Glass laminate including reflective film

Abstract

To solve the problem in which a wedge design that provides a difference in slope between a reflective film and at least one of the outer surfaces of the glass laminate has difficulty in providing a desired slope difference in a cost-effective manufacturing process.SOLUTION: A glass laminate includes: first and second glass layers 104; a reflective film having opposed first and second major surfaces and disposed between the first and second glass layers; a first adhesive layer 117 disposed between and bonding together the first glass layer 102 and the reflective film; and a second adhesive layer 119 disposed between and bonding together the second glass layer 104 and the reflective film. The second adhesive layer is thicker than the first adhesive layer. The first major surface of the reflective film is separated from an outermost major surface of the first glass layer by a distance d1. The second major surface of the reflective film is separated from an outermost major surface of the second glass layer by a distance d2. 0.05≤d1 / d2≤0.9.SELECTED DRAWING: Figure 1A

Description

[Background technology]

[0001] A head-up display may include a projector for projecting an image onto a windshield, which in some cases is a glass laminate, which reflects the projected image to a viewer. Summary of the Invention

[0002] In some embodiments of the present disclosure, a glass laminate is provided, the glass laminate including: first and second glass plies having substantially parallel outermost major surfaces facing away from each other; a reflective film having opposing first and second major surfaces and disposed between the first and second glass plies, the first and second major surfaces facing the respective first and second glass plies; a first adhesive layer disposed between the first glass ply and the reflective film bonding them together; and a second adhesive layer disposed between the second glass ply and the reflective film bonding them together. The reflective film has an average reflectivity of at least 15% for a first polarization state within a predetermined visible wavelength range at a predetermined angle of incidence and an average transmittance of at least 30% for an orthogonal second polarization state within the predetermined visible wavelength range at a predetermined angle of incidence. The second adhesive layer is thicker than the first adhesive layer, such that the first major surface of the reflective film is separated from the outermost major surface of the first glass layer by a distance d1 and the second major surface of the reflective film is separated from the outermost major surface of the second glass layer by a distance d2, where 0.05≦d1 / d2≦0.9.

[0003] In some embodiments, a glass laminate is provided that includes first and second glass layers having substantially parallel outermost major surfaces and a reflective film, the reflective film including a plurality of alternating polymer interference layers, asymmetrically disposed between the outermost major surfaces. A light source positioned within 2 meters of the glass laminate projects a line onto the outermost major surface of the first glass layer along a first direction that forms an angle θ with respect to a normal to the glass laminate within a range of 30 to 85 degrees, such that a first portion of the projected line is reflected from the reflective film and a second portion of the projected line is reflected from the outermost major surface of the first glass layer when the line extends along a second direction orthogonal to a first plane defined by the first direction and the normal and has a projected intensity distribution about a center line of the projected line that has a full width at half maximum of 0.05 degrees or less. The reflected image of the line includes a primary reflected image portion defined by the reflected first portion and a first ghost portion defined by the reflected second portion. The first ghost portion substantially overlaps the primary reflected image portion.

[0004] In some embodiments of the present disclosure, a glass laminate is provided, comprising first and second glass layers having substantially parallel outermost major surfaces, and a reflective film, the reflective film including a plurality of alternating polymer interference layers and disposed between and adhered to the first and second glass layers through respective first and second adhesive layers. The first adhesive layer has a thickness no greater than 0.6 times the thickness of the second adhesive layer. A light source projects a plurality of parallel lines onto the outermost major surface of the first glass layer along a first direction that forms an angle θ between 30 and 85 degrees with respect to a normal to the glass laminate, and the parallel lines extend along a second direction orthogonal to a first plane defined by the first direction and the normal, and are spaced apart along a third direction orthogonal to the first direction within the first plane, such that a first portion of each projected line is reflected from the reflective film. The reflected image of each line includes the reflected first portion. Each reflected image has a luminance distribution that defines a centerline of the reflected image. The distribution of the angle α between the center line of the reflected image and the second direction has a full width at half maximum of less than 3 degrees. [Brief explanation of the drawings]

[0005] [Figure 1A] 1 is a schematic cross-sectional view of a glass laminate and a light source. [Figure 1B] 1 is a schematic cross-sectional view of a glass laminate and a light source. [Figure 2] FIG. 1 is a schematic cross-sectional view of an optical film. [Figure 3A] FIG. 2 is a schematic diagram of a projected line. [Figure 3B] FIG. 2 is a schematic diagram of a reflection line. [Figure 3C] 3C is a schematic diagram of the distribution of angles between the center line of the reflection line of FIG. 3B and a specified direction. [Figure 4] FIG. 4 is a schematic diagram of a reflection luminance distribution 460 of a reflection image. [Figure 5A] FIG. 1 is a schematic diagram of an illuminance distribution. [Figure 5B] FIG. 1 is a schematic diagram of an illuminance distribution. [Figure 5C] FIG. 1 is a schematic diagram of an illuminance distribution. [Figure 6A] 10 is a schematic diagram of the luminance distribution of the primary reflected image portion and the first and second ghost portions. FIG. [Figure 6B] 6B is a schematic diagram of the reflected luminance distribution including contributions from the primary reflected image portion and the first and second ghost portions of FIG. 6A; [Figure 7] FIG. 1 is a schematic cross-sectional view of a glass laminate having opposing major surfaces that define an angle δ therebetween. [Figure 8] FIG. 2 is a schematic front view of the windshield. [Figure 9] The brightness distribution across the reflected image of the projected line. [Figure 10] The brightness distribution across the reflected image of the projected line. [Figure 11] The brightness distribution across the reflected image of the projected line. [Figure 12] The brightness distribution across the reflected image of the projected line. [Figure 13A] A reflection of multiple projected lines. [Figure 13B] A reflection of multiple projected lines. [Figure 13C] A reflection of multiple projected lines. [Figure 14] 1 is a plot of the distribution of the center lines of the reflection lines. DETAILED DESCRIPTION OF THE INVENTION

[0006] In the following description, reference is made to the accompanying drawings, which form a part hereof, and in which are shown by way of illustration various embodiments. The drawings are not necessarily to scale. It is to be understood that other embodiments are contemplated and may be made without departing from the scope or spirit of the specification. Accordingly, the following detailed description is not to be taken in a limiting sense.

[0007] A head-up display typically includes a display or projector that projects an image onto a windshield or combiner that reflects the projected image to a viewer. In some cases, the windshield is a glass laminate that includes a reflective film between two glass layers to reflect the projected image. Ghost images reflected from the outer surface of the glass laminate can degrade the image quality of the reflected image. In some cases, the glass laminate has a wedge-shaped design that creates a gradient difference between the reflective film and at least one of the outer surfaces of the glass laminate. The gradient difference can be selected to shift the ghost image onto the image reflected by the film so that the ghost does not significantly degrade the clarity of the reflected image. However, such wedge-shaped designs are often not preferred in many embodiments, at least in part due to the difficulty of creating the desired gradient difference in a cost-effective manufacturing process.

[0008] According to some embodiments of the present disclosure, it has been found that utilizing a reflective film asymmetrically disposed between glass layers having substantially parallel outermost major surfaces can improve perceived image quality by shifting ghost images reflected from the front major surface so that they are closer to the primary reflected image. In some embodiments, at least one ghost image substantially overlaps the image reflected from the reflective film. Traditionally, a relatively thick layer (e.g., 0.76 mm) of polyvinyl butyral (PVB) is used to laminate the glass layers together in a windshield. In some embodiments, a thin (e.g., 50 microns or less) adhesive layer is used to laminate the reflective film to the glass layer facing the projector, and a thicker (e.g., 700 microns or more) adhesive layer is used to laminate the reflective film to the glass layer on the opposite side. This has been found to shift the ghost images sufficiently so that they are closer to or substantially overlap the primary reflected image and therefore do not significantly degrade the clarity of the reflected image.

[0009] The thinner adhesive layer can be, for example, a traditional acrylate-based optically clear adhesive (OCA) instead of the PVB layer commonly used in windshield glass laminates. Windshield glass laminates are sometimes included for their improved impact resistance compared to using a single glass layer. For example, one layer can hold glass shards in place when an object strikes the other layer and cracks it. Using a layer of OCA as a thin adhesive layer and a layer of PVB as a thick adhesive layer has been found to provide impact resistance comparable to traditional windshield glass laminates. Specifically, in some embodiments, when a 5-pound steel ball is dropped from 10 feet onto the glass layer adjacent to the thicker adhesive layer on the glass laminate, the ball is stopped by the laminate and the glass shards do not separate from the glass laminate.

[0010] Another advantage of the glass laminate according to some embodiments of the present description is improved fidelity of the reflected image. Utilizing a reflective film between the glass layers and using a traditional windshield adhesive layer can result in a decrease in the flatness of the reflective film, which can cause waviness when, for example, a line is projected onto the glass laminate. It has been found that using a thinner adhesive layer on the side of the reflective film facing the projector reduces this waviness.

[0011] 1A is a schematic cross-sectional view of a glass laminate 100 and a light source 122. The glass laminate 100 includes first and second glass layers 102 and 104 having substantially parallel outermost major surfaces 103 and 105 facing away from each other, and a reflective film 110 having opposing first and second major surfaces 112 and 114 disposed between the first and second glass layers 102 and 104, with the first and second major surfaces 112 and 114 facing the respective first and second glass layers 102 and 104. In some embodiments, the reflective film 110 has an average reflectivity of at least 15% (e.g., in a range of 15% to 30%, or about 20%) for a first polarization state (e.g., polarization state 131 shown in FIG. 1B, which in the illustrated embodiment is a p-polarization state) within a predetermined visible wavelength range at a predetermined angle of incidence, and an average transmittance of at least 30% for an orthogonal second polarization state (e.g., polarization state 132 shown in FIG. 1B, which in the illustrated embodiment is an s-polarization state) within the predetermined visible wavelength range at a predetermined angle of incidence. In some embodiments, the reflective film 110 comprises a plurality of alternating polymer interference layers as further described elsewhere herein. The glass laminate 100 includes a first adhesive layer 117 disposed between and bonding together the first glass layer 102 and the reflective film 110, and a second adhesive layer 119 disposed between and bonding together the second glass layer 104 and the reflective film 110. The second adhesive layer 119 may optionally include an optically absorbing material 144 as further described elsewhere herein.

[0012] In some embodiments, second adhesive layer 119 is thicker than first adhesive layer 117 such that first major surface 112 of reflective film 110 is separated from outermost major surface 103 of first glass layer 102 by a distance d1 and second major surface 114 of reflective film 110 is separated from outermost major surface 105 of second glass layer 104 by a distance d2, where 0.05≦d1 / d2≦0.9. In some embodiments, 0.05≦d1 / d2≦0.8, or 0.1≦d1 / d2≦0.8, or 0.2≦d1 / d2≦0.7. In some embodiments, second adhesive layer 119 is at least 2, 3, 5, 10, 20, 50, 100, or 200 times thicker than first adhesive layer 117. In some embodiments, first adhesive layer 117 has a thickness in the range of 1 micron to 100 microns, and second adhesive layer 119 has a thickness in the range of 100 microns to 1000 microns. In some embodiments, first adhesive layer 117 has a thickness in the range of 1 micron to 50 microns, and second adhesive layer 119 has a thickness in the range of 700 microns to 1000 microns.

[0013] In some embodiments, the first and second glass layers 102 and 104 have substantially the same thickness. In this context, substantially the same thickness means within 5% of each other. In some embodiments, the first glass layer 102 has a thickness within a range of 0.95 to 1.05, or 0.97 to 1.03, or 0.98 to 1.02 times the thickness of the second glass layer 104. In some embodiments, the second glass layer 104 is thicker than the first glass layer 102. In some embodiments, the second glass layer 104 is at least 1.2 times, or 1.5 times, or 1.8 times, or 2 times thicker than the first glass layer 102. In some embodiments, the second glass layer 104 is no more than 4 times, or 3 times, or 2.5 times thicker than the first glass layer 102. Using a thinner first glass layer 102 positions the first ghost image closer to the primary reflected image, while using a thicker first glass layer 102 (e.g., having a thickness similar to that of the second glass layer 104) improves impact resistance. In some embodiments, the first glass layer 102 has a thickness less than 2.2 mm, or less than 2 mm, or less than 1.5 mm, or less than 1.2 mm. In some embodiments, the first glass layer 102 has a thickness greater than 0.6 mm, or greater than 0.8 mm.

[0014] In some embodiments, the light source 122 emits or projects an image of a line having a projected luminance distribution around a central line of the projected line having a full width at half maximum (FWHM) σ. The luminance distribution can be expressed as a function of x-coordinate as shown in FIG. 1A or in terms of angle from the direction of peak luminance or from the central ray 127 as shown schematically in FIG. 1B. Non-central rays 129a and 129b are also shown in FIG. 1B. Ray 129b makes an angle φ with the central ray 127. The luminance distribution can be expressed in terms of angle φ, where positive φ in FIG. 1B corresponds to positive x-coordinate in FIG. 1A. The luminance distribution can be determined using a detector with an input aperture in a plane perpendicular to the central ray reflected from the reflective film 110 (e.g., the xy plane, with reference to the xyz coordinate system of FIG. 1A). A suitable detector includes a PROMETRIC I8 imaging colorimeter available from Radiant Vision Systems (Redmond, WA). Luminosity, which may also be referred to as brightness, can be defined as the integral over wavelength of radiance times the photopic luminosity function defined by the Commission Internationale de l'Eclairage (CIE) in the CIE 1931 color space. Any relationship described herein with respect to luminance or luminance distribution can also apply to radiance or radiance distribution, or to intensity or intensity distribution.

[0015] In some embodiments, the light source 122 projects polarized light having a first polarization state 131. In FIG. 1B , ambient light rays 133 having a second polarization state 132 are shown transmitted through the reflective film 110, which may be a reflective polarizer. The light source 122 may be or include a display, such as a liquid crystal display (LCD) or an organic light emitting diode (OLED) display. In some embodiments, various optical components (e.g., curved mirror(s) and / or optical lens(es)) are included within the light source 122 to provide a desired light output to the glass laminate 100.

[0016] 2 is a schematic cross-sectional view of a reflective film 210, which may correspond to the reflective film 110. The reflective film 210 includes a plurality of alternating polymeric interference layers 241 and 242. In the illustrated embodiment, the plurality of alternating polymeric interference layers 241 and 242 are disposed on an optional skin layer 240. In some embodiments, a second skin layer is disposed adjacent to the plurality of alternating polymeric interference layers 241 and 242 on the opposite side of the skin layer 240. The skin layer 240 may optionally include an optically absorbing material 244. The optically absorbing material 244 may be a dye, a pigment, or a combination thereof, which may be dispersed in the polymeric material of the skin layer 240. In some embodiments, at least one of the inference layers 241 or 242 is oriented along a first direction (e.g., the x1 direction), and the optically absorbing material 244 is or includes a dichroic dye at least partially oriented along the first direction. Any of these optically absorbing materials may optionally be included in second adhesive layer 119 instead of, or in addition to, being included in skin layer 240. Optically absorbing materials may be included to reduce the brightness of ghost images reflected from outermost major surface 105, as further described elsewhere herein.

[0017] Interference layers reflect and transmit light primarily through optical interference. Reflecting and transmitting light primarily through optical interference means that the reflectance and transmittance of an interference layer can be reasonably explained by optical interference or can be reasonably accurately modeled as the result of optical interference. Adjacent pairs of interference layers with different refractive indices reflect light through optical interference when the pair has a total optical thickness (physical thickness multiplied by refractive index) of half the wavelength of the light. Interference layers typically have a physical thickness of less than 250 nm or less than 200 nm. Skin layers are typically non-interference layers that have an optical thickness too large to reflect and transmit light primarily through optical interference, typically having a physical thickness greater than 1 micron or 2 microns. The reflective film 210 can include more interference layers than are shown schematically in FIG. 2. For example, the reflective film 210 can include 50 to 800 interference layers.

[0018] Suitable materials for the alternating interference layers 241 and 242 and for the skin layer 240 include polyethylene naphthalate (PEN), copolymers containing PEN and polyester (e.g., polyethylene terephthalate (PET) or dibenzoate), glycol-modified polyethylene terephthalate (PETg), polycarbonate (PC), poly(methyl methacrylate) (PMMA), or blends of these classes of materials.

[0019] Exemplary reflective films formed from polymeric materials can be produced using coextrusion, casting, and orientation processes. Methods for producing such films are described in U.S. Patent No. 5,882,774 (Jonza et al.) "Optical Film," U.S. Patent No. 6,179,948 (Merrill et al.) "Optical Film and Process for Manufacture Thereof," U.S. Patent No. 6,783,349 (Neavin et al.) "Apparatus for Making Multilayer Optical Films," and U.S. Patent Application Publication No. 2011 / 0272849 (Neavin et al.) "Feedblock for Manufacturing Multilayer Polymeric Films." Reflective films useful for use in head-up displays are described in U.S. Patent Application Publication No. 2004 / 0135742 (Weber et al.).

[0020] The reflective film can be, for example, a partial mirror or a partially reflective polarizer. In some embodiments, with reference to the x1-x2-x3 coordinate system shown in Figure 2, the reflective film is oriented primarily along the x1 direction and has a stronger reflectivity for a first polarization state with an electric field along the x1 direction and a lower reflectivity for a second polarization state with an electric field along the x2 direction.

[0021] In some embodiments, the reflective film 110 or 210 has an average reflectivity of at least 15% for a first polarization state within a predetermined visible wavelength range at a predetermined angle of incidence and an average transmittance of at least 30% for an orthogonal second polarization state within the predetermined visible wavelength range at a predetermined angle of incidence. The predetermined visible wavelength range can be the entire visible wavelength range (about 400 nm to about 700 nm) or a portion of the visible wavelength range. In some embodiments, the predetermined visible wavelength range spans at least 450 nm to 650 nm. In some embodiments, the predetermined visible wavelength range spans 400 nm to 700 nm. In some embodiments, the reflective film 110 or 210 is reflective within narrow bands, for example, corresponding to wavelengths transmitted by red, green, and blue subpixels of a display. In this case, the predetermined wavelength range can be a disjoint red, green, and blue range. This can allow the reflective film to be transparent to both polarization states for wavelengths between the red and green ranges and between the green and blue ranges, thus increasing the transparency of the reflective film to ambient light.

[0022] The predetermined angle of incidence can be the angle θ (see FIG. 1A ) at which light source 122 is intended to project onto the glass laminate. The predetermined angle of incidence and / or angle θ can be in the range of 30 degrees to 85 degrees, or in the range of 50 degrees to 75 degrees, or in the range of 55 degrees to 70 degrees, or in the range of 55 degrees to 68 degrees, or in the range of 59 degrees to 68 degrees, or in the range of 55 degrees to 65 degrees, or in the range of 62 degrees to 65 degrees, or the predetermined angle can be, for example, about 55 degrees (e.g., 50 to 60 degrees, or 51 to 59 degrees), about 62 degrees (e.g., 58 to 66 degrees, or 59 to 65 degrees), or about 65 degrees (e.g., 61 to 69 degrees, or 62 to 68 degrees).

[0023] In some embodiments, the average reflectivity of the reflective film 110 or 210 for a first polarization state within a predetermined visible wavelength range at a predetermined angle of incidence is at least 20%, or at least 50%, or at least 70%. In some embodiments, the average transmittance for the reflective film 110 or 210 for a second polarization state within a predetermined visible wavelength range at a predetermined angle of incidence is at least 50%, or at least 70%.

[0024] Average reflectance and average transmittance within a given wavelength range refer to reflectance and transmittance averaged (unweighted) over the wavelengths within the given wavelength range. Reflectance and transmittance are determined for light incident on the reflective film in air, unless otherwise indicated.

[0025] In some embodiments, the reflective film includes absorbing material on one side of the film (e.g., in a skin layer) and not on the other, or includes more absorbing material on one side than the other. In this case, reflectance and transmittance are determined for light incident on the reflective film on the side of the film opposite the absorbing material, or opposite the more absorbing side. In some embodiments, the reflective film 210 is disposed between the first and second glass layers 102 and 104, with the skin layer 240 facing the second glass layer 104 and the absorbing material included within the skin layer 240. As further described elsewhere herein, this may be done to reduce the brightness of ghost images reflected from the outermost major surface 105 of the second glass layer 104.

[0026] When a reflective film is included in a glass laminate using a PVB layer having a thickness traditionally used in windshield glass laminates, distortion of the image reflected from the reflective film may occur due to a decrease in the flatness of the film. According to the present description, this distortion can be significantly reduced when a thin adhesive layer, such as a thin layer of an optically clear adhesive (e.g., an optically clear adhesive (e.g., an acrylate-based one) commonly used in optical components) is used in place of a PVB layer having a thickness traditionally used in windshield laminates.

[0027] Figure 3A is a schematic diagram of a plurality of parallel lines 350 that may be projected onto glass laminate 100 by light source 122. Figure 3B is a schematic diagram of a reflected image 352 of the plurality of parallel lines 350. Figure 3C is a schematic diagram of a distribution 356 of the angle α between a center line 354 of reflected image 352 and the y direction (see Figure 1A). Distribution 356 has a full width at half maximum 358 that may, for example, be less than 3 degrees.

[0028] Light source 122 projects light 120 onto glass laminate 100. Portions 124, 126, and 128 of the light reflect from glass laminate 100. Projected light 120 can be, for example, a projected line or multiple projected lines. Portions 124, 126, and 128 can refer to portions of a projected line or multiple projected line portions, as will be clear from the context. In some embodiments, the projected line(s) are in a first polarization state (e.g., a p-polarization state). In other embodiments, the projected line(s) are unpolarized.

[0029] The term "parallel lines" should be understood to refer to straight lines that are parallel to one another, unless otherwise indicated. The term "projected lines" should be understood to refer to projected straight lines, unless otherwise indicated. However, the term "centerline" is used to refer to a curve or line that may or may not be straight (e.g., a centerline may be curved and / or irregular).

[0030] In some embodiments, the glass laminate 100 includes first and second glass layers 102 and 104 having substantially parallel outermost major surfaces 103 and 105, and a plurality of alternating polymer interference layers 241 and 242, and a reflective film 110 or 210 disposed between and adhered to the first and second glass layers 102 and 104 through respective first and second adhesive layers 117 and 119, wherein the first adhesive layer 117 has a thickness that is 0.6 times or less (or 0.5 times or less, or 0.4 times or less, or 0.2 times or less, or 0.1 times or less) the thickness of the second adhesive layer 119, such that the light source 122 is irradiated by the first glass layer along a first direction (z′ direction) that forms an angle θ with respect to a normal 134 of the glass laminate 100 in a range of 30 degrees to 85 degrees. When a plurality of parallel lines 350 are projected onto the outermost major surface 103 of the glass layer 102 (and through the first glass layer onto the reflective film) so that the plurality of parallel lines 350 extend along a second direction (y-direction) orthogonal to a first plane (x'-z' plane) defined by the first direction and the normal 134, and are spaced apart along a third direction (x'-direction) within the first plane and orthogonal to the first direction, a first portion 124 of each projected line is reflected from the reflective film 110 or 210, and a reflected image 352 of each line includes the reflected first portion 124, and each reflected image 352 has an intensity distribution that defines a center line 354 of the reflected image 352, and a distribution 356 of an angle α between the center line 354 of the reflected image 352 and the second direction (y-direction) has a full width at half maximum 358 that is less than 3 degrees. The distribution 356 can be obtained by determining the angle α between the center line 354 and the second direction at multiple locations along each line and determining the overall distribution of α. The multiple locations can be selected at uniform intervals along the second direction, and the number of locations can be increased until a statistical measure of the distribution, such as the full width at half maximum 358, converges.Related image analysis procedures that can be used to determine the distribution of centerline tangent angle α orientations are described in "Experimental investigation of collagen waviness and orientation in the arterial adventitia using confocal laser scanning microscopy," Rezakhaniha et al., Biomech Model Mechanobiol, 2012 Mar;11(3-4);461-73;doi:10.1007 / s10237-011-0325-z. In some embodiments, the full width at half maximum 358 of the distribution 356 of angles α is less than 2 degrees, or less than 1.5 degrees, or less than 1.2 degrees, or less than 1.1 degrees.

[0031] In some embodiments, the light source 122 is positioned within 2 m, 1.5 m, 1.2 m, or 1 m of the glass laminate 100. The distance between the light source 122 and the glass laminate 100 is the distance along the central light ray from the light source 122 to the glass laminate 100 (e.g., the distance between the light source 122 and the glass laminate 100 along the light ray 120).

[0032] 4 is a schematic diagram of a reflected intensity distribution 460 of a reflected image. The distribution can be expressed in terms of the lateral dimension (x-dimension) at the detector location or in terms of the angle from the direction of peak intensity (see, for example, the angle φ shown in FIG. 1B). The distribution can be determined over the length of a line, so a non-zero angle α with respect to the y-direction (see FIG. 3B) can increase the width of the distribution.

[0033] In some embodiments, the glass laminate 100 includes first and second glass layers 102 and 104 having substantially parallel outermost major surfaces 103 and 105, and a reflective film 110 or 210 including a plurality of alternating polymer interference layers 241 and 242, asymmetrically disposed between the outermost major surfaces 103 and 105, such that a light source 122 positioned within 2 m of the glass laminate 100 projects a line 350 a onto the outermost major surface 103 of the first glass layer 102 (and through the first glass layer onto the reflective film) along a first direction (z′ direction) that makes an angle θ with respect to a normal 134 of the glass laminate 100 in the range of 30 degrees to 85 degrees, such that the line When a projected image of a line 350a extends along a second direction (y direction) orthogonal to a first plane (x'-z' plane) defined by the direction perpendicular to the reflecting film 130 and normal 134, and has a projected intensity distribution around the center line of the projected line having a full width at half maximum σ of 0.05 degrees or less, a first portion 124 of the projected line 350a reflects from the reflective film, a second portion 126 of the projected line 350a reflects from the outermost major surface 103 of the first glass layer 102, and a reflected image 352a of the line includes a primary reflected image portion 472 (the portion below the dotted line in FIG. 4 ) defined by the reflected first portion 124, and a first ghost portion 474 (the portion between the dotted line and the solid line in FIG. 4 ) defined by the reflected second portion 126. The first ghost portion 474 substantially overlaps the primary reflected image portion 472.

[0034] In some embodiments, third portion 128 of projected line 350 reflects from the outermost major surface 105 of second glass layer 104, and reflected image 352 of the line further includes second ghost portion 476 (the portion between the dotted line and the solid line in FIG. 4 ) defined by reflected third portion 138, where second ghost portion 476 substantially overlaps primary reflected image portion 472.

[0035] In some embodiments, the reflected image 352a has a reflected luminance distribution 460 that has a maximum at a peak 462 of the reflected luminance distribution 460 and that decreases monotonically in at least one lateral direction (the +x direction) from the peak 462 to an edge 464 of the reflected image 352a. The edge 464 can be chosen to be where the luminance drops to 5% of the maximum luminance.

[0036] In some embodiments, reflected image 352a has a reflected luminance distribution 460, and the contribution to reflected luminance distribution 460 from first ghost portion 474 is not separately resolvable from the contribution to reflected luminance distribution 460 from primary reflected image portion 472 in a plot of reflected luminance distribution 460. When there are no features of distribution 460 that can be attributed to first ghost portion 474 without reference to primary reflected image portion 472, the contribution from first ghost portion 474 is not separately resolvable from the contribution from primary reflected image portion 472. For example, there is no local maximum or inflection point that can be attributed to first ghost portion 474. Once primary reflected portion 472 is determined, first ghost portion 474 can be determined. Primary reflected portion 472 can be determined from a known luminance distribution of a projected line, which allows the reflected luminance distribution to be determined when no ghosts are present. In the illustrated embodiment, the second ghost portion 476 is separately resolvable from the contribution of the primary reflected image portion 472 due to the presence of a maximum and an inflection point on the left-hand side of the distribution 460 .

[0037] In some embodiments, the full width at half maximum of the projected line is 0.03 degrees or less, or 0.02 degrees or less, hi some embodiments, the reflected image has an angular intensity distribution with a full width at half maximum of 0.1 degrees or less, or 0.07 degrees or less, or 0.05 degrees or less.

[0038] A portion of the reflected image substantially overlaps another portion of the reflected image if the intensity of the portion with the greater maximum intensity is at least as great as the intensity of the other portion at the quadrant (angular or linear) location of the other portion. This is shown schematically in Figures 5A-5C. In Figure 5A, the intensity of primary reflected image portion 572 is substantially less than the quadrant intensity 577 of first ghost portion 574 at quadrant location 579a. The full-width-at-quarter-maximum 578 of first ghost portion 574 is indicated. Location 579a is the quadrant location closest to primary reflected image portion 572. In Figure 5B, the intensity of primary reflected image portion 572 is equal to the quadrant intensity 577 of first ghost portion 574 at quadrant location 579b. In FIG. 5C , the brightness of primary reflected image portion 572 is greater than the brightness at quarter-maximum 577 of first ghost portion 574 at quarter-maximum position 579c. In the case shown in FIG. 5C , the brightness of primary reflected image portion 572 is greater than the brightness at half-maximum of first ghost portion 574 at half-maximum position. In FIG. 5C , the full-width at half-maximum 588 of first ghost portion 574 is indicated. First ghost portion 574 substantially overlaps with primary reflected image portion 572 in the cases shown in FIGS. 5B and 5C , but does not substantially overlap in the case shown in FIG. 5A . The overlap of a second ghost portion with a primary reflected image portion is similarly defined. In some embodiments where a portion of the reflected image is described as substantially overlapping another portion of the reflected image, the brightness of the portion with the greater maximum brightness is at least as great as the brightness of the other portion at the half-maximum (angular or linear) position of the other portion.

[0039] Figure 6A schematically shows the luminance distribution of primary reflected image portion 672, which substantially overlaps with first and second ghost portions 674 and 676. Figure 6B schematically shows reflected luminance distribution 660, which includes contributions from primary reflected image portion 672 and first and second ghost portions 674 and 676. The dotted lines indicate the locations of peaks in primary reflected image portion 672 and first and second ghost portions 674 and 676. The vertical direction (along the dotted lines) represents luminance in arbitrary units, and the horizontal direction represents angle or linear displacement.

[0040] In some embodiments, the glass laminate 100 includes an optically absorbing material disposed between the first glass layer 102 and the outermost major surface 105 of the second glass layer 104. In some embodiments, the optically absorbing material is disposed between the reflective film 110 and the outermost major surface 105 of the second glass layer 104, or between the alternating polymer interference layers of the reflective film 110 and the outermost major surface 105 of the second glass layer 104. In some embodiments, the second glass layer 104 is optically absorbing (e.g., has an optical absorption band in the near infrared extending into the red portion of the visible spectrum). As further described elsewhere herein, the optically absorbing material can be included, for example, in the skin layer 240 or in the adhesive layer 119. The optically absorbing material can be included to reduce the brightness of the second ghost compared to the first ghost. In some embodiments, the second ghost portion 476 has a brightness less than that of the first ghost portion 474. In some embodiments, the second ghost portion 476 has a brightness that is less than 0.6, 0.5, 0.4, 0.3, 0.2, 0.1, 0.05, or 0.01 times the brightness of the first ghost portion 474. The brightness of the first and second ghost portions is the peak value of the luminance distribution of the first and second ghost portions.

[0041] In some embodiments, the optically absorbing material has an absorbance as a function of polarization. For example, in some embodiments, the reflective film has an average reflectance of at least 15% (or at least 20%, or at least 50%, or at least 70%) for a first polarization state within a predetermined visible wavelength range at a predetermined angle of incidence and an average transmittance of at least 30% (or at least 50%, or at least 70%) for an orthogonal second polarization state within a predetermined visible wavelength range at a predetermined angle of incidence, and the optically absorbing material is optically absorbing for light having the first polarization state and substantially optically transmissive for light having the second polarization state (e.g., the absorbance for the second polarization state can be less than 0.2 times, or less than 0.1 times, the absorbance for the first polarization state).

[0042] As used herein, "substantially parallel" outermost major surfaces are sufficiently close to parallel that any deviation from parallelism results in a shift in the relative positions of the peaks of the first and second ghost portions of less than 10 percent. Substantially parallel outermost major surfaces can be parallel or nominally parallel. FIG. 7 is a schematic diagram of a glass laminate 700 having outermost major surfaces 703 and 705 defining an angle δ therebetween. In some embodiments, the substantially parallel outermost major surfaces define an angle δ therebetween of less than 0.05, 0.03, 0.02, 0.015, 0.012, 0.11, 0.01, 0.009, 0.007, 0.005, 0.003, or 0.001 degrees. The angle δ is the angle between the opposing outermost major surfaces, tangent to the plane at that location on the glass laminate. In some embodiments, δ is within any of the above ranges at every location on the glass laminate, or at every location over at least 80% or 90% of the area of ​​the glass laminate. In some embodiments, reflective film 110 is substantially parallel to outermost major surface 103 in the sense that any deviation from parallelism causes less than a 10 percent shift in the relative positions of the peaks of the first ghost and primary reflected image portions. Similarly, in some embodiments, reflective film 110 is substantially parallel to outermost major surface 105 in the sense that any deviation from parallelism causes less than a 10 percent shift in the relative positions of the peaks of the second ghost and primary reflected image portions.

[0043] 8 is a schematic front view of a windshield 800 that may be or include, for example, glass laminate 100. In some embodiments, the reflective film covers substantially the entire windshield 800 (e.g., at least 80% or at least 90% of the surface area of ​​the windshield). In some embodiments, the reflective film and the first and second glass layers are substantially coextensive with one another (e.g., either of the first and second glass layers and the reflective film may cover at least 80% or at least 90% of the surface area of ​​any other of the first and second glass layers and the reflective film).

[0044] This application is related to U.S. Provisional Patent Application No. 62 / 735,567, filed September 24, 2018, which is incorporated by reference herein in its entirety.

[0045] The following is a list of exemplary embodiments of the present specification.

[0046] The first embodiment is a glass laminate, first and second glass layers having substantially parallel outermost major surfaces facing away from each other; a reflective film having opposing first and second major surfaces and disposed between the first and second glass layers, the first and second major surfaces facing the respective first and second glass layers, the reflective film having an average reflectance for a first polarization state within a predetermined visible wavelength range at a predetermined angle of incidence of at least 15%, and an average transmittance for an orthogonal second polarization state within the predetermined visible wavelength range at a predetermined angle of incidence of at least 30%; a first adhesive layer disposed between the first glass layer and the reflective film to bond them together; a second adhesive layer disposed between the second glass layer and the reflective film and bonding them together, wherein the second adhesive layer is thicker than the first adhesive layer, such that a first major surface of the reflective film is separated from an outermost major surface of the first glass layer by a distance d1 and a second major surface of the reflective film is separated from an outermost major surface of the second glass layer by a distance d2, and 0.05≦d1 / d2≦0.9.

[0047] A second embodiment is the glass laminate of the first embodiment, wherein 0.05≦d1 / d2≦0.8, or 0.1≦d1 / d2≦0.8, or 0.2≦d1 / d2≦0.7.

[0048] A third embodiment is the glass laminate of the first or second embodiment, wherein the second adhesive layer is at least 2, 3, 5, 10, 20, 50, 100, or 200 times thicker than the first adhesive layer.

[0049] A fourth embodiment is the glass laminate of any one of the first to third embodiments, wherein the first adhesive layer has a thickness in the range of 1 micron to 75 microns, and the second adhesive layer has a thickness in the range of 300 microns to 1000 microns.

[0050] A fifth embodiment is the glass laminate of any one of the first to fourth embodiments, wherein the second glass layer is at least 1.5 times thicker than the first glass layer.

[0051] A sixth embodiment is the glass laminate of any one of the first to fifth embodiments, wherein the average reflectivity of the reflective film for a first polarization state within a predetermined visible wavelength range at a predetermined angle of incidence is at least 20%, and the average transmittance for the reflective film for a second polarization state within a predetermined visible wavelength range at a predetermined angle of incidence is at least 50%.

[0052] A seventh embodiment is a glass laminate comprising: first and second glass layers having substantially parallel outermost major surfaces; and a reflective film comprising a plurality of alternating polymer interference layers and asymmetrically disposed between the outermost major surfaces, whereby when a light source positioned within 2 m of the glass laminate projects a line onto the outermost major surface of the first glass layer along a first direction that forms an angle θ with respect to a normal to the glass laminate in the range of 30 degrees to 85 degrees, the line extending along a second direction orthogonal to a first plane defined by the first direction and the normal and having a projected luminance distribution about a center line of the projected line having a full width at half maximum of 0.05 degrees or less, a first portion of the projected line is reflected from the reflective film and a second portion of the projected line is reflected from the outermost major surface of the first glass layer, a reflected image of the line includes a primary reflected image portion defined by the reflected first portion and a first ghost portion defined by the reflected second portion, the first ghost portion substantially overlapping the primary reflected image portion.

[0053] An eighth embodiment is the glass laminate of the seventh embodiment, wherein a third portion of the projected line reflects from the outermost major surface of the second glass layer, and the reflected image of the line further includes a second ghost portion defined by the reflected third portion, the second ghost portion substantially overlapping the primary reflected image portion.

[0054] A ninth embodiment is the glass laminate of the seventh or eighth embodiment, wherein the reflected image has a reflected luminance distribution that has a maximum at a peak of the reflected luminance distribution and monotonically decreases in at least one lateral direction from the peak to an edge of the reflected image.

[0055] A tenth embodiment is the glass laminate of any one of the seventh to ninth embodiments, wherein the full width at half maximum of the projected line is 0.03 degrees or less, and the reflected image has a brightness angular distribution with a full width at half maximum of 0.1 degrees or less.

[0056] An eleventh embodiment is the glass laminate of any one of the seventh to tenth embodiments, wherein the second ghost portion has a brightness that is less than 0.6, 0.5, 0.4, 0.3, 0.2, 0.1, 0.05, or 0.01 times the brightness of the first ghost portion.

[0057] A twelfth embodiment is a glass laminate comprising: first and second glass layers having substantially parallel outermost major surfaces; and a reflective film, the reflective film including a plurality of alternating polymer interference layers and disposed and bonded between first and second glass layers through respective first and second adhesive layers, wherein the first adhesive layer has a thickness no greater than 0.6 times the thickness of the second adhesive layer, such that when a light source projects a plurality of parallel lines onto an outermost major surface of the first glass layer along a first direction that forms an angle θ with a normal to the glass laminate in a range of 30 degrees to 85 degrees, the plurality of parallel lines extending along a second direction orthogonal to a first plane defined by the first direction and the normal and spaced apart along a third direction within the first plane and orthogonal to the first direction, a first portion of each projected line is reflected from the reflective film, a reflected image of each line includes the reflected first portion, and each reflected image has an intensity distribution that defines a centerline of the reflected image, and the distribution of the angle α between the centerline of the reflected image and the second direction has a full width at half maximum of less than 3 degrees.

[0058] A thirteenth embodiment is the glass laminate of the twelfth embodiment, wherein the reflective film has an average reflectance of at least 15% for a first polarization state within a predetermined visible wavelength range at a predetermined angle of incidence, and an average transmittance of at least 30% for an orthogonal second polarization state within a predetermined visible wavelength range at a predetermined angel of incidence.

[0059] A fourteenth embodiment is the glass laminate of the twelfth or thirteenth embodiment, wherein the first adhesive layer has a thickness in the range of 1 micron to 75 microns, and the second adhesive layer has a thickness in the range of 300 microns to 1000 microns.

[0060] A fifteenth embodiment is the glass laminate of any one of the twelfth to fourteenth embodiments, wherein the full width at half maximum of the distribution of the angle α is less than 2 degrees, or less than 1.5 degrees, or less than 1.2 degrees.

[0061] Example Reflective Film WCF A reflective film, termed windshield combiner film (WCF), was fabricated by extruding and uniaxially orienting 275 alternating polymer layers plus two outermost skin layers, as broadly described in U.S. Patent No. 6,827,886 (Neavin et al.). The alternating polymer layers were oriented PET as the higher refractive index layer and crystalline PETg as the lower refractive index layer. Layer thicknesses were selected to produce reflectivity across the entire visible wavelength range from 400 nm to 700 nm. The film had an average reflectivity within the visible range at 60 degrees incidence of approximately 20% for p-polarized light and was substantially transparent for s-polarized light.

[0062] Example 1 The reflective film WCF was laminated between first and second 2.1 mm thick glass layers such that a 1 mil thick layer of 3M 8146 bonded the reflective film to the first glass layer and a 0.76 mm thick PVB layer (formed from two 0.38 mm thick PVB layers) bonded the reflective film to the second glass layer.

[0063] A line was projected onto the first glass layer of the glass laminate using an iPad (first generation) from Apple Inc. (Cupertino, CA) at an incident angle of approximately 65 degrees. The line image was two pixels wide. A PROMETRIC I8 imaging colorimeter available from Radiant Vision Systems (Redmond, WA) was used to determine the reflected luminance distribution as a function of angle from the central peak of the primary reflected image (e.g., angle φ in Figure 1B), which is shown in Figure 9. The primary reflected image had a full width at half maximum of approximately 0.02 degrees. A first ghost image was located approximately 0.08 degrees from the primary reflected image, and a second ghost image was located approximately -0.11 degrees from the primary reflected image.

[0064] Example 2 Example 2 was prepared and tested as described for Example 1, except that the first and second glass layers were each 1 mm thick. The resulting reflected luminance distributions are shown in Figures 10-11, respectively, as a function of angle (e.g., angle φ in Figure 1B) and location (e.g., x-coordinate in Figure 1A). The first and second ghost images substantially overlap with the primary reflected image.

[0065] Comparative Example C1 Comparative Example C1 was prepared and tested as described for Example 1, except that the first adhesive layer was a 0.76 mm thick PVB layer. The resulting reflected brightness distribution is shown as a function of location (x coordinate in FIG. 1A) in Figure 12. The first and second ghost images had sufficiently high brightness and were sufficiently displaced from the primary reflected image to cause an objectionable loss of image fidelity.

[0066] Examples 3 to 4 Example 3 was prepared as described for Example 1, except that the first adhesive layer was a 0.38 mm thick PVB layer. Example 4 was prepared as described for Example 1, except that the first glass layer was 3.2 mm thick. Using a thicker glass layer is expected to affect the location of ghost images, but is expected to have a negligible effect on line waviness.

[0067] Multiple parallel lines were projected onto the reflective film through the first glass layer of the glass laminates of Comparative Example C1, Example 3, and Example 4 at an angle of incidence to the glass laminate of approximately 55 degrees, and the reflected images were analyzed using a PROMETRIC colorimeter. Figures 13A-13C show the reflected images for Comparative Example C1, Example 3, and Example 4, respectively. Using the image analysis procedure outlined in "Experimental investigation of collagen waviness and orientation in the arterial adventitia using confocal laser scanning microscopy," Rezakhaniha et al., Biomech Model Mechanobiol, March 2012;11(3-4);461-73;doi:10.1007 / s10237-011-0325-z, the centerline tangent to each line was determined at a sufficient number of locations along each line, and the distribution of centerline tangent orientations was determined. The resulting distribution is plotted in Figure 14. The full width at half maximum for each distribution was determined and found to be 4.0 degrees, 1.9 degrees, and 1.0 degrees for Comparative Example C1, Example 3, and Example 4, respectively.

[0068] Any of the foregoing references, patents, or patent applications are incorporated herein by reference in their entirety in a consistent manner. In the event of any inconsistency or contradiction between any portion of the incorporated reference and this application, the information in the foregoing statement shall prevail.

[0069] Descriptions of elements in the figures should be understood to apply equally to corresponding elements in other figures unless otherwise indicated. While specific embodiments have been illustrated and described herein, those skilled in the art will recognize that various alternative and / or equivalent implementations may be substituted for the specific embodiments shown and described without departing from the scope of the present disclosure. This application is intended to cover any adaptations or variations of the specific embodiments described herein. Accordingly, the present disclosure is limited only by the claims and their equivalents.

Claims

1. A glass laminate comprising: first and second glass layers having substantially parallel outermost major surfaces facing away from each other; a reflective film having opposing first and second major surfaces and disposed between the first and second glass layers, the first and second major surfaces facing the respective first and second glass layers, the reflective film having an average reflectance for a first polarization state within a predetermined visible wavelength range at a predetermined angle of incidence of at least 15%, and an average transmittance for an orthogonal second polarization state within the predetermined visible wavelength range at the predetermined angle of incidence of at least 30%; a first adhesive layer disposed between the first glass layer and the reflective film to bond them together; a second adhesive layer disposed between the second glass layer and the reflective film and bonding them together, the second adhesive layer being thicker than the first adhesive layer, such that the first major surface of the reflective film is separated from the outermost major surface of the first glass layer by a distance d1 and the second major surface of the reflective film is separated from the outermost major surface of the second glass layer by a distance d2, and 0.05≦d1 / d2≦0.

9.

2. 2. The glass laminate of claim 1, wherein 0.1≦d1 / d2≦0.

8.

3. 3. The glass laminate of claim 1 or 2, wherein the second adhesive layer is at least twice as thick as the first adhesive layer.

4. 3. The glass laminate of claim 1, wherein the first adhesive layer has a thickness in the range of 1 micron to 75 microns and the second adhesive layer has a thickness in the range of 300 microns to 1000 microns.

5. 5. The glass laminate of claim 1, wherein the second glass layer is at least 1.5 times thicker than the first glass layer.

6. 6. The glass laminate of claim 1, wherein the average reflectivity of the reflective film for the first polarization state within the predetermined visible wavelength range at the predetermined angle of incidence is at least 20%, and the average transmittance for the reflective film for the second polarization state within the predetermined visible wavelength range at the predetermined angle of incidence is at least 50%.

7. A glass laminate comprising: first and second glass layers having substantially parallel outermost major surfaces; a reflective film comprising a plurality of alternating polymer interference layers and asymmetrically disposed between the outermost major surfaces, whereby when a light source positioned within 2 meters of the glass laminate projects a line onto the outermost major surface of the first glass layer along a first direction that forms an angle θ with respect to a normal to the glass laminate in a range of 30 degrees to 85 degrees, the line extending along a second direction orthogonal to a first plane defined by the first direction and the normal and having a projected luminance distribution about a center line of the projected line that has a full width at half maximum of 0.05 degrees or less, a first portion of the projected line is reflected from the reflective film, a second portion of the projected line is reflected from the outermost major surface of the first glass layer, a reflected image of the line includes a primary reflected image portion defined by the reflected first portion and a first ghost portion defined by the reflected second portion, and the first ghost portion substantially overlaps the primary reflected image portion.

8. 8. The glass laminate of claim 7, wherein a third portion of the projected line reflects from the outermost major surface of the second glass layer, and the reflected image of the line further includes a second ghost portion defined by the reflected third portion, the second ghost portion substantially overlapping the primary reflected image portion.

9. 9. The glass laminate of claim 7 or 8, wherein the reflected image has a reflected luminance distribution having a maximum at a peak of the reflected luminance distribution and monotonically decreasing in at least one lateral direction from the peak to an edge of the reflected image.

10. 10. The glass laminate of claim 7, wherein the full width at half maximum of the projected line is 0.03 degrees or less, and the reflected image has a brightness angular distribution with a full width at half maximum of 0.1 degrees or less.

11. 11. The glass laminate of any one of claims 7 to 10, wherein the second ghost portion has a brightness that is less than 0.6 times the brightness of the first ghost portion.

12. A glass laminate comprising: first and second glass layers having substantially parallel outermost major surfaces; a reflective film comprising a plurality of alternating polymer interference layers disposed between and adhered to the first and second glass layers through respective first and second adhesive layers, the first adhesive layer having a thickness no greater than 0.6 times the thickness of the second adhesive layer, whereby a light source projects a plurality of parallel lines onto the outermost major surface of the first glass layer along a first direction that forms an angle θ with respect to a normal to the glass laminate in a range of 30 degrees to 85 degrees, the plurality of parallel lines projecting in the first direction. and extending along a second direction orthogonal to a first plane defined by the normal, and wherein when spaced apart along a third direction within the first plane and orthogonal to the first direction, a first portion of each projected line reflects from the reflective film, a reflected image of each line includes the reflected first portion, each reflected image has a luminance distribution defining a center line of the reflected image, and the distribution of angle α between the center line of the reflected image and the second direction has a full width at half maximum of less than 3 degrees.

13. 13. The glass laminate of claim 12, wherein the reflective film has an average reflectivity of at least 15% for a first polarization state within a predetermined visible wavelength range at a predetermined angle of incidence and an average transmittance of at least 30% for an orthogonal second polarization state within the predetermined visible wavelength range at the predetermined angel of incidence.

14. 14. The glass laminate of claim 12 or 13, wherein the first adhesive layer has a thickness in the range of 1 micron to 75 microns and the second adhesive layer has a thickness in the range of 300 microns to 1000 microns.

15. 15. The glass laminate of claim 12, wherein the full width at half maximum of the distribution of angles α is less than 2 degrees.

Images