EP2929571A2

EP2929571A2 - Optical energy transmission system

Info

Publication number: EP2929571A2
Application number: EP13802582.0A
Authority: EP
Inventors: Adolf Giesen; Stephan Anders; Hans-Albert Eckel
Original assignee: Deutsches Zentrum fuer Luft und Raumfahrt eV
Current assignee: Deutsches Zentrum fuer Luft und Raumfahrt eV
Priority date: 2012-12-07
Filing date: 2013-12-05
Publication date: 2015-10-14
Also published as: DE102012111978A1; US9985157B2; US20160005907A1; WO2014086911A3; WO2014086911A2

Abstract

In order to improve an optical energy transmission system, comprising an energy-emitting unit, which has a laser radiation source for generating an energy-transmitting laser beam and an aiming device for aligning the energy-transmitting laser beam relative to an energy-receiving unit which the energy transmission system comprises and which comprises an optical/electrical converter, which converts the energy of the energy-transmitting laser beam directly into electrical energy, the improvement being such that, firstly, despite high optical power, the thermal destruction thresholds of the photovoltaic elements used are not reached and, secondly, laser safety is ensured, it is proposed that the converter has at least one converter element having a plurality of areas which reflect the energy-transmitting laser beam impinging on said converter element and which are arranged relative to one another such that the impinging energy-transmitting laser beam is deflected by one of the reflective areas to another of the reflective areas, and that at least some of the reflective areas are formed in each case by a conversion unit which reflects one part of the impinging laser beam and absorbs the other part thereof in a photovoltaic element which the conversion unit comprises, and in the process converts the optical energy directly into electrical energy.

Description

OPTICAL ENERGY TRANSMISSION SYSTEM

The invention relates to an optical energy transmission system, comprising an energy emitting unit, the laser radiation source for

Generating an energy-transmitting laser beam and a target device for aligning the energy-transmitting laser beam relative to a energy-receiving system comprising the energy-receiving unit comprising an optical / electrical converter, which converts the energy of the energy-transmitting laser beam directly into electrical energy.

Such energy transmission systems are known in principle from the prior art, wherein the known converter consists of a photovoltaic element, which converts the optical energy of the energy-transmitting laser beam directly into electrical energy.

On the one hand, problems arise here in that the thermal damage threshold of the photovoltaic element must not be exceeded and, on the other hand, to the effect that the laser safety is not permanently guaranteed, in particular when the energy-transmitting laser beam is reflected.

The invention is therefore based on the object to improve an optical energy transmission system of the generic type such that, on the one hand despite high optical performance, the thermal damage thresholds of the photovoltaic elements used are not achieved and on the other hand, the laser safety is guaranteed.

This object is achieved in an optical energy transmission system of the type described above according to the invention in that the converter at least one converter element with a plurality, the on this having incident energy-transmitting laser beam reflecting surfaces which are arranged relative to each other so that the incident energy-transmitting laser beam is deflected from one of the reflective surfaces to another of the reflective surfaces and the at least some of the reflective surfaces are each formed by a conversion unit which detects the incident laser beam partly reflected and partly absorbed in a photovoltaic element encompassed by the conversion unit, thereby converting the optical energy directly into electrical energy.

On the one hand, the advantage of the solution according to the invention is that the laser safety can be ensured by the use of a plurality of reflecting surfaces and, on the other hand, by the fact that some, that is to say at least two, of the reflecting surfaces are in each case one

Conversion unit are formed, which reflect the incident laser beam in part, but implement the other part directly into electrical energy. This makes it possible to use several photovoltaic elements to convert the energy of the incident laser beam directly into electrical energy and thus to achieve that despite high energy of the energy-transmitting laser beam, the damage threshold of the individual photovoltaic elements is not reached.

It has proven to be particularly advantageous if at least three of the reflective surfaces of the converter are formed by a conversion unit.

In order to work with great energy in the energy-transmitting laser beam, it has proven to be advantageous if the converter has at least one converter element whose reflective surfaces are formed by more than three, preferably more than five conversion units.

With regard to the design of the conversion units, no further details have been given so far. In principle, one formed only from a photovoltaic element

Conversion unit with non-normal incidence of a laser beam a non-zero degree of reflection and a non-zero

Absorption coefficient.

However, in order to make an adjustment of the reflectance and the degree of absorption, it is preferably provided that the respective conversion unit, the photovoltaic element and one on a

Having radiation entrance surface of the photovoltaic element arranged reflection-determining coating.

With such a reflection-determining coating, the reflectance and the degree of absorption of each conversion unit can be defined and optionally determined individually.

Regardless of the respective reflection-determining coating, the degree of reflection and the degree of absorption of the angle of incidence of the energy-transmitting laser beam on the reflection-determining

Be dependent on coating, so that it may be necessary in this case, the respective reflective surface and the energy-transmitting laser beam to align relative to each other so that a certain angular range is maintained for the angle of incidence.

For example, in a solution according to the invention, it is provided that the converter is designed so that the energy-transmitting laser beam impinges on the first reflecting surface at an angle of incidence which is 80 ° or less, preferably the angle of incidence is chosen to be 60 ° or less ,

Furthermore, a minimum size of the impact angle is advantageous. For this reason, it is provided in an advantageous embodiment that the converter is formed so that the energy-transmitting laser beam impinges on the first reflective surface in an incident angle which is 10 ° or more, preferably 30 ° or more.

With regard to the reflectance and the degree of absorption of the conversion units of a converter, no further details have been given so far.

Thus, a particularly simple solution provides that all conversion units of a converter element have the same degree of reflection and absorption.

Alternatively, however, it is advantageous, in particular in the case of more than two or three conversion units, for the conversion units applied successively by the laser beam to have a different one

Reflectance and absorption have.

Such a different degree of reflection and absorption can be adjusted so that on the one hand the thermal damage threshold of the respective photovoltaic element is not reached, but on the other hand, with as few conversion elements, a substantially complete absorption of the energy-transmitting laser beam can be achieved.

This objective can be achieved preferably by the fact that, in the successive conversion units acted upon by the energy-transmitting laser beam, the degree of reflection in the order of application of the same by the energy-transmitting laser beam decreases and the degree of absorption increases. If it is assumed that after a number of N reflections on conversion units according to the invention, the energy of the energy-transmitting laser beam is almost zero after the last reflection, the degree of absorption of successive conversion units must be selected according to the following series:

1 / n, 1 / (n-1), 1 / (n-2), 1/2, 1.

The reflectivities corresponding to the degrees of absorption shall be chosen according to the following series:

(n-1) / n, ((n-1) -l) / (n-1), ((n-1) -2) / (n-2) ... 0

This series of absorptions can be further generalized in the following series for the absorptivity: l / (n + m), l / (nl + m), l / (n-2 + m), ... l / ( l + m) and the following series for the reflectance:

((n + m-1)) / (n + m), ((n + m-1) -l) / (n-1 + m), ((n + m-1) -2) / (n-2 + m) ...

((n + m-1) - (n-1)) / (1 + m).

In this case, after the nth reflection, the m / (n + m) th part of the incident energy or power is then reflected by the last reflecting surface. This part can now be directed into an optical sump, or it is possible to completely absorb this part by perpendicularly impinging on a photovoltaic element in this or reflect this part back and then to absorb in the other conversion units in the return.

With regard to the structure of the converter element in detail, no further details have been given so far. Thus, an advantageous solution provides that the reflective surfaces reflect the energy-transmitting laser beam in such a way that it extends in total in two spatial directions in the converter element.

Alternatively, it is conceivable that the reflective surfaces reflect the energy-transmitting laser beam in such a way that it extends in total in three spatial directions in the converter element.

With regard to the orientation of the reflective surfaces in the converter element relative to the energy-transmitting laser beam, no further details have been given so far.

In principle, arbitrary orientations would be conceivable.

In order to obtain favorable conditions as possible, it is preferably provided that the reflecting surfaces of the converter element at an angle in the range between 30 ° and 60 °, preferably in a range between 40 ° and 50 °, to each incident on this section of the energy-transmitting laser beam run.

Furthermore, an advantageous solution provides that the converter element is constructed in such a way that it reflects the energy-transmitting laser beam back into itself after reflection at a plurality of reflective surfaces.

This solution has the advantage that the requirements for laser safety can be met in a simple manner, since this ensures that a laser beam which emerges again from the converter element runs back to the energy-emitting unit and can not be reflected uncontrollably in the room.

A simple solution to achieve this provides that the converter element comprises a triple prism which reflects the laser beam back into itself. Alternatively, another solution provides that the converter element substantially completely absorbs the energy-transmitting laser beam after reflection at a plurality of reflective surfaces by the last conversion unit. In this case, the laser safety is also ensured in a simple manner.

With regard to the design of the target device, no further details have been given in connection with the embodiments explained so far.

Thus, an advantageous solution provides that the target device comprises a target controller which controls the alignment of the energy-transmitting laser beam relative to the energy-receiving unit.

With this target control, it is preferably ensured that the laser safety is ensured, in particular that the energy-transmitting laser beam does not hit other objects not intended for energy transmission.

Furthermore, an advantageous embodiment provides that the target device has a target detection unit, which comprises a position of an intended for the energy-transmitting laser beam impingement of the energy-receiving unit.

With such a target detection unit, it can be ensured that the laser beam always impinges on the impact area of the energy-receiving unit and does not hit other objects. A particularly advantageous solution provides that the target device detects an impact of the energy-transmitting laser beam on an impact area of the energy-receiving unit and prevents an exit of the energy-transmitting laser beam from the energy-emitting unit when the energy-transmitting laser beam does not impinge on the impact area.

Further features and advantages of the invention are the subject of the following description and the drawings of some

Embodiments.

In the drawing show:

Fig. 1 is a schematic representation of an inventive

Power transmission system;

Fig. 2 is a fragmentary view of a converter of a first embodiment;

Fig. 3 is a section along line 3-3 in Fig. 2;

4 shows a section through a second embodiment of a converter according to the invention;

5 shows a section through a third embodiment of a converter according to the invention;

Fig. 6 is a perspective view of a fourth embodiment

for example, a converter according to the invention;

7 is an illustration of the fourth embodiment of the

converter according to the invention shown in FIG. 6 from a different viewing direction; 8 shows a representation of a radiation profile in the fourth exemplary embodiment of a converter according to the invention;

9 shows a section through a fifth embodiment of a converter according to the invention;

10 is a section through a sixth embodiment of a converter according to the invention and

11 shows a section through a seventh embodiment of a converter according to the invention.

An inventive optical energy transmission system, in FIG. 1, designated as a whole by 10, comprises a unit, designated as a whole by 12, which transmits optical energy or optical power, and a unit, denoted as a whole by 14, which receives the optical energy or power-receiving unit.

The energy-emitting unit 12 in turn comprises a high-energy laser radiation source 20 with an exit aperture 22 which generates a laser beam 24 which is deflected, for example, by a deflection mirror 26 of an intended as a whole with 28 target device and as energy-transmitting laser beam 30 from the energy emitting unit 12 in the direction the power receiving unit 14 propagates.

Alternatively, it is also conceivable, for aligning the laser beam 30, the entire laser radiation source 20 or, for example, in a fiber laser, only a component of the laser radiation source 20 from which the laser beam 30 exits align arranged. The aiming device 28 in turn comprises a target controller 32, which controls the position of the deflection mirror 26 in order to make the energy-transmitting laser beam 30 impinge on the desired location of the energy-receiving unit 14.

For this purpose, the target controller 32 preferably also comprises a target detection unit 34, which determines within a detection range 36 the position of an impact area 38 of the energy-receiving unit 14 on which the energy-transmitting laser beam 30 is to occur.

For example, the target detection unit 34 operates either by means of optical scanning of the detection area 26 for detecting the impact area 38 or by means of optical and / or electronic or electromagnetic scanning of the detection area 36 in order to precisely detect the position of the impact area 38 within the detection area 36.

After exact detection of the position of the impact area 38 relative to the energy emitting unit 12 is carried out by the target controller 32, the alignment of the energy-transmitting laser beam 30 in space by means of in all

Spatial directions of movable deflecting mirror 26 such that the energy-transmitting laser beam 30 impinges within the impact region 38 of the energy-receiving unit 14.

Furthermore, in a variant of the target device 28, the target detection unit 34 detects whether the energy-transmitting laser beam 30 actually impinges on the impact area 38, for example by back reflection of the laser beam 30 from the impact area 38 or by the laser beam 30 induced

secondary emission of radiation from the impact area 38.

If an impact of the energy-transmitting laser beam 30 on the impact area 38 is detected in this variant of the target device 28, either the exit diaphragm 22 is closed by the target device 28 and / or the laser radiation source 20 is switched off or out of adjustment so that the energy-transmitting laser beam 30 can no longer escape from the energy-emitting unit 12.

In the energy-receiving unit 14, the impact area 38 is formed by an inlet opening 42 of an optical / electrical converter 44, which converts the energy or power contained in the energy-transmitting laser beam 30 directly into electrical energy, so that either directly by the converter 44 or a current / voltage -Wanderer unit 46 at an electrical connection 48, a voltage U is available.

The converter 44 may be formed in various ways.

A first embodiment of a converter according to the invention, shown in FIG. 2, comprises as a converter element as a whole with 60

designated triple prism, which is formed by three, each extending at an angle of 90 ° to each other reflective surfaces 62i, 62 ₂ and 62 ₃ , which intersect at a vertex 64.

From such a corner cube prism 60 of the incident portion 30e of the power transmitting laser beam 30, when it strikes the reflecting surface 62i, first as a first reflected portion 30n reflected on the reflecting surface 62 ₂ and 30 _r2 there reflective of this as a second reflected portion of the Surface 62 _{3 is} reflected and then exits after a three-dimensional course in the triple prism 60 as outgoing laser beam 66 again from the triple prism 60, the essential characteristic of the triple prism 60 is that the exiting laser beam 66 parallel to the incident portion 30 _{e of} the energy transmitting laser beam 30th is aligned, but runs in the opposite direction. As shown in FIG. 3, each of the reflective surfaces 62 of the triple prism 60 is formed by a photovoltaic element 70 whose

Radiation incident surface 72 either immediately forms the reflective surface 62 or is still provided with a coating 74 which forms the reflective surface 62.

The reflecting surface 62 is not a completely reflecting surface, but a partially reflecting surface, so that a part of the energy or power of the energy transmitting laser beam 30 is absorbed by the photovoltaic element 70 and generates therein a current which is supplied via electrical connections 76 of the photovoltaic element 70 can flow.

The photovoltaic element 70 with its radiation incident surface 72 and optionally the reflection co-determining coating 74 thus forms a conversion unit 80 for the energy-transmitting laser beam 30, which absorbs a significant portion of the energy of the incident energy-transmitting laser beam 30 and converts directly into electrical energy.

If, for example, half of the energy of the impinging laser beam 30 is absorbed by the conversion unit 80 and the other half is reflected, the first reflected portion 30n of the energy-transmitting laser beam 30 strikes the reflective surface 62 ₂ with half the reduced energy.

If the reflecting surface 62 _{2 is formed} by a conversion unit 80 ₂ , which is constructed in the same way as the conversion unit 80i and has the same reflectance, then half of the energy is absorbed by the first reflected portion 30n of the energy transmitting laser beam 30 and half reflected such that in turn the second reflected portion 30 _{r2 of} the energy transmitting laser beam 30 has an energy which is only one quarter of the energy of the incident one

Section 30 _{e of} the energy-transmitting laser beam 30 originally had prior to hitting the converter 44. If the reflecting surface 62 is formed ₃ by a conversion unit 80 _3, which is constructed in the same manner as the reflecting unit 80i, so in turn half of the energy of the second reflected portion 30 _r2 of the power transmitting laser beam 30 is absorbed, and reflects the other half, such that the precipitating portion 66 of the energy transmitting laser beam 30 still has the energy of one eighth of the energy of the incident portion 30 _{e of} the energy transmitting laser beam 30.

However, if the reflectance of the reflective conversion units 80i to 80 _{3 is} reduced, for example, to one third, the energy of the emergent laser beam 66 continues to be reduced in relation to the incident portion 30 _{e of} the energy-transmitting laser beam 30.

In the first embodiment of the converter 44 according to the invention with reflecting surfaces 62 arranged corresponding to the triple prism 60, it is also possible to align the energy-transmitting laser beam 30 so that it exactly meets the corner point 64 with its center axis, so that the same conditions exist in this case, However, each of the reflective surfaces 62 is directly acted upon by a portion of the incident portion 30 _{e of} the energy transmitting laser beam 30 and then this part is then further reflected on the other reflective surfaces 62, so that each part of the energy transmitting laser beam 30 again after three times as precipitating portion 66 of the laser beam 30 parallel to the incident portion 30 _{e of} the energy transmitting laser beam 30 propagates.

In the first exemplary embodiment according to FIGS. 2 and 3, the impact area 38 is defined by the entrance opening 42 of a single triple prism 60, so that an exact alignment of the energy-transmitting laser beam 30 relative to the energy-receiving unit 14 must take place on the part of the target detection unit 34 and the target control 32. In order to keep the requirements for the target controller 32 lower, but there is also the possibility of the impact region 38 that this to 42 _n is formed _n of triple prisms 60i to 60 by a plurality of inlet openings 42i, which are all directly in two dimensions to increase by adjacent to a surface FP and are arranged with the same orientation to this, so that regardless of which serving as converter elements triple prisms 60i to 60 _{n is} acted upon by the energy transmitting laser beam 30, there is always the possibility of the energy of the energy transmitting laser beam 30 with the same efficiency.

The second exemplary embodiment of the converter 44 'according to the invention can be used, for example, if a large-area converter 44' with a correspondingly large impact area 38 'is to be available in order, for example, not to make the requirements for the target controller 32 and the target detection unit 34 too great.

", In a third embodiment of a converter 44 according to the invention an arrangement of conversion units 80 are provided in a converter element, for example, the incident portion exceeds 30 _e of the power transmitting laser beam 30 to a first reflecting surface 92i, then in the form of a first reflected portion 30n to a second reflecting surface 92 _{2 occurs} , then in the form of a second reflected portion 30 _r ₂ on a third reflecting surface 92 ₃ finally in the form of a third reflecting portion 30 _r ₃ on a fourth reflecting surface 92 ₄ occurs, for example, all these surfaces are flat reflecting surfaces, and finally, in the form of a fourth reflected portion 30 _{r4, impinges} on a triple _prism 60 " _having the reflective surfaces 92 ₅ , 92 ₆ and 92 ₇ .

All reflecting surfaces 92i to 92 ₇ are associated with conversion units 80i to 80 ₇ , as they were explained in connection with the first embodiment. The triple prism 60 "causes the energy transferring laser beam 30 multiply reflected before striking the triple prism 60" by this triple prism 60 "to be reflected on the reflective surfaces 92 ₄ , 92 ₃ , 92 ₂ and 92i, and then as the failing section 66 the converter 44 "leaves again, but with an energy that is significantly lower than the energy of the incident energy-transmitting laser beam 30th

In the third embodiment, however, it is also possible, only in some, not in all reflective surfaces 92i to 92 ₄ by a

Conversion unit 80 perform the direct conversion of optical energy into electrical energy, with a photovoltaic element 70 to realize, and in cases where a reflection for beam deflection is required to form one or more of the reflective surfaces 92 as fully reflective surfaces.

In order to reduce the energy of the energy-transmitting laser beam 30 as far as possible to the impact on the triple prism 60 ", the transmissions and reflection of the coatings 74 of the individual can

Conversion units 80 vary.

For example, can be adjusted, the reflection so that one-fifth of the energy of the incident portion is absorbed 30 _e of the power transmitting the laser beam 30, the reflection can be adjusted as in the conversion unit 80 _2, a quarter of the energy of the reflected portion 30n in the conversion unit 80i In the conversion unit 80 ₃ , the coating 74 is set so that one third of the energy of the reflected portion 30 _{r2 is} absorbed, in the conversion unit 80 ₄ , the coating 74 is set so that half the energy of the reflected portion 30 _r3 is absorbed and in all conversion units 80 ₅ to 80 ₇ , the coating 74 is formed so that the entire existing energy in the reflected portion 30 _{r4 is absorbed} by the conversion _units 80 ₅ to 80 ₇ , so that of the triple prism 60 "returning laser beam 30 has substantially no energy.

A fourth exemplary embodiment of a converter 44 "'according to the invention is shown in FIGS. 6 to 8.

In this case, the converter 44 "" is formed by a spatial arrangement of reflective surfaces 102 in a converter element 100, which are arranged in a compact manner, for example in an outer geometry corresponding to a cube W, the cube being composed of eight sub-cubes UW and the reflecting surfaces 102 are arranged according to diagonal surfaces of the sub-cubes.

The eight sub-cubes UWi to UW _{8 of the} same size are arranged as follows.

A first sub-cube layer lying on a base G comprising the sub-cubes UWi, UW ₂ , UW ₃ and UW _{4 is} formed, all of which are arranged adjacent to each other within the square outer geometry in a counterclockwise sequence. On this sub-cube layer from the sub-cubes UWi to UW ₄ is a second sub-cube layer of the sub-cubes UW ₅ to UW ₈ which are also arranged adjacent to each other within the square outer geometry and in a counterclockwise direction, the sub-cube UW ₅ on the sub-cube UWi, the Sub-cube UW ₆ on the sub-cube UW ₄ , the sub-cube UW ₇ on the sub-cube UW ₃ and the sub-cube UW ₈ on the sub-cube UW ₄ .

The sub-cubes UW ₂ and UW ₆ are provided with a reflection plane REi passing through both sub-cubes UW ₂ and UW ₆ , which extends along the same diagonal of both sub-cubes UW ₂ and UW ₆ and extends parallel to a first reflector direction RRi. In addition, the sub-cube UW ₃ and UW ₇ are provided with an opening through both of sub-cube UW ₃ and UW ₇ reflection plane RE _2, which also runs parallel to the first reflector direction RRi and along the same diagonal of sub-cube UW ₃ and UW ₇ and perpendicular to the reflection plane rei, wherein the reflection planes REi and RE _{2 are} facing the sub-cubes UWi and UW ₄ as well as UW ₅ and UW ₈ .

Furthermore, the sub-cubes UW ₈ and UW _{5 are provided} with a reflection plane RE ₃ , which runs along a common diagonal of these sub-cubes UW ₈ and UW ₅ parallel to a reflector direction RR ₂ , which in turn is perpendicular to the reflector direction RRi.

The sub-cube UW ₄ is provided with a reflection plane RE ₃ which is parallel to the reflector direction RR ₂ and to a diagonal of the sub-cube UW ₄ and perpendicular to the reflection plane RE ₄ , the reflection plane RE ₃ facing the sub-cubes UW ₃ and UW ₇ and the reflection plane RE ₄ faces the sub-cubes UW ₂ and UW ₃ as well as UW ₆ and UW ₇ .

An incidental energy-transmitting laser beam 30 passing centrally through the first sub-cube UWi with its optical axis passes through the sub-cube UWi without reflection and strikes the first reflecting surface 102i which lies in the sub-cube UW ₂ in the reflection plane REi.

From this reflecting surface 102i, the laser beam 30 is reflected as the first reflecting portion 30n on the second reflecting surface 102 ₂ in the reflecting plane RE _{2 located} in the sub-cube UW ₃ and the laser beam 30 in the form of the second reflecting portion 30 _r2 the third reflecting surface 102 _{3 is} reflected in the reflection plane RE ₃ , which in the

Subcube UW ₄ is located, which in turn reflects the laser beam 30 in the form of the third reflected portion 30 _r3 on the lying in the reflection plane RE ₄ fourth reflection surface 102 ₄ , the laser beam 30 in the form of the fourth reflected portion 30 _r4 again to the fifth reflective Surface 102 ₅ reflected, which lies in the reflection plane RE ₂ . From there In turn, a reflection of the laser beam 30 in the form of the fifth reflected portion 30 _r5 on the reflective surface 102 ₆ , ie the U in the U U ₆ erie in the reflection plane REI in U Uter and from this there is a reflection of the laser beam 30 in the form of the sixth reflected portion 30 _r6 on the reflective surface 102 ₇ , which in the reflection plane RE ₄ in U nterwü cube UW ₅ lgt. From this, a reflection of the laser beam 30 takes place in the form of the seventh reflected portion 30 _r7 on an end face 102 ₈ d he Uwe in U nterwü cube and coincides with the base G.

Al le reflective surfaces 102i to 102 ₈ are formed by a conversion ^¬ unit 80, as described in connection with Fig .3.

Also in this embodiment it is possible to vary the reflectivity of the conversion unit 80 to the conversion unit 80 so that, for example, the coating 74 is set such that one-eighth of the energy of the conversion unit 186 of the reflecting surface 102i is present energy absorbing laser beam 30 is absorbed, while from the reflective surface 102 ₂ zugeord Neten reflective unit 80 one seventh of the energy of the laser beam 30 is absorbed.

In general, the following series for the absorption in the conversion units 80 associated with the successive reflecting surfaces 102 can be set up for this purpose. The Absorptionsg rad of the individual nen successive conversion units 80 results in the following series

1 / n, 1 / (n-1)..., 1/2, 1 where nd is the number of conversion units 80 acted upon by the energy-transmitting laser beam 30. In a fifth exemplary embodiment of a converter 44 "" according to the invention, illustrated in FIG. 9, a converter element 110 divides the incident energy-transmitting laser beam 30 into two cells 110a and 110b, each of which has a first reflective surface 112ai and 112bi, which in FIG an angle of 45 ° to a propagation direction of the incident energy-transmitting laser beam 30 are.

This first reflecting surface 112ai and 112bi reflects each of the incident portion 30 _e of the power transmitting laser beam 30 to a second reflecting surface 112a ₂ and 112b ₂ which is parallel to the first reflecting surface 112ai and 112bi, is arranged, however, offset from.

The second reflecting surface 112a ₂ or 112b ₂ reflects the first reflected portion 30n of the laser beam 30 incident thereon as a second reflected portion 30 _r2 onto a third reflecting surface 112a ₃ or 112b ₃ and reflects the second reflecting portion 30 incident thereon _r2 as the third reflected portion 30 _r3 onto a fourth reflecting surface 112a ₄ and 112b ₄ , which is in turn arranged parallel to the second reflecting surface 112a ₂ and 112b ₂ , respectively, and in turn to the third incident portion 30 _r3 as the fourth reflecting portion 30 _r4 fourth reflecting surface 112a ₅ and 112b ₅ , respectively, which is disposed on a back side of the respective first reflecting surface 112ai and 112bi and reflects the fourth reflected portion 30 _r4 as a portion 30 ₅ on the surface 112a ₆ and 112b ₆ , respectively either fully absorbed the fifth reflected portion 30 ₅ or possibly still reflected.

In this embodiment as well, each of the reflective surfaces 112 is formed by a conversion unit 80, the coating 74 of which reflects part of the energy of the laser beam 30 and allows part of the energy of the laser beam 30 to enter the photovoltaic element 70 in order to direct the optical energy into it to convert electrical energy. Preferably, in the fifth embodiment, all the reflective surfaces 112ai to 112a are ₅ or 112bi to 112b ₅ at 45 ° to

The propagation direction of the incident energy-transmitting laser beam 30, wherein the reflective surfaces 112ai and 112a ₅ and 112bi and 112b ₅ abut each other and relative to the reflective surfaces 112a ₂ and 112a ₄ , and 112b ₂ and 112b ₄ , which are parallel to the reflective surfaces 112ai and 112a ₅ and 112bi and 112b ₅ are offset so that the reflective surfaces 112a ₂ and 112b _{2 make} the incident energy-transmitting laser beam 30 with its entire beam diameter D impinge unimpeded on the reflective surfaces 112ai and 112bi, but on the other hand from that of the reflective Surfaces 112ai and 112bi reflect full-section reflected portion 30n onto the reflective surface 112a ₃ and 112b ₃ , respectively, which are perpendicular to the reflective surfaces 112ai and 112b ₂ . The reflective surfaces 112a ₃ and 112b ₃ , for their part, again run perpendicular to the reflective surfaces 112a ₄ and 112b ₄ , so that they in turn further reflect the reflected section 30 ₃ with a full cross section onto the reflective surfaces 112a ₅ and 112b _5, respectively.

In a variant of the fifth embodiment according to FIG. 9, however, it is also possible to omit the reflecting surfaces 112a ₆ and 112b ₆ , so that the reflected section 30 _{r5 can pass} from the cell 110a or 110b the respective other cell 110b or 110a and can travel through it in the opposite direction.

In a sixth exemplary embodiment of a converter 44 '''according to the invention, shown in FIG. 10, conversion units 80 _a i to 80 _{a are} provided successively in a row direction R _a , the surfaces lying in a common area F, in particular in a common plane, reflecting surfaces 122ai to 122a ₆ , have. These reflective surfaces 122a 122ai to ₆ opposite a substantially fully reflective surface 122b is provided, which the reflecting surfaces 122a to 122ai ₆ facing and spaced therefrom, and preferably parallel thereto, and another reflective surface 122c which extends transversely, particularly perpendicular, to both the reflective surfaces 122a and the reflective surface 122b.

The reflecting surfaces 122ai to 122a ₆ are formed by partially reflecting coatings 74i to 74 _{6 of} the conversion units 80ai to 80a ₆ whose reflectance varies.

Each of the coatings 74i to 74 ₆ is arranged on a single photovoltaic element 70, wherein each of the coatings 74i to 74 ₆ covers a portion of the photovoltaic element and forms a conversion unit 80i to 80 ₆ with this portion.

With the variation of the reflectance of the reflective coatings 74i to 74 ₆ also vary the degrees of absorption of this conversion units 80i to 80 ₆ wherein the absorption coefficients are adjusted so that the 74i of the respective coating to 74 ₆ covered partial area of the photovoltaic element 70 is approximately the same intensity of the laser radiation absorbed like the remaining portions of the photovoltaic element 70.

In the sixth embodiment of the converter 44 "", the incident energy-transmitting laser beam 30 first strikes and is reflected by the reflective surface 112ai to form the first reflected portion 30ri incident on the reflective surface 122b, while in the conversion unit 80ai the unreflected part of the intensity is absorbed. This substantially completely reflects the first reflected portion 30ri so that a reflected portion 30r _{2 is} incident on the reflecting surface 122a ₃ , and from this part of the intensity is reflected while the non-reflected part of the intensity of the reflecting layer 74a ₃ supporting conversion unit 80a _{3 is} absorbed.

The third reflected portion 30 _r3 again strikes the reflecting surface 122b and is substantially completely reflected by it, so that a fourth reflected portion 30 _{r4 strikes} the reflecting surface 122a ₅ , part of the intensity reflecting and part of the intensity is absorbed by the conversion unit 80a ₅ .

The fifth reflected portion 30 _r5 again strikes the reflecting surface 122b, is reflected by this substantially completely as the sixth reflected portion 30 _r5 , strikes the reflecting surface 122c, and is substantially completely reflected by this seventh reflecting portion 30 _r7 that it hits the reflective surface 122a ₆ . From this part of the intensity is reflected and a part of the intensity in the conversion unit 80a _{6 is} absorbed.

The reflected portion 30 _r8 then strikes the reflective surface 122b and is reflected by it as a reflected portion 30 _r9 and strikes the reflective surface 122a ₄ . From this part of the intensity is reflected as a reflected portion 30 _rl o and a part of the intensity is absorbed by the conversion unit 80 a ₄ . The reflected portion 30 _rl o applies to the reflected surface 122b and _r u reflected therefrom as a reflected portion 30 so that it strikes the reflecting surface 122a _2, wherein absorbs a part of the intensity from the conversion unit 80a ₂ and a portion as reflected portion 30n _{2 is} reflected, however, as little, if not no more intensity, has. Because the conversion units 80ai to 80a ₆ each comprise subareas of a photovoltaic element, this embodiment of the converter according to the invention is particularly simple and inexpensive to produce.

In a seventh embodiment of a converter 44 '''according to the invention shown in Fig. 11, the arrangement and operation of the reflective surfaces 122ai to 122a ₆ , the coatings 74ai to 74a ₆ and the conversion units 80ai to 80a _{6 are} identical to those of the sixth exemplary embodiment.

However, unlike the sixth embodiment, in the seventh embodiment, the reflecting surface 122b is not a fully reflecting surface but is also divided into reflecting surfaces 122bi to 122b ₅ , all of which partially reflect and partially absorb the intensity in each _other in the direction of row R _a parallel row direction R _b disposed conversion unit 80bi to 80b ₅ allow the conversion units are formed 80bi to 80b ₅ by partial areas of the photovoltaic element 70b, and in addition the coatings 70bi to 70b ₅ comprise forming the reflecting surfaces 122bi to 122b. ₅

Thus, the reflected portions 30 _r3 , 30 _r4 , 30 _r8 and 30 _rl o of the individual reflective surfaces 122bi to 122b _{6 are} not completely reflected but only partially reflected, so that in the conversion units 80bi to 80b _{5 is} still a corresponding absorption of intensity ,

The advantage of the seventh embodiment is therefore that the number of conversion units 80 is increased and thus the adjustment of the absorption and reflection levels of the individual coatings 70a and 70b can be made even simpler by the intensity absorbed by the respective conversion units 80a and 80b adapt so that in each conversion unit approximately the same intensity is absorbed. In a further development of the seventh embodiment, it is also possible to provide no individual separate coatings 74ai to 74a ₆ or 74bi to 74b ₅ , but to continuously vary the reflection and absorption of the individual coatings 70a and 74b in the row direction Ra or R _b .

Claims

P A T E N T A N S P R E C H E

An optical energy transfer system (10) comprising an energy emitting unit (12) including a laser radiation source (22) for generating a power transmitting laser beam (30) and an aiming means (28) for aligning the energy transmitting laser beam (30) relative to a power receiving unit included in the energy transmission system (14) comprising an optical / electrical converter (44) which converts the energy of the energy transmitting laser beam (30) directly into electrical energy,

characterized in that the converter (44) comprises at least one converter element (60, 90, 100, 110) having a plurality of surfaces (62, 92, 102, 112) reflecting the energy transmitting laser beam (30) impinging thereon and being arranged relative to each other in that the incident energy-transmitting laser beam (30) is deflected from one of the reflective surfaces (62, 92, 102, 112) to another of the reflective surfaces (62, 92, 102, 112) and that at least some of the reflective surfaces (62, 92, 102, 112) are each formed by a conversion unit (80) which partially reflects the incident laser beam (30) and, on the other hand, absorbs it in a photovoltaic element (70) encompassed by the conversion unit (80) Convert energy directly into electrical energy.

Energy transmission system according to claim 1, characterized in that the respective conversion unit (80) comprises the photovoltaic element (70) and a on a radiation entrance surface (72) of the photovoltaic element (70) arranged reflection-determining coating (74). An energy transfer system according to claim 1 or 2, characterized in that the converter (44) is formed so that the energy transmitting laser beam (30) impinges on the first reflecting surface (62i, 92i, 102i, 112i) at an angle of incidence equal to 80 ° or less.

Energy transmission system according to one of the preceding

Claims, characterized in that all conversion units (80) of a converter (44) have the same degree of reflection and absorption.

Energy transmission system according to claim 1 to 3, characterized in that the succession of the laser beam (30) acted upon conversion units (80) have a different degree of reflection and absorption.

Energy transmission system according to claim 5, characterized in that in the succession of the energy-transmitting laser beam (30) acted upon conversion units (80), the reflectance in the order of their application by the energy-transmitting laser beam (30) decreases and the absorption coefficient increases.

Energy transmission system according to one of the preceding

Claims, characterized in that the reflective surfaces (62, 92, 102, 112) reflect the energy transmitting laser beam (30) so that it extends in total in two spatial directions in the converter element (60, 90, 100, 110).

8. Energy transmission system according to one of the preceding

Claims, characterized in that the reflective surfaces (62, 92, 102, 112) reflect the energy transmitting laser beam (30) so that it extends in three spatial directions in the converter element (60, 90, 100, 110).

9. Energy transmission system according to one of the preceding

Claims, characterized in that the reflecting surfaces (62, 92, 102, 112) of the converter element (60, 90, 100, 110) at an angle in the range between 40 ° and 50 ° to the each incident on this section (30i to 30 _n ) of the laser beam (30).

10. Energy transmission system according to one of the preceding

Claims, characterized in that the converter element (60, 90) is constructed so that this reflects back the energy-transmitting laser beam (30) in itself after reflection at a plurality of reflective surfaces (62, 92).

11. Energy transmission system according to claim 10, characterized in that the converter element (60, 90) comprises a laser beam (30) in itself reflecting back triple prism (60).

12. Energy transmission system according to one of the preceding

Claims, characterized in that the converter element (100, 110) the laser beam (30) after reflection at a plurality of reflective surfaces (102, 112) by the last conversion unit (80) in

Essentially completely absorbed.

13. Energy transmission system according to one of the preceding

Claims, characterized in that the aiming device (28) comprises a target controller (32) which controls the alignment of the energy transmitting laser beam (30) relative to the energy receiving unit (14).

14. Energy transmission system according to one of the preceding

Claims, characterized in that the aiming device (28) comprises a target detection unit (34) which detects a position of an intended for the energy-transmitting laser beam (30) incidence region (38) of the energy-receiving unit (14).

15. Energy transmission system according to claim 14, characterized in that the target detection unit (34) within a

spatial detection area (36) detects the position of the impact area (38).

Energy transmission system according to one of the preceding

Claims, characterized in that the target device (28) detects an impact of the energy-transmitting laser beam (30) on an impingement region (38) of the energy-receiving unit (14) and prevents an exit of the energy-transmitting laser beam (30) from the energy-emitting unit (12), when the energy transmitting laser beam (30) does not impinge on the impingement area (38).