Lighting device, corresponding lamp and method
View Patent ↗A lighting device, which may be employed e.g. as a retrofit bulb for vehicle lamps, includes a light radiation source, e.g. a LED source, and a beam-narrowing optical system facing the light radiation source, for propagating a narrowed light radiation beam of the source along a longitudinal axis of the device. Arranged distally of the beam-narrowing optical system along the longitudinal axis, there is provided: a light reflector, a light-driving lens, a filament-like body including annular reflective surfaces extending around the longitudinal axis and exposed to light radiation from the light radiation source propagated through the light reflector and the light-driving lens, a distal mirror member having a reflective surface facing towards the filament-like body, to reflect light radiation towards annular reflective surfaces in the plurality of annular reflective surfaces. The light radiation reflected by the annular reflective surfaces of the filament-like body is spread radially from the longitudinal axis.
1. A lighting device, including:
an electrically powered light radiation source,
a beam-narrowing optical system facing the light radiation source and propagating a narrowed light radiation beam from the light radiation source along a longitudinal axis of the lighting device, and
arranged distally with respect to the beam-narrowing optical system and along the longitudinal axis, a cascaded arrangement of:
a light reflector,
a light-driving lens,
a filament-like body including a plurality of annular reflective surfaces extending around the longitudinal axis and exposed to light radiation of the light radiation source propagated through the light reflector and the light-driving lens, and
a distal mirror member having a reflective surface towards the filament-like body to reflect light radiation towards annular reflective surfaces in said plurality of annular reflective surfaces,
wherein light radiation reflected by said annular reflective surfaces of the filament-like body is spread radially and outwardly with respect to the longitudinal axis of the lighting device.
2. The lighting device of claim 1 , wherein the beam-narrowing optical system includes at least one planar-convex lens having a planar surface towards the light radiation source.
3. The lighting device of claim 1 , further including a gap between the light radiation source and the beam-narrowing optical system.
4. The lighting device of claim 1 , wherein the light radiation source includes an array of light-emitting elements.
5. The lighting device of claim 4 , wherein the beam-narrowing optical system includes an array of optical elements coupled with respective light-emitting elements of the light radiation source.
6. The lighting device of claim 1 , wherein the light reflector includes an ellipsoidal reflective surface having a first focus in a region of the light radiation source and a second focus in a region of the filament-like body.
7. The lighting device of claim 1 , wherein the light reflector includes a reflective surface having at least one of a first or a second portion focusing light radiation of the light radiation source along the filament-like body.
8. The lighting device of claim 1 , wherein the light radiation source includes a light-reflective package of a light colour.
9. The lighting device of claim 1 , wherein the light-driving lens includes:
a convex surface towards the light reflector; and
a tapered surface towards, and carrying, the filament-like body.
10. The lighting device of claim 1 , wherein the filament-like body includes a spindle-like body having said annular reflective surfaces staggered along a length thereof, and said annular reflective surfaces adjoin each other.
11. The lighting device of claim 1 , wherein the distal mirror member includes a body which provides a shield for countering light propagation along the longitudinal axis distally with respect to the mirror member.
12. The lighting device of claim 1 , wherein the light radiation source includes at least one LED source with blue emission and phosphor conversion to visible light.
13. A light including:
a lighting device according to claim 1 , and
a casing for the lighting device, the casing including at least one light-permeable portion for emitting light radiation from the lighting device.
14. A method of providing a lighting device, the method including:
providing an electrically powered light radiation source,
arranging a beam-narrowing optical system facing the light radiation source and propagating a narrowed light radiation beam from the light radiation source along a longitudinal axis of the device, and
arranging distally with respect to the beam-narrowing optical system and along the longitudinal axis, a cascaded arrangement of:
a light reflector,
a light-driving lens,
a filament-like body including a plurality of annular reflective surfaces extending around the longitudinal axis and exposed to light radiation of the light radiation source propagated through the light reflector and the light-driving lens, and
a distal mirror member having a reflective surface towards the filament-like body to reflect light radiation towards annular reflective surfaces in said plurality of annular reflective surfaces,
wherein light radiation reflected by said annular reflective surfaces of the filament-like body is spread radially and outwardly with respect to the longitudinal axis of the lighting device.