DE102016116446B4 - Appliances Light - Google Patents

Abstract

Household appliance lamp (10) for cooking appliances, such as ovens, microwave ovens or steamer,
with an LED (13) as the light source,
with a luminaire housing (14) provided for arrangement on a device wall,
- With a light exit opening (17) in the lamp housing (14) which is closed by a translucent cover (21),
- With a spacer element which is arranged between the LED (13) and the light exit opening (17) and in front of the light exit plane of the LED (13) sits,
- With a reflecting means which the light emitted from the LED (13) light of the cover (21), characterized in that
- The spacer element is a uniform material light guide (15) which receives the light from the LED and bundles,
- The entire light exit surface (17) of the light guide (15) relative to a central axis (LA) of the light guide (15) is provided with a uniform inclination and so the cone axis (K) of the light exit surface (17) emerging light cone also relative to the central axis (LA) of the light guide (15) is inclined
- The reflection means is a reflector ((20) which spans a reflector space (29),
- The light guide (15) is guided into the reflector space (29),
- The reflector (20) substantially from the light guide (15) emerging scattered radiation (S) in the direction of cover (21) directs.

Description

The invention relates to a household appliance lamp, in particular light for cooking appliances, such as ovens, microwave ovens or steamer, with an LED as a light source, with a provided for installation on a device wall luminaire housing, with a light exit opening in the luminaire housing, which is closed by a translucent cover, with a Spacer element, which is arranged between the LED and the light exit opening and located in front of the light exit plane of the LED, with a reflection means, which forward the light emitted by the LED light of the cover.

Domestic appliance lights are known from the prior art in many forms. They are usually used to illuminate the interior of a household appliance during its operation or the insight of a user in such a recording room.

Whether it concerns home appliances for food storage (eg refrigerators) or home appliances for cooking food (eg ovens), certain requirements are made that are often difficult to reconcile. In principle, the illumination of the household appliance interior should allow a sufficient visual perception of the food by the user, which often causes problems due to shadowing, for example by shelves in refrigerators or trays in ovens due to shading. In addition, the lighting should basically not dazzle the user as possible, with the technical components used for this purpose bring light losses, which are disadvantageous.

The use of LEDs as light sources has led to new possibilities in the lighting of household appliances, while at the same time presenting the designers with new challenges.

In particular, in cooking appliances for food, such as ovens or steamer, great constructive efforts must be made to prevent overheating of the LEDs and a concomitant damage. For this purpose, not only the LED's own heat must be dissipated effectively. In addition, measures must be taken to minimize the temperature stresses on the LED caused by the cooking process.

The DE 10 2009 002 775 A1 should serve as an example of a cooking appliance lamp from the prior art. In per se usual way, this lamp is held in a housing cutout on a light housing. The light exit opening of the lamp housing is provided with a translucent cover, which protects the lamp interior primarily from contamination, but also already represents a first thermal barrier. The luminaire housing carries at its end facing away from the Gargeräteraum a cylindrical spacer element, wherein the cylinder jacket surface is surrounded by a reflection material. The cylinder cover surfaces are provided with translucent cover elements. On the one hand, this cylinder designed in this way serves to space the LED arranged at its end remote from the cooking chamber as far as possible from the cooking chamber and to minimize the heat load by means of this first measure. In addition, the cover elements form further temperature barriers. The cylinder itself also serves as a light well to guide the light emitted by the LED towards the cooking chamber. Finally, as a further measure, the LED is mounted on a heat sink, so that the operating heat but also on the heat barriers to the LED reaching residual heat can be dissipated.

It is also known from the prior art document which can not be assigned by hand to provide the cavity existing between the LED and the light exit opening of the inner wall of the cooking chamber with a light-permeable insulating material. Thus, the heat radiation originating from the cooking chamber is minimized and the illumination of the interior space is made possible.

In the prior art, the measures described here for spacing the LED from the cooking chamber and for heat shielding reduce the luminous efficiency and the illumination quality of the domestic appliance interior. In order to compensate for the diminished light yield, more powerful LEDs can be used, whereby their higher operating temperature is problematic.

WO2009 / 141068 A1 or EP 1598682 A2 use light guides to direct the light away from a cooking area in the oven into it. However, the highly directed radiation caused by this requires a large number of light exit openings and - depending on the technical implementation - a variety of light sources and light guides. In addition, the large number of point sources of light in the inner wall of the housing with its very high brightness is perceived as unpleasant, so that such solutions are reluctantly implemented for cost and comfort reasons.

Finally, for optimum illumination of the household appliance interior, especially in cooking appliances, several lights are arranged in the device side walls between the planes provided for supporting elements. Thus, each support element level in ovens, for example, each provided for a baking tray level one Assigned lighting so shading by other support elements do not affect the illumination quality of each level.

Due to standardized external dimensions and the aim of keeping the usable interior of the cooking appliance as large as possible, the space available behind the lateral inner walls are extremely limited. This complicates the design of home appliance lighting for cooking appliances using LEDs, since the temperature protection serving distance between the oven and LED is limited.

In this respect, in particular when positioning a domestic appliance light behind the side wall of a cooking chamber, the light losses due to design in the prior art can not be readily compensated for by more powerful LEDs, since these generally produce a much higher operating heat.

From the JP 2011-126262 A is a so-called retrofit lamp known, which uses an LED radiation source, but can be used with conventional socket in commercial versions. In addition to the basic structure of such a lamp, this document discloses various ways to scatter the more directed light of the LED radiation source. For this purpose, on the one hand, the use of several LEDs excited in a lamp, which are to be mounted in different orientations. On the other hand, this document proposes as an alternative the use of scattering coatings or scattering, arranged in front of the LED optics. A use in cooking appliances is not suggested in the document itself.

Also JP 2012-089256 A discloses a retrofit lamp, in which also ways of light distribution of LED radiation sources are disclosed. A point-like illumination is achieved by specially shaped, rod-shaped light guides, an additional, diffused light effect is obtained by a dome-shaped, the rod-shaped light guide surrounding the second light guide. Also in this document use for cooking appliances is not addressed.

A luminaire for room and building illumination revealed EP 2 864 694 B1 , There, an elongated luminaire with an LED radiation source is proposed, which has a light scattering optics and uses a channel-like reflector for light distribution.

Due to their design, retrofit lamps and luminaires for room and building lighting are also unsuitable for use in highly thermally stressed environments because of the lack of effective heat dissipation. Moreover, due to their size, they can not be used in the standardized housing dimensions of cooking appliances without the need for elaborate special adjustments to the detriment of cooking appliance use.

Out DE 10 2014 102 355 A1 a car light is known, which arranges a diffusion element between the light source and the reflector to forward the reflector scattered light.

US 2005/0207177 A1 shows a street lamp, in which the light source is arranged at the ground level and is first fed via bundles a reflector, which then provides a light distribution.

The various possibilities of diffused light distribution through optics and reflectors is the focus of attention WO 2014/120 245 A1 ,

In view of the generic state of the art of the cooking appliance lights, it is an object of the invention to provide a compact home appliance light, in particular for cooking appliances, whose effectively usable for the interior lighting light output is maximized.

The object of the invention is achieved by a domestic appliance luminaire with the features of claim 1, in particular with its characterizing features, according to which the spacer element is initially a material-uniform light guide which receives and concentrates the light of the LED and after which the reflection means is a reflector which spans a reflector space, that the light guide is guided into the reflector space.

The main advantage of this feature group of the main claim for the household appliance lamp according to the invention is the fact that two different light-influencing components are used to maximize the light output. By means of the material-uniform light guide, such as a plastic or glass Lichtleitstabes, ie an existing fiber light guide, the light of the LED is recorded, bundled and brought with the lowest possible stray losses close to the light exit opening of the lamp housing, so close to the inner wall of the domestic appliance interior. In this case, the optical waveguide is at least partially in the reflector space, so that the scattered radiation emerging from the optical waveguide is received and also directed in the direction of the light exit opening of the luminaire housing, ie in the direction of the domestic appliance interior. At the same time, the light guide allows the widest possible spacing of the LED from the household appliance interior and serves for heat shielding. Also, the heat shield is the reflector, which not only the scattered light, but also reflected from the device interior entering heat radiation.

In order to produce a glare-free illumination of the device interior is provided according to another group of features of the main claim that the entire light exit surface of the light guide is provided relative to a central axis of the light guide with a uniform inclination and so the cone axis of emerging from the light exit surface light cone also relative to the central axis of the Light guide is inclined, wherein in the application, the light exit surface facing away from the user, that is inclined in the direction of, for example, the cooking chamber rear wall. Due to the inclined light exit surface of the emerging light cone is pivoted into the device interior, which is expressed by a corresponding inclination of the cone axis - which rises from the cone tip and extends through the center of the cone bottom - expresses. The conical surface of the emerging light cone is determined by the emission angle (equal to the half-value angle) of the light exit surface.

The reflector is used according to the last feature group of the main claim essentially to capture the otherwise applicable as loss radiation, not in the domestic appliance interior incoming stray light, which inevitably emerges from the lateral surface of the light guide.

It is furthermore provided that the reflector directs the scattered light largely predominantly in the direction of the cone axis of the light cone emerging from the light exit surface of the light guide, so that a dazzling effect of the user caused by the reflected scattered light is largely avoided.

It is envisaged that the reflector has two web-shaped reflecting surfaces which emerge from a vertex axis, wherein the vertex axis is arranged near a light entry surface of the optical waveguide. This arrangement near the light entry surface of the light guide ensures that the scattered light emerging from the light guide in principle is absorbed by the reflector.

In particular, it is provided that the first, sheet-shaped reflection surface is curved about an axis of curvature parallel to the apex axis, wherein it can be provided that the area near the light entrance surface lies below a plane in which the marginal rays of the beam cone defined by the emission angle of the LED on the boundary surfaces of the light guide shell to meet.

This ensures that a maximum of scattered light is collected and reflected towards the home appliance interior.

It is further provided that the light guide is offset laterally to the apex axis of the reflection surfaces, wherein it can additionally be provided that the inclined light exit surface of the light guide drops in the direction of the lateral offset. It is furthermore provided that the second sheet-shaped reflection surface is non-curved, in particular flat, and guided to the light entry area near the light entry surface and the light guide surface, wherein the inclination of the second reflection surface with respect to the cone axis of the emerging from the light exit surface light cone substantially to the inefficiency of the second reflection surface leads.

The offset of the light guide to the apex axis, in particular an offset from the first reflection surface away causes a stronger scattered light output by the first reflection surface. In the above-mentioned corresponding inclination of the light exit surface emerging from the light exit surface direct light as well as the reflected back from the reflector scattered light is guided in approximately the same direction in the domestic appliance interior.

It is further provided that the second sheet-like reflection surface is not curved and is guided to the light entry surface near transition region of the light exit surface and light guide surface, wherein the inclination of the second reflection surface with respect to the cone axis of the light exit surface emerging light cone essentially leads to the inefficiency of the second reflection surface.

In this way, with appropriate mounting position of the lamp ensures that the light is guided exclusively substantially in the direction of the appliance appliance rear wall, in particular the cooking chamber rear wall of a cooking appliance.

It is further provided that the reflector and the immersion depth of the light guide are matched to one another in the reflector space such that the reflector reflects only the scattered radiation emerging from the light guide, but not direct radiation emerging from the light exit surface.

• 1 die Explosionsansicht einer erfindungsgemäßen Leuchte,
• 2 eine Schnittansicht der Leuchte gemäß 1,
• 3 eine schematische Darstellung der Abstrahlcharakteristik der Leuchte gemäß 1 ohne den erfindungsgemäßen Reflektor an Hand einer Schnittdarstellung,
• 4 eine schematische Darstellung der Abstrahlcharakteristik der Leuchte gemäß 1 unter Berücksichtigung des erfindungsgemäßen Reflektors.

Further advantages as well as a better understanding of the invention follow from the description of an embodiment. Show it:

• 1 the exploded view of a lamp according to the invention,
• 2 a sectional view of the lamp according to 1 .
• 3 a schematic representation of the radiation characteristic of the lamp according to 1 without the reflector according to the invention with reference to a sectional view,
• 4 a schematic representation of the radiation characteristic of the lamp according to 1 taking into account the reflector according to the invention.

In the figures, a home appliance light, also called just light, total with the reference numeral 10 Provided. The home appliance light includes, as out 1 can be seen, first a heat sink 11 on which a circuit board 12 with attached LED 13 ( 2 ) is placed.

On the heat sink is still a light housing 14 of an electrically and thermally insulating material, such as plastic or ceramic, arranged within which a light guide 15 is held. In the present embodiment, it is a rod-shaped optical fiber made of glass. This has a LED near light entrance surface 16 ( 2 ) and a LED-distant light exit surface 17 , The light exit surface 17 is with respect to a center axis of the light guide 15 inclined. In terms of the board 12 she points one down, to the board 12 pointing inclination. Incidentally, the light exit surface is kept flat.

The luminaire housing 14 has recesses 18 , by means of which a detent spring 19 having reflector 20 on the luminaire housing 14 can be anchored. The reflector 20 in turn, forms an unspecified light exit opening of the lamp 10 , which through a translucent cover 21 , In the embodiment, a glass 22 , is closed. Finally, the reflector has 20 via locking elements R with which it is defined in a section of a device wall.

In addition to the light in the exemplary embodiment connection lead 23 , With their first ends in a manner not shown conductor tracks of the board 12 contact and theirs the board 12 opposite ends of a connector 24 for connection to the power supply.

2 shows the in 1 illustrated light 10 in a sectional view. This sectional view can be seen that the reflector 20 a first reflection surface 25 and a second reflection surface 26 formed. These reflection surfaces 25 / 26 form, together with the reflector side walls 27 the reflector space 29 and spring from a common vertex axis 28 , The reflection surfaces 25 / 26 are web-shaped, with the first reflection surface 25 is curved about a curvature axis (not shown). The axis of curvature of the first reflection surface 25 lies parallel to the vertex axis 28 , The second reflection surface 26 forms one, the apex axis 28 springing inclined surface. The apex axis 28 lies on the lamp center axis LM extending through the center of the luminaire housing floor surface and through the center of the cover element 21 extends.

The light guide 15 extends into the reflector space 29 in and is with its longitudinal axis LA laterally offset to the central axis of the lamp LM arranged. The light exit surface is in the offset direction down towards the circuit board 12 inclined and plan trained. Regarding the reflection surfaces 25 and 26 is the light guide 15 from the first, curved reflection surface 25 away in the direction of the second reflection surface 26 added.

As a result of this offset and the curvature of the first reflection surface 25 and the formation of the second reflection surface 26 as oblique surface meets the first reflection surface 25 light entrance surfaces close to the light guide 15 , The second reflection surface 26 on the other hand, light entry surfaces are far away from the light guide 25 , Ideally, the lowest point is towards the circuit board 12 inclined light exit surface in the of the second reflection surface 26 spanned level. Due to this special training -the asymmetrically designed reflector 20 with its first, curved reflection surface 25 and its second, designed as an inclined surface reflection surface 26 the lateral offset of the light guide 15 to the light center axis LM and the inclined light exit surface 16 - becomes a special radiation characteristic of the household appliance light 10 causes, which is explained below.

3 shows one of the 2 borrowed representation, in which for clarification of the facts explained below, the reflector 20 including cover glass 22 was omitted. In the 3 shown dash-dotted lines symbolically represent exemplary light rays from the LED 13 be emitted. First, in 3 Shown with D rays of light, which from the light exit surface 17 emerge and be referred to as so-called direct light. This direct light D leaves the light exit surface 17 in a certain beam angle, the opening angle of the light exit surface 17 leaving the light cone.

Also shown are exemplary light rays S , which due to their angle of incidence at the light exit surface 17 reflected, in the light guide 15 be thrown back and emerge from the lateral surface. These light rays designated S represent the so-called scattered light. 3 shows that this stray light S instead of in the direction of not shown, the light exit opening of the lamp 10 covering glass pane 22 back in the direction of the luminaire housing 14 to be thrown. They are thus not available for the illumination of the domestic appliance interior and can definitely be described as loss radiation.

In 3 it can also be seen that the cone axis shown in dotted lines K of the light guide 15 leaving light cone due to the inclination of the light exit surface 17 tilted from the vertical in the tilt direction. As a result, this becomes the light guide 15 leaving light substantially from the light center axis LM or optical fiber longitudinal axis LA directed away.

4 essentially corresponds 2 , whereby here also exemplary dash-dotted lines are drawn, which are for the LED 13 leaving light rays. Based on 4 can be explained very well the effect of the reflector.

As 4 can be seen, the scattered light rays S from the first, curved reflection surface 25 taken and in the direction of cover 21 and thus in the direction of the light exit opening of the luminaire 10 thrown. The curvature of the reflection surface is dimensioned such that it reflects the scattered light in the offset direction of the light guide 15 , ie essentially in the direction of the cone axis K toss. This takes the first reflection surface 25 only the stray light S for reflection on that from the light guide 15 exiting direct light D meets due to the arrangement of the light guide 15 within the reflection space 29 not on the first reflection surface 25 ,

The second reflection surface 26 is due to their position and inclination to the light guide 15 functionless and thus reflects no light. This is insofar for the overall radiation characteristics of the lamp 10 relevant as the second reflection surface 26 if they would perform a reflective function the light would be against the cone axis K reflected.

How out 4 Finally, it can be seen, leads the offset of the light guide 15 relative to the lamp central axis LM to that towards the first reflection surface 25 pointing lateral surface maximizes and thus the utilization of the scattered light S taking into account the desired reflection direction to the cone axis K is optimized. That the light exit opening of the household appliance light 10 or the cover 21 leaving light forms a beam, which also total in the direction of displacement of the light guide 15 is tilted and thus has a tendency.

If now the luminaire according to the invention is installed in such a household appliance, in particular a cooking appliance, that the first reflection surface 25 points away from an interior opening, so this the scattered light rays S into the household appliance interior and thus also the cone axis K of the light exit surface 17 leaving light cone is directed into the home appliance interior, a dazzling effect of a user is effectively avoided.

To the light output of the household appliance light 10 to further optimize, are the mounting arms 30 , which in Lichtleiternuten 31 intervene and the light guide 15 in the luminaire housing 14 hold in an area of the light guide 15 arranged in which due to the given LED beam angle no light rays impinge. This ensures that the light guide of the light guide 15 is not adversely affected.

In summary, the invention provides a domestic appliance light 10 ago, which by a combination of light guide 15 , one with asymmetric reflection surfaces 25 and 26 provided reflector 20 and finally by an offset of the light guide 15 to the light center axis LM has a special radiation characteristics, which allows a glare-free illumination of a domestic appliance interior. In addition, the light output is supported by the desired radiation characteristic supporting use of scattered radiation S of the light guide 15 significantly improved. The light guide 15 allows the spaced arrangement of the LED 13 from the domestic appliance interior, especially when it is a cooking space. The reflector 20 In addition, not only serves to reflect the scattered light radiation S but also to reflect the exiting from a cooking heat radiation. In this way, the home appliance light 10 be compact so that it is also suitable for installation in home appliance side walls.

LIST OF REFERENCE NUMBERS

10

Hausgeräte light

11

heatsink

12

circuit board

13

LED

14

luminaire housing

15

optical fiber

16

Light entry surface

17

Light-emitting surface

18

recess

19

detent spring

20

reflector

21

cover

22

pane

23

connecting conductors

24

Connectors

25

first reflection surface

26

second reflection surface

27

Reflector sidewall

28

apex axis

29

reflector

30

mounting arms

31

Lichtleiternuten

K

cone axis

R

locking element

S

scattered light

D

direct light

LM

Lights central axis

LA

Longitudinal axis of 15

Claims (10)

Household appliance lamp (10) for cooking appliances, such as ovens, microwave ovens or steamer, - with a LED (13) as a light source, - with a provided for installation on a device wall luminaire housing (14), - with a light exit opening (17) in the luminaire housing (14) which is closed by a light-permeable cover (21), - with a spacer element, which is arranged between the LED (13) and the light exit opening (17) and sits in front of the light exit plane of the LED (13), - with a reflection means, which the of the LED (13) emitted light of the cover (21), characterized in that - the spacer element is a uniform material light guide (15) which receives the light of the LED and bundles, - the entire light exit surface (17) of the light guide (15) is provided with a uniform inclination relative to a central axis (LA) of the light guide (15) and thus the cone axis (K) of the light exit surface (17) emerging light cone is also relative to the central axis (LA) of the light guide (15) is inclined - the reflection means is a reflector (20) which spans a reflector space (29), - the light guide (15) is guided into the reflector space (29) , - the reflector (20) essentially directs the scattered radiation (S) emerging from the light guide (15) in the direction of the cover (21). Appliance light after Claim 1 , characterized in that the reflector (20) directs the light predominantly in the direction of the cone axis (K) of the light cone emerging from the light exit surface (17) of the light guide (15). Domestic appliance lamp according to one of the preceding claims, characterized in that the reflector (20) has two apex axis (28) springing web-shaped reflection surfaces (25/26), wherein the apex axis (28) near a light entry surface (16) of the light guide (15) is arranged. Appliance light after Claim 3 , characterized in that the first, web-shaped reflection surface (25) is curved about a to the apex axis (28) parallel axis of curvature. Appliance light after Claim 4 , characterized in that the first, curved reflection surface (25) is guided into a region of the light guide (15) which is close to the light entry surface. Appliance light after Claim 5 , characterized in that the area near the light entrance surface lies below a plane in which the marginal rays of the beam cone defined by the emission angle of the LED (13) strike the boundary surfaces of the light conductor shell. Household appliance light after Claim 3 , characterized in that the light guide (15) to the apex axis (28) of the web-shaped reflecting surfaces (25/26) is laterally offset. Appliance light after Claim 1 and 7 , characterized in that the inclined light exit surface (17) of the light guide (15) decreases in the direction of the lateral offset. Appliance light after Claim 3 and 8th , characterized in that the second sheet-shaped reflection surface (26) is unbent and guided to the light entry surface near transition region of the light exit surface (17) and the photoconductive surface, wherein the inclination of the second reflection surface (26) with respect to the cone axis (K) of the light exit surface (17) emerges light cone substantially to the inefficiency of the second reflection surface (26) leads. Domestic appliance light according to one of the preceding claims, characterized in that the reflector (20) and the immersion depth of the light guide (15) in the reflector space (29) are matched to one another such that the reflector (20) only from the light guide (15) exiting Scattered radiation (S), but not from the light exit surface (17) emerging direct radiation (D) reflected.

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