Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
  • F21V7/00—Reflectors for light sources
  • F21V7/04—Optical design
  • F21V7/09—Optical design with a combination of different curvatures
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
  • F21V7/00—Reflectors for light sources
  • F21V7/04—Optical design
  • F21V7/08—Optical design with elliptical curvature
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
  • F21V7/00—Reflectors for light sources
  • F21V7/10—Construction
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
  • F21V7/00—Reflectors for light sources
  • F21V7/10—Construction
  • F21V7/16—Construction with provision for adjusting the curvature

Definitions

• Rotational asymmetric para-ellipsoidal and biellipsoidal reflectors for lighting installations are symmetric para-ellipsoidal and biellipsoidal reflectors for lighting installations.
• the present invention relates to rotational asymmetric para-ellipsoidal and biellipsoidal reflectors for lighting installations.
• Symmetrical projectors are provided with both trapezoidal and rotational reflectors and allow values of maximum light intensity (about 15000 candelas) to be obtained at around 0° inclination with respect to the vertical perpendicular to the glass; the light intensity of said symmetrical projectors quickly decreases moving away from 0°. Accordingly, symmetrical projectors are especially useful in sport installations with color TV shooting where a high illuminance is required and therefore, a high light intensity in a restricted area of the sport ground is desired. The reflector needs to be greatly inclined if a high light intensity in an area far away from the vertical is desired.
• Figure 25 shows a known symmetrical reflector SR inclined by an angle a, whose glass V is passed through perpendicularly by the maximum intensity ray MIR emitted by a lamp L.
• the reflector inclination ⁇ generates an upward scattered luminous flux (light pollution).
• Asymmetric projectors normally with trapezoidal reflector, allow to obtain a maximum light intensity far away from 0°, but it is significantly inferior (at most 1000-1400 candelas at an angle of asymmetry of 40°-60°).
• Figure 26 shows a known asymmetric reflector AR with an angle of asymmetry a, whose horizontal glass V is passed through by the maximum intensity ray MIR emitted by a lamp L, inclined according to said angle of asymmetry a with respect to the vertical. Note the absence of upward scattered luminous flux (light pollution).
• asymmetric projectors have a non negligible light intensity value at 0° degrees (e.g. about 250 candelas), which causes a non ideal illuminance on the ground, for example on football fields.
• E minimum minimum illuminance of the field
• E maximum maximum illuminance of the field
• E average average illuminance of the field.
• the overall maximum intensity increases at the angle of asymmetry (e.g. 40°) but the light intensity increases even more beneath the pole, i.e. the increasing of theE average and the E maximum as a result decreases the values of Ul and U2 till to reach values below the thresholds required by the rules.
• Assembled asymmetric reflectors of circular shape are known which reproduce an optical pattern given by the composition of different curvatures.
• said curvatures are overlapping conical sections reciprocally connected to reflect the light energy irradiated by the lighting installations in an optimum and continuous manner.
• Document WO0077445 describes an assembled asymmetric reflector generated by a series of hyperboles that allow the elimination of shadows, energy saving and a pleasant lighting to be provided.
• the assembled asymmetric reflector is formed of: a first section constructed along the curvature of a first hyperbole; a second section constructed along the curvature of a second hyperbole; a third section constituting an arch. Said three sections are reciprocally inclined in order to generate contiguous schemes of reflected light on a illuminated surface.
• Document EP2093482 describes a reflector comprising a light source, of the type formed of three zones: the reflector base is occupied by a parabolic surface; the end ends with an elliptical surface; a transition zone exists between the two zones. The reflector thus assembled allows the amount of reflected light combined with direct light to be controlled.
• Document EP2019255 describes a reflector formed by the combination of parabolic and elliptical sections that allow direct light and reflected light to be combined.
• the reflector shape is obtained by means of a geometrical formula based on the hyperbole and parabola parameters.
• Document EP1126210 describes a reflector of an automotive light wherein a first elliptical reflecting surface has the focus coinciding with that of a second elliptical reflecting surface, the optical axis of the first reflecting surface being inclined by a right angle with respect to that of the second reflecting surface.
• a parabolic reflecting system has the focus coinciding with the second focus of said second elliptical reflecting surface, the optical axis coinciding with the illuminance direction.
• Document GB 1183481 describes a reflector of which the surface is composed of a parabola inclined so as to intersect axis Y of a hyperbole at the common focus, and thus rotated according to its axis so as to generate a paraboloid.
• the finding is adapted to be configured in various combinations with surfaces having paraboloid, hyperboloid, cylindrical parabolic, cylindrical hyperbolic or flat shape.
• Document WO2011107901 describes an optical device comprising an area formed of a first surface having a first Bezier curve and a second surface having a second Bezier curve, said Bezier curves being arranged so that the optical device is rotational asymmetric with respect to its central axis, causing a homogeneous light distribution in horizontal and vertical direction on a predefined lighting area subtended by a certain angle.
• Document WO2010146494 describes a lighting device comprising a reflector constructed about a main axis, wherein the rear part comprises a portion rotated with respect to an axis perpendicular to said main axis, obtaining an asymmetric distribution of the light at the outlet of said rear part.
• the rear part is of conical or of parabolic shape.
• asymmetric reflectors knows the composition technique of surfaces generated by different conical curves for optimizing the light intensity and efficiency.
• a problem at the basis of the use of asymmetric reflectors is represented by the difficulty to control the direction and distribution of the light intensity in space, i.e. the practical implementation of the angle of asymmetry in project.
• the architecture of a rotational asymmetric reflector is based on: the construction of a combined curve by means of different conical sections; the rotation of the combined curve by a round angle with respect to the optical axis of the reflector; the generation of a spatial figure; the edging of the spatial figure.
• a circular asymmetric reflector requires: a forming machine of a three-dimensional solid capable of reproducing the outline of the spatial figure; three-dimensional connection and cutting means.
• the device finish is based on the choice of materials having strong reflecting features and on the application of metal coatings on the reflecting surfaces.
• the object of the present invention is to define a procedure for the construction of a projector with rotational asymmetric reflector by which the angle of asymmetry is easily controlled, i.e. constructing the reflector with the project asymmetry angle is easy.
• a second object of the present invention is to provide a projector with rotational asymmetric reflector which has maximum light intensity values similar to symmetrical projectors, and at least with the same efficiency.
• a further object of the present invention is to allow the lighting of important sport facilities and color TV shooting with distributed lighting only with asymmetric reflectors without generating light pollution, where by distributed lighting it is meant the distributed positioning of the projectors above or below the coverage of the tribunes of the stadium.
• Yet a further object of the present invention is to provide a projector with rotational asymmetric reflector with values of uniformity of illuminance complying with the rules in low and medium level football fields without increasing the height of poles and without generating light pollution.
• FIG. 1 shows a geometrical figure in a plane X, Y, in a Cartesian space delimited by three axes X, Y, Z, composed of an ellipse, symmetrical with respect to the Cartesian axes, and of two identical parabolas, symmetrical with respect to axis Y and tangent to the ellipse, related to the present invention;
• FIG. 2 shows the geometrical figure of FIG. 1 without the half constructed along the positive stretch of axis 0-X;
• FIG. 3 shows a sectional area obtained from the geometrical figure of FIG. 2 without the half constructed along the negative stretch of axis 0-Y, provided with a thickness of a sheet of material used for forming a reflector, according to the present invention
• FIG. 4 and FIG. 5 show axonometric views of a rotationally symmetric solid obtained by rotating the sectional area of FIG. 3 about axis X, according to the present invention
• FIG. 9 shows a projection view in plane X, Y of the two parts of solid of FIG. 8, the second part of said solid being translated along the plane, parallel to axis Z and inclined by an angle a, according to the present invention
• FIG. 10, FIG. 11 and FIG. 12 respectively show a projection view in plane X, Y and two axonometric views of the solid of FIG. 9 assembled with hinge fixing elements;
• FIG. 13 shows a geometrical figure in a plane X, Y', composed of a first ellipse, symmetrical with respect to the Cartesian axes, tangent to a second ellipse, inscribed to the first ellipse, related to the present invention
• FIG. 14 shows the geometrical figure of FIG. 14 without the half constructed along the positive stretch of axis 0-X;
• FIG. 15 shows a sectional area obtained from the geometrical figure of FIG. 14 without the half constructed along the negative stretch of axis 0-Y, provided with a thickness of a sheet of material used for forming a reflector, according to the present invention
• FIG. 16 and FIG. 17 show axonometric views of a rotationally symmetric solid obtained by rotating the sectional area of FIG. 15 about axis X, according to the present invention
• FIG. 21 shows a projection view in plane X, Y of the two parts of solid of FIG. 20, the second part of said solid being translated along the plane, parallel to axis Z and inclined by an angle a, according to the present invention
• FIG. 22, FIG. 23 and FIG. 24 respectively show a projection view in plane X, Y and two axonometric views of the solid of FIG. 21 assembled with hinge fixing elements;
• FIG. 25 shows a known symmetrical reflector
• FIG. 26 shows a known asymmetric reflector.
• a shape of a rotational asymmetric reflector for projector for lighting installations derives from a geometrical figure in a plane X, Y composed of an ellipse E symmetrical with respect to the Cartesian axes and of a pair of identical parabolas P, symmetrical with respect to axis Y and tangent to ellipse E in points PE1, PE2, PE3 and PE4.
• a closed curvature 1 is formed by stretches of parabola P and by stretches of ellipse E, jointed at points PE1, PE2, PE3 and PE4.
• An open curvature 2 is formed by curvature 1 without the half constructed along the positive stretch of axis 0-X. It is noted that said open curvature 2 (figure 2) consists of a parabola P with a known focus suitable for the type of light source tangent in points PE2 and PE3 to an ellipse E. Mathematically, such ellipse E is the only one to be tangent in those points once a focus FIE thereof has been set. The determination of points PE2 and PE3 and of a focus FIE of the ellipse is dictated by the value of the maximum light intensity to be obtained and by allowing the whole light reflected by parabola P to directly exit from the final reflector with a single reflection.
• a curve 3 is obtained from the open curvature 2 after the latter has been deprived of the half constructed along the negative stretch of axis 0-Y, provided with a thickness th of a sheet of malleable material used to form a reflector, according to the present invention.
• a rotationally or revolution symmetrical solid 5 is obtained by rotating curve 3 about axis X (figures 4 and 5).
• the flat curve 1 is just the intersection of plane X, Y (or of any other plane containing the axis of rotation X of the rotationally symmetrical solid 5) with the rotationally symmetrical solid 5.
• said rotationally symmetrical solid 5 is obtained by sheet turning, using especially designed turning molds.
• the rotationally symmetrical solid 5, obtained as said by sheet turning, is divided into two parts, 51 and 52, by 3D laser cutting along a cutting plane 60 which is parallel to axis Z and is inclined by an angle a with respect to axis Y (figures 6 and 7).
• Said angle a corresponds to the asymmetry angle of the maximum light intensity of the projector, which is normally in the range between 40° and 60°.
• the cutting plane 60 does not contain axis Z, but is displaced in the positive direction of axis Y by a stretch Y0 of few millimeters, useful for overlapping parts 51 and 52 as will be clearer hereinafter (figures 8-10).
• Part 52 is then rotated by about 180° and assembled to part 51 by means of connecting inserts 61, 62 such as rivets, inserted around the center of the three Cartesian axes and in the proximity of the upper overlapping zone, thereby obtaining an assembled rotational asymmetric para-ellipsoidal reflector 6 that is hereinafter referred to as para-ellipsoid 6 for simplicity.
• connecting inserts 61, 62 such as rivets
• Part 52 overlaps part 51 by a stretch OL of few millimeters (figure 10) so that the second reflecting part 52 is off axis with respect to the first reflecting part 51.
• the inserts 61, 62 also allow the inclination of part 52 with respect to part 51 to be changed approximately within a range of +/-20° with respect to the theoretical angle a.
• the connecting inserts 61, 62 constitute a hold for the housing of the reflector to the bearing support structure of the reflector (not depicted).
• the possibility of changing the inclination of part 52 allows to calibrate the photometric features of the reflector depending on the equation of ellipse E tangent to parabola P.
• the relative rotation of the part 52 with respect to the part 51 allows to eliminate the multiple reflections within the geometrical profile of para-ellipsoid 6, optimizing the luminous efficiency of the para- ellipsoid 6, i.e. it allows to prevent multiple reflections between the first reflecting part 51 and the second reflecting part 52.
• the determination of focus FIE of the ellipse is defined so that the rays directly exit from the complete final reflector with at most a single reflection on the concave reflecting surface of the para-ellipsoid 6.
• Said cutting plane 60 is cut so that the beam reflected on the reflecting surface of the second reflecting part 52 does not intercept the reflecting surface of the first reflecting part 51, i.e. the cutting plane 60 starts from a point comprised between the tangent point PE2 between parabola P and ellipse E and the vertex of parabola V and said cut ends on a point comprised between points PE3 and PE1 as shown in Figures 1-6.
• the second reflecting part 52 is advantageously off axis with respect to the first reflecting part 51 so that the rays of the light beam directly exit from the complete final reflector with at most a single reflection on the concave reflecting surface of the para-ellipsoid 6 and the rays of the light beam are reflected downwards without creating light pollution.
• the para-ellipsoid 6 may also be seen as a solid obtained from: the combination of a paraboloid 65 and an ellipsoid 66 jointed along a line 67 formed by points 68 on which common tangent planes 69 pass (figure 4), suitable deprived of the symmetrical half parts; the division into two parts, 51 and 52, of the remaining solid by a cutting plane inclined by an angle a equal to the asymmetry angle of the maximum light intensity (figures 6 and 7); the reciprocal rotation of the two parts 51 and 52 (figure 8); the assembly by means of union means 61, 62 applied along the overlapping zone of the respective edge of the two parts 51 and 52 (figures 9 and 10).
• the para-ellipsoid 6 is used in the present invention in order to implement a rotational asymmetric projector for lighting installations.
• said para-ellipsoid 6 at about 0° has a light intensity much lower than the traditional asymmetric reflectors, i.e. 150 candelas instead of the normal 250 candelas. This allows very low light intensity values to be obtained below the pole, with consequent advantages in terms of light uniformity.
• the efficiency of the para-ellipsoid 6 is substantially similar to that of the best known asymmetric and symmetrical reflectors, i.e. between 70 and 80.
• the designer wants to reduce the maximum intensity value, for example bringing it to 4500-5000 candelas from the nominal 15000 candelas without decreasing the efficiency, he may make some facets 81 on the paraboloid. The larger is the number of said facets 81, the smaller is the reduction of the light intensity.
• Para-ellipsoid 6 according to the invention therefore allows very large areas, such as football fields, to be illuminated, with high light intensities, without light pollution and high uniformity of the illuminance.
• the cutting angle a corresponds to the asymmetry angle a between an axis corresponding to the maximum light intensity beam of the projector projected and to the angle between a vertical straight line 71, i.e. an axis orthogonal to an horizontal light emission plane 70, adapted to contain the projector glass, and the maximum light intensity ray 72 emitted by the reflector (figure 10), thus ensuring a reduction of the production faults and a consequent easiness of serial production of the reflectors.
• hereinafter is the implementation process related to the combination of a greater ellipsoid and a smaller ellipsoid, jointed along tangent planes suitable deprived of the symmetrical half parts with respect to the symmetry plane of the smaller ellipsoid.
• a second embodiment of the circular asymmetric projector according to the present invention derives from a geometrical figure in plane X, Y composed of an ellipse El, symmetrical with respect to the Cartesian axes, and of an ellipse E2, tangent to ellipse El in points E1E2', E1E2".
• a closed curvature 7 is formed by stretches of ellipse El and by stretches of ellipse E2, jointed at points E1E2', E1E2".
• the figures composed of an open curvature 8, a sectional areas 9, a rotationally or revolution symmetrical solid 10 and a rotationally symmetrical solid 11 allow an assembled rotational asymmetric bi-ellipsoidal (with dual ellipse) reflector 12 (which hereinafter will be referred to simply as biellipsoid for simplicity) to be obtained in the same way as for constructing the assembled rotational asymmetric para-ellipsoidal reflector 6.
• axis Y (figures 14-21) does not correspond to axis Y' of figure, but to the smaller axis of ellipse E2.
• said open curvature 8 (figure 14) consists of a first ellipse El with a focus suitable for the type of light source tangent in points E1E2' and E1E2" to a second ellipse El.
• ellipse E2 is the only one to be tangent in those points once a focus F1E2 thereof has been fixed.
• the determination of points E1E2' and E1E2" and of a focus F1E2 of the ellipse is dictated by the value of the maximum intensity to be obtained and by allowing the whole light reflected by the first ellipse El to directly exit from the final reflector with a single reflection.
• biellipsoid 12 is formed of parts 111 and 112 first separated by 3D laser cutting with cutting angle a corresponding to the asymmetry axis of maximum light intensity of the reflector, and then assembled by means of connecting inserts 121, 122 after rotating part 112 by about 180°.
• the connecting inserts 121, 122 such as rivets or screws, are inserted around the center of the three Cartesian axes, also allowing the inclination of part 112 to be varied with respect to part 111 approximately within a range of +/-20° with respect to the theoretical angle a, an overlapping of few millimeters occurring between the two parts as in the above-described case of the para- ellipsoid 6.
• inserts 121, 122 constitute a hold for the reflector housing to the bearing support structure of the reflector (not depicted).
• the biellipsoid reflector 12 has the same advantages as the para-ellipsoid reflector 6, with an increase in efficiency due to the fact that the light rays converge towards the focus of the first ellipse El with limited multiple reflection phenomena on the second ellipse E2.
• Biellipsoid 12 may also be seen as a solid obtained from: the combination of two ellipsoids 125, 126 jointed along a line 127 formed by points 128 on which common tangent planes 129 pass (figure 16), suitable deprived of the symmetrical half parts; the division into two parts, 111 and 112, of the remaining solid by a cutting plane inclined by an angle a equal to the asymmetry angle of maximum light intensity (figures 18, 19); the reciprocal rotation of the two parts 111 and 112 (figure 20); the assembly by means of union means 121, 122 applied along the overlapping zone of the respective edge of the two parts 111 and 112 (figures 21 and 22).
• an assembled asymmetric reflector according to the present invention is preferably industrially made by means of: forming machines of three-dimensional solids capable of reproducing the outline of the spatial figures; three-dimensional welding and cutting means; processes for finishing and coating the reflecting surfaces.
• the forming of the rotationally or revolution symmetrical solid 5, 10 is preferably carried out by sheet turning.
• the sheet turning implies the deformation of a metal disc (steel, iron, brass, copper, aluminum, etc.) rotating on a pin having the axial-symmetrical shape of the concave reflecting surface of the rotationally symmetrical solid 5, 10.
• the machinery that allows this type of modeling is a lathe that rotates the metal disc on which a tool acts, which deforms the initial disc up to making it take the desired shape relative to the rotationally symmetrical solid 5, 10.
• the rotationally symmetrical solid 5, 10 is cut by three-dimensional laser cutting technology.
• the increase in the lighting efficiency is obtained by resorting to techniques of metallization, anodizing and buffing of the reflecting metal surfaces constituting parts 51, 52 and 111, 112.
• An assembled rotational asymmetric reflector of lighting installations implemented according to the present invention relates to any type of lamp and appliance, in particular having a power from 20 to 2000W, with long arch and short arch.

Landscapes

• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Non-Portable Lighting Devices Or Systems Thereof (AREA)
• Optical Elements Other Than Lenses (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

Family

ID=46548631

Family Applications (1)

Country Status (4)

Citations (9)

• 2012
  • 2012-03-27 IT IT000488A patent/ITMI20120488A1/it unknown
• 2013
  • 2013-03-22 EP EP13711403.9A patent/EP2831495B1/fr not_active Not-in-force
  • 2013-03-22 EA EA201491772A patent/EA026835B1/ru not_active IP Right Cessation
  • 2013-03-22 WO PCT/EP2013/056051 patent/WO2013144005A1/fr not_active Ceased

Patent Citations (9)

Also Published As

Similar Documents

Legal Events