Oval-condenser zoom with independent axis adjustment

Abstract

The invention relates, inter alia, to a light fixture (10) for illuminating building surfaces (17) or partial building surfaces, comprising a housing (11), at least one light source, in particular an LED (12, 12a, 12b, 12c), and at least one collimating optics, in particular collimating optics (15, 15a, 15b, 15c) for collimating the light emitted by the light source. A particular feature is that at least three lens plates (18, 19) are provided in the light path behind the collimating optics, on each of which lens plates a plurality of lens elements (22a, 22b, 22c, 23a, 23b, 23c, 69a, 69b, 69c, 70a, 70b, 70c) is arranged, in particular grouped, wherein the relative spacings (32, 75) between one of the two outer lens plates, in each case, and the central lens plate, can be changed by means of at least one adjustment device (20), and wherein the light fixture provides different light distributions (37, 38, 39, 50a, 50b, 50c) in different mutual spacing positions of the lens plates.

Claims

1. A light fixture for illuminating a building surface or part of a building surface, the fixture comprising: a housing, a light source, collimating optics for collimating light emitted by the light source, a first outer lens plate, a second outer lens plate, a central lens plate between the first outer lens plate and the second outer lens plate, the first outer lens plate being between the collimating optics and the central lens plate, a respective group of lens elements on each of the lens plates, the lens elements of the first and second outer lens plates being lenticular lenses or portions thereof, and an adjustment device for changing a relative spacing between one of the outer lens plates and the central lens plate such that the light fixture provides different light distributions in different relative spacings of the first, second, and third lens plates.

2. The light fixture according to claim 1, wherein the adjustment device is a motorized drive for adjusting the spacing.

3. The light fixture according to claim 1, wherein the adjustment device is a manually operable actuator for changing the spacing.

4. The light fixture according to claim 1, wherein the adjustment device has a positioning device for maintaining a relative rotational position between at least two of the first, second, and central lens plates.

5. The light fixture according to claim 1, wherein the different light distributions comprise a first oval light distribution that extends in a first axial direction and a second oval light distribution that extends in a second axial direction perpendicular to the first axial direction.

6. The light fixture according to claim 1, wherein the light fixture provides different oval light distributions in different relative spacings of the lens plates.

7. The light fixture according to claim 1, wherein the adjustment device varies the spacing continuously.

8. The light fixture according to claim 1, wherein one of the first, second, and central lens plates is fixed relative to the housing, and the other two of the first, second, and central lens plates are displaceable relative to the housing or relative to the central lens plate by the adjustment device.

9. The light fixture according to claim 1, wherein the lens elements on the central lens plates have facets.

10. The light fixture according to claim 9, wherein a plurality or all of the facets each have a curvature that is spherical or approximates a sphere, or is formed as a rotational paraboloid.

11. The light fixture according to claim 1, wherein each lenticular lens or portion thereof of the first outer lens plate is oriented with respect to a respective lens element of the central lens plate.

12. The light fixture according to claim 11, wherein an orientation of each lenticular lens or portion thereof of the first outer lens plate relative to a respective lens element of the central lens plate is such that light components emerging from the collimating optics strike one of the lenticular lenses or portion thereof of the first outer lens plate and are directed therefrom only toward respective lens elements of the central lens plate, and light components emitted by lens elements of the central lens plate are directed therefrom only toward respective lens elements of the second outer lens plate.

13. The light fixture according to claim 11, wherein an orientation of each lens element of the first outer lens plate relative to a respective lens element of the central lens plate is maintained when the spacing between the lens plates is changed.

14. The light fixture according to claim 1, further comprising: a positive control means for changing the relative spacing between the second outer lens plate and the central lens plate simultaneously with changing of the relative spacing between the first outer lens plate and the central lens plate.

15. The light fixture according to claim 1, wherein the lenticular lenses on the first outer lens plate extend in a first direction and the lenticular lenses on the second outer lens plate extend in a second direction perpendicular to the first direction.

16. A method for changing light emission characteristics of a light fixture for illuminating a building surface or part of a building surface according to claim 1, the method comprising the steps of: a) providing a light fixture comprising a housing, a light source, collimating optics, and at least three lens plates that are provided in the light path downstream of the collimating optics and each comprising a plurality of lens elements, b) providing adjustment device for adjusting the relative position of one or both of the two outer lens plates with respect to the central lens plate, c) changing the emission characteristics of the light fixture by displacing outer lens plate relative to the central lens plate.

17. A light fixture for illuminating a building surface or part of a building surface, the fixture comprising: a housing, a light source, collimating optics for collimating light emitted by the light source, a first outer lens plate, a second outer lens plate, a central lens plate between the first outer lens plate and the second outer lens plate, the first outer lens plate being between the collimating optics and the central lens plate, a respective group of lens elements on each of the lens plates, a first adjustment device for changing a relative spacing between the first outer lens plate and the central lens plate, and a second adjustment device for independently changing a relative spacing between the second outer lens plate and the central lens plate independently of the relative spacing between the first outer lens plate and the central lens plate.

18. A light fixture for illuminating a building surface or part of a building surface, the light fixture comprising: a housing, a light source, collimating optics for collimating the light emitted by the light source, a plurality of lens elements on the collimating optics, two lens plates in the light path behind the lens elements, a plurality of spaced lens elements on each of the lens plates, a first adjustment device for changing a spacing between one of the lens plates and the collimating optics, and a second adjustment device for changing a spacing between the two lens plates such that the light fixture provides different light distributions in different spacing positions of the lens plates from the collimating optics.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) Further advantages of the inventions can be found in the dependent claims (not cited), and with reference to the following description of the numerous embodiments shown in the figures.

(2) In the figures:

(3) FIG. 1a is a partially cut away block diagram-like view of a first embodiment of a light fixture according to the invention having a light drive comprising an LED and a collimator, and three lens plates that can be adjusted relative to one another by means of two adjustment devices,

(4) FIG. 1b is a schematic, partially cut away view, approximately according to the cutting line Ib-Ib in FIG. 1a, of the light fixture of FIG. 1a,

(5) FIG. 2 is a truncated schematic view from below, approximately along the elevation arrow II in FIG. 1a, of the central lens plate, the relative positions of the light drives being indicated,

(6) FIG. 3 shows a further embodiment of a central lens plate according to the invention, in a view according to FIG. 2,

(7) FIG. 4 is a view according to FIG. 2, approximately along the elevation arrow IV in FIG. 1a, of an embodiment of a first outer lens plate according to the invention, showing lenticular lenses,

(8) FIG. 5 is a partially cut away schematic view of the first outer lens plate, approximately according to the cutting line V-V in FIG. 4,

(9) FIG. 6 is a view comparable to FIG. 4, approximately in accordance with the elevation arrow VI in FIG. 1a, of an embodiment of a second outer lens plate according to the invention,

(10) FIG. 7 is a partially cut away schematic view of the second outer lens plate, approximately along the cutting line VII-VII in FIG. 6,

(11) FIG. 8a is a partially cut away, downscaled schematic view of a detail of the light fixture of FIG. 1, indicating the adjustment device and the three lens plates in a first maximum spacing position,

(12) FIG. 8b is the detail of the light fixture of FIG. 8a in an arrangement rotated by 90°, approximately along the cutting line VIIIb-VIIIb in FIG. 8a,

(13) FIG. 8c is a schematic view of a building surface to be illuminated, having the light distribution, generated on the building surface by the light fixture of FIG. 8a, according to the spacing position of the two lens plates according to FIGS. 8a and 8b,

(14) FIG. 9a shows the schematic arrangement of FIG. 8a having a changed mutually spacing position between the first outer lens plate and the central lens plate, wherein the spacing between the central lens plate and the second outer lens plate is unchanged,

(15) FIG. 9b is a view according to FIG. 8b of the light fixture according to FIG. 9a,

(16) FIG. 9c is a view according to FIG. 8c of the light distribution in the case of a lens plate spacing according to FIGS. 9a and 9b,

(17) FIG. 10a is a schematic view of the light fixture of FIG. 8a comprising a first outer lens plate and central lens plate that are as close together as possible, while the spacing between the central lens plate and the second outer lens plate is unchanged,

(18) FIG. 10b shows the light fixture of FIG. 10a rotated about 90°, approximately along the cutting line Xb-Xb in FIG. 10a,

(19) FIG. 10c is a view according to FIG. 9c of the light distribution in the event of a spacing position of the lens plates according to FIGS. 10a and 10b,

(20) FIG. 11a, 11b and 11c are views according to FIGS. 8a, 8b and 8c of the light fixtures when the lens plates are at a maximum mutual spacing,

(21) FIGS. 12a, 12b and 12c are views of the light fixtures that correspond to the views of FIG. 11a, 11b and 11c, wherein the spacing between the central lens plate and the second outer lens plate has been reduced, while the spacing between the first outer lens plate and the central lens plate is unchanged,

(22) FIGS. 13a, 13b and 13c are views of the light fixtures that correspond to the views of FIG. 11a, 11b and 11c, wherein the relative spacing between the central lens plate and the second outer lens plate is minimized, while the spacing between the first outer lens plate and the central lens plate is unchanged,

(23) FIGS. 14a, 14b and 14c are views of the light fixtures that correspond to the views of FIGS. 8a, 8b and 8c, wherein in each case a maximum spacing between the central lens plate and the two outer lens plates is achieved,

(24) FIGS. 15a, 15b and 15c are views of the light fixtures that correspond to the views of FIGS. 14a, 14b and 14c, wherein both the relative spacing between the first outer lens plate and the central lens plate, and the spacing between the second outer lens plate and the central lens plate is reduced,

(25) FIGS. 16a, 16b and 16c are views of the light fixtures that correspond to the views of FIGS. 14a, 14b and 14c, wherein the spacing between the first outer lens plate and the central lens plate, and the spacing between the second outer lens plate and the central lens plate is minimized,

(26) FIG. 17 is a view according to FIG. 4 of a further embodiment of a first outer lens plate according to the invention, using lenticular facets,

(27) FIG. 18 is an enlarged schematic detail view of a single lenticular facet according to the partial circle XVIII in

(28) FIG. 17,

(29) FIG. 19 is a partially cut-away view through the facets of FIG. 18, along the cutting line XIX-XIX in FIG. 18,

(30) FIG. 20 is a partially cut-away view through the facets of FIG. 18, along the cutting line XX-XX in FIG. 18,

(31) FIG. 21 is a view according to FIG. 1a of a further embodiment of a light fixture, wherein, in this embodiment, the light drive is provided by a chip on board LED, and a reflector is provided as the collimating optics,

(32) FIG. 22 is a view according to FIG. 1 of a further embodiment of a light fixture according to the invention, wherein in this case, instead of three lens plates, collimating optics comprising lens elements directly attached thereto and two lens plates arranged at a spacing that can be changed relative thereto is provided,

(33) FIG. 23 is a view according to FIG. 4 of a further embodiment of a central lens plate according to the invention, using concentrically arranged annular lenticular lenses,

(34) FIG. 24 is a view according to FIG. 1a of a further embodiment of a light fixture according to the invention, wherein, in a manner different from the view of FIG. 1a, the central lens plate is arranged so as to be rotated by 180° or geometrically inverted, and therefore the lens elements of the central lens plate are turned away from the collimating optics,

(35) FIG. 25 is a partially cut away, truncated, schematic view of a detail of the central lens plate according to FIG. 24, approximately according to the partial circle XXV in FIG. 24, and

(36) FIG. 26 is a view according to FIG. 1a of a further embodiment, wherein the lens elements of the first outer lens plate close to the collimating optics have a larger radius, and the lens elements of the central lens plate have a comparatively smaller radius.

SPECIFIC DESCRIPTION OF THE INVENTION

(37) Embodiments of the invention are described, by way of examples, in the following description of the figures, with reference to the drawings. In this case, for the sake of clarity, also where different embodiments are concerned, identical or comparable parts or elements or regions are demoted by the same reference signs, sometimes lower-case letters being added.

(38) Within the context of the invention, features that are described only in relation to one embodiment can also be provided in all other embodiments of the invention. Amended embodiments of this kind are also covered by the invention, even if they are not shown in the drawings.

(39) All the disclosed features are per se essential to the invention. The disclosure both of the associated priority documents (copy of the prior application) and of the cited documents and the described devices of the prior art are hereby incorporated, in their entirety, in the disclosure of the application, also for the purpose of incorporating individual features or a plurality of features of said documents in one claim or in a plurality of claims of the present application.

(40) An embodiment of the light fixture according to the invention will first be explained with reference to FIGS. 1a and 1b:

(41) Said figures are merely highly schematic views of a light fixture 10 that comprises a housing 11. Inside the housing 11 (shown merely broken and by way of indication), an LED 12 is arranged on a circuit board 13 (indicated schematically). The LED is supplied with the required operating voltage via voltage supply lines (not shown here, but denoted for example 14 in FIG. 10). For the sake of simplicity, further electronic components that are provided for generating the operating voltage required for the LED are not shown.

(42) The LED emits light in a manner distributed over a large solid angular range of for example 180°. The LED 12 is located in a cavity 57 of collimating optics 15 that provides collimating optics. The collimating optics 57 comprises total internal reflection surfaces 58 and a cover portion 59. Overall the collimating optics 15, together with the LED 12, constitutes a light drive that is used for generating a substantially parallel light beam 27.

(43) Furthermore, a first outer lens plate 18, a central lens plate 19 and a second outer lens plate 74 are arranged inside the light fixture housing 11. The parallel bundle of light rays 27 strikes the light entry surface 28 of the first outer lens plate 18 as a parallel partial bundle of light rays 60, passes through said surface, and emerges in the region of the light exit surface 29 of the first outer lens plate 18. From there, the light strikes the light entry surface 30 of the central lens plate 19 and emerges through the light exit surface 31 of the central lens plate 19.

(44) From the central lens plate 19, the light strikes the entry side of a third lens plate, specifically the second outer lens plate 74, and emerges through the light exit surface thereof.

(45) In the embodiments of the light fixture according to the invention that are shown in the drawings, no further optical element is arranged in the light path behind the second outer lens plate 74. From there, the light can directly strike the building surface 17 to be illuminated, which surface is indicated only schematically and not to scale in FIG. 1a.

(46) Thus, in this embodiment, no termination glass or the like is provided in the region of the light exit opening 16 of the light fixture 10. In this case, the second outer lens plate 74 can function as a type of termination glass of the light fixture 16.

(47) The spacing between the first outer lens plate 18 and the central lens plate 19 is denoted 32 in the figures. In this case for example the spacing between the light entry surface 29 of the first outer lens plate 18 and the light entry surface 30 of the central lens plate 19 is measured. Other reference points are also covered by the invention.

(48) The spacing between the central lens plate 19 and the second outer lens plate 74 is denoted 75 in the figures.

(49) According to the invention, the spacing 32 between the two lens plates 18, 19 can be changed by means of a first adjustment device 20a.

(50) Furthermore, according to the invention, the spacing 75 between the central lens plate 19 and the second outer lens plate 74 can be changed by means of a second adjustment device 20b.

(51) The two adjustment devices 20a, 20b can comprise one motorized drive 21 each or a common motorized drive, which is merely indicated in FIG. 1a. The motorized drive 21 can for example receive control commands from a light fixture controller via a signal or control line (not shown).

(52) However, the adjustment devices 20a, 20b can also each comprise a manually operable actuation element, and a motorized drive can be omitted entirely.

(53) A manually actuatable element of this kind for changing the spacing is disclosed for example in FIGS. 10 and 13 of the German patent application DE 10 2017 122 956 A1 by the applicant, and therefore, in order to avoid repetitions, reference is made to the descriptions therein. In order to be able to vary the spacings 32, 75 in a mutually independent manner, it is also possible for two manually actuatable elements of this kind, adapted accordingly, to be provided for the two adjustment devices 20a, 20b.

(54) According to the invention, the design of the adjustment device is not important. The essential aspect of the invention is that the three lens plates 18, 19, 74 should be able to be displaced relative to one another in the axial direction Y, while changing their mutual spacings 32, 75.

(55) As is clear from the embodiment of FIG. 1a in connection with FIG. 4, a plurality of lens elements that are extended in direction X, referred to as lenticular lenses, in the form of extended lens elements 22a, 22b, 22c are arranged along the light entry surface 28 of the first outer lens plate 18. The lens elements 22a, 22b, 22c in the form of extended lens elements are arranged so as to be directly adjacent to one another. The invention also relates to the case in which small spacings are provided between the lens elements 22a, 22b, 22c.

(56) A plurality of lens elements 23a, 23b, 23c is also arranged on the central lens plate 19. The central lens plate 19 can comprise individual facets 23a, 23b, 23c that each have a spherical cross section and are consequently formed for example by a spherically curved body, e.g. a spherical section, or approximate a body of this kind.

(57) The facets can also be formed by a body having a different curvature, e.g. an aspherical curvature. In particular, the individual facets can each have a parabolic cross section, and consequently be formed as a rotational paraboloid.

(58) FIGS. 2 and 3 show a corresponding arrangement of said facets 23a, 23b, etc.

(59) As is clear from the drawing in FIG. 1a, each of the lenticular lens elements 22a, 22b, 22c is assigned a focal length 25. This results in an incident beam 60 of parallel light, which for example according to FIG. 1a strikes the lenticular lens element 22b, is focused in a focal point line 61 that extends perpendicularly to the paper plane of FIG. 1a. The individual light rays intersect here.

(60) Further along the path of the light, the light diverges from the focal point line 61 and strikes the lens element 23b on the central lens plate 19. Since the facet 23b—in the paper plane of FIG. 1a—is curved toward the lens 22b of the first outer lens plate 18 in an identical manner, said facet should be assigned an identical focal length 26. The focal length 25 of the lens 22b of the first outer lens plate 18 and the focal length 26 of the facet 23b of the central lens plate 19 are therefore identical.

(61) FIG. 1a shows the two lens plates 18, 19 spaced apart at a spacing 32 that is twice or approximately twice the focal length 25 (i.e. at the same time also twice the focal length 26).

(62) In this respect, the partial bundle of light rays 63 emanating from the focal point line 61 and striking the facet 23b is collimated again by the facet 23b and transformed into a parallel bundle of light ray 64.

(63) Said parallel bundle of light rays 64 then strikes the third lens plate 74, i.e. the second outer lens plate 74, and, at least in the perspective of the paper plane in FIG. 1a, is not influenced with respect to the optical path thereof.

(64) It should be noted in addition that the block diagram-like schematic view in FIG. 1a indicates a linear guide 62. According thereto, the first outer lens plate 18 is arranged so as to be movable relative to the housing 11, and the central lens plate 19 is arranged so as to be fixed relative to the housing 11. The first outer lens plate 18 can be displaced along the linear guide 26, in the axial direction Y, by means of the adjustment device 20a.

(65) Similarly, the second outer lens plate 74 can also be displaced in the axial direction Y, relative to the fixedly retained central lens plate 19, by means of the second adjustment device 20b.

(66) It is clear from FIGS. 2 and 3 that a plurality of lens elements 23a, 23b, 23c is arranged on the central lens plate 19, wherein only some of said facets are provided with reference signs.

(67) In combination with FIG. 1a, it is clear that, in this embodiment, the lens elements 22a, 22b, 22c, 23a, 23b, 23c on the first outer lens plate 18 and on the central lens plate 19 are arranged on the light entry side 28, 30 in each case, and the light exit surface 29, 31 of the relevant lens plate 18, 19 is kept planar.

(68) In other embodiments, the relevant lens plates 18,19 can also be oriented differently, for example such that the lens elements are arranged on the light exit side 29, 31 and the respective light entry side 28, 30 is kept free of lens elements. According to the invention, the orientation of the lens elements 22a, 22b, 22c, 23a, 23b, 23c with respect to the light source 12 is not important.

(69) It is clear from FIGS. 2 and 3 that the light fixture 10 can comprise a substantially circular light exit opening 16, and accordingly the three lens plates 18, 19, 74 are also circular disc-shaped. However, the invention is not limited to this geometry. Light fixtures that comprise a square or rectangular light exit opening or a light exit opening having another e.g. polygonal curved path, are also covered by the invention.

(70) It is furthermore clear from FIGS. 2 and 3 that, in the embodiment of FIG. 1a to 3, each light fixture comprises three collimating optics 15a, 15b, 15c. However, the number of collimating optics 15, 15a, 15b, 15c is arbitrary. It in particular also depends on the number and the design of the LEDs.

(71) Furthermore, it is clear from FIGS. 2 and 3 that each collimating optics 15 (and thus also each LED 12) is associated with a plurality of individual lens elements 23a, 23b, 23c. Thus, for example, the view in FIG. 2 shows that the collimating optics 15c is associated with more than twenty individual facets 23a, 23b, 23c.

(72) Since each collimating optics 15 or each LED 12 is in each case associated with a plurality of lens elements 23a, 23b, 23c, the structure of the light source 12 can be dissolved, and can no longer be identified by a viewer located in the space. Similarly, the structures of the LED or of the collimating optics are no longer identifiable in the light distribution on the building wall 17. The light distribution on the building wall is homogenous.

(73) According to an advantageous embodiment of the invention, the first outer lens plate 18 and the second outer lens plate 74 are each designed so as to be identical, but are arranged so as to be rotated by 90° relative to one another.

(74) These different rotational positions are clear from a comparison of FIGS. 1a and 1b, and FIGS. 4 and 6.

(75) The respective lenticular lenses 22a, 22b, 22c and 76a, 76b, 76 extend in mutually perpendicular directions X and Y.

(76) As shown in FIG. 1a, the two lens plates 18, 19 are positioned so as to be axially spaced from one another, such that each lenticular lens element 22a, 22b, 22c of the first outer lens plate 18 is fixedly associated with a plurality of specific lens elements 23a, 23b, 23c of the central lens plate 19. It is thus clear from FIG. 1a that the lens element 22b of the first outer lens plate 18 is always fixedly associated with the lens element 23b of the central lens plate 19. This fixed association is advantageously also maintained while and/or after a change in spacing between the two lens plates 18, 19 is being/has been performed.

(77) In addition, each lens element 23a, 23b, 23c of the central lens plate 19 is always fixedly associated with a lens element 76a, 76b, 76c of the second outer lens plate 74.

(78) As is clear from FIGS. 8a, 8b to 10a, 10b, in an embodiment of the invention, the adjustment device 20a can bring about a change in the spacing 32 between the first outer lens plate 18 and the central lens plate 19 from a spacing according to FIG. 10a, 10b that corresponds to a minimum spacing, and wherein the entry side 30 of the central lens plate 19 and the exit side 29 of the first outer lens plate 18 are almost in contact or can almost come into contact, to a second, maximum spacing 32 according to FIG. 8a, 8b, wherein the two lens plates 18, 19 are spaced apart by approximately twice the focal length 25, 26. In this case, the lengthening can be achieved for example continuously, in particular steplessly, by the adjustment device 20a.

(79) The light distribution generated on the building surface 17, in accordance with the different pacing positions of the two lens plates 18, 19 according to FIGS. 8a, 8b, 9a, 9b and 10a, 10b will be explained with reference to FIGS. 8c, 9c and 10c:

(80) In the case of a spacing position according to FIGS. 8a and 8b, in which the spacing between the two lens plates 18, 19 corresponds to approximately twice the focal length 25, 26, the beam angle 27 is minimal. As can be seen from the schematic view of FIG. 8a, said angle is 0°, since the light is parallel. In fact, in view of the large actual spacing (not shown to scale in FIG. 1a) between the building surface 17 and the light fixture 10, the beam angle 37 is for example approximately 12 to 16°. Said beam angle already corresponds to the beam angle of the light emitted by the collimating optics 15.

(81) If, using the adjustment device 20a, the two lens plates 18, 19 are moved toward one another, reducing the spacing 32, and for example an intermediate spacing according to FIG. 9a, 9b having a spacing 32 is reached, the central lens plate 19 can no longer maximally focus the light received from the first outer lens plate 18. FIG. 9a, 9b show that the lens element 23b can now focus the bundle of light rays received from the lens element 22b only to a lesser extent, and accordingly a second beam angle 38 is provided. Said second beam angle 38 is larger than the first beam angle 37.

(82) While FIG. 8c shows the light distribution that approximates a spot distribution, it is clear from FIG. 9c, in accordance with the spacing position of the lens plates 18, 19 according to FIG. 9a, that the light cone is widened. The width 51b of the light distribution according to FIG. 9c is larger than the width 51 of the light distribution according to FIG. 8c.

(83) However, the height 52 of the light distribution is unchanged.

(84) Whereas, proceeding from a spacing position according to FIG. 9a, 9b, the two lens plates 18, 19 are moved closer toward one another, and contact or approximately a contact position according to FIG. 10, 10b is achieved, no or virtually no collimating of the light received from the first lens plate 18 takes place by means of the central lens plate 19. In this case, the beam angle 39 is significantly larger than the beam angle 38 in the spacing position according to FIG. 8a, 8b, 9a, 9b.

(85) The light distribution on the wall 17 according to FIG. 10c accordingly has an even larger width 51c, compared with the light distribution curve 17 according to FIG. 8c.

(86) A maximum oval light distribution is achieved in this case.

(87) In this respect, changing the spacing between the lens plates 18, 19, and the fixed association of the lens elements 22a, 22b, 22c of the first lens plate 18 with the lens elements 23a 23b, 23c of the second lens plate 19 can result in a change in the emission characteristics of the light fixture 10, in particular a change in the beam angle 37, 38, 39 or a change in the ovality or the ovacity of the light distribution 34.

(88) During the spacing change, the rotational peripheral position of the central lens plate 19 relative to the first lens plate 18 is maintained even during the adjustment process, by means of a positioning device (not shown). This ensures that the fixed association of one specific lens element 22a, 22b, 22c, in each case, on the first outer lens plate 18 with a plurality of specific lens elements 23a, 23b, 23c, in each case, on the central lens plate 19, is maintained for different spacings 32.

(89) It is clear from FIGS. 4 and 5 that, in this embodiment, the first outer lens plate 18 comprises lenticular lenses in each case. These are cylindrical lenses that have spherical or aspherical curvatures along a first sectional plane (cf. FIG. 5), and those along a second sectional plane perpendicular to the first sectional plane are not curved. In this respect, the lenticular lenses 22a, 22b, 22c are symmetrical, and are oriented so as to be mutually parallel.

(90) It is clear from the embodiment of FIGS. 6 and 7 the second outer lens plate 74 also comprises lenticular lenses that are denoted merely by way of example, by reference sign 76a, 76b, 76c.

(91) The lenticular lenses of the second outer lens plate 74 are arranged in a direction W that is perpendicular to the direction X, in which the lenticular lens elements 22a, 22b, 22c of the first outer lens plate 18 according to FIGS. 4 and 5 are arranged.

(92) FIGS. 8a to 10c have already been described above.

(93) In the following, it will be explained, with reference to FIG. 11a to 13c, that the spacing 75 between the second outer lens plate 74 and the central lens plate 19 can be changed by means of a second adjustment device 20b, while maintaining the maximum spacing 32 between the first outer lens plate 18 and the central lens plate 74.

(94) FIG. 11a to 13c show three different spacing positions of central lens plates 19 and second outer lens plates 74, as well as the light distribution generated on building surface 17 in each case.

(95) It can be seen that, as the spacing decreases, proceeding from the position of FIG. 11a, 11b, to the spacing position of the lens plates 19, 74 according to FIGS. 12a and 12b and further with respect to a contacting position of the lens plates 19 and 74 according to FIGS. 13a and 13b, the light distribution becomes increasingly elongate or oval. In this case, the height 52, 52b, 52c of the light distribution changes, wherein the width 51 of the light distribution 34 does not change.

(96) It can be seen, with reference to the light distributions 34 of FIG. 11a to 13c, that the light fixture generates an oval light distribution in each case, at different spacing positions of the two lens plates 19, 74. An oval light distribution or illumination intensity distribution on the wall 17 is understood, in a manner conventional for a person skilled in the art, to be a light distribution that has a contour 53 that deviates from a circular shape of a light distribution, as shown according to FIG. 8c for example.

(97) For example, FIG. 12c shows an oval light distribution 34 having a correspondingly ova contour 53a, and a light distribution (shown in a simplified manner) that has a width 51 of the light distribution and a height 52b of the light distribution. The light distribution is therefore oval, or approximately elliptical. The exact contour 53a of the light distribution 34 of course depends on the lens element radii of curvature that are used.

(98) As the spacing between the two lens plates 19, 74 decreases, the light distribution 34 on the building surface 17 to be illuminated becomes higher, at a constant width. FIG. 13c shows the light distribution 53b on the building surface 17 to be illuminated, which light distribution corresponds to the spacing position of the two lens plates 19, 74 according to FIGS. 13a and 13b. It can be seen that the height 52c of said light distribution is significantly greater than the height 53 of the light distribution 34 of FIG. 11c. This effect results from the lens elements (denoted, by way of example, 76a, 76b, 76c) of the second lens plate 74 in each case no longer being able to collimate the partial bundle of rays, received from the lens elements 23a, 23b, 23c of the central lens plate 19, as effectively or as completely as in the case of the spacing position shown in FIGS. 11a and 11b.

(99) The decisive factor is that the height 52 of the light distribution 34 is changed by changing the spacing 75 between the lens plates 19 and 74, and thus the beam angle 38b, 39b in the sectional plane of FIG. 11b and 12b is thereby increased.

(100) In a sectional plane, perpendicular thereto, of FIG. 11a and 12a, the beam angle is not influenced. This is the reason why the width 51 of the light distribution 34 virtually does not change, and only the height 52, 52b, 52c varies.

(101) The following will now be explained with reference to FIGS. 14a to 16c:

(102) In this case, the spacing 32 of the first outer lens plate 18 from the central lens plate 19, and the relative spacing 75 between the second end plate 74 and the central lens plate 19 can be changed simultaneously.

(103) FIGS. 14a and 14b show a maximum spacing position, FIGS. 16a and 16b show a contact position, and FIGS. 15a and 15b show an intermediate position.

(104) The light distribution 34 according to FIGS. 14c, 15c and 16c corresponds to the spacing positions of the lens plates.

(105) It can be seen that a spot distribution according to FIG. 14c that, in the two sectional planes of FIGS. 14a and 14b, strikes the building surface 17 as a maximally narrow light beam, widens to a light distribution contour according to FIG. 15a and FIG. 16c, in the direction of the height 52 and in the direction of the width 51.

(106) In this respect, a light fixture according to FIGS. 1a and 1b can achieve oval light distributions, the ovality of which, i.e. the degree of ovality of which, can be adjusted. In this case, the width of the oval light distribution or the height of the oval light distribution can be adjustable in different axial directions. As is clear from the light distribution 34 according to FIGS. 14c, 15c and 16c, the light fixture can simultaneously also generate a light distribution that deviates from the oval light distribution, e.g. in the manner of a circle or a rounded square.

(107) The invention of course also covers embodiments of light fixtures that can generate light field contours other than those shown.

(108) A further embodiment of a light fixture 10 according to the invention will now be explained with reference to FIGS. 17 to 20:

(109) FIG. 17 shows a further embodiment, in a view according to FIG. 4, of a first outer lens plate 18 that now comprises what are known as lenticular facets 54a, 54b, 54c. These are facets that can for example have a more complex curvature.

(110) It is clear from FIGS. 17 to 20 that facets 54a, 54b, 54c can be arranged along a specified grid. In this case, it is possible in particular for the arrangement of said facets 54a, 54b, 54c according to the drawing in FIG. 17 to be along a grid that comprises rows and columns. In this case, the number of columns can be such as to correspond to the number of lenticular lenses of a lens plate 18 according to FIG. 4.

(111) In this case, each column of said facet arrangement can be divided into a plurality of individual facets.

(112) Said lenticular facets can have a particularly curved surface having different radii of curvature.

(113) FIG. 18 is an enlarged detail view of a single lenticular facet 54 from the lens plate 18 according to FIG. 17. It is clear from the two cross sections of FIGS. 19 and 20 that different radii of curvature can be provided along different, mutually perpendicular sectional planes. In this case it is assumed, for the sake of simplicity, that all the facets 54a, 54b, 54c of the lens plate 18 are designed identically.

(114) It should furthermore be noted that the facets according to the cross sections of FIGS. 19 and 20 have radii of curvature, wherein it is clear to a person skilled in the art that other curved surfaces, such as elliptical or parabolic curvatures, can be used.

(115) The invention further relates to the case where entirely different facets are arranged on one lens plate or on a plurality of lens plates, e.g. using freeform surfaces calculated from simulations.

(116) In the embodiments of the invention, a lens plate comprising lenticular lens facets, as shown in FIG. 17, can also be provided as a central lens plate 19 or as a second outer lens plate 74.

(117) In the embodiments of the invention, the spacing of the three lens plates 18, 19, 74 relative to one another can be changed by means of an axial movement, wherein the lens plates are oriented so as to be mutually parallel in any spacing position. The invention also relates to the case where, instead of a change in spacing of this kind among the lens plates 18, 19, 74, a displacement movement is performed by means of the adjustment device 20a, 20b such that, in addition to an axially directed, parallel displacement movement, or alternatively to a movement of this kind, a mutual spacing change among the lens plates 18, 19, 74 is achieved in that one of the lens plates 18, 19, 74 is rotated, tilted or inclined, or subjected to another, possibly more complicated, movement, with respect to another lens plate 19, 18, 74 in each case. It is possible to ensure here, too, that an association between at least one lens element, in each case, of a lens plate, and at least one other lens element of another lens plate is fixedly maintained.

(118) The invention also relates to embodiments in which said association is eliminated during a spacing change, and for different lens elements of a first lens plate, in each case, to be associated with different lens elements of a second lens plate, for example in discrete, different spacing positions.

(119) Ultimately, the drawings exclusively show embodiments in which the rotational position of the central lens plate 19 relative to the first outer lens plate 18 and the second outer lens plate is maintained during a spacing change. However, the invention also relates to embodiments in which a spacing change between the lens plates 18, 19, 74 results in a change in the rotational position of the central lens plate 19 relative to the two outer lens plates 18, 74.

(120) The method for changing the emission characteristics of a light fixture can be performed as follows:

(121) It is assumed that, in a museum, an art installation of a specified format is illuminated for the duration of a temporary exhibition. After said exhibition has ended, a new art installation having a different format is intended to be illuminated by the same light fixture on the same or another building surface. In order to adjust the light distribution of the light fixture to said format change of the art installation, the spacing of the three lens plates 18, 19, 74 relative to one another can be changed in the desired manner, by an operator, using the adjustment devices 20a, 20b.

(122) The change in the light distribution or the emission characteristics of the light fixture can be performed without elements of the light fixture needing to be exchanged or replaced, or even the light head of the light fixture needing to be exchanged or replaced.

(123) In the embodiments of the invention, an axial displacement of the first outer lens plate 18 and/or the second outer lens plate 74 relative to the central lens plate 19 takes place along an adjustment path that is approximately twice the focal length 25 of the lens elements 22a, 22b, 22c, 76a, 76b, 76c of the first outer lens plate 18 and the second outer lens plate 74. The invention also relates to embodiments in which the adjustment path that is provided by the adjustment device 20a, 20b for changing the spacing 32, 75 between the lens plates 18, 19, 74 is slightly or significantly greater or slightly or significantly smaller in comparison therewith.

(124) In the event of the lens elements 22a, 22b, 22c of the first lens plate 18 providing different focal lengths 25, the displacement path to be provided on the adjustment device 20a can be oriented to the focal length or twice the focal length 25 of one of the facets 22a, 22b, 22c.

(125) Advantageously, the displacement path to be provided by the adjustment device 20a, 20b is dimensioned such that a change in spacing between one pair of the lens plates 18, 19, 74 is provided, between a first optimized spacing in which a minimum beam angle, i.e. approximately parallel light, is generated, and a second spacing position, which generates a maximum beam angle, specified by the curvature of the lens elements.

(126) These two different spacing positions between the lens elements 18, 19 or 19, 74 that accordingly provide a maximum beam angle and a minimum beam angle can also be specified or predetermined by stops provided by the adjustment device 20a, 20b, and accordingly define a displacement movement of the first and second outer lens plate 18, 74 relative to the central lens plate 19.

(127) In the event of the change in spacing between the lens plates 18, 19, 74 being intended to be performed in discrete steps, in order to ensure specified spacing positions between the lens plates 18, 19, 74 (for example in order to allow for specified optimized, e.g. particularly homogeneous, light distributions), latching positions, i.e. positions in which the spacing positions between the lens plates 18, 19, 74 can be identified or determined by an operator or by an electronic or mechanical sensor or a control unit, can also be specified along the displacement path. As a result, it is possible to exclude the possibility, for example, of specific intermediate positions between specified latching positions not being reached.

(128) According to the embodiments of the invention, conventional LEDs 12, 12a, 12b, 12c and conventional collimating optics 15, 15a, 15b, 15c can be used. In this case, it is possible to use lens elements 23a, 23b, 23c that are aspherical but can be described approximately by a sphere, wherein the sphere can have diameters of curvature of between 1 and 50 mm for example.

(129) For example adjustment paths of between 2 and 40 mm, preferably adjustment paths in an order of magnitude of approximately 4 to 6 mm are provided as typical adjustment paths that are to be provided by the adjustment device 20 and along which a spacing change among the lens plates 18, 19, 74 can take place.

(130) In order to prevent disintegration of the structures of the LED 12 and the collimating optics 15, in order to generate an illumination intensity distribution or light distribution on the building surface 17 that is as homogenous as possible, approximately 10 to 50 lens elements 23a, 23b, 23c are provided on the central lens plate 19 per collimating optics 15, 15a, 15b, 15c and/or per LED 12, 12a, 12b, 12c and/or LED group, for example in the event of using a multichip LED. As a result, particularly optimized homogenization of the emitted light can be achieved.

(131) It is clear from the embodiments that the collimating optics 15 comprises a cavity 57, total internal reflection surfaces 58 and a cover region 59, i.e. a conventional lens centrally in the middle of the collimating optics 15. Differently designed suitable collimating optics that focus the light emitted by the corresponding light source are also covered by the invention.

(132) According to the invention, conventional lens plates 18, 19, 74 can be used for providing a light fixture 10 according to the invention, which lens plates have been used by the applicant for a considerable time e.g. as tertiary optics in light fixtures.

(133) In the embodiment of FIG. 21, reference is also briefly made to a further embodiment, the illustration of which in FIG. 21 corresponds to the illustration of FIG. 1a. In this case, collimating optics are provided that replace the collimating optics 66 of FIG. 1. In the embodiment of FIG. 21, a reflector 68 is provided as collimating optics 66, which reflector interacts with an assembly of a chip on board LED 67 that is arranged inside the reflector 68 or is associated with a reflector 68. The reflector 68, together with the chip on board LED 67, also emits a beam of light rays 27 of parallel or approximately parallel light.

(134) In the embodiment of FIG. 21, the three lens plates 18, 19, 74 can be arranged in the same manner as in the embodiment of FIG. 1. At different spacings 32, the light distribution of the light fixture 10 corresponds to the changed light distributions as can be seen in FIG. 8a-16c.

(135) According to a further embodiment of a light fixture 10 according to the invention according to FIG. 22, collimating optics 66 are provided that comprise collimating optics 15d comprising lens elements 70a, 70b, 70c in the manner of lenticular lenses arrange directly thereon. The lens elements 70a, 70b, 70c are thus arranged on the light exit side 56 of the collimating optics 15d that, unlike in the case of the embodiment of FIG. 1a, is not kept smooth but rather comprises the plurality of lens elements 70a, 70b, 70c.

(136) On the basis of a bundle of light rays 71 by way of example, it can be seen from FIG. 22 that the light emission behavior of said light fixture corresponds to that of the embodiment of FIG. 1a.

(137) The second lens plate 19b of the embodiment of FIG. 22 corresponds to the central lens plate 19 of the embodiment of FIG. 1a. It is irrelevant that in this case the lens elements 23a, 23b, 23c are arranged on the light exit side 31 of the lens plate 19b, and the lens entry side 30 is kept planar. In the embodiment of FIG. 22, the orientation of the central lens plate 29b could also be reversed.

(138) At different spacing positions of the lens plate 19b relative to the collimating optics 15d of the embodiment of FIG. 22, exactly the same changes in the emission characteristics of the light fixture result as are shown in FIGS. 8a to 16c on the basis of the embodiment of FIG. 1a.

(139) It is furthermore clear that the lens plate 19b can also cover a plurality of corresponding collimating optics 15d.

(140) The embodiment of FIG. 23 shows a further central lens plate 19. In this case the drawing in FIG. 23 corresponds to the drawing in FIG. 2.

(141) Instead of facet-like lens elements 23a, 23b, 23c according to the embodiments of FIGS. 2 to 3, in this case circular, concentric lenticular lens elements 69a, 69b, 69c are provided.

(142) In the embodiment, a central lens plate 19 is used, as is shown in FIG. 23. In this case, for example the same cross sectional view results as is indicated schematically, and not to scale, in FIG. 1a.

(143) If the central lens plate 19 according to FIG. 23 is arranged in different spacing positions relative to the two outer lens plates 19, 74, the identical light distributions result according to FIGS. 8a to 16c as in the embodiment of FIG. 1a.

(144) According to a further embodiment of the invention that is not shown, one or more of the three lens plates 18, 19, 19b, 74 are curved or bulged differently from that show in the various embodiments of the patent application.

(145) Alternatively, as shown in the drawings, the lens plates 18, 19, 74 can each be oriented along a plane.

(146) According to the embodiment of FIG. 24, the lens elements of a pair of adjacent lens plates can also be arranged so as to face away from one another, such that for example the lens elements 22a, 22b, 22c of the first outer lens plate 18 face the collimating optics 15, and the lens elements 23a, 23b, 23b of the central lens plate 19 are arranged on the side of the second lens plate 19 that faces away from the collimating optics 15.

(147) Finally, the embodiment of FIG. 26 is based on the basic structure of the embodiment of FIG. 24. In this case however, in contrast with the embodiment of FIG. 24, the lens elements 22a, 22b, 22c of the first outer lens plate 18 are provided with a first radius, such that the corresponding lens elements 22a, 22b, 22c can be assigned a first focal length 25.

(148) The lens elements 23a, 23b, 23c of the central lens plate 19 have a smaller radius in comparison, such that each lens element 23a, 23b, 23c of the central lens element 19 can be assigned a focal length 26 that is smaller than the focal length 25. This is a particularly advantageous embodiment.

(149) According to the invention, the group of features according to which the lens elements 22a, 22b, 22c of the first outer lens plate 18 all, or mostly, or at least on average, have a larger radius and/or a larger focal length than the lens elements 23a, 23b, 23c of the central lens plate 19 can be used advantageously in all the embodiments.

(150) The advantage of this particular geometry is inter alia that the bundle of light rays emitted by a specified lens element (e.g. 22b) of the first lens plate 18 is actually highly likely to also strike only specific accordingly opposing lens elements 23 of the central lens plate 19.

(151) It should be noted that the differences in the focal lengths or the differences in the average focal lengths between the lens elements 22a, 22b, 22c of the first outer lens plate 18 and the lens elements 76a, 76b of the second outer lens plate 74 and the lens elements 23a, 23b, 23c of the central lens plate 19 can be several millimeters. It is thus possible, for example, for the focal length of the lens elements 22a, 22b, 22c of the first outer lens plate 18 to be between 3 mm and 10 mm, and the focal length 26 of the lens elements 23a, 23b, 23c of the central lens plate 19 to be between 0.5 mm and 2.9 mm.

(152) The embodiments of FIGS. 3 and 25 are intended to also schematically explain that an individual lens element, e.g. the lens element 23e, can be formed not necessarily by a sphere, but rather also by a rotational paraboloid. However, the cap region 72 (FIG. 25) of each rotational paraboloidal lens element 23e can be described approximately by a circle 73. Said circle 73 can be assigned a radius R.

(153) The light beams entering into said cap region of a facet 23 (see FIG. 25) are focused, in the cap region, approximately to a common focal point 61.

(154) In fact, owing to the deviation of the cap shape 72 or the contour of the rotational paraboloid from a sphere, the situation can occur in which there is no exact focal point 61, but rather a focal point range. However, a focal point range of this kind can also be assigned an average focal length fm. This illustration takes into account the fact that an average focal length fm. can be calculated or determined upon considering all the beams passing through the cap region 72 or through the rotational paraboloid of said lens elements 23e.