DE102014223933A1 - headlight module - Google Patents

Abstract

The invention relates to a headlamp module (100, 100 ') having a radiation source (10, 10') of a beam steering device (11, 11 '), and a phosphor (12, 12') applied to a carrier material (13, 13 '), wherein the luminescent material (12, 12 ') can be excited to emit light by means of an electromagnetic radiation emitted by the radiation source (10, 10'), wherein at least one optical reflector is arranged between the beam steering device (11, 11 ') and the luminescent material (12, 12') Element having first optical arrangement (16, 16 ') is arranged and wherein in the radiation direction (15, 15') behind the phosphor (12, 12 ') at least one optical element having second optical arrangement (17, 17') is arranged.

Description

The invention relates to a headlight module which has a radiation source, a beam steering device and a phosphor applied to a carrier material, wherein the phosphor can be excited to emit light by means of an electromagnetic radiation emitted by the radiation source.

State of the art

Headlight modules from the field of automotive technology allow the choice between several, well-defined light distributions, such as dipped beam, high beam and fog light. Increasingly, so-called adaptive headlamp systems are spreading, which expand the selection of light distributions and allow, for example, dynamic cornering light, highway, city and bad weather light. The selection of the light distributions can be made depending on the situation by a controller in the motor vehicle.

A further development in the field of vehicle lighting represent so-called active headlamp modules. These are not limited to predefined light distributions, but allow, similar to a projector, any light distribution in the space in front of the vehicle. This makes it possible, for example, to hide oncoming and preceding vehicles within the own high beam, also referred to as so-called glare-free high beam, or highlight possible sources of danger by direct lighting for the driver.

Such active headlamp modules can be realized essentially in two principal ways. In subtractive systems, the entire generated luminous flux is passed through a matrix of optically active elements, for example LCD, LCoS, DMD. Bright areas are created by allowing the luminous flux to pass through. For dark areas, the luminous flux is absorbed by means of the optically active elements, for example LCD or LCoS, or deflected, for example by means of DMD, in the direction of an absorber. In subtractive systems, the generation of light and its variable distribution in space take place in different components. For this reason, the power density of the light source does not limit the resolution of the system. Small-sized systems with relatively high resolutions can therefore be achieved. Due to the principle, the optical losses are higher in a subtractive system than in an additive system.

Additive systems illuminate the scene via matrix arrangements of light sources, for example LEDs, in which the individual light sources can be switched on and off as required. In an ideal additive system, therefore, the entire amount of light generated is always used. The necessary cooling of the light source matrix in such a system typically limits the size, the maximum brightness and / or the achievable resolution.

One way to spatially separate light generation and distribution in an additive active headlight module is to use a stimulable phosphor with electromagnetic radiation, for example laser radiation. The phosphor is scanned here with the stimulating radiation and then imaged using projection optics. Described is such a principle, for example in the DE 10 2010 028 949 A1 ,

However, the isotropic, d. H. evenly distributed in all directions, radiation of the phosphor for a strong loss of light intensity in the imaging of the phosphor in the far field. The locally generated light in the phosphor spreads in all directions in the phosphor and is finally diffused by scattering over a large part of the surface of the phosphor. A high spatial resolution of the brightness is difficult to achieve. The imaging of such a diffuse emitting phosphor by means of projection optics is possible only under optical losses, since a significant part of the emitted light can not be captured by the projection optics.

Disclosure of the invention

Against this background, a headlight module according to the independent claim 1 is presented with the present invention. Advantageous embodiments and advantageous developments of the invention are specified in the dependent claims.

The headlight module according to the invention is characterized in that a first optical arrangement having at least one optical element is arranged between the beam steering device and the phosphor and that a second optical arrangement having at least one optical element is arranged in the radiation direction behind the phosphor.

By means of an arrangement of a first optical arrangement in the radiation direction in front of the phosphor and a second optical arrangement in the radiation direction behind the phosphor, the emission angle of the phosphor can be selectively influenced such that the yield of the light emitted by the phosphor light can be increased. The first optical arrangement in the radiation direction in front of the phosphor and thus between the beam steering device and the phosphor enables the rays to impinge on the phosphor at a right angle regardless of the position of the beam steering device. In the case of a phosphor irradiated in this way, the second optical arrangement in the radiation direction behind the phosphor enables improved collimation, ie a guide in a straight line, of the light emanating from the phosphor. A diffuse radiation of the light from the phosphor can be prevented thereby.

The at least one optical element can be, for example, a converging lens, a reflective surface element, a microlens array or a holographic element. The convergent lens, also called collimator lens, convex lens or positive lens, is a spherical lens with positive refractive power. Rays incident on the convergent lens at different angles can be parallelized. A reflective surface element may be formed with or without a microstructure. A microlens array, also called a microlens array (MLA), is an array of multiple lenses that can be both rotationally symmetric and cylindrical. Adjacent lenses of a microlens array are arranged with as little or no gap as possible. A microlens array may be formed both convex and concave. Microlens arrays can be made of glass, plastic or silicone. The size of the individual lenses of a microlens array is preferably between a few microns to a few millimeters. Since the radiation source emits electromagnetic radiation, preferably in the form of laser light, in particular narrow-band laser light, which is directed onto the phosphor via the beam steering device, holographic elements (HOEs) can also be used as optical elements. For example, transmission holograms, which can replace lenses, or reflection holograms, which can replace mirrors, can be used. In order to achieve a high diffraction efficiency, the reflection holograms can preferably be used as phase holograms, in particular volume or surface holograms. A significant advantage of the use of holographic elements as optical elements are the integrable additional deflection functions, whereby the number of necessary optical elements of an optical arrangement can be reduced. Suitable materials for holographic elements are, for example, resists or photopolymers which are suitable for production processes, such as embossing or contact printing.

The first and / or the second optical arrangement can have exactly one such optical element or also two or more such optical elements, wherein with two or more optical elements in an optical arrangement, the optical elements of the same type can be formed or also optical elements of different types an optical arrangement can be arranged.

Particularly preferably, it can be provided that the first optical arrangement comprises a plurality of optical elements, wherein the plurality of optical elements may be a converging lens, a concave microlens array and a convex microlens array. The first optical arrangement then preferably has three different optical elements arranged one behind the other in the direction of radiation. In such an embodiment of the first optical arrangement, the converging lens arranged in the radiation direction as the first optical element serves to parallelize the beams arriving from the beam steering device from different angles. By a downstream convex microlens arrangement emitted by the converging lens beam can be focused and collimated by a concave microlens arrangement arranged behind it again. This arrangement corresponds to a reverse beam expander based on a Galilean telescope. With such a first optical arrangement, the rays impinging on the phosphor can be reduced in the beam diameter, with the isotropic radiations produced by the phosphor approximately corresponding to those of point sources. These point sources can be collimated again with the second optical arrangement arranged behind the phosphor in the radiation direction in order to be able to be imaged efficiently into the far field.

If the first optical arrangement or the second optical arrangement has both a convex microlens arrangement and a concave microlens arrangement as optical elements, then these may be formed together as one component, so that a combination of a convexly formed and a concave microlens arrangement in only one can be made as a component formed element. As a result, the number of components to be installed in the headlight module can be reduced, whereby the assembly cost can be reduced.

Furthermore, it is also possible that the first optical arrangement has a plurality of optical elements, wherein the plurality of optical elements may be a first holographic element and a second holographic element. The first arranged in the radiation direction holographic element can for deflecting and focusing of the output from the beam steering device Serve radiation. The second holographic element arranged in the radiation direction behind the first holographic element can serve to collimate the radiation emitted by the first holographic element.

The first holographic element and the second holographic element can be formed together as a component, wherein the first holographic element and the second holographic element can then be connected to one another via a carrier layer. The carrier layer, which is preferably transparent, may be in the form of glass, for example.

In order to be able to achieve a particularly good collimation of the radiation emitted by the phosphor and thus to be able to achieve a particularly efficient emission of the radiation into the far field, the second optical arrangement preferably has a microlens arrangement as the optical element. The microlens arrangement of the second optical arrangement is preferably convex.

In the direction of radiation behind the second optical arrangement, projection optics are preferably arranged. The radiation emitted by the luminescent substance or by the second optical arrangement arranged downstream of the luminescent material can be collected with the aid of the projection optics and imaged into the far field. The projection optics preferably has a plurality of collecting lenses arranged one behind the other.

The carrier material on which the phosphor is arranged is preferably transparent, so that the radiation emitted by the first optical arrangement can pass through the carrier material so that it can be introduced into the phosphor.

The phosphor is preferably not arranged directly on the carrier material, but a reflective layer may be arranged between the carrier material and the phosphor.

The headlight module according to the invention can preferably be used in the field of motor vehicle technology, in particular as part of an active driving light of a vehicle headlight. Other uses can be, for example, spotlights for stage lighting, workplace lighting, living room lighting, etc.

Further, measures improving the invention will be described in more detail below together with the description of preferred embodiments of the invention with reference to FIGS.

Show it:

1 a schematic representation of a headlamp module according to a first embodiment of the invention, and

2 a schematic representation of a headlamp module according to a second embodiment of the invention.

1 shows a possible embodiment of a headlight module 100 , The headlight module 100 has a radiation source 10 on, which is designed to emit electromagnetic radiation, for example laser light, in particular blue laser light. The electromagnetic radiation and in particular the path of the electromagnetic radiation is represented by the directional arrows. The radiation source 10 For example, may be a laser diode, wherein the radiation source 10 the radiation directed and bundled emits in the form of a laser light beam.

The radiation of the radiation source 10 meets a beam steering device 11 , The beam steering device 11 has a mirror device, for example a micromirror device. The beam steering device 11 can preferably be pivoted via an electrical control in two spatial axes. Thus, the on the beam steering device 11 incident laser light beam as a function of the electrical control of the Spiegelkkvorrichtung 11 be deflected in a desired direction. Instead of a single pivotable in two spatial axes beam steering device 11 You can also use two bumpers 11 can be used, which are pivotable in each one spatial direction.

The of the beam steering device 11 deflected electromagnetic radiation of the radiation source 10 meets a stimulable by electromagnetic radiation phosphor 12 which is on a carrier material 13 is arranged. The beam steering device 11 preferably has a drive that allows it from the radiation source 10 emitted radiation such means of the beam steering device 11 divert that time sequentially different areas of the phosphor 12 can be stimulated.

Similar to, for example, the line by line image construction in a picture tube of a television set, in which the human eye perceives a flat image by means of a suitable temporal and spatial control pattern, the control pattern of the beam steering device also becomes according to the invention 11 executed, allowing an interaction of temporal resolution of the human eye and reaction times of the phosphor 12 the human eye a steady lighting of the headlight module 100 without flicker or the like perceives.

As a result of excitation by means of electromagnetic radiation the phosphor gives 12 Light off. The phosphor 12 is formed for example of an optically active phosphor powder that is embedded in a suitable matrix material. The matrix material should be optically transparent in the relevant wavelength range, have a suitable refractive index and have sufficient thermal conductivity to dissipate the waste heat. Typical matrix materials are plastics, such as polymers and polycarbonates, glass, silicone or the like. The mixture of phosphor powder and matrix material may be in the form of a liquid, gel or paste prior to final curing and, in this form, directly or indirectly on the substrate, which may be transparent and in the form of sapphire, glass, plastic or the like be applied. Is the mixture of phosphor powder and matrix material indirectly on the substrate 13 Applied, is on the substrate 13 a reflective layer 14 arranged on which then the mixture or the phosphor 12 is arranged.

In order to achieve a high luminous efficacy by the emitted light is bundled, are in the radiation direction 15 in front of the phosphor 12 a first optics arrangement 16 and in the direction of radiation 15 behind the phosphor 12 a second optics arrangement 17 arranged.

The first optics arrangement 16 , which between the beam steering device 11 and the phosphor 12 is arranged, has three optical elements in the form of a converging lens 18 , a convex microlens array 19 and a concave microlens array 20 on. The of the beam steering device 11 deflected radiation first strikes the condenser lens 18 , in which the of the beam steering device 11 be initially parallelized from different angles incoming rays. The of the condenser lens 18 parallelized beams then hit the plano-convex microlens array 19 in which the rays are focused. The focused beams then hit the concave microlens array 20 where the rays are in turn collimated. This first optics arrangement 16 allows to reduce the beam diameter of the electromagnetic radiation, before this on the phosphor 12 impinges, so on the phosphor 12 Approximately point light sources can arise.

The outgoing of these point light sources, from the phosphor 12 emerging light then strikes the second optics assembly 17 , which as an optical element a plano-convex microlens array 21 through which that of the phosphor 12 emerging light is collimated.

The collimated light then hits one in the direction of radiation 15 behind the second optics arrangement 17 arranged projection optics 22 which, in the embodiment shown here, three converging lenses arranged one behind the other 23 having. By means of the projection optics 22 The collimated light can be imaged particularly effectively in the far field.

In 2 is another possible embodiment of a headlight module 100 ' shown. As well as in 1 shown headlight module 100 also has that in 2 shown headlight module 100 ' a radiation source 10 ' , a beam steering device 11 ' one on a substrate 13 ' and a reflective layer 14 ' arranged phosphor 12 ' , one in the direction of radiation 15 ' in front of the phosphor 12 ' arranged first optical arrangement 16 ' , one in the direction of radiation 15 ' behind the phosphor 12 ' arranged second optical arrangement 17 ' and one in the radiation direction 15 ' behind the second optics arrangement 17 ' arranged projection optics 22 ' , the three converging lenses 23 ' includes, on.

This in 2 shown headlight module 100 ' is different from the one in 1 shown headlight module 100 in the nature of the optical elements of the first optical arrangement 16 ' , In the 2 shown first optical arrangement 16 ' has a first holographic element 24 ' and one to the first holographic element 24 ' spaced second holographic element 25 ' on, with the two holographic elements 24 ' . 25 ' via a transparent carrier layer 26 ' , For example, in the form of glass, are interconnected. The first holographic element 24 ' serves for the deflection and focusing of the beam steering device 11 ' emitted radiation. The in radiation direction 15 ' behind the first holographic element 24 ' arranged second holographic element 25 ' serves to collimate the of the first holographic element 24 ' emitted radiation before it to the phosphor 12 ' is delivered. The second optics arrangement 17 ' has as well as the second optics arrangement 17 of in 1 shown headlight module 100 a plano-convexly formed microlens array 21 ' as an optical element through which that of the phosphor 12 ' escaping light is collimated before moving to the projection optics 22 ' meets and is imaged by this into the far field.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102010028949 A1 [0006]

Claims (10)

Headlight module ( 100 . 100 ' ), with a radiation source ( 10 . 10 ' ), a beam steering device ( 11 . 11 ' ), and one on a carrier material ( 13 . 13 ' ) applied phosphor ( 12 . 12 ' ), wherein the phosphor ( 12 . 12 ' ) by means of one of the radiation source ( 10 . 10 ' ) emitted electromagnetic radiation for light emission, characterized in that between the beam steering device ( 11 . 11 ' ) and the phosphor ( 12 . 12 ' ) has at least one optical element having first optical arrangement ( 16 . 16 ' ) is arranged and that in the radiation direction ( 15 . 15 ' ) behind the phosphor ( 12 . 12 ' ) has at least one optical element having second optical arrangement ( 17 . 17 ' ) is arranged. Headlight module ( 100 . 100 ' ) according to claim 1, characterized in that the at least one optical element is a convergent lens ( 18 ), a reflective surface element, a microlens array ( 19 . 20 . 21 . 21 ' ) or a holographic element ( 24 ' . 25 ' ). Headlight module ( 100 . 100 ' ) according to claim 1 or 2, characterized in that the first optical arrangement ( 16 . 16 ' ) has a plurality of optical elements, wherein the plurality of optical elements is a converging lens ( 18 ), a concave microlens array ( 19 ) and a convex microlens array ( 20 ) are. Headlight module ( 100 . 100 ' ) according to claim 3, characterized in that the concave microlens array ( 19 ) and the convex microlens array ( 20 ) are formed together as a component. Headlight module ( 100 . 100 ' ) according to claim 1 or 2, characterized in that the first optical arrangement ( 16 . 16 ' ) comprises a plurality of optical elements, wherein the plurality of optical elements comprises a first holographic element ( 24 ' ) and a second holographic ( 25 ' ) Element are. Headlight module ( 100 . 100 ' ) according to claim 5, characterized in that the first holographic element ( 24 ' ) and the second holographic element ( 25 ' ) are formed together as a component, wherein the first holographic element ( 24 ' ) and the second holographic element ( 25 ' ) via a carrier layer ( 26 ' ) are interconnected. Headlight module ( 100 . 100 ' ) according to one of claims 1 to 6, characterized in that the second optical arrangement ( 17 . 17 ' ) as an optical element a microlens array ( 21 . 21 ' ) having. Headlight module ( 100 . 100 ' ) according to claim 7, characterized in that the microlens array ( 21 . 21 ' ) of the second optical arrangement ( 17 . 17 ' ) is convex. Headlight module ( 100 . 100 ' ) according to one of claims 1 to 8, characterized in that in the radiation direction ( 15 . 15 ' ) behind the second optical arrangement ( 17 . 17 ' ) a projection optics ( 22 . 22 ' ) is arranged. Headlight module ( 100 . 100 ' ) according to one of claims 1 to 9, characterized in that the carrier material ( 13 . 13 ' ) is transparent.

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