Laminated glass, heads-up display system

Abstract

In a laminated glass having a P-polarized light reflecting film, ghost is suppressed and visibility of a HUD image is improved. The laminated glass is a laminated glass having a first glass sheet, a second glass sheet, and an interlayer film between the first glass sheet and the second glass sheet and bonding the first glass sheet and the second glass sheet, the laminated glass having a first region used in a head-up display in a part thereof, when a face of the first glass sheet on a side opposite to the interlayer film is set to 4 faces, a face of the first glass sheet on a side of the interlayer film is set to 3 faces, a face of the second glass sheet on a side of the interlayer film is set to 2 faces, and a face of the second glass sheet on a side opposite to the interlayer film is set to 1 face, in the first region, a P-polarized light reflecting film is provided on the 4 faces, a light absorbing layer is provided closer to the 1 face side than the P-polarized light reflecting film, a total of a visible light transmittance of the P-polarized light reflecting film and a visible light transmittance of the light absorbing layer is set to Tv%, a total of a visible light reflectance of the P-polarized light reflecting film and a visible light reflectance of the light absorbing layer is set to Rv%, and an absorbance A = 100 - Tv - Rv [%] is satisfied, when A ≥ 85% is satisfied, a total of a P-polarized light reflectance of the P-polarized light reflecting film and a P-polarized light reflectance of the light absorbing layer in a case where P-polarized light is incident at an incident angle of 57 degrees from the P-polarized light reflecting film side is set to Rvp%, and Rvp ≥ 5% is satisfied.

Description

Technical Field

[0001] This invention relates to a laminated glass head-up display system. Background Technology

[0002] In recent years, the adoption of head-up displays (HUDs) that reflect images onto the windshield of a vehicle to display specific information in the driver's field of vision has been progressing. One of the challenges of HUDs is improving the visibility of the HUD image, and therefore, efforts are being made to reduce ghosting.

[0003] As an example, the following technology can be cited: applying a P-polarized light reflective film, which is composed of a coating or film that reflects P-polarized light, to the laminated glass. By allowing P-polarized light to be incident on the laminated glass, ghosting is suppressed, and the HUD image is clearly projected by the reflection mainly by the P-polarized light reflective film.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Publication No. 2017-538141 Summary of the Invention

[0007] The technical problem that the invention aims to solve

[0008] However, in the above technology, when the incident angle of P-polarized light incident on the laminated glass deviates from 57 degrees (Brewster angle), the reflection on the outer or inner main surface of the laminated glass will increase, the ghosting will become more noticeable, and the visibility of the HUD image will decrease.

[0009] The present invention was made in view of the above-mentioned problems, and its object is to improve the visibility of HUD images by suppressing ghosting in laminated glass with a P-polarized light reflective film.

[0010] means of solving technical problems

[0011] One disclosed embodiment of the laminated glass comprises a first glass plate, a second glass plate, and an interlayer film located between and bonding the first and second glass plates. The laminated glass has a first region therein for use in a head-up display. When the surface of the first glass plate opposite to the interlayer film is designated as a fourth surface, the surface of the first glass plate on the side of the interlayer film is designated as a third surface, the surface of the second glass plate on the side of the interlayer film is designated as a second surface, and the surface of the second glass plate opposite to the interlayer film is designated as a single surface, in the first region, on the fourth surface… A P-polarized light reflective film is provided, and a light absorption layer is provided closer to the I-side than the P-polarized light reflective film. The sum of the visible light transmittance of the P-polarized light reflective film and the visible light transmittance of the light absorption layer is set as Tv%, and the sum of the visible light reflectance of the P-polarized light reflective film and the visible light reflectance of the light absorption layer is set as Rv%. When the absorption rate A = 100 - Tv - Rv[%], A ≥ 85% is satisfied. When the sum of the P-polarized light reflectance of the P-polarized light reflective film and the P-polarized light reflectance of the light absorption layer is set as Rvp% when P-polarized light is incident from the P-polarized light reflective film side at an incident angle of 57 degrees, Rvp ≥ 5% is satisfied.

[0012] Invention Effects

[0013] One disclosed embodiment can suppress ghosting in laminated glass with a P-polarized reflective film, thereby improving the visibility of the HUD image. Attached Figure Description

[0014] Figure 1 This is a schematic diagram illustrating the HUD system of the first embodiment.

[0015] Figure 2 A and Figure 2 B is a diagram illustrating the laminated glass according to the first embodiment. Figure 2 Figure A is a schematic diagram showing the view from inside the train car to the outside through the laminated glass. Figure 2 B is along Figure 2 A partially enlarged sectional view of line AA of A.

[0016] Figure 3 This is a diagram illustrating a modified example of the first embodiment of laminated glass.

[0017] Figure 4 A and Figure 4 B is a diagram illustrating the laminated glass according to the second embodiment. Figure 4 Figure A is a schematic diagram showing the view from inside the train car to the outside through the laminated glass. Figure 4 B is along Figure 4A partially enlarged sectional view of line BB of A. Detailed Implementation

[0018] The embodiments of the invention will now be described with reference to the accompanying drawings. In the drawings, the same components are labeled with the same symbols, and sometimes repeated descriptions are omitted. Furthermore, in the drawings, the size and shape of some parts are sometimes exaggerated to facilitate understanding of the invention.

[0019] In addition, "vehicle" typically refers to automobiles, but also includes moving bodies such as trams, ships, and airplanes that can be fitted with laminated glass.

[0020] In addition, a top view refers to observing an object from the direction of the normal line passing through the center of gravity of the object's main surface; the shape seen at this time is called a planar shape.

[0021] Additionally, the markings "up" and "down" refer to the top and bottom when the laminated glass is installed on the vehicle.

[0022] In addition, the outermost edge of a component is defined as the "periphery", and the area within the component with a width inscribed in the "periphery" is called the "periphery portion".

[0023] <First Implementation Method>

[0024] [HUD System]

[0025] Figure 1 This is a schematic diagram illustrating the HUD system of the first embodiment. Figure 1 The HUD system 1 shown includes a laminated glass 10, a light source 50, a first optical system 60, an image display element 70, a second optical system 80, and a concave mirror 90. The HUD system 1 is a vehicle head-up display system viewed from the perspective of a passenger at viewpoint P, where a virtual image V is displayed on the outside of the laminated glass 10. Furthermore, the first optical system 60 and the second optical system 80 in the HUD system 1 can be configured as needed.

[0026] The laminated glass 10 is, for example, a windshield for a vehicle, where P-polarized visible light is incident from the inside of the vehicle. The laminated glass 10 has a P-polarized reflective film 15 in the area where the P-polarized visible light is incident, as reflected by the concave mirror 90.

[0027] Light source 50 is a source of visible light that emits P-polarized light, such as a light-emitting diode or a laser. Light source 50 may also include optical components such as polarizers or lenses that convert S-polarized light into P-polarized light. Light source 50 may, for example, consist of three light sources: a red light source, a green light source, and a blue light source.

[0028] The first optical system 60 is, for example, composed of a prism or lens that combines light emitted from multiple light sources. The image display element 70 is an element that generates an intermediate image, such as a liquid crystal display element or an organic light-emitting element. The second optical system 80 is, for example, composed of a lens or a mirror. The concave mirror 90 is an optical component that reflects the intermediate image using a reflective surface with a specific curvature. The concave mirror 90 is positioned closest to the laminated glass 10 among the optical components in the optical path between the light source 50 and the laminated glass 10.

[0029] In HUD system 1, light emitted from light source 50 reaches image display element 70 via first optical system 60, forming an intermediate image at image display element 70. The intermediate image formed by image display element 70 is magnified by second optical system 80 and concave mirror 90, and then illuminates the P-polarized light reflective film 15 of laminated glass 10. The intermediate image illuminating the P-polarized light reflective film 15 is mainly reflected and guided to the occupant's viewpoint P by the P-polarized light reflective film 15. The occupant, for example, is the driver of the vehicle, and perceives the intermediate image as a virtual image V (HUD image) in front of the laminated glass 10.

[0030] Figure 1 In this context, the symbol θ represents the angle of incidence when visible light from the P-polarized light emitted from the light source 50 is incident on the P-polarized reflective film 15 via a specific optical system. The angle of incidence θ can be 57 degrees (Brewster's angle), greater than 57 degrees, or less than 57 degrees. In the HUD system 1, as described later, even when the angle of incidence θ is greater than 57 degrees, a sufficiently bright main image and suppressed ghosting can be obtained. Furthermore, when the angle of incidence of light from the light source 50 onto the P-polarized reflective film 15 is greater than 57 degrees, the effect of suppressing ghosting is enhanced, which is therefore preferable. Furthermore, it is preferable that the angle of incidence of light from the light source 50 onto the P-polarized reflective film 15 is less than 47 degrees or greater than 62 degrees.

[0031] Furthermore, the HUD system 1 only needs to have a laminated glass 10 and a light source 50, and other structures can be arbitrary. The HUD system 1 can also be a laser scanning method that scans lasers using an optical scanning unit composed of MEMS (Micro Electro Mechanical Systems).

[0032] Laminated glass

[0033] Figure 2 A and Figure 2 B is a diagram illustrating the laminated glass according to the first embodiment. Figure 2 Figure A is a schematic diagram showing the view from inside the train car to the outside through the laminated glass. Figure 2 B is along Figure 2 A partially enlarged sectional view of line AA of A.

[0034] like Figure 2 A and Figure 2 As shown in Figure B, the laminated glass 10 is a vehicle-grade laminated glass having a first glass plate 11, a second glass plate 12, an interlayer film 13, a shielding layer 14, a P-polarized light reflective film 15, and a light-absorbing layer 18. The laminated glass 10 can be used, for example, in vehicle windshields.

[0035] The first glass panel 11 and the second glass panel 12 are bonded together by an interlayer film 13. The first glass panel 11 is positioned on the first side, becoming the interior side of the vehicle, when the laminated glass 10 is installed on the vehicle. The second glass panel 12 is positioned on the second side, becoming the exterior side of the vehicle, when the laminated glass 10 is installed on the vehicle. Additionally, a shielding layer 14 is provided as needed.

[0036] Laminated glass 10 may be, for example, a hyperboloid shape that bends in both the vertical and horizontal directions when mounted on a vehicle. However, a hyperboloid shape is not limited to shapes that bend in both the vertical and horizontal directions when mounted on a vehicle, but may also include shapes that bend in more than two different directions. Alternatively, laminated glass 10 may be a single-curved shape that bends only in the vertical or horizontal direction when mounted on a vehicle. However, a single-curved shape is not limited to shapes that bend only in the vertical or horizontal direction when mounted on a vehicle, but may also include shapes that bend in only one direction.

[0037] The laminated glass 10 is preferably curved in a manner that bulges outwards from the vehicle. That is, the second glass panel 12 is preferably curved in a manner that bulges outwards from the side opposite to the interlayer film 13, and the first glass panel 11 is preferably curved in a manner that bulges outwards from the interlayer film 13. Furthermore, Figure 2 In A, the laminated glass 10 is trapezoidal when viewed from above, but the laminated glass 10 is not limited to a trapezoidal shape; it can also be any shape, including rectangles.

[0038] The first glass panel 11 is the interior glass panel of the vehicle (first side) when the laminated glass 10 is installed on the vehicle. The second glass panel 12 is the exterior glass panel of the vehicle (second side) when the laminated glass 10 is installed on the vehicle.

[0039] In the laminated glass 10, the minimum radius of curvature is preferably between 500 mm and 100,000 mm. The radii of curvature of the first glass plate 11 and the second glass plate 12 may be the same or different. When the radii of curvature of the first glass plate 11 and the second glass plate 12 are different, it is preferable that the radius of curvature of the first glass plate 11 is smaller than that of the second glass plate 12.

[0040] The first glass plate 11 and the second glass plate 12 are a pair of glass plates facing each other. An intermediate film 13 is located between the pair of glass plates. The first glass plate 11 and the second glass plate 12 are fixed in a state of clamping the intermediate film 13. The intermediate film 13 is a film that joins the first glass plate 11 and the second glass plate 12.

[0041] The outer peripheral side of the interlayer film 13 is preferably edge-treated. That is, the outer peripheral side of the interlayer film 13 is preferably treated so that it does not protrude significantly from the outer peripheral side of the first glass plate 11 and the second glass plate 12. It is preferred from the perspective of not impairing the appearance if the amount of the outer peripheral side of the first glass plate 11 and the second glass plate 12 protruding from the outer peripheral side of the interlayer film 13 is less than 150 μm. The details of the first glass plate 11, the second glass plate 12 and the interlayer film 13 will be described in detail later.

[0042] The shielding layer 14 is an opaque layer, for example, formed in a strip along the periphery of the laminated glass 10. The shielding layer 14 may be, for example, an opaque colored ceramic layer. The color of the shielding layer is arbitrary, but dark colors such as black, brown, gray, and dark navy blue are preferred, with black being more preferable. The shielding layer 14 may also be a colored interlayer film or a colored film with light-blocking properties, a combination of a colored interlayer film and a colored ceramic layer, or a layer with light-switching functions. The colored film may be integrated with an infrared reflective film, etc.

[0043] The width of the shielding layer 14 when viewed from above is, for example, about 10 mm to 250 mm, preferably 20 mm to 220 mm, and more preferably 30 mm to 200 mm. The presence of an opaque shielding layer 14 in the laminated glass 10 can prevent the adhesive made of resins such as polyurethane that holds the periphery of the laminated glass 10 to the vehicle body from deteriorating due to ultraviolet radiation.

[0044] The masking layer 14 can be formed, for example, by applying a ceramic color paste containing molten glass frit with black pigment to a glass plate by screen printing and then firing it. The method of forming the masking layer is not limited to this. The masking layer 14 can also be formed, for example, by applying an organic ink containing black or dark pigment to a glass plate by screen printing and then drying it.

[0045] The shielding layer 14 may be provided only on the periphery of the interior main surface of the second glass panel 12. However, the shielding layer 14 may also be provided only on the periphery of the interior main surface of the first glass panel 11, or it may be provided on both the periphery of the interior main surface of the second glass panel 12 and the periphery of the interior main surface of the first glass panel 11. In the case where the shielding layer 14 is provided on the periphery of the interior main surface of the first glass panel 11, the shielding layer 14 is located outside the HUD display area R.

[0046] In the laminated glass 10, the HUD display area R used in the HUD is defined in the area surrounded by the shielding layer 14 when viewed from above. In addition, the HUD display area R is not limited to one place. For example, in the area surrounded by the shielding layer 14 when viewed from above, it can be separately arranged in multiple locations in the vertical direction, or it can be separately arranged in multiple locations in the horizontal direction.

[0047] The HUD display area R is a display area that reflects projected images from inside the vehicle to display information. The HUD display area R is the range on the laminated glass 10 illuminated by light from the light source 50 when the HUD display position is moved within the field of view based on the SAE International Surface Vehicle Standard J1757-2 (2018). The HUD display area R can be positioned anywhere within a width of 400mm at the lower edge of the laminated glass 10.

[0048] The HUD display area R is located, for example, below the laminated glass 10. In the HUD display area R and its surrounding area, a P-polarized light reflective film 15 is disposed on the inner side main surface of the first glass panel 11. The P-polarized light reflective film 15 can be disposed to cover the entire HUD display area R, or it can be disposed on the entire laminated glass 10. It is preferable to dispose of the P-polarized light reflective film 15 on the entire laminated glass 10 or to have the end of the P-polarized light reflective film 15 located on the shielding layer 14, from the perspective of having an indistinct boundary between the area where the P-polarized light reflective film 15 is disposed and its surrounding area.

[0049] The P-polarized light reflective film 15 is a film that reflects visible light from the P-polarized light incident on the concave mirror 90 towards the inside of the vehicle. For example, it is a P-polarized light reflective coating applied to the main surface of the inside of the first glass plate 11. Alternatively, a P-polarized light reflective film can be used as the P-polarized light reflective film 15 and bonded to the main surface of the inside of the first glass plate 11 via an adhesive layer. The P-polarized light reflective film 15 is transparent to visible light.

[0050] As the P-polarized light reflective film 15, for example, a birefringent interference type polarizer composed of a polymer multilayer film made of two or more polymers with different refractive indices, a polarizer with a finely textured structure known as a wire grid type, or a film containing a polarizer made of a cholesteric liquid crystal layer can be used. When a P-polarized light reflective film is used as the P-polarized light reflective film 15, the thickness of the P-polarized light reflective film is preferably 25 μm or more and 200 μm or less. The thickness of the P-polarized light reflective film is more preferably 150 μm or less, and even more preferably 100 μm or less.

[0051] Compared to using a P-polarized reflective film, using a P-polarized reflective coating as the P-polarized reflective film 15 offers superior visibility in low-brightness conditions such as at night or at wider viewing angles. Furthermore, the P-polarized reflective coating is preferable in terms of ease of control over film thickness and the ability to smoothly smooth the reflective surface, thus minimizing distortion of the HUD image.

[0052] Furthermore, when using a P-polarized reflective coating, since a black ceramic paste is applied to the coated glass plate before firing and bending, the appropriate type of black ceramic layer can be selected based on the bending process or the composition of the coating to achieve the desired optical performance and chromaticity. In particular, depending on the type of laminated glass, there are cases where both the inner glass plate (with a P-polarized reflective coating) and the outer glass plate (with black ceramic layers on both sides) are bent simultaneously. In this case, the preferred bending conditions vary depending on the characteristics of the coating, thus providing the advantage of selecting a black ceramic material suitable for these bending conditions.

[0053] When using a P-polarized light reflective coating as the P-polarized light reflective film 15, the film thickness of the P-polarized light reflective coating is, for example, 50 nm or more and 500 nm or less.

[0054] Examples of P-polarized light reflective coatings include films with a certain degree of P-polarized light reflectivity, such as films with a stacked structure of high-refractive-index films and low-refractive-index films, or Low-e films. Among these, for the structure of the present invention, from the perspective of maintaining high P-polarized light reflectivity, a film with a stacked structure of high-refractive-index films and low-refractive-index films is preferred.

[0055] The refractive index of the high-refractive-index film at a wavelength of 550 nm is 1.8 or higher, or 1.9 or higher, or 2.0 or higher, or 2.1 or higher, preferably 2.5 or lower. The refractive index of the low-refractive-index film at a wavelength of 550 nm is typically less than 1.8, or 1.7 or lower, or 1.6 or lower, preferably 1.2 or higher.

[0056] Specifically, the high refractive index film preferably includes at least one of the following.

[0057] Oxides of Zr, Nb or Sn, mixed oxides of Ti, Zr, Nb, Si, Sb, Sn, Zn or In, nitrides of Si or Zr, or mixed nitrides of Si or Zr.

[0058] The low refractive index film preferably contains at least one of the following.

[0059] Silicon oxide, silicon oxynitride, silicon oxycarbide, or mixtures thereof, such as mixed oxides of silicon and aluminum, or mixed oxides of silicon and zirconium.

[0060] The first layer of the high refractive index film is optionally composed of one or more sub-layers. The thickness (geometric thickness) of the first layer of the high refractive index film is preferably 50 nm to 100 nm, and particularly preferably 60 nm to 80 nm. The first layer of the low refractive index film is optionally composed of one or more sub-layers. The thickness (geometric thickness) of the first layer of the low refractive index film is preferably 70 nm to 160 nm, and particularly preferably 80 nm to 120 nm.

[0061] P-polarized reflective coatings can be formed on the surface of a glass plate, for example, by sputtering or CVD.

[0062] Typically, in a HUD system with a P-polarized reflective film, a light source or optical system is positioned so that the incident angle of the P-polarized light incident on the reflective film is approximately 57 degrees. However, due to limitations in the placement of the light source or optical system within the vehicle, the incident angle θ may sometimes deviate from 57 degrees.

[0063] In HUD system 1, the HUD display area R tends to have a larger incident angle θ as the mounting angle of the laminated glass 10 onto the vehicle becomes smaller. Visible light of P-polarized light incident from the inside of the vehicle onto the laminated glass 10 is refracted and reaches the outer side of the second glass panel 12. If the incident angle θ deviates from the Brewster angle (57 degrees), the amount of light reflected from that surface increases. Specifically, when the incident angle θ reaches 62 degrees or more (e.g., 67 or 72 degrees), the amount of light reflected from the outer side of the second glass panel 12 increases, making it easier to see. Therefore, when visible light of P-polarized light deviates from the Brewster angle and incident on the laminated glass 10, sometimes a virtual image separates and is seen. This separated and seen image is a ghost image, and if a ghost image occurs, the visibility of the HUD image decreases. Furthermore, when the incident angle θ decreases, for example, to below 47 degrees, the same ghosting problem becomes more pronounced.

[0064] Therefore, in the laminated glass 10, to suppress ghosting even when the incident angle θ deviates by 57 degrees, a light-absorbing layer 18 is disposed in the HUD display area R closer to the outer side of the vehicle than the P-polarized reflective film 15. In other words, the light-absorbing layer 18 is disposed at a position closer to the outer side of the vehicle than the P-polarized reflective film 15, where it completely overlaps with the P-polarized reflective film 15 when viewed from inside the vehicle. The light-absorbing layer 18 can be disposed, for example, on the inner side main surface of the second glass panel 12. The light-absorbing layer 18 can also be disposed on the outer side main surface of the first glass panel 11. The light-absorbing layer 18 can be encapsulated in the interlayer film 13. The light-absorbing layer 18 can also be arranged to be exposed around the HUD display area R.

[0065] If the side of the first glass plate 11 opposite to the intermediate film 13 is designated as a 4-sided surface, the side of the first glass plate 11 with the intermediate film 13 side is designated as a 3-sided surface, the side of the second glass plate 12 with the intermediate film 13 side is designated as a 2-sided surface, and the side of the second glass plate 12 opposite to the intermediate film 13 is designated as a 1-sided surface, then in the HUD display area R, a P-polarized light reflective film is provided on the 4-sided surface, and a light absorption layer 18 is provided at any part of the laminated glass 10 in a direction closer to the 1-sided surface than the P-polarized light reflective film 15. Figure 2 In example B, a P-polarized light reflective film 15 is set on surface 4 in the HUD display area R, and a light absorption layer 18 is set on surface 2.

[0066] The light-absorbing layer 18 can be, for example, an opaque colored ceramic layer similar to the shielding layer 14. In this case, the color is arbitrary, but dark colors such as black, brown, gray, and dark navy blue are preferred, with black being more preferable. In the material of the light-absorbing layer, it is preferable to mix an inorganic welding component and an inorganic powder component. Specifically, examples of inorganic welding components include Bi2O3-SiO2 systems and ZnO-SiO2 systems, while examples of inorganic powder components include MnO2 systems, Al2O3 systems, and TiO2 systems. The weight ratio of the inorganic welding component to the inorganic powder component is preferably 80:20 to 60:40. It is preferable that the light-absorbing layer material is a black ceramic paste (Bi2O3-SiO2 system) with an inorganic welding component and an MnO2 system with an inorganic powder component, containing an inorganic welding component to inorganic powder component in a weight ratio of 80:20 to 60:40, from the perspective of further enhancing the effects of the present invention.

[0067] The light-absorbing layer 18 can also be a smoke film. The light-absorbing layer 18 can also be a layer with dimming capabilities. Examples of layers with dimming capabilities include suspended particle devices (SPDs), polymer-dispersed liquid crystals (PDLCs), and polymer-networked liquid crystals (PNLCs). For example, a layer with dimming capabilities can be encapsulated within the intermediate film 13.

[0068] Alternatively, when the shielding layer 14 is disposed on the periphery of both sides, and the light-absorbing layer is disposed on both sides using the same material as the shielding layer 14, it is also possible to achieve the same effect as... Figure 3 As shown in the laminated glass 10A, the light-absorbing layer 14A is formed continuously with the shielding layer 14. In other words, the shielding layer 14 can be locally widened to form the light-absorbing layer 14A. Therefore, a separate process for forming the light-absorbing layer 14A is unnecessary, thus simplifying the manufacturing process of the laminated glass 10. Furthermore, in Figure 3 In this case, the area below the HUD display area R can also be located within the shielding layer 14.

[0069] In the laminated glass 10, the sum of the visible light transmittance of the P-polarized reflective film 15 and the visible light transmittance of the light absorption layer 18 is defined as Tv%, and the sum of the visible light reflectance of the P-polarized reflective film 15 and the visible light reflectance of the light absorption layer 18 is defined as Rv%. When the absorptivity A = 100 - Tv - Rv [%), A ≥ 85% is satisfied. The absorptivity A preferably satisfies A ≥ 90%, and more preferably A ≥ 95%. In addition, the visible light transmittance and visible light reflectance can be measured according to the method according to JIS R 3106:2019. Furthermore, the sum of the visible light transmittance of the P-polarized reflective film 15 and the visible light transmittance of the light absorption layer 18, Tv, and the sum of the visible light reflectance of the P-polarized reflective film 15 and the visible light reflectance of the light absorption layer 18, Rv, are values ​​measured in the laminated glass 10 comprising the first glass plate 11, the second glass plate 12, and the intermediate film 13. These values ​​were obtained by measuring the spectral transmittance and spectral reflectance as described in JIS R 3106:2019 using visible light as the incident light, and then calculating them according to the methods for calculating visible light transmittance and visible light reflectance as described in JIS R 3106:2019.

[0070] Furthermore, in the laminated glass 10, when P-polarized light is incident from the P-polarized reflective film 15 at an incident angle θ of 57 degrees, the sum of the P-polarized reflectivity of the P-polarized reflective film 15 and the P-polarized reflectivity of the light absorption layer 18 is set as Rvp%, which satisfies Rvp ≥ 5%. Rvp preferably satisfies Rvp ≥ 7%, and more preferably Rvp ≥ 10%. In addition, Rvp is calculated by using a multi-angle spectrometer (e.g., a combination of an Agilent Cary 7000 and a multi-angle variable automatic measurement unit), under the condition that the incident angle of the light source relative to the laminated glass 10 reaches 57 degrees, and a polarizer is installed on the light source to adjust the composition of the light incident on the laminated glass 10 to P-polarized light, the spectrophotometric reflectivity is measured, and then calculated according to the visible light reflectivity calculation method described in JIS R3106:2019.

[0071] In this way, in the laminated glass 10, within the HUD display area R, a light-absorbing layer 18 is disposed closer to the outer edge of the vehicle than the P-polarized reflective film 15, resulting in an absorptivity A of 85% or higher. This reduces reflections on the surface closer to the outer edge of the vehicle than the P-polarized reflective film 15, even when the incident angle θ deviates from 57 degrees, thus suppressing ghosting. An absorptivity A of 90% or higher further suppresses ghosting, and an absorptivity A of 95% or higher further suppresses ghosting. The laminated glass 10 is particularly effective in suppressing ghosting when the incident angle θ deviates significantly from 57 degrees to 62 degrees or higher, for example, 62 degrees, 67 degrees, or 72 degrees. The same applies to incident angles θ below 47 degrees.

[0072] In addition, in the laminated glass 10, by arranging the light absorption layer 18 closer to the outer side of the vehicle than the P-polarized light reflective film 15, the contrast of the HUD image is increased and the visibility of the HUD image is improved.

[0073] Furthermore, in the laminated glass 10, when P-polarized light is incident at an angle of incidence θ of 57 degrees, the relative vp (Rvp) is greater than 5%, thus the main image becomes sufficiently bright, and the visibility of the HUD image is improved. When P-polarized light is incident at an angle of incidence θ of 57 degrees, if the Rvp is greater than 7%, the main image becomes even brighter, and the visibility of the HUD image is further improved. When P-polarized light is incident at an angle of incidence θ of 57 degrees, if the Rvp is greater than 10%, the main image becomes even brighter, and the visibility of the HUD image is improved even further.

[0074] Furthermore, in the laminated glass 10, when P-polarized light is incident from the P-polarized light reflector 15 side at an incident angle θ of 57 degrees, and the chromaticity of the light reflected by the P-polarized light reflector 15 and the light absorption layer 18 is set as a* and b*, it is preferable that a* ≤ 10 and b* ≤ 10. This results in a neutral chromaticity for the HUD image. More preferably, a* ≤ 7 and b* ≤ 7; even more preferably, a* ≤ 5 and b* ≤ 5. This further neutralizes the chromaticity of the HUD image. Additionally, the chromaticity (a*, b*) is the chromaticity value specified in JIS Z8781-4:2013, measured under a D65 light source.

[0075] Furthermore, in HUD system 1, it is preferable that the HUD image is not displayed at the boundary of the light absorption layer 18 and its surrounding area. This is to prevent HUD image distortion.

[0076] The first glass plate 11, the second glass plate 12, and the intermediate film 13 will be described in detail below.

[0077] [glass plate]

[0078] The first glass plate 11 and the second glass plate 12 can be inorganic glass or organic glass. As inorganic glass, examples include soda-lime glass, aluminosilicate glass, borosilicate glass, alkali-free glass, quartz glass, etc., with no particular limitation. From the viewpoint of scratch resistance, the second glass plate 12 located outside the laminated glass 10 is preferably inorganic glass, and from the viewpoint of formability, soda-lime glass is preferred. When the first glass plate 11 and the second glass plate 12 are soda-lime glass, transparent glass, green glass containing a specified amount or more of iron, and UV-blocking green glass are preferred.

[0079] Inorganic glass can be either unstrengthened glass or strengthened glass. Unstrengthened glass is made by forming molten glass into a sheet and then annealing it. Strengthened glass is made by forming a compressive stress layer on the surface of unstrengthened glass.

[0080] Tempered glass can be either physically strengthened glass (such as air-cooled strengthened glass) or chemically strengthened glass. In the case of physically strengthened glass, the glass sheet can be rapidly cooled from a temperature near its softening point during bending and forming, except for annealing operations. The temperature difference between the glass surface and the interior of the glass creates a compressive stress layer on the glass surface, thereby strengthening the glass surface.

[0081] In the case of chemically strengthened glass, for example, compressive stress can be generated on the glass surface by ion exchange after bending and forming, thereby strengthening the glass surface. Alternatively, glass that absorbs ultraviolet or infrared radiation can be used. Furthermore, the first glass plate 11 and the second glass plate 12 are preferably transparent, but glass plates that are colored to the extent that they do not impair transparency can also be used.

[0082] On the other hand, examples of materials used for acrylic glass include polycarbonate, polymethyl methacrylate and other acrylic resins, polyvinyl chloride and polystyrene and other transparent resins.

[0083] The first glass plate 11 and the second glass plate 12 are not limited to trapezoidal or rectangular shapes, but can also be of various shapes and processed into curvatures. The bending and forming of the first glass plate 11 and the second glass plate 12 can be carried out by gravity forming, pressure forming, roll forming, etc. There are no particular limitations on the forming method of the first glass plate 11 and the second glass plate 12. For example, in the case of inorganic glass, glass plates formed by float glass or the like are preferred.

[0084] The thickness of the second glass plate 12 at its thinnest point is preferably 1.1 mm to 3 mm. A thickness of 1.1 mm or more provides sufficient strength for resistance to flying stones and other defects. A thickness of 3 mm or less ensures that the mass of the laminated glass 10 does not become excessive, which is preferable from the perspective of vehicle fuel consumption. More preferably, the thickness of the second glass plate 12 at its thinnest point is 1.8 mm to 2.8 mm, even more preferably 1.8 mm to 2.6 mm, further preferably 1.8 mm to 2.2 mm, and even more preferably 1.8 mm to 2.1 mm.

[0085] The thickness of the first glass plate 11 is preferably between 0.3 mm and 2.3 mm. A thickness of 0.3 mm or more ensures good operability, while a thickness of 2.3 mm or less prevents excessive weight gain.

[0086] Furthermore, if the thickness of the first glass plate 11 is not suitable, and two pieces of glass with particularly deep curvature are used as the first glass plate 11 and the second glass plate 12 for forming, the shapes of these two pieces will be mismatched, which will have a great impact on the glass quality, such as residual stress after pressing.

[0087] However, by making the thickness of the first glass plate 11 between 0.3 mm and 2.3 mm, glass quality such as residual stress can be maintained. Making the thickness of the first glass plate 11 between 0.3 mm and 2.3 mm is particularly effective in maintaining the glass quality of glass with deep bends. The thickness of the first glass plate 11 is more preferably between 0.5 mm and 2.2 mm, and even more preferably between 0.7 mm and 2.1 mm. Within this range, the aforementioned effects are more significant.

[0088] A coating with water-repellent, ultraviolet or infrared blocking functions, or a coating with low reflectivity and low emissivity, may also be provided on the outer side of the first glass plate 11 and / or the second glass plate 12. A coating with ultraviolet or infrared blocking, low emissivity, visible light absorption, or coloring properties may also be provided on the side of the first glass plate 11 and / or the second glass plate 12 that contacts the intermediate film 13.

[0089] When the first glass plate 11 and the second glass plate 12 are inorganic glass in a curved shape, the first glass plate 11 and the second glass plate 12 are bent into shape after being formed by float glass or the like, and before being bonded together by an intermediate film 13. The bending is performed by heating to soften the glass. The heating temperature of the glass during bending can be controlled in the range of approximately 550°C to 700°C.

[0090] [Intermediate membrane]

[0091] Thermoplastic resins are commonly used as the interlayer membrane 13. Examples of thermoplastic resins include plasticized polyvinyl acetal resins, plasticized polyvinyl chloride resins, saturated polyester resins, plasticized saturated polyester resins, polyurethane resins, plasticized polyurethane resins, ethylene-vinyl acetate copolymer resins, ethylene-ethyl acrylate copolymer resins, cycloolefin polymer resins, and ionomer resins, which have been conventionally used for this purpose. In addition, the resin composition containing modified block copolymer hydrogenates described in Japanese Patent No. 6065221 can also be used for the interlayer membrane 13.

[0092] Considering the excellent balance of various properties such as transparency, weather resistance, strength, adhesion, penetration resistance, impact energy absorption, moisture resistance, thermal insulation, and sound insulation, plasticized polyvinyl alcohol acetal resins are suitable. These thermoplastic resins can be used alone or in combination of two or more. The term "plasticized" in the context of plasticized polyvinyl alcohol acetal resins indicates that plasticization can be achieved by adding plasticizers. The same meaning applies to other plasticized resins.

[0093] However, when a specific object is encapsulated in the interlayer 13, depending on the type of object being encapsulated, the encapsulated material may deteriorate due to a specific plasticizer. In this case, it is preferable to use a resin that is substantially free of the plasticizer. Examples of plasticizer-free resins include ethylene-vinyl acetate copolymer resins.

[0094] Examples of polyvinyl alcohol acetal resins include polyvinyl alcohol formaldehyde resin obtained by reacting polyvinyl alcohol (PVA) with formaldehyde, polyvinyl alcohol acetal resin (in the narrow sense) obtained by reacting PVA with acetaldehyde, and polyvinyl alcohol butyral resin (PVB) obtained by reacting PVA with n-butyraldehyde. In particular, considering the excellent balance of various properties such as transparency, weather resistance, strength, adhesion, penetration resistance, impact energy absorption, moisture resistance, thermal insulation, and sound insulation, PVB is suitable. Polyvinyl alcohol acetal resins can be used alone or in combination of two or more types.

[0095] However, the material forming the intermediate film 13 is not limited to thermoplastic resins. Furthermore, the intermediate film 13 may also contain functional particles such as infrared absorbers, ultraviolet absorbers, and luminescent agents. Additionally, the intermediate film 13 may have a colored portion known as a light-shielding band. As for the coloring pigment used to form the colored portion, any pigment suitable for use in plastics and whose visible light transmittance of the colored portion is adjusted to below 40% can be used. Examples include organic coloring pigments such as azo, phthalocyanine, quinacridone, perylene, pyrene, dioxazine, anthraquinone, and isoindolinone pigments, or inorganic coloring pigments such as oxides, hydroxides, sulfides, chromic acid, sulfates, carbonates, silicates, phosphates, arsenates, ferrocyanides, carbon, and metal powders. These coloring pigments can be used alone or in combination of two or more.

[0096] The interlayer 13 can have multiple layers. For example, the interlayer 13 can have three or more layers. For example, by forming the interlayer with three or more layers and adjusting the plasticizer to make the shear modulus of several layers other than the two side layers smaller than that of the two side layers, the sound insulation of the laminated glass 10 can be improved. In this case, the shear modulus of the two side layers can be the same or different.

[0097] The thickness of the interlayer film 13 is preferably 0.5 mm or more at its thinnest point. Furthermore, when the interlayer film 13 has multiple layers, the thickness of the interlayer film 13 refers to the sum of the thicknesses of each layer. If the thickness of the thinnest point of the interlayer film 13 is 0.5 mm or more, the impact resistance required for laminated glass is sufficient. Additionally, the thickness of the interlayer film 13 is preferably 3 mm or less at its thickest point. If the maximum thickness of the interlayer film 13 is 3 mm or less, the mass of the laminated glass will not become excessive. The maximum thickness of the interlayer film 13 is more preferably 2.8 mm or less, and even more preferably 2.6 mm or less.

[0098] Furthermore, when the interlayer 13 has multiple layers, each layer of the interlayer 13 is preferably formed of the same material, but it may also be formed of different materials. However, from the viewpoint of adhesion to the first glass plate 11 and the second glass plate 12, or the functional materials incorporated into the laminated glass 10, it is preferable that the aforementioned materials be used for more than 50% of the thickness of the interlayer 13.

[0099] When manufacturing the interlayer film 13, for example, the aforementioned resin material for forming the interlayer film is appropriately selected, and extrusion molding is performed using an extruder in a heated molten state. The extrusion conditions, such as the extrusion speed of the extruder, are set to conditions that ensure uniformity. Then, the resin film obtained by extrusion molding is matched to the design of the laminated glass, for example, by stretching it as needed to give the upper and lower edges of the resin film curvature, thereby completing the interlayer film 13.

[0100] Laminated glass

[0101] The total thickness of the laminated glass 10 is preferably 2.8 mm or more and 10 mm or less. A total thickness of 2.8 mm or more ensures sufficient rigidity. In addition, a total thickness of 10 mm or less allows for sufficient transmittance while reducing haze.

[0102] On at least one side of the laminated glass 10, the plate deviation between the first glass plate 11 and the second glass plate 12 is preferably less than 1.5 mm, more preferably less than 1 mm. Here, the plate deviation between the first glass plate 11 and the second glass plate 12 refers to the deviation between the outer peripheral side surface of the first glass plate 11 and the outer peripheral side surface of the second glass plate 12 when viewed from above.

[0103] On at least one side of the laminated glass 10, it is preferable if the deviation between the first glass plate 11 and the second glass plate 12 is less than 1.5 mm, from the perspective of not impairing the appearance. On at least one side of the laminated glass 10, it is more preferable if the deviation between the first glass plate 11 and the second glass plate 12 is less than 1.0 mm, from the perspective of not impairing the appearance.

[0104] In manufacturing laminated glass 10, an interlayer film 13 is sandwiched between a first glass plate 11 and a second glass plate 12 to form a laminate. Then, the laminate is placed, for example, in a rubber bag, a rubber chamber, or a resin bag, and bonded under vacuum conditions controlled within a gauge pressure range of -100 kPa to -65 kPa and a temperature controlled within a range of approximately 70°C to 110°C. Appropriate heating conditions, temperature conditions, and lamination methods are selected.

[0105] Furthermore, for example, by performing a heat-pressurization bonding process under controlled conditions of 100°C to 150°C and 0.6 MPa to 1.5 MPa, a laminated glass 10 with superior durability can be obtained. However, depending on the circumstances, considering the simplification of the process and the characteristics of the material encapsulated in the laminated glass 10, there are also cases where this heat-pressurization process is not used.

[0106] Alternatively, a method called "cold bending" can be used, in which one or both of the first glass plate 11 or the second glass plate 12 are joined together in a state of mutual elastic deformation. Cold bending can be achieved by using a laminate consisting of a first glass plate 11, an intermediate film 13, and a second glass plate 12 temporarily fixed with adhesive tape or other means, as well as conventionally known pre-compression devices such as clamping rollers, rubber bags, rubber chambers, and autoclaves.

[0107] Without impairing the effectiveness of this application, the laminated glass 10 may, in addition to the interlayer film 13, have films or devices with functions such as heating wires, infrared reflection, light emission, power generation, dimming, touch screen, visible light reflection, scattering, decoration, and absorption between the first glass plate 11 and the second glass plate 12. Furthermore, the laminated glass 10 may have films with functions such as anti-fogging, water repellency, heat insulation, and low reflection on its surface. Additionally, the laminated glass 10 may also have films with functions such as heat insulation and heat generation on the outer side of the first glass plate 11 or the inner side of the second glass plate 12.

[0108] <Second Implementation Method>

[0109] In the second embodiment, an example is shown where the laminated glass in the HUD system of the first embodiment has a wedge-shaped cross-section. Furthermore, in the second embodiment, descriptions of structural parts identical to those in the already described embodiments are sometimes omitted.

[0110] Figure 4 A and Figure 4 B is a diagram illustrating the laminated glass according to the second embodiment. Figure 4 Figure A is a schematic diagram showing the view from inside the train car to the outside through the laminated glass. Figure 4 B is along Figure 4 A partially enlarged sectional view of line BB of A.

[0111] The HUD system of the second embodiment is a HUD system in the HUD system 1 of the first embodiment, in which the laminated glass 10 is replaced with a laminated glass 10B having an interlayer film 13B. Figure 4 A and Figure 4 The difference between the laminated glass 10B shown in Figure B and the laminated glass 10 is that it defines two HUD display areas used in the head-up display.

[0112] HUD region R1 is the region corresponding to HUD region R in the first embodiment, and is provided with a P-polarized light reflective film 15 and a light absorption layer 18. HUD region R2 is positioned closer to the upper side of the laminated glass 10B than HUD region R1 when the laminated glass 10B is installed on the vehicle. HUD region R2 is the region from which unpolarized light is irradiated from a light source different from the light source 50, and no P-polarized light reflective film or light absorption layer is provided in HUD region R2.

[0113] In the laminated glass 10B, at least in the HUD display area R2, the interlayer film 13B has a wedge-shaped cross-section. That is, at least in the HUD display area R2, the interlayer film 13B has a wedge-shaped cross-section with its thickness gradually increasing from the lower side to the upper side of the laminated glass 10B while it is mounted on the vehicle. In this case, if the thickness of the first glass plate 11 and the second glass plate 12 is constant, it is preferable to vary the wedge angle δ of the interlayer film 13B, for example, within a range greater than 0 mrad and less than 1.0 mrad. This reduces the distance between the main image and the ghost image, making them approximately overlap and minimizing the ghost image's prominence.

[0114] Additionally, the wedge angle δ is an angle obtained by dividing the difference in thickness between the upper and lower ends of the HUD display area R2 in the vertical direction when the laminated glass 10B is installed on the vehicle by the distance between the upper and lower ends along the glass shape. The increase in thickness of the laminated glass 10B from the lower end to the upper end can be a monotonically increasing increase with a constant ratio, or the increase ratio can vary locally.

[0115] In addition, Figure 4 A and Figure 4 In the example shown in B, the intermediate film 13B is formed into a cross-sectional lower wedge shape, but it is not limited to this. That is, in the HUD display area R2, at least one of the first glass plate 11, the second glass plate 12, and the intermediate film 13B can have a region with a cross-sectional wedge shape. For example, the thickness of the intermediate film 13B can be kept constant while the first glass plate 11 and / or the second glass plate 12 are formed into a cross-sectional lower wedge shape, and the intermediate film 13B can also be formed into a cross-sectional lower wedge shape. In any of the above cases, it is preferable that the total wedge angle δ is greater than 0 mrad and less than 1.0 mrad. It is more preferable that the total wedge angle δ is more than 0.15 mrad and less than 0.60 mrad. It is more preferable that it is 0.17 mrad or more. In this way, the distance between the main image and the ghost image can be reduced, so that the main image and the ghost image largely overlap, and the ghost image is not noticeable.

[0116] Furthermore, when the first glass plate 11 and the second glass plate 12 are manufactured, for example by float glass, the cross-sectional wedge shape can be formed by adjusting the manufacturing conditions. Specifically, by adjusting the circumferential speed of the multiple rollers arranged at both ends of the glass belt traveling on the molten metal in the width direction, the glass cross-section in the width direction can be made concave, convex, or conical, thus cutting out a portion with arbitrary thickness variation.

[0117] Therefore, the laminated glass 10B has HUD display areas R1 and R2 for irradiating P-polarized light, and at least one of the first glass plate 11, the second glass plate 12, and the interlayer film 13B is wedge-shaped in cross-section in the HUD display area R2. This reduces the distance between the main image and the ghost image, making them approximately overlap and thus minimizing the ghost image's visibility.

[0118] In the laminated glass 10B, for example, the vehicle speed can be displayed continuously in the HUD display area R2, while a warning can be displayed only when needed in the HUD display area R1. However, the display content illustrated here is only one example and is not limited to this.

[0119] <Examples and Comparative Examples>

[0120] The following describes the embodiments and comparative examples, but the present invention is not limited to these examples. In addition, Example 1 is an embodiment, and Examples 2 and 3 are comparative examples.

[0121] [Example 1]

[0122] A first glass plate A (manufactured by AGC Corporation, commonly known as VFL), which becomes the inner panel (inner side glass panel) in the laminated glass manufacturing process, and a second glass plate B (manufactured by AGC Corporation, commonly known as VFL), which becomes the outer panel (outer side glass panel) in the laminated glass manufacturing process, are prepared. Both the first glass plate A and the second glass plate B have dimensions of 300mm × 300mm × 2mm thickness. Additionally, an interlayer film C (manufactured by Sekisui Chemicals Co., Ltd., PVB, 0.76mm thick) is prepared. The first glass plate A, the second glass plate B, and the interlayer film C are not wedge-shaped in cross-section, but rather have a certain thickness.

[0123] Next, a P-polarized light reflective film (a TiZrO2 / SiO2 laminate with a geometric film thickness of 73.9 nm / 99.5 nm) is coated onto all four surfaces of the inner side of the first glass plate A. Meanwhile, a black ceramic layer (inorganic bonding component: black ceramic paste (Bi2O3-SiO2 system), inorganic powder component: MnO2 system, inorganic bonding component: inorganic powder component (weight ratio) 80:20 to 60:40) is formed on the two surfaces of the inner side of the second glass plate B as a light-absorbing layer. Then, an interlayer film C is sandwiched between the first glass plate A coated with the P-polarized light reflective film and the second glass plate B with the black ceramic layer, and the laminate is bonded under vacuum conditions controlled within the range of 100 kPa to -65 kPa and at a temperature controlled within the range of approximately 70°C to 110°C. Then, under controlled conditions of 100℃~150℃ and absolute pressure of 0.6MPa~1.5MPa, a heating and pressurizing process is carried out to produce laminated glass.

[0124] [Example 2]

[0125] Except that the P-polarized light reflective film is not coated on the four surfaces inside the first glass panel A, the laminated glass is made in the same manner as in Example 1.

[0126] [Example 3]

[0127] Except that no black ceramic layer is formed on the two surfaces that become the inner side of the second glass panel B, the laminated glass is made in the same manner as in Example 1.

[0128] [evaluate]

[0129] The laminated glass panels manufactured in Examples 1 to 3 were arranged at a 33-degree angle relative to the horizontal. Then, visible light with P-polarization was incident from a light source at an angle of 57 degrees on all four sides of each laminated glass. After the reflected light from each laminated glass was incident on a filter to remove S-polarization, it was captured by a camera positioned at the center of the field of view based on SAE International Automotive Surface Standard J1757-2 (2018). The brightness and presence of ghosting of the main image in the HUD image captured by the camera were then visually confirmed. Additionally, visible light with P-polarization was incident from a light source at an angle of 67 degrees on all four sides of each laminated glass, and the brightness and presence of ghosting of the main image were confirmed using the same method. The HUD image was a grid-like stripe pattern.

[0130] Table 1

[0131]

[0132] The evaluation results are shown in Table 1. The brightness of the main image is recorded as "suitable" if the grid shape is sufficiently visible, and as "unsuitable" if the grid shape is not sufficiently visible. In addition, the presence or absence of ghosting is recorded as "suitable" if the grid does not appear to be ghosted, and as "unsuitable" if the grid appears to be ghosted.

[0133] As shown in Table 1, the results of Examples 1 and 3 confirm that when visible light of P-polarized light is irradiated onto the laminated glass at an incident angle of 57 degrees, a sufficiently bright primary image is obtained by providing a P-polarized light reflective film on surface 4, and no ghosting occurs. However, when the incident angle is 67 degrees, ghosting can be seen in Example 3.

[0134] This is believed to be because in Example 3, no light-absorbing layer was provided, resulting in an incident angle deviating from the Brewster angle (57 degrees), thus increasing the amount of light reflected from the surface located closer to the outer edge of the vehicle than the P-polarized light reflector. In Example 1, however, a light-absorbing layer was provided, so even if the incident angle deviated from the Brewster angle (57 degrees), the reflection of light from the surface located closer to the outer edge of the vehicle than the P-polarized light reflector was suppressed, thus eliminating the ghosting.

[0135] Furthermore, the results of Example 2 show that even with a light-absorbing layer, if a P-polarized light-reflecting film is not used, the visible light from the P-polarized light source is almost not reflected. Therefore, regardless of the incident angle, the main image will be dark, making it unsuitable as laminated glass for HUD systems. Additionally, because the main image in Example 2 is dark, it is impossible to confirm whether there is ghosting.

[0136] Table 2

[0137]

[0138] The main optical properties of the P-polarized reflective film and light-absorbing layer of the laminated glass prepared in Examples 1 to 3 were confirmed. The confirmation results are shown in Table 2.

[0139] Comparing Example 3 with Examples 1 and 2, it can be seen that if no light absorption layer is provided, the P-polarized light transmittance and S-polarized light transmittance of the P-polarized light reflective film and the light absorption layer reach more than 77% (Example 3), while by providing a light absorption layer, the P-polarized light transmittance and S-polarized light transmittance of the P-polarized light reflective film and the light absorption layer are 0% (Examples 1 and 2).

[0140] Furthermore, comparing Example 3 with Examples 1 and 2, it can be seen that without the light absorption layer, the visible light absorption rate A is as low as 7% or less (Example 3), while with the light absorption layer, the visible light absorption rate A reaches 90% or more, particularly 95% or more (Examples 1 and 2). As described above, by achieving a visible light absorption rate A of 85% or more, reflections on surfaces closer to the outer side of the vehicle than the P-polarized light reflective film can be reduced, thus suppressing ghosting. This condition is clearly evident in Examples 1 and 2.

[0141] Furthermore, comparing Example 2 with Examples 1 and 3, it can be seen that without the P-polarized light reflective film, the P-polarized light reflectivity Rvp at an incident angle of 57 degrees is 0% (Example 2), while by providing the P-polarized light reflective film, the P-polarized light reflectivity Rvp at an incident angle of 57 degrees reaches 10% or more (Examples 1 and 3). As mentioned above, if the P-polarized light reflectivity Rvp at an incident angle of 57 degrees reaches 5% or more, the main image becomes sufficiently bright, and the visibility of the HUD image is improved; this condition is clearly evident in Examples 1 and 3.

[0142] Furthermore, regarding the color hue of P-polarized light at an incident angle of 57 degrees, in any of Examples 1 to 3, the absolute values ​​of a*10 and b*≤10 are satisfied, and in particular, a*≤5 and b*≤5 are satisfied. Regarding the color hue of P-polarized light at an incident angle of 57 degrees, it is believed that problems may arise, for example, when using a color other than a dark color in the light-absorbing layer.

[0143] In summary, as shown in Example 1, by incorporating both a P-polarized light reflective film and a light absorption layer, the visible light absorption rate A can be 85% or higher, and the P-polarized light reflectivity Rvp at an incident angle of 57 degrees can be 5% or higher. Therefore, even when the incident angle deviates from 57 degrees, a sufficiently bright HUD image with suppressed ghosting can be obtained.

[0144] Furthermore, while the examples above only show results for incident angles of 57 degrees and 67 degrees, the inventors confirmed that the laminated glass of Example 1 can produce a HUD image with a sufficiently bright main image and suppressed ghosting even at an incident angle of 72 degrees. In principle, the laminated glass of Example 1 can also produce a HUD image with a sufficiently bright main image and suppressed ghosting even at an incident angle less than 57 degrees.

[0145] The preferred embodiments have been described in detail above, but are not limited to the embodiments described above. Various modifications and substitutions may be made to the embodiments described above without departing from the scope of the claims.

[0146] Furthermore, the entire contents of the specification, claims, drawings, and abstract of Japanese Patent Application No. 2021-085617, filed on May 20, 2021, are hereby cited as a disclosure of this invention.

[0147] Symbol Explanation

[0148] 1HUD system

[0149] 10, 10A, 10B laminated glass

[0150] 11 First Glass Plate

[0151] 12 Second glass plate

[0152] 13, 13B intermediate membrane

[0153] 14 shielding layers

[0154] 14A, 18 light absorption layer

[0155] 15P polarizing reflective film

[0156] 50 light source

[0157] 60 First Optical System

[0158] 70 image display elements

[0159] 80 Second Optical System

[0160] 90° concave mirror.

Claims

1. A laminated glass comprising a first glass plate, a second glass plate, and an interlayer film located between and bonding the first glass plate and the second glass plate. The laminated glass has a portion thereof having a first area for use in a head-up display. When the surface of the first glass plate opposite to the intermediate film is designated as surface 4, the surface of the first glass plate on the side of the intermediate film is designated as surface 3, the surface of the second glass plate on the side of the intermediate film is designated as surface 2, and the surface of the second glass plate opposite to the intermediate film is designated as surface 1, In the first region, a P-polarized light reflective film is disposed on the 4th surface, and a light absorption layer is disposed on the 2nd surface. Let the sum of the visible light transmittance of the P-polarized reflective film and the visible light transmittance of the light absorption layer be Tv%, and let the sum of the visible light reflectance of the P-polarized reflective film and the visible light reflectance of the light absorption layer be Rv%. When the absorption rate A = 100 - Tv - Rv [%), A ≥ 85% is satisfied. When P-polarized light is incident from the P-polarized light reflective film side at an incident angle of 57 degrees, the sum of the P-polarized light reflectivity of the P-polarized light reflective film and the P-polarized light reflectivity of the light absorption layer is set as Rvp%, which satisfies Rvp≥5%.

2. The laminated glass as described in claim 1, wherein, When the color hue of the light reflected by the P-polarized light reflector and the light absorption layer is set as a* and b* when P-polarized light is incident on the P-polarized light reflector at an incident angle of 57 degrees, a*≤10 and b*≤10 are satisfied.

3. The laminated glass as described in claim 1 or 2, wherein, It has a shielding layer arranged in a strip shape along the periphery of the two surfaces. The shielding layer is locally widened to form the light-absorbing layer.

4. The laminated glass as described in claim 1 or 2, wherein, The light-absorbing layer is a colored ceramic layer.

5. The laminated glass as described in claim 1 or 2, wherein, The first glass plate is bent in a manner that bulges toward the intermediate film.

6. The laminated glass as described in claim 1 or 2, wherein, At least one of the first glass plate, the second glass plate, and the interlayer film has a wedge-shaped region with a thickness that gradually increases from the lower side to the upper side of the laminated glass when the laminated glass is mounted on a vehicle.

7. The laminated glass as claimed in claim 6, wherein, The wedge-shaped region of the cross section is included in the second region used in the head-up display.

8. A head-up display system, comprising: The source of visible light that emits P-polarized light, and The laminated glass according to any one of claims 1 to 7, wherein the visible light of the P-polarized light is incident on the P-polarized light reflective film, The head-up display system is a vehicle head-up display system that displays a virtual image on the outside of the laminated glass.

9. The head-up display system as claimed in claim 8, wherein, The incident angle of light from the light source when it is incident on the P-polarized reflective film is greater than 57 degrees.

10. The head-up display system as claimed in claim 8, wherein, The incident angle of light from the light source when it is incident on the P-polarized reflective film is below 47 degrees or above 62 degrees.

Images