DK145207B - LIGHTING LIGHT WITH A MIRRORING REFLECTOR - Google Patents

Description

in 145207

The invention relates to a lighting arrangement comprising a light source having a substantially axially symmetric, closed spatial restriction surface and a reflective reflector having a reflection surface, the edge or edges of which define a substantially flat light output aperture, the limiting surface of the light source having a parallel output aperture axis of symmetry and intersected by a normal plane for this axis of symmetry in a first sectional curve, while the reflection surface of the same normal plane is intersected in another 10 sectional curve with end points located at the light exit orifice and with a substantially first curve section lying behind the first sectional curve, first cut curve.

By a light source having a substantially axially symmetrically closed spatial restriction surface, here is understood both cylindrical light sources with e.g. circular or elliptical cross-section as light sources, the surface of which essentially forms a rotating surface, e.g. a ball surface or a rotary ellipsoid surface. Depending on the shape of the light source, there may be one or more axis of symmetry for the light source surface, however at least one axis of symmetry will be parallel to the plane of the light output aperture. Thus, for cylindrical light sources, there is only a single axis of symmetry, parallel to the plane of the light output, while at a light source surface which is not only axially symmetric but rotationally symmetric, there will be more than one axis of symmetry. for a ball surface will be a axis of symmetry corresponding to any diameter and for a rotary ellipsoid surface two symmetric axes, one of which is parallel to the plane of the light output aperture. For the above-mentioned normal plane, this means that such planes at cylindrical light sources and light sources with rotating ellipsoid surfaces, the longitudinal axis being parallel to the plane of the light output aperture 35, will always be parallel to each other, while at light sources with spherical surfaces and rotating ellipsoid surfaces, where The plane of the light output aperture may be both parallel normal planes to each one, with the plane of symmetry parallel parallel symmetry axis and normal planes in the form of symmetry planes intersecting each other in the axis of symmetry perpendicular to the plane of the light output aperture.

Light sources of the kind in question include both matte filament lamps of elongated or round shape and various matte vapor lamps, in particular with luminous coating, as well as lamps with clear flask, e.g. low pressure and high pressure sodium lamps. Such light sources are applicable in a variety of areas, in particular in the areas of office, workplace, road, space, sports and facade lighting.

Common to these applications is that the lighting fixture for a light source must have a high efficiency, ie. as small losses as possible and small dimensions, while being able to concentrate and distribute light on a defined area of the illuminated surface, ie. within a defined space angle range as seen from the reflector light outlet opening.

The requirement for a high efficiency is due to direct lighting operating economic considerations, while the desire for small dimensions is partly due to the manufacturing costs of the luminaire and partly to space, aesthetic and other considerations. The purpose of the light-directing effect is to provide high illumination in the places where it is needed, and at the same time limit the glare for normal viewing directions. Thus, for surface lighting, for example, on a floor plane, as high brightness levels as possible are desired at the boundaries of the illuminated area, ie. in directions near the opening directions of the luminaire to achieve uniform illumination simultaneously with a sharp reduction in brightness immediately outside the opening directions for the purpose of glare limitation.

35 Both for lighting theoretical and technological reasons, there is a contradiction between the three above-mentioned requirements for lighting fixtures, so that a high priority for one of the mentioned requirements will usually mean that the other requirements can only be met to a lesser extent. Thus, in luminaires having a small light output aperture for dimensional reasons, it is only possible to increase the luminous flux through an increase in the luminance of the light source by inter-reflection between light source and reflector, which, however, at the same time increases the losses.

The extent to which the above three requirements can be met depends on the lighting design of the lighting fixture, and for this reason, luminaires with reflective reflectors have gained more widespread in recent years, since such luminaires usually have a higher efficiency and better control over light emission than diffusers with diffusive reflectors.

15 In most such luminaires, the reflector has a parabola-like cross-section and encloses the space source light source quite closely. Hereby, however, part of the light emitted by the light source together with the heat generated will be reflected back on the light source, thereby reducing the efficiency partly due to absorption of the light and partly due to the heating of the light source, which is particularly applicable to fluorescent tubes.

However, in particular for cylindrical light sources, reflector designs are known in which loss of this kind is avoided by the fact that at least the upper portion of the reflector cross-section in a normal plane to the longitudinal axis is designed as deviations for the cut-off curve of the light source surface in the same plane. In this reflector design, which e.g. is known from the specification of British patent no.

30 884,068, reflection back on the light source is avoided. However, in this known reflector design, no indication is given as to how the other parts of the reflector cross-section around the light output aperture should be designed in order to meet the other two above-mentioned requirements regarding control of light emission and obtaining small reflector dimensions. Nor is there any indication of how a unwinding part of a reflector cross-section can be combined with other forms of cross-sectional curves, so that both dimensional and aesthetic requirements and requirements of production-friendliness can be met.

It is an object of the invention to provide an illumination luminaire of the kind in question which allows to meet all three of the above requirements to a great extent and thus, in relation to known loss-less luminaires, allows for smaller reflector dimensions and better control of the light emission.

For this purpose, the lighting fixture according to the invention is characterized in that the first curve section of the second section curve is limited by two half-keys to the first section curve, which half-keys extensions intersect on the side facing the light output opening of the first section curve at a mutual angle of less than 180 ° and also outside the angular space between aperture boundary jets from each intersection of said half-tangents with the second intersection curve to the opposite end point of the other intersection curve, or 20 coincides with each of said aperture boundary beams, and the second intersection curve between the first curve section and one of said end points has a second and a third curve section, for each of which the normal in any curve point is formed by the angle bisector line between the tangent from the curve point to the curve described by the said limiting half-keys for the first curve section and the intermediate portion of the the first s rivet curve, and a line through the curve point parallel to the aperture boundary beam to the end point which does not belong to that curve section.

In this reflector design, said second and third curve sections of the second section curve, which lie outside the first curve section of the two settlers, are thus directly determined taking into account the shape 35 of both the first section curve and said first curve section, said curve described by said limiting half-keys and the intermediate portion of the first section curve will constitute the illuminating opening profile of the light source plus the first curve section. Through the design shown, the second and third curve sections of the second section curve will have the greatest possible curvature, so that the overall reflector can be imparted to minimum dimensions 5 without reflecting light outside the directions determined by the opening boundary beams.

Likewise, the reflector, like the aforementioned known reflectors, will be loss-free in the sense that light and heat are not reflected back onto the light source. The 10 not entirely avoidable losses will mainly be due to the fact that a reflector with a reflection factor of one hundred percent cannot be produced. The efficiency of the reflector in a fixture according to the invention will typically be in the range of 80-90%.

Further, the luminaire will only emit light within the space angle range determined by the opening boundary beams, and viewed from directions within this area, the reflector will provide a maximum flared light aperture and thus an optimal relationship between the brightness and the area of the light aperture 20.

The invention is explained in more detail below with reference to the schematic drawing, in which fig. 1 is a schematic cross-sectional view of a first embodiment of a luminaire according to the invention to a circular cross-section light source; FIG. 2 is a cross-sectional view of another embodiment of the non-symmetric reflector luminaire and an elliptical cross-section light source; FIG. 3 by a and b luminaires with non-symmetric.

30 reflectors and light sources with elliptical and circular cross sections, respectively, where the first curve section consisting of devilers goes smoothly into the rest of the second section curve, ie. second and third, curve sections, fig. 4 by a-c luminaires with non-symmetrical reflectors, where the unwinding portions of the second cut curve start from the same point on the first cut curve; 5 at a-c corresponding fixtures, where the unwinding parts start from offset points 145207 6 on the first section curve; 6 by a-f various luminaires with symmetrical reflectors for light sources of circular cross section, and fig. 7 at a and b are different luminaires with symmetrical reflectors for light sources of elliptical cross section.

X fig. 1 is a cross-sectional view of a basic symmetrical embodiment of a luminaire according to the invention with a reflector having a symmetrical reflection surface and a light source of circular cross-section, i.e. either a circular 10 cylindrical light source in the form of e.g. a fluorescent lamp or a light source, the surface of which forms an orbital surface about a axis of symmetry parallel to the plane of the reflector's aperture orifice. A normal plane of the axis of symmetry thus defined intersects the limiting surface 15 of the light source in a first section curve 2 and the reflection surface in a second section curve 1.

As explained above, the luminaire according to the invention has a reflective reflector of the kind in which the second cut curve 1 consists in part of two unwinding 5 and 20 6 for the first cut curve 2. In accordance with the invention, the curve section of the second cut curve 1 confined to a region between two half-keys 3 to the first cut curve 2, whose extensions 3a past the first cut curve 2 towards the light output opening intersect at an angle of less than 180 ° and in the embodiment of FIG. 1, the opening border beam 4 also falls from the intersection points of each of the half-keys 3 with the second cut-off curve 1 to the opposite endpoint of the second cut-off curve 1, and the other, lying outside this first curve section 5, 6, i.e. second and third curve sections 7 and 8 of the second section curve 1 have such a course that the normal to curve 1 at any point B of each of these curve sections 7 and 8 between the first 35 curve section and one of the end points of the curve is formed by the angular half-line between the parallel point 3b of the opening boundary beam to the endpoint of the non-relevant curve section, through the respective curve point B and the tangent 3c from this point to the curve described by said half-keys 3 and the intermediate part of the first section curve 2.

In the embodiment of FIG. 1, the second section-5 curve 1 is symmetrical about the angular half-line between the two aperture boundary beams 4, so that, for the sake of clarity, the figures show only one of the extensions 3a of the half-keys 3 and the corresponding aperture boundary beam 4.

10 The shape of the second section curve 1, and thus the reflection surface itself, is explained in the following by means of the embodiment shown in FIG. 1, a coordinate system having zero in the plane of symmetry parallel to the light source surface of the light source surface and whose ordinate axis Y is formed by the angular bisector between the two opening directions. For the mathematical explanation of the section curve, the fixed angles α and (S, respectively, which are the opening angle, i.e. the half angle between the two opening boundary beams 4 and the angle from the abscissa axis X of the coordinate system are introduced to the starting point of the first section curve 2. To determine the coordinates X, Y for any curve point on one half of the symmetrical second section curve, a further variable parameter in the form of the angle Θ is taken from the 25 χ axis to the point of contact of the first section curve 2 for the tangent. from the relevant curve point on the cut curve 1 as well as the radius r of the circular first cut curve 2.

From this it will be seen that the section 5 of the half considered as such of the symmetrical second cut curve 1, consisting of a settler for the first anit curve 2, in this case a circle settler, starts at the value 0 = β. In the example shown, where the extension 3a of the semiconductor 3 defining the end of this section coincides with the opening boundary beam 4 to 145207 8 the end point of the opposite symmetrical half of the second section curve 17, it is further seen that the end of that section for the considered half of the second cut curve 1 will be determined by the value 5 0 = 1 + ',

Within this section of the considered half of the symmetrical second intersection curve 1, the coordinates to any point such as FIG. 1, determined by: 10 x = r (cos0 + (0-8) sinØ) (1) y = r (sinØ - (0- β) cosØ) (2)

Thus, the remaining section 7 of the considered half of the second cut curve 1 extends from the value 0 = π + α to the end point 15 located at the light output aperture, where the value 0 is seen to be equal to 2ir - cu. such as. point B, on this curve the coordinates are obtained:. cosø - cosa + (0 + a + π - 2β) sinØ / ηλ X “Γ * '1 lj) 1 - cos (0 - a) 20 _ r. sinØ - sms - (0 4- a + ir - 2g) cosø 1 - cos (0 - a)

Just as the winding section 6 of the second half of the second section curve 1 is symmetrical about the Y axis relative to the above winding section 5, the remaining section 8 of this second half of the section curve 1 is symmetrical about the Y axis. in relation to section 7.

Both of FIG. 1, as shown by the geometric conditions explained above for the course of the different sections of the second section curve 30 l, 5.7 and 6.8 respectively, it will be seen that in the case shown, when the extension 3a of the semicircle 3 and the opening direction 4 coincide, they will said sections, 5.7 and 6.8 respectively, go smoothly with each other without any discontinuity.

35 In the embodiment of FIG. 1, the opening angle α is selected for 60 °, while the angle β from the X-axis to the starting point of the first section curve 2 for the first curve section 5.6 of the second section curve 1 is selected to 75 °. two unwinding sections 5 and 6, each of one half of the second cut-5 curve 1, exhibit a mutual overlap of 30 ° and intersect at a point on the Y-axis outside the first cut curve 2.

From the above expression (3), the distance D from the Y-axis to the end point of one half of the other 10 curve 1 can be calculated, obtaining for the value Θ = 2ir - α: D = -x = -r · ~ (3π ~ 2β) * sincc = r · iiV2 ~ 11 (5) 1 - cos (2ir - 2a) sine

For a circular cylindrical light source, the distance D will correspond to half the width of the light output aperture of the reflector, and it will be seen that by varying the angle β of a reflector fully covering the light source upwards, the smallest width determined at D = r · Ir / sina at the value β = π / 2 corresponding to the unwinding sections 5 and 6 starting from the same point on the first section curve 2, near the intersection with the Y-axis.

Similarly, the height of the reflector can be calculated from the above expressions (2) and (4) as the sum + H2 of the y-values in the said expressions for Θ = ir and 0 = 2ir - a, respectively, by inserting into the expressions (2) and ( 4) 25 one gets: H1 = r · (7Γ - β) (6) „_ sing + (3ττ / 2 - β) cosa il« - r · - \ t) ζ sin ^ a 30 which gives: H - H , + H, = r (π - S + I3? # - β) (8) 1 2 sin ^ a

From this it will be seen that for a reflector that completely covers the light source upwards, the height H will also assume its minimum value for the value β = τr / 2.

Especially for a circular cylindrical light source it can be deduced from the following considerations that the above-mentioned 145207 expression (5) will indicate the minimum width of a reflector with optimum light emission. The part of the first curve 2 enclosed by the second section curve 1 and thus transmitting light will be given by: 5 r (3π - 23) (9)

Since the surface luminance of the light source is L, the light source luminous flux for the part thus enclosed per running meters of the light source in the direction of the longitudinal axis are: 1Q φχ = ir · L · r (3ττ - 2β) (10)

An ideal reflector with optimal light emission will have the reflectance 1 so that it glows with the luminance of the light source on the flared parts. Especially for the circular cylindrical light source, the light output aperture of the entire reflector 15 will be flared when viewed within the angular space constrained by the opening boundary jets / while it will appear completely dark when viewed from directions outside this angular space.

The light output aperture, whose width is given at 2D, 20 will emit the luminous flux under these conditions: Φ _ π · L 2D (11) 2 sine

Since the reflector is assumed to be loss-free, φ'1 = Φ2 is assumed, which gives exactly the above expression (5).

25 For non-cylindrical light sources with a circular section curve as shown in FIG. 1, i.e. eg. for rotationally symmetric light sources, the conditions will be somewhat different from the purely axially symmetric case described above, since for reflectors for such light sources 30 it cannot be assumed that the entire light output aperture will be flared considering directions at the edge of the angular boundaries of the aperture boundary beams. , ie near the opening boundary jets. However, the degree of flare will also be maximum for reflectors for such light sources, so that even for these light sources, the ratio of brightness and area of the light output aperture will be optimal in the reflector design proposed by the invention.

While the mathematical conditions for designing a reflector according to the invention above are described solely by reference to the simple but very important special case where the first cut curve is circular and the second cut curve is symmetrical about the angular half-line between the two aperture boundary beams as well. The two symmetrical halves of this sectional curve have a smooth course without any discontinuity between the first waveguide section with winding parts and the second and third waveguide sections of the remaining lower parts, the following more schematically different other embodiments of the reflector of the invention are explained below.

For all those of FIG. 2-7 show that the figures show only the first sectional curve and the second sectional curve seen in a normal plane to a plane of symmetry parallel to the surface of the light output aperture, as is also the case in FIG. First

In FIG. 2, an embodiment is seen where the first cut curve 9 forms an ellipse, as will be the case, for example, for a cylindrical light source with an elliptical cross-section or a rotary ellipsoidal light source with a rotational axis substantially perpendicular to the plane of the light output aperture. In this embodiment, further, the second section curve, which is denoted in its entirety by 10, is completely asymmetric. The cut curve 10 consists at the top of a first curve section with two parts 11 and 12 in the form of unwinding to the cut surface 30 of the first surface. As with the embodiment of FIG. 1, these unwinding portions 11 and 12 intersect at a point outside the first cut curve 9, but in this case the point of intersection is not located either on a symmetry axis of the cut curve 9 or on the angular half-line 35 of the two aperture boundary beams shown at 13 and 14. Further, the second cut-off curve 10 exhibits cracks between said unwinding-shaped parts 11 and 12 and the second and third-wave sections, respectively 15 and 16 of the cut-off curve, the two unwinding-shaped parts 11 and 12 being brought down so far that the extensions of the 17 and 18, the half keys of the first cut curve 9 from the end points of the unwinding portions 11 and 12 5 do not coincide with the two aperture boundary beams 13 and 14.

In the illustrated embodiment, the ratio of the small axis to the major axis of the elliptical section curve 9 is equal to 1: 1.5, and the two unwinding portions exhibit a mutual overlap of 30 °, while the angle between the opening boundary beams 13 and 14 is 120 °.

In FIG. 3, at a and b are shown two asymmetric reflector designs for an elliptical and a circular light source cross section, respectively, as shown by sectional curves 19 and 20, respectively. In these cases, however, the unwinding portions of the second sectional curve, 21 and 22, respectively, are limited. of half-tangents, 23, 24 and 25.26, respectively, for the first cut curve, 19 and 20, respectively, which coincide with the aperture-20 boundary beams of the reflector. As in FIG. 1 and 2 there is an interlap of 30 ° between the winding-shaped parts, such that these parts intersect outside the first section curve and the angle between the opening boundary beams is also 120 ° in this case. In the same way as in FIG. 2 25, the asymmetry is obtained by the offset points of the unwinding parts on the first cut curve 19 and 20 respectively being offset from the substantially perpendicular symmetry axis of the light source surface, in both of FIG. 3 30 cases show a displacement of 15 °. For the elliptical section curve at a in FIG. 3 is the ratio of small axis to large axis in the same way as in FIG. 2 1: 1.5.

In FIG. 4, at a-c, some asymmetric reflector designs are shown, in which the unwinding portions of the second cut curve, shown in the three figures at 27, 28 and 29 respectively, start from the same point on the first cut curve, which at a and b in fig. 4 as shown at 30 and 31 is elliptical, while at c in FIG. 4 as shown at 32 is circular. The angle between the opening boundary jets is in all three cases the same as in the previous embodiments, ie. 120 °, just as the asymmetry in the same way as in Figs. 2 and 3 is shown by the fact that the starting point of the first cut curve for the unwinding parts of the second cut curve is offset 15 ° relative to the axis of symmetry substantially perpendicular to the plane of the light output opening. for the light source surface.

For the elliptical section curves 30 and 31 at a and b in FIG. 4 is the ratio of small axis to large axis in the same way as in FIG. 2 and FIG. 3a 1: 1.5,

From the mathematical explanation above it will be seen that in reflector designs as shown in FIG. 4 will achieve minimum width of the light output port in relation to the emitted light stream.

In FIG. 5, a, b and c are shown reflector designs substantially similar to the designs of FIG. 4, but where the unwound portions of the second cut curve shown at 33, 34 and 35, 20 respectively start from different points on the first cut curve shown at 36, 37 and 38, respectively, and do not intersect, thus that at the top of the light source is an area not covered by the reflector. Hereby, light can also be emitted away from the actual area 25 of the light emission, which is particularly relevant if, for example, low illumination of a ceiling surface is desired simultaneously with illumination of a table or floor surface. Further, in this embodiment, the dimensions of the reflector are obtained as a result of the fact that a smaller portion of the light source's circumference is enclosed by the reflector.

For symmetrically designed reflectors for light sources of circular cross section, FIG. 6 by a-f illustrated the possibilities explained above for allowing the 35 unwinding portions of the second intersection curve to start from a common point on the first intersection curve or from mutually displaced points on this intersection curve with or without intersection of the unwinding portions. The three options are shown for reflectors with an angle of 90 ° between the opening boundary beams at a-c and for reflectors with an angle of 120 ° between the opening boundary beams at d-f, respectively. The figures show that for a reflector with optimum light transmission, the smallest dimensions for a given angle between the opening boundary beams are obtained by leaving the unwinding portions of the second cut curve from the same point on the first cut curve. However, even smaller reflector dimensions can be obtained by not having the reflector enclose the entire light source, as also explained with reference to FIG. 5. Further, the figures show that the height and width of the reflector are dependent on the angle between the opening boundary beams.

Finally, in FIG. 7 at a and b illustrated the 15 important special cases with symmetrically designed reflectors for light sources of elliptical cross section. In this case, the first cut curve shown at 39 and 40, respectively, has the major axis perpendicular to the plane of the light output aperture, as will be the case for many 20 ellipsoid-shaped light sources, e.g. mercury lamps with fluorescent coating, ie color-corrected mercury lamps for e.g. road lighting, and high-pressure sodium lamps with diffusing flask, which also include applies to road lighting. In the embodiment of FIG. 7, the 25 unwinding portions 42 and 43 of the second cut curve 41 project from mutually displaced points on the first cut curve 39 and intersect at a point outside this cut curve. Further, the unwinding portions 42 and 43 are passed so far down around the light source that the half tangs of the first cut curve 39 from the endpoints of these portions do not coincide with the aperture boundary beams shown at 45 and 46 so that the reflection surface will exhibit a discontinuity. at the transition between the winding-shaped portions 42 and 43 and the remaining lower portions, 47 and 48, respectively.

In the embodiment of b in FIG. 7, the unwinding portions 50 and 51 of the second cut curve 49 leave from the same point on the first cut curve 40 and there is

Claims (1)

145207 smooth transition between these portions and the remaining lower portions 52 and 53, respectively, of the reflectance sectional curve, the half-tangents of the first intersection curve 40 from the end points of the unwinding portions 50 and 51 5 coinciding with the opening boundary beams 54 and 55. a predominantly mathematical and lighting theoretical explanation of various embodiments of lighting arrangements according to the invention has been provided. It will be apparent from this that, by an appropriate reflector design, within the scope of the invention, it will be possible to achieve very accurate control of the light distribution from a luminaire provided with such a reflector at the same time that the only losses occur as a result of the reflection surface does not reflect one hundred percent of all light from the light source, but will always exhibit some absorption, whereas there is no loss due to inter-reflection between light source and reflection surface. In the practical design, the reflector in a luminaire according to the invention can be provided in the usual manner with ventilation slots, and the reflection surface may optionally be hammered to smooth the light distribution. Lighting fixture, comprising a light source having a substantially axially symmetrical, closed spatial restriction surface and a reflective reflector having a reflection surface, the edge or edges of which defines a substantially planar light output aperture, the limiting surface of the light source having a plane parallel to the light output aperture. and cut by a normal plane for this axis of symmetry in a first cut curve (2, 9, 19, 20, 30-32, 36-40), while the reflection surface of the same normal plane is cut in a second cut curve (1, 10, 21, 22, 27 -29, 33-35, 41, 49) with end points located at the light exit orifice and with a substantially first curve section (2, 9, 19, 20, 30-32, 36-40) lying in the main case, consisting of two blades (5, 6, 11, 12, 42, 43, 50, 51) for the first cut curve (2, 9, 39, 40), characterized