DE102011003300A1 - lighting device - Google Patents

Abstract

The lighting device (1) has a plurality of light sources (3) arranged at a distance from one another, a reflector (4) for reflecting at least some of the light (B1, B2, B3) emitted by the light sources (3) and light mixing optics (8) for spatial mixing of light (B1, B2, B3) emitted into a penumbra region (HS) of the lighting device (1), the light mixing optics (8) being transparent optics, the surface (9) of which has at least one light deflecting structure (10, 12a, 12b, 13 ), which is designed to deflect light (B1, B2, B3) incident on it at least partially anisotropically.

Description

The invention relates to a lighting device comprising a plurality of light sources arranged at a distance from each other, a reflector for reflecting at least part of the light emitted by the light sources, and a light mixing optics for the spatial mixing of light emitted into a partial shade region of the light device.

LED lighting devices that work with multiple light emitting diodes (LEDs) of different colors, in their operation with reflectors color rings in the penumbra area of the reflector. This also applies to LED lighting devices with multiple LEDs that show in operation with reflectors light / dark rings o. Ä. In the penumbra area of the reflector.

For the purpose of color or brightness homogenization of the light emitted into the penumbral area of the reflector, diffusers (for example made of frosted glass) have hitherto been used, which scatter the light incident on them isotropically. These have the disadvantage that an efficiency of the lighting device is significantly reduced.

It is the object of the present invention to provide a lighting device equipped with a plurality of light sources and a reflector connected downstream thereof which can reduce brightness and / or color fluctuations in a partial shade of the reflector with an increased efficiency.

The object is achieved by a lighting device comprising a plurality of light sources arranged at a distance from one another, a reflector for reflecting at least part of the light emitted by the light sources, and a light mixing optics for spatially mixing at least light emitted into a semi-shade or penumbral region of the lighting device. The light mixing optics is a substantially transparent optic, the surface of which has at least one light deflection structure which is designed to deflect light incident on it at least partially anisotropically.

By using a transparent optic, the efficiency of the light emission is considerably improved, in contrast to a diffuser. The homogenization of the light pattern in the partial shade (area) of the reflector is achieved by the deflection of the light at the Lichtablenkstruktur at different angles, due to which light of the respective light sources is more strongly superimposed on the light of the other light sources and thus brightness and / or color contrasts are reduced ,

The fact that the light deflecting structure is designed to at least partially anisotropically deflect light impinging on it also includes, in particular, that a portion of the light impinging on it can be transmitted without significant angular deflection. In other words, an (extended) light beam incident on the light deflecting structure may exit the light deflecting structure at at least one defined deflection angle with respect to the direction of the incident light beam. The light deflecting structure can deflect incident light (particularly also with respect to one of the light sources) at one or more deflection angles. A (extended) light beam can consequently be split and / or widened by the light deflection structure, in particular also into at least two divergent partial beam bundles.

The reflector is preferably a shell-shaped reflector with a reflective inner side.

It is an embodiment that the light impinging on the light mixing optics is deflected by the light deflecting structure by no more than 10 °, in particular not more than 5 ° (small-angle deflection). This deflection angle has been found to be sufficient to effectively suppress a ring formation o. Ä. In the partial shade of the reflector due to a different with respect to the reflector edge beam angle of the spaced light sources of the same magnitude. In addition, such deflection angle can be achieved with low production costs for the Lichtablenkstruktur.

The light mixing optics may consist in particular of glass or plastic.

It is still an embodiment that the light mixing optics essentially has a shape of a spherical cap. This causes a particularly good Lichtabstrahleffizienz, as the back-flared light from the dome largely directed back to the target area. Such a spherical cap light mixing optics is particularly advantageous for use in a positioning between the light sources and the reflector. The spherical cap light mixing optics can be used in particular as a hood or cover, which vaulted the light sources.

It is yet another embodiment that the light mixing optics essentially has a shape of a disk. The disc-shaped Lichtmischoptik can be placed in particular without a significant increase in size on an edge of the reflector and is very easy to install, possibly even subsequently.

The light deflection structure may be present on at least one side of the light mixing optics, for. B. on a side facing the light sources inside and / or on a side facing away from the light sources outside.

It is also an embodiment that the light mixing optics has raised areas or projections whose flanks are angled locally relative to a basic shape of the light mixing optics. The basic form can z. B. be a dome shape or disc shape and gives particular the shape of the light mixing optics without taking into account the Lichtablenkstruktur at least approximately again. The flanks make it possible in a simple manner to anisotropically deflect a light beam impinging on it into a respective spatial area determined by the angle of inclination of the flanks.

The flanks may be inclined in particular in opposite directions by a same inclination angle. However, the flanks may also have different angles of inclination, lengths and / or shapes.

It is still an embodiment that the edges are locally up to 20 °, in particular up to 8 °, angled. As a result, in particular when optical glass is used as a material of the light mixing optics, a deflection angle of up to 10 °, in particular of up to 5 °, can be achieved.

It is also an embodiment that the flanks are configured in a straight line profile. This facilitates production of the light mixing optics. Alternatively, however, the flanks may also be curved, have a shape of a polyline consisting of at least two sections, or have a free form.

It is still an embodiment that adjacent raised areas are spaced from each other by a respective base area. A basic area can be understood in particular to be the area between two raised areas whose surface corresponds in particular substantially to the basic shape (that is to say that the at least one basic area is formed (locally) conforming to the basic shape of the light mixing optics). Light that strikes the base area is essentially not deflected in its direction. Thus, a part of the original spray pattern can be retained, which further supports homogenization.

It is also an embodiment that the flanks of the raised areas a respective. Limit roof area, wherein the at least one roof area is formed in particular locally substantially conforming to the basic shape of the light mixing optics. Even so, a part of the original spray pattern can be maintained, which further supports homogenization.

In particular, in the event that the light mixing optics substantially has a shape of a spherical cap and the Lichtmischoptik raised areas whose edges are angled relative to a basic shape of the Lichtmischoptik, it is a particularly efficient embodiment of the Lichtmischoptik that the raised areas rotationally symmetric, in particular annular , are designed to an axis of symmetry of the light mixing optics and the flanks are meridional angled.

It is also an embodiment that the light sources, the reflector and the light mixing optics are each rotationally symmetrical to a longitudinal axis of the lighting device. Consequently, the longitudinal axis also represents an axis of symmetry for these elements. Thus ring formation or the like can be suppressed in a comparatively simple manner.

It is a particularly effective embodiment, which is preferred for avoiding light losses, that the light mixing optics is connected between the light sources and the reflector.

It is an additional or alternative embodiment that the light mixing optics is connected behind the reflector. The light mixing optics of this embodiment is particularly easy to install.

It is still an embodiment that the light sources are semiconductor light sources, in particular light-emitting diodes. The semiconductor light sources can shine in the same color or in different colors. A color can. monochrome (eg, red, green, blue, etc.) or multichrome (eg, white). The light emitted by the at least one semiconductor light source may also be an infrared light (IR LED) or an ultraviolet light (UV LED). Multiple semiconductor light sources can produce a mixed light; z. B. a white mixed light. The at least one semiconductor light source may contain at least one wavelength-converting phosphor (conversion LED). The phosphor can alternatively or additionally be arranged remotely from the light-emitting diode ("remote phosphor"). The at least one semiconductor light source may be in the form of at least one individually housed semiconductor light source or in the form of at least one chip. Several chips can be mounted on a common substrate ("submount"). The at least one semiconductor light source may be equipped with at least one own and / or common optics for beam guidance, z. At least one Fresnel lens, collimator, and so on. Instead of or in addition to inorganic light emitting diodes, z. Based on InGaN or AlInGaP, are generally also organic LEDs (OLEDs, eg polymer OLEDs) can be used. Alternatively, the at least one semiconductor light source z. B. have at least one diode laser.

It is a general design, even for non-semiconductor light sources, that the light sources are light sources of different colors or emit light of different colors (eg, peak wavelength, bandwidth, etc.).

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

In the following figures, the invention will be described schematically with reference to an embodiment schematically. In this case, the same or equivalent elements may be provided with the same reference numerals for clarity.

1 shows a sectional view in an oblique view of a lighting device according to the invention;

2 shows the lighting device as a sectional view in side view;

3 shows a sectional view in an oblique view enlarged on a plurality of light-emitting diodes mounted light mixing optics of the lighting device; and

4 shows a sectional view in side view of a section of the Lichtmischoptik.

1 shows an oblique view of a lighting device 1 from which along a longitudinal axis L a pie-shaped piece is cut out.

The lighting device 1 has a pedestal 2 on, at its aligned in the direction of the longitudinal axis L surface is a plurality of semiconductor light sources in the form of light-emitting diodes 3 are located. The light-emitting diodes 3 are arranged in a plane perpendicular to the longitudinal axis L in a 5 × 5 matrix form, the corner places not with light emitting diodes 3 are occupied. As a result, a circular shape at least roughly approximated arrangement of the LEDs 3 reached. The light emitting surfaces of the LEDs 3 are therefore spaced apart in the plane, z. B. with a (pitch) distance of 3 mm to 4 mm.

The light-emitting diodes 3 is a cup-shaped reflector 4 optically downstream. The light-emitting diodes 3 are at a rear opening 5 of the reflector 4 arranged and radiate their light partly directly and partially indirectly through a reflection on a reflective inside 6 of the reflector 4 through a light exit plane E of the reflector 4 from.

The light exit plane E corresponds to one through a front edge 7 of the reflector 4 spanned level. A radius of the front edge 7 For example, can be about 50 mm at a distance to the light emitting diodes 3 of 65 mm.

A profile shape of the reflector 4 may for example be parabolic or hyperbolic. The inside 6 of the reflector 4 can have facets. The light-emitting diodes 3 can emit light of the same color or different color.

The lighting device 1 also has a light mixing optics 8th of a substantially transparent material (eg, plastic or glass) that is optically interposed between the light emitting diodes 3 and the reflector 4 is switched. For this purpose, the light mixing optics 8th essentially the shape of a spherical cap, which the light-emitting diodes 3 vaulted and on the pedestal 2 seated.

The light-emitting diodes 3 , the reflector 4 and the light mixing optics 8th each rotationally symmetrical to the longitudinal axis L of the lighting device.

2 shows the lighting device 1 as a sectional view in side view. The perpendicular to the longitudinal axis L spatially distributed light-emitting diodes 3 emit a light cone emerging from the light entry plane E, whose lateral surface is in profile by a light beam B1, B2 or B3 between the respective light-emitting diode 3 and the front edge 7 of the reflector 4 is defined. This light beam B1, B2, B3 is here dashed lines for three different light-emitting diodes 3 located. Behind the reflector 4 In a region, a partial shade HS is formed, in which only light of a part of the light emitting diodes 3 falls. In the partial shade HS is formed by the spatially alternately visible light-emitting diodes 3 a brightness or color pattern, here typically in the form of rings or ring segments concentric with the longitudinal axis L. These rings or ring segments are also based on the fact that the light of the LEDs 3 at a different angle of radiation (eg with respect to the longitudinal axis L) in the half-shadows HS falls. An angular difference α of two adjacent lines B1, B2 is for example between 2 ° and 3 °, z. B. about 2.5 °.

The light mixing optics 8th serves to at least the falling in the light shades HS beams of light, z. B. B1, B2 and B3, divert such anisotropic and thus spatially reinforced to mix that uniformed in the penumbra HS light radiation is homogenized.

3 shows as a sectional view in an oblique view enlarged on the light emitting diodes 3 patch and this vaulting spherical cap light mixing optics 8th ,

The light mixing optics 8th has on its surface, namely at the light emitting diodes 3 opposite outside 9 , a Lichtablenkstruktur in the form of several concentrically arranged around the longitudinal axis L, annular raised areas 10 or protrusions. Thus, the half-shade HS can be homogenized in all circumferential directions with respect to the longitudinal axis L.

The sublime areas 10 are essentially over the entire outside 9 distributed, but the sublime areas 10 alternatively also only at one edge region of the light mixing optics 8th be present etc.

4 shows a section in side view (ie, in the profile in a section through the longitudinal axis L) a section of the light mixing optics 8th , The light mixing optics 8th is bowl-shaped with a smooth inside 11 and with the sublime areas 10 on its outside 9 , The basic form of the light mixing optics 8th in profile is therefore a circular or circular segmental basic shape. The inside 11 has such a circular basic shape or is z. B. substantially approximated by corresponding (linear) polylines of the circular basic shape.

The sublime areas 10 jump in the radial direction (with respect to a polar coordinate system, which originates in the intersection of the longitudinal axis L with that through the free edge of the Lichtmischoptik 8th spanned plane has) and each have two mutually oppositely oriented, rectilinear edges 12a . 12b on. The flanks 12a . 12b are local to the circular basic shape (ie near these flanks 12a . 12b ) an angle of inclination β = approx. + 8 ° or approx. -8 °. The flanks 12a . 12b are therefore meridionally angled by an angle of about 8 °.

The flanks 12a . 12b the same sublime area 10 limit a roof area 13 which has locally substantially the same basic shape as the Lichtmischoptik 8th (ie that they conform locally to the basic shape of the Lichtmischoptik 8th are). The roof area 13 may thus have a profile-segment-shaped shape (including orientation) or a straight shape (including orientation) in accordance with the locally underlying portion of the inside 11 the light mixing optics 8th exhibit. The flanks 12a . 12b adjacent raised areas 10 are by a respective basic area 14 spaced apart. The basic areas 14 also have locally substantially the same basic shape as the Lichtmischoptik 8th , They also have substantially the same length as the roof areas 13 ,

An exemplary drawn, extended light beam B2, which at a raised area 10 on the inside 11 the light mixing optics 8th will meet where he is on the outside on a roof area 13 or a basic area 14 exit, have substantially the same direction or beam angle as in its impact on the inside 11 , However, the light beam B2 occurs on one of the flanks 12a or 12b from there, it is deflected anisotropically there with a predetermined angular deflection γ, namely in the direction of an outwardly directed surface normal. The size of the angular deflection γ is generally smaller than the inclination angle β, so that, for example, the inclination angle β of magnitude amounts to approximately 5 °, an angular deflection γ of about 2.5 °. This angular deflection γ is preferably similar to the angular difference α of the light beams of two adjacent light-emitting diodes 3 , z. B. B1, B2, at the front edge 7 of the reflector 4 , The incident light beam B2 is thus anisotropically radiated at three different angles (with an angular deflection γ to the incident light beam B2 of -2.5 °, 0 ° and + 2.5 °, respectively). In other words, the (extended) incident light beam B2 is divided into three divergent partial beams. That with the magnitude angular deflection | γ | > 0 radiated light is deflected in particular in the half-hard HS on areas which receive a brightness and / or color balance by the additional (deflected) light of the light beam B2, which brightness and / or color contrasts of the overall image is reduced. The original beam pattern of a light source (which without the Lichtmischoptik 8th is generated) is weakened. It is particularly preferred if the angle-deflected light or light component of a light source is predominantly deflected into an area irradiated by an adjacent light source.

Of course, the present invention is not limited to the embodiment shown.

Thus, other light sources can be used as light emitting diodes or other semiconductor light sources, eg. As light bulbs, fluorescent tubes, gas discharge lamps, etc.

Furthermore, the flanks of a raised area may also have different angles of inclination.

The raised area may also dispense with a roof area and z. B. have a triangular shape.

Adjacent raised areas may also abut each other directly so that they are not separated by a base area.

The flanks may also be curved.

The presence of the raised areas is analogously and functionally equivalent to the presence of complementarily shaped recessed areas or recesses (for example, where the roof areas described correspond to basic areas and the basic areas described correspond to roof areas of the recesses, etc.).

The profile of the light deflection structure may, for example, have an at least substantially sinusoidal surface. Thus, a substantially continuous beam expansion can be achieved.

LIST OF REFERENCE NUMBERS

1

lighting device

2

base

3

led

4

reflector

5

Rear opening of the reflector

6

Inside of the reflector

7

front edge

8th

Light mixing optics

9

Outside of the light mixing optics

10

raised area

11

Inside of the light mixing optics

12a

Flank of the raised area

12b

Flank of the raised area

13

roof

14

basic area

B1

beam of light

B2

beam of light

B3

beam of light

L

longitudinal axis

α

Angle difference of light rays at the front edge of the reflector

β

Inclination angle of a flank

γ

Angular deflection by a flank

Claims (14)

Lighting device ( 1 ), comprising - a plurality of spaced-apart light sources ( 3 ), - a reflector ( 4 ) for reflecting at least part of the light source (s) ( 3 ) radiated light (B1, B2, B3) and - a Lichtmischoptik ( 8th ) for spatial mixing of at least in a partial shade area (HS) of the lighting device ( 1 ) radiated light (B1, B2, B3), - wherein the light mixing optics ( 8th ) is a transparent optic whose surface ( 9 ) at least one Lichtablenkstruktur ( 10 . 12a . 12b . 13 ), which is configured to at least partially anisotropically deflect light (B1, B2, B3) impinging on it. Lighting device ( 1 ) according to claim 1, wherein the light mixing optics ( 8th ) incident light (B1, B2, B3) is deflected by not more than 10 °. Lighting device ( 1 ) according to one of the preceding claims, wherein the light mixing optics ( 8th ) has substantially a shape of a spherical cap. Lighting device according to one of claims 1 or 2, wherein the light mixing optics substantially has a shape of a disc. Lighting device ( 1 ) according to one of the preceding claims, wherein the light mixing optics ( 8th ) has raised areas ( 10 . 12a . 12b . 13 ) whose flanks ( 12a . 12b ) locally compared to a basic form of the Lichtmischoptik ( 8th ) are angled. Lighting device ( 1 ) according to claim 5, wherein the flanks ( 12a . 12b ) are locally angled up to 20 °. Lighting device ( 1 ) one of claims 5 or 6, wherein the flanks ( 12a . 12b ) are designed in a straight line in profile. Lighting device ( 1 ) according to one of the claims. 5 to 7, with adjacent raised areas ( 10 . 12a . 12b . 13 ) by a respective basic area ( 14 ) are spaced apart from each other and the flanks ( 12a . 12b ) of the raised areas ( 10 . 12a . 12b . 13 ) a respective roof area ( 13 ), the at least one basic area ( 14 ) and the at least one roof area ( 13 ) locally conforming to the basic form of the Lichtmischoptik ( 8th ) are formed. Lighting device ( 1 ) according to claim 3 and any one of claims 5 to 8, wherein the raised areas ( 10 ) rotationally symmetrical, in particular annular, to an axis of symmetry (L) of the light mixing optics ( 8th ) and the flanks ( 12a . 12b ) are meridionally angled. Lighting device ( 1 ) according to one of the preceding claims, wherein the light sources ( 3 ), the reflector ( 4 ) and the light mixing optics ( 8th ) each rotationally symmetrical to a longitudinal axis (L) of the lighting device ( 8th ) are. Lighting device ( 1 ) according to one of the preceding claims, wherein the light mixing optics ( 8th ) between the light sources ( 3 ) and the reflector ( 4 ) is switched. Lighting device according to one of claims 1 to 10, wherein the light mixing optics is connected behind the reflector. Lighting device ( 1 ) according to one of the preceding claims, wherein the light sources are semiconductor light sources, in particular light-emitting diodes ( 3 ), are. Lighting device ( 1 ) according to one of the preceding claims, wherein the light sources ( 3 ) Emit light of different colors.

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