The invention is in the field of displaying information on a glazing element of a vehicle or a cover unit. More specifically, the invention is in the automotive field, but it is not restricted to this field but can be implemented in buses, railway cars, boats, airplanes or other vehicles. More specifically, the invention is related to a vehicle compound glazing unit and a vehicle glazing and display system, comprising a vehicle compound glazing unit and a projector for projecting an image to the glazing unit.

US 7 157 133 discloses the basic concept of diffuse reflection with embedded diffusing surface.

EP 2 185 966 discloses an element with a diffusing surface on which a reflective layer is deposited, the whole being in an envelope of the same refractive index as the diffusing element. The assembly is designated as a numerical aperture expander working in reflection, which seems functionally close to a diffuser and a transparent element in transmission. In this patent, the integration of such an element in a head-up display (HUD) projection system for generating virtual images is mentioned.

US 8 519 362 B2 describes an HUD system assembled into a car. It is based on a laminated windshield where the HUD function is generated by a layer of luminophore material. US 7 230 767 B2 describes a display system in a car glass pane using a light emitting material projecting the image to the driver. The image is a virtual image, focused meters away from the eyes of the driver and from the windshield.

A preparation process of an HUD system integrated into a laminated glass pane is described in EP 2 883 693. The laminated glass pane comprises an interlayer having a wedge shape for avoiding ghost images. The interlayer is made from a thermoplastic foil.

US 2012/0224062 A1 discloses a head up display comprising a laser based virtual image providing system and a system for sensing a lateral road position.

Regarding the general concept of transparent glazing units which have a certain degree of diffuse reflection, there are several patent publications, e.g. EP 2 670 594, EP 2 856 256, EP 2 856 533, EP 2 872 328, EP 3 063 002, WO 2012 104 547, WO 2018 015 702, and FR 3 054 17. In these patent documents, it is, inter alia, disclosed that such diffusely reflective glazing can contain a rough internal surface and a coating provided thereon and that such glazing can be used for OLED display solutions or for projection-based display solutions.

EP 3 395 908 A1 discloses a transmission type screen as head-up-display for automotive applications, in which the screen is particle based.

In EP 3 151 062 A1 a video projection structure for integration into an automotive window is presented, wherein the window contains a reflection film applied on a surface having random irregularities.

JP 2016 9271 A discloses a video display system, which is equipped with detection means to detect a movement of the observer, wherein display system can be operated by the movement of the observer.

DE 10 2004 051 607 A1 discloses a device and a method for displaying a digital image onto a geometrical and photometrical non-trivial surface. In particular, the document discloses to project an image with one or more projectors onto a non-planar surface. The projection method comprises in particular a calibration with a camera connected to a control system which is adapted to control the one or more projectors for adjusting the projection of the image for each displayed pixel of the image.

EP 3269547 A1 discloses a vehicle glazing comprising a first and a second pane connected by an intermediate layer, wherein the glazing includes a first region with a wedge-shaped cross section, a second region with a wedge-shaped cross section and a transition region connecting the first and second regions. The transition region also shows a wedge-shaped cross section. At least one of the first and second regions includes a region used for a head up display.

It is an object of the present invention, to provide a vehicle glazing and display system and corresponding vehicle compound glazing unit, which are adapted for a broad range of applications in future mobility solutions. More specifically, it is an object to provide a glazing unit having different projection areas for a vehicle, in particular as windshield, and a system which makes it possible to display rich content to basically all persons which use a vehicle or at least to all those persons, which sit close to a respective glazing unit. Furthermore, a solution is required which can be implemented, to a far extent, on the basis of available technologies and which is safe, reliable and cost-efficient. These, and further, objects are solved by a vehicle compound glazing unit according to claim 1 and a vehicle glazing and display system according to claim 12. Preferred embodiments of the invention are subject of the respective dependent claims.

The vehicle compound glazing unit according to the invention has a first region, a second region and a third region. The vehicle compound glazing unit comprises:

A first pane having a first face and a second face, a second pane having a third face and a fourth face, and a first interlayer formed by a thermoplastic polymer, in particular of PVB. The first interlayer is arranged between the second face of the first pane and the third face of the second pane.

The first face and the second face are opposing surfaces of the first pane. The third and the fourth face are opposing surfaces of the second pane.

The vehicle compound glazing unit further comprises a diffusely reflecting structure in the second region, which diffusely reflects incident light directed to the glazing unit from the interior of the vehicle and having a maximum gain in the range of 0.1 to 0.8, preferably between 0.3 and 0.6 and an intrinsic viewing angle a for a real image element generated within the glazing surface of more than 60°, in a first direction and of more than 30°, in a second direction, perpendicular to the first direction.

The first region comprises the third region at least partly. First and second region are non-overlapping regions of the glazing unit. As a consequence of these two restrictions, the third region and the second region also do not overlap. The third region is supposed to be suitable for a HUD-projection with a virtual image. This third region is therefore suitable for projection systems based on specular reflection. The second region is suitable for projecting a real image with a projector, wherein the system is based on diffuse reflection. The first face and the fourth face are preferentially smooth surfaces.

The first region is located in the middle of the glazing unit, while the second region is located at an outer region of the vehicle compound glazing unit. This means that the distance between the circumferential edge of the vehicle compound glazing unit and the second region is smaller than the distance between the circumferential edge of the vehicle compound glazing unit and the first region. The third region is at least party located within the first region. The third region and the second region do not overlap. The second region is suitable for a projection with a real image, while the third region is suitable for a HUD-projection with a virtual image. As the second and the third region do not overlap, the projections are not disturbed by each other. The HUD-projection in the third region is a virtual image, which has a plane of projection outside the plane of the glazing. For an observer, the virtual image is located behind the glazing, which means on the opposite surface of the glazing than the observer. Thus, for the driver of a car the virtual HUD-image appears to be on the street. The virtual HUD-image, which is based on specular reflection, is visible over a small angle width. The HUD-projection is preferably used for projecting information relevant for the driver, e.g. navigation information. The real image projection within the second region is based on diffuse reflection and visible within the plane of the glazing over a wide angle width. Thus, the real image projection is suitable to view information, which is relevant to all occupants of a car, e.g. media or entertainment data.

The maximum gain, also denoted as peak gain, is the highest gain value, which is reachable for the screen. The gain and is retrieved by calculating the ratio between the screen luminance and the ideal screen luminance of an ideal Lambertian diffuser. Thus, the gain value of the screen is standardized by the ideal screen, for which the gain is defined as 1.0. The screen luminance of the screen is measured and compared to the screen luminance of the ideal screen under the same conditions. For the non-ideal screen, a lower luminance will be achieved than for the ideal screen. The luminance of the screen is set in relation to the luminance of the ideal screen, which yields the gain value of the screen as value between 0 and 1 . For calculation of the maximum gain, the highest luminance, which is measured for the screen is set in relation to the luminance of the ideal screen.

The intrinsic viewing angle a depicts the angular width for which the gain is larger than half of the maximum gain. This is described in detail in Figure 5.

In order to display information on the vehicle glazing unit, e.g. a windshield, to driver and passengers, a combination of Head-Up Display (HUD) technology and transparent screen (TS) technology is used. This combination has the advantage to overcome the limitations of each of the two technologies, and allows to display both:

- a virtual image to the driver, who is interested into having the image at a distance from the eyes, in order to keep his eyes focused on the road; - a real image to all the other passengers, who are interested into having infotainment or augmented reality information displayed in the pane of the glass on the glazing, e.g. windshield. This allows for example to watch videos or read augmented reality information displayed and focused on the glazing, like on a transparent display.

Both displays, HUD and transparent screen, are based on different technologies. HUD works with specular reflection, while TS works with diffuse reflection.

By the diffusively reflecting structure in the second region of the glazing unit the second region gets suitable for projection with a real image.

The third region of the glazing unit is suitable for a HUD-projection with a virtual image, which can be achieved by a wedge shaped interlayer and/or with a coating suitable to reflect p-polarized light.

In a first preferred embodiment of the glazing unit the interlayer has a wedge shape with a wedge angle cp. The wedge is preferentially uniform for the glazing unit. The wedge shaped interlayer avoids the formation of ghost images of the HUD-projection. Wedge shaped interlayers are commercially available.

In a second preferred embodiment of the invention, the vehicle compound glazing unit comprises a reflective film, which is suitable to reflect p-polarized light. The film suitable to reflect p-polarized light is present at least within the third region of the glazing. In order to reach the best possible image quality both for the HUD image and for the TS image, different technical solutions are used. In order to suppress the ghost image in the HUD zone, the p-polarized reflecting film could be used in combination with a p- polarized light emitting projector, projecting at an angle to the glazing normal, which is close to the Brewster’s angle (-56° for the interface air to glass). In order to diffuse the light in the direction of the eyes of the passenger, the transparent screen film should be laminated parallel to the inner glass surface. Preferably, the vehicle compound glazing unit stack comprises (inner to outer order):

1 - Inner glass

2 - thermoplastic interlayer without wedge shape, e.g. flat PVB

3 - Functional layer comprising either light-diffusing transparent screen film or p- polarized light reflecting film (depending on the region) 4 - thermoplastic interlayer without wedge shape, e.g. flat PVB

5 - Outer glass

As mention in position 3 of this layer stack, a functional layer comprising a light-diffusing transparent screen film or a p-polarized light reflecting film implemented between two sheets of thermoplastic interlayer. Which of the films is used depends on the region of the glazing. Within the third region the p-polarized light reflecting film is used, while in the second region the functional layer is a light-diffusing transparent screen film. This surface division is favorable in order to display the HUD image to the driver and the TS image to driver and all passengers. If the glazing is used as windshield The HUD active part of the windshield will be in front of the driver, while the TS active part will be outside the central region of the windshield. The transparent screen display is preferably outside the type A viewing region of the windshield in accordance with ECE R43, more preferably outside the type A and B viewing regions of the windshield in accordance with ECE R43. Alternatively, to the light-diffusing transparent screen film, a reflective coating can be applied on a textured glass surface.

By implementation of such a vehicle compound glazing unit different light polarizations can be used for the two images. For example, the head up display projection is accomplished by use of p-polarized light, while the transparent screen image is projected by use of non polarized or s-polarized light.

In a third preferred embodiment the glazing unit comprises a film reflecting p-polarized light in combination with a wedge shaped interlayer. The film reflecting p-polarized light could be for example be integrated within the wedge shaped interlayer.

The intrinsic viewing angle a for a real image element generated within the plane of glazing in the second region is larger than 40°, preferably larger than 60° and more preferably larger than 70° or more in a first direction and larger than 20°, preferably larger than 30° in a second direction, which is perpendicular to the first direction. When using these intrinsic viewing angles within practical application at standard environment conditions, a practical viewing angle of larger than 60°, preferably larger than 90° and more preferably larger than 120° or more in a first direction and larger than 30°, preferably larger than 45° in a second direction, which is perpendicular to the first direction, can be achieved. The practical viewing angle is dependent of both the luminous environment and the used projector. Nevertheless, the practical viewing angle is a commonly used feature for screen specification and can be determined for chosen environment conditions related to a particular use case. For standard environmental conditions and projector specification the following values could be used:

External illuminance 2200 Lux (outside the car); internal illuminance 100 Lux (inside the car); flux from projector 3500 Lumen; Projection surface: 16:9 screen with 9“ diagonal (20 cm width); the practical view angle can then be extracted from gain curve via a mathematical formula.

The practical viewing angle is studied on the basis of the contrast of the screen. The contrast of a screen is commonly defined as the luminance ratio between a white and a black picture, wherein a minimum ratio of 4.5: 1 (white picture to black picture) is considered as necessary for information reading. Based on this, the practical viewing angle can be derived as the observation angle Q within the position where at least the minimum contrast of 4.5: 1 is achieved.

The intrinsic viewing angle a of a projection screen is measured at the full width half maximum (FWHM) of the peak around the maximum value of the gain, independent of the value of the observation angle Q at the peak center. The Q =0° reference for the gain curve measurement corresponds to the specular reflection direction. Thus, the intrinsic viewing angle a is a property of the screen and not dependent on environmental luminance and projector specification. Thus, as the maximum of the gain curve often occurs at 9=0°, the intrinsic viewing angle can also be defined in this case as twice the observation angle Q at the position of the gain curve where the half maximum width of the gain curve is achieved.

The viewing angle (intrinsic and practical) shall be maximized as large viewing angles are necessary to ensure that all passengers of a vehicle can clearly see the projected content at the same time independent of the seat occupied by a person. However, with a given screen total reflectivity, a compromise between a high peak gain and a large viewing angle has to be found. The vehicle glazing according to the invention provides such a good compromise between peak gain and viewing angle.

In a preferred embodiment of the invention, the transparent screen of the vehicle glazing has a maximum gain between 0.1 and 0.8 and a practical viewing angle superior to 60° in one direction and larger than 30° in the other one. Typically, for the practical viewing angle values between 120° to 150° in horizontal plane and between 30 and 180° in vertical plane are derived. Within the intrinsic angle definition an intrinsic viewing angle superior to 40°, more preferably superior to 60°, even more preferably between 70° and 150°, in horizontal plane and between 20° and 180°, preferably between 30° and 180°, in vertical plane is derived. Vertical plane and horizontal plane are defined within the assembly situation of the vehicle glazing within the car body.

In a preferred embodiment of the invention, the transparent screen of the vehicle glazing has a maximum gain between 0.1 and 0.8 and a practical viewing angle superior to 60° in one direction and larger than 30° in the other one. Typically, for the practical viewing angle values between 120° to 150° in horizontal plane and between 30 and 180° in vertical plane are derived. Within the intrinsic angle definition an intrinsic viewing angle superior to 40°, more preferably superior to 60°, even more preferably between 70° and 150°, in horizontal plane and between 20° and 180°, preferably between 30° and 180°, in vertical plane is derived. Vertical plane and horizontal plane are defined within the assembly situation of the vehicle glazing within the car body.

Thanks to the mentioned practical and intrinsic viewing angles, all the occupants in the vehicle can see the display when the projector is on. According to a further aspect of the invention, the displayed image is a real image. A real image differs from a virtual image concerning the plane of focus. For virtual images, the plane of focus has a certain distance to the projection screen, e.g. one meter or up to several meters. In contrast to this for real images the plane of focus is near to the screen. Preferably, the plane of focus for a real image according to the invention has a maximum distance of 30 cm to the projection screen.

When the projector is off, the glazing is optically similar to a traditional glazing, maintaining transparency with a slightly higher haze value. A typical haze value for such a glazing is between 1 % and 6 %, preferably between 1.5 % and 4.5 % measured according to the standard ASTM D 1003. The haze measures the fraction of transmitted light that is deviated from the straight path with an angle larger than 2.5°. High haze values correspond to a loss of contrast of the image projected on the screen. Within the given range of low haze values, a good transparency of the screen is obtained. Preferably, the haze value within the vision zone A according to ECE R43, more preferably the haze value within the vision zones A and B according to ECE R43, does not exceed 2 %. To achieve this value, the second region with a diffusively reflecting transparent screen film is preferably not within the vision zone A, more preferably not within the vision zones A and B according to ECE R43. According to a further preferred aspect, the reflective layer or surface within the glazing unit has a transmission of visible light of higher than 60 %, preferably of 70 % or more, for example 80 % or more. These transmission values (also referred to as global luminous transmission TL) quantify the ability of the reflective layer or surface to transmit light of wavelength between 400 nm to 800 nm, which is the range of the spectrum visible to human eye. For those measurements, no distinction between diffused light and non- diffused light has to be made. Nevertheless, the technology according to the invention is also applicable to glazing in which a lower light transmission is desired. The screen ensemble of the invention may be used in glass roofs for vehicles, which usually comprise tinted glass or plastic components and have an overall transmission of visible light below 30 %. Such an application is of particular interest in combination with autonomous driving technology. In this case, the roof could for example be used as entertainment screen. For windshield application a high transmission is desirable.

To measure the gain and determine suitable viewing angles of a transparent screen, one has to measure the luminance of the screen as a function of the observation angle with a projector illuminating the screen with a normal incidence (0°). The luminance of an ideal screen (Lambertian reference called Spectralon) is measured under the same conditions. An ideal screen is defined as a screen whose luminance does not depend on the projection or observation angle and whose reflectivity is 100%. The Lambertian reference screen is a surface perfectly obeying Lambert’s cosine law saying that the luminous intensity observed from an ideal diffusely reflecting surface is directly proportional to the cosine of the angle between the direction of the incident light and the surface normal. The human eye can only recognize the luminance, which is a measure of luminous intensity per unit area of light travelling in a given direction, and describes the amount of light that is reflected from a particular area. Thus, a Lambertian surface with ideal diffuse reflection is seen by the human eye as showing the same luminance and brightness independent of the observation angle from which it is viewed. Experimentally an ideal Lambertian diffuser is accessible by commercially available reference materials known as “Spectralon”, which is made of sintered polytetrafluoroethylene (PTFE). To retrieve the gain of the screen at each observation angle, the ratio between the screen luminance and the ideal screen luminance is calculated. The peak gain of the screen is the maximum gain value reachable for the screen. The maximum gain (also referred to as peak gain) is often measured at 0° but some specifically designed screen may have their maximum gain at another observation angle. It is to be noted that for a transparent screen, the value at 0° may not be measureable because of the hotspot (specular reflection of projector light on the external flat glazing surface) and is therefore extrapolated from gain at small angle.

Preferred intrinsic viewing angles are defined from the gain as being within the full width half maximum of the gain curve (see Figure 5). This definition is an intrinsic one. The gain denotes the luminance of the projection screen relative to the luminance of an ideal screen, which is a perfect Lambertian diffuser.

An alternative, more practical, definition of the viewing angle would be to define a practical viewing angle as the observation angle where the contrast is lower than 4.5: 1 , but such definition depends on observation and illumination conditions and projector. Thus, the intrinsic definition of viewing angles, being within the full width half maximum of the gain curve, is preferred. The gain curve can be determined as already described and has for example the shape of a Gaussian curve.

The inventors detected that not only observation angles inferior to the half of the intrinsic view angle (i.e. within the full width half maximum of the gain curve) are suitable for practical application of the transparent screens. Adequate observation results can be achieved under observation angles inferior to the half of a practical view angle in the range of 120° to 180° within horizontal plane, preferably 120° to 150° within horizontal plane, and 30° to 180° within vertical plane.

To achieve a sufficient contrast in combination with the clear glass stack and with the aforementioned display dimension, the projector should have an output flux higher than 1000 Lumen, better higher than 3000, ideally between 2000 and 10Ό00. The best projector flux values have to be chosen depending on the environmental conditions.

The first region is located in the middle of the glazing unit and the second region is located at an outer region of the vehicle compound glazing unit, preferably surrounding partially or completely the first region. In particular the second region is located along to opposing edges of the vehicle compound glazing unit, and the third region is located in the first region. The second region might have some cut-out for the third region and thus the first region extending to an outer edge.

In particular, the first region comprises a type A viewing region of a windshield in accordance with ECE R43, wherein the second region is exclusively located outside the type A viewing region (also depicted as vision zone A), for example within in a type B viewing region (also depicted as vision zone B) of a windshield in accordance with ECE R43, or more preferably outside vision zones A and B.

In an embodiment, the first pane is supposed to be arranged as outer pane and the second pane is supposed to be arranged as inner pane, wherein each of the first pane and second pane is made from glass or plastic.

In a further embodiment, the diffusely reflecting structure is a rough surface area of the third face or a coating of the third face.

In an embodiment, the vehicle compound glazing unit comprises a second interlayer and a third interlayer. The second interlayer comprises the diffusely reflecting structure and a transparent region, and the third interlayer is made from a thermoplastic polymer, preferentially from the same material as the first interlayer or from a material having the same or nearly the same refraction index, and has in particular a uniform thickness. The second interlayer is sandwiched between the first interlayer and the third interlayer.

The second interlayer may comprise a PE, PET, TAC, PVB, PMMA, PU, TPU or polycarbonate sheet. Such sheets are basically commercially available or can be manufactured upon request of the manufacturer of the vehicle compound glazing unit, tailored to the specific optical requirements according to the invention.

In an alternative embodiment, a partially rough glass sheet can be used instead of the partially rough plastic film. This has the advantage that a glass sheet can be integrated in standard lamination processes.

The diffusely reflecting structure may comprise nanoparticles or microparticles, or a random nanostructure or a random microstructure. More specifically, the nanoparticles or microparticles are silica or polymer or liquid crystal particles. Metal or metal oxide particles can also be used. More specifically, the nanoparticles or microparticles can have spherical shape and/or are transparent or translucent.

Plastic sheets with a diffusely reflective coating comprising titanium oxides TiO _x particles or silver particles as well as plastic sheets with an organic diffusely reflective coating comprising cholesteric liquid crystals have turned out to be especially suitable for the screen applications according to the invention. Most preferably the diffusely reflective plastic sheet contains liquid crystal particles, which are oriented within a matrix. In a further embodiment a heatable layer or coating arranged at the second face of the first pane or the third face of the second pane, the heatable layer or coating being provided with two or more electrical contacts, in particular bus bars. Alternatively, or additionally, a partial or complete coating, for example IR-reflective coating, may be provided at the second or third face, wherein a partial coating is preferably located in the second region.

The vehicle compound glazing unit may be one of a glass roof, a windshield, a side window or a back window.

According to a second aspect of the invention, a vehicle compound glazing system comprises a vehicle compound glazing unit as described above, a first projector for projecting an image in the third region of the vehicle compound glazing unit to generate a virtual image in the plane of the glazing unit, and at least one second projector for projecting an image in the second region of the vehicle compound glazing unit to generate a real image in the plane of the glazing unit.

The first projector may be suitable to be arranged in the dashboard or at the roof of the vehicle and/or one or more of the second projectors may be suitable to be arranged in the dashboard of the vehicle or at the roof of the vehicle. In an embodiment, a single projector can be used as first and/or second projector.

In an embodiment the vehicle compound glazing system comprises at least two second projectors and a projector control unit connected to the at least two second projectors and adapted to calibrate the projection of the image on a pixel base.

As the available distance between the projector and the glazing, in the orthogonal direction to the glass surface (projection distance), is usually between 2 cm and 60 cm, preferably between 7 cm and 40 cm, a preferential option is to use a short-throw projector. The throw ratio (size of the image/distance between projector and screen) is usually larger for short-throw projectors. In a short-throw projector, there is often a folding optics so that the projector image can be displayed in a plane that is perpendicular to the output lens. The projector may be a projector having a conventional lamp, a LED or a LASER as illumination means.

The system may comprise three, four, five, six, seven, eight or more projectors, in particular second projectors. The projectors are preferentially connected with a projector control unit which controls the projectors such that a combined image is displayed for the two or more projectors. In particular, the projector control unit comprises a camera for the calibration of the combined image such that a single image seems to be projected. The projector control unit is as well adapted to correct the projection of the image for a curvature of the glazing unit.

The above-referenced generation of hot spots in the glazing unit can, to a certain extent, be suppressed by a suitable arrangement of the respective (inner and outer) faces of the glazing unit and, in particular, of the diffuse reflective sheet coating or surface, respectively. In a preferred embodiment, the projectors are arranged such that a possible hot spot is located above a frame in which the projectors are arranged. By such an arrangement, a possible generated hotspot is not visible from a seating position inside the vehicle. As an additional means for suppressing the hot spots at least one local blind can be arranged close to the output lens of the projector, in a suitably pre-defined position.

Additionally, or alternatively, if the incident light at the glazing unit is polarized, in particular p-polarized, it can be suppressed when the incident angle is near to the Brewster angle.

The image projected on the transparent screen is due to diffuse reflection. The reflection of a glazing is defined as diffuse reflection when incident radiation on the glazing with a given angle of incidence is reflected in a plurality of directions. Specular reflection occurs when incident radiation on the glazing with a given angle of incidence is reflected with an angle of reflection equal to the angle of incidence. Likewise, transmission is defined as specular when incident radiation with a given angle of incidence is transmitted with an angle of transmission equal to the angle of incidence. However, to keep transparency on the whole glazing, the inner face and outer face of the glazing are flat and therefore induce specular reflection from the projector beam. To achieve the experience, the light reaching the eye of the vehicle passengers should be given by the “diffuse reflection” of the projected image on the glass. The specular reflection on the inner and outer face of the glazing should be avoided. The specular reflection is also referred to as “hot-spot”, which glares the observer when it is directed to the viewer. The direction of the hot-spot is available via the law of reflection saying that the angle of reflection equals the incidence angle. To avoid glaring the viewer by the hot-spot, the hot-spot and the observation direction of all passengers of the vehicle show preferably an angle distance of at least 5°, more preferably at least 10°, most preferably at least 20°.

In a preferred embodiment of the vehicle compound glazing system the first projector is a light source for p-polarized light and/or the at least one second projector is a light source for non-polarized light or s-polarized light. Preferably, the first projector for the HUD image, which is emitting p-polarized light, is positioned in the dashboard in front of the driver and uses a moving mirror in order to adapt the eye-box to the height of the driver. The second projector for the transparent screen image is placed in the symmetry plane of the car, in order to project on the complete transparent screen surface and in order to avoid packaging issues.

Embodiments and aspects of the invention are illustrated in the drawing. In the drawing shows

Fig. 1a, b a schematic of a vehicle glazing and display unit according to an embodiment of the invention,

Fig. 2a an embodiment of a vehicle glazing and display unit of the embodiment according to Fig. 1a in schematic cross section along

AA’,

Fig. 2b another embodiment of a vehicle glazing and display unit of the embodiment according to Fig. 1a in schematic cross section along BB’,

Fig. 3a, b schematic view of possible arrangements of the vehicle glazing and display system,

Fig. 4a, b some configuration examples for windshields with projector arrangements and

Fig. 5 an illustration for explaining definitions of the term “gain” in the context of the invention

Fig. 1 a shows an exemplary vehicle glazing and display unit 2. The vehicle glazing and display unit 2 might be a windshield of a car. The vehicle glazing and display unit 2 comprises a first region 4, a second region 6 and a third region 7. The first region 4 is located in the middle of the vehicle glazing and display unit 2 and the second region 6 is located in the lower and upper region along the top and bottom edge of the vehicle glazing and display unit 2. The third region 7 is located in an area within the first region that is supposed to be in front of a driver of the vehicle.

Fig. 1 b shows an alternative vehicle glazing and display unit 2. The vehicle glazing and display unit 2 might as well be a windshield of a car. The second region 6 is located in an outer region of the vehicle glazing and display unit 2 surrounding the first region 4. The third region 7 is located in an area within the first region 4 that is supposed to be in front of a driver of the vehicle.

Fig. 2a shows a cross-section of one embodiment of the above vehicle glazing and display unit 2 along A-A’ meaning from bottom to top through the windshield. The vehicle glazing and display unit 2 comprises a first pane 10 with a first face I and a second face II and a second pane 12 with a third face III and a fourth face IV. The first pane 10 and the second pane 12 are a glass or plastic pane. Between the second surface II of the first pane and the third face III of the second pane 12, there is a first interlayer 14 being a wedge shape foil from a thermoplastic polymer. The wedge angle f is located in the A-A’ plane. This first interlayer 14 is located at the second face II of the first pane 10, which is preferably an outer pane. Between the first interlayer 14 and the third face III of the second pane 12, a second interlayer 19 and a third interlayer 15 are arranged with a stacking order first interlayer, second interlayer, third interlayer. The third interlayer 15 is a thermoplastic layer, which can be made from the same material as the first interlayer 14. The second interlayer 19 comprises a transparent screen region 19a with a diffusely reflecting structure in the second region 6 and a transparent region in the first region 4, which is depicted as layer with parallel surfaces. The diffusely reflecting structure is depicted with a rough face. However, the reflecting structure might additionally or alternatively comprise nanoparticles or microparticles. The second interlayer 19 might comprise a PE, PET, TAC, PVB, PMMA, PU, TPU or polycarbonate sheet.

Fig. 2b shows a cross-section of another embodiment of the above vehicle glazing and display unit 2 along B-B’ meaning from bottom to top through the windshield. The vehicle glazing and display unit 2 comprises a first pane 10 with a first face I and a second face II and a second pane 12 with a third face III and a fourth face IV. The first pane 10 and the second pane 12 are a glass or plastic pane. Between the second surface II of the first pane and the third face III of the second pane 12, there is a first interlayer 14 being a flat thermoplastic polymer film without wedge shape. This first interlayer 14 is located at the second face II of the first pane 10, which is preferably an outer pane. Between the first interlayer 14 and the third face III of the second pane 12, a second interlayer 19 and a third interlayer 15 are arranged with a stacking order first interlayer, second interlayer, third interlayer. The third interlayer 15 is a flat thermoplastic layer, which can be made from the same material as the first interlayer 14. The second interlayer 19 is a functional film, which comprises a transparent screen film in a transparent screen region 19a and a head up display film in a HUD region 19b. The HUD region 19b is located within the third region 7, while the transparent screen region 19a is within the second region 6. The transparent screen region 19a comprises a transparent screen film with nanoparticles or microparticles. The head up display region 19b comprises a head up display film, which has a high reflection of p-polarized light. Suitable HUD films and transparent screen films are commercially available. Within other regions of the second interlayer 19, in which neither a HUD film nor a transparent screen film is present, thermoplastic layers can be present, e.g. of the same material than the first interlayer 14 and the third interlayer 15.

Fig. 3a and Fig. 3b shows a vehicle 100 with a vehicle glazing and display system 1. The vehicle glazing and display system 1 comprises a vehicle glazing and display unit 2, which is in the depicted case a windshield 3. The vehicle glazing and display system 1 further comprises a first projector 30a and a second projector 30b. The first projector 30a projects a virtual image in the third region 7, wherein the second projector 30b projects a real image into the second region 6. The first projector 30a is located in the dashboard and is projected for a first occupant 200 of the vehicle 100. The first occupant 200 is preferentially a driver. The second projector 30b might be located in the dashboard as depicted in Fig. 3a or at the roof as depicted in Fig. 3b. The image of the second projector 30b is visible as well for a first as for a second occupant 200, 201. Optionally, there might be several second projectors 30b, which might be as well located in the dashboard and/or at the roof of the vehicle. In case of several second projectors, a projector control unit is preferably connected to the at least two second projectors and which is adapted to calibrate the projection of the image on a pixel base. If the embodiment of Figure 2b, comprising a HUD film with high reflectance for p-polarized light, is used light of different polarization can be used for the two images. The head up display projector uses p-polarized light in this case, while the transparent screen image is based on non polarized or s-polarized light.

Fig. 4a and 4b show two possible arrangements of the second projector 30b relative to the windshield 3, as already explained further above. It can be recognized that in the arrangement of Fig. 3a, where the second projector 30b is arranged below the windshield and emits its light in a vertical direction, the hot spot direction can be within the angle of view of passengers inside the vehicle, whereas this is almost excluded in the arrangement of Fig. 3b, where the projector is arranged below the roof of the vehicle. For the arrangement of Fig. 3a it may, therefore, be required to provide specific means for “masking” the hot-spots, as also mentioned further above. If there are no geometric constrains in integration of the projector to the dashboard, this “masking” is not needed as the geometry of projector and screen will be chosen in a way that the hot-spot is not directed towards the viewer. A masking can be avoided if over the whole picture, the angle b is comprised between -110,6° and 0°. Corresponding position and image size depends on the projector throw ratio and/or geometry. The arrangement of Fig. 3a is preferred as the viewing angle and gain are within the specification according to figure 5 (gain/2 corresponds to a) and thus the contrast of the image is better. The embodiment of Fig. 3b is operating within a region of smaller gain (flat section of curve in figure 5), which means that a higher luminance is needed.

Fig. 5 shows the parameter “gain” with respect to a screen, e.g. the windshield 3 in Fig. 1 , referring to the explanations further above. The gain measurements were carried out using a luminance meter, and a videoprojector. The luminance is measured at various observation angles for a given incidence angle of the projected light. The projection angle was set as close as possible to 0° (normal to the screen). When the projection angle is held fixed, the gain depends only on the observation angle Q. The luminance meter position is consequently adjusted so that when the observation angle is set to 0° in the horizontal plane, the luminance meter is aligned with specular reflection; the observation angle is therefore really equal to 0° as the specular direction is taken as the reference for observation angle measurement. Luminance measurements were carried out every five degrees 5° to 75° (measured in the horizontal plane) in an unlit environment isolated from any light source other than the videoprojector. A Spectralon measured under the same conditions was used to standardize the luminance measurements and to extract the gain therefrom. The intrinsic viewing angle a can be derived from these measurements as the full width half maximum of the gain curve and depicts the angular width for which the gain is superior to half the peak gain. Reference signs

1 Vehicle glazing and display system

2 Vehicle compound glazing unit

3 Windshield

4 first region

6 second region

7 third region 10 first pane

12 second pane

14 first interlayer, thermoplastic interlayer

15 third interlayer, thermoplastic interlayer 19 second interlayer, functional interlayer 19a transparent screen region

19b head up display region 30a first projector 30b second projector 32 dashboad 34 roof 100 vehicle

200 first occupant

201 second occupant

I first face II second face

III third face

IV fourth face