Abstract
The present invention relates to a device (100) for light exposure regulation of agricultural goods and energy production, in particular electrical energy production, by converting or transmitting a highly-directional component (81) of incident light (80) and by transmitting a diffuse component (82) of incident light (80), comprising: #an optical arrangement (40) comprising a first optical layer (41), wherein the first optical layer (41) comprises a plurality of primary optical elements (47); #a light energy conversion layer (50) at least partially transparent to light and comprising a plurality of distant light energy conversion elements (51) capable of converting light energy in an output energy; #a shifting mechanism (60) for moving the optical arrangement (40) relative to the light energy conversion layer (50) or vice versa; and #a frame element (10) to which either the optical arrangement (40) or the light energy conversion layer (50) is attached, wherein the shifting mechanism (60) is arranged to displace the optical arrangement (40) or the light energy conversion layer (50) translationally relative to the frame element (10), through one or more translation element (65), wherein the primary optical elements (47) of the first optical layer (41) and the shifting mechanism (60) are designed such that the highly-directional component (81) of incident light (80) is directable onto the light energy conversion elements (51) of the light energy conversion layer (50) and such that the diffuse component (82) of incident light (80) is transmittable through the regions of the light energy conversion layer (50) not covered by the light energy conversion elements (51), and wherein the amount of light transmitted through the device (100) is controllable. Furthermore, the present invention also relates to a corresponding method and use for converting light energy with the aforementioned device.
Claims
1. A device for light exposure regulation of agricultural goods and energy production by converting or transmitting a highly-directional component of incident light and by transmitting a diffuse component of incident light, comprising: an optical arrangement comprising a first optical layer, wherein the first optical layer comprises a plurality of primary optical elements; a light energy conversion layer at least partially transparent to light and comprising a plurality of distant light energy conversion elements capable of converting light energy in an output energy; a shifting mechanism for moving the optical arrangement relative to the light energy conversion layer or vice versa; and a frame element to which either the optical arrangement or the light energy conversion layer is attached, wherein the shifting mechanism is arranged to displace the optical arrangement or the light energy conversion layer translationally relative to the frame element, through one or more translation element, wherein the primary optical elements of the first optical layer and the shifting mechanism are adapted such that the highly-directional component of incident light is directable onto the light energy conversion elements of the light energy conversion layer and such that the diffuse component of incident light is transmittable through the regions of the light energy conversion layer not covered by the light energy conversion elements, and wherein an amount of light transmitted through the device is controllable.
2. The device according to claim 1, wherein the plurality of primary optical elements and the light energy conversion elements are arranged in regular two-dimensional arrays, and wherein the shifting mechanism is arranged to displace the optical arrangement or the light energy conversion layer translationally relative to the frame element in at least two dimensions.
3. The device according to claim 1, wherein the shifting mechanism is arranged to displace the optical arrangement or the light energy conversion layer in such a way that the highly-directional component of incident light is directable onto the regions of the light energy conversion layer not covered by the light energy conversion elements.
4. The device according to claim 1, wherein the shifting mechanism is arranged to displace the optical arrangement or the light energy conversion layer in such a way that the amount of light transmitted through the device can be maximized and minimized.
5. The device according to claim 1, wherein the shifting mechanism comprises one or more guiding elements and/or one or more flexible guiding elements in such a way that the one or more guiding elements or flexible guiding elements are capable of limiting degrees of freedom of the optical arrangement and/or of the light energy conversion layer.
6. The device according to claim 5, wherein the one or more guiding elements and/or the one or more flexible guiding elements are capable of suppressing any rotational movement between the optical arrangement and the light energy conversion layer.
7. The device according to claim 5, wherein the light energy conversion layer is directly attached to the optical arrangement by means of the guiding elements and/or the flexible guiding elements.
8. The device according to claim 5, wherein the guiding elements and/or the flexible guiding elements are arranged to guide the movement of the optical arrangement or the light energy conversion layer on a paraboloid or on a spherical trajectory.
9. (canceled)
10. (canceled)
11. (canceled)
12. The device according to claim 1, wherein secondary optical elements are of refractive type and/or of reflective type and are mounted directly onto the light energy conversion elements in order to further focus the highly-directional component of incident light onto the light energy conversion elements.
13. The device according to claim 1, wherein a light scattering layer is placed below the light energy conversion layer in a direction opposite to the optical arrangement.
14. The device according to claim 1, wherein light spectrum shifting elements are integrated into the light energy conversion layer in-between the light energy conversion elements.
15-32. (canceled)
33. The device according to claim 1, wherein the light energy conversion layer comprises a spectral filter, in particular a UV and/or infrared light filter.
34-41. (canceled)
42. The device according to claim 1, further comprising sensors to monitor environmental parameters comprising such as irradiance, temperature and/or humidity, allowing to optimize the agricultural production.
43. The device according to claim 1, further comprising a feedback control loop to monitor a position of the translation element and/or an output power of the device and/or the amount of light transmitted through the device, wherein the feedback control loop comprises an optical sensor, a photovoltaic sensor, a power meter, a temperature sensor or a combination of several of these sensors.
44-47. (canceled)
48. The device according to claim 1, wherein the device is arranged to be attached to a single-axis or dual-axis tracker.
49. The device according to claim 1, wherein the device comprises further comprising a microcontroller configured to measure the energy production, the amount of transmitted light, an output signal of an embedded sensor and/or a position of the shifting mechanism.
50. (canceled)
51. (canceled)
52. A method for light exposure regulation of agricultural goods and energy production by converting or transmitting a highly-directional component of incident light and by transmitting a diffuse component of incident light, with the device according to claim 1, comprising the steps of: arranging the device between a light source and the agricultural goods; and moving the optical arrangement relative to the light energy conversion layer or vice versa, wherein the shifting mechanism moves the optical arrangement or the light energy conversion layer translationally by one or more translation element in such a way that the amount of light transmitted through the device to the agricultural goods is adjusted.
53. A method according to claim 52, wherein the highly-directional component of incident light is alternatively directed onto the light energy conversion elements of the light energy conversion layer and onto the regions of the light energy conversion layer not covered by the light energy conversion elements, and wherein the diffuse component of incident light is transmitted through the regions of the light energy conversion layer not covered by the light energy conversion elements.
54. (canceled)
55. (canceled)
56. A method according to claim 54, wherein the light emitting elements are provided with energy by the light energy conversion elements.
57. A method according to claim 52, wherein the amount of light transmitted through the device to the agricultural goods is adjusted to match on agricultural goods light requirements for the agricultural goods over seasons.
58. A method according to claim 52, wherein the amount of light transmitted through the device to the agricultural goods is increased at the beginning or at the end of a day.
59. A method according to claim 52, wherein the amount of light transmitted through the device to the agricultural goods is kept constant over the day.
60. A method according to claim 52, wherein a temperature measured at the agricultural goods is maintained constant over the day.
61. A method according to claim 52, wherein the energy production is maximized.
62. (canceled)
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0092] The foregoing and other objects, features and advantages of the present invention are apparent from the following detailed description taken in combination with the accompanying drawings in which:
[0093] FIG. 1A illustrates a first embodiment of the use of a device according to the present invention for agricultural application;
[0094] FIG. 1B illustrates a second embodiment of the use of a device according to the present invention for agricultural application;
[0095] FIG. 2A is a schematic cross-sectional view of the device according to a first embodiment of this aspect of the present invention, where highly-directional light is impinging at normal incidence angle onto the optical arrangement;
[0096] FIG. 2B is a schematic cross-sectional view of the device according to a first embodiment of this aspect of the present invention, where highly-directional light is impinging at a non-normal incidence angle onto the optical arrangement;
[0097] FIG. 3 is a schematic cross-sectional view of the device according to the first embodiment of this aspect of the present invention, where the light energy conversion layer is intentionally misaligned in order to transmit highly-directional light;
[0098] FIG. 4 is a schematic top view of the optical arrangement according to a second embodiment of this aspect of the present invention, wherein the primary optical elements have a hexagonal contour;
[0099] FIG. 5 is a schematic cross-sectional view of the optical arrangement according to a third embodiment of this aspect of the present invention;
[0100] FIG. 6 is a schematic cross-sectional view of the optical arrangement according to a fourth embodiment of this aspect of the present invention;
[0101] FIG. 7 is a schematic cross-sectional view of the optical arrangement according to a fifth embodiment of this aspect of the present invention;
[0102] FIG. 8 is a schematic cross-sectional view of the optical arrangement according to a sixth embodiment of this aspect of the present invention;
[0103] FIG. 9A is a schematic cross-sectional view of the light energy conversion layer according to a seventh embodiment of this aspect of the present invention;
[0104] FIG. 9B is a schematic cross-sectional view of the light energy conversion layer according to an eighth embodiment of this aspect of the present invention;
[0105] FIG. 9C is a schematic cross-sectional view of the light energy conversion layer according to a ninth embodiment of this aspect of the present invention;
[0106] FIG. 9D is a schematic cross-sectional view of the light energy conversion layer according to a tenth embodiment of this aspect of the present invention;
[0107] FIG. 9E is a schematic cross-sectional view of the light energy conversion layer illustrating the light path of the focused incident light in case of a partial misalignment of the optical arrangement.
[0108] FIG. 10 is a schematic cross-sectional view of the light energy conversion layer according to an eleventh embodiment of this aspect of the present invention;
[0109] FIG. 11 is a schematic cross-sectional view of the light energy conversion layer according to a twelfth embodiment of this aspect of the present invention;
[0110] FIG. 12 is a schematic cross-sectional view of the light energy conversion layer according to a thirteenth embodiment of this aspect of the present invention;
[0111] FIG. 13 is a schematic cross-sectional view of the light energy conversion layer according to a fourteenth embodiment of this aspect of the present invention;
[0112] FIG. 14 is a schematic cross-sectional view of the light energy conversion layer according to a fifteenth embodiment of this aspect of the present invention;
[0113] FIG. 15 is a schematic cross-sectional view of the light energy conversion layer according to a sixteenth embodiment of this aspect of the present invention;
[0114] FIG. 16 is a schematic top view of a device according to an seventeenth embodiment of the present invention;
[0115] FIG. 17 is a schematic top view of a device according to a eighteenth embodiment of the present invention;
[0116] FIG. 18A is a schematic cross-sectional view of the device according to a nineteenth embodiment of this aspect of the present invention, where the light energy conversion layer is in its standard position;
[0117] FIG. 18B is a schematic cross-sectional view of the device according to the nineteenth embodiment of this aspect of the present invention, where the light energy conversion layer is in a shifted position;
[0118] FIG. 19 is a schematic cross-sectional view of the optical arrangement and the light energy conversion layer according to a twentieth embodiment of this aspect of the present invention;
[0119] FIG. 20 is a schematic cross-sectional view of the device according to a twenty-first embodiment of this aspect of the present invention;
[0120] FIG. 21 is a schematic cross-sectional view of the device according to a twenty-second embodiment of this aspect of the present invention;
[0121] FIG. 22 is a schematic cross-sectional view of the device according to a twenty-third embodiment of this aspect of the present invention;
[0122] FIG. 23 illustrates an embodiment in which the device comprises a feedback loop to control the relative position of the light energy conversion layer relative to the optical arrangement;
[0123] FIG. 24 illustrates that several devices according to the present invention can be combined to form a single system; and
[0124] FIG. 25 illustrates that thanks to the device according to the present invention the light exposure of plants can be matched to its optimal value.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION
[0125] FIGS. 1A and 1B illustrate a first and second embodiment of the use of a device 100 according the present invention for agricultural application. The general principle of the present invention is to provide a device that permits, thanks to shifting mechanism 65 which is able to translate the light conversion layer 50 relative to the optical arrangement 40, either to collect with high efficiency the highly-directional light component 81, i.e. the collimated light, of the entire incident light 80 coming from a light source, as for instance the sun, or to transmit this component of incident light to agricultural goods placed below the device. The device allows also to transmit the diffuse light component 82 of the incident light 80 to the plants. As will be explained in details below the device 100 is configured such that the light energy from the highly directional incident light 81 arriving “directly” from the sun can be converted by PV cells while the diffuse incident light 82 is transmitted through the device, allowing the transmitted diffuse light 92 to arrive at the plants placed below the device. The device further comprises a shifting mechanism (not shown in FIGS. 1A and 1B) that permits to maximise to light energy conversion or the transmission trough the device whatever position of the sun in the sky. As can be seen in these figures, the device can be mounted on a pole either on the side of the system or in the middle. As explained in details below, thanks to the shifting mechanism of the device 100, the tilt angle to the system 100 relative to the ground does not necessarily need to be changed during the day. FIG. 1A illustrates also that the device can be mounted on a single-axis tracker, with rotating axis R, in order to maximize energy production or put the device in a vertical position to increase the space for agricultural machines.
[0126] In the field of agriculture, the device allows therefore transmitting direct and diffuse light to plants placed below the device and therefore permits to promote the growth of these plants.
[0127] FIGS. 2A and 2B display a photovoltaic device 100 according to first embodiment of the present invention. The device 100 comprises an optical arrangement 40 that comprises at least one first optical layer 41 designed to direct the highly-directional component 81 of the incident light 80 either onto the light energy conversion elements 51 placed on a transparent or translucent light energy conversion layer 50 or onto transparent regions of the light energy conversion layer 50 (the regions between the light energy conversion elements 51), a static frame 10 to which the optical arrangement 40 is attached and a shifting mechanism 60, arranged to move the optical arrangement 40 relatively to the static frame 60, so that the amount of light energy converted by the light energy conversion layer 50 and the amount of transmitted light 92 through this layer can both be adjusted, depending on the relative position of the optical layer 40 and the light energy conversion layer 50. As can be seen in these Figures, the optical layer 40 and the light energy conversion layer 50 are connected together by guiding elements 26, which are in this particular embodiment flexible guiding elements. The guiding elements 26, an actuator 25, and a shifting element 65 are parts of the shifting mechanism 60. The aim of the shifting mechanism 60, and especially of the guiding elements 26, the actuator 25 and of the translation element 65, is to move the light energy conversion layer 50 while allowing only translation along the direction W. In particular, the shifting mechanism 60 is configured such that it forbids any relative rotation, around an axis Z perpendicular to the plane of the device, between the optical arrangement 40 and the light energy conversion layer 50. Important to note is that even if in FIGS. 2A and 2B the light energy conversion layer 50 is movable relative to the frame 10 and the optical arrangement 40 fixed, the device according to the present invention could provide for a movable optical arrangement 40 and a fixed light energy conversion layer 50. Moreover, in the embodiment presented in FIGS. 2A and 2B the optical arrangement 40 comprises besides the first optical layer 41, that is configured to direct the collimated incident light 81, a second optical layer 42. In this embodiment, the second optical layer 42 takes the form of a rigid transparent plate, for instance a glass plate, that is mainly foreseen to protect the first optical layer 41 against environmental conditions.
[0128] FIG. 2A depicts the situation when the incidence of direct sunlight is normal to the plane of the device 100. The optical arrangement 40, here the first optical layer 41, can concentrate and transmit the highly-directional component 81 of the incident light 80 to the light energy conversion elements 51, while diffuse incident 82 is transmitted through the light energy conversion layer 50 allowing transmitted light 92 to arrive at the plants placed below the device 100.
[0129] In comparison, FIG. 2B illustrates the device 100 when the highly-directional component 81 of the incident light 80 impinges on the system at a larger incidence angle α, corresponding to a situation when the sun has moved in the sky during the day. Thanks to the shifting mechanism 60, when the highly-directional component 81 of the incident light 80 can still optimally be directed onto the light energy conversion elements 51, while diffuse incident light 82 goes through the system to the plants placed below the device 100. Thanks to the guiding elements 26, the light energy conversion layer 50 is not only moved in translation in direction W but also in a direction parallel to the axis Z (see FIG. 2B). By this, the light energy conversion elements 51 can be located at the focal point of the focusing elements of the first optical layer 41 independently of the position of the source of incident light.
[0130] FIG. 3 illustrates that the device 100 is configured such that the shifting mechanism 60 can intentionally misalign the device 100, in order to transmit the highly-directional component 81 of the incident light 80 through the system 100, such that both the diffuse 82 and highly-directional 81 components of incident light 80 can be transmitted to the plants below. This is advantageous when the plants require more irradiance than what diffuse sunlight 82 alone can provide over one day. For instance, the device 100 can be configured to be misaligned in the early mornings or late afternoons, when the sun is low and the efficiency of light energy conversion would anyway decrease. More generally, the device 100 can be configured to be misaligned at any time during the day, e.g. based on manual inputs or the feedback of a sensor measuring the amount of energy received by the plants (not shown here). It should be noted that this misalignment can be total or only partial, allowing to precisely adjust the amount of incident light transmitted to the light energy conversion elements and the amount of incident light transmitted through the module at any time. It is also important to note that in this configuration the additional light 91 transmitted by the device is significantly more diffuse than the highly-directional component 81 of incident light 80. More specifically, thanks to the optical power of the optical arrangement 40, the highly-directional component 81 of incident light 80 is significantly diffused before being transmitted to the plants below the device. This is advantageous to provide a more homogeneous light distribution on the crops.
[0131] FIGS. 4 to 22 present different embodiments of the optical arrangement 40, the light energy conversion layer 50, and the shifting mechanism 60. Important to note, that these embodiments can be combined to form further embodiments in the frame of the present invention.
[0132] As illustrated in FIG. 4, the first optical layer 41 of the optical arrangement 40 of a device according to the present invention can comprise a plurality of primary optical elements 47, for instance lenses or mirrors, that have advantageously a hexagonal contour 47a. By this, the primary optical elements 47 can be arranged side-by-side and cover the entire surface of the first optical layer 41 of the optical arrangement 40 without any gaps.
[0133] FIG. 5 illustrates another embodiment of the present invention where the optical arrangement 40 is composed of first and second optical layers 41 and 42 that are attached together. The first and second optical layers 41, 42 can be either directly bonded together, for instance by casting or overmolding processes, or using a plasma activation process (not shown here). The two optical layers 41, 42 can also be bonded together by means of an intermediate adhesive layer 45, as for example silicone glue or UV cured acrylic glue, as depicted in this Figure. The second optical layer 42 is advantageously highly rigid to structure the optical arrangement 40 while a more flexible first optical layer 41, for instance made out of a polymer such as silicone rubber or PMMA, is molded or cast to a complex optical shape, for instance by injection molding.
[0134] FIG. 6 shows a further embodiment of the present invention in which the first optical layer 41 of the optical arrangement 40 is composed of a first optical sub-layer 41a and a second optical sub-layer 41b. The first and second optical sub-layers 41 and 41b are advantageously made of a polymer such as silicone rubber, overmolded or bonded on both faces of a third optical layer 43 which is formed as a rigid transparent substrate made for instance out of glass.
[0135] The optical arrangement 40, of the embodiment presented in FIG. 7, comprises a first optical sub-layer 41a, a second optical sub-layer 41b, a second optical layer 42 and a third optical layer 43. Two layers 41a and 41b are made out of a polymer overmolded or bonded on both sides of the rigid third optical layer 43 and attached to another rigid second optical layer 42 on the front side. The space within the two rigid second and third optical layers 42 and 43 can advantageously be hermetically sealed and filled with an inert gas, such as argon, helium, neon, krypton, xenon, radon or a combination thereof. This is beneficial in order to use the optical arrangement 40 as a double-glazed window providing thermal insulation, for instance when the device is used as a façade or roof element of a greenhouse. Similarly, and as shown in FIG. 8, the optical arrangement 40 can be configured as a triple-glazed window. To this aim, a rigid fourth optical layer 44 is added on the backside of the optical arrangement 40 presented in FIG. 7. This is advantageous to add further thermal insulation capability to the device.
[0136] FIG. 9A illustrates a further preferred embodiment of the present invention. In this embodiment, the light energy conversion layer 50 comprises a plurality of light energy conversion elements 51, wherein the number of light energy conversion elements 51 is purposely chosen smaller than the number of primary optical elements 47 in the optical arrangement 40. By this a device with higher light transmission capability can easily be manufactured. As explained below, this is particularly advantageously when the light energy conversion layer 50 of the embodiment presented in FIG. 9A is combined with one of the elements shown in FIGS. 9B, 9C, 9D and 10.
[0137] In FIG. 9B, light shaping elements 56 are machined into the light energy conversion layer 50 in order to achieve some desired optical effects, such as increasing the divergence angle of the focused highly-directional component of incident light 83 impinging on a region of the light energy conversion layer not covered by a light energy conversion element 51. This is advantageous when the device is misaligned in order to control the intensity, direction and/or divergence of the light transmitted through the device.
[0138] In FIG. 9C, several light diffusing elements 57′, 57″ and 57′″ with various degrees of transmissivity are integrated into the light energy conversion layer 50. This is advantageous in order to control the degree of diffusivity of the beam of direct sunlight focused by the optical layer 40. Thanks to the shifting mechanism 60, the focused light 83 can be targeted onto one or none of the light diffusing elements 57′, 57″ and 57″, in order to transmit light with a controlled degree of transmissivity.
[0139] In FIG. 9D the primary light energy conversion elements 51 are encapsulated by encapsulating layer 58, made for instance out of ethylene-vinyl acetate (EVA), or poly-ethylene-vinyl acetate (PEVA). The encapsulating layer 58 is sandwiched between a first protective layer 59′ of the light energy conversion layer and a second protective layer 59″, the two protective layers 59′ and 59″ being transparent or translucent. This is advantageous to protect the light energy conversion elements from stress and contaminants, such as humidity, dust, etc. The two protective layers 59′ and 59″ can advantageously be made of glass for its rigidity and resistance to shocks. Alternatively, they can be made of a polymer such as PET to make a more lightweight device.
[0140] FIG. 9E illustrates the light path of the focused highly-directional component of the incident light 83 when the optical arrangement is purposely partially misaligned relatively to the light energy conversion layer 50. Thanks to this misalignment, part of the direct incident light 83 impinges on the light energy conversion elements 51 while another part 84 is transmitted through the layer 50 and can be provided to the agricultural goods placed below the device. With other words, by purposely misaligning the conversion layer 50 towards the optical arrangement 40, the light exposure of the goods placed below the device can precisely be regulated while the component of the incident light not transmitted through the device is used for energy production.
[0141] In FIG. 10, a further embodiment of the present invention is depicted. This embodiment is similar to the embodiment shown in FIG. 9 but a light scattering layer 52, for instance in form of a translucent substrate, has been added below the light energy conversion layer 50. This allows to further diffuse focused highly-directional component of incident light 83 in case of misalignment between optical arrangement 40 and light energy conversion layer 50, or when the number of light energy conversion elements 51 is purposely chosen smaller as the number of primary optical elements 47. As can be seen in FIG. 10, the aim of the light scattering layer 52 is to homogenize the illuminance which can be favorable to promote plant growth.
[0142] In yet another embodiment of the present invention displayed in FIG. 11, secondary optical elements 48 are provided directly on the light energy conversion elements 51. The secondary optical elements 48 ensure a better collection of focused highly-directional component of incident light 83 by the light energy conversion elements 51. As shown in FIG. 11, the secondary optical elements 48 increase in particular the alignment tolerance between the optical arrangement 40 and the light energy conversion layer 50. When several light energy conversion elements 51 are mounted on the same substrate, the light concentrated and transmitted 83 by each primary optical element 47 of the optical arrangement 40 can be slightly misaligned, as illustrated on the right side of FIG. 11. The secondary optical elements 48 allow therefore for minimizing the losses related to the mentioned possible misalignment. The use of the secondary optical elements 48 allows furthermore to more precisely regulate the light transmitted through the device.
[0143] FIG. 12 shows another embodiment of the present invention. Here, tertiary optical elements 49 are arranged on top of opaque structures 53 provided on the light energy conversion layer 50. The tertiary optical elements 49 are configured to modify the path of transmitted light 83 such that it does not impinge on an opaque but not energy producing area of the light energy conversion layer 50 and to ensure optimal transmission through the device. Examples of opaque structures 53 include some connection lines provided to electrically interconnect the light energy conversion elements 51 in form of PV cells, or pads on which the light energy conversion elements 51 or other electrical components are assembled. Tertiary optical elements 49 of reflective or refractive type can be used to “mask” these opaque structures and improve transmission of transmitted light 83 through the light energy conversion layer 50.
[0144] As shown in FIGS. 13 to 15 the light energy conversion layer 50 can comprise light emitting elements 54. In the embodiments of these Figures, the device can be used as a lighting fixture, which is advantageous in various scenarios. When the device is installed above agricultural land, the light emitting elements 54 can provide light to the plants in the absence of sunlight, for instance at night or on cloudy days, or provide additional light within a specific spectral band (such as blue-shifted light below 450 nm or red-shifted light above 650 nm), optimized for the plants being grown and their stage of growth.
[0145] The light emitting elements 54 can be advantageously light emitting diodes, which can be placed on the backside of the light energy conversion layer 50 as shown in FIGS. 13 to 15. It can be advantageous to align the light emitting elements 54 with the light energy conversion elements 51, as shown in FIGS. 13 to 15, in order to minimize shading on the transparent substrate. As illustrated in FIG. 14, an additional light scattering layer 52 can be foreseen to homogenize the output of the light emitting elements 54. Alternatively, as illustrated on FIG. 15, quaternary optical elements 55 can be mounted on the light emitting elements 54 to direct the light output of these elements. Advantageously, the quaternary optical elements 55 are in the form of collimators to collimate the light output of the light emitting elements 54.
[0146] FIG. 16 illustrates that, according to a further embodiment of the present invention, the shifting mechanism 60 comprises three shifting elements 25 here in the form of actuators 25, two of which are disposed in parallel on the same axis W but at opposite ends of the translation element 65, here in the form of a frame around the optical arrangement 40, and a third one in a direction normal to the first two. This configuration permits to control and cancel any parasitic rotation Y of the translation element 65 around the axis A.
[0147] It goes without saying that the shifting mechanism 60 as shown in all embodiments of the present invention is capable of moving either the optical arrangement 40 or the light energy conversion layer 50 translationally in one, two or three degrees of freedom relative to the frame element 10, thereby enabling the primary optical elements 47 to optimally direct the highly-directional component 81 of the incident light 80 onto the light energy conversion elements 51.
[0148] The different configurations of the present invention allow the translation element 65 of the device to perform only small strokes, ranging from for example from a few micrometers to a few centimeters. Such displacements are typically at least two orders of magnitude smaller than the outer size of the device. The displacements could be for example of the same order of magnitude as the size of the primary optical elements 47. The displacements are limited to translational movements along one, two or three axes (with one, two or three degrees of freedom). Rotations are blocked or cancelled by means of a specific disposition of the guiding elements 26 combined with an arrangement of one or more actuator 25.
[0149] As illustrated in FIG. 17, several devices can be combined together, wherein one actuator 25 and one shifting element 65 are configured in such manner that the optical arrangements 40 of all the devices can be translated at the same time.
[0150] According to another embodiment of the present invention, illustrated in FIGS. 18A and 18B, the light energy conversion layer 50 is directly attached to the optical arrangement 40 by means of several, here four guiding elements 26. In this case, the guiding elements 26 are advantageously flexible guiding elements such as leaf springs, or any suitable type of flexible elements such as double ball joints, double magnetic ball joints or double universal joints, such as double cardan joints. As illustrated in FIG. 18B, the guiding elements 26 are designed in such a way that when the actuator 25 pushes or pulls the translation element 65 in the direction W, the light energy conversion layer 50, mounted on the translation element 65, moves along a curved trajectory W′, for instance a portion of a paraboloid or a spherical trajectory. In other words, the guiding elements 26 transform the linear movement of the actuator 25 into a curved movement of the translation element 65. Of course, and in order to be able to transmit diffuse light to objects, for instance to plants, placed below the optical arrangement, the translation element 65 is transparent or is in a form of a scattering layer 52 as presented for instance in FIG. 10.
[0151] In the embodiment of FIGS. 18A and 18B, the frame 10 is at least partially open at the bottom and a flexible membrane 15 is provided between the static frame 10 and the shifting element 65. Of course, the flexible membrane 15 could also be provided between the static frame 10 and the light energy conversion layer 50. The flexible membrane 15 seals the gaps between the translation element 65 or the light energy conversion layer 50 and the frame 10, while allowing the translation element 65 to move both laterally and vertically. Thanks to the flexible membrane 15, the light energy conversion elements 51 (not shown in these figures) and the optical arrangement 40 are protected against environmental conditions in particular against humidity.
[0152] FIG. 19 shows another embodiment of the present invention in which the flexible guiding elements 26 can be foreseen as integral parts of the optical arrangement 40. As illustrated in this Figure, the flexible guiding elements 26 can advantageously be designed such that the optical arrangement 40 is moved along a curved trajectory W′ when the shifting mechanism 60 is actuated. The flexible guiding elements 26 can be attached to the light energy conversion layer 50 by various means, including gluing, clamping or direct molding onto the light energy conversion layer 50.
[0153] In another embodiment of the present invention illustrated in FIG. 20, a plurality of sliders 27 are foreseen between the optical arrangement 40 and the light energy conversion layer to ensure, in combination with one or a plurality of pre-constraining elements 28, that the distance between the light energy conversion layer 50 and the optical arrangement 40 is constant over the whole device. The pre-constraining elements 28 can for instance be springs or leaf springs. The number of sliders 27 is typically at least three in the direction of movement of the actuator 25 and increases with the size/surface of the panel. In order to accommodate a plurality of sliders 27, the first optical layer 41 of the optical arrangement 40 can be made of several blocks as illustrated in FIG. 20.
[0154] The sliders 27 can slide directly on the surface of one of the layers of the optical system 1, i.e. either the optical arrangement 40 or the light energy conversion layer 50, if necessary with the addition of a coating to reduce friction, or according to a further embodiment of the present invention they can slide on flat or curved sliding pads 29, as shown in FIG. 21. The curvature of the sliding pads 29 can be used to change the distance between the light energy conversion layer 50 and the optical arrangement 40 when the translation element 65 is moved laterally. This is advantageous since with the adaptation of the distance between the optical arrangement 40 and the light energy conversion layer 50, the light energy conversion elements 51 can be brought at the focal point of the primary optical elements 47.
[0155] FIG. 22 shows another embodiment of the present invention, where a gutter 17 is attached to the frame of the device 100. The gutter collects rain 70 falling on the front surface of the device and distribute collected water 71 to the plants below. This is advantageous to avoid depriving plants below the device of rainwater and the need for artificial irrigation.
[0156] FIG. 23 illustrates that the device 100 can comprise a feedback loop based on a light or a temperature sensor at ground level. The processor can retrieve the measured values from the sensor and shift the light conversion layer accordingly to either increase or decrease the amount of light transmitted through the device 100.
[0157] As shown in FIG. 24, multiple devices 100 can be combined in a system. Each of the devices 100 can be configured to transmit more or less light. This is advantageous for instance to have different light intensities on different ground areas/different types of crops, or in order to change the average light transmission over the whole installation.
[0158] FIG. 25 is an exemplary light transmission plot of a device 100 according to the present invention over a complete year, with the average daily light flux on the vertical axis and months on the horizontal axis. The dashed line A indicates the typical light need of an arbitrary type of crop during its growth season (dotted area). The vertical arrows highlight how the light transmission of the device 100 can be increased to match the light requirements of the crop during specific periods of the year.
[0159] Although the present disclosure has been described with reference to particular means, materials and embodiments, one skilled in the art can easily ascertain from the foregoing description the essential characteristics of the present disclosure, while various changes and modifications may be made to adapt the various uses and characteristics as set forth in the following claims.
TABLE-US-00001 Reference numbers 10 frame element 15 flexible membrane 17 gutter 25 actuator 26 guiding element 27 sliders 28 pre-constraining element 29 sliding elements 40 optical arrangement 41 first optical layer 42 second optical layer 43 third optical layer 44 fourth optical layer 45 adhesive layer 47 primary optical element 48 secondary optical element 49 tertiary optical element 50 light energy conversion layer 51 light energy conversion element 52 light scattering layer 53 connection lines 54 light emitting elements 55 quaternary optical elements 56 light shaping element 57′, 57″, 57′″ light diffusing elements 58 encapsulating layer 59′, 59″ first and second protective layers 60 shifting mechanism 65 translation element 70 rain 71 distributed water 80 incident light 81 highly-directional component of incident light 82 diffuse component of incident light 83 focused highly-directional component of incident light 90 transmitted light 91 highly-directional transmitted light 92 diffuse transmitted light 100 device
