GB2422681A - Moving lighting effect and apparatus and method therefor - Google Patents

Abstract

A method and apparatus for creating a moving lighting effect which uses a non-liquid surface 14 that simulates water having gentle waves moving thereacross. Light is reflected from the surface while the surface is manipulated so as to provide a projected pattern 28 that resembles a glistening effect found in nature. A plurality of actuators 16 on the underside of the surface are preferably used to manipulate the membrane and various options are disclosed for positioning the light sources 24, 26 or providing inputs to the system.

Description

MOVING LIGHTING EFFECT AND APPARATUS AND METHOD THEREFOR

The present invention relates to a method of creating a moving lighting effect and to apparatus useful in implementing the method. The invention is particularly applicable to obtaining a glistening effect similar to that obtained when light is reflected or refracted by the surface of water having gentle waves moving thereacross.

The glistening effect associated with the interaction of light rays with the surface of non-still water has been found to be particularly attractive and relaxing.

The light display obtained resembles numerous tiny mirrors flashing at the observer.

The position and magnitude of the reflections change slowly with time and also change as the mover moves relative to the light source.

Numerous attempts have been made to provide an artificial glistening effect.

The prior art efforts generally provide a container of water and a light source. There is further provided some means to agitate the water. Light from the light source is either reflected from the surface of the water or refracted through the agitated water in order to provide an image reminiscent of the glistening effect that one sees when sunlight strikes the surface of gently moving water. US 4,985,811, JP 200 1- 305648A, GB 2,362,454A, JP 3-093102A, JP 3-138802A, JP 5-225804A, JP 10- 1346 1OA and JP l0-134609A all disclose apparatus which use actual water to create a moving lighting effect.

Such apparatus has the disadvantage of using real water. Thus, the apparatus must be filled with water by the user prior to use or must be shipped pre-filled with water. In the case where the apparatus is prefilled, efforts must be made to ensure that the container for the water is sealed and strong enough such that it will not breach under the normal stresses and strains of transport. Furthermore, such devices suffer from the disadvantage that limescale can build up in the container obscuring the effect and bacteria can grow in the water, particularly when light is shone on or into the water. The water thus needs to be changed and the container need to be

I

cleaned.

Systems using actual water suffer from a lack of tolerance and control. The prior art systems rely on providing a certain amount of energy to the water and assuming that this will provide agitation that causes the desired effect. The actual pattern formed cannot practically be predicted and can be influenced by the outside environment. For example, vibrations external to the system can influence the pattern produced, as can the depth of water.

Furthermore, these prior art systems must, of necessity, be of a certain size in order to achieve the desired effect. The water waves provided by the agitation have a size determined in part by the natural frequency of the system and attempts to scale down the water tank result in fewer waves being produced across the area of the tank.

This can prejudice the obtaining of a glistening effect.

The surface of the water cannot be provided in any plane other that a horizontal one. This limitation affects the freedom of the user to place the device where he chooses and tends to mean that the device has large horizontal dimensions.

DE 201 19562U discloses a lighting unit which blows air across a membrane to generate chaotic instabilities in it. The irregular wavy motion of the membrane is used to reflect light so as to provide a moving lighting effect. Although this system overcomes some of the disadvantages of the prior art that use water, it does so at the expense of achieving a proper glistening effect. The movements achieved do not simulate glistening. This prior art also still suffers from the problem that the pattern obtained is unpredictable and cannot be controlled precisely. Further, this system is also susceptible to interference from outside vibrations. The air fan used to provide the chaotic movement to the membrane can also create noise and undesired airflow in the room in which it is installed.

It would therefore be beneficial to provide a system for creating a moving lighting effect that at least partially alleviates at least one of the problems of the prior art.

In a first aspect, the present invention provides a method of creating a moving lighting effect using light incident on a surface. The method preferably comprises: manipulating said surface when light is incident thereon by using a plurality of actuators; whereby the subsequent path of said incident light is modified by said surface so as to create said moving lighting effect. The surface is preferably non- liquid, such as a solid or a gel.

The use of a plurality of actuators to manipulate the surface allows greater control over the deformation of the surface. Numerous different surface shapes can be provided and changed in real time, including surface shapes that resemble the shape of the surface of water as waves move gently across it.

In a second aspect of the invention there is provided a method of creating a moving lighting effect using light incident on a surface, said method preferably comprising: manipulating said surface when light is incident thereon, said manipulation being controlled such as to cause said surface to assume a predetermined shape that varies predictably with time; whereby the subsequent path of said incident light is modified by said surface so as to create said moving lighting effect.

The controlled manipulation of the surface shape allows the influence of outside vibrations or the like to be minimised. Because the light is modified (reflected or refracted) by a surface that is non-liquid, external interference is much less of a problem.

Preferably, the plurality of actuators used to manipulate the shape of the surface span the whole of an area of the surface over which light is incident in use.

The actuators are conveniently arranged in a regular matrix, such as a rectangular or hexagonal matrix. The actuators are conveniently arranged to provide for displacements of the surface in a direction perpendicular to the neutral plane of the surface.

Each actuator preferably receives a separate actuation signal from a system controller, which is typically embodied by a microprocessor. The independent control of each actuator allows various shapes to be applied to the surface.

Furthermore, the shape of the surface can be varied with time in a predetermined fashion so as to provide the desired moving lighting effect.

Light incident on the surface can have its path modified either by being reflected from the surface or by being refracted through the surface. The subsequent light will be endowed with a moving lighting pattern based on the shape of the surface at the time of incidence. This subsequent light can be allowed to impinge on a viewing surface, such as a wall, so as to be further reflected into the observer's eye.

In this way, the lighting effect can be projected so as to magnif' it.

The controller can be pre-progranimed with various lighting effect programs that dictate the position of the surface at various points in time.

The invention is preferably arranged such that the resultant moving lighting effect simulates the glistening obtained when light shines on water having gentle waves moving thereacross.

A third aspect of the invention provides apparatus for creating a moving lighting effect, said apparatus preferably comprising: a surface; a plurality of actuators which act to manipulate the shape of said surface; a controller arranged, in use, to provide signals to said actuators so as to cause said surface to assume a shape that varies with time such that said moving lighting effect is created in light whose subsequent path has been modified by said surface.

A fourth aspect of the invention provides apparatus for creating a moving lighting effect, said apparatus preferably comprising: a surface that is arranged, in use, to controllably assume a predetermined shape that varies predictably with time; at least one light source arranged, in use, to direct light towards said surface; whereby said moving lighting effect is created in light from said light source whose subsequent path has been modified by said surface.

The plurality of actuators, which preferably cause the surface to assume the predetermined shape that varies predictably with time, can be mechanical, electro- mechanical, pneumatic, magnetic or electrostatic in nature, or can comprise any type of actuator. Examples include actuators comprising solenoids, speaker coils and muscle wire (Nitinol). The actuators can be connected to the surface via a resilient member such as a rubber pad, foam backing or spring.

In embodiments utilising magnetic or electrostatic actuators, one convenient configuration is to impregnate the surface membrane with a material having the desired electrical or magnetic properties. The surface can thereafter be attracted or repelled towards an actuator in order to deform the surface in the direction perpendicular to its neutral plane.

For actuators employing a magnetic effect, the surface can be made from a silicone sheet impregnated with ferrous or magnetic material. Each of the actuators can be provided by a selectively actuatable electromagnet which is capable of attracting or repelling the surface at its localised position. The plurality of such actuators working together can be used to create a desired predetermined shape on the surface.

Electrostatic actuation can be achieved by applying electric potentials to the surface and to various pads located adjacent to the surface. When the pad and the surface are at the same high voltage, a force of repulsion will be generated, an opposite charge on the actuator pad to the charge on the surface will cause a force of attraction to be generated. A dielectric substance is preferably positioned between the surface and the actuator pads to prevent conduction of charge between them.

Once charged, the actuator pads or surface hold their charge for a certain amount of time. There is therefore no urgent requirement to continually apply a potential difference to each actuator as the device is used. As such, each actuator can be given its charge in a time slot, with the time slots arranged in series and this allows a smaller number of potential difference generators to be used. This reduces the complexity and assembly cost of the apparatus. To achieve this, it is preferable that the pads have a suitable capacitance. The performance is a balance between the capacity (how long the pads can hold the charge) and the associated charging time for each cycle.

As mentioned, this type of approach lends itself to multiplexing, i.e. rather than having one drive unit per actuator, a number of actuators are operated by one drive unit, thus reducing the cost. This is possible by either using the capacitance of the pads, or, by using electronics and the drivers together so the drivers set a value and the electronics continue to apply that value until it is changed by the driver. In the latter, this multiplexing technique is applicable also to the other types of actuation such as mechanical or magnetic.

The manipulable surface is preferably comprised of a flexible membrane, for example made of a polymeric material such as silicone. The membrane is preferably sealed to a support structure around its periphery and can be initially biased in a particular direction perpendicular to its neutral plane. Such biasing can be achieved by means of positive or negative fluid pressure or by applying a magnetic or electric field to a membrane having a suitably impregnated material.

One advantage of the present invention is that the neutral plane of the surface does not need to be located in a horizontal plane (as it would need to be if the surface was comprised of a water surface). The membrane can therefore be held in any orientation and the same glistening effect will be achieved. Furthermore, the neutral plane does not need to be flat and can be curved. Thus, the image of the glistening pattern can be projected over a wide area if desired.

The apparatus can be provided without its own source of light in which case the user need only appropriately position the apparatus to receive incoming sunlight or other light from an external light source. It is, however, possible for the apparatus to comprise its own light source. Such light source is preferably mounted in the same casing as the manipulable surface and any actuators and controller.

It has been found that collimated light (in which all the beams are substantially parallel) provides an optimum glistening effect. Such can be obtained by using appropriate lenses or reflectors, or by positioning the light source at some distance from the surface. Light emitting diodes are particularly convenient sources of light because they can easily be placed on printed circuit boards. More than one light source can be used. Preferably, the light incident on the surface is incident at a single angle. This avoids blurring the image and also serves to give a brighter overall image.

The light source(s) are preferably located close to the surface in order to obtain a compact product.

In addition to, or as an alternative to, using a plurality of light sources, a light source can be moved in space such that the light emanating from it scans over the manipulable surface. In this way, collimated light (which necessarily has a low cone angle) can be emitted from a reduced number of light sources yet the whole area of the manipulable surface can be utilised. When the light which makes up the moving lighting effect is obtained by refraction at the surface, there is a need to mount the light source(s) and any actuators on the same side of the surface. In such a case, a substrate can be provided for supporting the plurality of light sources and also for supporting the plurality of actuators. The light sources and actuators can be provided in a matrix such that each actuator is surrounded by a light and each light is surrounded by an actuator. Alternatively or additionally, the actuators can have light sources located in their structure.

In one embodiment of the invention, the moving lighting effect achieved can be influenced by the user, either by allowing the user to select a particular lighting effect or by using sensors to monitor conditions of the environment and modifying the lighting effect in accordance with the sensed values.

For example, a movement sensor can be used to detect the movement of a user's hand and the lighting effect can be modified in accordance with the signal from the movement sensor such so as to simulate the effect on a notional water surface of the movement of the user's hand thorough the surface.

In a fifth aspect of the invention, there is provided a moving surface for use in an apparatus which creates a moving lighting effect, said moving surface preferably comprising: a layer of flexible polymeric material; means acting on said layer of flexible polymeric material so as to change its shape with time such that said moving lighting effect can be created in light whose subsequent path is modified by said surface.

The layer is preferably silicone. The silicone can have a reflective surface finish or can be coated with a reflective coating. To give extra elasticity, the silicone can be mixed with latex or other elastic material.

A sixth aspect of the invention provides a membrane for use in an apparatus which creates a moving lighting effect, said membrane preferably being made from a flexible polymeric material and comprising a metal additive which allows said membrane to retain at least temporarily, a charge applied thereto.

The metal additive can be metal particles applied to the body of the silicone during manufacture or it can be a metal coating.

A seventh aspect of the invention provides the use of a membrane manipulable by a plurality of actuators to simulate the surface of water so as to provide a moving lighting effect.

A eighth aspect of the invention provides the use of a membrane and at least one actuator whereby said actuator applies controlled distortions to said membrane such that light modified by said membrane is endowed with a moving lighting effect that resembles the glistening obtained when light shines on water having gentle waves moving thereacross.

The invention will now be further described by way of non-limitative example only with reference to the accompanying drawings, in which:Figure 1 is a cross-sectional view that explains the refractive and reflective glistening modes; Figure 2 is a photograph of a refractive glistening effect; Figure 3 is a photograph of a reflective glistening effect; Figure 4 is a schematic partial side elevation and cross-section of a first embodiment of the invention; Figure 5 is a schematic partial side elevation and cross-section of a second embodiment of the invention; Figure 6 is a schematic partial side elevation and cross-section of a third embodiment of the invention; Figure 7 is a perspective view of a fourth embodiment of the invention with the membrane being partially cut away to show the actuators; Figure 8 is a closer perspective view of one of the components shown in Figure 7, again with the membrane partially cut away; Figure 9 is a perspective view of a fifth embodiment of the invention, with the membrane and support substrate partially cut away; Figure 10 is a perspective view of a sixth embodiment of the invention, with the membrane, support substrate and upstanding walls partially cut away; and Figure 11 is a perspective view of a seventh embodiment of the invention, with the membrane, support substrate and upstanding walls partially cut away, similar to Figure 10, but with an integral light source.

The present invention has been directed towards the provision of a primarily domestic lighting product that can create a glistening effect and can project the changing reflections or refractions onto a ceiling, wall or other projection plane. The invention provides a more controllable and tolerant system than has been disclosed in the prior art and has application in the construction of illumination systems for a diverse range of applications, for example hotel or office receptions, gardens, stage productions and domestic lighting.

To assist in the understanding of the invention, a description of the glistening process is given below.

Figure 1 shows a cross-sectional view of a body of water (1) contained in a tank having a bottom surface (2) and a side surface (3). The water has a free surface (4) upon which gentle waves propagate. The key to understanding the glistening phenomenon is the realisation that the gentle waves act as lenses that focus and disperse incoming light beams. The glistening phenomenon occurs in one of two ways.

Refraction Consider light beams (5) which are all initially parallel and impinge upon the surface (4) of the water (1). As the light beams interact with the surface, their angle changes in accordance with Snell's Law. In particular, the angle of the light beam moves closer to a line that is normal to the surface at the point at which the light beam interacts with the surface. As can be seen in Figure 1, the convex surface of a peak of a wave serves to focus light beams to create a bright spot on the bottom (2) of the tank. Conversely, the concave parts of the wave cause the light beams to spread out, giving darker areas. The resulting pattern is commonly observed on the bottom surface of shallow areas of water, such as swimming pools. A photograph of a typical refraction glistening pattern is shown in Figure 2.

Reflection Light is reflected at the same angle to the normal at which it is incident. The troughs of the waves serve to focus light beams and the peaks of the waves serve to disperse light beams, creating similar light and dark zones on the wall (3) as were created by refraction on the bottom of the tank (2). An example of a reflected glistening pattern on the side of a boat is shown in Figure 3.

In order to provide an attractive moving lighting effect, but without the inconvenience of using actual water, the present invention is based in part upon the use of a non-liquid substitute for the water, such as a solid or a gel. In particular, a flexible membrane can be used to simulate the water surface. The flexible membrane is manipulated so as to deform into a predetermined shape having the convex and concave portions that give the light and dark areas associated with the glistening effect.

The convex and concave portions are then moved over the surface of the membrane to simulate the movement of waves across the surface of water. When light is incident on the membrane surface, the membrane's effect on that light is reminiscent of the glistening effect achieved with actual water.

Embodiments of the invention therefore comprise several components: A flexible membrane. This is preferably soft and compliant with appropriate properties to act as a lens. If the lighting effect is to be achieved by reflection, the membrane needs to be at least partially reflective. If the lighting effect is to be achieved using refraction, the membrane needs to be at least partially transparent. It is preferable, although not essential, that the membrane is elastic or elastomeric. A suitable material for the flexible membrane is a polymeric material, which material may also be a synthetic material, such as silicone.

Actuation. Means are provided to apply a positive or negative movement to the membrane. The actuation can take any suitable form and particularly preferred is a plurality of actuators that form a matrix and enable a variable contour to be applied to the membrane.

Control. Control signals are supplied to the actuation means in order to determine the shape of the membrane at any particular time.

The use of a flexible membrane removes the need for water, thus removing the risk of spillage, leakage and splashing, particularly onto containing surfaces that would affect the light, leaving droplets or condensation on an internal surface. There are however more significant benefits such as removing the need for the surface to be planar (i.e. enabling it to be curved) or to be kept horizontal. The surface also becomes more tolerant to its environment and is less likely to be affected by the vibrations of someone walking past and can even be used as a simple reflector when the glistening effect is switched off'.

The associated matrix-based actuation gives further advantages over, say, applying vibrations or waves into the membrane. Using numerous and variable actuation points it is possible to create a large number of lens shapes and forms, not just those required for glistening. Further it is possible to optimise the lens, creating only the part of the waves that actually focus the light (removing the peaks in the case of reflection or reducing their height to reduce shadowing or clipping if the light source is at an angle) or adjusting for a surface that is curved.

A processor based control system offers the ability to create optimised glistening shapes as described above, but is also an ideal interface for potential inputs, for example reacting to non-contact movements or sound etc. However a key benefit is that of control. Natural processes are difficult to control, both in the initial input and in feedback control. Specifically it is a matter of trial and error to create a good effect based on the variables of a water tank. In addition, it is difficult to monitor the effect and to know when the energy levels become too high and thus the effect is lost. With a fully controlled system such as described here, this problem is reduced.

Figure 4 shows a first embodiment of the invention. A substrate (10), which is rectangular in plan-view, has upstanding walls (12) which define the periphery of an active area. Supported by the upstanding walls (12) is a flexible membrane (14), preferably made of a synthetic polymeric material such as silicone. The membrane (14) is also connected at various points on its underside to substrate (10) via a plurality of actuators (16), only eight of which are visible in the section through the substrate (10), walls (12) and membrane (14). The actuators serve to create forces that are perpendicular to the neutral plane of the membrane (14). The neutral plane of the membrane is shown in Figure 4 referenced as (18).

The actuators (16) preferably form a matrix spanning the entire area underneath the membrane (14). For example, there may be 64 actuators arranged in an 8 by 8 rectangular matrix. Other numbers of actuators can be used according to the circumstances.

Each actuator is connected via an electrical control wire (20) to a controller (22), which controller may be a microprocessor. Although one wire (20) is shown per actuator (16), multiplexing may enable other, simpler wiring arrangements to be utilised. The controller (22) provides the necessary actuation signals, via communication wires (20), to the actuators (16). How these actuation signals are generated will be described later.

Light sources (24, 26) are located so as to direct light towards the membrane (14) at an oblique angle. Light incident on the membrane is reflected therefrom and, as shown schematically, impinges on the viewing surface (28), which could be a wall or ceiling of a room, or a screen provided as part of the apparatus.

In use, the controller (22) provides signals to the actuators (16) which cause the membrane to move in directions perpendicular to its neutral plane (18). Such movement of the membrane endows the reflected light from the light sources (24, 26) with a pattern that is projected on to viewing surface (28).

To achieve a glistening effect on the viewing surface (28), the actuators (16) can receive actuation signals that cause them to move the membrane (14) in a way which simulates the motion of gentle waves moving across the surface of water.

Figure 5 shows a second embodiment of the invention which works in a refractive mode.

The membrane (14) is made of transparent silicone and a plurality of LED light sources (32) are mounted on substrate (10). The light sources (32) direct light upwards (as drawn in Figure 5) through the membrane (14), where they are refracted in order to provide a lighting effect on viewing surface (28). For reasons of clarity, schematic rays of light have been omitted. The light sources (32) are arranged in a matrix that complements the matrix of actuator (16). For example, when the actuators (16) are arranged in an 8 by 8 square matrix, the light sources can be arranged in a 7 by 7 square matrix, with the light sources occupying the spaces in between adjacent actuators.

Figure 6 shows a third embodiment of the invention in which a transparent bowl (34) surrounds the space above the membrane (14). Near the rim of the bowl are located light sources (36) which direct light towards the membrane (14). Light is reflected from membrane (14) to produce a moving light effect on viewing plane (28). For reasons of clarity, schematic rays of light have been omitted.

The bowl (34) can be provided with a movement sensor (38) which senses the movement of an object in the vicinity of the inside of the bowl. For example, movement sensor (38) can sense the user placing his hand inside the bowl. This generates a signal which is provided to the controller (22) and the controller (22) can in turn modify the actuation signals provided to actuators (16) so as to provide a pattern on the membrane (14) surface that simulates, for example, the effect of the user putting his hand in a bowl of water. In this way, the moving lighting effect can be made to act in accordance with inputs received from the environment.

Alternatively, a further bowl and sensor (not shown) may be provided separately of the illuminated, membrane-containing bowl (34), to act as a "virtual water-filled bowl" into which a user can dip his or her hand to influence the light pattern produced, without the user's hand casting ashadow in the projected pattern. The bowl and sensor can be used with any of the embodiments of the invention The actuators (16) may take any of various forms, for example mechanical, electromagnetic and electrostatic actuators.

Mechanical actuators typically take the form of linear devices such as solenoids, speaker coils or a mesh of so-called "muscle wire". Consider the latter - the muscle wires connect to the membrane. The system may be biased; the membrane (14) which is sealed to upstanding wall (12) may have a fluid pressure, such as is provided by air pressure, in the space underneath the membrane (14) and above the substrate (10). Pulling down in one area causes an opposite reaction elsewhere and generates a return force. Alternatively or additionally the muscle wires can act against a matrix of resilient members such as springs. In either instance the application of a current, and therefore a heating effect, to the wire causes it to contract proportionally. Thus the varying outputs from the controller act to adjust the movement/force of the actuator. Mechanical actuators offer the potential for significant movement and force and the relationships tend to be linear or at least follow simple proportionality and are thus relatively easy to control. However, they offer considerable disadvantages with respect to size requirements, complexity and generally are costly.

Electro-magnetic solutions offer small and cost effective solutions but the forces and movement are smaller and the attraction is based upon the inverse square law, making the system sensitive to small changes.

Rather than physically adjusting the membrane position, electro-magnets can be used to apply the necessary force to the membrane. Clearly in this case the membrane must be able to be influenced by a magnet, for example it can be a magnetic material loaded or metal loaded rubber or silicone. Another option is to add a matrix of permanent magnets to the membrane. A further option is to attract the membrane by using one large permanent magnet, then variably use the actuator electro-magnets to overcome this attraction. There are thus two scenarios based upon (1) a neutral plane solution and (2) a biased solution.

A neutral plane is one where the membrane (14) operates around a nominal datum referenced (18) in Figures 4 to 6. In this case the membrane must be poled, and the actuators work by applying different values of the opposite or same pole to attract or repel. Although it is possible to create a poled membrane, the thin properties of the material and the nature of magnetism result in a short life expectancy. In this scenario it is preferred to include a matrix of permanent magnets, although this is still not ideal as the repelling force can act to turn the magnet and thus twist! distort the membrane.

A biased system has actuators that act only to attract the membrane, the peaks of the waves are created by having an opposing force, typically by having the system pressurised. Pulling the membrane down causes the rest of the membrane to lift to compensate. When a number of points are pulled down the wave shapes are formed.

Clearly this technique is not as controllable as the neutral plane approach. In this case the membrane can be ferrous (silicone loaded with metal fragments) to give the necessary attraction.

The use of electrostatics can further reduce the potential cost and complexity.

Working in a similar way to the magnetic solution, it uses the attractive and repulsive forces of high voltages (typically up to 10kV is required to generate the movement).

In this case a plurality of electrical pads form the actuators and are variably charged.

The membrane is also charged. An opposite charge will attract the membrane to the pad; a like charge will repel it. The use of high voltages makes it preferable to use a dielectric to stop the breakdown or shorting out between the membrane and the pads.

The membrane can typically be made with a metal loaded silicone, which offers the ability to conduct electricity. This is ideal for creating a high voltage charge. The force generated is relative to the distance and voltage differential. The latter can be used to advantage; by having a relatively high charge on the membrane, the associated charge on the pad can be relatively low, which reduces the equipment cost in switching high voltages.

Whereas the magnetic solutions require a plurality of electro-magnets, the electrostatic system requires only pads, which can be simply and cheaply created, by traditional printed circuit board techniques for example. Further because a plate can be charged it is possible to multiplex with this approach. Thus, rather than requiring a permanent electrical feed to each actuator (as when driving an electro-magnetic coil) it is possible to have a single or reduced number of potential difference generators that rapidly switch between each pad adjusting the charge as required.

This significantly reduces the assembly cost.

The electrostatic technique can use either the neutral plane approach or the biased system. It has the advantage that the membrane is actively charged so its value can be changed and not significantly decay over time. A potential problem with such applications is that the charge can migrate during use. This can be addressed by zoning, having a number of areas of the sheet that are charged (the same but) independently.

The actuators work with the membrane and the two must complement one another. An example of this is in the flexibility of the membrane. Consider a fine matrix of actuators working on a neutral plane scenario. The high density of actuators means the wave shapes can be accurately defined and the neutral plane technique means the shape can be defined for both the peak and the trough of the wave. Such a membrane is required to accurately track the changes of the actuators and should be light and highly flexible. Now consider reducing the number of actuators per unit area (thus reducing the costs) and thus reducing the resolution of the wave definition. The membrane is now required to fill in the gaps' to form a natural curve between actuators. This can be partly achieved by using a biased system. Alternatively the material properties of the membrane can be changed, reducing how flexible it is and thus forming natural curves and contours. In this situation the material properties change with respect to resolution and as the resolution reduces the membrane must approximate the wave shape.

The membrane must be able to form the shapes and folds of waves and where waves meet waves and still keep good optical properties. It should not crease and should have a minimal surface tension' so the force to displace say one small wave is similar to that to displace many large ones. For reflecting embodiments, it needs to have good reflective properties, probably but not necessarily the more reflective the better. (If the surface is highly reflective then all the light will reflect off it, including the unfocussed, polluting light). The nature of the material is clearly different if the light source is below the surface and will refract through. In tests a highly suitable material has been found to be silicone, which can also be loaded with the appropriate materials for the different actuator techniques. Although not truly elastic it can be highly flexible and this can be adjusted easily with changes to the thickness and the Shore hardness. It can also be processed to have varying levels of reflection and is available transparent or opaque.

For a mechanical actuator system the membrane properties are strictly dependant upon the resolution and the optical requirements. It can be either neutral plane or biased.

In the case of a magnetic solution the membrane is preferably either loaded with a ferrous material or includes a matrix of permanent magnets. As discussed previously this process favours a biased solution.

In the case of electrostatics, the membrane must preferably be capable of carrying a high charge. It may be advantageous for this charge to be contained in a number of zones to reduce charge migration. The material is loaded with metal, to give the ability to conduct some charge. This can be either be a biased or a neutral plane solution. However, in the case of the latter the nature of electrostatic attraction needs to be considered. The force applied to the membrane is proportional to the inverse square of the distance. This force is also of course only applied when there is a charge, so the membrane is not self-supporting. Therefore in the case of a high resolution solution (very flexible membrane) it may be advantageous to add a supportive structure, such as foam. Depending upon the position of the neutral plane this can give increasing resistance to movement as the membrane is attracted and it can support the membrane when there is no charge. It also tends to have a consistent resistive force regardless of how many waves are formed (in a biased system, the more troughs the greater the force required to create another) .

An alternative to loading the material with metal is to provide the silicone with a transparent conductive surface. This means the silicone can be transparent and work in an electrostatic mode, thus giving the option of illuminating the membrane from below.

Creating the control signals for the actuators The controller (22) provides control signals to the actuators (16). Such control signals can be obtained by mathematically approximating water waves as sinusoids. The control model can be an accurate mathematical representation of the movement of a surface, but can also be more simplistic using more standard wave forms to generate a similar effect. The curve describing the waves can be a trochoidal-shaped wave or a sinusoidal wave, for example. The trochoidal curve has been described in the literature as one of the best representations of the sea wave shape. The sinusoidal curve can be used as a simplified version of the wave movement and is good enough to be used in the model. Both kind of waves are good representations of wave motion and will focus collimated light from a vertical direction on a level bottom.

The mathematical model requires inputs, for example the fluid characteristics (such as viscosity) or wave characteristics (such as wave type, described by an algoritimi). It then calculates the wave function by entering key attributes that change with respect to time, e.g. wave amplitude or direction. Using this and the principle of superposition a virtual surface is created. Iterative calculations enable this surface to change with time, as an animation. For each sample period in this animation the model creates a corresponding output to each actuator which defines the positive (or negative) force applied to the membrane surface.

These outputs can be created and recorded for use in the apparatus.

Recording of a program reduces the processing power required, which it should be understood can be significant if the actuator resolution is fine (many actuators per unit area).

Clearly options in increasing the sophistication of the product exist, with increasing demand on memory or processing power.

For example, a number of recorded programs can be stored and switched between, or run in parallel to create superimposed effects.

Optionally it is possible to apply simple processing in real time. For example the product can store the pre-calculated wave functions, but inputs to this (e.g. amplitude) can be changed. This changes the surface but only requires a simple magnification factor to be calculated. Further these can be initiated or affected by inputs from the user or act to give the surface more of a random action. Figure 4 shows an input device (30) which allows the user to provide inputs to the controller (22).

With greater processing to the point of calculating the wave functions in real time, it becomes possible to have actual user inputs, with the appropriate outputs calculated and this imitated in the membrane surface. Thus, a movement sensor can create an input signal relative to the movement of a hand, so a user can stroke an empty bowl' and the light would glisten as if the bowl contained water being disturbed. Figure 6 shows such an input device (38) which measures the movement of a user's hand. An accelerometer can detect movement of a hand held controller; say a ball, which can again respond accordingly to the movement. More simply the user can set certain parameters to match the mood, such as the maximum speed of a pattern, or the system can be adjusted to reduce clipping from the proposed light source if it were at an oblique angle.

It should be clear that in using a calculated mathematical model, with inputs from an external source the system becomes isolated from the environment, and thus not sensitive to it, but can selectively respond to that environment.

These outputs from the model, be them recorded or created in real-time are fed to the matrix of actuators (16). Typically the surface would move a maximum of a few millimetres, but this is dependant upon the application parameters such as size and membrane attributes.

Figure 7 shows a fourth embodiment of the invention. In this embodiment, the light source (24) is disposed separately from a "glistening pad" having a membrane (14) across its top surface. A screen (28) is disposed the other side of the glistening pad from the light source such that rays of light from the light source (24) interact with the membrane (14) and reflect onto the screen (28) so as to provide the moving lighting effect, such as a glistening pattern, thereon.

The glistening pad of this embodiment is shown more closely in Figure 8.

The side walls (12) of the pad enclose 64 regularly spaced voice coils (16). Each voice coil is a simple kind of solenoid, similar to the coils used in loudspeakers for acoustic applications. When an analogue electric signal is applied to the voice coil (16), the centre portion moves either upwardly or downwardly in accordance with the voltage of the signal applied. As will be appreciated from Figures 7 and 8, analogue signals can be separately provided to each voice coil (16) so as to create deformations in the membrane (14). As with the first embodiment, these deformations modify the path of light beams issuing from light source (24) so as to create a lighting effect on the screen.

It will be appreciated that in this embodiment the light source (24) is separate from the means for modifying the light beams. The light source can in principle be combined with the membrane surface to provide a single unit.

Figure 9 shows a fifth embodiment of the invention which, as with the second embodiment of Figure 5, uses refraction to provide the necessary moving lighting effect.

In this embodiment, the electrostatic principle described above is used to create deformations in the surface of membrane (14). A matrix of electrically chargeable pads (40) are located on a support substrate. The membrane (14) is impregnated with an electrically chargeable material (such as a metallic material) and is separated from the pads (40) by a layer of dielectric (not shown). Interspersed with the matrix of pads (40) is a matrix of holes (42) through the substrate. These holes are an alternative to the LEDs (32) shown in Figure 5. A parabolic reflector (44) is disposed underneath the substrate and a light source (not shown) is placed at the focal point of this reflector. Light emitted from this light source is reflected by the reflector (44) and thereafter travels in a substantially collimated upward direction through the holes (42), where is it refracted by the membrane (14). Due to the deformed shape of the membrane, a moving lighting effect is created on any surface upon which the light impinges, such as a ceiling or a horizontally disposed viewing surface (not shown in Figure 9).

This embodiment allows a single light source to be used to illuminate most of the area of the membrane (14).

Figure 10 shows a sixth embodiment of the invention. This embodiment is similar to the fourth embodiment of Figures 7 and 8 in which a separately disposed glistening pad is provided. In this sixth embodiment, however, the neutral plane (18) of the glistening pad is curved in one direction so as to conform to part of the surface of a cylinder. The provision of a curved neutral plane for the membrane (14) means that light reflected from the membrane spans a wider area such that the effect is magnified compared to the case when the neutral plane is planar. Although Figure shows the case when the neutral plane is curved in only one direction, the neutral plane can be curved in more than one direction, such as to conform to part of the surface of a sphere, for example.

Figure 11 shows a seventh embodiment of the invention which, like the sixth embodiment, has a membrane (14) with a curved neutral plane. As with the fourth and sixth embodiments, the actuators are provided by voice coils (16). As will be appreciated from Figure 11, two of the upstanding walls (12) are extended in a vertical direction and have mounted thereon light sources (36). Light from the light sources (36) is reflected by the membrane (14) so as to provide the moving lighting effect on a suitably positioned viewing surface.

Various modifications can be made to this embodiment, for example, the membrane (14) and supporting substrate (10) can be made circular and the light source (36) can be provided completely around the diameter of the circular membrane, as was the case with the third embodiment of Figure 6.

Any of the actuation possibilities discussed herein can be used to replace the disclosed actuators in the above embodiments. For example, the voice coils illustrated in Figures 7, 8, 10 and 11 can be replaced by actuators working on the magnetic or electrostatic principles discussed above.

It has already been stated that it can be advantageous to control the nature of the light source, specifically the divergence of the light beam. Other aspects may also be adjusted to alter the reflections, including the colour of the light and the position of the light, for example by using coloured lenses, filters or bulbs/LEDs.

Further it may be beneficial to link attributes of the light and the surface together through the controller. For example, if the position of the light source is known to the controller (by user input, simple mechanical position or remote sensing such as Radio Frequency) then it can be made to adjust the function of the membrane accordingly. In this case if the light was at an oblique angle (low to the horizon) then the wave form could be adjusted to reduce the clipping effect of the top of the waves.

It follows that similar benefits can be gained from understanding the position of the screen. If for example the screen was a long distance away, then the waves could have a shallow form, giving a longer focal length.

It may be advantageous to have a reflective or semi-reflective base, below the membrane surface. This can be provided by the inner membrane surface or by material around the actuators. This enables secondary effects to be created in the case of light that is refracted into the membrane rather than reflected.

For simplicity, wiring layouts and controllers are not shown in any of Figures 7 to 11.

Claims (59)

1. A method of creating a moving lighting effect using light incident on a non-liquid surface, said method comprising: manipulating said surface when light is incident thereon by using a plurality of actuators; whereby the subsequent path of said incident light is modified by said surface so as to create said moving lighting effect.

2. A method of creating a moving lighting effect using light incident on a surface, said method comprising: manipulating said surface when light is incident thereon, said manipulation being controlled such as to cause said surface to assume a predetermined shape that varies predictably with time; whereby the subsequent path of said incident light is modified by said surface so as to create said moving lighting effect.

3. A method according to claim 2, wherein said surface is manipulated by using a plurality of actuators.

4. A method according to claim 1 or 3, wherein said plurality of actuators span substantially the whole of an area of said surface over which light is incident, in use.

5. A method according to claim 1, 3 or 4, wherein said plurality of actuators are arranged in a regular matrix.

6. A method according to any one of claims 1, 3, 4 or 5, further comprising generating actuating signals in a controller and sending an actuating signal to each respective one of said plurality of actuators so as to modif' the displacement of said surface at a point adjacent each respective one of said plurality of actuators.

7. A method according to any one of the preceding claims, further comprising projecting said moving lighting effect so as to magnify it.

8. A method according to claim 7, wherein said moving lighting effect is projected onto a generally planar viewing surface.

9. A method according to any one of the preceding claims, wherein said moving lighting effect is created in light that is reflected from said surface.

10. A method according to any one of the preceding claims, wherein said surface is at least partially transparent and said moving lighting effect is created in light that is refracted by said surface.

11. A method according to any one of the preceding claims, wherein said surface is manipulated so that it assumes a shape based on a sinusoid, or a linear superposition of sinusoids.

12 A method according to any one of the preceding claims, wherein said moving lighting effect simulates the glistening obtained when light shines on water having gentle waves moving thereacross.

13. A method according to any one of the preceding claims, wherein said surface is the surface of a flexible membrane.

14. A method according to any one of the preceding claims, further comprising directing light onto said surface and modifying the path of said light to create said moving lighting effect.

15. Apparatus for creating a moving lighting effect, said apparatus comprising: a surface; a plurality of actuators which act to manipulate the shape of said surface; a controller arranged, in use, to provide signals to said actuators so as to cause said surface to assume a shape that varies with time such that said moving lighting effect is created in light whose subsequent path has been modified by said surface.

16. Apparatus according to claim 15, further comprising at least one light source arranged, in use, to direct light towards said surface.

17. Apparatus for creating a moving lighting effect, said apparatus comprising: a surface that is arranged, in use, to controllably assume a predetermined shape that varies predictably with time; at least one light source arranged, in use, to direct light towards said surface; whereby said moving lighting effect is created in light from said light source whose subsequent path has been modified by said surface.

18. Apparatus according to claim 17, further comprising a plurality of actuators which act to manipulate the shape of said surface so as to cause said surface to assume said predetermined shape that varies predictably with time.

19. Apparatus according to claim 15 or 18, wherein said plurality of actuators are mechanical or electro-mechanjcal actuators.

20. Apparatus according to claim 19, wherein said plurality of actuators are solenoids.

21. Apparatus according to claim 19, wherein said plurality of actuators are speaker coils.

22. Apparatus according to claim 19, wherein each of said plurality of actuators comprises muscle wire that contracts upon the provision of an electrical current that locally heats said wire.

23. Apparatus according to any one of claims 19 to 22, wherein each of said actuators is connected to said surface via a resilient member.

24. Apparatus according to claim 23, wherein said resilient member is a spring.

25. Apparatus according to claim 15 or 18, wherein said surface is impregnated with a ferrous or magnetic material and each of said plurality of actuators comprises a selectively actuatable magnet capable of attracting or repelling said surface.

26. Apparatus according to claim 15 or 18, wherein said surface is impregnated with a material that can retain, at least temporarily, an electrical charge.

27. Apparatus according to claim 26, further comprising a potential difference generator for applying a predetermined voltage to said surface so as to charge it to a predetermined potential.

28. Apparatus according to claim 26 or 27, wherein each of said plurality of actuators comprises an area of electrically chargeable material adjacent to said surface, but separated therefrom via a dielectric material, said area of electrically chargeable material being capable of being charged to a predetermined potential so as to attract or repel said surface.

29. Apparatus according to any one of claims 26 to 28, wherein the or a controller is arranged to apply a charge to each actuator in a predetermined time slot such that changes are applied to each respective actuator serially in time.

30. Apparatus according to claim 29, wherein said charge is provided to each actuator by a potential difference generator and there are fewer potential difference generators than there are actuators.

31. Apparatus according to any one of claims 15 to 30, wherein said surface is provided by a flexible membrane.

32. Apparatus according to claim 31, wherein said membrane is sealed to a support structure around its periphery.

33. Apparatus according to claim 31 or 32, wherein said membrane is initially biased so as to be deflected in a particular direction and the shape of said membrane is changed by deflecting points of said membrane in directions opposite to said particular direction.

34. Apparatus according to any one of claims 15 to 33, wherein said surface has a curved neutral plane.

35. Apparatus according to any one of claims 15 to 34, further comprising a support foam attached to said surface for supporting said surface.

36. Apparatus according to claim 16 or 17, or any claim dependent thereon, wherein the light from said light source is substantially collimated.

37. Apparatus according to claim 16, 17 or 36, or any claim dependent thereon, wherein said at least one light source is a light emitting diode.

38. Apparatus according to claim 16, 17, 36 or 37, or any claim dependent thereon, wherein there are provided a plurality of light sources arranged to direct light towards said surface from different positions.

39. Apparatus according to claim 38, wherein said plurality of light sources are provided to be underneath said surface in use and said light is modified by said surface by refracting therethrough.

40. Apparatus according to claim 39, further comprising a supporting substrate for supporting said plurality of light sources and also for supporting the or a plurality of actuators.

41. Apparatus according to any one of claims 15 to 40, further comprising an input device which allows a user to influence the obtained moving lighting effect.

42. Apparatus according to claim 41, wherein said input device is a selector for allowing a user to select at least one of a plurality of predetermined moving lighting effects.

43. Apparatus according to claim 41, wherein said input device is a sensor that senses a parameter of its environment and supplies a sensed value to the or a controller so that the moving lighting effect can be adjusted in accordance with said sensed value.

44. Apparatus according to claim 43, wherein said input device is an accelerometer having a size and configuration that allows it to be held in a user's hand, such that the moving lighting effect can be made to appear to react to movement of the user's hand.

45. Apparatus according to claim 43, wherein said input device is a sound sensor such that the moving lighting effect can be adjusted in accordance with sounds in the environment of the apparatus.

46. Apparatus according to claim 43, wherein said input device is a movement sensor such that the moving lighting effect can be influenced in accordance with movement in the environment of the apparatus.

47. A moving surface for use in an apparatus which creates a moving lighting effect, said moving surface comprising: a layer of flexible polymeric material; means acting on said layer of material so as to change its shape with time such that said moving lighting effect can be created in light whose subsequent path is modified by said surface.

48. A moving surface according to claim 47, wherein said flexible polymeric material is elastomeric.

49. A moving surface according to claim 47 or 48, wherein said flexible polymeric material is a synthetic material.

50. A moving surface according to claim 47, 48 or 49, wherein said flexible polymeric material comprises silicone.

51. A moving surface according to any one of claims 47 to 50, wherein said layer of flexible material is coated with a reflective coating.

52. A moving surface according to any one of claims 47 to 51, wherein said means acting on said layer of flexible material comprises a plurality of actuators.

53. A membrane for use in an apparatus which creates a moving lighting effect, said membrane being made from a flexible polymeric material and comprising a metal additive which allows said membrane to retain, at least temporarily, a charge applied thereto.

54. Use of a membrane manipulable by a plurality of actuators to simulate the surface of water so as to provide a moving lighting effect.

55. Use of a membrane and at least one actuator whereby said actuator applies controlled distortions to said membrane such that light modified by said membrane is endowed with a moving lighting effect that resembles the glistening obtained when light shines on water having gentle waves moving thereacross.

56. A method of creating a moving lighting effect substantially as hereinbefore described with reference to any one of Figures 4 to 6 of the accompanying drawings.

57. Apparatus for creating a moving lighting effect, constructed and arranged substantially as hereinbefore described, or with reference to any one of Figures 4 to 6 of the accompanying drawings.

58. A moving surface for use in an apparatus which creates a moving lighting effect, constructed and arranged substantially hereinbefore described, or with reference to any one of Figures 4 to 6 of the accompanying drawings.

59. A membrane for use in an apparatus which creates a moving lighting effect, constructed and arranged substantially hereinbefore described, or with reference to any one of Figures 4 to 6 of the accompanying drawings.