ACCUMULATING OPTICAL ELEMENT

Abstract

1 8 The invention relates to an optical system, comprising at least one optical element which comprises a cover having a first surface and a second surface, a support, and a means. The cover is orientated with the first surface directed towards the support, a part of the first surface is attached to the support. A spatial arrangement of the cover as seen in a cross section of the cover defines a cover contour profile and the means is arranged to move the cover from a first cover contour profile to a fiirther cover contour profile which is different from the first cover contour profile. According to the invention, the optical system fiirther comprising an accumulator that accumulates light from a source of light, such as a source of diffused light. The invention also relates to the use of such a system.

Description

The current application relates to an optical element comprising, a cover having a rst surface and a second surface, a support, and ameans. The cover is orientated with the rst surface directed towards the support, a part ofthe rst surface is attached to the support, a spatial arrangement ofthe cover as seen in a cross section ofthe cover denes a cover contour prole, and the means is arranged to move the cover from a rst cover contour prole to a further cover contour prole which is different from the rst cover contour prole. An optical element is known from e.g.WO 2021 / 032752 AI andWO 2018 / 228671 AI. This document discloses optical devices ofspecic interest. The working principle is thatwhen a cover is provided that has some desired optical behaviour, e.g. reecting light, transmitting only some light, etc. the interaction ofincident light can be changed by changing the cover contour prole. To facilitate the cover changing shape to facilitate changing the optical behaviour ofthe optical device, the cover is made relatively thin, in terms ofWO 2021 / 032752 AI 2-dimensional. As an example, a single graphene layer cover is presented, with a coating on top to obtain desirable optical behaviour. Since the optical device is very small, they can be used to act like a pixel in a larger collection of similar devices. Control of scattering, reection and / or interference behaviour can be used to turn a pixel on or offand / or vary its colour. This way, images can be generated and / or manipulated. Several principles ofoperation are available with such optical devices.A rst operational principle is shown in gures IA 1C, which correspond to gures 9 II ofWO 2021 / 032752 AI. These gures show respectively an optical device with a at cover, a convex cover, and a concave cover. Light incident on the at cover (g. 1A) is reected as ifhitting a smooth and straight surface, i.e. parallel incident rays remain parallel after reection. As such, specular reection takes place at the cover. In the convex and concave positions ofthe cover, parallel incident rays are no longer parallel after reection, thus causing diffused reection. By changing the shape ofthe cover, it is thus possible to alternate between specular and diffused reection. To suit this rst operational principle, the cover is sufciently reective towards the incident light. In this example, the light is incident on the second surface, whichmay also be called the outside ofthe optical device. Figures 2A 2C, which correspond to gures 12 14ofWO 2021 / 032752 A1, show a second operational principle. Reference is rst made to the substrate which spans the support on an opposite side ofthe cover, in order to dene a cavity between the cover and the substrate. The substrate is partly reective and partly transmissive. The cover is relatively reecting. Light incident on the substrate is thus partly transmitted and partly reected. The transmitted light reects on the rst surface ofthe cover, i.e. coming from the inside, and is transmitted back through the substrate, where it interferes with the light reected by the substrate. Depending on the wavelength ofthe light and the distance between the cover and the substrate, the interaction can be constructive or destructive. Since that distance changes when the cover changes shape, the interferometric characteristics ofthe optical device can be changed. Figures 6 and 7 show even otherways ofusing the changing cover contour prole. In the case ofgure 6, an optical element is shown with a substrate 106 that is relatively reective. The cover 101 in this case is relatively absorbing. Nevertheless, ofan incoming lightbeam 601, at least some lightmay be transmitted towards the substrate 106 as transmitted lightbeam 603. This reects back via the substrate 106 as reected light 604. Due to interference ofthe transmitted lightbeam 603 and the reected light 604, a pattern ofnodes and antinodes is present. The cover 101 can then be moved, e.g. by changing its cover contour prole or its position with respect to the support, to place the cover at an antinode for absorbing the light, or at a node for not or absorbing less the light. Accordingly, the exiting light 605 can be present in less ormore intensity by controlling the cover. This principle is called interferometric absorption. Figure 7 shows the principle ofinterferometric reection, similar to g. 2, but with light 601 incident the cover. In this case, light is partially transmitted through the cover 101, and reected at the substrate 604, which for that purpose is reective. The cover 101 reects some light 605, but also transmits some light 603. After reecting 604 from the substrate 106, light passing through the cover 101 again interferes with the reected light 605. By controlling the position or cover contourprole ofthe cover 101, control is possible ofwavelengths oflight that do or do not interfere constructively. In both cases, light transmitted through the covermay actually be refracted. However, since the gures show a specic example oflight incident normal to the cover, the wording transmitting was used. The invention can howeverbe applied, depending on the use-case, to non-normal light also. These principles have been described only briey herein, as the operational principles involved are in themselves known, and have been applied e.g. inWO 2018 / 228671 AI (see gures I and 2). These principles thus show thatby varying the reectance and / or transmittance and / or absorbance ofthe cover and the substrate, and the direction atwhich light is incident (from outside or inside the optical device), it is possible to cause the cover to create a certain interaction with the light, optionally in cooperation with the substrate. The interaction changes when the cover shape changes, i.e. when the cover contourprole changes. There are some limits as to how the optical element ofWO 2021 / 032752 AI can be used in optical systems. The application therefore has as its object to provide amore versatile optical system. More specically, the optical element ofWO 2021 / 032752 AI, and that ofclaim 1, need relatively specic light conditions in order to work optimally. While it is possible to provide such conditions using a collimated light source, this limits the application ofthe optical system as a whole. Consequently, a need exists to provide an optical system with less such limitations. The object is achieved by an optical system according to the preamble, which is characterized in that it further comprises an accumulator. Said accumulator can accumulate light from an external source of light, such as a source ofdiffused light. As a result, an optical system is obtained that can use abroader range oflight inputs. In particular, it is possible to use diffused light as a source. One such example is ambient light such as daylight. This severely reduces the amount ofpowerneeded to operate the optical system. Other sources ofambient light can also be used the same way, including when the illumination is direct, indirect, or both. For example, light used to illuminate a room, e.g. from an articial light source and / or the Sun, can be used accordingly. Ambient light herein is thus dened as contrasting with purpose-specic light, thatwould be generated specically for illuminating the optical element. As an example ofpurpose-specic light, laser light is envisioned. One another example is any purpose-specic light with direct or indirect illumination including but not limited to light emitted from sources such as laser diodes, light emitting diodes and broadband lamps. In principle, all type ofsources ofincandescence, luminescence or indirect illumination could be used as source in this invention. At this time, it is noted that optically relevant elements, such as the diffusor, condenser, collimator, beam splitter, lens, polarizer, lter, mirror, referred to in this applicationmay be provided as an array ofmicro-elements having the required properties. As an example, a diffusor may be provided as an array ofmicro-diffusors. Typically, but not necessarily, the array would be provided as alm material comprising the micro elements. The same is true for the other optically relevant elements. On the other hand, and as an alternative, the traditional variants ofthe optically relevant element could be used. In case ofthe diffusor, this could be called amacro diffusor, macro in this case meaning that a single element performs the optical function as opposed to many micro variants ofthe same element. This can also be true for the other optically relevant elements mentioned above. An example ofan optically relevant element forwhich the same can apply, is a light source. E.g. in case ofan articial light source, this may be present as amacro light source, such as an incandescent bulb, iridescent tube, etc. ofcourse, aLED lamp can also be used, in all cases possibly being composed of several sub-sources. These are contrasted however to an array of micro-sources, possibly present as alm comprising said sources. As an example, an array of micro-LEDs is envisioned. It is noted that the skilled person is readily able to distinguish between sources with several large-scale LEDs and micro-LEDs. Nevertheless, micro LEDs are likely to be no bigger than 10 times the optical element, whereas macro LEDs are likely over 100 times bigger. The accumulatormay comprise a diffusing device, which could for example be a diffusor or alm comprising an array ofdiffusors. A diffusing device can be used to make sure that at least some ofthe incident light, regardless of its angle ofincidence or collimation, reaches the optical elements under optimal conditions. The diffusing device is particularly useful for instance to input indirect illumination from the Sun or articial light into the system, e.g. input ambient light into the system. The accumulatormay comprise, additionally or alternatively, a condensing device, which could for example be a condenser or alm comprising an array ofcondensors. The use ofa condensing device may be particularly useful to focus or collimate an otherwise diverging source of light, such as that produced by a purpose-specic light source. When the system includes a condensing device, many external light sources readily available could be used as light source, whereas previously only specically provided light sources for the purpose were suitable. The accumulatormay comprise a collimating device, which could for example be a collimator, arranged to direct lighttowards the at least one optical element. The collimating device may be used to enlarge the portion ofincident light that is usable for modulation by the optical element(s). It is also possible to include a source oflight in the system, so that the system becomes stand alone, or can be used in the dark. Said source would thus be a purpose-specic source of light, contrasting to ambient light sources. Ifthe source is a source ofnon-collimated light, the optical system may comprise a collimating device (e.g. as part ofthe accumulator explained above). Preferably, the collimating device is arranged to direct the light normal to the at least one optical element. The normal directionmay be dened as normal to a plane spanning the support at a side thereofcorresponding to the cover. Additionally or alternatively a condenser could be used forthe same or similar purpose. Normal incident lightmay be modulated relatively effectively by the optical element. The systemmay further comprise abeam splitting device, which could for example be abeam splitter, arranged between the accumulator and the at least one optical element. Using the beam splitting device allows to take in light from the accumulator at the optical element(s), whichmay then reect light back to a userthrough the beamsplitter. Accordingly, a userwould see an image formed by the optical element(s), and the optical element(s) and accumulatorthemselves can be hidden from view. The beam splittermay be provided as alm material. In particular, in combination with an accumulator provided as alm material, wherein both could be integrated in the optical element, as opposed to the accumulator and the at least one optical element being arranged on mutually perpendicular ports ofthe beam splitting device. described herein. Instead ofa beamsplitter, it is also possible in this case to include a light guide plate, which could for instance allow edge- lighting the element via the light guide plate. As yet another alternative, a system ofgratings connected to waveguides could be used to direct light from a front light illumination system onto the optical element. Instead of, or additional to, the beam splitting device, other optical componentsmay also be used, such as polarizing devices and (colour) ltering devices. These may provide an efciency benet. At least one lensing device may be provided for forming an image.A lensing device may be a lens. In particular, the accumulator and the at least one optical element are arranged on mutually perpendicular ports ofthe beam splitting device, and the at least one lensing device is arranged on a port ofthe beam splitting device directly opposite the at least one optical element. As was explained above, the lensing device may be provided as an array ofmicrolenses, e.g. in alm form. Such an arraymay allow tuning accurately the optical properties ofeach lens to obtain a resulting image specically suitable for the optical system ofclaim 1. The systemmay comprise an array ofoptical elements, e.g. to form collectively an image or to create a large effective area. Using an array ofoptical elements, several congurations can be made. As an example, a beam splittermay be used together with an array ofmicrolenses, to allow input from an accumulator to reach the optical elements, and to then be output to a user. Each microlense may be integrated in each optical element.Altematively, and to make maximum use ofeach optical element, the array ofoptical elements and the array ofmicrolenses may be aligned. In general, when an array ofoptical elements is used, and an array ofmicro-elements as described above, it is advantageous ifthese are aligned. The beam splittermay however also be present as alm material comprising micro-beam splitters. Additionally or alternatively, the micro beam splittersmay be integrated with each optical element. In any case, the micro beam splitters can be aligned with the optical elements.A lens can be used at a collective output port ofthe micro beam splitters, or an array ofmicrolenses can be used, as alm material or integrated in the optical elements. The invention also relates to a use ofan optical system as described hereabove, to display an image using ambient light, optionally sunlight, and / or purpose-specic light, optionally laser- based light, as a light source. As was described before, the accumulator allows using ambient light as an input. Before, itwas only possible to form images using a specically provided light source, which would provide light at a specic angle ofincidence or with predened collimation. Alternative uses are to project an image orvideo into an eye, into a conventional combiner, into a waveguide combiner, into a projector screen or into a wall using ambient light, optionally sunlight, and / or purpose-specic light, optionally laser-based light, as the light source. The invention also relates to a use ofan optical system according to any ofthe preceding claims, to communicate using modulated light, with ambient light, optionally sunlight, and / or purpose-specic light, optionally laser-based light, as a light source. Since the optical element can modulate light, it can be used to transfer information, for instance in communication. Using the accumulator, communication is made possible with a large variety ofsources, such as natural light. Another variety ofsources that can be used is a light emissive diode or a lamp, both ofwhich could be used as an input to the optical element, which can then be used to inuence the light, e.g. for communication. The optical element described herein can be ofany suitable type, and provides optical behaviour based on any number of suitable principles. As an example, the optical device can operate by reecting light using the cover. For that purpose, it is possible the cover has a relatively large reectance as compared to its transmittance. As an example, the value oftransmittance divided by reectance would be not more than 0.5, preferably notmore than 0.25, more preferably notmore than 0.1, most preferably not more than 0.01. The transmittance, reectance and absorbance dened herein may be measured at a wavelength X which varies from 10nm to 3000 um. In one aspect, most preferably 380 to 740 nm. In another aspect, more preferably from 10nm to 200 nm, most preferably from 13 nm to 193 nm. In another aspect, more preferably from 700nm to 2000 nm, most preferably from 850nm to 1550 nm. In another aspect, more preferably from 30 000nm to 3 000 000 nm. Ofcourse, absorptionmay also be considered. As an example, the optical device can operate by absorbing light using the cover. For that purpose, it is possible the cover has a relatively large absorbance as compared to its reectance. As an example, the value ofreectance divided by absorbance would be notmore than 0.5, preferably notmore than 0.25, more preferably notmore than 0.1, most preferably notmore than 0.01. The absorbance and reectance dened above may be measured at a wavelength X which varies from 10nm to 3000 um. In one aspect, most preferably 380 to 740 nm. In another aspect, more preferably from 10nm to 200 nm, most preferably from 13 nm to 193 nm. In another aspect, more preferably from 700nm to 2000 nm, most preferably from 850nm to 1550 nm. In another aspect, more preferably from 30 000nm to 3 000 000 nm. The optical elementmay be congured for reecting light incident on the second surface. In that case, the transmittance and reectance may be measured for light incident the second surface. Alternatively, the optical elementmay be congured for reecting light incident on the rst surface, in that case, the transmittance and reectance may be measured for light incident the rst surface. Besides using the cover for reection only or mainly, it is also possible to employ reective interference, taking place mainly between a reected lightbeam at the substrate (or cover) and a refracted lightbeam through the substrate (or the cover) that the cover (or substrate) reects, or absorbing interference, taking place mainly between a reected light bean with the incident lightbeam at the substrate (or cover) and its absorption at the cover (or substrate). An optical element congured for this purpose is called an interferometric optical device. The absorbance ofthe covermay accordingly also be relevant, as explained above. The interference may take place for light incident the second surface, or for light incident the rst surface. In the latter case, a substrate is needed below the cover, as is described further below. The substrate is congured for transmitting a part ofthe light and reecting a part ofthe light. The transmitted light is then reected on the cover, and transmitted back outthrough the surface. The egressing light interferes (constructively or destructively) with the directly reected light. Depending on the position ofthe cover with respect to the substrate, it is possible to change the interference-based behaviour ofthe optical element. Depending on the desired optical behaviour, it is ofcourse possible to use a cover with different ratios ofreectance, transmittance and absorbance, optionally in combination with e.g. a reective, transmissive or absorbing substrate, the terms reective, transmissive or absorbing being dened using the same ranges for these respective quantities, and / or the same ratios between them as is dened for the cover. In general, the optical properties for the substrate are chosen complimentary to the optical properties ofthe cover. The invention is not limited to any such combination, rather to providing the optical system as in the preamble, with an accumulator as is described in the characterizing portion ofclaim 1. Ofcourse, the substrate need not be square or rectangular. The substrates shape in general is not important, it is even possible for a single substrate to span multiple optical elements. More relevantmay be the shape dened within the support, as this denes the shape ofthe optical element in plan view. It is possible this shape is square or rectangular, to create a pixel-like element, but circular optical elements are also envisaged. The invention may howeverbe applied to optical elements ofall shapes. This is true for all embodiments described herein, whether they do or do not have a substrate. It is noted that for some shapes ofoptical elements, the substrate is rigid and planar, while for others it is possible for it to be exible and / or curved. In such cases, the spacer and cover are adapted to the substrate, in such away that the second surface ofthe cover is approximately parallel to the substrate. In this case, the cover is preferably reective, for instance as expressed in the ratio above. The substrate is not as reective, for example having a ratio oftransmittance divided by reectance ofmore than 0.5, more than 0.75, more than 0.9 or even more than 0.99, or even more than 1, preferably for light incident from a surface ofthe substrate facing away from cover. The opposite direction is also possible, where the cover transmits and reects light, and the substrate reects the transmitted light. In this case, the coverwould be relatively transmissive, for example having a ratio oftransmittance divided by reectance ofmore than 1, for light incident the second surface, so that it is relatively transmissive. Said ratio could for instance be between 1 and 3, such as between 1.5 and 2.5, such as around 2. The absorbance could in this case be relatively high. The substrate would preferably be reective for light incident a surface ofthe substrate facing the cover. The reectance could be dened by a ratio oftransmittance divided by reectance ofnotmore than 0.5, preferably notmore than 0.25, more preferably notmore than 0.1, most preferably notmore than 0.0 I. Unless stated otherwise, transmittance and reectance are measured for light normal to the surface ofthe cover. In case a cover is used that is relatively reective, a value ofabsorbance divided by reectance ofthe cover can be less than 0.5, preferably notmore than 0.25, more preferably not more than 0.1, most preferably notmore than 0.01, for light incident the rst and / or second surface, depending on the desired optical behaviour. It is noted that in all cases, the position and shape ofthe cover inuences how the optical device interacts with incident light. Other operational principles which rely on the change ofthe cover position and shape can however also be applied, and the current invention is thus not limited to either reective or interferometric operational principles. In any case, the invention is not limited solely to a cover with a changing shape or a changing cover. In terms ofclaim 1, this can be realized by dening the spatial arrangement ofthe cover with respect to the support. After all, a cover that has not changed in shape but is at a different position with respect to the support, still has a different spatial arrangement as seen in cross section ofthe coverwith respect to the support. As such, depending on the use, changing the position ofthe cover (without changing its shape) or changing the shape ofthe cover, thereby changing partially its position, could be used interchangeably. The covermay comprise a 2-dimensional portion. The 2-dimensional portion may be an extreme membrane. For the purpose ofthe invention in general however, it is sufcient ifthe 2- dimensional portion is sufciently thin to be deformed and / ormoved using the applicable means. In general, it is not necessary, however possible, that the 2-dimensional portion has favourable optical properties in and of itself. Instead, it is possible to provide the desired optical properties using additional material, such as an additional layer or an amorphous portion ofthe cover, which could be or could comprise a metal or an additive. In that regard, reference is made toWO 2021 / 032752 AI which explains multiple congurations ofthe cover. The skilled person is readily able to vary e.g. the thickness and material ofthe additional material to arrive at desired optical properties for the cover. In that regard, it is noted the 2-dimensional portionmay function as a carrier, whereas the additional material provides desired optical properties. The 2-dimensional portionmay be as dened in embodiment [39a] ofWO 2021 / 032752 AI. Accordingly, the 2-dimensional portion may be one ormore ofthe following: a. One ormore selected from the group consisting of: C, BN, P, MoS2, MoSe2, MoTe2, WS2, WSe2, WTe2, NbS2, NbSe2, NbTe2, TaS2, TaSe2, TaTe2, TiSe2, VSe2, CrS2, CrSe2, B, Ge, Si, Si2BN, Sn, Pb, P, Sb, Bi. The preferred C in this context is one ormore selected from the group consisting of: graphene, one ormore graphitic layers and graphyne, preferably graphene. The preferredBN in this context is h-BN. The preferred P in this context is black phosphorus or phosphorene. The preferred B in this context is borophene. The preferred Ge in this context is germanene. The preferred Si in this context is silicene. The preferred Sn in this context is stanene. The preferred Pb in this context is plumbene. The preferred Sb in this context is antimonene. The preferred Bi in this context is bismuthine, b. One ormore transition metal chalcogenides, each being a transition metal chalcogenide not listed in a., c. One ormore oxides, each being an oxide ofa species listed in a. or b., d. One ormore atomic intercalated variants, each being an atomic intercalated variant ofa species listed in a. or b., e. One ormore physically, chemically, mechanically and / or electromagnetically functionalised derivatives, each being a chemically functionalised derivative ofa species listed in a. or b..A preferred physical functionalisation is perforation or atomic barrage treatment.A preferred mechanical functionalisation is stretching or stressing.A preferred electromagnetic functionalisation is application ofa voltage. In one aspect ofthis embodiment, the 2-dimensional portion is a combination selected from the group consisting of: a., b., c., d., e., a.+b., a.+c., a.+d., a.+e., b.+c., b.+d., b.+e., c.+d., c.+e., d.+e., a.+b.+c., a.+b.+d., a.+b.+e., a.+c.+d., a.+c.+e., a.+d.+e., b.+c.+d., b.+c.+e., b.+d.+e., c.+d.+e., b.+c.+d.+e., a.+c.+d.+e., a.+b.+d.+e., a.+b.+c.+e., a.+b.+c.+d. and a.+b.+c.+d.+e.. Specically, the 2-dimensional portionmay comprise or be graphene or boron nitride or both.A preferred boron nitride is hexagonal boron nitride. Graphene is preferably chemical vapour deposited. Boron nitride is preferably chemical vapour deposited. In one aspect ofthis embodiment, the 2-dimensional portion comprises graphene, preferably is graphene. In one aspect ofthis embodiment, the 2-dimensional portion comprises boron nitride, preferably is boron nitride. As mentioned earlier, the thickness ofthe 2-dimensional portion is relatively small. For instance, 1mm or less, preferably 10 pm or less, more preferably 1000nm or less, more preferably 100nm or less, more preferably 50nm or less. In one aspect ofthis embodiment, more preferably 10nm or less, more preferably 5 nm or less, most preferably 1 nm or less. A minimum thickness may be dened as 25 pm or more, preferably 69pm or more, more preferably 100pm or more. In one aspect ofthis embodiment, the thickness is 1 nm or more, preferably 3 nm or more, more preferably 5 nm ormore, more preferably still 10nm ormore. In another aspect ofthis embodiment, the thickness is 15 nm or more, preferably 20nm or more, more preferably 30nm or more. Accordingly, the 2-dimensional portionmay be relatively light per unit area, such as 24 kg / m2 or less, preferably 2.4- 101 kg / m2 or less, more preferably 2.4- 102 kg / m2 or less, more preferably 2.4- 103 kg / m2 or less, most preferably 1.2- 103 kg / m2 or less.A lower limit on the same weight per unit area is 1.7- 109 kg / m2 or more, preferably 3.4- 108 kg / m2 ormore, more preferably 1.8- 107 kg / m2 or more. In one aspect ofthis embodiment, the mean density is 5-107 kg / m2 or more, preferably 1.5- 106 kg / m2 or more, more preferably 5.4-106 kg / m2 or more, more preferably 5.7- 105 kg / m2 ormore. Various operational principles for the means are available, and have been identied throughout the previous paragraphs. It is noted that some operational principles may allow exerting a force on the cover only in one direction, whereas for others the same means can be used to exert forces in opposing or even various directions on the cover. In case the operational principle only allows forces in a single direction, further means, whichmay be identical, may be applied on the opposite side ofthe cover, e.g. in amirrored position with respect to the previously mentioned means, so that collectively control can be exerted in both ormore directions. While above an optical element has been described that has means congured to affect the cover, the inverse is also possible and envisaged. Accordingly, the means may alternatively or additionally be arranged to provide an output that is representative ofthe cover changing from the rst cover contour prole to the further cover contour prole. In this manner, the optical element can be used as a sensor responsive to any phenomenon, not necessarily optical, that changes the cover shape. For instance, incident radiation, pressure, sound waves, an electrical charge, temperature, etc. could all be sensed using suitable means. As an example, an electrode could be used to sense a changing electrical charge, e.g. changing in response to a charged cover moving. Ifa predetermined and externally applied electrical charge is applied to the cover, the electrodes could be used to measure deformation ofthe coverby capacitive means, for instance as a result ofincoming radiation or pressure. An electrode or other type ofsensing means would be necessary to measure the changing electric eld as the charged covermoves. In these circumstances, the element described herein need not be described as an optical element per se. In particular, the means and / or furthermeans may each, independent from one another, comprise any one ormore of: - an optical actuator, such as an optical tweezer or photonic circuitry, - ameans for applying or changing radiation incident on the cover, such as a radiation source. - ameans for inuencing a gas pressure acting on the cover, - a speaker or any other sound emitter, - a thermal actuator, operating viathermal expansion, and - an electromagnetic and / or superconducting actuator, for instance operating based on tunneling or eld emission. At this time, it is noted that regardless ofthe actuation method used, given a sufciently small system, any one actuation method will often have some corresponding co-phenomenon in another domain as well. As such, at nano-scale, the actuation method and corresponding co- phenomena usually pair up. Examples ofsuch pairs, whichmay be used in the currently described invention as a non-exclusive list ofexamples, are: - Thermo-electrical and electro-thermal actuation, - Thermo-optical and opto-thermal actuation, - Thermo-magnetic and magneto-thermal actuation, - Opto-electrical and electro-optic actuation, and - Magneto-optic and opto-magnetic actuation. At the same time, quantum and superconducting effects may also play a role. Accordingly, use can be made ofsuch effects ifdesired. It is noted that the substrate may be used to dene a cavity below the cover. The index of refraction of said cavity can be ofinuence on the optical behaviour ofthe optical element. The index ofrefraction ofthe cavity can be inuenced by at least partially lling the cavity. To facilitate said lling the cavitymay be enclosed by one ormore ofthe support, the cover and the substrate, ormay even be sealed entirely. Ifthe cavity is indeed sealed, it can be lled with a substance. Different llings ofthe cavity can lead to different refractive indices, and thus a different optical behaviour. The cavitymay for this purpose be lled with a gas composition. Aside from agas or gas mixture, the cavity may also be lled by a liquid (mixture) and / or liquid crystals, or even a solid lling, whichmay have a greater effect on the refractive index. Another option would be to instill avacuum inside ofthe cavity. Denition of, and lling ofthe cavitymay also be done for other reasons than inuencing the index ofreection, i.e. to provide absorption, to provide structure rigidity, or other reasons. Moreover, the substance lling a cavity can be ofinuence on other than the optical behaviour ofthe optical element, including but not limited to the mechanical response ofthe cover and the electrical inuence ofthe means.A lled cavity can also be used to exert a pressure on the cover, in order to move it using pressure based means. As a further remark, it is noted that the structure described herein as optical element can be used in a different and novel way as well, regardless ofwhether or not the characterizing portion of the claims is applied. In this novel way ofusing the device, a substrate opposite the cover is necessary, so that a cavity is formed between the cover and the substrate. The device is congured to allow entry ofelectromagnetic radiation, such as (visible) light, into the cavity between the support and the substrate, and to allow egress ofthe same, also between the support and the substrate. In contrast to the principles shown above, in which light interacts by being incident the cover (either from the rst or second surface), the lightnow travels substantially parallel to the cover, through the cavity. In this case, the cavity acts like a waveguide. To form a waveguide, the skilled person is able to choose suitable materials for the support, the substrate and the material at the covers rst surface and optionally for material to ll the cavity with, so that the light is inuenced by the cover. This inuence could for example result in a change in amplitude, phase or the state ofthe light. Suitably chosen characteristics, such as optical characteristics, ofthe cover allow interaction with light passing through the cavity. By changing the contour shape ofthe cover, orby changing its position, the waveguide formed in the cavity can be altered. The changing inuence ofthe cover on waves passing through can be used to modulate the light. It is noted that the cover need not actually move or change shape in order to affect the passing light differently. For instance, its strainmay be altered for instilling different optical properties. The invention will be further elucidated with reference to the attached drawings, in which: Figures 1A, 1B and 1C show schematically interaction oflight with an optical element known in the state ofthe art, Figures 2A, 2B and 2C show schematically interference interaction oflight with an optical elementknown in the state ofthe art, Figure 3 shows schematically a device with multiple optical elements, Figure 4 shows schematically a system with the device ofgure 3, Figure 5 shows schematically a different embodiment ofan optical system comprising the device ofgure 3, Figures 6 and 7 show schematically an optical element for different interferometric effects, and Figure 8 shows schematically in perspective view anotherway ofusing the optical element. Figure IA shows interaction oflight with ofa at cover 101, which is supported by supports 104. The parallel rays 601 and 602 are both deected by the same angle and remain parallel after interaction with the cover 101. This constitutes specular reection. Figure 1B shows interaction oflight with a convex cover. Due to the rounded convex cover contour prole, a rst ray 601 is deected by almost 180° and the second ray 602 is only deected by a small angle. The rays 601 and 602 are no longer parallel after reection at the cover. This constitutes diffused reection. Figure 1C shows interaction oflight with a concave cover. Due to the rounded concave cover contour prole, a rst ray 601 is deected by an angle less than 90° and the second ray 602 is deected by almost 180°. The rays 601 and 602 are no longer parallel after reection at the cover. This constitutes diffused reection. Figure 2A shows interference interaction with a at cover. Aside from the supports 104, a substrate 106 is also present in this example ofthe state ofthe art, which lies on the bottom ofthe optical element. The support 104, cover 101 and substrate 106 dene a cavity having a depth 205. The substrate 106 is transmissive and absorbing to an extent and the cover 101 is reective, such that an incoming ray 601 undergoes interference which is dependent on the depth 205. Figure 2B shows interference interaction with a convex cover. The cover 101 ofthe optical element ofgure 12 has been deformed into a convex shape (cover contour prole). This was brought aboutby ameans pushing the cover 101 upwards. This increases the depth 205 and the interference behaviour ofincoming light 601 is altered. Figure 2C shows interference interaction with a concave cover. The cover 101 ofthe optical element ofgure 12 has been deformed into a concave shape (cover contour prole). This was brought aboutby the means pushing the cover 101 downwards. This decreases the depth 205 and the interference behaviour ofincoming light 601 is altered. Now rst referring to gures 6 and 7, it is noted that depending on the optical properties of the cover 101 and the substrate 106, different operational principles are also usable for inuencing incident light. Figure 6 for instance, shows an optical element similar to that ofgures 1 and 2, but with a cover 101 that is relatively absorbing, and a substrate 106 that that is relatively reective. As a result, incident light 601 transmitted 602 through the cover 101 interacts with light reected 604 from the substrate to form a pattern ofnodes and antinodes. The cover can be controlled by means (not shown) to be placed at or away from a node or antinode, to accordingly absorb strongly or less strongly light, so that the intensity ofexiting light 605 can be controlled. In gure 7 a cover 101 is present that is both transmissive and reective, and a substrate that is reective. Accordingly, use can be made ofinterferometric reection, similar to gures 2A 2C, however now the optical element is congured for light incident the cover 101. Otherwise, the optical elementmay be identical to that described above. Figure 3 shows a device 98 with several optical elements 99 arranged in an array of3x3. Each optical element 99 comprises a cover 1 having a rst surface and a second surface, a support, and a means. The cover is orientated with the rst surface directed towards the support, a part of the rst surface is attached to the support.A spatial arrangement ofthe cover as seen in a cross section ofthe cover denes a cover contour prole, and the means is arranged to move the cover from a rst cover contourprole to a further cover contour prole which is different from the rst cover contour prole. The optical elements 99 are seen in plan view, i.e. normal to their cover 1. Figure 4 shows how such a device 98 can be used in a system 97 having multiple optical elements 99 and an accumulator 23. The accumulator 23 is, in the example ofgure 4, a collimating device 23.A source 24 ofnon-collimated light, this case sunlight, is shown. The collimating device 23 collimates the lights and directs it to the device 98. For the sake of clarity, the light in gure 4 is shown parallel to the optical elements 99, but it is preferable ifthe light is directed normal to the optical elements 99. The optical elements 99 modulate the light for a user 25 to see. Another system 97 is shown in gure 5. This system includes a source 24 oflight, which is fed through a condensing device 26 and abeam splitting device 27 to reach the device 98. After modulation, the light is emitted / reected / refracted back through the beam splitting device 27 and nally to a user 25 after passing through a lens 28 in order to form an image. Another exemplary arrangement ofthe optical system is depicted in gure 5, this time using apurpose-specic light source rather than an ambient light source, such as sunlight. Finally, reference is made to gure 8, which shows a perspective view ofa device, such as an optical element, similar to that described herein. Like before, the device has a substrate 106 and support 104, which in this case are monolithic. The support 104 denes a cavity C that is of longitudinal shape in this example. Cover 101 held by the support 104 spans the cavity C. Materials for the support 104, the substrate 106, the material at the covers rst surface and material with which the cavity C is lled are chosen so that the cavity C acts as a waveguide. Incidentwaves 601, such as light, can therefore pass through from one side to another, and egress as exited light 602. Viameans 107, in this case presented on top ofthe support 104, although not strictly necessary, the cover 101 can be moved, or its cover contour prole changed. As a result, the cover 101 at least locally inuences the light passing through the cavity C in order to modulate 1t. It is noted thatterms like preferably, generally and typically are not utilized herein to limit the scope ofthe claims or to imply that certain features are critical, essential, or even important to the structure or function ofthe claims. Rather, these terms are merely intended to highlight alternative or additional features thatmay ormay not be utilized in a particular embodiment ofthe present disclosure. Likewise, forthe purposes ofdescribing and dening the present disclosure, it is noted that the terms substantially and approximately and their variants are utilized herein to represent the inherent degree ofuncertainty thatmay be attributed to any quantitative comparison, value, measurement or other representation, as well as to represent the degree by which a quantitative representationmay vary without resulting in a change in the basic function ofthe subject matter at issue. While certain representative embodiments and details have been shown forpurposes of illustrating the present disclosure, it will be apparent to those skilled in the art that various changes may be made without departing from the scope ofthe disclosure, which is dened in the appended claims.

Claims

1. Optical system, comprising at least one optical element that includes: a. a covering with a first and a second surface, b. a support, and c. a means, whereby: - the cover is oriented with the first surface facing the support, - a part of the first surface is attached to the support, - a spatial arrangement of the deck considered in a cross-section of the cover defines a cover contour profile, - the device is designed to move the cover from a first cover contour profile to a further cover contour profile that differs from the first cover contour profile, with the characteristic that the optical system further comprises an accumulator that carries light from a light source, like a source of diffuse light, accumulates.

2. Optical system according to the previous conclusion, where the accumulator is a diffusion- includes fixture 3. Optical system in accordance with one of the preceding claims, where the accumulator is includes condenser.

4. Optical system in accordance with one of the preceding claims, where the accumulator is a collimator device comprises that arranged to direct light towards at least one optical element to lead.

5. Optical system in accordance with one of the preceding claims, further comprising a light source.

6. Optical system according to the previous conclusion, where the source is a source of non- is collimated light and where the optical system further comprises a collimation device to the to collimate easily.

7. Optical system according to the previous conclusion, where the collimation device is configured to direct the light perpendicular to at least one optical element.

8. Optical system in accordance with one of the preceding claims, further comprising a beam splitter device between the accumulator and at least one optical element has been installed.

9. Optical system in accordance with one of the preceding claims, further comprising at least a lens device for forming an image.

10. Optical system according to at least claims 7 and 9, where the accumulator and the ten at least one optical element on mutually perpendicular ports of the beam splitter be installed, and where at least one lens device on a port of the beam- splitting device is installed directly opposite the at least one optical element 11. Optical system according to one of the claims 9 10, where the lensing device as a series is provided with microlenses, which may be placed between the accumulator and at least one optical element has been installed.

12. Optical system in accordance with one of the preceding claims, comprising a series of optical elements.

13. Optical system according to at least claims 11 and 12, where the set of optical elements and the series of microlenses are aligned.

14. Use of an optical system pursuant to one of the preceding claims, for the displaying an image with ambient light, possibly natural light, as a light source.

15. Use of an optical system in accordance with one of the preceding claims, for the communicate by means of modulated light, with ambient light, possibly sunlight, and / or targeted lighting, possibly laser light, as the light source.

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