EP3232428B1 - Display element, display device with such a display element and electric device with such a display device - Google Patents

Description

Field of application and state of the art

The invention relates to a display element for a display device, a display device provided with such a display element and an electrical device with such a display device.

Display elements for a display device, which have a light display function and moreover even an operating function, are from the EP 2809006 A1 known. In a display housing there is a light-guiding channel in the form of a light-guiding body, which is enclosed laterally in an opaque manner, so that light can only emerge on its upper side. The light guide channel is surrounded in a frame-like manner by elastic material which is electrically conductive and has a capacitive sensor element for the operating function. Such display elements can be provided with an operating function as corresponding illuminated capacitive sensor elements. Possible arrangements of a large number of such display elements with an operating function are shown in FIG DE 102009049559 A1 basically known.

From the DE 10 2012 010 321 A1 An operating and display element for a display device is known, which also has a light display function. Elastic, electrically conductive plastic is provided at the top of a display housing and runs downward. At the bottom, it protrudes above an underside of the display housing and can be pressed onto a contact field on a printed circuit board or the like for electrical contacting. On the underside, this electrically conductive material lies next to one of two holding members.

From the DE 10 2008 027 220 A1 a pure display device with display elements is known. The display device is arcuate, and by means of a light display function, a hot display can be created directly next to a hotplate in an electric hob.

Task and solution

The invention has for its object to provide a display element mentioned above, a display device provided with it and an electrical device provided therewith, with which problems of the prior art can be solved and in particular it is possible to create a practical design of a display element that can be pressed in particular on an underside of a display control panel or a cover and is thereby protected against damage, in particular on the top of the light guide channel.

This object is achieved by a display element with the features of claim 1, by a display device provided with the features of claim 9 and by an electrical device provided with the features of claim 12. Advantageous and preferred embodiments of the invention are the subject of the further claims and are explained in more detail below. Some of the features are described only for the display element, only for the display device or only for the electrical device. However, they should be independent of this both for the display element and for the display device and the electrical device can apply independently. The wording of the claims is made the content of the description by express reference.

For a luminous display function, the display element has a display housing and a light channel therein, which extends continuously from a bottom to an upper side of the display housing. The light guide channel is made of translucent material, advantageously completely transparent for optimal light output or translucent for homogenizing a light display. A light source is advantageously provided under the underside of the light channel, for example at least one LED or SMD LED. The light guide channel is closed or surrounded to the side so that there is no undesired lighting effect to the side, which could adversely affect the light display function from above. An opaque coating is applied to the light guide channel on the top of the display housing, for example by means of a dipping process or alternatively sprayed on. This opaque coating can be a kind of lacquer. It can either be removed during the production of the display element itself or later in some areas, so that a cutout is formed therein, which determines the light display with its shape. This is known in principle and is also explained in more detail below.

Spacers are provided on at least two outer sides of the display housing, which protrude above or are higher than the upper side of the light guide channel, that is to say they protrude upward above the upper side of the light channel. The material of the spacers is electrically conductive for an operating function and thus forms a capacitive sensor element on the top of the display element, as a result of which a capacitive operating sensor is formed. These spacers, which are made of non-elastic material and / or are non-elastic, are used so that they are in contact with an underside of a display control panel or a cover and that the top side of the light guide channel with the coating cannot be in contact with this underside . This could cause the coating on the top to be damaged or removed, which could result in undesired lighting effects. The spacers thus form a non-elastic and therefore secure protection for the top.

A height of the spacers can be variable, in particular also depend on the size of the display element. The height of the spacers is advantageously about 0.5% to 10% of the height of the entire display element. The spacers should not be too large so that the distance between the top of the light guide channel and the bottom of the control panel cover is not too big. The light display function can still be recognized sufficiently well or results in a sufficiently sharp image.

In an embodiment of the invention, the light guide channel can be surrounded on the side by opaque plastic, advantageously be completely surrounded. It is particularly advantageously possible to produce this in a multi-component injection molding process, for example from polycarbonate or two different materials based on polycarbonate. An underside of the light guide channel is provided or left free for light to enter from a light source arranged underneath. The top of the light channel has the opaque coating, in which at least one cutout in the form of one or more symbols can be provided for the light display function. In a preferred embodiment of the invention, the coating also covers the spacers and thus the entire upper side or possibly even the entire upper area of the display element. The coating can also be provided on the sides and / or cover them completely. The coating is an easily removable lacquer or can advantageously be removed by means of a laser, so that the aforementioned cutouts in the form of a symbol or a plurality of symbols can be produced therein relatively easily and without contact, in order to adapt the light display function.

In a further embodiment of the invention, the spacers can be provided at least on opposite sides of the display housing. This has the advantage that the possibly force-loaded contact of the display element on the underside of a display control panel is uniform or plane-parallel to the top of the light guide channel. The spacers advantageously each extend essentially over the full width of this side, under certain circumstances the corner regions can be excluded. The spacers are particularly advantageously formed on all sides of the display housing so that they frame the top of the light guide channel. They prefer to frame them without interruption, ie they are continuous. Small interruptions in the longitudinal course of the spacers can be provided, for example to allow air to be brought up to the top of the light guide channel.

The spacer material is advantageously polycarbonate, but an opaque one. It can also be injection molded onto the light guide channel in a multi-component injection molding process, which is easier with basically similar material.

It is possible to provide a spacer on a lateral outer wall of the display housing, this lateral outer wall enclosing the outside of the light guide channel or forming an outside of the display housing, all outer walls advantageously being formed all around and enveloping the light guide channel to the side. All spacers of the display element can be provided on outer walls particularly advantageously.

In an embodiment of the invention it can be provided that at least in a lower region of the light guide channel, a reflector which at least partially delimits the light guide channel laterally outwards and / or downwards is provided. This reflector is made of opaque material, and is covered by the material of the spacers on short outer sides of an elongated display housing. On long outer sides of an elongated display housing, it can be uncovered laterally outwards, that is to say form an aforementioned outer side or outer wall. Above all, such a reflector runs partially at an angle to the top of the light guide channel, in order to deflect as much light as possible upwards from a light source arranged under the light guide channel for a highly visible light display function. The material of such a reflector should be selected in such a way that when it is brought together with a translucent material of the light-guiding channel, it has the best possible reflective effect at the interface of the two materials.

If a display housing is elongated, that is to say not square, it can be provided that at least one holding member projecting downwards and projecting downwards over an underside of the light guide channel is provided on short outer sides of the display housing. There is more space on these short outer sides for an elongated display housing than on the long outer sides. If the display housing is rather square, it does not matter which outer sides such holding members are provided for. According to the invention, they are provided on opposite outer sides for stable fastening on a component carrier.

In an advantageous embodiment of the invention, the opaque coating which is applied to the top of the light guide channel can also be applied to all the lateral outer sides and the other surface or top of the display housing. In particular, it can also be applied to the spacers, in which case it serves no purpose here, but it must be ensured that the top of the light guide channel is completely covered.

In a further embodiment of the invention, the light guide channel can be surrounded in its upper region by opaque material. This opaque material can form a peripheral edge, which can for example form a flat plane with the top of the light guide channel. The opaque material then corresponds to the aforementioned outer sides or outer walls of the display housing made of opaque material.

The spacers can be at least partially placed or integrally formed on the aforementioned edge on the outer walls around the light guide channel. The spacers are advantageously offset 5% to 50% of the width of the edge away from the light guide channel and are at a distance, that is to say they are somewhat spaced from the boundary between the inner light guide channel and the outer edge or outer wall. This has the sense that the spacers are advantageously also covered by the same opaque coating as part of the top of the light guide channel. If the coating on the top of the spacers is scraped away by the spacers resting on the underside of a display control panel, there is a risk that flaking on the lateral sides of the spacers will also release a side area of the top of the light guide channel, primarily because of manufacturing tolerances. Then there could be an undesired lighting effect here. Furthermore, the application of the coating to one side of a spacer, which goes up directly from the border between the edge and the light guide channel, is not so easy. By moving the spacers a bit away from the boundary between the light guide channel and the edge, these problems are avoided. A distance of the spacers from the light guide channel can be at least 0.05 mm to 0.1 mm.

According to the invention, electrical contacting to the capacitive sensor element or to the capacitive control sensor takes place in that electrically conductive material contacts or comes off the spacer and is easily electrically contactable, for example on a component carrier on which the display element is placed.

According to the invention, the electrically conductive material of the spacers is integrally connected to the spacers or forms them in one piece. The material integrally merges into the above-mentioned holding members for producing an electrical contact. For this purpose, there can be at least one hole in the component carrier as a receiving opening, into which a holding member is inserted. Electrical contacting takes place here, for example by inserting the receiving openings in the component carrier on the inside are electrically conductive coated and thus the electrically conductive spacers automatically make electrical contact when pressed.

A display element advantageously has a light guide body made of translucent or transparent material. In a lower region of the light-guiding channel, a reflector can be provided or injection molded around it. This covers the light guide channel to the side against undesired light emission and ensures that the light is intensified upwards. At least in the upper area, the light guide channel is surrounded on all its sides with electrically conductive and opaque material, which forms outer walls which actually protrude to the top of the light guide channel or form an essentially flat plane with them. The spacers are then formed on these edges at the top or protrude upward from the edges.

A cross section or a profile of such a spacer is advantageously essentially rectangular. Because they are non-elastic, the spacers ensure in any case that when the display elements are pressed onto the undersides of display control panels or covers, which under certain circumstances are not quite level, the sensitive coating's upper sides are not impaired or destroyed or get scratched.

A display device according to the invention can have a component carrier on which a plurality of electrical functional units, in particular a controller and also other parts, are arranged. At least one display element according to the invention is arranged on the component carrier, advantageously several. For this purpose, the DE 102009049559 A1 referred.

A light source for the light display function is arranged below the light channel of the display element on the component carrier. A plurality of light sources or LEDs can advantageously be provided per display element below the light channel. Either a brighter lighting effect or a switchable color of a light indicator function can be achieved.

A aforementioned hole can also be provided on the named component carrier, into which a holding member can be inserted for fastening the display element. Since the holding member advantageously also consists of electrically conductive plastic, electrical contacting can take place here. The hole on the inside can be electrically conductive be coated, advantageously as a so-called via. When the holding member is pressed in, there is an electrical contact that is permanent and reliable.

An electrical device according to the invention has a display control panel or a cover, under which a display device according to the invention is arranged. The display device or display elements arranged thereon are advantageously pressed onto an underside of the display control panel or the cover. In a preferred embodiment of the invention, the electrical appliance is a cooking appliance, in particular a hob. Hobs with glass ceramic cooktops often have a rough underside on the cooktop, also known as knobs. These knobs with a width of a few mm and a height of less than 1 mm could damage the coating on the top of the light guide channel in such a way that undesired light phenomena could occur.

The spacers can be made of carbon fibers or the like. plastic or polycarbonate made conductive. Alternatively, carbon black or graphite could also be used. An ohmic resistance is in the range of less than 300 Ω to 3 kΩ, so it is relatively good conductor.

These and other features emerge from the claims and also from the description and the drawings, the individual features being realized individually or in groups in the form of sub-combinations in one embodiment of the invention and in other fields and being advantageous and protectable per se Can represent versions for which protection is claimed here. The division of the application into individual sections and subheadings do not limit the general validity of the statements made under these.

Brief description of the drawings

Fig. 1

eine seitliche Schnittansicht durch ein erfindungsgemäßes Kochfeld als Elektrogerät mit einer Anzeigevorrichtung mit einem erfindungsgemäßen Anzeigeelement,

Fig. 2

einen Querschnitt durch das Anzeigeelement aus Fig. 1 ohne die Anzeigevorrichtung,

Fig. 3

eine Draufsicht auf das Anzeigeelement aus Fig. 1 ohne Anzeigevorrichtung,

Fig. 4

eine Unteransicht des Anzeigeelements,

Fig. 5

eine Ansicht auf die kurze Außenseite von außen des Anzeigeelements und

Fig. 6

zwei verschiedene angedeutete Varianten von Anzeigeelementen mit mehreren LED als Lichtquellen darunter.

Exemplary embodiments of the invention are shown schematically in the drawings and are explained in more detail below. The drawings show:

Fig. 1

2 shows a sectional side view through an inventive hob as an electrical device with a display device with a display element according to the invention,

Fig. 2

a cross section through the display element Fig. 1 without the display device,

Fig. 3

a plan view of the display element Fig. 1 without display device,

Fig. 4

a bottom view of the display element,

Fig. 5

a view of the short outside from the outside of the display element and

Fig. 6

two different indicated variants of display elements with several LEDs as light sources below.

Detailed description of the exemplary embodiments

In the Fig. 1 is a sectional view through a hob 11 according to the invention as an electrical device, as this essentially also Fig. 1 the aforementioned EP 2809006 A1 corresponds. The cooktop 11 has a cooktop plate 13, advantageously made of conventional glass ceramic material with a reddish-brown color and low translucency. An underside of the cooktop plate 13 has the knobs 15 known for this, which are spaced a few millimeters apart and have a height of 0.05 mm to 0.1 mm. A finger can be placed on an upper side 16 of the cooktop plate 13 for the above-mentioned operating function with a capacitive sensor element. Furthermore, on the top 16 of the cooktop 13, the light display, as can be seen in particular with reference to FIG Fig. 3 is well imaginable.

A display device 18 under the hob plate 13 or which bears on the underside 14 with the knobs 15 has a plurality of display elements 20, only one being shown here. The display element 20 is essentially block-shaped and has a display housing 22, as is known in principle from the prior art. Within the display housing 22, a light guide channel 24 is formed from translucent material, advantageously completely transparent polycarbonate. The light guide channel 24 as a component has an underside 25 and an upper side 26. A free space 27 is formed on the underside 25 for arranging a light source 40 below it. In the sectional view of the Fig. 1 a reflector 28 is formed on the left and right of the light guide channel 24 or on its sides pointing obliquely downwards and outwards. The reflector 28 is made of opaque material, advantageously also polycarbonate, and can be particularly advantageously sprayed together with the light guide channel 24 in a aforementioned multiple spraying process. The interfaces between the two form a light-reflecting surface in order to reflect as much light as possible upwards towards the top side 26. The reflector 28 runs like the other Sectional view of the Fig. 2 shows, along the longer outer sides also laterally along the light guide channel 24, but only up to a certain height, as is already the case in FIG Fig. 1 can be seen. Along these longer outer sides, part of the reflector 28 is open to the outside, but this is not a problem.

The in the Fig. 1 Outer walls 30a and 30c shown in section are made of a third material, namely an electrically conductive material. This is advantageously a previously mentioned electrically conductive polycarbonate, which is opaque and thus, like the reflector 28, closes the light guide channel 24 to the side. In this way, no undesired lighting effects can occur. The left outer wall 30a extends up to an upper side 26 of the light guide channel 24 and forms one there Fig. 3 peripheral edge visible in plan view. A spacer 32a is placed on this edge. As the illustrations clearly show, the spacer 32a is both slightly offset inwards from the outside of the outer wall 30a and also slightly set back from the transition to the top side 26 of the light guide channel 24. This also applies to the spacers 32b to 32d of the remaining outer walls 30b to 30d. Like the sectional view of the Fig. 2 shows well, the outer wall 30b and 30d is not particularly high along the longer outer sides of the display housing 22 and in particular is placed on an upper edge of the reflector 28. A stepped contour can be provided here for better connection of the two areas.

The material of the outer walls 30a to 30d and the spacers 32a to 32d is made electrically conductive in the aforementioned manner, advantageously by adding short carbon fibers, soot or graphite. As a result, it forms a frame-like, encircling capacitive sensor element, which in the Fig. 3 can be seen in plan view. Its function corresponds approximately to the capacitive sensor element, as it is from the aforementioned EP 2809006 A1 is known. However, here it consists of a non-elastic material, advantageously polycarbonate again, and is non-elastic. Its deformability, which, however, is only accompanied by destruction, is not considered a non-elastic property in the context of the invention. The recognizable thin material thickness or width b of the spacers 32a to 32d with about 0.2 mm to 0.3 mm also does not give them any elasticity.

Like from the 1 and 2 Is clearly recognizable, the spacers 32a to 32d protrude with the height h over the top 26 of the light guide channel 24 and thus protect it. Since the spacers 32a to 32d are higher than the knobs 15 on the underside 14 of the hob plate 13, for example by at least 0.05 mm and because of their non-elastic structure, they thus protect this top side 26.

On the top 26 or on the entire upper area of the display element 20 and thus also on the spacers 32 and at least the upper areas of the outer walls 30a to 30d, an aforementioned opaque coating 42 is applied, which is only in the Fig. 3 is shown directly, but is easily imaginable for the person skilled in the art. This coating 42 is opaque to the light from a light source 40 with the light intensity usually used for such display devices 18. The coating 42 can have a low thickness of less than 0.1 mm, it just has to be opaque. It can be a kind of lacquer or elastic coating that has been permanently applied to the display housing 22 and, above all, the top side 26. A cutout 43 in symbol form, here as "F", can then be introduced into the coating 42 on the upper side 26, advantageously by means of a laser. Several cutouts can also be made, which is not a problem with a laser. At this cutout 43, light in its form can therefore emerge from the light guide channel 24 for the abovementioned light display function and can be recognized from above as a luminous “F” through the hob plate 13. Here it is easy to imagine how, if this top side 26 with the coating 42 bears directly against the knobs 15 of the underside 14 of the cooktop plate 13, damage to the coating 42 would be possible and likely, as a result of which light will then escape in an undesired manner at undesired points. The spacers 32a to 32d mentioned are provided for this.

The small lateral distance a of the spacers 32a to 32d to the boundary between the top 26 and the outer wall 30a to 30d, which is particularly in the top view of FIG Fig. 3 and the sectional views of the 1 and 2 It becomes clear that the coating 42 on the top of the spacers is highly likely to be at least partially scraped off by the knobs 15. If the coating 42 then dissolves in somewhat larger pieces, the inner edge at the foot of the spacers 32a to is still 32d is present, where the coating 42 is deposited in a somewhat thicker material and thus does not come off so easily. The distance a to the upper side 26 above the light guide channel 24 ensures that the coating 42 remains on this upper side.

In order to make electrical contacting of the capacitive sensor elements formed by the spacers 32a to 32d downward, the short lateral outer walls 30a and 30c merge downward into holding members 34a and 34b. These are electrically conductive because the entire continuous material is electrically conductive, advantageously the aforementioned electrically conductive and opaque polycarbonate. As the Fig. 1 easily shows and is also known from the prior art, the holding members 34a and 34b are inserted and pressed into holes 37a and 37b of a component carrier 36 of the display device 18, that is to say hold non-positive, possibly due to slight deformation. The inside of the holes 37a and 37b are coated in an electrically conductive manner, advantageously as so-called vias, as are known from printed circuit board technology and can also be easily provided in the component carrier 36, which is advantageously a conventional printed circuit board. From the holes 37a and 37b or their electrical contacts, conventional conductor tracks can go to a control of the display device, which is not shown here. Similar conductor tracks also contact an LED 40 as a light source in the free space 27 under the underside 25 of the light guide channel 24. From the sectional view of FIG 1 and 2 it can also be seen that the display housing 22 extends around the LED 40 up to the component carrier 36 and thus prevents light radiation to the outside. This is done by the reflector 28 surrounding the LED 40, which is pulled down to the component carrier 36.

From the Fig. 6 can be seen how schematically the representation of the Fig. 4 accordingly, not only a single LED 40 can be provided, but two LED 40. Four LED 40 could even be provided. It is with the Fig. 6 it is possible that two or even more colors are provided by differently colored LEDs for a more variable illuminated display.

The innovation of the present invention thus essentially consists in the provision of the spacers 32a to 32d, which run around the top 26 of the light guide channel 24 and protrude above it and serve as protection. They are designed to be non-elastic in order to ensure the protection of the upper side 26 or the coating 42 thereon. Furthermore, they are electrically conductive and act as capacitive sensor elements for an operating function of the display device 18. They are electrically contacted via areas drawn downwards as lateral outer walls 30a and 30c, which merge into holding members 34a and 34b, which in turn are electrically contacted. A large number of such display elements 20, possibly also with different basic shapes, can correspond to those mentioned at the beginning DE 102009049559 A1 be provided on the component carrier 36 and form a display device 18, which also works as an operating device with capacitive touch sensors.

Claims (12)

1. Display element for a display device (18), wherein the display element (20) has a luminous display function and an operating function, the display element for the luminous display function comprising:

   - a display housing (22),

   - a light conducting channel (24) in the display housing (22), extending continuously from a bottom side (25) up to an upper side (26) of the display housing,

   - wherein the light conducting channel (24) is laterally closed and impervious to light,

   - on the upper side (26) of the display housing (22), an opaque coating (42) is applied on the light conducting channel (24),

   - at least on two outer sides of the display housing (22), inelastic spacers (32a-d) are provided, which spacers protrude beyond the upper side (26) of the light conducting channel (24) and which are composed of electrically conductive material for the operating function, in order to provide a capacitive sensor element on top of the display element (20) for a capacitive operating sensor,

   - on opposite outer sides (30a-d) of the display housing (22) are provided in each case one holding member (34a, 34b) projecting downwards and protruding downwards beyond a bottom side (25) of the light conducting channel (24),

   - wherein the electrically conductive spacers (32a-d) are configured to be electrically contacted downwards by means of electrically conductive material for electrical connection to the capacitive sensor element,
   characterized in that

   - the electrically conductive material of the spacers (32a-d), on the outer sides (30a-d) of the display housing (22), transitions integrally into the holding members (34a, 34b) for producing an electrical contact upon fastening of the display element (20) to the holding members (34a, 34b) on a component support (36),

   - thereby the holding members are inserted into corresponding holes (37a, 37b) in the component support.
2. Display element according to claim 1, characterized in that the light conducting channel (24) is laterally surrounded by opaque synthetic material (28, 30a-d), preferably is completely surrounded, wherein a bottom side (25) of the light conducting channel (24) is exposed for light input from a light source (40) below, and an upper side (26) of the light conducting channel (24) has an opaque coating (42), wherein in the opaque coating at least one aperture (43) in the form of a symbol or multiple symbols for the luminous display function is provided.
3. Display element according to claim 1 or 2, characterized in that the spacers (32a-d) are provided at least on opposite sides of the display housing (22), and preferably each extend across the entire width of said side, wherein in particular the spacers (32a-d) are provided on all sides completely circumferentially on the display housing (22) and border the upper side (26) of the light conducting channel (24).
4. Display element according to claim 3, characterized in that a spacer (32a-d) is provided on a lateral outer wall (30a-d) of the display housing (22), which wall is composed of opaque material and encloses the light conducting channel (24) on the outside or is an outer side of the display housing (22), wherein preferably all spacers are provided on circumferential outer walls.
5. Display element according to any of the preceding claims, characterized in that, at least in a lower region of the light conducting channel (24), a reflector (28) is provided and delimiting the light conducting channel at least partially laterally outwards and/or downwards, which reflector is composed of opaque material, wherein preferably the reflector is covered by the material of the spacers (32a, 32c) on short outer sides (30a, 30c) of the display housing (22), and is not covered laterally on the outside in particular on long outer sides (30b, 30d) of the display housing (22).
6. Display element according to any of the preceding claims, characterized in that the opaque coating (42) on the upper side (26) of the light conducting channel (24) is applied to all of the lateral outer sides (30a-d) and the other upper side (26) of the display housing (22), in particular also onto the spacers (32a-d).
7. Display element according to any of the preceding claims, characterized in that the light conducting channel (24) in the upper region thereof is surrounded by opaque material (30a-d) which forms a circumferential edge, wherein preferably the circumferential edge forms a planar plane with the upper side (26) of the light conducting channel (24).
8. Display element according to claim 7, characterized in that, on said edge, spacers (32a-d) are placed on, at least partially, wherein preferably the spacers (32a-d) are spaced offset outwards 5 % up to 50 % of the width of the edge from the boundary between edge and light conducting channel (24).
9. Display device (18) for arrangement in an electric appliance (11), characterized by a component support (36) having electric functional units (40) thereon, wherein at least one display element (20) according to any of the preceding claims is arranged thereon.
10. Display device according to claim 9, characterized in that the light source (40) for the luminous display function is disposed on the component support (36) below the light conducting channel (24) of the display element (20), wherein preferably a plurality of LEDs (40) are disposed below the light conducting channel (24) of a single display element (20).
11. Display device according to claim 9 or 10, characterized in that an electrical contact to the display element (20) is achieved via an electrically conductive hole (37a, 37b) in the component support (36), where the retaining member (34a, 34b) is plugged in.
12. Electric appliance, in particular hob (11), with a display operating mask (13) or cover, characterized in that, below the display operating mask (13) or cover, a display device (18) according to any of the claims 9 to 11 is disposed, wherein preferably the display device rests on a bottom side (14) of the display operating mask (13) or cover.

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