DE102022131597A1 - Display device with coated reflective surface for displaying information - Google Patents

Abstract

The invention relates to a display device (1) for displaying information, comprising an optical body (30) and a primary display element (10) which is designed to emit light for displaying information and to couple it into the optical body (30) at a first plane (31), wherein the optical body (30) is designed to reflect the coupled-in light for displaying information for a viewer (B) at a reflection surface (36) arranged in a third plane (33) and to redirect it to a second plane (32), and wherein the reflection surface (36) of the optical body (30) is provided with at least one coating (38) for reflecting the light.

Description

The invention relates to a display device with a coated reflective surface for displaying information, in particular in a motor vehicle.

A variety of display devices are known from the state of the art, which are based on different functional principles.

It is also known to couple the light generated by a display or a display element into an adjacent optical body, to redirect it in the optical body and thus to make it visible to the viewer.

Because the light is redirected in the optical body, the viewer no longer looks directly at the display, but only at the aesthetically pleasing optical body in which the light is directed or reflected in a targeted manner.

The problem here, however, is that when the light is directed or reflected in the optical body, light may be scattered or may escape from the optical body at unwanted surfaces, or the light coupled in for information display may not be directed exclusively in the specified direction.

It is also possible that at certain viewing angles the viewer does not look at the light directed by the optical body, but at light that emerges from a surface of the optical body that is not intended for display. In addition, such light or the image produced by it is not redirected in the optical body as intended, so that the image perceived by the viewer through the light is distorted or mirror-inverted and in any case negative for the readability of the display device.

The invention is therefore based on the object of overcoming the aforementioned disadvantages and providing a display device on which a viewer looking at the optical body can perceive an image or information essentially exclusively in the intended manner.

This object is achieved by the combination of features according to patent claim 1.

According to the invention, a display device for displaying information, in particular in a motor vehicle, is therefore proposed. The display device has an optical body and a primary display element, which can be, for example, a display with background lighting or another suitable coupling source. The display device is designed to emit light for displaying information or generally for image generation and to couple it into the optical body at a first level, in particular at a coupling surface of the optical body located in the first level. The optical body is also designed to reflect the coupled-in light for displaying information for an observer at a reflection surface arranged in a third level and to redirect it to a second level, i.e. in particular to reflect it, the second level being oblique to the first level. This means that the observer can detect the light coupled in by the primary display element in the first level and read the information by looking at the second level or at a display surface mentioned below. The invention provides that the reflection surface of the optical body is provided with at least one coating to reflect the light.

It is fundamentally clear that in conventional designs, too little of the light coupled into the optical body at the first level is reflected at the reflective surface, which means that the image generated in the second level or on the display surface is often darker or too dark. Furthermore, the non-reflected light can exit the optical body at the third level, in which the reflective surface runs, and thus be perceived by the viewer in an unwanted way.

The fact that the light is not completely reflected is often due to the fact that the reflection surface or the second plane in which it lies has an angle of approximately 40 to 50° compared to the incident light coupled into the first plane and, depending on the material chosen for the optical body, complete total reflection is not yet possible. However, such an angle is necessary or at least advantageous for the information display.

In summary, according to the invention, it is therefore proposed to provide an additional coating or layer to improve the reflection properties of the reflection surface.

According to an advantageous development, it is provided that the coating has at least one layer of a metal, in particular of aluminum or silver. If the coating has several layers, it is preferably provided that at least one of the layers is made of a metal.

Furthermore, the reflection surface of the optical body for reflecting the light can be coated with several, in particular alternating, layers to form the coating, which form an optical resonator. The alternating layers or the resonator formed thereby is designed to shift the reflected light relative to the incident light by a phase of λ/2 or a multiple of λ/2.

At least part of the layers forming the optical resonator may be made of indium tin oxide (ITO).

The coating or the at least one layer which forms the coating is particularly preferably vapor-deposited, so that correspondingly low layer thicknesses can be achieved.

The optical body is preferably an optical crystal, i.e. rigid. This also makes it possible for the optical body or optical crystal to only be embedded in a carrier in the area of the first plane and to be essentially free on its other sides.

If the display device is integrated, for example, into a steering handle of a motor vehicle, a side of the optical body forming the first plane can be embedded in a steering rim or handle section of the steering handle, so that the optical body can protrude from the steering rim or handle section. Of course, the optical body can still be covered by design or functional elements, such as films or the like, although these do not have a supporting or load-bearing function for the optical body.

The optical body can have a coupling surface in the first plane, at which the light is coupled into the optical body. Furthermore, the optical body can additionally or alternatively have a display surface in the second plane, at which the light is projected for information display. This display surface can additionally be provided with an anti-glare and/or anti-reflective coating in order to improve the quality or contrast of an image visible on the display surface and thereby the display or readability on the display surface. Additionally or alternatively, the optical body can have the reflection surface in a third plane, at which the light coming from the first plane is deflected to the second plane, and wherein the third plane is arranged at an angle of 20° to 70°, in particular 40° to 50° and further in particular 45° with respect to the light coming from the first plane, i.e. running in the main direction, incident on the third plane.

In addition, the display device can have a secondary display element, which is preferably arranged adjacent to the third plane and is designed to emit light for information display and to couple it into the optical body.

The secondary display element can be designed to couple light into the optical body orthogonally to the second plane or to the display surface and in particular at the reflection surface. For this purpose, the coating provided on the reflection surface can be designed to be translucent on one side.

A display provided on the display surface can accordingly be provided jointly by the primary display element and the secondary display element, wherein the images and/or information generated by the first display element and the second display element via the respectively coupled-in light for generating the display on the display surface can be arranged next to one another and/or can at least partially superimpose one another.

Furthermore, it can be provided that a directing element is connected upstream of the optical body, which is designed to direct the light emitted by the primary display element in a main direction before it is coupled into the optical body, so that the scattered light components of the coupled-in light are eliminated or reduced or the scattered light components are aligned in the main direction.

The main direction is understood to mean in particular a direction orthogonal to the first plane. Alternatively, the main direction can also be defined as corresponding to a direction which, reflected at the third plane explained later, runs orthogonally to the second plane.

By directing or aligning the light, the angle of illumination in the main direction is restricted so that the light propagating in the main direction can be redirected as intended in the optical body. Accordingly, when looking directly at the primary display element, the viewer sees no light or at least reduced light.

An advantageous further development provides that the straightening element is at least a single-layer film and in particular made of plastic. In particular, it can be a film made of PMMA with at least one layer.

In addition, the directing element can form optical structures for directing the light, which limit an optical illumination angle of the light emitted by the primary display element in the main direction.

The optical structures can be line lenses and/or prism structures and/or, in particular, light barriers or lamellae created by a laser, which absorb light outside the main direction and/or direct it in the main direction. Because the scattered light components of the light are directed in the main direction, the brightness of the light in the main direction is also increased.

Furthermore, the directing element can be multi-layered, wherein a layer having the optical structures is arranged between two transparent layers, which are covered on their respective side facing away from the optical structures in particular by a protective layer.

The layer having the optical structures can, for example, be a lamella layer and thus have the light barriers. The lamellas or the light barriers can in particular be made of acrylic resins and/or carbon black.

The two transparent layers, between which the layer having the optical structures is arranged, can be made of polycarbonate, for example.

The protective layers that cover the transparent layers can be matt or glossy and can provide or form abrasion protection.

The transparent layers in particular have a thickness of between 100 and 150 µm and preferably 125 µm. The lamella layer further preferably has a thickness of between 100 and 300 µm and in particular 200 µm.

The distance between the individual lamellae or light barriers running parallel to one another in the lamella layer is preferably between 50 and 100 µm and in particular 72 µm, wherein the lamellae themselves have, for example, a thickness of less than 5 µm and are furthermore in particular 1 µm thick.

Additional layers, such as connecting layers between the lamella layer and the transparent layers as well as the protective layer, can have a very small and therefore negligible thickness.

The total thickness of the straightening element, i.e. the extension in the main direction, is preferably less than 1 mm and in particular in a range of 0.4 to 0.7 mm, in particular 0.53 mm.

The directing element can be arranged between the primary display element and the optical body. Alternatively, the primary display element can have a backlight, a display, and the directing element, wherein the directing element is arranged after the backlight and before or after the display.

The features disclosed above can be combined as desired, as long as this is technically possible and they do not contradict each other.

• 1 eine Lenkhandhabe eines Kraftfahrzeugs mit zwei darin integrierten Anzeigevorrichtungen;
• 2 eine herkömmliche Anzeigevorrichtung;
• 3 eine erste Variante einer erfindungsgemäßen Anzeigevorrichtung;
• 4 eine zweite Variante einer erfindungsgemäßen Anzeigevorrichtung.

Other advantageous developments of the invention are characterized in the subclaims or are described in more detail below together with the description of the preferred embodiment of the invention with reference to the figures. They show:

• 1 a steering handle of a motor vehicle with two display devices integrated therein;
• 2 a conventional display device;
• 3 a first variant of a display device according to the invention;
• 4 a second variant of a display device according to the invention.

The figures are schematic examples. Identical reference symbols in the figures indicate identical functional and/or structural features.

For a better overview, 1 a steering handle 2 of a motor vehicle is shown, in which two display devices 1 are integrated. Referring to the 2 , 3 and 4 explained structure, the primary display element 10 is embedded in the circumferential steering rim 50 of the steering handle 2, wherein the optical body 30 projects radially inward from the steering rim and is essentially free of further support elements.

To illustrate the problem, 2 a display device 1 without the coating 38 according to the invention is shown. The primary display element 10 couples light or the image generated thereby to the first plane 31 of the optical body or the optical crystal 30 into it, wherein the first light L1 coupled in along the main direction A is only partially reflected at the reflection surface 36 in the third plane 33. Due to the lack of total reflection at the third plane 33, a further part of the coupled-in light exits the optical crystal 30 as a second light L2, which can be perceived by a viewer B in an unintended manner.

Because the second light L2 may not be reflected or guided in the optical crystal 30 or may be reflected or guided incorrectly and exit the optical body 30 in a plane not intended for it, it may happen that the observer B can see the second light L2 in certain positions, so that he perceives a distorted and unwanted image.

Since it is intended that the light L1 for information display is reflected exactly once in the optical crystal 30 and specifically at the third plane and thus mirrored, the light received by the observer B in 2 captured image, for example, upside down.

To avoid such a faulty image, as in 3 shown - a coating 38 of the optical body 30 or the optical crystal 30 is provided on the third plane 33. In the present case, this coating 38 consists of a vapor-deposited metal, which improves the reflection of the light L1 striking the reflection surface 36 from the main direction A and essentially completely reflects it. This not only prevents the light from escaping from a surface or plane not intended for it, but at the same time increases the brightness of the light striking the second plane 32 or the display surface 35.

The light or an image generated thereby is coupled into the optical crystal 30 by the primary display element 10 at the first level 31 or at the coupling surface 34 provided in the first level 31, is essentially completely reflected at the third level 33 or the reflection surface 36 provided there and is thereby directed to the second level 32 or onto the display surface 35 provided there, so that a viewer B can correctly read and perceive the image generated by the light L1 or the information generated by the light L1.

Furthermore, a veneer 51 covering the optical crystal 30 from the primary display element 10 can be provided, so that an edge of the optical crystal 30 formed at the intersection line of the first plane 31 and the second plane 32 and preferably also the primary display element 10 are not visible to the observer B.

In 4 is a variant according to 3 shown, wherein an additional coating 37 and a directing element 40 arranged upstream of the first plane 31 are provided on the second plane 32, by means of which light otherwise coupled into the optical body 30 outside the main direction A or obliquely to the main direction A is deflected or absorbed in the main direction A. The coating 37 is provided as an anti-glare and/or anti-reflection coating, in particular completely covering the display surface 35, in order to increase the quality or the contrast of the image.

To supplement the display, secondary display elements 20, 21 can also be provided, which can be arranged alternatively to one another or together on a side of the optical crystal 30 opposite the second plane 32. These can couple a light L3, L4 orthogonally to the main direction or to the second plane 32 into the optical body 30, by means of which an image can be generated on the display surface 35, which overlays and/or supplements the image generated by the primary display element 10 on the display surface 35.

Thus, the light L4 coupled in by the secondary display element 20 is intended to expand the image generated by the primary display element 10 so that the image generated for the viewer B becomes larger.

In contrast, light L3 coupled into the secondary display element 21 is intended to superimpose the image generated by the primary display element 10, so that the superimposed images together form an information display for the viewer.

Claims (10)

Display device (1) for displaying information, comprising an optical body (30) and a primary display element (10) which is designed to emit light for displaying information and to couple it into the optical body (30) at a first plane (31), wherein the optical body (30) is designed to reflect the coupled-in light for displaying information for a viewer (B) at a reflection surface (36) arranged in a third plane (33) and to redirect it to a second plane (32), characterized in that the reflection surface (36) of the optical body (30) is provided with at least one coating (38) for reflecting the light. Display device according to Claim 1 , wherein the coating (38) is or has at least one layer of a metal. Display device according to Claim 1 or 2 , wherein the reflection surface (36) of the optical body (30) is coated with several layers for reflecting the light and for forming the coating (38), which form an optical resonator which is designed to shift the reflected light relative to the incident light by a phase of λ/2 or a multiple of λ/2. Display device according to the preceding claim, wherein at least a part of the layers forming the optical resonator are formed from indium tin oxide. Display device according to one of the preceding claims, wherein the coating (38) is vapor-deposited. Display device according to one of the preceding claims, wherein the optical body (30) is an optical crystal. Display device according to one of the preceding claims, wherein the optical body (30) has a coupling surface (34) in the first plane (31), at which the light is coupled into the optical body (30), and/or wherein the optical body (30) has a display surface (35) in the second plane (32), at which the light is projected for information display, and/or wherein the light coming from the first plane (31) is deflected at the third plane (33) to the second plane (32), and wherein the third plane (33) is arranged at an angle of 20° to 70° with respect to the incident light coming from the first plane (31). Display device according to one of the preceding claims, further comprising a secondary display element (20, 21) which is designed to emit light for information display and to couple it into the optical body (30). Display device according to the two preceding claims, wherein the secondary display element (20, 21) is designed to couple light orthogonal to the display surface (35) into the optical body (30). Display device according to one of the preceding claims, wherein a directing element (40) is connected upstream of the optical body (30), which is designed to direct the light emitted by the primary display element (10) in a main direction (A) before coupling into the optical body (30).

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