DE102012005510B4 - Disc and method for producing a disc for a display unit of a head-up display - Google Patents

Abstract

A disk (5) for a display unit (4) of a head-up display wherein,
- The light beams (8) are projected onto the pane (5) to generate image information to be displayed,
- The disc (5) is arranged in the field of view of an observer (1)
- and the disc (5) has a partially reflective coating,
- That the disc (5) of the display unit (4) has a delimiting edge (16) and the edge (16) corresponds to part of an edge region (15) of the disc (5), characterized in that,
- That the edge area (15) of the disc (5) is at least partially provided with a structure (18),
- That the edge region (15) of the disk (5) is delimited by essentially plane-parallel disk surfaces (13, 14) of the disk (5),
- That the edge region (15) between the essentially plane-parallel disk surfaces (13, 14) of the disk (5) is asymmetrically convex.

Description

The present invention relates to a pane for a display unit of a head-up display with the features of the preamble of claim 1. The invention also relates to a head-up display equipped with such a pane.

There are display units of head-up displays known in which panes made of glass or plastic are used to display information. Such head-up displays are used, for example, in vehicles, aircraft or in helmets or glasses, in which relevant data or image information is used to support a driver, pilot or other person.
The data or image information to be displayed is projected onto the pane via a display / display, the pane being in the direct field of vision of the observer, in this case the driver, pilot or other person. The aim of this indirect display located in the field of view is to support the viewer so that he does not have to turn his gaze or his head from his actual viewing direction and can therefore turn his full attention to the control of a vehicle, aircraft or the like. The panes of the display units of the head-up displays can, as already mentioned, be made of both glass and plastic, in both cases the panes are mirrored in a semi-transparent manner so that the viewer can look through them to their actual field of observation.

The requirements for such panes of such display units can be diverse, these often being designed with multiple curves and the geometry of the pane being adapted to the surrounding boundary conditions.

Therefore, such disks are now preferably designed as plastic disks. The optical quality required here corresponds to the requirements of the application cases or areas of use, with the manufacturing processes used in production requiring considerable know-how and experience, especially in the use and processing of the different plastics used. For example, in order to maintain the optical quality and the specified shape, it is extremely important that inclusions, stresses in the material and distortion of the molded parts are avoided during the manufacturing process. As a customary manufacturing process for this purpose, the injection molding process is used, for example, for the manufacture of optical plastic parts, with particular attention being paid to the injection molding tools used. In the case of visually high-quality components, these injection molding tools are of particular execution quality and quality, whereby in particular thermal influences, tool separations and possible movements of tool halves as well as slides present in the tool must be taken into account. Here it is of the utmost importance that the tool halves and tool slides do not leave any traces, impressions or damage on the workpiece when the mold is opened.

Such know-how in the design and use of injection molding tools using suitable plastics to be injected is described in detail in the trade journal “Photonik”, issue 4/2008 with the title “Plastic optics for industrial precision applications”, author Dr Thomas Luce, Erik Schalle, of Eschenbach-Optik-GmbH Nuremberg, has been extensively described. Here, the difficulties of the plastic to be injected, preferably a polymethyl methacrylate or a polycarbonate, are discussed in particular, with the difficulties in maintaining the precise predetermined shape and the possible parameters that can be influenced by this shape being discussed in detail. In particular, the influence of the temperatures of the plastic to be injected, as well as the temperature behavior of the injection molding tools, is explained here. In addition, it is reported that the injection speed as well as the injection openings and channels for filling the mold are of great importance for tension-free, flawless shape design and that reliable handling enables the manufacture of flawless workpieces solely through the interaction of development and production.

In another report in the magazine “Kunststoffe” in the 5/2007 issue of Karl Hanser Verlag, Munich, an article entitled “The transparent internal printing” is dealt with under the heading “Injection Molding”. As already described, the know-how of the injection molding tools is of great importance. In the present article, the measurement of the mold cavity pressure in the production of optical components without influences, for example mechanical influences, on the workpiece is presented. This non-contact measurement of the constant internal pressure during the manufacturing process has a decisive influence on the quality of the workpiece to be manufactured during the injection molding process. Here, too, it becomes clear that in manufacturing processes such as injection molding or injection compression molding, considerable, unforeseeable influences must be taken into account, which are explained using an example.

In another publication by Karl Hanser Verlag Munich in the magazine “KU Kunststoffe ", Volume 91 (2001), the production of highly transparent optical molded parts is described in a report" Perspective in injection molding ". Such highly transparent optical molded parts include lenses, as well as the plastic pane of a head-up display described in the title. In specially developed embossing processes, special quality requirements in terms of shape and surface quality can be represented on the optical, highly transparent molded parts. The present article relates, for example, to lenses, glasses, optical data carriers, displays, computer screens, headlights, lenses, automobile windows and other optical components, these components realizing highly effective anti-reflective coatings on their optical surfaces during injection molding or embossing of micro- or nanostructures permit. Special holding means can also be attached in one piece to the optical components for fixing or positioning the optical components in further structural units during the manufacturing process. It is also possible for different optical contours / structures to be formed on the optical molded parts, which can fulfill several different functions at the same time during actual operation.

In the DE 103 03 240 B4 describes a display unit arranged in a vehicle with a combiner. This essentially shows the layer structure of a partially translucent reflection or polarization part, which is applied overall as a one-piece insert on a plastic base (pane) and encapsulated with the plastic base. In particular, the reflective layer is protected from moisture and damage through the use of several layers arranged one above the other and the cast-in position in the combiner.

Via a display arranged in the vehicle, from which an image is projected onto the combiner and thus onto the plastic base with reflection or polarization part, the projected image is displayed as a virtual image for the driver in accordance with the reflection or polarization parts . The plastic base (disc) itself is made of a transparent plastic. In the case of the layers arranged within the combiner and their boundaries lying within the combiner / plastic base, their boundaries are printed on at least one side of the layers with a gradation layer having increasing or decreasing intensity. This serves to evenly conceal the transition between the layers and the combiner / plastic base, the edge line between two different transparent sections. The gradation can be made up of dot-like structures here, for example. The printed gradation layer is preferably located between the plastic base and the reflection or polarization part.

In the US 2010 0 066 645 A1 it is a clearly visible head-up display in which a head-up display unit outputs image information by means of a display lamp, which image information is generated in an area near a windshield as a virtual image on the basis of reflected light / image information and thus information is made available to the driver.

The windshield is a vehicle windshield which, independently of the area that is reflective for the image information, has a masking in the flat area that extends up to the edge area of the windshield. The masked area of the front panel is designed all around as a narrow masking close to the edge, with an area of the masking part having an enlarged area in the lower middle masking area of the front panel. The reflective area for displaying the image information is also provided in this area.

For this purpose, the masking is applied directly to the side of the vehicle windshield facing the vehicle interior or between two plane-parallel glass panes that are laminated to one another by adhesive bonding. Here, the masking is applied, for example, to the inside of the first / outer pane of glass. An adhesive coating which is applied to this inner side of the first / outer glass pane with the masking is then used for lamination with a second / inner glass pane. As already mentioned, this enlarged area, provided both with a reflective coating and with the masking, can serve as a display for displaying the image information.

The masking is formed, for example, by rows of dark or black dots of different sizes, this masking being applied exclusively to the flat area of the vehicle windshield. This head-up display is therefore not formed by an additional, separate pane that represents image information, but is integrated directly into or on the vehicle windshield.

From the U.S. 5,781,345 A a manufacturing method for manufacturing a graduated dielectric combiner for a head-up display is known. The head-up display is made up of two plane-parallel combiners (panes), these two combinators at least partially overlapping, so that light beams from an image-generating unit are used to generate the Image information is projected onto both combiners and can be perceived by the eye of the beholder. The superimposing increases the display area significantly, with the superimposed areas of both combiners having a large number of mutually graded different coating intensities, so-called bands. The specified percentage of each tape contains the specified number of dielectric coatings, so that the layers of the overlapping panes with their dielectric coating, viewed in percentage, together give the maximum coverage of the non-overlapping areas of the panes.

For the viewing eye, there is thus an overlapping area of the two panes, with the light / image information emitted by the projection unit becoming visible / recognizable within the overlapping area. The light emitted by the CRT is permeable to the “light wavelengths” of visible light in the non-overlapping area, i.e. the individual pane itself, whereas the dielectric layers reflect light of a predetermined wavelength (light emitted by the CRT) and others that differ from this Let wavelengths through. Image information is thus generated for the head-up display. The essential core of this invention therefore lies in the overlapping panes and their dielectric coatings, which are combined in mutual dependence in such a way that a 100% coating is present in the overlapping area.

the US 2009/0295681 A1 shows a head-up display which essentially consists of two flat panes spaced in parallel, for example a windshield of a vehicle. A transparent plastic layer is placed between the two panes. In the contact area of the plastic layer with the two panes, a matt black material can be applied at least in some areas that can be positioned on each side of the respective pane that is in contact with the plastic layer.

Light rays emitted by an image source are reflected on the surface of the inner pane facing the vehicle interior, creating a virtual image. Light rays that hit the matt black material, on the other hand, are not transmitted any further. This avoids reflections, falsifications or so-called ghost images. The matt black material and other coatings are applied exclusively to the flat, parallel areas of the panes and are limited to the field of vision of the observer.

Furthermore, a rough, matt black layer can also be applied to the outer surfaces of the two panes, which, viewed from the outside as well as from the inside of the vehicle, delimit an image area and / or can absorb light rays. The matt black layers can have stepped structures, these stepped matt black areas usually being provided in the flat outer area of the windshield. The matt black material can, for example, consist of lead or chrome-based ceramic ink and is applied using the screen printing process.

In the US 7 397 606 B1 describes a head-up display for road vehicles and / or aircraft, in which the head-up display is formed by a separate window that is independent of cabs or vehicle windows. The disk consists of one or more individual disks, it being possible for the individual disks to be shaped as lenses. The individual panes / lenses can be made completely different in terms of their curvatures and optical characteristics. Furthermore, however, it is also possible for the panes / lenses to be able to represent panes / lenses arranged in a symmetrical mirror image. In the area of the merging, that is to say the area where the panes / lenses are joined to one another in a touching manner, these identical shapes or lenses have geometries. These disks / lenses are so-called miniscus lenses, which have a concave and a convex side, but the curvatures of both sides are designed to be the same. These meniscus lenses are designed in such a way that their curvatures and optical characteristics can compensate for distortions or other optical disturbances in such a way that the viewer can see a complete and undisturbed image on the head-up display. These disks / lenses (miniscus sections) assembled in this way inherit the display element of the head-up display as a whole. In the case of the meniscus lenses, it is preferable to use symmetrical aspherical meniscus lenses. Each lens is therefore non-symmetrical, aspherical, ie contains non-spherical optical surfaces. The meniscus sections can also have a multilayer dichroic coating on a first surface, with an anti-reflective coating being applied to a second, opposite surface. Both coatings follow the respective surfaces of the meniscus sections or the assembled disk / lens in parallel. The assembled pane / lens determines the field of vision by its predetermined extent, provided it is at a predetermined distance from the viewer / operator.

In summary, the US 7 397 606 B1 Essentially the curvatures and the radii of curvature of the meniscus lens as the main claim, the coatings of the meniscus lens also belonging to it.

the US 6 612 840 B1 relates to a vehicle simulation system for simulating a vehicle for a human user, the system comprising an image system which generates a visual image visible to a user on a screen. The image contains a scene representing a simulated view / display image outside the vehicle and head-up, this scene being superimposed on a combiner structure through which the user can see. The combiner structure is positioned so that the image with the heads-up display image can be viewed continuously by the user. In the vehicle simulation system, a filter structure similar to the combiner is positioned laterally outside the combiner structure, so that during operation, based on the position of the user, the user can also view the scene through the filter structure.

An image of the outside environment is projected on a screen. The head-up display is switched in front of it accordingly. The viewer looks through the head-up display to see the "surroundings" and the corresponding information such as. B. Symbols or data shown. The head-up display has a filter (as described above) which only allows certain wavelengths of light to pass through, so that both the symbols in the head-up display and the image of the surroundings projected onto the screen can be recognized. If there is a head-up display symbol to be displayed, the filter structure is impermeable to light in these areas. The head-up display is transparent so that the viewer can look out of the vehicle unhindered. The projection of the environment and that of the information are combined in such a way that the viewer can recognize an image.

The structure of the head-up display comprises a transparent central section which is accommodated in a frame mounted on the simulator cockpit. The frame has two lateral lateral sides and an upper edge, the lateral sides with their free lower ends being received in the simulator cockpit. There is also a lateral filter structure, which is also provided as a narrow band above the frame. The distance between the lateral sections is half the average interpupillary distance of a viewer, i.e. H. the average displacement of each eye of a human observer from the center between the eyes and is therefore suitable for use with the head-up display simulator to prevent visual defects. This binocular problem is completely eliminated by the filter structure. The head-up display simulation is quickly projected periodically.

In the JP 2009 292 223 A it is essentially a vehicle warning display device. A heads-up display is arranged approximately parallel to the windshield. The head-up display is transparent to the driver's line of sight. Above the upper limit of the head-up display, there is a reflective area on the inside of the windshield. At the lower end of the head-up display, a light source (warning light source) is arranged on the front side (pane thickness of the head-up display), which emits a light signal in the event of a dangerous situation. Here, the light signal is emitted through the head-up display to its upper end, with the head-up display (pane) functioning as a light guide. At its upper end (in the area of the windshield thickness) the head-up display is designed in a narrowly limited area in such a way (geometry, satined surface) that the light emitted by the head-up display onto the reflective layer of the windshield is reflected and thus the warning is recognizable for the driver. The upper end of the head-up display (pane) is designed, at least in some areas, as optics that couple out light. Light should be emitted from the head-up display in a targeted manner. For this purpose, the edge of the head-up display (pane) is designed or structured in such a way that the light radiated through the pane can only be coupled out at this one point. At the upper end of the pane, only the area is satined or provided with an optic, which is absolutely necessary for the light extraction and for the warning display on the reflective layer of the windshield.

The present invention deals with the problem of specifying an improved embodiment for a plastic pane of a display unit, which is characterized in particular by the fact that scattered light is to be avoided in the edge region of the pane and the pane is to be produced comparatively simply, quickly and inexpensively by means of an injection molding process is.

According to the invention, this problem is solved by the subjects of the independent claims. Advantageous embodiments are the subject of the dependent claims.

The invention is based on the general idea of adding to a pane for a display unit of a head-up display an optical function expanded to the actual purpose of the pane. For this purpose, the edge area of the pane is at least partially designed in such a way that that light introduced into the pane to generate data information or image information cannot be perceived as scattered light in the edge area of the pane.

The problem to be solved here is based on the fact that light rays from a light source through a display unit / display in which the information for the pane is provided can generate light reflections at least partially within the pane when they enter the pane. These light reflections can be reflected multiple times by the essentially plane-parallel surfaces of the pane, reaching the edge area of the pane, where they can then exit the pane again, creating a light effect of the pane in the direction of the viewer, or for someone from the outside into the Viewers looking into the pane create a perceptible, quasi-illuminated edge area. This disturbs and distracts the viewer considerably from his actual task, which is why the special design of the edge area of the pane is intended to prevent such light reflection.
Such panes for display units of a head-up display are generally provided with several different thin coatings, at least one coating being a partially reflective coating. Even this partially reflective coating, which is not only applied to the flat configurations of the pane, but also at least partially encompasses the edge area, does not prevent the light reflections described above from occurring in the edge area of the pane.

In the current procedure, when manufacturing such panes, they are produced in several work steps, a major work step being mechanical reworking of the edge. For this purpose, the edge is often mechanically reworked, for example, by a milling process, with a certain roughness of the milled edge area being created. When using such mechanically reworked panes, the previously described light reflections in the edge area (emerging light in the edge area) can be reduced considerably. It turns out, however, that this manufacturing process in several work steps with mechanical post-treatment is very time-consuming and labor-intensive, the error rate of workpieces produced in this way being not insignificant. The wafers to be reworked are clamped or picked up several times in tools, with possible contamination, for example by chips, leading to damage to the optically flawless surfaces. In order to prevent this, any mechanical post-processing is excluded according to the invention. The geometry and / or surface of the disk is produced in one piece during the manufacturing process (injection molding, injection compression molding). In this case, the edge area is preferably designed to be convex, the surface being formed with a special structure on the convex geometry. This structure fulfills the same task that is previously generated by the separate mechanical post-processing process (milling) in the form of a roughening. This special structure can completely or only partially cover the edge area of the pane, the edge area being delimited by the essentially plane-parallel side surfaces of the pane. It is thus possible for the edge region to be delimited by edges in the transition to the essentially plane-parallel side surfaces of the pane. This transition area between the edge area and the essentially plane-parallel surfaces of the pane can of course be carried out continuously or in jumps / steps. Depending on the shape or curvature of the disk, adapted to the injection molding tool, a tool separation of tool halves can coincide with such an edge of the previously described edge area. In this case, however, it is also possible that with a symmetrical convex configuration of the edge region, such a separation extends at the maximum of the convex curvature along the circumference of the disk. In the case of asymmetrically convex edge areas in which the maximum convex curvature is not located symmetrically between the two essentially plane-parallel surfaces, but is shifted relative to a plane-parallel surface, the separation between the tools will proceed according to this maximum convex positioning. The design of the edge area at the maximum of the convex curvature is advantageous with regard to the opening process or for separating the mold halves and thus demolding the disk, since it can be easily and simply demolded from the mold even if slides are used. In special cases, however, it is also conceivable for the edge region between the plane-parallel surfaces to run approximately orthogonally, that is to say at 90 ° to these plane-parallel surfaces. Demoulding is made much more difficult here, so that slides or special ejectors have to be provided in the tool and can thus make the manufacturing process significantly more expensive. Of course, it is possible that such an orthogonal and thus flat surface can also be designed as an edge area at inclined angles.

In all of these geometric designs of the edge area, a structure is provided, at least in part, on the edge area. This structure prevents the light introduced into the pane from causing light reflections within the pane and from escaping in the edge area and thus causing undesirable effects an illuminated edge of the disk of the display unit of the head-up display leads. This structure can cover the entire edge area or only partially, the structure being designed to be rounded or convexly concave from the edge area to the outside of the pane. Furthermore, the structure is not arranged uniformly on the edge region, but rather is designed to be irregular, with the convex or rounded sections also being able to have different sizes and dimensions. Overall, it has proven to be advantageous that, depending on the head-up display to be used, the pane of the display unit has a roughness of the structure between 3 μm and 25 μm. Depending on the resolution of the data information or image information to be displayed and the intensity of the light introduced into the pane, the roughness of the structure must be adapted accordingly. Furthermore, the aforementioned roughness of the structure is of great importance for demolding the pane from the injection molding tool after the injection molding process has been completed. The roughness of the structure and the corresponding convex design of the edge area must be coordinated with one another in such a way that no undercuts can arise between the individual structural elements and thus the pane can be easily removed from the mold. To use the pane in a display unit of a head-up display, it is subjected to a coating process several times after the injection molding process. Here, for example, a scratch protection lacquer, a primer and / or a partial mirror coating is applied as a coating to the entire pane, thus also to the edge area, in a dipping process, whereby the individual layers can be cured thermally or by UV radiation after the coating. Many common dip lacquers are suitable for this coating, for example also dip lacquers based on silicate, the interaction of the coatings and the structure of the edge area of the pane adequately preventing the desired effect of emerging light in the edge area. Of course, this also prevents light from shining into the pane of the display unit from outside via the edge area, so that no undesirable optical effects can arise when the data information or image information is displayed. This manufacturing method for producing a pane of a display unit of a head-up display with a structured edge area takes place in a single work step without the need for further post-treatments. All alternative methods require additional work steps, with mechanical edge processing, lasers, structural embossing in the form of rollers or cylinders, etching or particle beams. The roughness that can thus be achieved through additional work steps is thus achieved in one work step, the injection molding tool containing the shape of the edge area and the structuring of the edge area. The structures of the edge area are introduced into the injection molding tool by erosion, for example.

Further important features and advantages of the invention emerge from the subclaims, from the drawings and from the associated description of the figures on the basis of the drawings.

It goes without saying that the features mentioned above and those yet to be explained below can be used not only in the respectively specified combination, but also in other combinations or on their own, without departing from the scope of the present invention.

Preferred exemplary embodiments of the invention are shown in the drawings and are explained in more detail in the following description, with the same reference symbols referring to the same or similar or functionally identical components.

• 1 eine Prinzipdarstellung einer Anzeigeeinheit mit Scheibe eines Head-Up-Displays,
• 2 einen Scheibenabschnitt einer Anzeigeeinheit,
• 3 eine Vergrößerung eines Abschnitts des Randbereichs,
• 4 einen Schnitt durch ein Spritzgusswerkzeug mit Scheibe,
• 5a - 5c Konturdarstellungen möglicher Ausführungen des Randbereichs

They show, each schematically,

• 1 a schematic diagram of a display unit with a pane of a head-up display,
• 2 a disk portion of a display unit,
• 3 an enlargement of a section of the edge area,
• 4th a section through an injection molding tool with disc,
• 5a - 5c Contour representations of possible designs of the edge area

1 shows a schematic diagram of a display unit 4th with washer 5 a head-up display. Here is in a carrier unit 2 an ad 7th a light source 6th upstream, with light rays 8th , emitted from the light source 6th , through the ad 7th be sent. The ad 7th that also act as a display 7th is for the rays of light 8th the light source 6th translucent, being in the ad 7th those for the observer 1 provided data information or image information are generated. Through the rays of light 8th the light source 6th this information will be the display 7th on the disc 5 projected, with the disc 5 in the present version also with the carrier unit 2 connected is. The disc 5 the display unit 4th is a windshield / windshield 3 upstream so that the on the disc 5 incident light rays 8th as rays of light 9 towards the observer 1 be reflected. Thus arises for the observer 1 either on the disc 5 a partially transparent representation of the data information or image information. The disc 5 thus acts as a semi-transparent screen on which the information of the display 7th for the viewer 1 be reproduced recognizably. Of course, it is also possible to choose the optical arrangement or the information of the display 7th like that on the disc 5 to project that for the viewer 1 one of the windshield 3 upstream virtual image 10 arises. This virtual picture 10 arises in the direction of the observer's line of sight 1 aligned, the direction of view being that of the light beam 9 is equivalent to. Of course, the arrangement can correspondingly in 1 shown, can be combined by additional optical elements such as lenses, mirrors. This makes it possible to use the display unit 4th A head-up display can also be arranged in the smallest of spaces, for example inside a helmet or in the direct catchment area of glasses.

A section of the disc 5 a display unit 4th is in 2 pictured. This is the corner area of the pane 5 shown, with a convex rounded edge area 15th the disc 5 limited. The disc 5 is essentially made up of two plane-parallel disc surfaces 12th limited, these plane-parallel disk surfaces 12th (here only a disc surface 13th shown) in the transition area with the edge area 15th an edge 17th forms. The edge area 15th is essentially due to the transition area between the edge 16 and the plane-parallel disk surfaces 12th educated. In the representation of the 2 becomes the border area 15th through the edge 17th limited and there is no smooth transition of the edge 16 into the disc surface 13th occurs, is the edge 16 with the border area 15th identical. Of course, the edge can 16 also steplessly into the side window 13th or take place in several stages, this transition then being called the edge area 15th is defined.

This border area 15th is circumferential according to its contour with the structure 18th Mistake. The structure 18th consists here of rounded or spherical convex elevations, which are on the edge area 15th from the disc 5 are aligned facing outwards. The structure 18th is irregular in size, shape and design. The roughness of the structure 18th corresponds here to a range between 3 µm to 25 µm, whereby the exact selection of the roughness of the structure used 18th and the dimensions of the edge area 15th , the disc 5 as well as the one in the disc 5 projected image information / data information.

An enlargement of a section of the edge area 15th , as in 2 is described in 3 shown. Here, the disc 5 in their edge area 15th a convex configuration, this convex configuration having a structure 18th is provided. The structure 18th is essentially orthogonal to the edge area 15th pointing and is oriented in the direction of the plane-parallel disk surfaces 12th from the edges 20th , 21 of the disc surfaces 13th , 14th limited. With a sudden transition of the edge area 15th into a disk surface 13th , 14th are the limiting edges 20th , 21 identical to the edge 17th the 2 coincident. Approximately in the middle of the convex design of the edge area 15th is a dividing line 22nd shown. This dividing line 22nd corresponds to the parting line between two tool halves, which, as in the present case, thanks to the edge area 15th around the disc 5 extends. In a further embodiment it is possible that this dividing line 22nd with one of the edges 20th or 21 coincides, also being a combination of the dividing line 22nd with one of the edges 20th , 21 is possible and the other edge as a stepless transition of the edge area 15th into a disk surface 13th , 14th he follows. In these cases mentioned, the edge area is roughly halfway in the middle 15th the separation 22nd of the tool halves. For tool halves that have an asymmetrical edge area 15th may have the dividing line 22nd for example with one of the edges 20th , 21 coincide or in extreme cases the dividing line 22nd be present several times, usually running in parallel. This is the case, for example, when the edge area 15th is executed in multiple stages.

In the 4th is a section through an injection molding tool 25th with washer 5 pictured. The injection molding tool 25th exists in execution accordingly 4th from four individual tool halves 26th , 27 , 28 , 29 , with an upper tool half 26th and a lower tool half 27 in the area of the plane-parallel disk surfaces 12th are arranged. The edge area 15th two tool halves are assigned 28 , 29 , an upper mold half 28 and a lower tool half 29 provided, which is in the approximately central position of the edge area 15th the disc 5 along the dividing line 22nd a parting plane 30th own each other. Analogous to the descriptions of the previous ones 2 until 3 indicates the edge area 15th in the transition area to the plane-parallel disc surfaces 12th edge 20th , 21 that with the present tool version with the parting lines 31 and 32 coincide. After the injection molding process has been completed, this enables the pane to be removed from the mold easily and essentially free of damage 5 from the injection mold 25th , with the upper half of the tool 26th and the lower half of the tool 27 approximately orthogonal to the plane-parallel disk surfaces 12th be moved away. The edge area 15th associated upper and lower mold halves 28 , 29 can according to the geometric configuration of the convex shape of the edge area 15th be moved sideways. Is the geometric design of the convex shape of the edge area 15th chosen so that the structure 18th of the border area 15th Could have undercuts, it is possible after removing the upper and lower tool halves 26th , 27 the upper and lower mold halves 28 , 29 of the border area 15th obliquely from the planar alignment of the disc 5 to proceed. These targeted opening movements make it possible to remove possible undercuts from the tool halves without causing damage 28 , 29 can be demolded. Of course, it is possible that further tool halves and parting planes according to the design of the edge area 15th or the curvature and shape of the disc 5 customized to use. Slides or ejectors can also be used as required.

the 5a until 5c show contour representations of possible designs and shapes of the edge area 15th , where in 5a the edge area 15th is designed predominantly flat as an edge slope. The border area is in the transition area 15th executed rounded here, with a parting plane in the acute-angled area of the edge slope in the rounded transition 30th is provided. It is here in the further course of the disc 5 as a dividing line 22nd pictured. The in 5b to the plane-parallel disk surfaces 12th an asymmetrically convex edge area 15th shown. Along the largest rounding of the convex execution of the edge area 15th the dividing line runs here 22nd and thus forms a parting plane 30th the end. Here, too, are the transition areas between the edge area 15th and the plane-parallel disk surfaces 12th rounded. In the 5c is the edge area 15th the disc 5 corresponding 5a obliquely, but with one against the disc 5 directed curvature. This curvature can correspond to a segment of a circle or some other arc shape, the transition area to the plane-parallel disk surfaces 12th can be sharp-edged. These sharp-edged transitions also form the dividing lines at the same time 22nd as well as possible parting lines 30th the end.

List of reference symbols

1

Observer, eye

2

Carrier unit, dashboard

3

Windshield, windshield

4th

Display unit

5

disc

6th

Light source

7th

Display, display

8th

Beam of light

9

Beam of light

10

virtual image

12th

plane-parallel disk surfaces, plane-parallel surfaces

13th

Disc surface

14th

Disc surface

15th

Edge area

16

edge

17th

Edge

18th

Structure, roughness

20th

Edge

21

Edge

22nd

Dividing line, dividing edge

25th

Injection mold

26th

upper mold half washer

27

lower mold half washer

28

upper mold half edge area

29

lower mold half edge area

30th

Parting plane

31

Parting plane

32

Parting plane

Claims (18)

A pane (5) for a display unit (4) of a head-up display, - the light beams (8) for generating image information to be displayed are projected onto the pane (5), - the pane (5) in the field of view of an observer ( 1) is arranged - and the pane (5) has a partially reflective coating, - that the pane (5) of the display unit (4) has a delimiting edge (16) and the edge (16) is part of an edge region (15) of the pane (5), characterized in that - that the edge area (15) of the disk (5) is at least partially provided with a structure (18), - that the edge area (15) of the disk (5) has essentially plane-parallel disk surfaces (13 , 14) of the disk (5) is limited, - that the edge region (15) between the essentially plane-parallel disk surfaces (13, 14) of the disk (5) is asymmetrically convex. Disc (5) for a display unit (4) after Claim 1 , characterized in that the boundaries of the edge region (15) to the essentially plane-parallel disk surfaces (13, 14) of the disk (5) are formed by an upper edge (20) and a lower edge (21). Disc (5) for a display unit (4) after Claim 1 , characterized in that the delimitation of the edge region (15) to the essentially plane-parallel disk surfaces (13, 14) of the disk (5) takes place in a continuous transition or in at least one step. Disc (5) for a display unit (4) after Claim 1 , characterized in that the structure (18) of the edge region (15) is designed irregularly. Disc (5) for a display unit (4) after Claim 4 , characterized in that the structure (18) of the edge region (15) is convex and / or rounded. Disc (5) for a display unit (4) after Claim 5 , characterized in that the structure (18) of the edge region (15) corresponds to a roughness between 3 and 25 µm. Disc (5) for a display unit (4) after Claim 6 , characterized in that the structure (18) of the edge region (15) is provided with at least one coating, wherein the coating can be a scratch protection lacquer, a primer or an at least partial mirror coating. Disc (5) for a display unit (4) according to one of the preceding claims, characterized in that the disc (5) and the edge region (15) are made in one piece from a thermoplastic material. Method for producing a disc (5) according to Claim 1 , characterized in - that the disc (5) is produced in one piece with the edge region (15) by means of an injection molding process. Method for producing a disc (5) according to Claim 9 , characterized in that the boundaries of the edge region (15) to the essentially plane-parallel disk surfaces (13, 14) of the disk (5) are formed by an upper edge (20) and a lower edge (21). Method for producing a disc (5) according to Claim 9 , characterized in that the delimitation of the edge region (15) to the essentially plane-parallel disk surfaces (13, 14) of the disk (5) takes place in a continuous transition or in at least one step. Method for producing a disc (5) according to Claim 9 , characterized in that the structure (18) of the edge region (15) is designed irregularly. Method for producing a disc (5) according to Claim 12 , characterized in that the structure (18) of the edge region (15) is convex and / or rounded. Method for producing a disc (5) according to Claim 13 , characterized in that the structure (18) of the edge region (15) corresponds to a roughness between 3 µm and 25 µm. Method for producing a disc (5) according to Claim 14 , characterized in that the structure (18) of the edge region (15) is provided with at least one coating, wherein the coating can be a scratch protection lacquer, a primer or an at least partial mirror coating. Method for producing a disc (5) according to one of the Claims 9 - 15th , characterized in that the disc (5) and the edge region (15) are made in one piece from a thermoplastic material. Method for producing a disc (5) according to one of the Claims 9 - 16 , characterized in that at least one dividing line (22) of the injection molding tool (25) runs in the symmetrical or asymmetrical convex edge region (15). Method for producing a disc (5) according to one of the Claims 9 - 17th , characterized in that at least one dividing line (22) of the injection molding tool (25) with the upper edge (20) or the lower edge (21) of the essentially plane-parallel disk surfaces (13, 14) of the disk (5) of the edge region (15) runs.

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