DE102011087308A1 - Lighting device with reflector, lens and aperture - Google Patents

Abstract

The lighting device (11) has a reflector (13) which can be illuminated by means of at least one light source (12), in particular a light-emitting diode, a lens (14) arranged downstream of the reflector (13) and a diaphragm interposed between the reflector (13) and the lens (14) (15), wherein the diaphragm (15) has a rear side (18, 18a) facing the reflector (13) and a reflective front side (19) facing away from the reflector (13), and the lighting device (11) is arranged and arranged for this purpose is to illuminate the front side (19) of the diaphragm (15) and from there reflect light (L) into the lens (14).

Description

The invention relates to a lighting device comprising a reflector which can be illuminated by means of at least one light source, in particular a light-emitting diode, a lens arranged downstream of the reflector and a diaphragm interposed between the reflector and the lens. The invention also relates to a method for operating a lighting device, the method comprising at least illuminating a reflector by means of at least one light source and blocking a part of the light emitted by the reflector by means of a rear side of a diaphragm. The invention can be used particularly advantageously for vehicle lighting devices, in particular headlights.

For headlamps for cars and trucks, a diaphragm is brought into a beam path between a reflector and a lens of the headlight to produce a low beam. The diaphragm blocks a portion of the light rays passing from the reflector to the lens, resulting in a sharp cut-off in the light emission pattern generated behind the lens in the far field. However, it may be desired, e.g. to increase the visibility of the headlamp, to diffuse the generally dark area diffuse. For this purpose, it is known to modify a light entrance or light exit surface of the lens by Lichtablenkstrukturen that at least slightly throws light into the generally dark area. Light deflecting structures may e.g. Include depressions or rings.

It is the object of the present invention to overcome the disadvantages of the prior art at least partially, and in particular to provide a lighting device which can provide scattered light in a space region shaded by an aperture in a particularly simple and / or photometrically flexible manner.

This object is achieved according to the features of the independent claims. Preferred embodiments are in particular the dependent claims.

The object is achieved by a lighting device comprising a reflector which can be illuminated by means of at least one light source, a lens connected downstream of the reflector and an aperture connected to the reflector and the lens, the aperture being a side facing the reflector, hereinafter also referred to as a "backside", and a facing away from the reflector, reflective side, hereinafter also referred to as "front", and the lighting device is arranged and arranged to illuminate the front of the aperture and from there to reflect light into the lens.

It is exploited that the light reflected from the front of the aperture light can fall into another region of the lens and / or at a different angle in the lens as in a lighting directly by means of the reflector. As a result, the light reflected from the front side of the diaphragm can also be radiated into spatial regions which are shaded by the diaphragm. Consequently, the provision of the desired scattered light is achieved by a simple reflectivity of the previously unused front of the aperture. On a Gestalt modification of the front or back of the lens with Lichtablenkstrukturen can be omitted.

The reflector facing the rear side of the aperture is in particular a side which can be irradiated or illuminated directly from the reflector. Analogously, the front side of the diaphragm facing the lens can in particular be a side which can not be directly irradiated or illuminated by the reflector.

The shape of the aperture is basically arbitrary. For example, the panel can be designed plate-shaped, with the front and the back of the panel correspond to the two main sides of the plate. Such a diaphragm can in particular be arranged on or in a light exit opening of the reflector or outside the reflector.

However, the aperture can be e.g. also be shaped so that its back is oriented angled to the front, e.g. is perpendicular to it. For example, the backside may be in the reflector, e.g. horizontally, and form, for example, at least part of the inside of the reflector. For example, the back may form a floor or floor area located in a main plane of the reflector.

The backside may be generally light absorbing or reflective. The front side can generally face the lens, in particular be aligned parallel or with a slope of in particular not more than 20 ° to a rear side of the lens.

The light source can in particular emit UV light, visible light and / or IR light. The light source may in particular be a semiconductor light source. Preferably, the at least one semiconductor light source comprises at least one light-emitting diode. If several LEDs are present, they can be lit in the same color or in different colors. A color can be monochrome (eg red, green, blue etc.) or multichrome (eg white). Also, the light emitted by the at least one light emitting diode, an infrared light (IR-LED) or an ultraviolet light (UV-LED). Several light emitting diodes can produce a mixed light; eg a white mixed light. The at least one light-emitting diode may contain at least one wavelength-converting phosphor (conversion LED). The phosphor may alternatively or additionally be arranged remotely from the light-emitting diode ("remote phosphor"). The at least one light-emitting diode can be in the form of at least one individually housed light-emitting diode or in the form of at least one LED chip. Several LED chips can be mounted on a common substrate ("submount"). The at least one light emitting diode may be equipped with at least one own and / or common optics for beam guidance, for example at least one Fresnel lens, collimator, and so on. Instead of or in addition to inorganic light-emitting diodes, for example based on InGaN or AlInGaP, it is generally also possible to use organic LEDs (OLEDs, for example polymer OLEDs or small molecule OLEDs). Alternatively, the at least one semiconductor light source may, for example, comprise at least one diode laser.

It is an embodiment that the lens has at least one partially transparent mirrored region, on which light emitted by the reflector can be partially reflected onto the front side of the diaphragm. In this embodiment, therefore, the light emitted by the reflector light impinges on the at least one partially transparent mirrored region of the lens and is partially transmitted as usual and partially reflected on the at least partially reflective front of the aperture. From the front of the aperture, the light is reflected back into the lens, but at a different angle and / or in a different area of the lens. Consequently, the stray light can be provided by two simple mirrors. The partially transparent mirrored area may, for example, have a partially transparent mirror layer. A proportion or relative brightness of the scattered light can be easily achieved by adjusting a property of the partially transmissive mirror layer, e.g. their thickness.

It is still an embodiment that the lighting device has at least one additional light source, in particular semiconductor light source, for illuminating the front side of the panel. In this embodiment, the light emitted by the at least one additional light source (in particular directly) strikes the at least partially reflective front side of the diaphragm and is reflected from there into the lens. As a result, adaptation of the lens can be completely dispensed with, e.g. on a provision of front troughs, etc. or on a rear partially transparent mirrored area. In addition, a form of scattered light distribution can be adjusted particularly flexibly. Also, a light intensity of the scattered light is independent of a light intensity of the 'regular', emitted by the reflector light adjustable.

It is a further embodiment that the light from the front side of the diaphragm can only be reflected in a spatial region (in particular region of the lens) which is shaded by the rear side of the diaphragm. Consequently, an additional region of the Lichtabstrahlmusters is generated by the diaphragm, which is independently of the light emission pattern generated directly by the reflector shapable.

In particular, a brightness of the additional region of the light emission pattern may be adjustable, e.g. by the brightness of the light generated by the at least one additional light source. If this brightness is small as compared with the bright area generated by the reflector, the additional area of the light emitting pattern may be used as a weak light scattered area.

However, if this brightness is no longer low in comparison with the bright area produced by the reflector, a functionally different light emission pattern or light function can be provided, e.g. an off-road light, a low beam or a daytime running light. Thereby, therefore, a two-function operation can be provided. In particular, at a high brightness of the light generated by the at least one additional light source, the cut-off line can be resolved, if desired.

It is yet another embodiment that light from the front of the aperture is both in a shaded by the back of the aperture space area (in particular region of the lens) and in a illuminated by the reflector space (in particular portion of the lens) is reflected. Thus, a form of the light emission pattern can be even more modified, in particular for providing a two-function operation. In particular, so the chiaroscuro limit can be resolved particularly effectively, if desired.

For example, a particular two-function operation may be such that, in a first function in a light emitting pattern of the lighting device, the brightness of the light generated by the additional light source (s) is significantly less than the brightness of the at least one light source for illuminating the reflector generated light. The scattered light is thus considerably weaker than the 'regular' light, which corresponds in particular to a conventional low-beam operation. In a second function, in a light emitting pattern of the lighting device, the brightness of the light source (s) generated by the additional light source (s) may be increased Light can not be negligible compared to the brightness of the light generated by the at least one light source for illuminating the reflector light. As a result, an additional Lichtabstrahlmuster be generated, for example, no longer has to have a light-dark border. Such a second function may be, for example, a high beam function or a daytime running light function.

It is also an embodiment that the at least one light source for illuminating the reflector is dimmable. It is thus also possible to provide light-attenuating light emission patterns or light functions in a targeted manner, e.g. a daytime running light.

It is also an embodiment that the front of the panel is designed diffusely reflective. This helps to uniformly distribute the reflected light to the back of the lens. In addition, such a possibly inhomogeneous reflectance of the front of the aperture can be adjusted.

It is also an embodiment that the front of the panel is covered with at least one phosphor, in particular with at least one phosphor layer. As a result, a diffusely scattered mixed light as scattered light, etc. can be generated in a particularly simple manner. The mixed light is composed of the primary light originally generated by the at least one additional light source and the wavelength-converted secondary light generated by the at least one phosphor from the primary light. Depending on the density, thickness, etc. of the phosphor, the degree of conversion of primary light to secondary light can be adjusted and, if necessary, only secondary light can be radiated onto the lens.

It is still an embodiment that the reflector (or its reflective inner side or inner wall) has an at least approximately ellipsoidal basic shape. Thus, a light emission pattern of the reflector is achieved, which can be particularly limited locally and thus allows a particularly compact and high-beam shaping arrangement. In addition, the aperture can easily allow a sharp, high-contrast cut-off line. However, the lighting device is not limited to this and may be e.g. also have a parabolic or free-form or free-space shaped reflector.

It is yet a further embodiment that the reflector has a half-shell reflector or is designed as such. This results in a particularly inexpensive and compact design, in particular since often only one half of the emission pattern of a solid shell reflector is required and the light emission pattern advantageously has a longest width at the cut-off line. However, the reflector is not limited to this and may in particular comprise any suitable type of hollow reflector, e.g. also a full shell reflector.

It is also an embodiment that the aperture has a cut-off edge (i.e., a border for creating the cut-off line) on a principal plane of the reflector. This gives a sharp cut-off at the widest part of the light emission pattern.

The lighting device may generally comprise one or more optical elements connected downstream of the shell reflector, e.g. one or more lenses, additional reflectors, translucent covers, etc.

It is also an embodiment that the lighting device is a vehicle lighting device, in particular headlights. In particular, in this case, the light-dark boundary and the scattered light generation or a two-function operation are advantageously used, in particular at least for generating a low beam.

The type of vehicle is not limited and may include, for example, waterborne vehicles (ships, etc.), airborne vehicles (airplanes, helicopters, etc.), as well as land based vehicles (e.g., cars, trucks, motorcycles, etc.). In particular, electric bikes ("e-bikes") are preferred.

The object is also achieved by a method for operating a lighting device, wherein the method comprises at least: illuminating a reflector by means of at least one light source; Blocking a part of the light emitted by the reflector by means of a rear side of a diaphragm; Irradiating a lens by means of another part of the light emitted by the reflector; and irradiating a reflective front surface of the shutter with light so that the light thereof is incident at least in a space portion of the lens shaded by the back side of the shutter. The method gives the same advantages as the lighting device and can be configured analogously.

The above-described characteristics, features, and advantages of this invention, as well as the manner in which they will be achieved, will become clearer and more clearly understood in connection with the following schematic description of exemplary embodiments which will be described in detail in conjunction with the drawings. In this case, the same or equivalent elements may be provided with the same reference numerals for clarity.

1 shows a sectional side view of a first vehicle lighting device;

2 shows the first vehicle lighting device as a sectional view in plan view;

3 shows in front view of a generated behind the vehicle lighting device Lichtabstrahlmuster; and

4 shows a sectional side view of a second vehicle lighting device.

1 shows a sectional view in side view of a vehicle lighting device 11 , which is particularly suitable for use as a headlight of an electric bike. 2 shows the vehicle lighting device 11 in a top view.

The vehicle lighting device 11 has at least one light generating unit 12 , an approximately ellipsoidal reflector 13 , a lens 14 and a panel 15 on. These elements can be accommodated in a dust- and / or moisture-proof housing (not illustrated).

The reflector 13 optically downstream lens 14 has an aspherical shape and is rotationally symmetrical about its optical axis O. The optical axis O is shown lying horizontally here. The Lens 14 thus has a plano-convex basic shape, with a convex front surface 16 has a spherical shape and a flat, rear surface ("back") 17 is perpendicular to the optical axis O, which here coincides with the x-axis. The Lens 14 consists of PMMA. A diameter of the lens 14 perpendicular to the optical axis O (which is a circle diameter of the plane surface 17 corresponds to) is about 50 mm at a thickness along the optical axis O of about 20 mm. A length of the vehicle lighting device 11 is in particular between 80 mm and 90 mm.

The aperture 15 is partially in a beam path between the reflector 13 and the lens 14 connected. The optically between the reflector 13 and the lens 14 switched aperture 15 has a reflector 13 facing, through the reflector 13 directly illuminable or illuminable side ("back") 18 on. The aperture 15 also has a reflector 13 facing away, through the reflector 13 not directly illuminable or illuminable side ("front") 19 on. Thus, part of the reflector 13 radiated light from the back 18 the aperture 15 blocked and partially directly on and through the lens 14 blasted.

An upper edge, the cut-off edge 10 , the iris 15 touches the optical axis O. The aperture 15 generated by means of the cut-off edge 10 in the from the lens 14 projected image or light emission pattern (see 3 ) the cut-off line, as prescribed, for example, for the operation of an electric bike on the road. At the intersection between the optical axis O and the cut-off edge 10 may be a second (outer) focus F2 of the reflector 13 are located. The second focal point F2 may in particular, in particular a focal point of the lens 14 correspond.

The backside 18 the aperture 15 is basically opaque, especially light absorbing, designed while the front 19 is designed reflective. In this variant is the aperture 15 designed as a vertical plate.

The reflector 13 is here purely exemplary configured as a half-shell reflector with an approximately ellipsoidal free-shaped reflection surface. A front edge 20 of the reflector 13 is curved laterally forward and runs out in peaks T, as in 2 shown. A lower edge of the reflector 13 lies on the level H, which is also a main plane of the reflector 13 represents. The reflector 13 has a base body made of plastic with a specular reflective reflecting surface on its inside.

A horizontal plane H, in which the optical axis O of the lens 14 mentally divides the represented space into an upper half space OH and a lower half space UH. While the lens 14 is half in the upper half space OH and the other half in the lower half space UH, is the reflector 13 in the upper half space OH and the aperture 15 in the lower half space UH.

The reflector 13 has one of the reflector 13 vaulted inner focal point F1 and an outer focal point (o.Fig.), Which between the reflector 13 and the lens 14 lies on. Consequently, only a part of the rear side lying in the lower half space UH becomes so 17 the lens 14 irradiated. That behind the lens 14 (ie in the direction of the x-axis) projected light emission pattern has a bright-dark boundary at its upper edge in the far field, while the Lichtabstrahlmuster at the output of the reflector 13 has a lower cut-off line.

In the region of the inner focal point F1 is a light exit surface (o.Fig.) Of the light generating unit 12 , The inner focus F1 can also be regarded as a focal spot due to the not negligible light exit surface. The light generation unit 12 points here white light or blue-yellow mixed light emitting conversion light-emitting diodes 21 on. The conversion LEDs 21 For example, a diffuser can be connected downstream. With activated light-emitting diodes or activated light-generating unit 12 is at the light exit surfaces of the LEDs 21 leaking light L in the reflector 13 blasted. The reflector 13 is therefore the light generation unit 12 optically downstream.

The backside 17 the lens 14 is at least in this of the reflector 13 Directly irradiated part or area in the lower half space UH partially reflecting mirrored, for example, by a there applied partially transparent mirror layer. The semitransparent mirror layer may be, for example, a thin silver layer. Thus, part of the reflector 13 on the back 17 reflected light L, on the reflective front 19 the aperture 15 , From there, the light L is returned to the lens 14 blasted. Consequently, the lighting device 11 arranged and furnished, the front 19 the aperture 15 to illuminate and from there light L into the lens 14 to reflect. Because the aperture 15 another position and possibly position or orientation in space than the reflector 13 , that may be from the aperture 15 on the lens 14 reflected light a different area of the lens 14 Irradiate (eg, a lying in the region of the upper half space OH part of the lens 14 ) and / or at a different angle in the lens 14 irradiate, leaving behind the lens 14 Projected image or Lichtabstrahlmuster in the far field at least one additional, comparatively weakly illuminated, scattering area, in particular above the cut-off line or in the through the back 18 the aperture 15 darkened area.

In one variant, the aperture 15 a (dashed lines drawn) back 18a on which horizontally on the main plane H of the reflector 13 lies and thus at least partially represents its soil. The backside 18a is perpendicular to the front 19 , In particular, in this variant, the back 18a eg also reflective, especially mirrored, be.

3 shows in frontal view along the optical axis O behind the lens 14 through the vehicle lighting device 11 a light emission pattern M generated in the far field. A lower region M1 of the light emission pattern M located below the main plane H has a sharp light / dark boundary G at its upper edge R1 and is generated by light directly from the reflector 13 in the lens 14 running. An upper region M2 of the light emission pattern M located above the main plane H adjoins the light-dark boundary G at its lower edge R2 and is generated by light coming from the reflector 13 first on the front 19 the aperture 15 and from there into the lens 14 running. A relative brightness of the areas M1 and M2 can be determined by the reflectance of the partially transparent mirrored back 17 the lens 14 be adjusted, the shape of the upper portion M2, for example, by the shape (eg, curvature, etc.) of the front 19 the aperture 15 ,

4 shows a sectional view in side view of a vehicle lighting device 31 , In contrast to the vehicle lighting device 11 is the lens 14 the vehicle lighting device 31 not reflective designed. To illuminate the front 19 rather, an additional light source in the form of at least one light emitting diode 32 used. That of this at least one LED 32 radiated light L is on the front 19 the aperture 15 thrown and from there into the lens 14 reflected, in particular diffuse. In this way too, an additional area of the light emission pattern M can be produced, for example the upper area M2.

It is a generally viable variant that could still be taken as an embodiment with that the at least one light emitting diode 32 directly on the lens 14 shine. In this case, the aperture can 15 especially horizontally positioned and the light emitting diode (s) 21 and the reflector 13 be placed in the place where else the (in this case not existing) front of the panel 15 is arranged.

The vehicle lighting device 31 has the advantage that the areas M1 and M2 are independently adjustable with respect to their brightness. For example, such a brightness of the at least one light emitting diode 32 be generated range M2 to a brightness of the range M1 be equalized, in particular for generating at least one new light function.

In particular, if the light generating unit 12 and / or the at least one light-emitting diode 32 are dimmable, can thus provide a Lichtabstrahlmuster M with a reduced, substantially homogeneous brightness.

In addition, by the at least one light emitting diode 32 producible area M2, for example, by an orientation of the at least one light emitting diode 32 particularly variable formable. The at least one light-emitting diode can also be provided with a primary optics.

While the invention has been further illustrated and described in detail by the illustrated embodiment, the invention is not so limited and other variations can be derived therefrom by those skilled in the art without departing from the scope of the invention.

Thus, the convex surface of the lens may also be an ellipsoidal or paraboloidal surface. Generally, the lens is not limited to convex lenses but may be e.g. also concave or convex-concave lenses. A lens may generally be understood to mean an optical imaging element or imaging system, which may also comprise a lens in the narrower sense.

In general, the position and rotational position of the elements of the vehicle lighting device can vary from one another. So the light generating unit ( 12 ) or the light exit surface against the main plane H of the reflector 13 be angled or moved out of focus F1 out. Also like the aperture 15 against the lens 14 be twisted and / or moved.

In addition, the reflector may be angled relative to the lens. In particular, the main plane H of the reflector may be oblique to the optical axis of the lens. An associated inclination angle is preferably not more than about 20 °. As a result, color mixtures can be at least partially compensated, and monochrome color fringes are suppressed.

The shutter may also be selectively removable from the beam path and reinserted, e.g. tiltable or pivotable to be able to illuminate a larger area, e.g. in an off-road use of the electric bike.

Claims (13)

Lighting device ( 11 ; 31 ), comprising - one by means of at least one light source ( 12 ), in particular light-emitting diode, illuminable reflector ( 13 ), - a reflector ( 13 ) downstream lens ( 14 ) and - the reflector ( 13 ) and the lens ( 14 ) intermediate diaphragm ( 15 ), where - the diaphragm ( 15 ) a the reflector ( 13 ) facing back ( 18 . 18a ) and a reflector ( 13 ) facing away, at least partially reflective front ( 19 ), and - the lighting device ( 11 ; 31 ) arranged and arranged, the front side ( 19 ) the aperture ( 15 ) and from there light (L) into the lens ( 14 ) to reflect. Lighting device ( 11 ) according to claim 1, wherein the lens ( 14 ) at least one partially transparent mirrored area ( 17 ), on which of the reflector ( 13 ) emitted light (L) partly on the front side ( 19 ) the aperture ( 15 ) is reflectable. Lighting device ( 31 ) according to claim 1, wherein the lighting device ( 31 ) at least one additional light source ( 32 ) for lighting the front ( 19 ) the aperture ( 15 ) having. Lighting device ( 31 ) according to claim 3, wherein light (L) from the front ( 19 ) the aperture ( 15 ) only in one through the back ( 18 ; 18a ) the aperture ( 15 ) Shaded space is reflected. Lighting device ( 31 ) according to claim 3, wherein light (L) from the front ( 19 ) the aperture ( 15 ) in both through the back ( 18 ; 18a ) the aperture ( 15 ) shadowed space area as well as in a through the reflector ( 13 ) illuminated room area is reflected. Lighting device ( 31 ) according to claim 3, wherein the at least one light source ( 12 ; 32 ) for illuminating the reflector ( 13 ) is dimmable. Lighting device ( 11 ; 31 ) according to one of the preceding claims, wherein the front side ( 19 ) the aperture ( 15 ) is configured diffusely reflective. Lighting device ( 11 ; 31 ) according to one of the preceding claims, wherein the front side ( 19 ) the aperture ( 15 ) is occupied by at least one phosphor. Lighting device ( 11 ; 31 ) according to one of the preceding claims, wherein the reflector ( 13 ) has an at least approximately ellipsoidal basic shape. Lighting device ( 11 ; 31 ) according to one of the preceding claims, wherein the reflector ( 13 ) has a half-shell reflector and the aperture ( 15 ) a cut-off edge ( 10 ) on a main plane (H) of the reflector ( 13 ) having. Lighting device ( 11 ; 31 ) according to one of the preceding claims, wherein the lighting device ( 11 ; 31 ) is a vehicle lighting device, in particular headlights, is. Lighting device ( 11 ; 31 ) according to claim 11, wherein the vehicle lighting device comprises a lighting device ( 11 ; 31 ) for an electric bike. Method for operating a lighting device ( 11 ; 31 ), the method comprising at least: - illuminating a reflector ( 13 ) by means of at least one light source ( 12 ); Blocking a part of the reflector ( 13 ) radiated light (L) by means of a back ( 18 ; 18a ) an aperture ( 15 ); - Irradiating a lens ( 14 ) by means of another part of the reflector ( 13 ) radiated light (L); - Irradiating a reflective front ( 19 ) the aperture ( 15 ) with light (L) so that the light (L) thereof at least into one through the back ( 18 ; 18a ) the aperture ( 15 ) shadowed space area of the lens ( 14 ) falls.

Images