Patent Application
20240151387
This patent application claims the benefit of and priority to German Patent Application No. 102022129298.3, filed on Nov. 7, 2022, which is herein incorporated by reference in its entirety.
The invention relates to a household appliance, in particular selected from a group consisting of a dishwasher, a washing machine, and an oven, with a light beam projection device for projecting light beams onto a room floor surface located outside the household appliance according to the preamble of the claim 1.
Dishwashers, washing machines or ovens, especially in the newer generation, are often provided with a light source which serves to project a light spot onto the floor on which this appliance is located, for example to indicate that the dishwasher, oven or washing machine is currently in operation. That is, as soon as, for example, a dishwasher is started by a user and the door of the dishwasher, such as the front door, is closed, a light spot is perceived on the floor below this front door. Such light sources are usually always LEDs, which are characterized by spontaneous emission.
The disadvantage of LEDs used in this way is that only a low contrast of the light spot on the floor is achieved. This is due on the one hand to the length of the emission module and on the other hand to the low focal depth of the LED. Neither can desired patterns be imaged on the floor or room floor surface, nor can reliable light spots be perceived depending on the floor surface and the current daylight in the room.
Thus, it is the object of the invention to provide a household appliance with a light beam projection device, which enables a reliable perception of a light image on a surface not belonging to the household appliance.
This object is solved according to the features of claim 1.
Advantageously, a household appliance, in particular selected from a group consisting of a dishwasher, a washing machine and an oven with a light beam projection device for projecting light beams onto a room floor surface lying outside the household appliance, comprises as light source a laser light source which is arranged directly in a floor area of the household appliance facing the room floor surface in such a way that its light beam emitting laser light source output is directed directly onto the room floor surface. By using such a laser or such laser light sources, an excited emission takes place during the light emission instead of a spontaneous emission, whereby a correspondingly bright and sharp light image can be obtained on, for example, a room floor surface in the case of an active operating state of a dishwasher. The use of such laser light beams allows not only reliable detection of the laser beam on the floor in any daylight and also in sunlight, but also the possible generation of a certain desired light image form on the floor, such as the lettering of a company name, to which this household appliance has a reference. Due to the use of a laser light source, correspondingly sharp border areas are obtained, which can thus reflect different state statuses.
An essential point is that when using a laser light source, a stimulated or excited emission takes place instead of a spontaneous emission for the emission of the light beams. This has the consequence that with a stimulated emission not only a large coherence length but also a high amplitude stability of the emitted light beams is present. Such laser radiation is thus suitable for producing more intense light beams or a high light intensity and for achieving a corresponding sharpness in the image. Thus, for example, text fields and other patterns with arbitrarily small recesses can be obtained when using a correspondingly shaped aperture on the floor or room floor surface.
Preferably, laser diodes are used for such Laser light sources, which can be equipped with corresponding integrated optics.
In order to obtain such light patterns or images on the floor or room floor surface, at least one aperture device, preferably a pinhole aperture or an electro-optical aperture or also apertures for producing image patterns, can be arranged in the laser light beams between the laser light source output and the room floor surface. This enables a targeted selection of laser light beams to pass through the aperture or apertures in order to obtain an appropriately sharp image on the room floor surface. Such an aperture can be arranged in front of the laser light source output directly at the lower exit of the light beams within the housing or within a front door in the floor area. Ideally, such a pinhole is also already integrated in the housing or in the door of the household appliance in the floor area. Alternatively, an LCD display can be used, which can also be designed in one color.
Alternatively or additionally a defocusing objective device can be arranged between the laser light source output and the room floor surface. This can be, for example, one or more concave lenses that expand the laser beam and thus defocus it in order to obtain, for example, a larger area of the light image on the floor or room floor surface. If this image or the light image on the floor is nevertheless to be limited to finite dimensions, an aperture can additionally be arranged between the defocusing optics and the room floor surface, which allows a large portion of the light rays to pass through a correspondingly large opening, but a finite portion in relation to the cross section for imaging on the room floor surface.
Alternatively or additionally, one or more convex lenses can be arranged between the laser light source output and the room floor surface, which can be arranged at a predeterminable distance from the laser light source depending on their focus length. In addition, an aperture can be arranged between this convex lens and the room floor surface. Depending on the distance to the laser light source this convex lens is arranged, a different imaging area of a laser light spot on the room floor surface is achieved. Thus, a focusing of the laser light beams to a spot at the location of the room floor surface, a collimation to a laser light beam or a not complete focusing can be achieved.
For example, a laser light source in the form of a laser diode or laser module, a defocusing objective device and a convex lens device can be arranged one behind the other. A aperture device can also be located downstream. This makes it possible for the defocusing objective device first to expand the laser light beams and then to obtain a parallelization of the laser light beams at the location of the room floor surface by means of the convex lens device. This makes it possible to obtain a desired light image with exact marginal areas when using an aperture device and to read the text accurately when using a text-imaging aperture.
In addition, in such an arrangement the defocusing objective device as well as the convex lens device can be designed to be movable relative to each other as well as to the laser light source and a pinhole in order to obtain the previously mentioned light spot sizes on the room floor surface in the desired form.
In particular, when using a laser diode, a lens or lens device that is not symmetrical in its cross-section is preferably used in order to achieve a compensation of fast and slow laser axes, which are often present in laser diodes.
Due to the high focal depth of the laser light sources, one or more light spots generated on the room floor surface can also be actively changed in their position on the surface and generate a warning sign. This can emphasize corresponding warning messages, for example. An interrupted light beam as an image on the floor surface is also conceivable in order to be able to reproduce a kind of alarm signal. Similarly, fast and slow laser axes with different divergence angles can be used to reproduce broad lettering on the floor surface.
In this context, it is also conceivable that the laser light beams are split into several light beams, which can be done by means of appropriately designed aperture devices or by laser light beam splitting. As a result, a plurality of light beam spots can be detected on the room floor surface.
If a two- or multi-colored logo or the like from a manufacturer of the household appliance is to be displayed on the room floor surface, it is conceivable that LCD surfaces are used which are excited by the optical polarization of the laser light beams with different wavelengths and produce a multi-colored logo or similar pattern on the room floor surface. This makes the arrangement of several apertures within one aperture device unnecessary. This requires more than one laser source and different wavelengths of laser beams.
The use of a multi-color image and also the desired image of a character consisting of several colors whose colors change can be achieved, for example, by the number of lasers being more than one laser or by using a laser in combination with an LED as a further light source. Hereby, this plurality of laser light sources can be activated differently and thus a color change in the image on the room floor surface can be achieved.
Laser light sources whose wavelength can be changed to produce different colors are also conceivable.
It is also possible to arrange a fluorescent material in the form of a surface element in the optical path or on the path between the laser light source output and the room floor surface, which contributes to different fluorescence images on the room floor surface through excitation by the laser light beams.
Such a fluorescent material can be changed in its properties and color reproduction not only mechanically, but also by optical excitation energy and its change.
Additive color mixtures are also conceivable for bringing about color combinations and color changes by introducing corresponding elements into the optical path.
Preferably, an intensity device for laser light beams is also conceivable in the light path or in the optical path, which enables the intensity of the Laser light beam to be changed.
It is conceivable that line or cross lasers are used, for example, in order to be able to image desired exact line structures.
Further advantageous embodiments result from the sub-claims in connection with the following drawing:
It shows:
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At the lower end of the front door 3, which may for example be the door of a dishwasher, the light beam projection device 4 is arranged in the lower region, i.e. in the floor region to a room floor surface 5, which is oriented in such a way that the laser light beams emerging from a laser light source output are directed directly onto the room floor surface 5. Accordingly, these laser light beams 6 are not guided through a light guide or the like to an exit opening in the floor area of the front door 3, but are directed within the light beam projection device with said laser light source directly onto a floor or room floor surface 5.
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It can also be seen from this illustration that according to double arrow 31 a displacement of the convex lens 30 is conceivable in order to thus produce different distances from this convex lens 30 to the laser light source output 11.
If a distance 32 is greater than a focus length of the convex lens 30, a focusing of the laser light beams to the size of a desired light spot takes place, which is subsequently imaged on the room floor surface 5 in a finite cross-sectional size.
If the distance 32 corresponds to the focus length of the convex lens 30 or the associated lenses, i.e. is identical, collimation of the laser beam or the laser light beams is achieved. This means that all laser light beams are brought onto a mutually parallel path and a correspondingly large light image is produced on the room floor surface 5. Thus, an increase in the cross-sectional area of the laser spot in the area of the room floor surface can be obtained.
If the distance 32 is smaller than the focus length of the lenses belonging to the convex lens arrangement 30, an expansion of the laser light beams and thus of the laser spot of the desired size is obtained and thus a larger cross-sectional image, for example in the form of a circle, is obtained at the location of the room floor surface 5, since no complete focusing of the laser light beams takes place.
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By such an arrangement of objective devices, first an expansion of the laser light beams 6 and subsequently a parallelization or also a bundling of the laser light beams after exit from the convex lens device 41 can be obtained. Which of these parallelized or largely parallelized laser light beams are to pass through the aperture 42 for imaging on the room floor surface 5 with a desired cross-sectional area size is determined by the size of the opening in the aperture 42. This opening in the aperture can, of course, have a wide variety of shapes. For example, the shape of a square, a circle, or even the shape of a text, a word, a pictorial representation, a logo, etc.
In principle, any type of lens system can be used, i.e. also the systems not shown in more detail here.
It is also conceivable to arrange several mirrors for multiple deflection of a laser light beam.
Such a mirror 60 can in principle be arranged at any point of the beam path, for example directly at the laser light output 11 or also in the vicinity of a light output at the lower end of the household appliance, i.e. in the vicinity of the room floor surface. For this purpose, the laser module and the direction of a laser light beams, which emerges from the laser light source output, can have any conceivable angle in its orientation, as long as by means of the mirror 60 a sufficiently focusing deflection takes place in the direction of a room floor surface and, if necessary, focusing devices 50, 51, 52 set up therebetween.
Such a mirror 60 can be designed as a plane and flat mirror or also have a concave or convex shape. This mirror can advantageously be either stationary or, for example by means of a motor drive or MEMS, movable and, if necessary, pivotable in order to obtain better focusing and deflection properties. For example, when the laser light source is installed or removed, it may be necessary to refocus, which would be possible with such a mirror. However, certain desired images on the room floor surface can also be obtained by a moving mirror 60 along different shifting axes or a tilting.
The mirror may be a simple mirror or a multifaceted mirror.
The two Lens devices 50,51 are preferably fixed in their position when a mirror 60 is used. The position of these devices and their optical properties define the focusing, defocusing and spot size adjustment process.
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| Number | Date | Country | Kind |
|---|---|---|---|
| 102022129298.3 | Nov 2022 | DE | national |
