The present invention relates to a reflector lamp comprising a light source and a reflector defined by a surface of revolution around an axis and having an outlet.

Background of the invention

Reflector lamps of this kind are commonly used in various consumer devices, as well as in automotive industry. They may also have a form of LED lamps having a socket providing mechanical support and electrical connections.

Publication US6585397 discloses a reflector lamp comprising a light source lamp placed at the focal point of a reflector made up of a first parabolic reflector designed for reflecting light rays coming from the light source lamp to be outputted as light rays parallel to the optical axis, second parabolic reflector designed for reflecting light rays coming from the light source lamp as outwardly inclined parallel light rays, and circular truncated conic reflector for reflecting light rays coming from the second parabolic reflector and outputted as light rays parallel to the optical axis. In this fashion, light rays that cannot be outputted due to being in the shadow of the spherical light source lamp can be outputted as light rays parallel to the optical axis.

Publication W02008009166 discloses a light-emitting diode illuminating device that comprises a light-modulated hood, a reflector hood, and a variable focus lens, which are located in front of the light-emitting diode. The light emitted from the diode is firstly modulated by the light-modulated hood whose shape is any one of an oblique cone, a paraboloid and an ellipsoid, then reflected by the reflector hood whose shape is any one of a cylinder, a paraboloid and a cone, and finally projected outward through the lens.

Publication WO2015060450 discloses an illuminating instrument with a planar light source having a planar light emitting surface orthogonal to a center axis and a reflector that reflects light from the light emitting surface at a reflecting surface with the center axis as a reference. The reflecting surface has a first reflecting surface that has a parabolic surface shape formed by rotation centered on the center axis of one part of a first parabolic line, which has the center axis as an axis of symmetry, and a second reflecting surface that has a parabolic surface shape formed by rotation centered on the center axis of one part of a second parabolic line, which has a center axis parallel to the center axis as an axis of symmetry.

Publication CN201215596 discloses a compound parabolic condenser for a solar optical fiber lighting system, which comprises a primary composite paraboloidal condenser composed of a section of two parallel parabolic segments crossing each other, with their foci separated by some section, which are rotated around the axis crossing the middle of and parallel to this section. The condenser increases the concentration ratio of natural lights that it receives.

Relevant constructions of condensers and reflectors having compound parabolic or other surfaces of revolution with a discontinuity at the axis of revolution are disclosed in publications CN101840067, GB448412, or DE3312200.

Common problems of reflector lamps of this kind include uneven distribution of light, frequently with a hot spot in the center of the light source, as well as sensitivity to the tolerance to the position of the light source.

It has been the object of the present invention to provide a reflector lamp that would be devoid of the aforementioned problems. of the invention

The invention provides a reflector lamp of the kind mentioned in the outset that is characterized in that the reflector has an inner conical section that widens into a parabolic section, wherein the light source is disposed substantially at the inlet and in the center of said inner conical section defining a virtual focal point of the reflector; said parabolic section is defined by generatrices having a circle of the focal points located outside of the reflector at the side of said inner conical section; said inner conical section is configured to reflect light rays towards said parabolic section; said parabolic section is configured to reflect light rays towards a light ring of the outlet having an inner diameter and an outer diameter corresponding to the outer diameter of the reflector; and said inner conical section reflects light with an intensity up to a predefined light intensity of said light source.

Preferably said parabolic section further widens into an outer conical section, wherein said inner conical section is configured to reflect light rays also towards said outer conical section; and said outer conical section is configured to reflect light rays towards said light ring of the outlet.

Preferably the inclination angle of said inner conical section is within the range of 1 to 10 degrees.

Preferably the inclination angle of said outer conical section is within the range of 1 to 10 degrees.

Preferably the radial offset between the virtual focal point of the reflector and said circle of the focal points of the parabolic section is 2 to 4 times bigger than the reflector outer diameter.

Preferably the axial offset between the virtual focal point of the reflector and said circle of the focal points of the parabolic section is 2 to 4 times bigger than the reflector outer diameter.

Preferably the axial offset between said circle of the focal points and the minimum of the generatrix of the parabolic section is 1 to 3 times bigger than the reflector height.

Preferably said inner conical section reflects light having intensity amounting up to 70% of the maximal light intensity of said light source.

Preferably said light source is a planar light source providing an oval radiation pattern.

Preferably said light source has a form of a light emitting diode.

Brief description of drawings

The invention shall be described and explained below in connection with the attached drawings in which:

Fig. 1 is a schematic axonometric view of an embodiment of a reflector lamp according to the present invention;

Fig. 2 is a schematic cross-sectional view of the embodiment of the reflector lamp shown in Fig. 1 and a diagram of the reflector specular reflection;

Fig. 3 illustrates the geometry of a parabolic section of a reflector according to the present invention; Fig. 4 illustrates the geometry of a reflector according to the present invention; and Fig. 5 illustrates a radiation pattern of a light source of the reflector lamp shown in Fig. 1.

Detailed of preferred embodiment

Figs. 1-2 show an embodiment of a reflector lamp according to the present invention comprising a housing 2 and a light source 1 disposed within the housing 2. In this embodiment the light source 1 has a form of a light emitting diode (LED) featuring an oval radiation pattern shown in Fig. 5.

The housing 2 has an internal surface of revolution around an axis A defining a reflector 3 having an inner conical section 31 and a parabolic section 32. In this embodiment the reflector 3 is also provided with an outer conical section 33. The inner conical section 31 widens into the parabolic section 32 and the light source 1 is located at its inlet and in its center defining a virtual focal point 34 of the reflector 3. The parabolic section 32 widens into an outer conical section 33 that widens into an outlet 35 of the reflector 3. In this embodiment the outlet 35 refers to a surface delimiting the outer conical section 33, as the space within the reflector 3 is open. In other embodiments the outlet 35 could be an element made of plastic, glass or any other appropriate transparent or translucent material.

As shown in Fig. 3 the parabolic section 32 is defined by generatrices 322 having a circle 321 of the focal points 323 located outside of the reflector 3 at the side of the inner conical section 31. By placing the light source 1 above the circle 321 of the focal points 323 a significant tolerance to the position of the light source 1 is achieved.

Detailed geometry of a reflector 3 according to the present invention is shown in Fig. 4. The reflector has a height h that is divided into the heights h31-h33 of each section 31 -33. The inner conical section 31 and the outer conical section 33 are inclined respectively by angles a and [3 with respect to the axis of revolution A. The angles a and [3 are chosen within the ranges of 1 to 10° (degrees), in dependence of the radiation pattern of the employed light source 1 and the entire geometry of the reflector 3. Each section 31 , 32, 33 has a certain critical angle, respectively y1 , Y2, y3- The critical angle y1 of the inner conical section 31 is the angle below which rays emitted from the virtual focal point 34 of the reflector 3 are reflected towards the parabolic section 32 or the outer conical section 33. Rays emitted by the light source 1 at angles within the range y1 to y2 are reflected by the parabolic section 32, rays emitted at angles within the range y2 to y3 are reflected by the outer conical section 33, while rays emitted at angles within the range y3 to 90 degrees are emitted outside of the reflector 3. Both the parabolic section 32 and the outer conical section 33 are configured to reflect light towards a light ring 351 of the outlet 35 (cf. Fig. 2).

The light ring 351 has an inner diameter D1 and an outer diameter corresponding to the outer diameter D of the reflector 3 that is the diameter of the outlet 35. The radial width (D-D1) of the light ring 351 is adjusted to the radiation pattern of the light source 1 (cf. Fig. 5) and defined by the geometry of the inner conical section 31 , the parabolic section 32, and the outer conical section 33 (if present), and the reflection coefficient of the reflector 3.

An inner diameter d of the reflector 3 lies at the level of the virtual focal point 34. The virtual focal point 34 is displaced with regard to the circle 321 of the focal points 323 by a radial offset r and axial offset a that, along with the angle y1 and the height 31 of the inner conical section 31 define a parabolic section parameter f, that is the axial offset of the focal point 323 with respect to the minimum of the generatrix 322 of the parabolic section 32. Both radial r and axial offset a are selected to be 2 to 4 times bigger than the reflector outer diameter D in dependence of the radiation pattern of the employed light source 1 . The parabolic section parameter f is selected to be 1 to 3 times bigger than the reflector height h.

As illustrated in Fig. 2 and Fig. 5 the height h31 and the critical angle y1 of the inner conical section 31 are selected to enable the inner conical section 31 to gather low intensity rays. For the radiation pattern shown in Fig 5 and the embodiment of the reflector geometry shown in Fig. 2 the critical angle y1 amounts about 28 degrees to gather rays below about 62% intensity of the light source 1 . As shown in Fig. 2 these rays are reflected by the inner conical section 31 and directed towards the parabolic section 32 or the second conical section 33. The critical angle y2 amounts about 43 degrees to gather rays between 62% and 83% intensity of the light source 1 , and the critical angle y3 amounts about 53 degrees to gather rays between 83% and 92%intensity. Higher intensities are emitted directly outside of the reflector 3.

The above embodiment of the present invention is merely exemplary. The figures are not necessarily to scale and some features may be exaggerated or minimized. These and other factors however should not be considered as limiting the spirit of the invention, the intended scope of protection of which is indicated in appended claims.

List of reference numerals

A axis of revolution h reflector height d reflector inner diameter

D reflector outer diameter

D1 inner diameter of the light ring of the outlet a inner conical section inclination

[3 outer conical section inclination y1 inner conical section critical angle y2 parabolic section critical angle y3 outer conical section critical angle f parabolic section parameter a axial offset r radial offset

1 . light source

2. housing

3. reflector

31 . inner conical section

32. parabolic section

321 . circle of the focal points

322. parabolic section generatrix

323. focal point

33. outer conical section

34. virtual focal point

35. outlet

351 . outlet light ring