Abstract
A luminaire for irradiating a target such as a printed product with printed-on lacquer or the like. The luminaire has a plurality of semiconductor light sources, wherein at least two first semiconductor light sources form a first light source line oriented in a lateral direction and wherein at least two further semiconductor light sources form a second light source line oriented in the lateral direction. The luminaire also has a plurality of separate lenses for collimating and/or collecting light from the semiconductor light sources, wherein each of the light source lines is assigned to one of the lenses.
Claims
1. A luminaire for irradiating a target such as a printed product with a printed-on lacquer or the like, comprising, a plurality of semiconductor light sources, wherein at least two first semiconductor light sources form a first light source line oriented in a lateral direction and wherein at least two further semiconductor light sources form a second light source line oriented in the lateral direction; and a plurality of separate lenses for collimating and/or collecting light from the semiconductor light sources, wherein each of the light source lines is assigned to one of the lenses.
2. The luminaire as claimed in claim 1, wherein at least one lens of the plurality of separate lenses extends over only one light source line in a transverse direction transverse to the lateral direction.
3. The luminaire as claimed in claim 1, wherein the lenses are manufactured as rod lenses and extend in the lateral direction substantially greater distance than in a transverse direction transverse to the lateral direction and/or than in a radiation direction transverse to both the lateral direction and the transverse direction.
4. The luminaire as claimed in claim 1, wherein at least one lens of the plurality of separate lenses has a constant lens cross section in the lateral direction and the lens cross section is circular, shaped like a partial circle, shaped like a Fresnel lens, or shaped as a convex or concave cylindrical lens.
5. The luminaire as claimed in claim 1, wherein at least one lens of the plurality of separate lenses comprises at least one flat section which extends along the lens in the lateral direction.
6. The luminaire as claimed in claim 1, wherein at least one lens is arranged in the radiation direction at a distance of no more than 10 mm and/or at least 0.1 mm from the at least two first semiconductor light sources.
7. The luminaire as claimed in claim 1, further comprising at least one multi-part lens holder which comprises at least one first web with at least two first holder openings and a second web with at least two second holder openings, said second web being spaced apart from the first web in the lateral direction, wherein a first lens of the plurality of separate lenses and a second lens of the plurality of separate lenses extend at least from respective first holder openings over a respective light source line to respective second holder openings in the lateral direction.
8. The luminaire as claimed in claim 1, further comprising at least one adjustment means for positioning a lens of the plurality of separate lenses relative to the at least two first semiconductor light sources, said adjustment means being in physical contact with the lens.
9. The luminaire as claimed in claim 1, further comprising at least one lateral holder which is in physical contact with a lens of the plurality of separate lenses in order to prevent relative movement of the lens relative to the semiconductor light sources in the lateral direction.
10. The luminaire as claimed in claim 16, wherein at least two of the lens holder, the lateral holder, and the adjustment means are formed as one piece.
11. The luminaire as claimed in claim 16, wherein the lens holder, the adjustment means, and/or the lateral holder are manufactured from a metal.
12. The luminaire as claimed in claim 16, wherein the lens, the lens holder, the adjustment means, and/or the lateral holder are polymer-free.
13. The luminaire as claimed in claim 7, further comprising a semiconductor substrate on which the semiconductor light sources are arranged, wherein the at least one lens holder is electrically insulated from the semiconductor substrate and the semiconductor light sources.
14. The luminaire as claimed in claim 13, wherein at least one printed circuit board forms the semiconductor substrate and the first lens extends completely over the at least one printed circuit board in the lateral direction.
15. A printing machine for producing printed products with a printed-on coating, such as lacquer, printed-on ink, or the like, comprising at least one luminaire as claimed in claim 1.
16. The luminaire as claimed in claim 1, further comprising a lens holder, an adjustment means for positioning a lens of the plurality of separate lenses relative to the at least two first semiconductor light sources, and a lateral holder which is in physical contact with the lens in order to prevent movement of the lens relative to the lens holder and/or the semiconductor light sources in the lateral direction.
17. The luminaire as claimed in claim 16, wherein the lateral holder and/or the adjustment means is detachably fastened to the lens holder.
18. The luminaire as claimed in claim 11, wherein the lens holder, the adjustment means, and/or the lateral holder are manufactured as a slab with a thickness of at least 1 mm.
19. The luminaire as claimed in claim 11, wherein the lens holder, the adjustment means, and/or the lateral holder are manufactured as a sheet with a thickness of no more than 1 mm.
20. A luminaire for irradiating a target such as a printed product with a printed-on lacquer or the like, comprising: a plurality of semiconductor light sources, wherein at least two first semiconductor light sources form a first light source line oriented in a lateral direction and wherein at least two further semiconductor light sources form a second light source line oriented in the lateral direction; a plurality of separate lenses for collimating and/or collecting light from the semiconductor light sources, wherein each of the light source lines is assigned to one of the lenses; at least one multi-part lens holder which comprises at least one first web with at least two first holder openings and a second web with at least two second holder openings, the second web being spaced apart from the first web in the lateral direction, wherein a first lens of the plurality of separate lenses and a second lens of the plurality of separate lenses extend at least from respective first holder openings over a respective light source line to respective second holder openings in the lateral direction; at least one adjustment means for positioning a lens of the plurality of separate lenses relative to the at least two first semiconductor light sources, the adjustment means being in physical contact with the lens; and at least one lateral holder which is in physical contact with a lens of the plurality of separate lenses in order to prevent relative movement of the lens relative to the semiconductor light sources in the lateral direction.
Description
BRIEF DESCRIPTION OF THE DRAWING
[0042] Particular embodiments and aspects of the invention are described below with reference to the accompanying figures, in which:
[0043] FIG. 1 shows an exploded view of a first embodiment of a luminaire according to the invention;
[0044] FIG. 2 shows the luminaire as per FIG. 1 in a perspective view;
[0045] FIG. 3 shows a second embodiment of a luminaire according to the invention in a perspective view;
[0046] FIG. 4 shows a cross-sectional view of the luminaire as per FIG. 3;
[0047] FIG. 5 shows a perspective view of a lens holder of the luminaire as per FIG. 3;
[0048] FIGS. 6a, 6b, and 6c show different views of a rod lens with a constant semi-circular cross section for a luminaire according to the invention;
[0049] FIG. 7 shows a longitudinal sectional view through a schematic illustration of a luminaire according to the invention as per a further embodiment;
[0050] FIG. 8 shows a longitudinal sectional view through a schematic illustration of a luminaire according to the invention as per another embodiment;
[0051] FIGS. 9a and 9b depict luminaires according to the prior art;
[0052] FIG. 10 shows a diagram of the distribution of the radiation intensity in the transverse direction for conventional luminaires and luminaires according to the invention;
[0053] FIG. 11 shows a diagram of the radiant flux within an irradiated surface depending on the distance of the irradiated surface from conventional luminaires and luminaires according to the invention;
[0054] FIG. 12 shows an apparatus for drying and/or curing a coating, comprising a plurality of luminaires according to the invention;
[0055] FIG. 13 shows a perspective view of a further embodiment of a luminaire according to the invention;
[0056] FIG. 14 shows the luminaire as per FIG. 13 in an exploded view; and
[0057] FIG. 15 shows a perspective view of a lens holder of the luminaire as per FIG. 13.
DETAILED DESCRIPTION OF THE DISCLOSURE
[0058] In the following description of specific embodiments using the figures, the same or similar components have been provided with the same or similar reference signs to aid readability.
[0059] A luminaire according to the invention for irradiating a target, such as a printed product with printed-on lacquer, is designated in general by reference sign 1.
[0060] The luminaire 1 illustrated in FIG. 1 comprises a plurality of semiconductor light sources 11, 12, 13, which are arranged in a grid-like fashion. First semiconductor light sources 11 are arranged along a first straight line, which defines a lateral direction L, and form a first light source line 21. A plurality of further (second) semiconductor light sources 12 are arranged along a second straight line, the second straight line arranged parallel to the first straight line, and form a second light source line 22. Further semiconductor light sources 13 are arranged along further straight lines, which lie parallel to the first straight line and the second straight line, and form further light source lines 23.
[0061] In anticipation of FIG. 12, it is mentioned that, in a specific embodiment, at least one luminaire 1 can be part of an apparatus 100 for irradiating a target 3. The target 3 can be movable relative to the luminaire or luminaires 1 along a conveying direction F. The luminaires 1 emit light, for example ultraviolet light and/or infrared light, in a radiation direction Z. The lateral direction L of the luminaires 1, corresponding to the orientation of the light source lines 21, 22, 23 and/or corresponding to the orientation of the individual lenses 31, 32, 33, corresponds to, in particular, an oblique direction Q of the target 3 transverse to, preferably perpendicular to, the conveying direction F and the radiation direction Z.
[0062] In the luminaire 1 as per FIG. 1, individual lenses 31, 32, 33 for collimating and/or collecting light of the semiconductor light sources 11, 12, 13 are assigned to the light source lines 21, 22, 23. In the embodiment illustrated in FIG. 1, an individual lens 31, 32, or 33 is individually assigned to each individual light source line 21, 22, or 23. It is clear that the assignment of a lens to a semiconductor light source is such that the entire light source line is covered by the respective lens. It is conceivable within the scope of the invention for a lens to be able to be assigned to a plurality of light source lines. By way of example, a width BL of a lens in the transverse direction can be dimensioned in such a way that the lens extends over a plurality of adjacent semiconductor light source lines. Independently of the width of the lens or the lenses, it is clear that the assignment of the light source line to its lens (which they can share with other semiconductor light source lines) is such that, in the lateral direction L, the entire light source line is covered by the lens in the radiation direction Z.
[0063] The light source line 21, 22, 23 can comprise at least 5, at least 10, at least 20, at least 30, or more semiconductor light sources. In the case of the luminaire illustrated in FIG. 1, a semiconductor substrate 70 with three printed circuit boards 71 arranged thereon is provided. The printed circuit board 71 is covered by a grid of semiconductor light sources 11, 12, 13. By way of example, the printed circuit board 71 can have at least two, at least three, at least five, or (as depicted here) at least seven light source lines 21, 22, 23. The printed circuit board 71 can have at least five, at least eight, at least ten (as depicted here), at least twelve, at least sixteen, or more light source transverse rows. In the case of the luminaire 1 depicted in FIG. 1, three printed circuit boards 71 are provided which are arranged next to one another in the lateral direction L, comprising semiconductor light sources 11, 12, 13 which are arranged flush in the lateral direction L and which form a semiconductor light source line that is assembled over the width of the luminaire 1 in the lateral direction L and that has at least 20 (30 are depicted) semiconductor light sources 11, 12, or 13 in each case. As shown in FIG. 2, a different rod lens 31, 32, 33 extends completely over each of these light source lines in the lateral direction.
[0064] The individual lenses 31, 32, and 33 (which may be rod lenses) illustrated in the case of the luminaire 1 as per FIGS. 1 and 2 each have the same shape. The cross section of the rod lenses 31, 32, and 33 is constantly semi-circular in the lateral direction L along the entire lens length LL. In particular, a high purity quartz glass, which is particularly transmissive (transmission of at least 99%) for ultraviolet light (or infrared light), can be used for the material of the lenses 31, 32, 33. Advantageously, such a quartz glass material can have particularly good mechanical and/or thermal stability. In this way, it is possible to attain particularly high powers, at which lenses made of a polymer material, such as a silicone material, would fail. A lens made of a silicone material can soften and/or overheat in the case of high UV radiant power densities. Compared to polymer materials, borosilicate glass exhibits higher thermal stability and stability against degradation as a result of the UV light.
[0065] The lenses 31, 32, and 33 are held in a slab-like frame 51, which embodies a lens holder. A protective window 6 (see FIGS. 7 and 8), for example made of glass, in particular made of a quartz glass or borosilicate glass, can be arranged on the side of the slab-like lens holder 51 that faces away from the semiconductor light sources 11, 12, 13 in the radiation direction Z. The lens holder 51 is delimited in the lateral direction L by a first web 52 on one side and by a second web 54 on the other side. The first web 52 and the second web 54 extend substantially parallel to one another in a transverse direction T at longitudinal sides of the lens holder 51 that are opposite one another in the lateral direction L. At their top and bottom ends in the transverse direction T, the webs 52 and 54 are rigidly interconnected by crossbars 60 of the lens holder 51 that extend in the lateral direction L. A non-conductive region 59 is provided between the lens holder 51 and the electronics of the printed circuit boards 70.
[0066] Holder openings 53, 55 corresponding to the number of lenses 31, 32, and 33 are respectively provided in the first web 52 and in the second web 54 of the lens holder 51. Each of the lenses 31, 32, and 33 extends in the lateral direction L from a first holder opening 53 in the first web 52 to a second holder opening 55 in the second web 54. The lenses 31, 32, and 33 are preferably dimensioned in such a way that they extend at least in sections into the opposing holder openings 53 and 55.
[0067] The lens holder 51 depicted in FIG. 1 is equipped on both sides with a holding and adjustment sheet 50. The adjustment sheets 50 serve in a functional union as lateral stops 57, 58 and as an adjustment mechanism 56 for orienting and securing the lenses 31, 32, and 33 relative to the lens holder 51. The holding and adjustment sheets 50 have a sheet section laterally on the outside, which acts as the lateral stop 57 or 58 by preventing a displacement of the lenses 31, 32, and 33, relative to the lens holder 51 in the lateral direction L, to the outside out of the holder opening 53 or 55.
[0068] The holding and adjustment sheets 50 comprise a second sheet section which acts as the adjustment mechanism 56 by contacting a flat side 35 of the lenses 31, 32, and 33, which faces the semiconductor light sources 11, 12, or 13 in the radiation direction Z, along a transverse line edge. The front transverse longitudinal edge of the holding and adjustment sheet 50 in the radiation direction Z easily determines the positioning of the lenses 31, 32, and 33 in the lens holder 51 relative to the semiconductor light sources 11, 12, and 13.
[0069] A pair of lateral ends 37 and 38 of the lenses 31, 32, and 33 extend into the drilled or milled holder openings 53 and 55 in the webs 52 and 54 of the lens holder 51. Preferably, neither lateral end 37 and 38, or only one of the two lateral ends 37 and 38, of the lenses 31, 32 and 33 is in physical contact with the first lateral stop 57 or the second lateral stop 58. To avoid damage from thermal stresses, it may be preferable to provide a sufficient tolerance in the lateral direction L between the lateral ends 37 and 38 of the lenses 31, 32 and 33 and the lateral stops 57 and 58. The lens holder 51 and the holding and adjustment sheets 50 are manufactured from metal, in particular the same metal material, for example stainless steel or aluminum.
[0070] In the case of the luminaire 1 as per FIGS. 1 and 2, a distance “a” of at least 0 mm, in particular at least 0.1 mm, and no more than 1 mm is provided between the lenses 31, 32, and 33, in particular the flat section 35 thereof, in the radiation direction Z. The back sides of the lenses 31, 32, and 33 in the radiation direction Z can be in physical contact with the LED light sources 11, 12, 13 provided it is ensured by construction that the slab-like lens holder 51 and the holding and adjustment sheets 50 are sufficiently far away from the conductive components of the semiconductor substrate 70 that a short-circuit can be reliably precluded.
[0071] The LED light sources are preferably UV and/or IR LED light sources. LED light sources can be contacted on the back side only and can have a flat light-emitting surface 10 (so-called flip-chip LEDs). Vertical chips, which are cheaper than flip-chip LEDs and which are contacted, firstly, on the back side and, secondly, on the light-emitting surface (front side) 10 by way of a bonding wire, can be used in the luminaire 1 according to the invention. If vertical chips with bonding wires are used, the distance between the light-emitting surface 10 of the LED vertical chips and the lenses is chosen to be sufficiently large to be able to provide sufficient space for the bonding wires and possibly an air gap between the bonding wires and possible electrically conductive material of a lens holder, of an adjustment mechanism, and/or of a lateral stop. It is conceivable to bring rod lenses 31, 32, 33 with a back-side flat section 35 into physical contact with the flat, light-emitting front side of flip-chip LEDs or the like such that the semiconductor light source itself can act as an adjustment mechanism.
[0072] FIGS. 3 and 4 illustrate a second embodiment of a luminaire 1 according to the invention. In relation to the luminaire 1 illustrated in FIGS. 1 and 2, the luminaire 1 illustrated in FIGS. 3 and 4 substantially differs by the different configuration of the lens holder 41, adjustment mechanism 46, and lateral holders 47 and 48, as depicted separately in FIG. 5. In the second embodiment of the luminaire 1 as per FIG. 3, the luminaire 1 comprises a semiconductor substrate 70 with only one printed circuit board 71 arranged thereon, with the printed circuit board 71 having a plurality of semiconductor light sources 11, 12, and 13 arranged thereon in lines 21, 22, and 23. In the embodiment as per FIG. 3, a single lens holder 41 is assigned to a single printed circuit board 71, said lens holder carrying a plurality of lenses 31, 32, and 33 in accordance with the number of light source lines 21, 22, and 23. The lenses 31, 32, and 33 extend over the entire width of the printed circuit board 71 in the lateral direction L. Each individual lens 31, 32, 33 covers the semiconductor light source 11 or 12 or 13 of the respective light source line 21 or 22 or 23.
[0073] The lens holder 41 comprises two webs 42 and 44 which are spaced apart from one another in the lateral direction L. A number of holder openings 43 and 45, corresponding to the number of lenses 31, 32, 33 that are held, are provided in each of the two webs 42 and 44 of the lens holder 41. The lenses 31, 32, 33 have the same cross-sectional shape as described for the luminaire 1 as per FIGS. 1 and 2. The lenses 31 and 32 and 33 have a flat side 35 facing the semiconductor light sources 11, 12, and 13 and a convexly curved front side 30 facing away from the semiconductor light sources 11, 12, and 13 in the radiation direction Z. The first holder openings 43 in the first web 42 and/or the second holder openings 45 in the second web 44 are dimensioned in a shape-complementary fashion in relation to the cross-sectional shape of the lenses 31, 32, 33. The holder openings 43 and 45 can be dimensioned in accordance with a loose fit or an oversize fit in relation to the cross-sectional dimension of the lenses 31, 32, 33 in the transverse direction T and/or the radiation direction Z such that a thermal expansion of the lens holder 41 does not result in stresses in the lenses 31, 32, 33. The shape-complementary dimensioning of the holder openings 43 and 45 causes the rearward inner side of the holder openings 43, 45 in the radiation direction Z to act as the adjustment mechanism 46 for positioning the lenses 31, 32, 33.
[0074] In the embodiment of the luminaire 1 as per FIGS. 3 to 5, the lens holder 41, adjustment mechanism 46, and lateral holders 47 and 48 are embodied in functional union by a lens-bearing sheet 40. The lens-bearing sheet 40 is delimited in the lateral direction L by bent sheet sections which form the lateral holders (or stops) 47 and 48 to prevent relative movement of the lens relative to the lens holder and/or the illuminants in the lateral direction L. By way of example, the lens-bearing sheet 40 can be shaped from a thin sheet with a thickness of no more than 0.5 mm, in particular of no more than 0.2 mm. By way of example, the lens-bearing sheet 40 can be shaped from a sheet by bending and punching and/or cutting, for example waterjet cutting or laser cutting. By way of example, the holder openings 43 and 45 can be cut or punched into the sheet. The webs 42 and 44 with the holder openings 43 and 45 formed therein can be formed by bending the sheet. The lateral holders or stops 47 and 48 can be formed by punching, cutting, or (as depicted here) multiple bending of the sheet. The lens-bearing sheet 40 can be fastened, for example adhesively bonded, plugged or screwed to the printed circuit board 71 and/or the semiconductor substrate 70 by way of one, two, or more non-conductive fastening components 49.
[0075] The webs 42 and 44 are respectively arranged between adjacent transverse row semiconductor light sources 11, 12, 13 in the lateral direction L, the pitch between adjacent semiconductor transverse rows being greater than the thickness of the lens-bearing sheet 40. A non-conductive region filled with air, another gas, or a vacuum is provided between the webs 42 and 44 of the lens-bearing sheet 40 and the semiconductor transverse rows. The lens-bearing sheet 40 is mounted via non-conductive components in a stationary fashion relative to the semiconductor substrate 70 and the semiconductor light sources 11, 12, 13 arranged thereon such that a short-circuit is reliably avoided.
[0076] In the embodiment as per FIGS. 3 and 4, the backward flat sides 35 of the lenses 31, 32, 33 are arranged in the radiation direction Z at a distance “a” of at least 0.1 mm, in particular at least 0.2 mm, and/or no more than 1 mm, in particular no more than 0.6 mm, preferably at a distance a of 0.4 mm, relative to the semiconductor light sources 11, 12, 13. The distance “a” is chosen to be as small as possible in order to efficiently focus the emitted light from the LED light sources 11, 12, 13 on the irradiated surface but chosen to be sufficiently large so as to reliably preclude a short-circuit of the semiconductor substrate 70 by the lens-bearing sheet 40.
[0077] FIGS. 6a, 6b, and 6c show different views of a lens 31, 32, 33, embodied as a rod lens, with a constant semi-cylindrical cross section. As characteristic parameters, the illustrated rod lens 31 has a lens length LL, a lens width BL, and a lens radius RL. In the depicted embodiment, the lens width BL corresponds to twice the lens radius RL. The lens width BL is greater than the width of a semiconductor light source, for example the UV LED 11. The UV LED 11 or other semiconductor light sources can, for example, have dimensions (length times width) of approximately 1×1 millimeter. In particular, the semiconductor light sources can have dimensions of 1,100×1,100±50 μm. A tolerance width between the lateral stops and the lenses of less than 2 mm, preferably 1 mm or less, can be provided in the lateral direction L. A lens whose surface at least partly corresponds to the surface of a cylinder is referred to as a cylindrical lens. The cylindrical lens can have a convex surface. The cylindrical lens can have a concave surface (not illustrated in any more detail). In principle, the lens length LL should measure at least 10-times the lens width BL, independently of whether the rod lens is formed with a semi-circular cross section (as depicted here) or any other cross section.
[0078] The length of the lenses LL is at least 20 mm, in particular 25.4 mm or more. The lens length LL can be at least 100 mm or at least 150 mm. It was found to be advantageous to choose the lens length LL to be less than 1,000 mm, in particular less than 300 mm.
[0079] FIG. 7 shows a schematic longitudinal sectional view of a luminaire 1 with the emphasis being on the orientation of the light source lines relative to one another, the orientation of the lenses relative to one another, and the orientation of the lenses relative to the semiconductor light sources. The type of holder for the lenses relative to the semiconductor light sources is not illustrated in FIG. 7; by way of example, embodiments as in FIGS. 1 and 2 or as in FIGS. 3 and 4 are conceivable. The same applies to FIG. 8. The differences between FIG. 7 and FIG. 8 will be discussed below.
[0080] The longitudinal section of the luminaire 1 as per FIG. 7 schematically illustrates a semiconductor substrate 70 with five light source lines 21, 22, and 23 arranged thereon. Similar rod lenses 31, 32, and 33 are arranged in front of the semiconductor light sources 11, 12, and 13 in the radiation direction Z, an individual rod lens in each case being assigned to a light source line and completely covering the light source line. The protective window 6 of the luminaire 1 is provided in front of the semiconductor light sources 11, 12, and 13 and in front of the rod lenses 31, 32, and 33 in the radiation direction Z. In particular, the protective window 6 is configured in such a way that it has no optical effect or virtually no optical effect on the beam path to the target 3 of the light emitted by the semiconductor light sources 11, 12, and 13. The target 3 can be an areal two-dimensional item, such as a paper web or surface, which can be provided with a coating that can be irradiated by the luminaire 1. Such a protective window 6 usually delimits a housing (not illustrated here) of a luminaire 1 in the radiation direction Z in order to protect the optics and/or electronics from contamination and/or damage. The working distance “z” extends between the target 3 and the luminaire 1 (more precisely, in this case, for example, the front surface of the protective window 6 in the radiation direction Z). It may be preferable to arrange the luminaire 1 and the target 3 in a plane parallel fashion with respect to one another at the working distance z. By way of example, a target 3 such as a printed paper web can be guided, at a working distance z in front of the luminaire 1 in the radiation direction Z, in a conveying direction F that corresponds to the transverse direction T of the luminaire 1 at a working distance z relative to the luminaire 1 (compare FIG. 12).
[0081] The distance b between the window front side 6 and the LED front side 10 can be 5.3 mm. In particular, the distance b between the outer side of the luminaire 1, in particular the protective window 6, is at least 4 mm, preferably at least 5 mm, and/or no more than 10 mm, preferably no more than 6 mm.
[0082] The lenses 31, 32, and 33 of the luminaire 1 are adapted and arranged to collimate and/or collect the light from the semiconductor light sources, in particular the UV LEDs and/or infrared LEDs, in particular in such a way that the light from the semiconductor light sources 11, 12, 13 is focused on a narrow focal line in the transverse direction T in the work plane defined by the target 3. In this way, it is possible to provide a particularly high peak radiant power density Imax of, e.g., at least 20 W/cm.sup.2 in the work plane, which may also be referred to as the target plane. In the arrangement of semiconductor light sources 11, 12, and 13 in individual light source lines 21, 22, or 23 and assigned lenses 31, 32, and 33, as depicted in FIG. 7, it is possible to determine centerlines for the semiconductor light sources 11, 12, and 13 and the lenses 31, 32, and 33. In the transverse direction T, the semiconductor light source lines are arranged at a constant, unchanging distance or line pitch AH from one another. In the transverse direction T, the lenses are arranged at a constant, unchanging distance or lens pitch AL next to one another. The centerlines of the lenses are arranged flush with the centerlines of the semiconductor light source lines.
[0083] The assembly distance “a” is formed in the radiation direction Z between the light-emitting front side 10 and the back side of the lenses 31, 32, and 33, where the back side is exemplarily formed as a flat side 35. The assembly distance “a” between the light-emitting front side 10 of the semiconductor light source 11, 12, and 13 and the back side of the optically effective lenses 31, 32, and 33 in the radiation direction Z is chosen to be as small as possible. The assembly distance “a” is discussed in more detail above in the context of the different embodiments as per FIGS. 1 and 2 or FIGS. 3 and 4.
[0084] As can easily be identified in FIG. 7 (and FIG. 8), the lens width BL in the transverse direction is greater than the width BH of the semiconductor light source 11, 12, 13 in the transverse direction. In the exemplary embodiment illustrated here, the lenses are dimensioned in such a way that the lens width BL is less than the pitch AZ to the light source lines (e.g., 21 and 23) immediately adjacent to the light source line (e.g., 22) covered by the lens. This neighboring line pitch AZ is at least equal to, preferably greater than, the center pitch AH of two immediately adjacent light source lines (e.g., 21, 22). In a different arrangement (not illustrated here), for example in the case of an arrangement with an even number of light source lines, it may be the case that the centerline m is arranged in a region between two light source lines that are adjacent to one another in the transverse direction T. By way of example, the protective glass 6 can be a 3 mm thick, high-purity quartz glass panel.
[0085] The curves denoted by reference sign “c” in the graphs of FIGS. 10 and 11 discussed below relate to a relative arrangement of lenses and semiconductor light sources as in the case of the luminaire 1 as per FIG. 7. The curves denoted by reference sign “b” in FIGS. 10 and 11 below relate to an arrangement of lenses and semiconductor light sources as in FIG. 8.
[0086] FIG. 8 shows a luminaire 1 which essentially differs from the arrangement as per FIG. 7 by way of a different relative position of the lenses 31, 32, and 33 relative to the light source lines 21, 22, and 23. By way of example, such an arrangement can be realized in luminaires which are embodied as in FIGS. 1 and 2, FIGS. 3 and 4, or FIGS. 13 and 14 (see below). The difference between the arrangements as per FIGS. 7 and 8 consists in the center pitch of the lenses AL in the embodiment as per FIG. 8 being greater than the center pitch of the light source lines AH.
[0087] In the exemplary embodiment as per FIG. 8, the number of light source lines is chosen to be odd and the central light source line 21 in the transverse direction T has a centerline m which is arranged flush with the centerline of the lens 31 which is assigned to and covers said light source line. The pitches of the semiconductor light source lines AH relative to one another are the same. The center pitches of the lenses AL in the transverse direction T are the same and constant.
[0088] Starting from the transverse center “m” of the semiconductor substrate 70 and going to the outside, there is an increasingly larger transverse offset V1, V2 between the centerlines of the semiconductor light source lines 22 and 23 and the lenses 32 and 33, respectively, assigned thereto. In the depicted embodiment, the offset V1 of the light source line closest to the transverse center “m” of the semiconductor substrate 70, the first transverse offset V1, corresponds to the difference between the lens pitch AL and the light source line pitch AH. The light source line 23 second closest to the transverse center of the semiconductor substrate 70 has an offset V2 in the transverse direction relative to the centerline of the lens 33 assigned thereto. In the example illustrated in FIG. 8, the offset V2 in the case of the second light source line is twice as large as the offset V1 in the case of the first, non-central line 22.
[0089] According to the invention, provision can be made, for example, for the center pitch AH of the light source lines 21, 22, and 23 to be non-constant in order to set the offset between different light source lines and the respectively assigned lenses; as an alternative or in addition thereto, the lens center pitch AL can be non-constant (vary) in order to specifically set the offset of light source lines and lenses. Other variations in the arrangement, dimensioning, etc., of semiconductor light sources, light source lines, and/or lenses relative to one another are possible in order to bring about an influence on the optical effect of the lens relative to the semiconductor light sources, for example different offsets.
[0090] FIGS. 9a and 9b schematically show different luminaires known from the prior art. In accordance with the embodiment of FIG. 9a, a plurality of parallel line UV LEDs which radiate on a target are arranged on a semiconductor substrate. A protective glass practically without refractive power is arranged between the UV LEDs and the target as part of a housing frame of the luminaire, which is not illustrated in more detail. The emitter illustrated in FIG. 9a differs from the prior art emitter illustrated in FIG. 9b in that the semiconductor light sources are individually coated with a silicone potting compound, which forms lenses for the individual UV LEDs. Each individual UV LED is covered by a partly spherical potting compound lens body. In the graphs in FIGS. 10 and 11 described below, the curves relating to luminaires according to the prior art are denoted by reference sign “a” for the embodiment as per FIG. 9a and reference sign “b” for luminaires as per FIG. 9b.
[0091] FIG. 10 illustrates graphically the profile of the radiation surface density I in W/cm.sup.2 in the transverse direction T relative to the center “m” of one of the semiconductor substrates 70 (in millimeters). The semiconductor substrate 70 has a total width of approximately 30 mm, i.e., 15 mm on each side of the centerline m in the transverse direction. In the longitudinal or lateral direction L, the semiconductor substrate 70 has a width of approximately 25 mm. The radiant power density illustrated in FIG. 10 relates to values at a working distance z of 20 mm from the front side of the protective glass 6 of the luminaire 1, which is spaced apart by the distance b=5.3 mm from the light-emitting surface 10 of the semiconductor light sources 11, 12, 13. The radiant flux of the semiconductor light source (1.6 W/LED), i.e., the power consumption of the semiconductor light sources, the number of semiconductor light sources (n=210), the arrangement of the semiconductor light sources, the number of semiconductor light sources in the longitudinal direction (m=30 per substrate), and the number of semiconductor light sources in the transverse direction (w=5) are constant. The profile of the radiant power density curves a, b, c, and d substantially corresponds to a Gaussian distribution about the centerline m in all four cases.
[0092] The widest scattering corresponding to the widest curve and the lowest peak intensity Imax of the curve at the working distance of 20 mm is exhibited by the luminaire as per FIG. 9a without an optical element between the semiconductor light source and target. The embodiment as per FIG. 9b has a slightly increased peak intensity in comparison with the embodiments without an optical unit as per FIG. 9a and exhibits a narrower width of the bell, corresponding to stronger focusing.
[0093] Surprisingly, curves c and d show significantly better results. It was expected that the optics-free luminaire would exhibit the highest power values due to the lack of absorption by the optical elements. Curves c and d of the luminaires according to the invention exhibit significantly higher peak powers. Curve c of an optical arrangement as per FIG. 7 without an offset between the lenses and the light source lines has a peak power of almost 12 W/cm.sup.2. Curve b for an optical arrangement as illustrated in FIG. 8 shows a peak power of approximately 13 W/cm.sup.2, which is almost twice the magnitude of the peak power of the conventional embodiment as per FIG. 9a without an optical element. The measurement values underlying the graph are listed in the following table.
TABLE-US-00001 TABLE 1 Power I as a function of the transverse distance from the substrate centerline m without half cylinder, optics half cylinder silicone offset (a) (c) (b) (d) T [mm] I [W/cm.sup.2] I [W/cm.sup.2] I [W/cm.sup.2] I [W/cm.sup.2] −40 1.1 0.1 0.1 0.1 −30 2 0.1 0.6 0.1 −25 2.9 0.2 1.5 0.1 −24 3.1 0.2 1.7 0.1 −23 3.3 0.4 1.9 0.1 −22 3.5 0.6 2.1 0.1 −21 3.7 0.9 2.3 0.1 −20 3.9 1.3 2.6 0.2 −19 4.1 1.8 2.9 0.4 −18 4.3 2.3 3.2 0.7 −17 4.5 2.9 3.5 1.1 −16 4.7 3.4 3.7 1.7 −15 4.9 4 4 2.5 −14 5.1 4.7 4.4 3.6 −13 5.4 5.4 4.7 4.8 −12 5.5 6.2 5.1 6 −11 5.7 7 5.3 7.1 −10 5.9 7.9 5.7 8.1 −9 6.1 8.5 6 9 −8 6.3 9.1 6.4 9.7 −7 6.4 9.6 6.6 10.5 −6 6.5 9.9 6.9 11.1 −5 6.6 10.4 7.2 11.6 −4 6.7 10.8 7.5 12.1 −3 6.8 11.1 7.8 12.3 −2 6.8 11.5 7.9 12.7 −1 6.9 11.7 8 13 0 6.9 11.8 7.7 13.1 1 6.9 11.9 7.7 13 2 6.8 11.7 7.6 12.9 3 6.8 11.5 7.4 12.5 4 6.7 11 7.4 12.1 5 6.6 10.6 7.3 11.6 6 6.5 10 7.1 11 7 6.4 9.4 6.9 10.5 8 6.2 8.7 6.5 9.7 9 6.1 8 6.2 8.8 10 5.9 7.4 5.7 8 11 5.7 6.7 5.4 7 12 5.5 6 5 5.9 13 5.3 5.2 4.6 4.7 14 5.1 4.4 4.4 3.5 15 4.9 3.8 4 2.5 16 4.7 3.1 3.8 1.7 17 4.5 2.7 3.5 1.2 18 4.3 2.2 3.1 0.7 19 4 1.8 2.9 0.5 20 3.8 1.4 2.7 0.3 21 3.6 0.9 2.4 0.2 22 3.4 0.6 2.2 0.2 23 3.2 0.4 1.9 0.1 24 3 0.3 1.7 0.2 25 2.8 0.2 1.4 0.2 30 2 0.1 0.6 0.2 40 1.1 0.1 0 0.1
[0094] In the transverse region ±10 mm about the centerline m, the luminaires 1 according to the invention have radiant power densities in the region above approximately 7 W/cm.sup.2 throughout. Thus, the luminaires 1 according to the invention enable a continuously and consistently significantly higher radiant power density in the region of ±10 mm about the centerline m than the peak power k1 of a conventional embodiment (a) and is continuously above the peak power k2 of a conventional luminaire with semiconductor potting compound optics (b).
[0095] The graph illustrated in FIG. 11 shows the peak radiant flux for the different luminaires as per FIGS. 7, 8, 9a, and 9b in W/cm.sup.2, as a function of the working distance z between the luminaire and the target plane. Measurement values for working distances z in the range between 5 mm and 90 mm are illustrated. For the working distance z equal to 20 mm, the maximum radiant power densities k1 and k2 of the conventional luminaires as per FIG. 9a or 9b are illustrated in a manner corresponding to FIG. 10.
[0096] The luminaires 1 according to the invention as per the arrangements illustrated in FIGS. 7 and 8 result in significantly higher peak intensities than conventional emitters for working distances between 5 mm and 50 mm. In the working distance range of 50 mm to 90 mm, the peak intensity for the radiation surface density for the arrangement as per FIG. 8 is better than in the case of conventional emitters. It was found that the radiant power density peak intensity for the luminaire 1 according to the invention at a working distance z of between 50 mm and 90 mm is at least as high as in the case of a conventional luminaire.
[0097] Apart from the variation of the working distance z, the parameters in the graph as per FIG. 11 are the same as in FIG. 10. The measurement values corresponding with the graph are reproduced below.
TABLE-US-00002 TABLE 2 Peak radiant power density or peak power Imax as a function of the working distance z for different luminaires without half cylinder, optics half cylinder silicone offset (a) (c) (b) (d) z [mm] Imax [W/cm{circumflex over ( )}2] 0 23 19 17 23 5 16 18 15 21.5 10 12 17 12 19 20 7 12 8 13 50 3 4 4 4.5 90 1 2 2 2
[0098] FIG. 12 schematically shows an apparatus 100 which comprises four luminaires 1 according to the invention for irradiating the target 3 that is guided in a conveying direction F corresponding to the transverse direction T in the work plane parallel to the luminaires 1.
[0099] FIGS. 13 and 14 illustrate a further embodiment of a luminaire 1 according to the invention. Compared to the luminaire 1 illustrated in FIGS. 1 and 2, or FIGS. 3 and 4, the luminaire 1 illustrated in FIGS. 13 and 14 essentially differs by the different configuration of the lens holder 81, the adjustment mechanism 86, and the lateral holder 87 (an identical opposing lateral holder is not depicted here). The lens holder 81 is depicted separately in FIG. 15.
[0100] The lens holder 81 comprises a first web 82 and a second web 84 as separate individual parts. Provided in each of the webs 82, 84 are a number of holding openings 83, 85 which corresponds to the number of lenses 31, 32, 33 (not depicted in FIG. 15; an outermost lens is not depicted in FIGS. 13 and 14). The holding openings 83, 85 are adapted and arranged to have a complementary shape to the lenses 31, 32, 33 and, as a result, form an adjustment mechanism 86 in accordance with the embodiment as per FIGS. 3 and 4 as described above.
[0101] The webs 82 and 84 are embodied in sheets 80 with bent assembly sections. Further stop sheets 80′ without holding openings serve as the lateral stop 87 (the opposite lateral stop is not depicted here). The assembly sections of the sheets 80, 80′ can be affixed to an assembly plate of the luminaire 1 by, for example, screws. The semiconductor substrate 70 can be provided on the assembly plate, with the electrically conductive components being separated from the assembly plate by a non-conductive ceramic layer as the non-conductive region 59, for example an AlN slab. The sheets 80 can be arranged between adjacent printed circuit boards 71 in the lateral direction L such that an air gap and/or a non-conductive ceramic slab section is provided in the lateral direction between the sheet 80 and electrically conductive components of the semiconductor substrate 70.
[0102] Although illustrated and described above with reference to certain specific embodiments and examples, the present disclosure is nevertheless not intended to be limited to the details shown. Rather, various modifications may be made in the details within the scope and range of equivalents of the claims and without departing from the spirit of the disclosure.
