Display device with coated reflecting surface for displaying information

Abstract

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

Description

[0001] Marquardt GmbH

[0002] P 092 PCT

[0003] Display device with coated reflective surface for displaying information

[0004] Description:

[0005] The invention relates to a display device with a coated reflective surface for displaying information, in particular in a motor vehicle.

[0006] A variety of display devices based on various operating principles are known from the prior art. It is also known to couple the light generated by a display or display element into an adjacent optical body, redirect it within the optical body, and thereby make it visible to the viewer.

[0007] 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 specifically directed or reflected.

[0008] The problem, however, is that when the light is directed or reflected in the optical body, light can be scattered or the light can escape from the optical body at unwanted surfaces, or the light coupled in for information display cannot be directed exclusively in the specified direction.

[0009] Furthermore, it is possible that, at certain viewing angles, the viewer does not see the light directed by the optical body, but rather light emerging from a surface of the optical body not intended for display. In addition, such light, or the image created by it, may not have been redirected as intended within the optical body, so that the image perceived by the viewer through the light is distorted or mirror-inverted, and in any case, adversely affects the readability of the display device.

[0010] The invention is therefore based on the object of overcoming the aforementioned disadvantages and of 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.

[0011] This problem is solved by the combination of features according to patent claim 1.

[0012] 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 backlighting 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 plane, in particular at a coupling surface of the optical body lying in the first plane. Furthermore, the optical body is designed to reflect the coupled-in light for displaying information for a viewer at a reflection surface arranged in a third plane and to redirect it to a second plane, i.e. in particular to reflect it, wherein the second plane is oblique to the first plane.This means that the viewer can detect the light coupled in by the primary display element in the first plane and read the information by looking at the second plane or at a display surface mentioned below. According to the invention, the reflective surface of the optical body is provided with at least one coating to reflect the light.

[0013] Fundamentally, it should be noted that in conventional designs, too little of the light coupled into the optical body at the first level is reflected by the reflective surface, which often results in the image generated in the second level or on the display surface being darker or too dark. Furthermore, the non-reflected light can escape from the optical body at the third level, where the reflective surface runs, and thus be undesirably perceived by the viewer.

[0014] The fact that the light is not completely reflected is often due to the fact that the reflecting surface, or the second plane in which it lies, forms an angle of approximately 40 to 50° relative to the incident light coupled into the first plane. Depending on the material chosen for the optical body, total internal reflection is not yet possible. However, such an angle is necessary or at least advantageous for the information display.

[0015] In summary, the invention proposes to provide an additional coating or layer to improve the reflection properties of the reflection surface.

[0016] According to an advantageous development, the coating comprises at least one layer made of a metal, in particular aluminum or silver. If the coating comprises multiple layers, it is preferably provided that at least one of the layers is formed from a metal.

[0017] Furthermore, the reflective surface of the optical body can be coated with several, in particular alternating, layers to reflect the light to form the coating, forming an optical resonator. The alternating layers or the resonator formed thereby are designed to shift the reflected light relative to the incident light by a phase of λ / 2 or a multiple of λ / 2.

[0018] At least part of the layers forming the optical resonator may be made of indium tin oxide (ITO).

[0019] The coating or the at least one layer forming the coating is particularly preferably vapor-deposited, so that correspondingly small layer thicknesses can be achieved.

[0020] The optical body is preferably an optical crystal, i.e. rigid. This also makes it possible for the optical body or the optical crystal to be embedded in a carrier only in the region of the first plane and to be essentially free on its other sides. If the display device is integrated, for example, in 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 grip section of the steering handle, such that the optical body can protrude relative to the steering rim or grip 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 carrying function for the optical body.

[0021] 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-reflection coating in order to improve the quality or the contrast of an image visible on the display surface and thereby the display or the 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 at an angle of 20° to 70°, in particular 40° to 50° and further in particular 45° relative to the light coming from the first plane, ielight incident on the third plane in the main direction.

[0022] Additionally, the display device can have a secondary display element, which is preferably arranged adjacent to the third plane and configured to emit light for information display and to couple it into the optical body. The secondary display element can be configured to couple light into the optical body orthogonally to the second plane or to the display surface, and in particular at the reflective surface. For this purpose, the coating provided on the reflective surface can be designed to be translucent on one side.

[0023] 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 can be arranged next to one another to generate the display on the display surface and / or can at least partially superimpose one another.

[0024] Furthermore, it can be provided that a directing element is connected upstream of the optical body, which directs the light emitted by the primary display element in a main direction before coupling 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.

[0025] The principal direction is understood in particular to be a direction orthogonal to the first plane. Alternatively, the principal direction can also be defined as a direction that, reflected at the third plane (explained further below), is orthogonal to the second plane.

[0026] By directing or aligning the light, the illumination angle 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 perceives no or at least a reduced amount of light. An advantageous development provides for the directing element to be a film with at least a single layer, in particular made of plastic. Furthermore, it can be a film with at least a single layer made of PMMA.

[0027] 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.

[0028] The optical structures can be linear lenses and / or prism structures and / or, in particular, laser-generated light barriers or lamellae that absorb light outside the main direction and / or direct it into the main direction. By directing the scattered light components into the main direction, the brightness of the light in the main direction is simultaneously increased.

[0029] Furthermore, the directing element can be multi-layered, wherein a layer having the optical structures is arranged between two transparent layers which are covered in particular by a protective layer on their respective sides facing away from the optical structures.

[0030] The layer containing the optical structures can, for example, be a lamella layer and thus contain the light barriers. The lamellae or light barriers can be formed, in particular, from acrylic resins and / or carbon black.

[0031] The two transparent layers between which the layer having the optical structures is arranged can be made of polycarbonate, for example.

[0032] The protective layers covering the transparent layers can be matte or glossy and can provide or form abrasion protection. The transparent layers preferably have a thickness between 100 and 150 μm, and preferably 125 μm. The lamella layer further preferably has a thickness between 100 and 300 μm, and in particular 200 μm.

[0033] The distance between the individual lamellae or light barriers running parallel to one another in the lamella layer is preferably between 50 and 100 pm and in particular 72 pm, wherein the lamellae themselves have, for example, a thickness of less than 5 pm and are furthermore in particular 1 pm thick.

[0034] Further layers and, for example, 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.

[0035] The total thickness of the straightening element, ie 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.

[0036] The directing element can be arranged between the primary display element and the optical body. Alternatively, the primary display element can comprise a backlight, a display, and the directing element, wherein the directing element is arranged after the backlight and before or after the display.

[0037] The features disclosed above can be combined as desired, as long as this is technically possible and they do not contradict each other.

[0038] Other advantageous developments of the invention are characterized in the subclaims or are presented in more detail below, together with the description of the preferred embodiment of the invention, with reference to the figures. They show: Fig. 1 a steering handle of a motor vehicle with two display devices integrated therein;

[0039] Fig. 2 shows a conventional display device;

[0040] Fig. 3 shows a first variant of a display device according to the invention;

[0041] Fig. 4 shows a second variant of a display device according to the invention.

[0042] The figures are schematic examples. Identical reference numerals in the figures indicate identical functional and / or structural features.

[0043] For the sake of clarity, Figure 1 depicts a steering handle 2 of a motor vehicle into which two display devices 1 are integrated. Referring to the structure explained with Figures 2, 3, and 4, the primary display element 10 is embedded in the circumferential steering rim 50 of the steering handle 2, with the optical body 30 projecting radially inward from the steering rim and being essentially free of further support elements.

[0044] To illustrate the problem, Figure 2 shows a display device 1 without the coating 38 according to the invention. The primary display element 10 couples light or the image generated thereby into the first plane 31 of the optical body or optical crystal 30, 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 portion 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 may be reflected incorrectly in the optical crystal 30,and exits the optical body 30 in a plane not intended for it, it can happen that the observer B can see the second light L2 in certain positions, so that he perceives a distorted and unwanted image.

[0045] 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 is thus mirrored, the image captured by the viewer B in Figure 2 is, for example, upside down.

[0046] To prevent such an erroneous image, a coating 38 of the optical body 30 or the optical crystal 30 is provided on the third plane 33, as shown in Figure 3. This coating 38 consists in this case 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 reflects it completely. This not only prevents the light from escaping onto a surface or plane not intended for this purpose, but also increases the brightness of the light striking the second plane 32 or the display surface 35.

[0047] The light or an image generated thereby is coupled by the primary display element 10 into the optical crystal 30 at the first plane 31 or at the coupling surface 34 provided in the first plane 31, is essentially completely reflected at the third plane 33 or the reflection surface 36 provided there, and is thereby directed to the second plane 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 can be provided that covers the optical crystal 30 from the primary display element 10, 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, is not visible to the viewer B.

[0048] Figure 4 shows a variant according to Figure 3, 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 directing element 40 light otherwise coupled into the optical body 30 outside the main direction A or obliquely to the main direction A is deflected or absorbed into 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 contrast of the image.

[0049] 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 image overlays and / or supplements the image generated by the primary display element 10 on the display surface 35.

[0050] 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.

[0051] On the other hand, the secondary display element 21 is coupled

[0052] Light L3 is provided 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

Patent claims 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 made of a metal.The display device according to claim 1 or 2, wherein the reflection surface (36) of the optical body (30) is coated with multiple layers for reflecting the light and for forming the coating (38), which layers form an optical resonator configured to shift the reflected light relative to the incident light by a phase of λ / 2 or a multiple of λ / 2. The display device according to the preceding claim, wherein at least some of the layers forming the optical resonator are made of indium tin oxide. The 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 displaying information 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) before it is coupled into the optical body. Body (30) in a main direction (A).

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