displacement is controlled in response to or effected by pressure waves or sounds.

   17. A projection lamp according to any of claims 11 to 16 including a transducer so arranged as to cause a displacement in response to an external signal.

   18. A projection lamp according to any preceding claim wherein the cowl comprises a plurality of elements spaced one from another, the elements being dimensioned and arranged to define passages for light to exit therebetween and to produce patterns of spatially vaned luminosity on a surface remote from the projection lamp 19. A projection lamp according to any preceding claim in which spatial arrangement of the apertures in the cowl is characteristic of a chosen image content so as to produce patterns containing the image content on a surface remote from the'projection lamp.

   20. A projection lamp according to any preceding claim in which the cowl and the light source are displaceable one with respect to another..

   21. A projection lamp according to any preceding claim wherein means is included 03 t ; to place an image-forming object or an image-bearing element proximal the light source, so that in use a light pattern modulated by the said image-forming object or image-bearing element is projected to a location outside the assembly.

   22. A projection lamp according to any preceding claim in which the light source illuminates one or more apertures in an opaque material proximal the source, so that in use light patterns characteristic of the arrangement and nature of the apertures will be formed on a surface remote from the projection lamp.

   23. A projection lamp which in use receives a plurality of light sources, the lamp comprising a control means which acts in use to control the illumination of the sources, and a cowl including a plurality of apertures through which light rays pass from the sources so as to form images on a surface remote from the lamp.

   24. A projection lamp assembly as shown in figures 1-9 and 12 and 13 and substantially as herein described.