Window glass detection

Abstract

A method of detecting a glazing is described. The glazing is configured for installation in a vehicle having a head-up display projector that employs a first projection distance from an eyebox location. The detection method includes positioning the window pane relative to the light source; directing light from the light source to illuminate a portion of the first head-up display area to produce a first virtual image at a first image plane, the first image plane being a first distance from the eyebox position; imaging the first virtual image at the first image plane using an imaging system to capture a first image; and determining a first performance parameter of the glazing using the first image; wherein the first distance is different from the first projection distance. An apparatus for performing the method is also described.

Description

[0001] The present invention relates to a method for detecting window glass having at least one head-up display area, and an apparatus for detecting window glass having at least one head-up display area.

[0002] Head-up display (HUD) systems for vehicles are well-known. These systems typically feature a head-up projector that projects light onto the windshield, where it is reflected back to create a virtual image in the driver's line of sight when viewed through the windshield. Therefore, when viewed from the eyebox position inside the vehicle, the virtual image appears in front of the driver and behind the windshield; the eyebox position indicates the driver's eye position.

[0003] A head-up display system is known for use on vehicle windshields, where a virtual image appears at a projection distance of approximately 1 to 3 meters (i.e., approximately 2 meters) from the eyepiece position. Such head-up display systems can be used to display basic information about the vehicle's condition, such as vehicle speed displayed in simple alphanumeric characters. In the prior art, such head-up display systems are commonly referred to as "conventional head-up display systems" or "conventional HUDs."

[0004] Recently, head-up displays (HUDs) have been developed to project more detailed information to drivers in the form of "augmented reality," where the information can be overlaid on a view of the real world. Typically, this type of augmented reality (or AR) HUD projects a larger area onto the windshield than the aforementioned conventional HUD systems. Furthermore, from the driver's perspective, the image appears much further behind the windshield, typically with a projection distance of approximately 10 meters from the viewpoint (compared to 1 to 2 meters for a conventional HUD).

[0005] WO2017 / 195026A2 describes a vehicle including a HUD system with an oblique or tilted image plane. In such a system, different portions of a route (i.e., for a given journey) can be displayed on the oblique or tilted image plane. For example, a first portion of the route can be projected at a first focal length, a second portion at a second focal length greater than the first focal length, and a third portion at a third distance greater than the second focal length. The focal length associated with the graphic overlay of the route can vary continuously between the first and third portions to provide a smooth continuum or gradient of the focal length associated with the route, comparable to the focal length of the real-world object corresponding to the route.

[0006] A similar system is described in WO2019 / 131296A1, see, for example, one of them. Figure 1And related descriptions. A HUD device is installed in a vehicle and displays an image as a virtual image on a virtual screen positioned in front of the windshield by projecting display light indicating the image onto the windshield. The HUD device is equipped with a display unit that emits display light; and a control unit that controls the image displayed on the virtual surface by controlling the operation of the display unit. The virtual surface is set to be tilted forward relative to the vertical direction of the vehicle.

[0007] To evaluate the performance of windshields used in head-up display systems for vehicles, they are typically tested before installation. Generally, light in the form of a matrix pattern is projected onto the windshield, and the image at the eyebox location (or several eye positions within the eyebox) is compared to predetermined head-up display performance parameters considered acceptable. Parameters such as ghosting, rotation, linear distortion, magnification, and aspect ratio can be determined.

[0008] In head-up display systems where the virtual image is 1 to 2 meters from the eyepiece, the optical setup required for detection and measurement is relatively simple because the virtual image is small and has low curvature. However, for head-up display systems where the virtual image is much farther from the eyepiece (i.e., about 5 to 10 meters or more, as is possible for AR HUDs), other factors such as image size and windshield curvature become more prominent due to the increased distance involved. The angular alignment of the optical elements in the detection system also becomes more critical due to the increased distance to the virtual image.

[0009] US11,340,453B2 discusses how, in augmented reality HUD systems, the significantly expanded image size and curvature can cause parts of the image to consistently appear out of focus due to the limited depth of focus of the camera unit used during detection. Problems caused by astigmatism are also discussed.

[0010] The present invention aims to provide at least one alternative method for detecting a vehicle windshield having a head-up display area, particularly for a head-up display area used in an augmented reality head-up display system.

[0011] Accordingly, from a first aspect, the present invention provides a method for detecting a window glass configured for installation in a vehicle having a head-up display projector, such that, in use, light from the head-up display projector illuminates a first head-up display area of ​​the window glass to generate a first virtual image at a first projection distance from an eyepiece position. The method for detecting the window glass includes: (i) positioning the window glass relative to a light source; (ii) directing light from the light source to illuminate at least a portion of the first head-up display area of ​​the window glass, thereby generating a first virtual image at a first image plane at a first distance from the eyepiece position; (iii) imaging the first virtual image at the first image plane using an imaging system to capture a first image; and (iv) using the first image of the first virtual image at the first image plane to determine at least a first performance parameter of the first head-up display area of ​​the window glass, wherein the first distance is different from the first projection distance.

[0012] The inventors have discovered that by measuring the virtual image located at a first image plane at a first distance from the eyepiece position, the performance of the window glass at a first projection distance can be accurately evaluated, wherein the first distance is different from the first projection distance of the first head-up display area when the window glass is installed in a vehicle.

[0013] When this portion of the first head-up display area is illuminated during (ii), a first virtual image is generated at a first image plane at a first distance from the eyepiece position, rather than at a first projection distance from the eyepiece position. This allows for detection measurements to be performed only at the first image plane to determine performance parameters for different areas of the windshield, which, when installed in a vehicle, might be head-up display areas with different projection distances. While the performance parameters measured at the first distance are not necessarily the same as those measured at the first projection distance, the inventors have surprisingly found a good correlation between the performance parameter measurements performed at the first distance and those performed at the first projection distance.

[0014] Preferably, the first performance parameter determined at (iv) is compared with an appropriate performance specification. The appropriate performance specification is preferably a range of the first performance parameter at a first distance. For example, if the performance parameter value at (iv) is determined to be P1, then the performance specification may specify that P1 can vary between P1-Δp1 and P1+Δp2. Such performance specifications may differ for window glass intended for use in different vehicles.

[0015] Preferably, the first performance parameter of the first head-up display area of ​​the window glass is related to ghosting, distortion, magnification, aspect ratio, or displacement.

[0016] Preferably, the first projection distance is greater than 3m, more preferably greater than 5m, and even more preferably greater than 7m.

[0017] Preferably, the first projection distance is less than 150m, more preferably less than 50m, even more preferably less than 20m, and even more preferably less than 15m.

[0018] Preferably, the first distance is less than or equal to about 4m.

[0019] Preferably, the first distance is less than or equal to about 3m.

[0020] Preferably, the first distance is less than or equal to about 2.5m.

[0021] Preferably, the first distance is greater than about 0.5m, more preferably greater than about 1m.

[0022] Preferably, the first projection distance is between 7m and 150m, and the first distance is between 1m and 30m, provided that the first distance is less than the first projection distance.

[0023] Preferably, the first projection distance is between 7m and 15m, and the first distance is between 1m and 3m.

[0024] Preferably, the first head-up display area is used for an augmented reality head-up display system.

[0025] Preferably, the first head-up display area is at least 5% of the area of ​​the window glass.

[0026] Preferably, the first head-up display area is less than about 50% of the area of ​​the window glass, more preferably less than about 25% of the area of ​​the window glass.

[0027] Preferably, the window glass is a windshield.

[0028] Preferably, the window glass is a windshield for motor vehicles, trains, airplanes, or vehicles used on water.

[0029] Preferably, the window glass includes a first window glass material pane joined to a second window glass material pane by a sandwich structure comprising at least one piece of adhesive interlayer material, the second window glass material pane being an inner panel facing the interior of the vehicle when the window glass is installed in the vehicle, and the first window glass material pane being an outer panel facing the exterior environment when the window glass is installed in the vehicle; wherein when the window glass is installed in the vehicle, the inner panel has a main surface facing the interior of the vehicle, and wherein the outer panel has an outer surface facing the exterior environment of the vehicle in which the window glass is installed.

[0030] Preferably, the imaging system includes at least one camera.

[0031] Preferably, the imaging system includes at least one fixed camera for capturing an image of the first virtual image from a corresponding fixed eye position in the eyebox.

[0032] Preferably, the imaging system includes at least one movable camera for capturing an image of a first virtual image from a first eye position in the eye box, the movable camera being movable to a second eye position in the eye box to capture different images of the first virtual image.

[0033] Preferably, the first image of the first virtual image is captured when the camera is positioned at the eye box location.

[0034] Preferably, the first image of the first virtual image is captured when the camera is positioned at the first eye position in the eyebox.

[0035] Preferably, the eye box location has more than one eye position associated with it.

[0036] Preferably, the light source includes a display.

[0037] Preferably, the light source comprises a perforated pattern illuminated by a planar light source backlight.

[0038] Preferably, the first virtual image at the first distance is configured as the first virtual image at the first projection distance parallel to the head-up display system.

[0039] Preferably, the first virtual image at the first distance is configured to be parallel to the position of the eye box.

[0040] In some embodiments, the first virtual image at a first projection distance is part of a tilted virtual image, wherein the tilted virtual image is tilted relative to the eye box position. WO2019 / 131296A1 describes a vehicle having such a HUD system, wherein the virtual image is displayed on a virtual surface that is configured to tilt forward relative to the vertical direction of the vehicle.

[0041] Preferably, the first virtual image at the first projection distance is part of a tilted virtual image, which is set to tilt forward relative to the vertical direction of the vehicle, i.e., along the forward travel direction of the vehicle.

[0042] In some embodiments, the first distance is less than the first projection distance.

[0043] Preferably, the first projection distance is greater than xm, where x = 3, or 4, or 5, or 6, or 7, or 8, or 9, or 10, or 15, or 20, or 30, or 40, or 50, or 60, or 70, or 80, or 90, or 100.

[0044] Preferably, the first projection distance is less than ym, where y = 110, or 100, or 90, or 80, or 70, or 60, or 50, or 40, or 30.

[0045] Preferably, the first projection distance is between 5m and 15m.

[0046] Preferably, the first distance is no greater than jm, where j = 5, or 4.5, or 4, or 3.5, or 3, or 2.5, or 2, or 1.5, or 1, or 0.5.

[0047] Preferably, the first distance is at least km, where k = 0.1, or 0.2, or 0.3, or 0.4, or 0.5, or 0.6, or 0.7, or 0.8, or 0.9, or 1, or 1.1, or 1.2, or 1.3, or 1.4, or 1.5, or 1.6, or 1.7, or 1.8, or 1.9, or 2.

[0048] Preferably, the first distance is between 0.5m and 5m, more preferably between 0.5m and 4m, and even more preferably between 0.5m and 3m.

[0049] In some embodiments, the first distance is greater than the first projection distance.

[0050] Preferably, the first distance is greater than x'm, where x' = 3, or 4, or 5, or 6, or 7, or 8, or 9, or 10, or 15, or 20, or 30, or 40, or 50, or 60, or 70, or 80, or 90, or 100.

[0051] Preferably, the first distance is less than y'm, where y' = 110, or 100, or 90, or 80, or 70, or 60, or 50, or 40, or 30.

[0052] Preferably, the first distance is between 5m and 15m.

[0053] Preferably, the first projection distance is less than or equal to j'm, where j' = 5, or 4.5, or 4, or 3.5, or 3, or 2.5, or 2, or 1.5, or 1, or 0.5.

[0054] Preferably, the first projection distance is at least k'm, where k' = 0.1, or 0.2, or 0.3, or 0.4, or 0.5, or 0.6, or 0.7, or 0.8, or 0.9, or 1, or 1.1, or 1.2, or 1.3, or 1.4, or 1.5, or 1.6, or 1.7, or 1.8, or 1.9, or 2.

[0055] Preferably, the first projection distance is between 0.5m and 5m, more preferably between 0.5m and 4m, and even more preferably between 0.5m and 3m.

[0056] In some embodiments, the first projection distance is greater than 20m.

[0057] Preferably, the first projection distance is greater than x'' m, where x'' = 30, or 40, or 50, or 60, or 70, or 80, or 90, or 100.

[0058] Preferably, the first projection distance is less than y'' m, where y'' = 110, or 100, or 90, or 80, or 70, or 60, or 50, or 40, or 30.

[0059] In some embodiments, the first image of the first virtual image is captured when the imaging system is positioned at the eyebox location.

[0060] Preferably, the first image of the first virtual image is captured when the camera is positioned at the eyebox location.

[0061] Preferably, the first image of the first virtual image is captured with the camera positioned at the first eye position within the eyebox.

[0062] In some embodiments, the first image of the first virtual image is captured at the first eye position in the eyebox.

[0063] Preferably, the method includes capturing a second image of a first virtual image at a second eye position in the eyebox at a first image plane, and using the second image of the first virtual image to determine a first performance factor.

[0064] In some embodiments, multiple images of the first virtual image are captured, each image being captured at a different eye position within the eyebox.

[0065] Preferably, each of the multiple images is used to determine a corresponding first performance parameter.

[0066] Preferably, each image is used to construct the first virtual image, and the constructed first virtual image is used to determine the first performance parameter.

[0067] In some embodiments, the window glass includes a first window glass material pane joined to a second window glass material pane by a sandwich structure comprising at least one piece of adhesive interlayer material, the second window glass material pane being an inner panel facing the interior of the vehicle when the window glass is installed in the vehicle, the inner panel having an inner surface facing the interior of the vehicle when the window glass is installed in the vehicle, wherein the resulting first virtual image includes light reflected from at least the inner surface of the inner panel.

[0068] In these embodiments, the first window glass material pane is an outer panel of the vehicle in which the window glass is installed, facing outwards, wherein the outer panel has an outer surface of the vehicle in which the window glass is installed, facing outwards.

[0069] Preferably, the generated first virtual image comprises light reflected from at least the sandwich structure.

[0070] Preferably, in these embodiments, the first virtual image produced comprises light reflected from at least the outer surface. The reflection of light from the inner and outer surfaces can be used to determine performance parameters related to ghosting.

[0071] In some embodiments, the imaging system includes a first camera located at a first eye position in the eye box to capture a first image of the first virtual image, and a second camera located at a second eye position in the eye box to capture a second image of the first virtual image.

[0072] In some embodiments, the imaging system may be movable relative to the window glass to capture a first image when the imaging system is in a first position relative to the window glass, and to capture a second image when the imaging system is in a second position relative to the window glass. The imaging system may be movable, such as a robotic arm.

[0073] When the imaging system is in a first position relative to the window glass, the first image is preferably captured at a first eye position in the eye box.

[0074] When the imaging system is movable and moved to a second position relative to the window glass, the second image is preferably captured at the second position in the eye box.

[0075] In embodiments where the imaging system is movable relative to the window glass, it is preferable to capture multiple images to construct an image of the entire first virtual image.

[0076] In some embodiments, the light from the light source is in the form of a pattern, preferably including at least one point and / or at least one line.

[0077] Preferably, the pattern is specific to the inspection of window glass intended for use in a particular model of vehicle.

[0078] In some embodiments, the light from the light source is in the form of a pattern, and a first virtual image of the pattern at a first image plane is distorted by the window glass, wherein, when determining the performance parameters of the window glass, the first virtual image distorted by the window glass is compared with a reference image or reference pattern of the pattern.

[0079] As is known in the art, a reference image or reference pattern may be an undistorted image that is then distorted to be projected onto the window glass being inspected.

[0080] In some embodiments, the first performance parameter of the first head-up display area of ​​the window glass is determined using only a first image of the first virtual image.

[0081] In such embodiments, the first image of the first virtual image is preferably captured when the imaging system is positioned at the first eye position in the eye box.

[0082] In some embodiments, during (ii), light from the light source illuminates at least the entire first head-up display area.

[0083] Preferably, at (iii), the entire first virtual image from the fully illuminated first head-up display area is imaged, and the captured first image is an image of the entire first virtual image.

[0084] Preferably, at (iii), only a portion of the entire virtual image from the fully illuminated first head-up display area is captured as the first image.

[0085] Preferably, the image of the entire virtual image from the first head-up display area is constructed from multiple images, each of which has a different portion of the entire virtual image from the first head-up display area. The multiple images can be captured using an imaging system located at different eye positions within the eye box, preferably comprising at least one camera that can be fixed or movable.

[0086] In some embodiments, the performance of the entire first head-up display area is determined by performing steps (ii) and (iii) multiple times to illuminate multiple different portions of the first head-up display area of ​​the window glass.

[0087] Preferably, each portion of the first head-up display area is individually illuminated.

[0088] Preferably, each different part is used to determine the corresponding first performance parameter.

[0089] Preferably, each corresponding first image from a different illuminated portion of the first head-up display area is used to construct an image of the entire virtual image from the first head-up display area. The image of the entire virtual image from the first head-up display area thus constructed can then be used to determine first performance parameters of the first head-up display area of ​​the window glass.

[0090] In some embodiments, the window glass is configured for installation in a vehicle such that, in use, light from a head-up display projector illuminates a second head-up display area of ​​the window glass to produce a virtual image at a second projection distance from the eyepiece location, wherein the second projection distance is less than a first projection distance.

[0091] Preferably, the method for detecting the window glass includes detecting a second head-up display area to determine at least a first performance parameter of the second head-up display area of ​​the window glass.

[0092] Preferably, the method for detecting the second head-up display area includes: directing light from the light source or another light source to illuminate at least a portion of the second head-up display area of ​​the window glass, thereby generating a second virtual image at a second image plane located at a second distance from the eye box position; imaging the second virtual image at the second image plane using an imaging system to capture a first image of the second virtual image; and using the first image of the second virtual image to determine at least a first performance parameter of the second head-up display area of ​​the window glass.

[0093] Preferably, the first performance parameter of the second head-up display area of ​​the window glass is compared with an appropriate performance specification.

[0094] Preferably, the second distance between the second image plane and the eye box position is the same as the first distance between the first image plane and the eye box position.

[0095] Preferably, the second distance is the same as the second projection distance.

[0096] Preferably, the first projection distance is between 5m and 20m, and the second projection distance is between 1m and 5m.

[0097] Preferably, the first head-up display area of ​​the window glass has a first area, and the second head-up display area of ​​the window glass has a second area, wherein the first area is larger than the second area.

[0098] Preferably, the first area is at least 1.5 times the area of ​​the second area, more preferably 2 times the area of ​​the second area, and even more preferably 3, 4, 5, 6, 7, 8, 9, or 10 times the area of ​​the second area.

[0099] Preferably, the first area is less than 20 times the area of ​​the second area.

[0100] Preferably, the first area is used for an augmented reality head-up display system, and the second area is used for a conventional head-up display system.

[0101] In some embodiments, the method is used to detect a window glass configured for installation in a vehicle, such that, in use, light from a head-up display projector illuminates a second head-up display area of ​​the window glass to generate a second virtual image at a second projection distance from the eyepiece position, wherein the second projection distance is greater than the first projection distance.

[0102] Preferably, the method for detecting the window glass includes detecting a second head-up display area to determine at least a first performance parameter of the second head-up display area of ​​the window glass.

[0103] Preferably, the method for detecting the second head-up display area includes: directing light from the light source or another light source to illuminate at least a portion of the second head-up display area of ​​the window glass, thereby generating a second virtual image at a second image plane located at a second distance from the eye box position; imaging the second virtual image at the second image plane using an imaging system to capture a first image of the second virtual image; and using the first image of the second virtual image to determine at least a first performance parameter of the second head-up display area of ​​the window glass.

[0104] Preferably, the first performance parameter of the second head-up display area of ​​the window glass is compared with an appropriate performance specification.

[0105] Preferably, the second distance between the second image plane and the eyepiece position is the same as the first distance between the first image plane and the eyepiece position. This provides the advantage that the first parameters of the first and second head-up display areas of the window glass can be measured using the same optical arrangement, thereby speeding up the detection process.

[0106] Preferably, the first distance is the same as the second projection distance.

[0107] In some embodiments, the method includes a calibration step such that during (iv), a first performance parameter measured at a first image plane can be transformed into a corresponding first performance parameter at a first projection distance from the eyebox location or at another projection distance using at least a first correction factor determined during the calibration step.

[0108] Preferably, the first correction factor is determined using measurements or ray tracing of a first performance parameter of a reference virtual image generated at a first image plane and a first projection distance or another distance.

[0109] By determining an appropriate correction factor between the first performance parameters at different distances from the eyebox location (such as a first distance and a first projection distance), the performance parameters can be measured at a first image plane at a first distance from the eyebox location, and the performance parameters at a first portion of the distance can be calculated. This would be useful if the actual performance parameters at the first projection distance were required.

[0110] Preferably, the first correction factor includes a factor for transforming at least one of ghosting, distortion, magnification, aspect ratio, and displacement.

[0111] In some embodiments, the head-up display projector includes at least a first projector for generating light to illuminate a first head-up display area of ​​the window glass.

[0112] In some embodiments, when the window glass is installed in the vehicle, the eye box is in a standard position and can be moved to a higher or lower position depending on the height of the vehicle's driver.

[0113] In an embodiment where the window glass has a first head-up display area and a second head-up display area, preferably, the head-up display projector includes a first projector for generating light to illuminate the first head-up display area of ​​the window glass, and a second projector for generating light to illuminate the second head-up display area of ​​the window glass.

[0114] Preferably, the first projector and the second projector are installed in the same housing.

[0115] The invention also provides, in a second aspect, an apparatus for detecting window glass configured for installation in a vehicle having a head-up display projector, such that, in use, light from the head-up display projector illuminates a first head-up display area of ​​the window glass to generate a first virtual image at a first projection distance from an eyepiece location; the apparatus includes: a clamp, a light source, an imaging system, and a computer; the clamp is arranged relative to the light source and configured to hold the windshield during a detection measurement such that light from the light source illuminates the window glass to generate a virtual image at a first image plane located at a first distance from the eyepiece location; the imaging system is arranged relative to the window glass during the detection step to capture an image of the virtual image at the first image plane through the window glass; and wherein the computer has a program for analyzing the captured image of the virtual image at the first image plane to determine at least a first performance parameter of the window glass, wherein the first image plane is located at a position different from the first projection distance.

[0116] Preferably, the imaging system is positioned at the eye box location.

[0117] Embodiments of the invention will now be described by way of example only and with reference to the accompanying drawings (not to scale), in which:

[0118] Figure 1 A schematic plan view of a vehicle windshield with a head-up display area is shown;

[0119] Figure 2 It shows Figure 1 A schematic side view diagram showing the installation of a vehicle's windshield in the vehicle.

[0120] Figure 3 A schematic side view of an apparatus for performing the method according to the first aspect of the invention is shown;

[0121] Figure 4 A comparison is shown between the measured height of a virtual image element at a first image plane and the measured height of a virtual image element at a second image plane different from the first image plane;

[0122] Figure 5 A comparison is shown between the area of ​​the illuminated windshield and the area of ​​the first head-up display area; and

[0123] Figure 6The area of ​​the six images captured to construct the entire virtual image produced by the illumination of the first head-up display area by the light source is shown.

[0124] Figure 1 A plan view of a vehicle windshield 1 with a first head-up display area 3 is shown. In this example, the first head-up display area is used for the vehicle's augmented reality head-up display system, where a virtual image is generated behind the windshield at a distance of approximately 10m from the driver's viewpoint.

[0125] In this example, the first head-up display area 3 is displayed as a rectangle, but it could also be other shapes, such as a trapezoidal perimeter.

[0126] Figure 2 The illustration shows a schematic side view of a windshield 1 mounted in a vehicle (not shown) at an angle 7 relative to the vertical. In use, a suitable head-up display projector 9 (which may include more than one projector system) illuminates a first head-up display area 3. At eye-box position 11, when viewed through the windshield 1, the driver sees a first virtual image 15 at a first projection distance 19 from eye-box position 11. The first virtual image 15 at the first projection distance 19 from eye-box position 11 may be referred to as the first virtual image in use or the first virtual image in the vehicle.

[0127] As is known in the art, the eye box position can be moved up and down relative to a standard position to accommodate drivers of different heights, thereby ensuring that the driver's eyes are positioned within the eye box.

[0128] For augmented reality head-up display systems, the first projection distance 19 is typically greater than about 5m, typically about 5m–20m or about 7m–15m, or about 8m–12m, or about 10m.

[0129] A windshield 1 is typically made of two glass panes laminated together by a sandwich structure containing at least one adhesive interlayer material, such as polyvinyl butyral (PVB). The adhesive interlayer material used for windshields with head-up displays is typically wedge-shaped to reduce ghosting caused by reflections from the inner and outer surfaces of the windshield.

[0130] As is customary in the art, glass sheets are typically about 1-3 mm thick, and PVB sheets are about 0.76 mm thick. The glass can be soda-lime silicate glass, with a composition similar to clear float glass, and often has iron oxide added as a colorant to provide some form of sunlight control to the laminated window glass.

[0131] The total thickness of a windshield is usually less than 6mm.

[0132] A typical soda-lime silicate glass composition (by weight) is: SiO2 69–74%; Al2O3 0–3%; Na2O 10–16%; K2O 0–5%; MgO 0–6%; CaO 5–14%; SO3 0–2%; Fe2O3 0.005–2%. The glass composition may also contain other additives, such as refining aids, which are typically present in amounts up to 2%. Soda-lime silicate glass compositions may also contain other colorants, such as Co3O4 and Se, to impart the desired color when the glass is viewed under transmitted light. The color of the transmitted glass can be measured according to recognized standards such as BS EN410.

[0133] Other glass compositions are known in the art for use as inner or outer panels of laminated window glass for vehicle windshields, such as aluminosilicate glass. These glass panels are typically used in thicknesses less than 1 mm, for example, between 0.2 mm and 0.9 mm, and may be chemically strengthened.

[0134] As is customary in the art, the glass panel facing the external environment is generally referred to as the outer glass panel, and the glass panel facing the vehicle interior is generally referred to as the inner glass panel. Each of the inner and outer glass panels has a first primary surface and a corresponding opposing second primary surface, and when the windshield is arranged such that the second primary surface of the outer glass panel faces the first primary surface of the inner glass panel (the inner and outer glass panels are joined together by a PVB sheet), the first primary surface of the outer glass panel is generally referred to as "surface one", the second primary surface of the outer glass panel is referred to as "surface two", the first primary surface of the inner glass panel is referred to as "surface three", and the second primary surface of the inner glass panel is referred to as "surface four".

[0135] As is obvious, “Surface 1” is the outer surface (or outward-facing surface) of windshield 1, and “Surface 4” is the inner surface (or inward-facing surface) of windshield 1.

[0136] Vehicle windshields are typically curved in one or more directions. The radius of curvature in one or more directions can be between 1000 mm and 8000 mm.

[0137] When a vehicle windshield is curved in two directions, each direction of curvature is appropriately orthogonal to the others. Appropriately, the radius of curvature in one or both directions is between 1000 mm and 8000 mm.

[0138] Typically, "surface one" of a vehicle's windshield is convex, while "surface four" is concave.

[0139] exist Figure 2 In the middle, the windshield 1 has an inward-facing surface 4, that is, the "surface four" of the windshield.

[0140] Typically, light from the head-up display projector 9 is reflected from a portion of the inward-facing surface 4 defining the first head-up display area 3 toward the eye-box location 11 to produce a virtual image that appears to be behind the windshield (from the driver's perspective). In some embodiments, the virtual image may be produced at least partially by reflection from any other "surface one," "surface two," or "surface three" of the windshield. In some windshields, the sandwich structure joining the two glass panels together may be suitably configured to allow some light from the display projector 9 to be directed toward the eye-box location 11. This may coexist with, or replace, any light reflected from any of the surfaces "surface one," "surface two," "surface three," or "surface four."

[0141] To evaluate the image quality of the first head-up display area 3, the windshield is typically inspected before installation in the vehicle. For a standard head-up display area, a light source illuminates the windshield to generate a virtual image corresponding to the head-up display image at the projection distance of the virtual image when the windshield is installed in the vehicle. The display image is typically in the form of a characteristic pattern of dots and lines, which is distorted so that an undistorted virtual image is produced when reflected off the curved inner surface of the windshield. This virtual image is captured through the windshield from multiple possible eye positions of the driver (i.e., different eye positions within the eye box) using a camera unit. Using these images, the occurrence of optical effects such as distortion and ghosting due to multiple reflections can then be estimated in detail for different eye positions within the eye box.

[0142] When capturing virtual images from different eye positions within an eyebox using a camera unit, a single camera can be movably mounted, for example, on a robotic arm, to move the camera between different eye positions. Alternatively, multiple cameras can be used, each associated with a single eye position. Movement during testing is then unnecessary, and therefore the cameras are preferably statically mounted.

[0143] The images captured by the camera, or each camera, are then analyzed using image processing procedures well-known in the art to determine specific performance parameters of the first head-up display area of ​​the windshield at the corresponding eye position within the eye box. This is often simply referred to as the windshield's performance parameters. Overall specific performance parameters can be determined based on each specific performance parameter at the corresponding eye box position.

[0144] Figure 3 This describes how to perform the method according to the first aspect of the invention.

[0145] For reference Figure 1 and Figure 2 The windshield 1 is to be tested to evaluate its head-up display performance in an augmented reality head-up display system used in a vehicle, wherein the virtual image has a first projection distance of approximately 10m from the eye box position. Figure 3In the middle, align axis A-A' with the position of the eye box, and refer to... Figure 2 The first projected distance is displayed as a distance of 19.

[0146] The windshield 1 is held in the desired inspection position by a suitable clamp 39. The clamp 39 ensures that all measurements are performed while the windshield 1 (and subsequent windshields to be inspected) are held in the same desired measurement position.

[0147] The light source 9' is positioned to guide the light in the direction of arrow 10' to illuminate the first head-up display area 3 of the windshield 1.

[0148] Light from light source 9' is reflected from the windshield 1 toward camera 35. Camera 35 is positioned at the eye position within the eye box. Virtual image 13 is generated by light from light source 9' illuminating the inward-facing surface 4, and virtual image 13 can be imaged by camera 35. Virtual image 13 is generated at a first image plane, which is a first distance 17 from the eye box, the first distance 17 being less than a first projection distance 19.

[0149] The light from light source 9' is in the form of a pattern consisting of multiple points, and... Figure 3 In this context, camera 35 is shown as imaging a point 41. Point 41 can be referred to as a virtual image element.

[0150] For reference purposes only. Figure 3 The image shows the position of the virtual image 15 at a first projection distance of 19 from the eye box position. The corresponding virtual image element point 41 (marked as point 41' in the virtual image 15) is also shown.

[0151] According to the detection method of the present invention, a virtual image 13 at a first distance 17 is imaged. This first distance 17 is different from the first projection distance 19, and in this embodiment, the first distance 17 is smaller than the first projection distance 19. Figure 3 As shown, the windshield 1 is detected using a virtual image 13, as shown in the image. Figure 2 Compared to the virtual image 15 generated when the windshield 1 is installed in the vehicle, the virtual image 13 is not in the same position relative to the windshield 1, even though the same head-up display area 3 is illuminated to generate the virtual images 13 and 15.

[0152] The light projected onto the first head-up display area 3 is in the form of a distorted reference image (or pattern). The amount of distortion applied to the reference image can be determined in part based on the geometry of the windshield and / or any other optical components used to project light from the light source 9' onto the first head-up display area 3. Since the projected image is reflected from the inward-facing surface 4 of the windshield 1, the distorted projected image itself is distorted, and the virtual image 13 produced at the first image plane is ideally identical to the original undistorted reference image. By evaluating the degree to which the virtual image deviates from the undistorted reference image, the performance parameters of the windshield can be determined against a set of predetermined standards or applicable performance specifications.

[0153] According to an embodiment of the present invention, the first distance 17 during the detection period of the windshield 1 is less than the first projection distance 19. In this example, the first projection distance 19 is approximately 10m, and the first distance 17 is approximately 2m.

[0154] Surprisingly, the inventors discovered a strong correlation between the performance parameters determined by measurements taken from a first distance 17 and the corresponding performance parameters determined by measurements taken from a first projection distance 19. This correlation allows for the definition of performance specifications for the performance parameters of the first head-up display area of ​​the windshield, determined by measurements taken from the first distance (rather than the first projection distance). This eliminates the need for measurements at the first projection distance, thus simplifying the inspection process, as measurements only need to be taken at a first distance that may be much shorter than the first projection distance.

[0155] To illustrate the correlation between the performance parameters measured when a virtual image is generated at approximately 2m and those measured when a virtual image is generated at approximately 10m, refer to... Figure 4 .

[0156] Figure 4 The diagram shows how the measured height of a virtual image element in a virtual image at a projection distance of approximately 10m (axis 31) is compared with the measured height of the corresponding virtual image element in a virtual image at a projection distance of approximately 2m (axis 33).

[0157] As can be seen, a good correlation exists. This allows for the definition of appropriate performance specifications at a distance of 2m (i.e., the first distance) to evaluate the quality of the window glass. This correlation also allows for the determination of equations or correction factors to transform the height of the virtual image element measured at the first image plane to a calculated height at the second image plane (which may be at the first projection distance). If this is desired, then the performance specifications can be based on the transformed performance parameters at the second distance (which may be the projection distance), rather than the measured performance parameters at the first distance.

[0158] Back Figure 3 The camera 35 communicates with the computer 38 via a suitable cable 38a.

[0159] The computer 38 can also communicate with the light source 9' via a suitable cable 38b to control the pattern projected onto the inward-facing surface 4 of the windshield 1. Different patterns can be used for windshields of different types of vehicles.

[0160] Computer 38 includes software for analyzing images of the virtual image 13 captured by camera 35 to determine specific performance parameters of the head-up display area 3 of the windshield 1. These parameters are then compared with performance specifications of the specific performance parameters at a first distance 17 to determine whether the windshield 1 has acceptable performance for use in a head-up display system in a suitable vehicle.

[0161] Camera 35 can capture one or more images of the virtual image 13 at the first image plane to image the entire virtual image generated by light reflected from the entire first head-up display area 3. Camera 35 can be positioned at different eye positions within the eye box to capture an image at each eye position. The images captured at each eye position within the eye box can then be used to determine specific performance parameters at each corresponding eye box location. (Reference) Figure 5 and Figure 6 To further illustrate this point.

[0162] refer to Figure 3 , Figure 5 and Figure 6 In order to measure the performance of the first head-up display area 3 of the windshield 1, at least the entire first head-up display area 3 is illuminated by light from the light source 9'. In this example, the perimeter of the illuminated area is shown by the dashed line 21 and includes the entire first head-up display area 3.

[0163] Measurements taken by camera 35 of the virtual image 13 at the first image plane can be a single captured image. However, due to the size of the virtual image 13 at the first image plane, multiple images are typically captured using a suitable imaging system, which may include multiple cameras at different eye positions within the eye box and / or a movable camera for moving to each eye position within the eye box. In this example, camera 35 is movable to six different eye positions within the eye box and is used to capture six images 25a, 25b, 25c, 25d, 25e, and 25f. Instead of the movable camera, six fixed cameras at the desired eye positions within the eye box could be used to capture images 25a, 25b, 25c, 25d, 25e, and 25f.

[0164] For a specific performance parameter, each individual image 25a, 25b, 25c, 25d, 25e, and 25f can be used to determine the corresponding specific performance parameter for that part of the virtual image.

[0165] The six images 25a, 25b, 25c, 25d, 25e, and 25f allow the construction of the entire virtual image produced by reflections from the entire first head-up display area 3.

[0166] If desired, performance parameters can also be determined using an image constructed from the entire virtual image generated by reflections from the entire first head-up display area 3.

[0167] The method according to the invention can also be used to inspect window glass with two (or more) head-up display areas, such as vehicle windshields. When the window glass is installed in a vehicle, performance parameters of different head-up display areas can be measured using virtual images generated at the same distance from the eyepiece position for each different head-up display area. This requires appropriate illumination of the different head-up display areas to generate virtual images at the same distance relative to the eyepiece position for measurement of each different head-up display area, where each different head-up display area has a corresponding projection distance when the window glass is installed in a vehicle.

[0168] According to the present invention, such window glass can be detected without using a virtual image projected at a projection distance in any head-up display area.

[0169] For example, if a windshield has a first head-up display area for an augmented reality head-up display system (where the projection distance can be about 10m from the eye box position) and a second head-up display area for a conventional head-up display system (where the projection distance can be about 2m from the eye box position), then according to the present invention, the performance parameters of the second head-up display area of ​​the window glass can be made using a virtual image generated at 2m, and the performance parameters of the first head-up display area of ​​the window glass can also be made using a virtual image generated at 2m.

[0170] Although the performance parameters of the first head-up display area measured using a virtual image at 2m (instead of 10m) differ from the equivalent performance parameters measured at 10m, as... Figure 4 As shown, there is a good correlation, which allows for the determination of appropriate performance specifications for the performance parameters of the first head-up display area when using a virtual image at 2m (instead of 10m).

[0171] By using a suitable virtual image 2m away from the eye box, the performance parameters of the second head-up display area are obtained at the projection distance of a conventional head-up display system, which is desirable.

[0172] However, it is anticipated that the performance parameters of the second head-up display area can be obtained using virtual images at different distances from the eye box position, such as 1m or greater than 2m but less than the projection distance of the augmented reality head-up display system (i.e., 10m). As the distance of the virtual image used in the method according to the invention approaches the projection distance of the augmented reality head-up display system, the advantages of the invention may diminish.

[0173] When using the present invention to detect a window having at least first and second head-up display areas (each having a corresponding projection distance from the eye box position, wherein the projection distance of the first head-up display area is greater than the projection distance of the second head-up display area), it is advantageous to use a virtual image located at or less than the projection distance of the second head-up display area to detect the window. This is particularly advantageous when the projection distance of the first head-up display area is greater than 5m and less than 20m, and when the projection distance of the second head-up display area is less than 5m and greater than 1m.

[0174] In other embodiments of the invention, the windshield just defined above, having a first head-up display area (with a projection distance of approximately 10m from the eye-box position) for an augmented reality head-up display system and a second head-up display area (with a projection distance of approximately 2m from the eye-box position) for a conventional head-up display system, can be detected using a virtual image generated at an image plane greater than 10m from the eye-box position. However, this is not preferred because the previously discussed difficulties arise as the virtual image becomes farther away from the eye-box position.

[0175] It will be clear that the method according to the invention can be used to detect window glass having more than two head-up display areas (such as three or more head-up display areas).

[0176] The present invention has the following aspects.

[0177] Aspect 1. A method for detecting a window glass configured for installation in a vehicle having a head-up display projector, such that, in use, light from the head-up display projector illuminates a first head-up display area of ​​the window glass to generate a first virtual image at a first projection distance from an eyepiece location, the method comprising: (i) positioning the window glass relative to a light source; (ii) directing light from the light source to illuminate at least a portion of the first head-up display area of ​​the window glass to generate a first virtual image at a first image plane at a first distance from the eyepiece location; (iii) imaging the first virtual image at the first image plane using an imaging system to capture a first image; and (iv) using the first image of the first virtual image at the first image plane to determine at least a first performance parameter of the first head-up display area of ​​the window glass; wherein the first distance is different from the first projection distance.

[0178] Aspect 2. According to the method of aspect 1, the first performance parameter determined at (iv) is compared with the appropriate performance specification.

[0179] Aspect 3. According to the method of aspect 2, the appropriate performance specification is the range of the first performance parameter at the first distance.

[0180] Aspect 4. The method according to any one of aspects 1 to 3, wherein the first projection distance is greater than 3m, more preferably greater than 5m, and even more preferably greater than 7m.

[0181] Aspect 5. The method according to any one of aspects 1 to 4, wherein the first projection distance is less than 150m, more preferably less than 50m, even more preferably less than 20m, even more preferably less than 15m.

[0182] Aspect 6. The method according to any one of aspects 1 to 5, wherein the first distance is less than or equal to about 4m, preferably wherein the first distance is less than or equal to about 3m, more preferably wherein the first distance is less than or equal to about 2.5m.

[0183] Aspect 7. The method according to any one of aspects 1 to 6, wherein the first distance is greater than about 0.5 m, preferably greater than about 1 m.

[0184] Aspect 8. The method according to any one of Aspects 1 to 7, wherein the first projection distance is between 7m and 150m, and the first distance is between 1m and 30m, provided that the first distance is less than the first projection distance.

[0185] Aspect 9. The method according to any one of aspects 1 to 8, wherein the first projection distance is between 7m and 15m, and the first distance is between 1m and 3m.

[0186] Aspect 10. The method according to any one of aspects 1 to 9, wherein the first head-up display area is used for an augmented reality head-up display system.

[0187] Aspect 11. The method according to any one of aspects 1 to 10, wherein the first head-up display area is at least 5% of the area of ​​the window glass.

[0188] Aspect 12. The method according to any one of aspects 1 to 11, wherein the first head-up display area is less than about 50% of the area of ​​the window glass, preferably less than about 25% of the area of ​​the window glass.

[0189] Aspect 13. The method according to any one of aspects 1 to 12, wherein the window glass is a windshield.

[0190] Aspect 14. The method according to any one of Aspects 1 to 13, wherein the window glass is a windshield for a motor vehicle, train, airplane or vehicle used on water.

[0191] Aspect 15. The method according to any one of aspects 1 to 14, wherein the window glass includes a first window glass material pane joined to a second window glass material pane by a sandwich structure comprising at least one piece of adhesive interlayer material, the second window glass material pane being an inner panel facing the interior of the vehicle when the window glass is installed in the vehicle, and the first window glass material pane being an outer panel facing the exterior environment when the window glass is installed in the vehicle; wherein when the window glass is installed in the vehicle, the inner panel has a main surface facing the interior of the vehicle, and wherein the outer panel has an outer surface facing the exterior environment of the vehicle in which the window glass is installed.

[0192] Aspect 16. The method according to any one of aspects 1 to 15, wherein the imaging system includes at least one camera.

[0193] Aspect 17. The method according to any one of aspects 1 to 16, wherein the imaging system includes at least one fixed camera for capturing an image of the first virtual image from a corresponding fixed eye position in the eyebox.

[0194] Aspect 18. The method according to any one of aspects 1 to 17, wherein the imaging system includes at least one movable camera for capturing an image of a first virtual image from a first eye position in an eye box, the movable camera being movable to a second eye position in the eye box to capture different images of the first virtual image.

[0195] Aspect 19. The method according to any one of aspects 1 to 18, wherein the first image of the first virtual image is captured by a camera positioned at the eye box location.

[0196] Aspect 20. The method according to any one of aspects 1 to 19, wherein the first image of the first virtual image is captured by a camera positioned at a first eye position in the eyebox.

[0197] Aspect 21. The method according to any one of aspects 1 to 20, wherein the eye box position has more than one eye position associated therewith.

[0198] Aspect 22. According to the method of any one of aspects 1 to 21, the light source includes a display.

[0199] Aspect 23. The method according to any one of aspects 1 to 22, wherein the light source comprises a perforated pattern backlit by a planar light source.

[0200] Aspect 24. The method according to any one of aspects 1 to 23, wherein the first virtual image is configured as a first virtual image at a first projection distance parallel to the head-up display system.

[0201] Aspect 25. The method according to any one of aspects 1 to 24, wherein the first distance is less than the first projected distance.

[0202] Aspect 26. The method according to any one of aspects 1 to 25, wherein the first projected distance is greater than xm, where x = 3, or 4, or 5, or 6, or 7, or 8, or 9, or 10, or 15, or 20, or 30, or 40, or 50, or 60, or 70, or 80, or 90, or 100.

[0203] Aspect 27. The method according to any one of aspects 1 to 26, wherein the first projected distance is less than ym, where y = 110, or 100, or 90, or 80, or 70, or 60, or 50, or 40, or 30.

[0204] Aspect 28. The method according to any one of aspects 1 to 27, wherein the first projection distance is between 5m and 15m.

[0205] Aspect 29. According to the method of any one of aspects 1 to 28, wherein the first distance is not greater than jm, where j = 5, or 4.5, or 4, or 3.5, or 3, or 2.5, or 2, or 1.5, or 1, or 0.5.

[0206] Aspect 30. The method according to any one of aspects 1 to 29, wherein the first distance is at least km, where k = 0.1, or 0.2, or 0.3, or 0.4, or 0.5, or 0.6, or 0.7, or 0.8, or 0.9, or 1, or 1.1, or 1.2, or 1.3, or 1.4, or 1.5, or 1.6, or 1.7, or 1.8, or 1.9, or 2.

[0207] Aspect 31. The method according to any one of aspects 1 to 30, wherein the first distance is between 0.5m and 5m, more preferably between 0.5m and 4m, and even more preferably between 0.5m and 3m.

[0208] Aspect 32. The method according to any one of aspects 1 to 24, wherein the first distance is greater than the first projected distance.

[0209] Aspect 33. According to the method of aspect 32, wherein the first distance is greater than x'm, where x' = 3, or 4, or 5, or 6, or 7, or 8, or 9, or 10, or 15, or 20, or 30, or 40, or 50, or 60, or 70, or 80, or 90, or 100.

[0210] Aspect 34. According to the method of aspect 32 or aspect 33, wherein the first distance is less than y'm, where y' = 110, or 100, or 90, or 80, or 70, or 60, or 50, or 40, or 30.

[0211] Aspect 35. The method according to any one of aspects 32 to 34, wherein the first distance is between 5m and 15m.

[0212] Aspect 36. The method according to any one of aspects 32 to 35, wherein the first projected distance is less than or equal to j'm, where j' = 5, or 4.5, or 4, or 3.5, or 3, or 2.5, or 2, or 1.5, or 1, or 0.5.

[0213] Aspect 37. The method according to any one of aspects 32 to 36, wherein the first projected distance is at least k'm, where k' = 0.1, or 0.2, or 0.3, or 0.4, or 0.5, or 0.6, or 0.7, or 0.8, or 0.9, or 1, or 1.1, or 1.2, or 1.3, or 1.4, or 1.5, or 1.6, or 1.7, or 1.8, or 1.9, or 2.

[0214] Aspect 38. The method according to any one of aspects 32 to 37, wherein the first projection distance is between 0.5m and 5m, more preferably between 0.5m and 4m, and even more preferably between 0.5m and 3m.

[0215] Aspect 39. The method according to any one of aspects 1 to 25 or aspect 32, wherein the first projection distance is greater than 20m.

[0216] Aspect 40. According to the method of aspect 39, wherein the first projection distance is greater than x'' m, where x'' = 30, or 40, or 50, or 60, or 70, or 80, or 90, or 100.

[0217] Aspect 41. According to the method of aspect 39 or aspect 40, wherein the first projected distance is less than y'' m, where y'' = 110, or 100, or 90, or 80, or 70, or 60, or 50, or 40, or 30.

[0218] Aspect 42. The method according to any one of aspects 1 to 41, wherein the first image of the first virtual image is captured when the imaging system is positioned at the eyebox location.

[0219] Aspect 43. The method according to any one of aspects 1 to 42, wherein the first image of the first virtual image is captured with the camera positioned at the eyebox location.

[0220] Aspect 44. The method according to any one of aspects 1 to 43, wherein the first image of the first virtual image is captured with the camera positioned at the first eye position in the eyebox.

[0221] Aspect 45. The method according to any one of aspects 1 to 44, wherein the first image of the first virtual image is captured at the first eye position in the eyebox.

[0222] Aspect 46. The method of aspect 45, wherein the method includes capturing a second image of a first virtual image at a second eye position in an eyebox at a first image plane, and using the second image of the first virtual image to determine a first performance factor.

[0223] Aspect 47. The method according to any one of aspects 1 to 46, wherein multiple images of the first virtual image are captured, each image being captured at a different eye position in the eyebox.

[0224] Aspect 48. According to the method of aspect 48 (should be 47), each of the plurality of images is used to determine a corresponding first performance parameter.

[0225] Aspect 49. The method according to aspect 47 or aspect 48, wherein each image is used to construct an image of the first virtual image, and the image of the constructed first virtual image is used to determine a first performance parameter.

[0226] Aspect 50. The method according to any one of aspects 1 to 49, wherein the window glass includes a first window glass material pane joined to a second window glass material pane by a sandwich structure comprising at least one piece of adhesive interlayer material, the second window glass material pane being an inner panel facing the interior of the vehicle when the window glass is installed in the vehicle, the inner panel having an inner surface facing the interior of the vehicle when the window glass is installed in the vehicle, wherein the first virtual image generated includes light reflected from at least the inner surface of the inner panel.

[0227] Aspect 51. The method according to aspect 50, wherein the first window glass material pane is an outer panel of the vehicle in which the window glass is mounted for facing the external environment, wherein the outer panel has an outer surface of the vehicle in which the window glass is mounted for facing the external environment.

[0228] Aspect 52. The method according to aspect 50 or aspect 51, wherein the first virtual image produced comprises light reflected from at least the sandwich structure.

[0229] Aspect 53. The method according to any one of aspects 50 to 52, wherein the first virtual image produced in these embodiments comprises light reflected from at least the outer surface.

[0230] Aspect 54. The method according to any one of aspects 1 to 53, wherein the imaging system includes a first camera located at a first eye position in the eye box to capture a first image of the first virtual image, and a second camera located at a second eye position in the eye box to capture a second image of the first virtual image.

[0231] Aspect 55. The method according to any one of aspects 1 to 53, wherein the imaging system is movable relative to a window to capture a first image when the imaging system is in a first position relative to the window and to capture a second image when the imaging system is in a second position relative to the window.

[0232] Aspect 56. According to the method of aspect 55, wherein the first image is captured at the first eye position in the eye box.

[0233] Aspect 57. According to the method of aspect 55 or aspect 57, wherein the imaging system is moved to a second position relative to the window glass.

[0234] Aspect 58. The method according to any one of aspects 55 to 57, wherein the second image is captured at a second position in the eye box.

[0235] Aspect 59. The method according to any one of aspects 55 to 58, wherein multiple images are captured to construct an image of the entire first virtual image.

[0236] Aspect 60. The method according to any one of aspects 1 to 59, wherein the light from the light source is in the form of a pattern, preferably comprising at least one point and / or at least one line.

[0237] Aspect 61. The method according to aspect 60, wherein the pattern is specifically designed for detecting window glass intended for use in a particular model of vehicle.

[0238] Aspect 62. The method according to any one of aspects 1 to 61, wherein the light from the light source is in the form of a pattern, and a first virtual image of the pattern at a first image plane is distorted by a window glass, wherein when determining the performance parameters of the window glass, the first virtual image distorted by the window glass is compared with a reference image of the pattern.

[0239] Aspect 63. The method according to aspect 62, wherein the reference image is an undistorted image, which is then distorted to be projected onto the window glass being detected.

[0240] Aspect 64. The method according to any one of aspects 1 to 63, wherein a first performance parameter of the first head-up display area of ​​the window glass is determined using only a first image of the first virtual image.

[0241] Aspect 65. According to the method of aspect 64, wherein the first image of the first virtual image is captured when the imaging system is positioned at a first eye position in the eye box.

[0242] Aspect 66. The method according to any one of aspects 1 to 65, wherein during (ii), light from the light source illuminates at least the entire first head-up display area.

[0243] Aspect 67. The method according to aspect 66, wherein at (iii), the entire first virtual image from a fully illuminated first head-up display area is imaged, and the captured first image is an image of the entire first virtual image.

[0244] Aspect 68. According to the method of aspect 66, wherein at (iii) only a portion of the entire virtual image from a fully illuminated first head-up display area is captured as a first image.

[0245] Aspect 69. According to the method of aspect 66, wherein the image of the entire virtual image from the first head-up display area is constructed from a plurality of images, each of the plurality of images having a different portion of the entire virtual image from the first head-up display area.

[0246] Aspect 70. The method according to any one of aspects 1 to 65, wherein the performance of the entire first head-up display area is determined by performing steps (ii) and (iii) multiple times to illuminate multiple different portions of the first head-up display area of ​​the window glass.

[0247] Aspect 71. According to the method of aspect 70, each portion of the first head-up display area is individually illuminated.

[0248] Aspect 72. The method according to aspect 70 or aspect 71, wherein each different part is used to determine the corresponding first performance parameter.

[0249] Aspect 73. The method according to any one of aspects 70 to 72, wherein each corresponding first image from a different illumination portion of a first head-up display area is used to construct an image of the entire virtual image from the first head-up display area.

[0250] Aspect 74. According to the method of aspect 73, wherein an image of the entire virtual image from the first head-up display area, thus constructed, is used to determine a first performance parameter of the first head-up display area of ​​the window glass.

[0251] Aspect 75. The method according to any one of aspects 1 to 74, wherein the window glass is configured for installation in a vehicle such that, in use, light from a head-up display projector illuminates a second head-up display area of ​​the window glass to generate a virtual image at a second projection distance from the eye box position, wherein the second projection distance is less than the first projection distance.

[0252] Aspect 76. The method according to aspect 75, wherein the method of detecting the window glass includes detecting a second head-up display area to determine at least a first performance parameter of the second head-up display area of ​​the window glass.

[0253] Aspect 77. The method of aspect 76, wherein the method of detecting the second head-up display area comprises: directing light from the light source or another light source to illuminate at least a portion of the second head-up display area of ​​the window glass, thereby generating a second virtual image at a second image plane located at a second distance from the eyebox position; imaging the second virtual image at the second image plane using an imaging system to capture a first image of the second virtual image; and using the first image of the second virtual image to determine at least a first performance parameter of the second head-up display area of ​​the window glass.

[0254] Aspect 78. According to the method of aspect 77, wherein a first performance parameter of the second head-up display area of ​​the window glass is compared with an appropriate performance specification.

[0255] Aspect 79. The method according to any one of aspects 75 to 78, wherein the second distance between the second image plane and the position of the eye box is the same as the first distance between the first image plane and the position of the eye box.

[0256] Aspect 80. The method according to any one of aspects 75 to 79, wherein the second distance is the same as the second projected distance.

[0257] Aspect 81. According to the method of any one of aspects 75 to 80, the first projection distance is between 5m and 20m, and the second projection distance is between 1m and 5m.

[0258] Aspect 82. The method according to any one of aspects 75 to 81, wherein a first head-up display area of ​​the window glass has a first area, and a second head-up display area of ​​the window glass has a second area, wherein the first area is larger than the second area.

[0259] Aspect 83. The method according to aspect 82, wherein the first area is at least 1.5 times the area of ​​the second area, preferably 2 times the area of ​​the second area, more preferably 3 times, 4 times, 5 times, 6 times, 7 times, 8 times, 9 times, or 10 times the area of ​​the second area.

[0260] Aspect 84. According to the method of aspect 82 or aspect 83, wherein the first area is less than 20 times the area of ​​the second area.

[0261] Aspect 85. The method according to any one of aspects 75 to 84, wherein the first region is used for an augmented reality head-up display system and the second region is used for a conventional head-up display system.

[0262] Aspect 87. The method of any one of claims 1 to 74, wherein the method is used to detect a window glass configured for installation in a vehicle, such that, in use, light from a head-up display projector illuminates a second head-up display area of ​​the window glass to generate a second virtual image at a second projection distance from the eye box position, wherein the second projection distance is greater than the first projection distance.

[0263] Aspect 88. The method according to aspect 87, wherein the method of detecting window glass includes detecting a second head-up display area to determine at least a first performance parameter of the second head-up display area of ​​the window glass.

[0264] Aspect 89. The method of aspect 88, wherein the method of detecting the second head-up display area comprises: directing light from the light source or another light source to illuminate at least a portion of the second head-up display area of ​​the window glass, thereby generating a second virtual image at a second image plane located at a second distance from the eye box position; imaging the second virtual image at the second image plane using an imaging system to capture a first image of the second virtual image; and using the first image of the second virtual image to determine at least a first performance parameter of the second head-up display area of ​​the window glass.

[0265] Aspect 90. According to the method of aspect 89, wherein a first performance parameter of the second head-up display area of ​​the window glass is compared with an appropriate performance specification.

[0266] Aspect 91. The method according to any one of claims 87 to 90, wherein the second distance between the second image plane and the position of the eye box is the same as the first distance between the first image plane and the position of the eye box.

[0267] Aspect 92. The method according to any one of aspects 87 to 91, wherein the first distance is the same as the second projected distance.

[0268] Aspect 93. The method according to any one of aspects 1 to 92, wherein the method includes a calibration step, such that during (iv), a first performance parameter measured at a first image plane can be transformed using at least a first correction factor determined during the calibration step to a corresponding first performance parameter at a first projection distance from the eyebox position or at another projection distance from the eyebox position.

[0269] Aspect 94. The method according to aspect 93, wherein the first correction factor is determined by measurement or ray tracing of a first performance parameter of a reference virtual image generated at a first image plane and a first projection distance or another distance.

[0270] Aspect 95. The method according to aspect 94 or aspect 95, wherein the first correction factor includes a factor for transforming at least one of ghosting, distortion, magnification, aspect ratio and displacement.

[0271] Aspect 96. The method according to any one of aspects 1 to 95, wherein a first performance parameter of the first head-up display area of ​​the window glass is related to ghosting, distortion, magnification, aspect ratio, or displacement.

[0272] Aspect 97. The method according to any one of aspects 1 to 96, wherein the first virtual image at a first distance is configured as a first virtual image at a first projection distance parallel to the head-up display system.

[0273] Aspect 98. The method according to any one of aspects 1 to 97, wherein the first virtual image at the first distance is configured parallel to the eyebox position.

[0274] Aspect 99. The method according to any one of aspects 1 to 98, wherein when a window is installed in a vehicle and light from a head-up display projector illuminates a first head-up display area of ​​the window to generate a first virtual image at a first projection distance from the eye box position, the first virtual image at the first projection distance from the eye box position is part of an inclined virtual image, wherein the inclined virtual image is inclined relative to the eye box position.

[0275] Aspect 100. The method according to any one of aspects 1 to 99, wherein when the window glass is installed in a vehicle, in use, light from the head-up display projector also illuminates a second head-up display area of ​​the window glass to generate a second virtual image at a second projection distance from the eye box position.

[0276] Aspect 101. The method according to any one of aspects 1 to 100, wherein the first virtual image at the first projection distance is part of an inclined virtual image, wherein the inclined virtual image is inclined relative to the eye box position.

[0277] Aspect 102. The method according to any one of aspects 1 to 101, wherein the first virtual image at the first projection distance is part of an inclined virtual image, which is set to be tilted forward relative to the vertical direction of the vehicle.

[0278] Aspect 103. An apparatus for detecting window glass configured for installation in a vehicle having a head-up display projector, such that, in use, light from the head-up display projector illuminates a first head-up display area of ​​the window glass to generate a first virtual image at a first projection distance from an eyepiece location; the apparatus includes: a clamp, a light source, an imaging system, and a computer; the clamp is arranged relative to the light source and configured to hold the windshield during a detection measurement such that light from the light source illuminates the window glass to generate a virtual image at a first image plane located at a first distance from the eyepiece location; the imaging system is arranged relative to the window glass during the detection step to capture an image of the virtual image at the first image plane through the window glass; and wherein the computer has a program for analyzing the captured image of the virtual image at the first image plane to determine at least a first performance parameter of the window glass, wherein the first image plane is located at a position different from the first projection distance.

[0279] Aspect 104. The apparatus according to aspect 103, wherein the imaging system is positioned at the eye box location.

[0280] Aspect 105. The apparatus according to aspect 103 or aspect 104, wherein the imaging system includes at least one fixed camera and / or at least one movable camera.

Claims

1. A method of inspecting a window pane for use in a head-up display system, the window pane being configured for mounting in a vehicle having a head-up display projector such that, in use, light from the head-up display projector illuminates a first head-up display region of the window pane to produce a first virtual image at a first projection distance from an eyebox location, the method of inspecting the window pane comprising: (i) positioning the window pane relative to a light source; (ii) directing light from the light source to illuminate at least a portion of the first head-up display region of the window pane to thereby produce a first virtual image at a first image plane, the first image plane being a first distance from the eyebox location; (iii) imaging the first virtual image at the first image plane using an imaging system to capture a first image of the virtual image at the first image plane; and (iv) using the first image of the first virtual image at the first image plane to determine at least a first performance parameter of the first head-up display region of the window pane; wherein the first distance is different to the first projection distance.

2. The method of claim 1, wherein the first performance parameter of the first head-up display region of the window pane is compared to an appropriate performance specification.

3. The method of claim 1 or claim 2, wherein the first distance is less than the first projection distance.

4. The method of any one of the preceding claims, wherein the first projection distance is greater than 3m, preferably greater than 5m, more preferably greater than 7m.

5. The method of any one of the preceding claims, wherein the first projection distance is less than 150m, more preferably less than 50m, even more preferably less than 20m, even more preferably less than 15m.

6. The method of any one of the preceding claims, wherein the first distance is less than 4m, preferably less than 3m, more preferably less than 2.5m.

7. The method of any one of the preceding claims, wherein the first distance is greater than 0.5m, preferably greater than 1m.

8. The method of any one of the preceding claims, wherein the first projection distance is between 7m and 15m, and wherein the first distance is between 1m and 3m.

9. The method of claim 1 or claim 2, wherein the first distance is greater than the first projection distance.

10. The method of claim 9, wherein the first distance is between 5m and 15m, and / or wherein the first projection distance is between 0.5m and 5m.

11. The method of any one of the preceding claims, wherein the first head-up display region is for an augmented reality head-up display system.

12. The method of any one of the preceding claims, wherein the first head-up display region is about at least 5% of the area of the window pane.

13. The method of any one of the preceding claims, wherein the first head-up display region is less than about 50% of the area of the window pane, more preferably less than about 25% of the area of the window pane.

14. The method of any one of the preceding claims, wherein, during (ii), the light directed from the light source illuminates at least the entire first head-up display region.

15. The method of claim 14, wherein at (iii) the entire virtual image from the first head-up display area is imaged to produce a first image.

16. The method of claim 14, wherein after (ii) the first virtual image is imaged to capture at least a second image, the second image having a different portion of the first virtual image than the first image, preferably wherein the first image at least partially overlaps the second image.

17. The method of claim 16, wherein for each of the first image and the second image a respective first performance parameter is determined.

18. The method of any one of the preceding claims, wherein the performance of the entire first head-up display area is determined by performing steps (ii) and (iii) a plurality of times to illuminate a plurality of different portions of the first head-up display area of the window pane.

19. The method of claim 18, wherein each portion of the first head-up display area is illuminated individually.

20. The method of claim 18 or claim 19, wherein each different portion is used to determine a respective first performance parameter.

21. The method of any one of claims 1 to 13, wherein steps (ii) and (iii) are repeated a plurality of times, such that the plurality of first images so produced are used to construct an image of the entire first virtual image from the first head-up display area.

22. The method of any one of the preceding claims, wherein the window pane is configured for mounting in a vehicle such that, in use, light from the head-up display projector illuminates a second head-up display area of the window pane to produce a second virtual image at a second projection distance from the eyebox location, wherein the second projection distance is different from the first projection distance.

23. The method of claim 22, comprising detecting the second head-up display area to determine at least a first performance parameter of the second head-up display area of the window pane.

24. The method of claim 23, wherein the method of detecting the second head-up display region comprises: directing light from the light source or another light source to illuminate at least a portion of the second head-up display area of the window pane to produce a second virtual image at a second image plane, the second image plane being located at a second distance from the eyebox location; imaging the second virtual image at the second image plane using an imaging system to capture a first image of the second virtual image; and determining at least a first performance parameter of the second head-up display area of the window pane using the first image of the second virtual image.

25. The method of claim 24, wherein the first performance parameter of the second head-up display area of the window pane is compared to an appropriate performance specification.

26. The method of claim 24 or claim 25, wherein the second distance of the second image plane from the eyebox location is the same as the first distance of the first image plane from the eyebox location.

27. The method of any one of claims 22 to 26, wherein the first distance is the same as the second projection distance.

28. The method of any one of claims 22 to 27, wherein the second projection distance is greater than the first projection distance.

29. The method of any one of claims 22 to 27, wherein the second projection distance is less than the first projection distance.

30. The method of any one of claims 22 to 27, wherein the first projection distance is between 5m to 20m and the second projection distance is between 1m to 5m.

31. The method of any one of the preceding claims, wherein the first performance parameter of the first head-up display area of the window pane is related to ghosting, distortion, magnification, aspect ratio, or displacement.

32. The method of any one of the preceding claims, wherein the first virtual image at the first projection distance is part of a tilted virtual image, wherein the tilted virtual image is tilted relative to the eyebox position.

33. The method of any one of the preceding claims, wherein the first virtual image at the first projection distance is part of a tilted virtual image, the tilted virtual image being arranged to be tilted forward relative to a vertical direction of the vehicle.

34. An apparatus for testing a window pane configured for installation in a vehicle having a head-up display projector such that, in use, light from the head-up display projector illuminates a first head-up display area of the window pane to produce a first virtual image at a first projection distance from an eyebox position; the apparatus comprising: a fixture, a light source, an imaging system, and a computer; the fixture is arranged relative to the light source and is configured to hold the windshield during a test measurement such that light from the light source illuminates the window pane to produce a virtual image at a first image plane, the first image plane is located at a first distance from the eyebox position; the imaging system is arranged relative to the window pane during the test step to capture an image of the virtual image at the first image plane through the window pane; and wherein the computer has a program for analyzing the captured image of the virtual image at the first image plane to determine at least a first performance parameter of the window pane, wherein the first image plane is located at a different position than the first projection distance.

35. The apparatus of claim 34, wherein the imaging system is positioned at the eyebox position.

Images