Projection image display component and head-up display system

Abstract

The object of the present invention is to provide a projection image display member that can clearly display images in multiple areas, and to provide a head-up display system that uses the projection image display member of the present invention as a screen material. [Solution] A projection image display member comprising a transparent member, a resin layer, and a P-wave reflector, and further having a colored layer in part, wherein two orthogonal lines are drawn on the surface of the projection image display member passing through the center point C of the projection image display member and such that the shorter of the two lines is the shortest length, with the longer line being the x-axis and the shorter line being the y-axis, and the points located 50 mm inward from the end of the projection image display member on the x-axis and y-axis are designated as points x1, x2, y1, and y2, respectively, the thickness of the resin layer increases or decreases in the order of point x1, the center point C, and point x2, or in the order of point y1, the center point C, and point y2.

Description

Technical Field

[0001] The present invention relates to a projection image display member capable of clearly projecting an image onto a plurality of display areas, and a head-up display system equipped with the same.

Background Art

[0002] In recent years, spatial projection technologies such as head-up displays and head-mounted displays that irradiate light onto a transparent member such as glass or a transparent resin material and display an image superimposed on the surrounding scenery have been actively developed. In such a spatial projection technology, a display method is generally used in which light is irradiated onto a transparent member from an oblique direction and reflected, and the reflected image is delivered to the observer's field of view. For example, in the automotive field, an image is projected onto the transparent portion of the front glass arranged at an oblique angle by the light emitted from a light source installed in the dashboard portion, so that the driver can visually recognize the image superimposed on the scenery from the car window at the same time. A head-up display method called a front glass reflection type head-up display (W-HUD) has been put into practical use.

[0003] Light is generally a composite wave composed of two types of polarized light with different vibration directions, called P-wave (P polarization) and S-wave (S polarization). The P-wave is polarized light in which the electric field vibrates in the direction of the light incident plane, and the S-wave is polarized light in which the electric field vibrates perpendicular to the light incident plane. Usually, in a transparent member such as glass, the reflectance of the P-wave decreases as the incident angle increases, and shows a tendency to become minimal at a certain incident angle called the Brewster angle and then increase again. On the other hand, the S-wave shows a tendency that the reflectance increases monotonically as the incident angle increases.

[0004] From these points of view, when projecting an image onto a transparent member by irradiating it with light from an oblique direction, it is common practice to project the image using a light source that emits light mainly containing S-wave components, in order to project the image regardless of the installation configuration of the transparent member (Patent Document 1). However, when projecting an image onto a transparent member by irradiating it with light mainly containing S-wave components, the light is reflected at the interface between the outermost surfaces on both sides of the transparent member and the air, and the image from the reflected light is delivered to the observer's field of view through separate optical paths. As a result, head-up displays of this type have problems such as the image being perceived as a multiple image and the image blacking out when wearing polarized sunglasses.

[0005] To address the problem of multiple images, as shown in Patent Document 1, there is a method of using a wedge-shaped material as an interlayer component constituting the projection image display member, and designing it so that the light of the image reflected from both outermost surfaces of the projection member overlaps with each other, thereby preventing the multiple images from being visible. However, in this method, if the projection image display member is designed so that multiple images are not visible in a specific area, the angle of incidence of the image light will be shifted in other areas of the projection image display member. Even a slight difference in the angle of incidence of less than 1° can reduce the degree of overlap of the images and cause multiple images to appear. Therefore, when using a wedge-shaped material, multiple images cannot be sufficiently suppressed when projecting an image over a wide area onto a projection image display member.

[0006] To address the above issues, a new projection method has been developed and investigated that utilizes a light source with high P-wave purity for projecting images, and incorporates a P-wave reflector (such as a film or coating) that can reflect P-waves even when incident at an oblique angle as part of a transparent component (Patent Document 2). By using a projection image display component in this manner, the light of the image is less likely to be cut off by polarized sunglasses, and furthermore, the effect of multiple image display can be reduced by suppressing light reflection on the surface of the transparent component and reflecting light only at the P-wave reflector portion. In addition, laminated films that utilize interference reflection of light by regularly stacking different thermoplastic resin layers have been used as P-wave reflectors, such as those stretched in the uniaxial direction (Patent Documents 3 and 4) or those sequentially stretched biaxially at approximately equal magnifications in the longitudinal and width directions (Patent Documents 5 and 6).

[0007] Furthermore, in automotive applications, a technology is being considered to project images from a P-wave light source onto a projection display element. This method projects the image not onto the transparent area of ​​the vehicle's windshield, but onto a colored layer of laminated black ceramic located at the bottom of the windshield. This type of system is called a panoramic head-up display (P-HUD), and its development aims to allow drivers to view information such as speed indicators and warning signals, which are normally displayed on the instrument panel, while minimizing eye movement during driving. Since the P-HUD and the W-HUD differ in the information they project, their mechanisms, and their purposes, efforts to incorporate both display methods simultaneously are also being considered. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] International Publication No. 2017 / 170727 [Patent Document 2] Japanese Patent Publication No. 2023-083309 [Patent Document 3] Special Publication No. 2023-512713 [Patent Document 4] Special Publication No. 2023-502234 [Patent Document 5] International Publication No. 2019 / 198635 [Patent Document 6] International Publication No. 2023 / 054117 [Overview of the Initiative] [Problems that the invention aims to solve]

[0009] However, when using a laminated film stretched in a uniaxial direction, as exemplified by Patent Documents 3 and 4, as a P-wave reflector, the reflectance remains above a certain level regardless of the angle of incidence even when the P-wave reflector is tilted in a direction parallel to the orientation axis. Conversely, the reflectance decreases when the P-wave reflector is tilted in a direction different from the orientation axis. Due to this characteristic, projection image display members using such laminated films as P-wave reflectors have low light transmittance in the front direction, and the change in reflectance becomes large when the field of view is changed to an angle different from the orientation axis. Therefore, they have the problem of being unsuitable for video displays that require visibility over a wide field of view, and in particular, they are unsuitable for augmented reality W-HUD (AR-HUD) systems that simultaneously project images with different focal lengths over a wide field of view.

[0010] Furthermore, when using a biaxially stretched laminated film, such as those described in Patent Documents 5 and 6, as a P-wave reflector, the reflectivity of P-waves can be increased as the angle of incidence increases, regardless of the azimuth angle tilted relative to the normal direction of the film surface. This feature allows for strong reflection of the light from the image and clear display of the image when projecting an image onto a projection image display member installed at an oblique angle when viewed from a nearly horizontal plane, such as a vehicle windshield, at a large angle of incidence. Therefore, projection image display members using such laminated films are suitable for use in head-up displays that project images from light incident at an oblique angle while maintaining transparency.

[0011] However, when such laminated films are applied to large projection image display members, under conditions where the light reflectivity of the laminated film is high, such as when the angle of incidence is large, while the image can be displayed clearly, reflections near the dashboard where the light source is installed become stronger, worsening the visibility of the scenery. In other words, in such configurations, there is a trade-off relationship between image projection and scenery visibility, and it is difficult to achieve both. In particular, in the case of the P-HUD method, which projects images onto a part with a colored layer, the angle of incidence of the image from the display tends to be larger relative to the observer's line of sight, in terms of the spatial arrangement of the projection area and the placement of the image projector. As a result, the light reflectivity of the image becomes higher, and combined with the coloring of the background, reflections around the display also become larger. On the other hand, if the vehicle is designed so that the angle of the windshield is steep in order to reduce the angle of incidence and lower the reflectivity of the colored layer, the angle of incidence of light for the image projected simultaneously onto the transparent area becomes smaller. Therefore, problems arise such as the projected image appearing dark, and the deviation from the Brewster angle causing undesirable image reflections on the windshield surface, resulting in the perception of multiple images.

[0012] In other words, with conventional technology, when displaying multiple images at different positions on a large projection image display element such as a vehicle's windshield, specifically when simultaneously using the W-HUD method (AR-HUD method) which projects onto a transparent area and the P-HUD method which projects onto an area with a colored layer, it was difficult to display images from a projector installed on the dashboard clearly without overlapping images, or to reduce appearance defects such as reflections of the outside scenery.

[0013] The present invention aims to solve the above problems by providing a projection image display member that can clearly display images in multiple areas, and by providing a head-up display system that uses the projection image display member of the present invention as a screen material. [Means for solving the problem]

[0014] To solve the above problems, the projection image display member of the present invention has the following configuration. The projection image display member of the present invention comprises a transparent member, a resin layer, and a P-wave reflector, and further has a colored layer in part, wherein two orthogonal lines are drawn on the surface of the projection image display member passing through the center point C of the projection image display member and such that the shorter of the two lines is the shortest, with the longer line being the x-axis and the shorter line being the y-axis, and the points located 50 mm inward from the end of the projection image display member on the x-axis and y-axis are designated as points x1, x2, y1, and y2, respectively, the thickness of the resin layer increases or decreases in the order of point x1, the center point C, and point x2, or in the order of point y1, the center point C, and point y2.

[0015] Furthermore, in another embodiment of the projection image display member of the present invention, the projection image display member comprises a transparent member, a resin layer, and a P-wave reflector, wherein two orthogonal lines are drawn on the surface of the projection image display member, passing through the center point C of the projection image display member, such that the shorter of the two lines is the shortest length, with the longer line being the x-axis and the shorter line being the y-axis, and the points located 50 mm inward from the end of the projection image display member on the x-axis and y-axis are designated as points x1, x2, y1, and y2, respectively, then point x1, the center point C, and the front A projection image display member is provided that satisfies the following conditions (1) to (3) simultaneously, where the thickness of the resin layer increases or decreases in the order of marked points x2, or in the order of point y1, the center point C, and point y2, and when the average transmittance of visible light incident at the center point C at an incident angle of 0° is T(0°), the tangent surface at the center point C is the reflective surface, and the average reflectance at wavelengths of 400 to 700 nm, obtained by incidenting linearly polarized light containing only the P-polarization component along the incident surface including the orientation axis at the center point C at an incident angle θ, is Rp(θ). (1) T(0°)≧70% (2) Rp(60°)≧20% (3) Rp(20°)≦Rp(40°) <Rp(60°)。

[0016] Furthermore, the projected image display member of the present invention can also be in the following forms, and as shown below, it can be used as a screen material to form a head-up display system. [1] A projection image display member comprising a transparent member, a resin layer, and a P-wave reflector, and further having a colored layer in part, wherein two orthogonal lines are drawn on the surface of the projection image display member passing through the center point C of the projection image display member and such that the shorter of the two lines is the shortest, with the longer line being the x-axis and the shorter line being the y-axis, and the points located 50 mm inward from the end of the projection image display member on the x-axis and y-axis are designated as points x1, x2, y1, and y2, respectively, the thickness of the resin layer increases or decreases in the order of point x1, the center point C, and point x2, or in the order of point y1, the center point C, and point y2. [2] The projection image display member according to [1], having a configuration in which a transparent member 1, a resin layer 1, the P-wave reflector, a resin layer 2, and a transparent member 2 are laminated in that order, the colored layer is laminated in a portion between the transparent member 2 and the resin layer 2, and the thickness of the resin layer 1 increases or decreases in the order of point x1, the center point C, and point x2, or in the order of point y1, the center point C, and point y2. [3] The projection image display member according to [1] or [2], wherein the colored layer extends along the x-axis direction and includes point y2. [4] A projection image display member according to any one of [1] to [3], wherein the region provided with the colored layer is defined as the first region, the region not provided with the colored layer is defined as the second region, point y3 is the point on the line connecting point y1 and point y2 that is the boundary between the first region and the second region, and the thicknesses of the resin layer 1 at points y1 to y3 are defined as dy1 to dy3 in order, respectively, satisfying the relationship dy1≧dy3>dy2. [5] The projection image display member according to [4], wherein the distance between the two points y1 and y3 is y1-y3, the distance between the two points y2 and y3 is y3-y2, and the thickness of the projection image display member at points y1 to y3 is Dy1 to Dy3 in order, such that the relationship (Dy1-Dy3) / (y1-y3)>(Dy3-Dy2) / (y3-y2) is observed. [6] Let the average transmittance of visible light incident at an incident angle of 0° on the center point C2 of the second region be T2(0°). Using the tangent plane at the center point C2 as the reflecting surface, when linearly polarized light containing only the P polarization component is incident from the transparent member 2 side at an incident angle θ along the incident plane including the orientation axis at the center point C2, and the average reflectance in the wavelength range of 400 to 700 nm thus obtained is Rp2(θ), the projection image display member according to [4] or [5], which satisfies both T2(0°) ≥ 70% and Rp2(60°) ≥ 20%. [7] Using the tangent plane at the center point C2 of the second region as the reflecting surface, when linearly polarized light containing only the P polarization component is incident from the transparent member 2 side at an incident angle θ along the incident plane including the orientation axis at the center point C2, the average reflectance Rp2(θ) in the wavelength range of 400 to 700 nm satisfies Rp2(20°) ≤ Rp2(40°) < Rp2(60°), and the projection image display member according to any one of [4] to [6]. [8] When linearly polarized light containing only the P polarization component is incident on the center point C2 from the transparent member 2 side at an incident angle of 60° with the tangent plane at the center point C2 of the second region as the reflecting surface, with the direction of the incident plane including the orientation axis being 0°, when the projection image display member is rotated in-plane within a range of 0° to 90° around C2, the amount of change in the average reflectance in the wavelength range of 400 to 700 nm is 0% or more and 25% or less, and the projection image display member according to any one of [4] to [7]. [9] The projection image display member according to any one of [2] to [8], in which the resin layer 2 contains more near-infrared absorbing material than the resin layer 1.

[10] A head-up display system including the projection image display member according to any one of [1] to [9] and a video projector 1 that projects an image by irradiating light with a P polarization component ratio of 51% or more and 100% or less. The P-wave reflector of the projection image display member is located on the light-irradiated surface side of the colored layer. When the region where the colored layer is provided in the projection image display member is defined as the first region, the video projector 1 projects an image onto the first region.

[11] Further, it includes a video projector 2 that projects an image by irradiating light with a P-polarized component ratio of 51% or more and 100% or less. When the region not including the coloring layer in the projection image display member is defined as the second region, the incident angle α (°) of the light incident from the video projector 1 on the first region is larger than the incident angle β (°) of the light incident from the video projector 2 on the second region. The head-up display system according to

[10] .

[12] The head-up display system according to

[10] or

[11] , wherein the incident angle α and the incident angle β satisfy 45° ≤ incident angle β < incident angle α ≤ 75°.

[13] When the center point of the video projection range in the first region is point A, the average transmittance of the visible light region incident at an incident angle of 0° on point A is TA(0°), the tangent plane at point A is used as the reflection surface, and linearly polarized light containing only the P-polarized component is incident at an incident angle θ along the incident plane including the alignment axis at point A. When the average reflectance in the wavelength range of 400 to 700 nm is RpA(θ), the head-up display system according to any one of

[10] to

[12] , which satisfies both TA(0°) ≤ 1% and RpA(α) ≥ 20%.

[14] When the center point of the video projection range in the second region is point B, the angle formed by the intersection line of the plane including the electric field vibration direction of the P-polarized component of the light emitted from the video projector 2 and the projection image display member surface and the alignment axis at point B is 0° or more and 10° or less, or 80° or more and 90° or less. The head-up display system according to any one of

[10] to

[13] .

[15] The head-up display system according to any one of

[10] to

[14] , wherein the video projector 2 has a light source unit that irradiates light of the video inside and a curved mirror, and further includes a polarizing plate at the display exit.

[16] The head-up display system according to any one of

[10] to

[15] , wherein the light emitted from the video projector 1 does not have a peak with a half-value width of 15 nm or less in the wavelength range of 400 to 800 nm, or has one peak.

[17] A projection image display member comprising a transparent member, a resin layer, and a P-wave reflector, wherein two orthogonal lines are drawn on the surface of the projection image display member, passing through the center point C of the projection image display member and such that the shorter of the two lines is the shortest, with the longer line being the x-axis and the shorter line being the y-axis, and the points located 50 mm inward from the end of the projection image display member on the x-axis and y-axis are designated as points x1, x2, y1, and y2, respectively, in the order of point x1, the center point C, and point x2, or A projection image display member that simultaneously satisfies the following (1) to (3), wherein the thickness of the resin layer increases or decreases in the order of point y1, the center point C, and point y2, and the average transmittance of visible light incident at the center point C at an incident angle of 0° is T(0°), the tangent surface at the center point C is the reflective surface, and the average reflectance at wavelengths of 400 to 700 nm, obtained by incidenting linearly polarized light containing only the P-polarization component along the incident surface including the orientation axis at the center point C at an incident angle θ, is Rp(θ). (1) T(0°)≧70% (2) Rp(60°)≧20% (3) Rp(20°)≦Rp(40°) <Rp(60°)

[18] The projection image display member according to

[17] , wherein when linearly polarized light containing only the P-polarized component is incident on the center point C2 at an incident angle of 60°, with the tangent surface at the center point C being the reflective surface, the change in average reflectance at wavelengths of 400 to 700 nm is 0% or more and 25% or less when the projection image display member is rotated in-plane from 0° to 90° around the center point C, with the direction of the incident surface including the orientation axis being 0°. [Effects of the Invention]

[0017] The present invention provides a projection image display member capable of clearly displaying images in multiple areas, and a head-up display system using the projection image display member of the present invention as a screen material. [Brief explanation of the drawing]

[0018] [Figure 1] This is a schematic diagram illustrating the center point C of the projected image display member of the present invention and the measurement points for each thickness. [Figure 2] This is a schematic diagram illustrating a head-up display system according to one embodiment of the present invention. [Figure 3] This is a cross-sectional view in the thickness direction of a projection image display member according to one embodiment of the present invention. [Figure 4] This is a cross-sectional view in the thickness direction of a projection image display member according to one embodiment of the present invention. [Figure 5] This is a cross-sectional view in the thickness direction of a projection image display member according to one embodiment of the present invention. [Figure 6] This is a cross-sectional view in the thickness direction of a projection image display member according to one embodiment of the present invention. [Figure 7] This is a cross-sectional view in the thickness direction of a projection image display member according to one embodiment of the present invention. [Figure 8] This is a schematic diagram illustrating a method for measuring the inclination angle of a resin layer used in a projection image display member of the present invention. [Figure 9] This is a schematic diagram illustrating the measurement results of the inclination angle of the resin layer used in the projection image display member of the present invention. [Figure 10] This is a schematic diagram illustrating the colored layer region of a projection image display member according to one embodiment of the present invention. [Figure 11] This is a schematic diagram illustrating the colored layer region and point y3 of a projection image display member according to one embodiment of the present invention. [Figure 12] This is a schematic diagram illustrating the center point C2 in the second region of the projected image display member of the present invention. [Figure 13] This is a schematic diagram illustrating the reference line C of the projected image display member of the present invention. [Figure 14] This is a schematic diagram illustrating the angle between the reference line C and the orientation axis of the projection image display member of the present invention. [Figure 15] This is a schematic diagram illustrating the relationship between depth in the thickness direction and contrast difference (gray level) in a cross-sectional observation image of a laminated film (having a regular arrangement in which layers are alternately stacked in an arrangement of (AB)n (where n is a natural number representing the number of repeating units)) that can be used in the projection image display member of the present invention. [Figure 16]This is a schematic diagram illustrating the relationship between depth in the thickness direction and contrast difference (gray level) in a cross-sectional observation image of a laminated film (having a regular arrangement in which layers are regularly stacked in an arrangement of (ACBC)n (where n is a natural number representing the number of repeating units)) that can be used in the projection image display member of the present invention. [Figure 17] This is a schematic diagram illustrating the relationship between depth in the thickness direction and contrast difference (gray level) in a cross-sectional observation image of a laminated film (having a regular arrangement in which layers are regularly stacked in an arrangement of (ACBC)n (where n is a natural number representing the number of repeating units)) that can be used in the projection image display member of the present invention. [Figure 18] This is a schematic diagram showing the emission spectrum of the light source of the image projector used in a head-up display system according to one embodiment of the present invention (as used in the example). [Figure 19] This is a schematic diagram showing the emission spectrum of the light source of the image projector used in a head-up display system according to one embodiment of the present invention (as used in the example). [Figure 20] This is a schematic diagram illustrating a head-up display system according to one embodiment of the present invention. [Figure 21] This is a schematic diagram illustrating the image projection area and point A in the first region of the projected image display member, and the image projection area and point B in the second region, in a head-up display system according to one embodiment of the present invention. [Modes for carrying out the invention]

[0019] The projection image display member of the present invention will be described in detail below. As described below, the projection image display member of the present invention includes a first projection image display member and a second projection image display member. Hereinafter, these will be collectively referred to as the projection image display member of the present invention.

[0020] The first projection image display member of the present invention comprises a transparent member, a resin layer, and a P-wave reflector, and further having a colored layer in part, wherein when two orthogonal lines are drawn on the surface of the projection image display member passing through the center point C of the projection image display member and the shorter of the two lines being the shortest, with the longer line being the x-axis and the shorter line being the y-axis, and the points located 50 mm inward from the end of the projection image display member on the x-axis and y-axis are designated as points x1, x2, y1, and y2, respectively, the thickness of the resin layer increases or decreases in the order of point x1, the center point C, and point x2, or in the order of point y1, the center point C, and point y2, the projection image display member is characterized in that,

[0021] The second projection image display member of the present invention is a projection image display member comprising a transparent member, a resin layer, and a P-wave reflector, wherein two orthogonal lines are drawn on the surface of the projection image display member, passing through the center point C of the projection image display member and having the shortest length as the minimum, with the longer line being the x-axis and the shorter line being the y-axis, and the points located 50 mm inward from the end of the projection image display member on the x-axis and y-axis are designated as points x1, x2, y1, and y2, respectively, the thickness of the resin layer increases or decreases in the order of point x1, the center point C, and point x2, or in the order of point y1, the center point C, and point y2. The projection image display member satisfies the following conditions (1) to (3) simultaneously, when T(0°) is the average transmittance of visible light incident at the center point C at an incident angle of 0°, the tangent surface at the center point C is the reflecting surface, and linearly polarized light containing only the P-polarization component is incident along the incident surface including the orientation axis at the center point C at an incident angle θ, and Rp(θ) is the average reflectance at wavelengths of 400 to 700 nm. (1) T(0°)≧70% (2) Rp(60°)≧20% (3) Rp(20°)≦Rp(40°) <Rp(60°)。

[0022] In the present invention, a projected image display member refers to a member that has the function of projecting an image by specularly reflecting light emitted from an image projector. Through the above function, the projected image display member can deliver an image to the field of view of an observer located at a specific position, and the observer can view the image displayed on the projected image display member. The projected image display member of the present invention comprises a transparent member, a resin layer, and a P-wave reflector. Each of these members will be described below.

[0023] Examples of transparent materials constituting the projection image display member of the present invention include glass and transparent resin, and it is preferable to use a material with a thickness of 1 mm or more to provide support. Here, "transparent" means that when the member is viewed from the normal direction, the average transmittance in the visible light region (wavelength 400 to 800 nm) is 50% or more and 100% or less. Whether or not a member is transparent is determined by analyzing the average transmittance in the visible light region (wavelength 400 to 800 nm) under perpendicular incidence, according to the spectral measurement method described in (4) of the measurement method described later. When the transmittance of the projection image display member is measured using the same method, if the average transmittance in the visible light region is 50% or more and 100% or less, the member used in the projection image display member can also be determined to be transparent (if the projection image display member has a colored layer as described later, the above measurement shall be performed in the region other than the colored layer to determine whether or not it is transparent). Furthermore, if the member is not planar, the angle of incidence shall be the angle with its tangent surface (the same treatment shall apply to optical properties hereafter unless otherwise specified).

[0024] There is no particular upper limit to the thickness of the transparent component, but it is preferable that it be 10 mm or less, as excessive thickness of the transparent component would unnecessarily increase the overall weight of the projection image display component. As the glass in the transparent component, not only single-layer glass but also laminated glass using two or more layers, tempered glass, plate glass used as building materials, tempered glass, double-glazed glass, and vacuum glass can be used. Examples of transparent resins used as transparent components include polyethylene terephthalate, polycarbonate, acrylic, polyvinyl chloride, polyethylene, polypropylene, polymethylpentene and its copolymers, and acrylonitrile-butadiene-styrene copolymer. These transparent resins may be used individually or in combination of multiple types.

[0025] In particular, when considering the projection image display member of the present invention for use in a vehicle head-up display system, for example, it is preferable to combine two transparent members, specifically, two transparent members bonded together via an adhesive layer, in order to enhance impact resistance as a vehicle window member. Although examples of materials that can be used as transparent members have already been given, for the transparent member placed on the outside of the vehicle, it is preferable to use glass, which has excellent strength, weather resistance, and abrasion resistance, from the viewpoint of being exposed to the harsh outdoor environment. Furthermore, in order to protect the glass from impact and prevent glass shattering and penetration, it is necessary to combine it with an adhesive that exhibits elasticity in the usage environment. For the transparent member on the inside of the vehicle, both glass and transparent resin can be preferably used.

[0026] In the projection image display member of the present invention, the resin layer, having a certain thickness or more, is responsible for the impact resistance, puncture resistance, and adhesion of the entire projection image display member. Furthermore, as described later, it functions as a layer that adjusts the three-dimensional structure of the projection image display member in order to suppress multiple images in the projected image. When the transparent member is used as a resin, both the resin layer and the transparent member are made of resin material, but they differ in that the transparent member is a hard material with excellent strength, heat resistance, and abrasion resistance, while the resin layer is a flexible material with impact resistance and puncture resistance. To determine flexibility, materials that soften at 90°C are distinguished as the resin layer, and materials that exhibit hardness are distinguished as the transparent member. Specifically, in differential scanning calorimetry (DSC) described later, the glass transition temperature of the resin material is measured, and those showing a softening point temperature of 90°C or higher are judged as the transparent member, and those showing a softening point temperature of less than 90°C are judged as the resin layer.

[0027] To satisfy these characteristics, polyvinyl butyral-based or polyurethane-based materials are preferably used for the resin layer. Furthermore, the resin layer preferably contains ultraviolet absorbers and heat absorbers for the purpose of weather resistance (protection of other components of the projected image display member and the image projector) and improvement of the in-vehicle environment. Examples of ultraviolet absorbers include benzotriazole compounds, benzophenone compounds, triazine compounds, and benzoxazinon compounds. Examples of heat absorbers include heat-shielding particles, as well as phthalocyanine compounds, naphthalocyanine compounds, and anthracianine compounds. Examples of heat-shielding particles include lanthanum-based particles, antimony-based particles, indium-based particles, tin-based particles, and tungsten oxide-based particles. Note that either one or both ultraviolet absorbers and heat absorbers may be used, and the number of components is not particularly limited.

[0028] In particular, some heat-absorbing agents absorb not only near-infrared rays but also a portion of visible light. Due to this characteristic, when light from the image projector passes through the resin layer containing the heat-absorbing agent, it can cause changes in the color tone and a decrease in brightness of the image, which can reduce the visibility of the image. To mitigate such problems when used as a head-up display system for vehicles, in the case where the projected image display member of the present invention has a configuration in which resin layers and transparent members are on both sides with respect to a P-wave reflector (described later), it is preferable that the heat-absorbing agent is largely contained in the resin layer on the side opposite to the side from which the image is projected (corresponding to the outside of the vehicle).

[0029] Specifically, the projection image display member of the present invention, as described below, has a configuration in which a P-wave reflector is sandwiched between two different resin layers, or in other words, a configuration in which transparent member 1, resin layer 1, P-wave reflector, resin layer 2, and transparent member 2 are stacked in that order is preferable. However, it is preferable that the resin layer 2, which is placed on the outside of the vehicle when put into practical use as a head-up display, contains more heat-absorbing material than the resin layer (referred to here as resin layer 1) which is preferably used on the light irradiation side. That is, it is preferable that the projection image display member of the present invention contains more heat-absorbing material in resin layer 2 than in resin layer 1. The difference in the concentration of heat-absorbing material between the resin layers can be achieved by adjusting the amount of heat-absorbing agent added to the resin pellets prepared when manufacturing each resin layer.

[0030] In the projection image display member of the present invention, the thickness of the resin layer is preferably 0.05 mm to 1.5 mm from the viewpoint of providing sufficient puncture resistance and impact resistance. In particular, a thinner resin layer can be used for purposes such as reducing the orange peel appearance caused by the difference in thermal shrinkage behavior between the P-wave reflector (especially stretched film) and the resin layer when manufacturing the projection image display member, and superimposing the main image and ghost image to reduce multiple images (sometimes called double images, ghost images, etc.) caused by secondary reflections during image projection as described later. Specifically, from the viewpoint of suppressing orange peel appearance and multiple images, it is preferable to use a resin layer with a thickness of 0.2 mm or less, and more preferably 0.1 mm or less. When multiple resin layers are used as a projection image display member, using at least one thin resin layer can improve appearance issues. If the resin layer wrinkles during the lamination process of the member before heat processing, it may lead to a poor appearance of the projection image display member after heat processing. Therefore, especially when using a thin resin layer of the aforementioned preferred thickness, it is preferable to process it as a projection image display member in a state where it has been pre-pressed with a P-wave reflector.

[0031] In the projected image display member of the present invention, when two orthogonal lines are drawn on the surface of the projected image display member, passing through the center point C of the projected image display member and with the shorter of the two lines being the shortest, the longer line is designated as the x-axis and the shorter line as the y-axis, and the points located 50 mm inward from the end of the projected image display member on the x-axis and y-axis are designated as points x1, x2, y1, and y2, respectively, the thickness of the resin layer increases or decreases in the order of point x1, center point C, point x2, or point y1, center point C, point y2. Here, "the thickness of the resin layer increases or decreases in the order of point x1, center point C, and point x2" refers to the configuration in which the thickness of the resin layer is greater or smaller in the order of point x1, center point C, and point x2, as well as the configuration in which the thickness of the resin layer at point x1 and center point C is equal and the thickness of the resin layer at point x2 is greater or smaller than that, and the configuration in which the thickness of the resin layer at point x2 and center point C is equal and the thickness of the resin layer at point x1 is greater or smaller than that (the same interpretation applies to "the thickness of the resin layer increases or decreases in the order of point y1, center point C, and point y2"). If there are multiple resin layers in the projected image display member, the projected image display member shall be deemed to satisfy the above requirements if at least one resin layer satisfies the above requirements.

[0032] First, the definitions of the center point C of the projection image display member, as well as the x-axis, y-axis, and points x1, x2, y1, and y2, will be explained using Figure 1. Projection image display members are often made of materials that are quadrilateral in shape when viewed macroscopically. For example, if the projection image display member (reference numeral 1) is quadrilateral in shape when viewed macroscopically, the intersection of the diagonals is defined as the center point C (reference numeral 2) (here, "macroscopically" means that although it is not strictly quadrilateral in shape due to slight indentations in the edges or rounded corners, it can be considered identical to a quadrilateral). If the projection image display member is quadrilateral in shape, the intersection of the diagonals is defined as point C (reference numeral 2), as shown in Figure 1. Furthermore, if the shape is other than quadrilateral, or if it is quadrilateral but curved rather than planar, the position corresponding to the centroid of the shape obtained by laying the projection image display member on its side and projecting it from directly above is defined as the center point C (reference numeral 2).

[0033] Furthermore, when any one side of the macroscopic quadrilateral of the projection image display member is fixed parallel to the horizontal plane (symbol 9), two orthogonal lines are drawn on the surface of the projection image display member, passing through the center point C, as shown in Figure 1, and with the shorter side being the shortest. The longer of these two axes is defined as the x-axis (symbol 3), and the points located 50 mm inward along the x-axis from the intersection with the end of the projection image display member are defined as points x1 (symbol 4) and x2 (symbol 5), respectively (either point x1 or y2 is arbitrary). Furthermore, the shorter axis passing through the center point C and orthogonal to the x-axis is defined as the y-axis (symbol 6), and the points located 50 mm inward along the y-axis from the intersection with the end of the projection image display member are defined as points y1 (symbol 7) and y2 (symbol 8), respectively. Note that in order to take each point in this way, the lengths of both the x-axis and y-axis must exceed 100 mm.

[0034] The two lines in this case are drawn along the surface of the projection image display member. Therefore, if the projection image display member is planar, both lines will be straight and perpendicular to each other. However, if it is a curved surface, the two lines will not strictly be perpendicular. However, if the two lines are perpendicular when projected onto the tangent surface at the center point C, then the two lines can be considered perpendicular.

[0035] In the projection image display member of the present invention, based on the above definition, it is necessary that the thickness of the resin layer increases or decreases in the order of point x1, center point C, point x2, or in the order of point y1, center point C, point y2. In a projection image display member where the thickness of the resin layer does not satisfy the above requirement, unless the light constituting the image consists of P-waves with a purity close to 100%, and the angle of incidence of the light from the image projector is set to a special angle that does not reflect P-waves (generally called the Brewster angle), reflection will occur not only at the P-wave reflector but also at multiple interfaces such as the interface between the transparent member and the air. For example, if all of these interfaces are parallel to each other, the light of the image reflected at the multiple interfaces of the projection image display member will be reflected through spatially different optical paths. Therefore, from the perspective of a person viewing the image, multiple reflected images will be seen as a superimposed image. In particular, when using a laminated film suitably used in the projection image display member of the present invention as the P-wave reflector described later, it is difficult to place the transparent member and the P-wave reflector adjacent to each other, so they will be combined via an adhesive member such as a resin layer. In that case, due to the thickness of the resin layer, as well as the thickness of the transparent material and the P-wave reflector itself, the multiple interfaces on which the image is reflected will be located at spatially separated positions. As a result, the optical paths of the multiple reflected images will be separated, making them more easily perceived as multiple images.

[0036] As a method for suppressing these multiple images, in the projection image display member of the present invention, it is effective to make the thickness of the resin layer slope in a specific direction across the entire projection image display member. In particular, when the projection image display member of the present invention is used in applications such as head-up displays, it is preferable to project an image over a wide area of ​​the member. For example, in the case of a projection image display member with a large area such as a windshield for an automobile, it is extremely difficult to project the P-wave component under Brewster angle conditions to the line of sight of a specific person viewing the image over a wide display area and display it without multiple images. Therefore, it is effective to use a method that prevents the generation of multiple images by incident light of the image under Brewster angle conditions in a specific display area, while in other display areas where the incident angle of the light of the image deviates from the Brewster angle, spatially arrange the images from light reflected at multiple interfaces to be close together so that they do not appear as multiple images.

[0037] A preferred configuration for achieving the reduction of multiple images through the above mechanism is to use a material with a gradient in thickness as the resin layer. By adopting this configuration, the optical path of reflected light from each position on the projected image display member can be finely adjusted by designing the difference in thickness and gradient angle of the resin layer, making it possible to bring the reflected image closer three-dimensionally at the observer's eye level. The gradient in thickness for bringing the image closer should be adjusted appropriately according to the actual positional relationship between the projected image display member and the image projector, but the projected image display member is required to have a gradient in thickness in at least one of the x-axis or y-axis directions. From this, it is necessary that the thickness of the resin layer increases or decreases in the order of point x1, center point C, point x2, or in the order of point y1, center point C, point y2. Hereafter, for simplicity, the thickness gradient of the resin layer of the projected image display member will be described as decreasing in the order of point y1, point C, point y2. By adopting this configuration, in a head-up display system with the configuration shown in Figure 2, where the image projector is located on the dashboard below the projected image display member, it becomes possible to design the system to display images superimposed from multiple interfaces, as seen from the driver's perspective.

[0038] When a projection image display member has multiple resin layers, as illustrated in Figures 3 to 6, only one resin layer may satisfy the above thickness relationship, or multiple resin layers may simultaneously satisfy the above thickness relationship, as illustrated in Figure 7. As an example of a projection image display member in which only one of the multiple resin layers exhibits a gradient thickness structure, a resin layer with a triangular cross-section parallel to the thickness direction (hereinafter simply referred to as the cross-section) as shown in Figure 3, a so-called wedge-shaped layer with a trapezoidal cross-section as shown in Figure 4, or a pentagonal cross-section as shown in Figures 5 and 6 may be used.

[0039] In other words, as long as the requirement that "the thickness of the resin layer increases or decreases in the order of point x1, center point C, point x2 (or point y1, center point C, point y2)" is met, it is possible to show a complex thickness profile in which the thickness gradient angle from one end to the other takes various values ​​linearly or nonlinearly (in other words, depending on the position along the axis). Of course, even if it is nonlinear, it is necessary that the overall change is that the thickness increases or decreases from one end to the other. Also, as shown in Figure 7, when multiple resin layers simultaneously show a gradient thickness structure, the gradients of each resin layer may be the same angle, or they may have different angles. In Figures 3 to 7, among the projection image display members, reference numeral 13 denotes the transparent member 1, reference numeral 14 denotes the resin layer 1, reference numeral 15 denotes the P-wave reflector, reference numeral 16 denotes the resin layer 2, reference numeral 17 denotes the transparent member 2, reference numeral 18 denotes the colored layer (details will be described later), reference numeral 19 denotes the first region (details will be described later), and reference numeral 20 denotes the second region (details will be described later).

[0040] The preferred inclination angle in the thickness direction of the resin layer for suppressing multiple images should be selected in accordance with the ECE R43 standard in order to calculate the local correction inclination angle corresponding to the angle of the multiple images. This is calculated based on the average angle of incidence to the projection area and the average radius of curvature of the projection image display member, depending on the configuration of the projection image display member and the angle of incidence of the image onto the projection image display member. In a projection image display member that includes a projection area where an image is displayed by light with an incidence angle near the Brewster angle, such as the projection image display member of the present invention, the inclination angle θ of the resin layer that can be selected to suppress multiple images under the incidence angle conditions to other areas is preferably 0.1 mrad to 2 mrad, more preferably 0.1 mrad to 0.7 mrad. When the cross-sectional shape of the resin layer is wedge-shaped as shown in Figure 8, the inclination angle θ of the resin layer is the interior angle at the intersection of the straight line (reference numeral 21) connecting the first surface portion between the maximum thickness portion and the minimum thickness portion and the straight line (reference numeral 22) connecting the second surface portion. Furthermore, if the cross-sectional shape exhibits a wedge shape with two distinct angles, the angle of inclination is calculated by taking the angle formed by the two lines at the intersection of lines extended from the surface portion for each region with a different inclination. The inclination angle of the resin layer can be measured by measuring the thickness at 5 mm intervals from 0 to 500 mm along the x or y axis (indicated by symbols 3 and 6) of a P-wave reflector or a projection image display member combining resin layers using Lumetrics' "Optigauge" multilayer film thickness measuring instrument, and then calculating the wedge angle.

[0041] For example, in the case of a resin layer having two inclination angles, such as the one used in Figure 6 or Figure 7, measurement results for the measurement position and inclination angle can be obtained as shown in Figure 9. Such a resin layer with an inclination angle can be formed by melt-extruding a resin such as polyvinyl butyrate and using a slot nozzle with an appropriate inclination in the die profile when it is formed into a sheet, by setting an appropriate temperature profile to create an inclination in the resin flow rate, or by selectively stretching it with a stretcher that has an appropriate temperature profile. These methods may be used in combination as appropriate. Reference numerals 23 and 24 in Figure 9 indicate the first inclination angle and the second inclination angle, respectively.

[0042] It is important that the first projection image display member of the present invention has a colored layer in a portion of it. This colored layer can serve as an area onto which an image is projected. For example, when applying the projection image display member of the present invention to an application where it is necessary to project an image onto a transparent material such as the windshield of an automobile, the visibility of the image in the transparent area changes greatly depending on the brightness of the external environment. On the other hand, information such as speed indications and danger signals must always be clearly visible to the driver when they glance at the vehicle while driving. Therefore, in order to ensure that the image is clearly visible regardless of the external environment, it is necessary to provide an area with a colored layer that blocks light from the external environment (outside the vehicle), and to project images such as speed indications and danger signals onto that area. Here, "having a colored layer in a portion of it" means that a portion of the projection image display member has a colored layer, and that is, a projection image display member having a colored layer in a portion of it will have a transparent portion and a colored portion. The projection image display member typically has a colored layer around it to protect the adhesive used to bond the projection image display member to the vehicle housing. However, such a colored layer around the periphery is not considered to be the colored layer corresponding to the area on which the image is projected, as described in this invention.

[0043] In the first projection image display member of the present invention, the colored layer refers to a layer exhibiting a light shielding function, and is defined as a layer exhibiting an average transmittance of 5% or less in the wavelength band of 400 nm to 800 nm (visible light region) of light incident from the normal direction. If it is difficult to isolate each layer from the projection image display member, the projection image display member shall be considered to have a colored layer if there is a location where the above average transmittance is 5% or less. Furthermore, if the projection image display member is curved rather than planar, the angle of incidence shall be the angle made with the tangent surface.

[0044] In vehicle applications where the first projection image display member of the present invention can be suitably used, the colored layer also serves to protect adhesives such as urethane used to fix the window member to the vehicle from the external environment (such as ultraviolet rays and heat rays), and to assist in heat conduction to the outside of the vehicle when a heating means is provided. The higher the light shielding function of the colored layer (in other words, the lower the average transmittance of the colored layer in the visible light region), the greater the durability of the adhesive. Furthermore, when an image is projected onto the colored layer portion required for the first projection image display member of the present invention, the image can be viewed with sufficient brightness even with a small amount of light from the image projector. From the above viewpoint, it is more preferable that the average transmittance is 3% or less, and more preferably 1% or less (theoretically, the lower limit of the average transmittance is 0%, which means a state in which no visible light is transmitted at all).

[0045] The colored layer can be formed using known colored pigments, but a colored pigment-based ceramic layer is particularly suitable. More specifically, a colored ceramic layer is preferred, which is formed by adding heat-resistant colored pigment powder together with low-melting-point glass powder to a resin and solvent, mixing the resulting ceramic paste, applying it to desired areas of a transparent component by printing or other means, and then heating and firing it. One type of colored pigment may be used, or a combination of multiple types may be used, and the thickness of the coating can also be adjusted as appropriate. For example, if you want to increase light shielding, it is preferable to adjust the combination of pigments to approach black or to increase the thickness of the coating.

[0046] The colored layer may be composed of a continuous, integrated film, or it may have a partially formed fine dot pattern. The shape of the dots is not limited to circles, but can also be elliptical, rectangular, polygonal, star-shaped, etc. The dots can also be made transparent, and the other parts can be a dot pattern made of black ceramic layer. Furthermore, the dots can be formed with appropriately varied spacing and size within the colored layer region. The thickness of the colored layer is not particularly limited as long as it does not cause problems with visibility or the practicality of the projected image display component (such as mounting on a vehicle), but for example, when using a black ceramic layer, a thickness of 8 to 20 μm is preferable. When the colored layer is provided with a partially formed fine dot pattern or dot pattern as described above, the thickness should be measured in the colored portion. The area in which the colored layer is provided can be appropriately selected according to the area in which the image is projected.

[0047] Furthermore, if a colored layer is not provided on a portion of the projection image display member, unless the P-wave projecting the image is incident at or near the Brewster angle, the interface between the transparent member and the air, and the multiple interfaces of the P-wave reflector, will function as light reflecting surfaces, making it difficult to suppress multiple images. Specifically, due to the effect of the resin layer exhibiting the gradient thickness described above, it is possible to superimpose the image produced by the light reflected by the transparent member and the image produced by the light reflected by the P-wave reflector, or, in the case of multiple transparent members, the image produced by the light reflected by each transparent member. However, since the optical paths for the reflected images are different, it is difficult to uniquely design the thickness of the resin layer to obtain both effects simultaneously. Therefore, in order to limit the number of interfaces that reflect the light of the image, it is important to provide a colored layer in the first projection image display member of the present invention.

[0048] In the projection image display member of the present invention, a P-wave reflector is a material that exhibits an average reflectance of 5% to 100% in the wavelength range of 400 nm to 700 nm when P-polarized light is incident at an incident angle of 60° with the normal direction as the reference (0°). If the projection image display member is not planar but curved, the incident angle is the angle with the tangent surface. As the P-wave reflector used in the projection image display member of the present invention, it can be appropriately selected from, for example, a coating film containing inorganic particles exhibiting a high refractive index, a multilayer coating film that exhibits light reflection performance by laminating multiple layers of inorganic materials with different refractive indices and a metal layer, or a resin laminate (such as a laminated film) that exhibits light reflection performance by regularly laminating thermoplastic resins with different refractive indices in the direction perpendicular to the surface.

[0049] Whether or not such light reflection characteristics are present can be determined from the reflection spectrum data obtained by measuring the reflectance when P-waves are irradiated at an incident angle θ using a spectrophotometer, with sampling pitches of 1 nm (detailed measurement methods for the reflection spectrum will be described later). If it is difficult to extract the P-wave reflector from the projection image display member, the presence of a P-wave reflector can be determined by whether there are areas in the projection image display member where the average reflectance in the wavelength range of 400 nm to 700 nm (visible light region) is between 5% and 100% when the above measurement is performed at an incident angle of 60°. Alternatively, the optical properties of the P-wave reflector can be determined by the above average reflectance. This is because measuring under the Brewster angle condition of an incident angle of 60° allows us to ignore the influence of light reflection at light reflection interfaces included in the components constituting the projection image display member other than the P-wave reflector.

[0050] Specifically, a coating film containing inorganic particles exhibiting a high refractive index can be a combination of a λ / 2 phase difference film capable of converting P-waves and S-waves and high refractive index particles, in particular, a component having a structure in which an intermediate layer containing high refractive index particles is sandwiched between λ / 2 phase difference films. By using such a P-wave reflector as a projection image display component, when an image with high P-polarization purity is used as the image of the image projector, a clear reflected image obtained based on the S-polarization reflection characteristics of the high refractive index particle layer can be projected, and at other interfaces, the image can not be reflected due to low reflection under the Brewster angle conditions caused by P-polarization. Therefore, the projection image display component can display images clearly without multiple images.

[0051] As the λ / 2 phase difference film, for example, a λ / 2 wave plate made of a stretched film of thermoplastic resin or liquid crystal can be used, such as a phase difference film with a phase difference of 240 nm to 320 nm at a wavelength of 560 nm. Furthermore, as high refractive index particles used in the high refractive index particle layer, examples include TiO2, ZrO2, CeO2, Al2O3, BaTiO3, Nb2O5, and SnO2, and it is preferable to use particles with a primary particle size of 3 nm to 100 nm, either individually or in combination. This high refractive index particle layer may be laminated by sputtering, or it may be provided as an adhesive layer between two λ / 2 phase difference films by mixing a solution dispersed in various organic solvents with an adhesive. A film containing such particles can exhibit a refractive index of about 1.8 to 2.5.

[0052] A multilayer coating film that exhibits light reflection performance by laminating multiple inorganic material layers or metal layers with different refractive indices, which can be used as a P-wave reflector, can be formed, for example, by laminating multiple metal layers and multiple dielectric layers on a projection image display member directly or via a substrate film in a specific thickness configuration. The enhanced reflectivity of the multilayer coating film obtained in this way allows for the reflection of light in the visible light region. Here, a metal layer refers to a layer that exhibits reflectivity characteristics on the film surface and uses more than 50% by mass and less than 100% by mass of a metal inorganic component, and a dielectric layer refers to a layer that controls reflectivity and transmittance by interference of light reflected from multiple film surfaces and uses more than 50% by mass and less than 100% by mass of a dielectric such as an inorganic oxide, fluoride, or nitride, which is not a single metal.

[0053] Metal layers that can be used in multilayer coating films include silver, gold, copper, aluminum, chromium, titanium, zirconium, palladium, osmium, iridium, rhodium, and ruthenium. Alloys combining these materials can also be used. Materials that can be used for the dielectric layer include oxides and nitrides, oxynitrides, and fluorides of Zn, Sn, Ti, Ni, Al, Mg, Sb, Si, Cr, Zr, In, Y, and Ga, which can be used individually or in combination. More specifically, ZnO, AlN, SnO2, TiO2, and NiCrO x ( x is a natural number representing the valence, and the same applies below. ), ZnSnMgO x ZnSnO x , Si3N4, SiO x These can be selected. By selecting these materials and adjusting the thickness of the layers formed from these materials, the multilayer coating film will have suitable P-wave reflection performance for use as a P-wave reflector in the projection image display member of the present invention.

[0054] Such multilayer coating films can be formed on the outermost surface of the projection image display component using known film formation methods such as sputtering, vacuum deposition, and coating. Sputtering methods that can be used include magnetron sputtering, pulsed sputtering, AC sputtering, and digital sputtering. Magnetron sputtering, in particular, is suitable for multilayer coatings because it facilitates the continuous formation of oxide and nitride layers used as dielectrics.

[0055] However, these multilayer coating film configurations have drawbacks, such as the need for high processing precision, the large number of processing steps involved, and the high cost when processing large-area components such as automotive windshields. For this reason, a laminated film in which thermoplastic resins, which will be described in detail later, are laminated in a certain regular arrangement is preferred as the P-wave reflector used in the projection image display member of the present invention.

[0056] The first projection image display member of the present invention consists of a combination of the transparent member, resin layer, P-wave reflector, and a colored layer provided in part of it. More specifically, as an example of a configuration in which the P-wave reflector is located inside the projection image display member, the order is transparent member 1, resin layer 1, P-wave reflector, resin layer 2, transparent member 2, as illustrated in Figures 3 to 7, and the colored layer is provided in part of any interface other than the outermost layer. Here, "a configuration in which transparent member 1, resin layer 1, P-wave reflector, resin layer 2, and transparent member 2 are stacked in order" means that each member is arranged in this order, regardless of whether other layers exist between each layer (member).

[0057] Furthermore, in the first projection image display member of the present invention, in the above configuration, it is preferable that a colored layer is laminated on a portion between the transparent member 2 and the resin layer 2, and that the thickness of the resin layer 1 increases or decreases in the order of point x1, center point C, point x2, or in the order of point y1, center point C, point y2. That is, it is preferable to have a colored layer at the interface with the resin layer 2 located behind the resin layer 1 which has a thickness gradient that has the effect of reducing double images.

[0058] When projecting an image by irradiating the colored layer portion of the first projection image display member of the present invention with light mainly composed of P-polarized light, if the colored layer is present at the interface between the transparent member 2 and the resin layer 2, the colored layer does not act as a barrier to the light of the image from the transparent member 1 side reaching the P-wave reflector, and the gradient thickness structure of the resin layer 1 can also be expected to reduce the appearance of multiple images. Therefore, in the first projection image display member of the present invention, it is preferable that the colored layer is arranged between the transparent member 2 and the resin layer 2 so that the image incident from the resin layer 1 side exhibiting a gradient thickness is not visible as multiple images, even under incident angle conditions where it is reflected by both the transparent member and the P-wave reflector.

[0059] For example, in a vehicle head-up display system in which the first projection image display member of the present invention is positioned such that a region without a colored layer exists above a region containing a colored layer, the region without a colored layer displays images or information with depth superimposed on the scenery. In this case, an augmented reality display combining a concave mirror as an image projector is preferably used to adjust the focal length to an appropriate range according to the scenery outside the car window. When such a display is used, the process of expanding the image with a concave mirror is included, so the angle of incidence from the image projector to the projection image display member varies depending on the projection location. In order to prevent the generation of multiple images, it is preferable to strictly control the angle of incidence from the image projector to the projection image display device according to the installation orientation, angle, and projection location, and to position it particularly close to the Brewster angle.

[0060] On the other hand, for the region with a colored layer located at the bottom of the projected image display device, the projector is usually positioned on the dashboard of the car in such a head-up display system. Therefore, spatially, the angle of incidence of the image is generally 3 to 12° greater than that of the transparent display area without the colored layer. As a result, the angle of incidence of light from the projector deviates from the Brewster angle, making multiple images more likely to be visible. However, because of the presence of the colored layer, the image reflected at the interface between the outermost surface of the projected image display member on the outside of the car and the air after light has passed through the P-wave reflector is not visible. Therefore, by using a gradient thickness of the resin layer to bring the image reflected by the P-wave reflector and the image reflected by the transparent outermost surface of the projected image display member closer together, it is possible to suppress the generation of multiple images.

[0061] Based on the above, the first projection image display member of the present invention can be, for example, in the form shown in Figures 3 to 7. Figures 3 to 7 are all cross-sectional views in the thickness direction of a projection image display member according to one embodiment of the present invention, and the cross-section in the thickness direction refers to the cross-section obtained when cut by a plane perpendicular to the surface of the projection image display member. In Figures 3 to 7, reference numeral 13 denotes the transparent member 1, reference numeral 14 denotes the resin layer 1, reference numeral 15 denotes the P-wave reflector, reference numeral 16 denotes the resin layer 2, reference numeral 17 denotes the transparent member 2, reference numeral 18 denotes the colored layer, reference numeral 19 denotes the first region, and reference numeral 20 denotes the second region.

[0062] The first projection image display member of the present invention may have two transparent members positioned on the outermost surface, and if only the resin layer 1 has a gradient thickness, it may have a constant inclination angle with respect to the entire vertical direction of the projection image display member, as shown in Figures 3 and 4, or it may have different inclinations in the first and second regions, as shown in Figures 5 and 6. Furthermore, if both resin layer 1 and resin layer 2 exhibit a gradient thickness, a configuration like that shown in Figure 7 can be adopted. In this case, each resin layer may have a structure with two different inclination angles depending on the desired inclination angle for suppressing multiple images. These configurations offer advantages in terms of the number and difficulty of the joining member processing process, cost, and even the durability of the P-wave reflector.

[0063] The first projection image display member of the present invention preferably has a colored layer that extends along the x-axis direction and includes a region containing point y2 (the first projection image display member of the present invention will be described below, but if the second projection image display member of the present invention includes a colored layer, a similar configuration can be used). Here, "extending along the x-axis direction and including point y2" means that when a straight line parallel to the x-axis is drawn including point y2, 20% to 100% of that line is covered, and the length on the x-axis side is 1 to 20 times the length on the y-axis side. In a head-up display configured with projected image display members arranged such that the thickness of the resin layer decreases in the order of points y1, C, and y2, with point y2 facing downwards, when an image is delivered from a projector mounted on the dashboard to the driver's line of sight, in order to suppress multiple images using the gradient thickness structure of the resin layer, the display from the projector must be projected below the projected image display member (in other words, it is not possible to create a light path that reflects the image from the projector on the dashboard above the projected image display member to reach the observer's (driver's) eyes). For this reason, it is preferable that the colored layer for displaying the image extends horizontally (in the x-axis direction) below the projected image display member so as not to unnecessarily obstruct the driver's view of the scenery.

[0064] While such a first region (region with a colored layer, reference numeral 19) can be partially provided only in the area directly in front of the driver, as shown in Figure 10, it is preferable to project the image onto a wide, horizontally extending first region, as shown in Figure 11, in order to make it easier to visually display hazard information, especially information about approaching vehicles from the left and right. Furthermore, by providing such a horizontally extending first region, information normally displayed on the center information display can also be projected simultaneously, eliminating unnecessary displays and creating a spacious and orderly interior space, which can also be expected to improve in-vehicle infotainment. For this reason, it is preferable that the colored layer region on which the image is projected extends along the x-axis so as to cover the entire x-axis direction.

[0065] Furthermore, in order to clearly display information such as speed in the area, it is preferable to make the width of the colored layer area (first area) in the y-axis direction wide enough so as not to impair the driver's visibility of the scenery from the car window. In the projected image display member of the present invention, it is preferable that the projection area extends in the x-axis direction so as to include point y2 located 50 mm below the projected image display member. The first area is more preferably provided with a width of 150 mm or more from below the projected image display member, and even more preferably with a width of 200 mm or more. If the width is too wide, the driver will not be able to see information at their feet just in front of the vehicle from their perspective, leading to a decrease in safety. Therefore, it is preferable that the width of the colored layer provided on the projected image display member be 400 mm or less.

[0066] In the first projection image display member of the present invention, the region where a colored layer is provided is designated as the first region, and the region where the colored layer is not provided is designated as the second region. Point y3 is the point on the line connecting points y1 and y2 that corresponds to the boundary between the first region and the second region, and the thicknesses of the resin layer 1 at points y1 to y3 are denoted as dy1 to dy3, respectively. Preferably, the relationship dy1≧dy3>dy2 is satisfied. In the first projection image display member of the present invention, as shown in Figure 11, point y3 is defined as the point where the boundary line between the first region (reference numeral 19) where the colored layer is provided and the second region (reference numeral 20) where the colored layer is provided intersects on the y-axis (reference numeral 6) of the aforementioned projection image display member. Furthermore, the "line connecting points y1 and y2" is drawn along the surface regardless of the surface shape of the projection image display member.

[0067] As mentioned above, it is difficult from a design standpoint to project images onto multiple regions that differ near the Brewster angle across the entire projection image display member from an image projector installed on the dashboard. Therefore, in order to display both the first region containing the colored layer and the second region not containing the colored layer without overlapping images, the incident angle of the image in the first region containing the colored layer is not designed to be near the Brewster angle, and in the second region the incident angle is designed to be near the Brewster angle. Preferably, the resin layer thickness is designed to be sloped so that the image reflected by the transparent member of the projection image display member in the second region and the main image reflected by the P-wave reflector are superimposed.

[0068] In this case, in the second region, if the interfaces of each image reflection are parallel, the incident angle condition will be near the Brewster angle at any interface, so the image of only the P-wave reflector can be clearly seen. On the other hand, if it does not perfectly match the Brewster angle, it is also preferable to apply a resin layer with an even larger inclination angle than the inclination angle set for the first region to the second region, with the aim of suppressing multiple images by superimposing them with images slightly generated at interfaces other than the P-wave reflector.

[0069] From the viewpoint of displaying images with fewer overlapping images in two regions, it is preferable that the thickness of the resin layer 1 satisfies the relationship dy1≧dy3>dy2. The gradient thickness of the resin layer 1 can be formed, as described above, by designing the die profile during sheet formation to have gaps that show an appropriate gradient, by providing a temperature profile that changes continuously in the width direction of the die lip to change the fluidity of the resin and create a gradient in the resin flow rate, or by selectively stretching it with a stretcher that has an appropriate temperature profile (these methods can be used in combination as appropriate).

[0070] Furthermore, as mentioned above, if an image projector that emits light with a large amount of P-polarization component, which can be suitably used in a head-up display using the projected image display member of the present invention, is used, the range of incident angles in which multiple images can be displayed without overlapping images becomes wider compared to conventional projection methods using S-polarization. Therefore, even if the incident angle of the image projected into the second region is designed to be near the Brewster angle, and the incident angle of the image projected into the first region is slightly different from the Brewster angle, the effect of multiple images becomes less noticeable. However, in this case, unwanted reflected images (ghost images) that are different from the main reflected image cannot be completely suppressed, so in order to clearly display only the main reflected image, it is preferable that the resin layer 1 shows a gradient thickness so that the interfaces of the projected image display member each show a different angle design, and in this case, it is preferable that dy1 > dy3.

[0071] The first projection image display member of the present invention preferably exhibits the relationship (Dy1-Dy3) / (y1-y3)>(Dy3-Dy2) / (y3-y2) when the distance between two points y1 and y3 is y1-y3, the distance between two points y2 and y3 is y3-y2, and the thickness of the projection image display member at points y1 to y3 is Dy1 to Dy3 in order. The distance between two points refers to the length between two points along the surface of the projection image display member. (Dy1-Dy3) / (y1-y3) represents the inclination of the entire projection image display member in the second region located in the projection area between points y1 and y3, and (Dy3-Dy2) / (y3-y2) represents the inclination of the entire projection image display member in the first region located in the projection area between points y3 and y2.

[0072] The projection image display member that satisfies this thickness relationship corresponds to the configurations shown in Figures 6 and 7. The fact that the inclination of the projection image display member in the second region is greater than that of the projection image display member in the first region indicates that a large inclination is provided across the entire projection image display member in the second region where no colored layer is provided, which is effective in suppressing multiple images. In the first region, the design is solely aimed at superimposing the image of the image reflected from the surface of the transparent member 1 located on the resin layer 1 side and the image of the image reflected by the P-wave reflector, whereas in the second region, superimposition of images reflected at interfaces that are spatially further apart than in the first region is required. Therefore, if the design satisfies this condition, it may be possible to suppress multiple images not only by superimposing images reflected by the P-wave reflector and each transparent member, but also by superimposing images reflected by the spatially furthest transparent member 1 and transparent member 2. The tilt angle conditions for such a projected image display member can be achieved by applying a resin layer 1 with two different tilt angles with point y3 as the boundary, or by applying a resin layer 2 with a constant tilt angle in a second region in addition to a resin layer 1 that shows a constant angle, thereby changing the tilt angle in a complex manner.

[0073] In the first projection image display member of the present invention, it is preferable that T2(0°) ≥ 70% and Rp2(60°) ≥ 20% when, at the center point C2 of the second region, the average transmittance of visible light incident at an incident angle of 0° to the center point C2 of the second region is defined as T2(0°), the tangent surface at the center point C2 is defined as the reflective surface, and linearly polarized light containing only P-polarization components is incident from the transparent member 2 side at an incident angle θ along the incident surface including the orientation axis at the center point C2, and the average reflectance at a wavelength of 400 to 700 nm is defined as Rp2(θ).

[0074] The method for determining point C2 and the reference axis C of the projected image display member will be specifically explained using Figures 12 and 13. Figure 12 shows one embodiment of the projected image display member of the present invention. In Figures 12 and 13, reference numeral 19 denotes the first region, reference numeral 20 denotes the second region, reference numeral 26 denotes C2, reference numeral 1 denotes the projected image display member, reference numeral 9 denotes the horizontal plane, reference numeral 27 denotes the reference axis C, and reference numeral 28 denotes the tangent surface at C2.

[0075] The second region 20, which corresponds to the transparent area of ​​the projection image display member (reference numeral 1), is often quadrilateral in shape when viewed macroscopically. For example, if the second region (reference numeral 20) is quadrilateral in shape when viewed macroscopically, the intersection of the diagonals is defined as the center point C2 (reference numeral 26) (here, "when viewed macroscopically" means that although it is not strictly quadrilateral due to slight indentations on the edges or rounded corners, it can be considered identical to a quadrilateral). Furthermore, if the shape is other than quadrilateral, or if it is quadrilateral but curved rather than planar, the projection image display member is laid flat, and the position corresponding to the centroid of the shape obtained from the projection view of the second region (reference numeral 20) from directly above is defined as C2 (reference numeral 26). Then, as shown in Figure 13, the line of intersection between the tangent surface (reference numeral 28) and the horizontal plane (reference numeral 9) at C2 becomes the reference line C (reference numeral 27).

[0076] The first projection image display member of the present invention preferably exhibits a T2(0°) ≥ 70% when the contact surface at C2 is a reflective surface and T2(0°) is the average transmittance of visible light incident on C2 at an incident angle of 0° (perpendicularly). Visible light as used herein refers to light in the wavelength band of 400 nm to 800 nm. Because the average transmittance of visible light incident on C2 at an incident angle of 0° is high in this way, the projection image display member as a whole has transparency similar to that of transparent glass or a transparent resin plate, resulting in good visibility when viewing a landscape through the projection image display member.

[0077] From the above viewpoint, T2(0°) is preferably 80% or more, and more preferably 90% or more. If the average transmittance is 90% or more, the observer can view the scenery without noticing the presence of the projected image display member. From the viewpoint of ease of implementation, the upper limit of the average transmittance is preferably 99%. The average transmittance can be measured by measuring the transmittance of light with wavelengths of 400 to 800 nm at an incident angle of 0° in 1 nm increments using a spectrophotometer and calculating the average value (details will be described later).

[0078] One method for increasing the average transmittance of visible light incident at an incident angle of 0° is to use a laminated film, described later, as the P-wave reflector of the projected image display member. In particular, this can be achieved by reducing the difference in refractive index between the thermoplastic resin layer with the highest refractive index (difference in in-plane average refractive index) and the thermoplastic resin layer with the lowest refractive index in the direction parallel to the film surface, among the multiple thermoplastic resin layers constituting the unit consisting of a regularly arranged laminated film. If the unit has an alternating laminated structure, this corresponds to the difference in in-plane refractive index between adjacent thermoplastic resin layers. Specifically, the difference in in-plane average refractive index is preferably 0.06 or less, more preferably 0.03 or less, and even more preferably 0.02 or less. From the above viewpoint, a lower difference in in-plane average refractive index is preferable, and the theoretical upper and lower limits are 0. Here, the difference in in-plane average refractive index is defined as the numerical difference between the largest and smallest in-plane average refractive index among the in-plane average refractive indexes of each thermoplastic resin layer constituting the unit forming the regularly arranged unit. The in-plane average refractive index of each thermoplastic resin layer is calculated by measuring the refractive index in the layer direction in both the film orientation axis direction and the direction perpendicular to it, and then taking the average of these values.

[0079] Furthermore, in the first projection image display member of the present invention, it is preferable that Rp2(60°) ≥ 20% is satisfied when the tangent surface at C2 is a reflective surface, and linearly polarized light containing only P-polarized components is incident from the transparent member 2 side along the incident surface including the orientation axis at C2 at an incident angle θ, and the average reflectance at wavelengths of 400 to 700 nm is determined as Rp2(θ).

[0080] The orientation axis direction (reference numeral 29 in Figure 14) at point C2 can be determined from the direction of the "orientation angle (reference numeral 30)" obtained by measurement with a phase difference measuring device, as described below (details of the determination method will be described later). Specifically, the direction indicated by the straight line extending from point C2 in the direction of the orientation angle is defined as the direction of the orientation axis (reference numeral 29 in Figure 14). This measurement method is usually used for samples in film or sheet form, but even in a structure combining a transparent member and a P-wave reflector (preferably using a laminated film), the transparent member often does not have a phase difference or orientation angle 30 considering the manufacturing method of its material, and the influence of its orientation axis 29 can be ignored, so the angle between the orientation axis at C2 and the reference axis C (orientation angle) can be easily analyzed. When analyzing the orientation axis direction of a projection image display member, the region including C2 to be measured can be cut out from the projection image display member by laser cutting or the like to obtain a sample and measure it.

[0081] In the projection image display member of the present invention, when linearly polarized light containing only the P-polarized component is incident from the transparent member 2 side along the incident plane containing the orientation axis at C2 at an incident angle θ, and the average reflectance at wavelengths of 400 to 700 nm is determined as Rp2(θ), if Rp2(60°) ≥ 20%, it becomes easy to achieve both the visibility of the landscape and the projection of the image. Linearly polarized light containing only the P-polarized component can be formed in the spectrophotometer measurement described later by setting the Gran Taylor polarizer attached to the device in a direction in which only the P-polarized component is emitted. In this state, the projection image display member is tilted in the orientation axis direction from the transparent member 2 side and P-polarized light is incident so that the angle with the normal to the reflective surface at C2 is 60° (in other words, the incident angle θ is 60°), and a spectral spectrum can be obtained and the average reflectance value can be determined (details of the measurement method for Rp2(θ) will be described later). By setting Rp2(60°)≧20%, the second region of the projection image display member can project an image sufficiently through the reflective effect of the light-reflecting material of the projection image display member, while ensuring the visibility of the landscape, even under incident angle conditions (Bruster angle conditions) where P-polarized light is not normally reflected.

[0082] The upper limit of Rp2(60°) is theoretically 100% according to the spectral measurement method described later. However, if Rp2(60°) is set excessively high, for example, when the projected image display member is used in a head-up display system for a vehicle, it will impair the visibility of the scenery behind the driver (observer) when viewing the second area of ​​the projected image display member. Therefore, from this perspective, Rp2(60°) is more preferably between 20% and 40%. Furthermore, by setting Rp2(60°) to 40% or less, reflections around the image projector on the dashboard are reduced, making the superimposition of the image and scenery on the projected image display member clearer. In addition, a lower Rp2(60°) increases the amount of light emitted by the image projector required to project the image clearly. Therefore, setting Rp2(60°) to 20% or more improves the projection quality of the image and also reduces device degradation due to heat accumulation during prolonged use. Considering these points, it is even more preferable that Rp2(60°) be between 20% and 35%. Rp2(60°) can be calculated using a known spectrophotometer by measuring the reflectance during P-wave irradiation at an incident angle θ in 1 nm increments, and using the resulting reflectance spectrum data (details of the measurement method will be described later).

[0083] To achieve Rp2(60°) of 20% or more or within the preferred range described above, it is preferable to use the laminated film described later as the P-wave reflector constituting the projected image display member. In particular, it is effective to adjust the difference in refractive index perpendicular to the film surface (perpendicular refractive index) between the thermoplastic resin layer with the largest refractive index perpendicular to the film surface and the thermoplastic resin layer with the smallest refractive index perpendicular to the film surface, as well as the number of layers, among the multiple thermoplastic resin layers constituting the regularly arranged unit of the laminated film. More specifically, it is preferable to set the difference in refractive index perpendicular to the film surface in the range of 0.02 to 0.12. On the other hand, if the difference in refractive index perpendicular to the film surface is made too large, the average transmittance of light with a wavelength of 400 to 700 nm incident perpendicularly to the laminated film surface will decrease, reducing the visibility of the scenery. Therefore, it is preferable that the difference in refractive index perpendicular to the film surface be in the range of 0.02 to 0.08. Furthermore, Rp2(60°) can be increased by increasing the number of layers.

[0084] Furthermore, the first projection image display member of the present invention uses the tangent plane at the center point C2 of the second region as a reflection surface, and linearly polarized light containing only the P polarization component at an incident angle θ is incident from the transparent member 2 side along the incident surface including the orientation axis at the center point C2. It is preferable that the average reflectance Rp2(θ) in the wavelength range of 400 to 700 nm thus obtained satisfies Rp2(20°) ≦ Rp2(40°) < Rp2(60°). The specific methods for specifying C2, the orientation axis, and θ are as described above.

[0085] In the case of a member composed of a general transparent material such as glass or a transparent resin material that does not contain a P-wave reflector, when the projection image display member is used as a reflection surface and the incident angle is gradually increased from the normal direction of the reflection surface to incident P-waves, the reflectance of the P polarization decreases, and the reflectance becomes minimal at the Brewster angle. Therefore, when P-polarized light components are projected as video light under the incident angle conditions near the Brewster angle, the visibility of the display image deteriorates because the reflectance is too low. Thus, when the second region of the projection image display member satisfies the relationship Rp2(20°) ≦ Rp2(40°) < Rp2(60°), there is no incident angle at which the reflectance shows a minimum like the Brewster angle. Therefore, when an image is projected onto the second region of the projection image display member from an oblique direction, the projected image can be clearly visualized.

[0086] In order to obtain such a relationship of light reflection characteristics, it is preferable to use a laminated film described later as the P-wave reflector constituting the projection image display member. In particular, while having thermoplastic resin layers with different refractive indices, among the thermoplastic resin layers constituting the regular arrangement of the laminated structure, the refractive index difference between the highest in-plane average refractive index and the lowest in-plane average refractive index is 0.03 or less, more preferably 0.02 or less, and the refractive index difference between the plane-direct refractive indices is 0.02 or more and 0.12 or less, more preferably 0.02 or more and 0.08 or less. This can be achieved by designing in this way.

[0087] In the first projection image display member of the present invention, when linearly polarized light containing only the P-polarized component is incident on the center point C2 of the second region at an incident angle of 60° from the transparent member 2 side, with the tangent surface at the center point C2 of the second region being the reflective surface, it is preferable that the change in average reflectance at a wavelength of 400 to 700 nm when the projection image display member is rotated in-plane within a range of 0° to 90° around C2, with the direction of the incident surface including the orientation axis being 0°, is 0% or more and 25% or less.

[0088] By using a projection image display element with a small change in reflectivity with respect to azimuth, the display quality of the image (multiple images, brightness) does not change significantly depending on the viewing direction, even when the projection image display element is viewed from any viewing angle, thus enabling wide-area image display.

[0089] To achieve these characteristics, it is preferable to use a laminated film, described later, as the P-wave reflector constituting the projected image display member, rather than a uniaxially stretched polarizing reflective film. In particular, this can be achieved by controlling the biaxial stretching process conditions so that the difference in refractive index between the orientation axis direction and the direction perpendicular to the orientation axis direction of the crystalline thermoplastic resin located on the outermost surface of the laminated structure is 0.05 or less, while having thermoplastic resin layers with different refractive indices (details of the biaxial stretching process will be described later).

[0090] Although the lower limit of the change in the average reflectance is 0%, if the average reflectance is constant in all directions, a preferred method for manufacturing a laminated film is to use a sequential biaxial stretching process that stretches sequentially in the longitudinal and width directions. However, when stretching in the width direction, a bowing phenomenon may occur where the orientation axis direction and phase difference are continuously different at the film width direction position. This change in the orientation axis caused by the bowing phenomenon may change the polarization state of the light emitted from the image projector after it has passed through the laminated film. For example, when light with a P-polarization component is irradiated, it may be converted into a mixed wave of P-polarization and S-polarization after passing through the film. This can result in undesirable reflections caused by S-polarization at the outermost surface of the projected image display member after passing through the laminated film, and as a result, the image reflected by the laminated film and the image reflected at the surface of the projected image display member after passing through the film may appear as a double image. Therefore, it is preferable that the laminated film used as a P-wave reflector is designed so that the stretching ratio is high in a specific direction, resulting in less change in the orientation axis direction in the width direction and so that the average reflectance of the film differs slightly in the in-plane rotation direction. Specifically, the change in reflectance is preferably 5% to 20%, and more preferably 10% to 20%.

[0091] To achieve this change in reflectivity, it is desirable to have a refractive index difference of 0.03 or more between the orientation axis direction and the direction perpendicular to the orientation axis direction of the crystalline thermoplastic resin located on the outermost surface of the laminated unit constituting the laminated film. Such a refractive index difference can be achieved by creating a difference in the stretching ratio in two orthogonal directions.

[0092] The following describes preferred constituent elements of a laminated film that can be used as a P-wave reflector in the projection image display member of the present invention.

[0093] The laminated film that can be used in the projection image display member of the present invention preferably has a unit in which 51 or more layers of two or more different thermoplastic resin layers are laminated in a certain regular arrangement.

[0094] In a laminated film that can be used in the projection image display member of the present invention, the thermoplastic resin layers are considered "different" if at least one of the following conditions is met: (1) the composition is different; (2) the glass transition temperature and melting point are different in differential scanning calorimetry (DSC); (3) the contrast of the stained image when observed in cross-section by transmission electron microscopy (TEM) is different; or (4) the dielectric constant (refractive index) of each thermoplastic resin layer obtained from electron energy loss spectroscopy (EELS measurement) is different.

[0095] "Different composition" means that the conditions for being considered to have "the same composition" as shown below are not met. "Same composition" means that the repeating units of the chemical structure of the thermoplastic resin constituting each thermoplastic resin layer are common at a rate of 95 mol% to 100 mol%, or that when comparing the constituent components of each thermoplastic resin layer, 95% to 100% of the components are common.

[0096] For example, regarding the former, in the case of polyethylene terephthalate, the main constituent unit is the ethylene terephthalate unit, which is formed by the ester bonding of ethylene glycol units and terephthalic acid units. However, if 95 mol% is common to both layers, even if some of the repeating units of the thermoplastic resin constituting the layers differ, such as a layer made of homopolyethylene terephthalate and a layer made of polyethylene terephthalate copolymerized with 4 mol% isophthalic acid, the main components of both layers are considered to be the same. Similarly, regarding the latter, even if some of the components constituting the thermoplastic resin layers differ, such as a layer made solely of homopolyethylene terephthalate and a layer containing 95% by mass of homopolyethylene terephthalate with the remaining 5% by mass being other components, if the amount of the difference is 5% by mass or less, the main components of both layers are considered to be the same. The specific composition / chemical structure of each thermoplastic resin layer can be determined by first determining the layer thickness of each thermoplastic resin layer according to the layer configuration method described later in the measurement method, then cutting and extracting the thermoplastic resin layer, or scraping the layer to expose it to the surface, and using infrared spectroscopy (FT-IR or nano-IR), gas chromatography / mass spectrometry (GC-MS), nuclear magnetic resonance (NMR), etc.

[0097] Next, we will explain "(2) Different glass transition temperatures and melting points in differential scanning calorimetry (DSC)". If it is difficult to identify the composition by the above method after extracting each thermoplastic resin layer, it is possible to determine that "the composition is different" by differential scanning calorimetry (DSC) if the thermoplastic resin layers constituting the laminated film exhibit different melting points and / or glass transition temperatures. In the case of a laminated film that can be used in the projection image display member of the present invention, exhibiting different melting points and different glass transition temperatures means that at least one of the melting point and the glass transition temperature differs by 0.1°C or more, preferably 2.0°C or more (in other words, it means that at least one of the difference in the melting point and the difference in the glass transition temperature of the thermoplastic resin layers is 0.1°C or more, preferably 2.0°C or more).

[0098] The easiest example to interpret is when differential scanning calorimetry is performed on a laminated film and two different glass transition points, crystallization temperatures (exothermic peaks), or melting points (endothermic peaks) are observed. On the other hand, in the measurement temperature range of 25°C to 300°C described in the differential scanning calorimetry (DSC) section of the measurement method described later, thermoplastic resin layers may not show a glass transition point or melting point. However, if one thermoplastic resin layer shows a glass transition point or melting point while the other does not, it can be interpreted as having a different composition, although it cannot be calculated as a temperature difference. For example, if two glass transition points are observed but only one melting point is observed, it can be estimated that one of the two thermoplastic resin layers is mainly composed of amorphous thermoplastic resin that does not have a melting point, and thus can be interpreted as having a different composition. Furthermore, in another embodiment, if two melting points can be identified, but only one or fewer glass transition temperatures or crystallization temperatures can be identified within the above temperature range, it can be presumed that the laminated film contains a layer mainly composed of a thermoplastic resin in a low-temperature region outside the temperature range, and thus the composition can be interpreted as being different. In this invention, DSC measurement can be performed by the method of JIS-K-7122 (1987), and details will be described later.

[0099] Next, we will explain "(3) The contrast of the stained image differs when observed in cross-section using a transmission electron microscope (TEM)." The two methods described above require the separation and analysis of the corresponding thermoplastic resin layer from the laminated film, and separation and analysis of the layers can be difficult. Therefore, to improve simplicity, if the layer interface can be recognized by the contrast difference in the cross-sectional image observed using a transmission electron microscope, and if it can be confirmed that the difference in the average brightness of two adjacent layers is greater than any of the standard deviations of brightness within each layer of the adjacent thermoplastic resin layer using the method described in the section on layer interface (contrast difference) in the measurement method described later, then the contrast of the stained image can be considered different, and it can be determined that the compositions of the adjacent thermoplastic resin layers are "different".

[0100] This contrast difference arises from differences in electron beam scattering, crystal diffraction, etc., between thermoplastic resin layers. Therefore, if the composition of the thermoplastic resin layers differs according to the aforementioned criteria, the crystallinity and electron density state will usually differ, and the electron staining state will also differ. Consequently, when there are thermoplastic resin layers with different compositions, it becomes possible to visualize each thermoplastic resin layer as a layered structure with contrast differences in the cross-sectional image of the laminated film.

[0101] In the case of a laminated film having a unit in which two thermoplastic resin layers of different compositions are alternately laminated, if the same thermoplastic resin layer exhibits a constant brightness, then when the depth in the thickness direction is shown on the horizontal axis and the brightness / contrast (gray level in grayscale display) at each point is shown on the vertical axis, the graph will fluctuate up and down between the brightness values ​​of two points, as shown in Figure 15. In Figure 15, reference numerals 31 to 33, respectively, represent the graph showing the relationship between the depth in the thickness direction and the contrast (gray level) of a laminated film having an AB regular arrangement, the thickness of layer A, and the thickness of layer B (however, in this embodiment, layer A is assumed to be a layer with relatively high crystallinity).

[0102] On the other hand, in the case of a laminated film having three different types of thermoplastic resin layers (layer A, layer B, and layer C), each thermoplastic resin layer exhibits a constant brightness. Therefore, if the depth in the thickness direction is plotted on the horizontal axis and the brightness / contrast (gray level in grayscale display) at each point is plotted on the vertical axis, a graph showing a stepwise change in brightness is obtained, as shown in Figures 16 and 17. Figures 16 and 17 are schematic diagrams showing the relationship between the depth in the thickness direction and the contrast difference (gray level) in a cross-sectional observation image of one embodiment of a laminated film having a regular arrangement of (ABCB)n (where n is a natural number indicating the number of repetitions). In Figures 16 and 17, reference numerals 31 to 34 represent, respectively, the spectrum showing the relationship between the depth in the thickness direction and the change in contrast (gray level) of a laminated film having an ABCB regular arrangement, the thickness of layer A, the thickness of layer B, and the thickness of layer C.

[0103] Next, we will explain "(4) The dielectric constant (refractive index) of each thermoplastic resin layer obtained from electron energy loss spectroscopy (EELS measurement) is different." Furthermore, a laminated film that can be used in the projection image display member of the present invention may also be judged to have a "different composition" if the refractive index (dielectric constant) of the thermoplastic resin layer is different. A thermoplastic resin layer with a different refractive index is determined from the dielectric constant and refractive index of each thermoplastic resin layer obtained from electron energy loss spectroscopy (EELS measurement) according to the method described in the measurement method section below. More specifically, it can be determined by the following procedure. First, the main orientation axis direction of the laminated film is identified using a phase difference measuring device (for example, the phase difference measuring device KOBRA-WPR manufactured by Oji Keisokuki Co., Ltd.), and a cross-sectional sample of the laminated film is obtained so as to include that direction and the thickness direction of the laminated film. Next, an electron beam is irradiated onto each thermoplastic resin layer in the cross-sectional sample, and the dielectric constant at a loss energy of 2.5 eV is read by analyzing its dielectric constant. If the difference in the dielectric constant of the obtained thermoplastic resin layers is 0.01 or more, it is judged that the refractive index of the thermoplastic resin layer is "different".

[0104] According to Maxwell's electromagnetic theory, in non-magnetic materials that absorb very little light, such as the thermoplastic resin (described later) that can be suitably used in the laminated film that can be used in the projection image display member of the present invention, the dielectric constant is generally equal to the square of the refractive index. Therefore, if the dielectric constant of the thermoplastic resin layer is different, it can be determined that the refractive index of the thermoplastic resin layer is different, and the relative magnitudes of the dielectric constants of the thermoplastic resin layers correspond to the relative magnitudes of their refractive indices.

[0105] If the dielectric constant difference of each thermoplastic resin layer cannot be analyzed using a cross-sectional sample, the position corresponding to each thermoplastic resin layer can be identified using scanning transmission electron microscopy (STEM) observation, and a thin section sample can be obtained by cutting in a direction parallel to the surface of the laminated film. The dielectric constant of each thermoplastic resin layer can be analyzed from EELS measurements, and it can be determined that the refractive indices of the thermoplastic resin layers are "different".

[0106] The thermoplastic resin used in the laminated film that can be used in the projection image display member of the present invention includes chain polyolefins such as polyethylene, polypropylene, poly(4-methylpentene-1), and polyacetal; alicyclic polyolefins which are ring-opening metathesis polymers, addition polymers, and addition copolymers with other olefins of norbornene; biodegradable polymers such as polylactic acid and polybutyl succinate; polyamides such as nylon 6, nylon 11, nylon 12, and nylon 66; polypropylene terephthalate, polyethylene terephthalate, polybutylene terephthalate, and polyethylene-2,6-naphthalate. Polyesters such as t, aramids, polymethyl methacrylate, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl butyral, ethylene vinyl acetate copolymer, polyacetal, polyglycolic acid, polycarbonate, polyethersulfone, polyetheretherketone, modified polyphenylene ether, polyphenylene sulfide, polyetherimide, polyimide, polyarylate, tetrafluoroethylene resin, trifluoroethylene resin, trifluoroethylene chloride resin, tetrafluoroethylene-hexafluoropropylene copolymer, and polyvinylidene fluoride can be used. Among these, polyester is particularly preferred from the viewpoint of strength, heat resistance, transparency, and versatility. These may be copolymers or mixtures of two or more resins.

[0107] Polyester refers to a resin having a molecular structure in which dicarboxylic acid units and diol units are linked by ester bonds. Preferred polyesters are those obtained by polymerization from monomers mainly composed of aromatic dicarboxylic acids or aliphatic dicarboxylic acids and diols. Examples of aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 4,4′-diphenyldicarboxylic acid, 4,4′-diphenyletherdicarboxylic acid, and 4,4′-diphenylsulfondicarboxylic acid. Examples of aliphatic dicarboxylic acids include adipic acid, suberic acid, sebacic acid, dimer acid, dodecanedionic acid, cyclohexanedicarboxylic acid, and their ester derivatives. Among these, terephthalic acid, isophthalic acid, and 2,6-naphthalenedicarboxylic acid, which exhibit high refractive indices, are preferred. These acid components may be used individually, or two or more may be used in combination. Furthermore, oxy acids such as hydroxybenzoic acid may be partially copolymerized.

[0108] Examples of diol components include ethylene glycol (polyethylene glycol), 1,2-propanediol, 1,3-propanediol, neopentyl glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, diethylene glycol, triethylene glycol, polyalkylene glycol, 2,2-bis(4-hydroxyethoxyphenyl)propane, isosorbate, and spiroglycol. Among these, ethylene glycol is preferred. These diol components may be used individually or in combination of two or more.

[0109] The thermoplastic resin corresponding to the main component of the thermoplastic resin layer constituting the laminated film that can be used in the projection image display member of the present invention is preferably selected from among the polyesters mentioned above, such as polyethylene terephthalate and its polymer, polyethylene naphthalate and its copolymer, polybutylene terephthalate and its copolymer, polybutylene naphthalate and its copolymer, and further, polyhexamethylene terephthalate and its copolymer, and polyhexamethylene naphthalate and its copolymer. The main component refers to the component that is included in the thermoplastic resin in an amount of 50% by mass or more and 100% by mass or less.

[0110] A preferred combination of thermoplastic resins constituting different thermoplastic resin layers in a laminated film that can be used in the projection image display member of the present invention is one in which the basic structure of the thermoplastic resins is the same. By adopting this configuration, delamination between layers becomes less likely to occur. The basic structure referred to here is the repeating unit that constitutes the thermoplastic resin and is the most abundant unit. For example, if the thermoplastic resin is polyethylene terephthalate, then its basic structure is the ethylene terephthalate skeleton. For example, when polyethylene terephthalate is used as one of the thermoplastic resins, it is preferable to include the ethylene terephthalate skeleton, which is the same basic structure as polyethylene terephthalate, from the viewpoint of easily realizing a high-precision laminated structure. When thermoplastic resins having different optical properties are resins that contain the same basic structure, the lamination accuracy is increased, and delamination between layers at the lamination interface becomes less likely to occur.

[0111] Furthermore, various additives, such as antioxidants, heat stabilizers, weather stabilizers, UV absorbers, organic lubricants, pigments, dyes, organic or inorganic fine particles, fillers, antistatic agents, and nucleating agents, can be added to each thermoplastic resin layer, either individually or in combination, to the extent that they do not impair its properties.

[0112] The laminated film that can be used in the projection image display member of the present invention preferably has a laminated unit in which 51 or more layers of two or more different thermoplastic resin layers are laminated in a certain regular arrangement. If the layers are defined as A, B, C, etc. in order from the outermost layer, then specific examples of such configurations include (AB)n (where n is a natural number indicating the number of repetitions, the same applies hereinafter) when it consists of two types of resin, and when it consists of three types of thermoplastic resin layers, for example, configurations such as (ABC)n, (ABCB)n, (ABAC)n, (ABCAB)n, (ABCAC)n, (ABABC)n, (ABCBCB)n can be given. In addition, for these configurations, the surface layers on both sides may be made the same, such as (ABC)nA, in order to improve film formation.

[0113] In the laminated film that can be used in the projection image display member of the present invention, it is preferable that the thermoplastic resin layer that forms the outermost layer of the laminated unit (corresponding to layer A in each of the configurations shown above) is mainly composed of crystalline thermoplastic resin A. If all the thermoplastic resin layers constituting the laminated film are amorphous, when stretching is performed in the biaxial stretching manufacturing method, stress does not occur and uneven stretching may occur, and the uniformity of the physical properties of the resulting laminated film may be greatly impaired. In the above embodiment, by having the main component of at least layer A, which is the outermost layer, be a crystalline resin, it becomes possible to physically and chemically grasp and co-stretch the other thermoplastic resin layers that are laminated at the same time. Crystallinity can be determined by cutting and extracting the thermoplastic resin layer and using a differential scanning calorimetry (DSC) device to see if the melting point (endothermic peak) shows a heat amount of 3 J / g or more (if this is not met, it is considered amorphous).

[0114] In the laminated film that can be used in the projection image display member of the present invention, it is preferable that the crystalline thermoplastic resin layer (layer A in the above embodiment) is located on the outermost surface on both sides. By making the thermoplastic resin layer located on the outermost surface a layer mainly composed of crystalline thermoplastic resin, adhesion of the laminated film to rolls, clips, etc. during the manufacturing process is less likely to occur, and stretching defects, deterioration of the surface condition, and process contamination are less likely to occur.

[0115] The laminated film that can be used in the projection image display member of the present invention preferably has a laminated unit in which 51 or more layers of two or more different thermoplastic resin layers are laminated in a certain regular arrangement, preferably 401 or more layers, and more preferably 801 or more layers. By adopting this configuration, a light interference reflection function at the layer interface can be expressed. From the above viewpoint, a larger number of layers constituting the regular arrangement is preferable, but from the viewpoint of avoiding the enlargement of the manufacturing equipment, the upper limit is preferably 2001 layers. Such a laminated film having a certain regular arrangement can be formed, for example, by laminating multiple different types of thermoplastic resins by the method shown below.

[0116] For simplicity, the following description focuses on laminated films consisting mainly of two types of thermoplastic resin layers, outlining their manufacturing methods and preferred design requirements. However, for manufacturing methods of laminated films using three or more types of thermoplastic resins, the same interpretation can be applied by substituting "two types" for "three or more types" in the following descriptions unless otherwise specified. Furthermore, the preferred design requirements can be similarly interpreted by substituting the relationship between the thermoplastic resin layer with the highest refractive index and the resin with the lowest refractive index to satisfy the following relationship. In the following explanation, crystalline thermoplastic resins are referred to as thermoplastic resin A, and amorphous resins as thermoplastic resin B (in the case of three types, thermoplastic resin C may be either crystalline or amorphous).

[0117] First, each thermoplastic resin is prepared in the form of pellets or other materials, dried in hot air or under vacuum as needed, and then supplied to separate extruders. Inside the extruders, the pellets are heated and melted to a temperature above their melting point, and the extrusion rate is made uniform using a gear pump or the like to push out the resin. After that, foreign matter and modified resin are removed through a filter or the like. Next, the two types of molten thermoplastic resins are fed into a multilayer lamination device through separate channels and laminated alternately.

[0118] As a multilayer lamination apparatus, a multi-manifold die, a feed block, and a static mixer can be used, but it is particularly preferable to use a feed block having 51 or more, preferably 401 or more, and more preferably 801 or more fine slits. Using such a feed block prevents the apparatus from becoming excessively large, resulting in less foreign matter due to thermal degradation and enabling high-precision lamination even when the number of layers is extremely large. Furthermore, the lamination accuracy in the width direction is also significantly improved compared to conventional technology. In addition, with such an apparatus, the thickness of each layer can be adjusted by the shape (length, width) of the slits, and the number of layers can be adjusted by the number of slits, making it easy to achieve any desired layer thickness and number of layers. The number of slits corresponds to the total number of laminated films, and the number of layers can be easily increased by increasing the number of slits. However, from the viewpoint of avoiding the apparatus becoming excessively large, the upper limit of the number of slits is preferably 2001.

[0119] Furthermore, the layer thickness distribution of the laminated film that can be used in the projection image display member of the present invention is preferably such that the multiple thermoplastic resin layers forming a regular arrangement exhibit a specific optical thickness relationship. In particular, in the case of a laminated film used for a head-up display system in a vehicle, the optical thickness under oblique viewing angle conditions is important, and it is especially preferable that the following optical thickness relationship holds with respect to the refractive index in the thickness direction. For example, if the laminated film consists of two types of thermoplastic resin layers, it is preferable that it satisfies the relationship of equation (1), and if it consists of three types of thermoplastic resin layers, it is preferable that it satisfies the relationship of equation (2). Here, λ is the reflection wavelength, nA is the refractive index perpendicular to the plane of layer A, dA is the total layer thickness of layer A included in the regular arrangement, nB is the refractive index perpendicular to the plane of layer B, dB is the total layer thickness of layer B included in the regular arrangement, nC is the refractive index perpendicular to the plane of layer C, dC is the total layer thickness of layer C included in the regular arrangement, and k is the order (natural number).

[0120]

number

[0121]

number

[0122] The layer thickness distribution of the laminated film that can be used in the projection image display member of the present invention is preferably one of the following: a constant layer thickness distribution from one side of the laminated film surface to the opposite side; a layer thickness distribution that increases or decreases monotonically from one side of the laminated film surface to the opposite side; a layer thickness distribution that increases and then decreases from one side of the laminated film surface towards the center of the film; a layer thickness distribution that decreases and then increases from one side of the laminated film surface towards the center of the film; or a combination of these distributions.

[0123] Preferred layer thickness distributions include linear, geometric, and difference sequences, which change continuously, as well as distributions where approximately 10 to 50 layers have roughly the same thickness, with the thickness changing in a step-like manner. By adjusting the layer thickness distribution, a distribution is created in the optical thickness of adjacent layer pairs, allowing control over the width of the reflection bandwidth. In particular, a layer thickness distribution that monotonically increases or decreases from one side of the laminated film to the other is preferred because, compared to other layer thickness distributions with multiple gradients, it reduces the number of layers with the same thickness, thereby suppressing repeated reflections between layers with the same thickness and reducing interference color unevenness that may occur when projecting an image.

[0124] In the laminated film that can be used in the projection image display member of the present invention, a protective layer may preferably be provided on both surface layers, with a thickness of 1% or more of the total thickness of the laminated film, and preferably the thickness of the protective layer is 4% or more of the total thickness of the laminated film. The protective layer may be a thermoplastic resin A layer, or it may be formed by individually laminating thermoplastic resins different from thermoplastic resins A and B layers that form a regular arrangement. Increasing the thickness of the protective layer leads to suppression of lamination disorder during film formation, improvement of the accuracy of the actual layer thickness of each layer relative to the design, suppression of deformation of the thin film layer in the multilayer laminated film during and after the lamination process with other films or molded articles, and improved pressure resistance.

[0125] The thickness of the laminated film that can be used in the projection image display member of the present invention is not particularly limited, but is preferably, for example, 20 μm or more and 300 μm or less. If it is 20 μm or more, the stiffness of the laminated film is increased, ensuring good handling. If it is 300 μm or less, the stiffness of the laminated film is not excessively strong, improving moldability and making it easier to process into transparent image display members with complex shapes.

[0126] Furthermore, functional layers such as a primer layer, hard coat layer, abrasion-resistant layer, scratch-resistant layer, anti-reflective layer, color correction layer, ultraviolet absorption layer, light-stabilizing layer, heat-absorbing layer, printing layer, gas barrier layer, and adhesive layer may be formed on at least one surface of the laminated film that can be used in the projection image display member of the present invention. These layers may be single-layer or multi-layer, and one layer may have multiple functions. The laminated film may also contain additives such as ultraviolet absorbers, light stabilizers (HALS), heat-absorbing agents, crystal nucleating agents, and plasticizers. These components can also be used in combination, as long as they do not impair the effects of the present invention.

[0127] As described above, the molten laminate is formed into a sheet using a die and extruded onto a cooling body such as a casting drum to cool and solidify, thereby obtaining a cast sheet. In this process, it is preferable to use electrodes such as wire, tape, needle, or knife-shaped electrodes to rapidly cool and solidify the molten sheet by using electrostatic force to bring it into close contact with the cooling body such as a casting drum. Alternatively, it is also preferable to blow air from a slit-shaped, spot-shaped, or surface-shaped device to rapidly cool and solidify the molten sheet by bringing it into close contact with the cooling body such as a casting drum, or to rapidly cool and solidify it by bringing it into close contact with the cooling body using a nip roll.

[0128] Subsequently, it is preferable to biaxially stretch the obtained cast sheet in the longitudinal and width directions. The stretching may be performed sequentially or simultaneously. Furthermore, if necessary, further stretching may be performed in the longitudinal and / or width directions.

[0129] First, let's explain the case of sequential biaxial stretching. In the case of sequential biaxial stretching, it is preferable to stretch in the width direction after stretching in the longitudinal direction. Here, stretching in the longitudinal direction refers to the first axial stretching to give the cast sheet a longitudinal molecular orientation, and is usually performed by the difference in peripheral speed of the rolls. Stretching in the longitudinal direction may be performed in one stage using a pair of rolls, or in multiple stages using multiple pairs of rolls. The stretching ratio varies depending on the type of thermoplastic resin constituting the laminated film, but is usually preferably 2.00 to 10.0 times, and when polyethylene terephthalate is used in one of the thermoplastic resins constituting the laminated film, 2.50 to 7.00 times is particularly preferred. Furthermore, it is preferable to set the stretching temperature within the range of the glass transition temperature of the thermoplastic resin with the highest glass transition temperature among the thermoplastic resin layers constituting the laminated film to that glass transition temperature + 100°C. When using a thermoplastic resin with polyethylene terephthalate or polyethylene naphthalate as the basic framework for one of the crystalline thermoplastic resins constituting the laminated film, in order to show the in-plane refractive index difference conditions that can be preferably used as a P-wave reflector, a stretching ratio in the longitudinal direction of 2.70 to 3.20 times, which is lower than the stretching conditions in the width direction described later, is preferably used.

[0130] The uniaxially oriented film obtained in this way may be subjected to surface treatments such as corona treatment, flame treatment, or plasma treatment as needed, and then an easy-adhesion layer with functions such as slipperiness, easy adhesion, and antistatic properties may be applied by in-line coating. In the in-line coating process, the easy-adhesion layer may be applied to one side of the laminated film, or it may be applied to both sides of the laminated film simultaneously or sequentially to one side at a time.

[0131] Next, the uniaxially oriented film is stretched in the width direction. Stretching in the width direction refers to a second axial stretch to give the sheet a width-direction orientation, and is usually performed using a tenter, where the sheet is conveyed while gripping both ends in the width direction with multiple clips. The stretching ratio varies depending on the type of thermoplastic resin constituting the laminated film, but is generally 2.00 to 10.0 times preferred. When polyethylene terephthalate or polyethylene naphthalate is used as one of the crystalline thermoplastic resins constituting the laminated film, 2.50 to 7.00 times is particularly preferred. The stretching temperature is preferably from the glass transition temperature of the thermoplastic resin with the highest glass transition temperature among the thermoplastic resins constituting the laminated film to that glass transition temperature + 120°C. When polyethylene terephthalate or polyethylene naphthalate is used as one of the crystalline thermoplastic resins constituting the laminated film, in order to show the in-plane refractive index difference conditions that can be preferably used as a P-wave reflector, it is preferable to stretch the film longitudinally at the preferred ratio and then stretch it in the width direction by 3.20 to 6.00 times. By strongly stretching the film in the width direction, a more uniform spectral distribution, phase difference, and orientation can be obtained over a wide area in the width direction of the film surface.

[0132] The biaxially stretched laminated film is then subjected to further heat treatment in a tenter, where the temperature is between the stretching temperature and the melting point. After that, it is uniformly cooled slowly to room temperature and then wound up. At this time, in order to make the orientation of the laminated film more uniform, it is preferable to have a gentle gradient in the temperature conditions of the stretching and heat treatment processes. The temperature gradient is carried out within a temperature range that is above the glass transition temperature of the thermoplastic resin with the highest glass transition temperature constituting the laminated film, and below the crystallization temperature of the thermoplastic resin with the highest crystallization temperature. Furthermore, it is preferable that there are two or more temperature gradients before reaching the heat treatment temperature.

[0133] As a method to reduce shrinkage force after the stretching process and further improve the uniformity of orientation in the width direction, it is preferable to lower the heat treatment temperature to reduce the shrinkage force toward the stretching process in the longitudinal direction, or to extend the intermediate region between the stretching process and the heat treatment process, and to increase the rigidity of the film by providing a temporary constant temperature or low temperature region (a region where the stretching temperature + 30°C ≥ the intermediate region temperature). In addition, it is also preferable to suppress the shrinkage force in the longitudinal direction and then stretch the laminated film slightly during the heat treatment process to create a tensioned state. From the viewpoint of achieving both a thermal shrinkage balance and orientation that takes into account processability for projection image display members, the magnification of the slight stretching is 1.03 times or more and 1.18 times or less, more preferably 1.05 times or more and 1.10 times or less.

[0134] Furthermore, if necessary, to impart a low orientation angle and thermal dimensional stability of the sheet, a relaxation treatment in the longitudinal and / or widthwise directions may be used in combination with the slow cooling of the laminated film during the cooling process after the heat treatment process. In addition, to adjust the thermal shrinkage rate at low temperatures, it is preferable to perform slight stretching in the section of this slow cooling process where the film temperature is above the temperature to which the thermal shrinkage rate is to be adjusted. It is also preferable to perform pseudo-slight stretching by increasing the tension (draw) in the winding process after slow cooling. These methods may be combined as appropriate.

[0135] In order to improve the wide-area visibility of the image display according to the present invention, when polyethylene terephthalate or polyethylene naphthalate is used in at least one of the thermoplastic resins A and B that constitute the laminated film, it is preferable that the ratio of the stretching ratio in the width direction to the stretching ratio in the longitudinal direction (a value greater than 1 between the stretching ratio in the width direction and the stretching ratio in the longitudinal direction, or the stretching ratio in the longitudinal direction and the stretching ratio in the width direction) is 1.05 or more and 2.00 or less. When the stretching ratio is 1.05 or more, the difference in refractive index between the orientation axis direction and the direction perpendicular thereto is sufficient, and the orientation in the width direction becomes more uniform, so even when displaying an image over a wide area or when displaying an image at a wide viewing angle, it becomes difficult to see partially multiple images. When the stretching ratio is 2.00 or less, the orientation in a particular direction is not too strong, and problems such as reduced film-forming properties such as tearing of the laminated film, poor processing appearance due to high thermal shrinkage in the stretching direction, and azimuth dependence of image display are reduced. A more preferable draw ratio that can achieve both orientation uniformity and processability is 1.15 to 1.80, more preferably 1.30 to 1.80, and particularly preferably 1.50 to 1.80. The draw ratio in the width direction mentioned here refers to the draw ratio including the additional draw ratio in the heat treatment process.

[0136] The laminated film produced by the above-described preferred manufacturing method can be made to have a large difference between the refractive index in the orientation axis direction and the refractive index perpendicular to the orientation axis by using process conditions that stretch the film moderately strongly in a specific direction. Preferably, the difference between the in-plane refractive index of the crystalline thermoplastic resin A layer in the orientation axis direction and the in-plane refractive index of the crystalline thermoplastic resin A layer in the direction perpendicular to the orientation axis (in-plane refractive index difference of layer A) is 0.03 or more and 0.10 or less. Specifically, this in-plane refractive index difference can be achieved by designing the ratio of stretching in the longitudinal direction to stretching in the width direction of the laminated film, the stretching speed in the width direction, and the additional stretching ratio in the heat treatment process to the preferred conditions in the manufacturing method described later.

[0137] On the other hand, if the refractive index difference between the orientation axis direction and the direction perpendicular to the orientation axis of layer A is too large, it can lead to a problem where the dependence of the light reflectance on the viewing angle is large. Therefore, the upper limit of this refractive index difference is more preferably 0.05. Such a laminated film with a large in-plane refractive index difference of thermoplastic resin layer A is particularly preferable to use as a P-wave reflector in the projection image display member of the present invention because it reduces the possibility of multiple images being generated due to the orientation angle of the film and provides the advantage of projecting a clear image over a wide range and wide viewing angle.

[0138] Next, we will explain the case of simultaneous biaxial stretching. In the case of simultaneous biaxial stretching, the obtained cast sheet may be subjected to surface treatments such as corona treatment, flame treatment, or plasma treatment as needed, and then functions such as slipperiness, adhesion, and antistatic properties may be imparted by in-line coating. In the in-line coating process, the adhesion layer may be applied to one side of the laminated film, or it may be applied to both sides of the cast sheet simultaneously or sequentially, one side at a time.

[0139] Next, the cast sheet is guided to a simultaneous biaxial tenter, where it is transported while gripping both ends in the width direction with clips, and stretched simultaneously and / or in stages in the longitudinal and width directions. Simultaneous biaxial stretchers can be of the pantograph type, screw type, drive motor type, or linear motor type, but it is preferable to use a drive motor type or linear motor type, which allows for arbitrary changes in the stretching ratio and relaxation processing at any desired location. The stretching ratio varies depending on the type of resin constituting the laminated film, but typically, an area stretching ratio of 6 to 50 times is preferred, and when polyethylene terephthalate is used as one of the thermoplastic resins constituting the laminated film, an area stretching ratio of 8 to 30 times is particularly preferred. To strongly express orientation in a specific direction within the plane, it is preferable to use different stretching ratios for the longitudinal and width directions. The stretching speed may be the same, or it may be stretched in the longitudinal and width directions at different speeds. Furthermore, the stretching temperature is preferably between the glass transition temperature of the thermoplastic resin with the highest glass transition temperature among the thermoplastic resins constituting the laminated film and the glass transition temperature + 120°C.

[0140] The sheet, thus simultaneously biaxially stretched, is preferably subjected to further heat treatment in a tenter, at a temperature above the stretching temperature and below the melting point of the thermoplastic resin constituting the crystalline thermoplastic resin layer constituting the laminated film, in order to impart flatness and dimensional stability. During this heat treatment, it is preferable to instantly relax the sheet in the longitudinal direction immediately before and / or immediately after entering the heat treatment zone in order to suppress the distribution of the main orientation axis in the width direction. After heat treatment in this manner, the sheet is uniformly cooled slowly and then cooled to room temperature before being wound up. In addition, if necessary, relaxation treatment may be performed in the longitudinal and / or width directions during slow cooling after heat treatment. Instantaneous relaxation treatment in the longitudinal direction immediately before and / or immediately after entering the heat treatment zone. The stretching ratio and other conditions can be the same as those used for sequential biaxial stretching described above.

[0141] The laminated film obtained in the manner described above is trimmed to the required width via a winding device and wound up in a roll to prevent winding creases. Furthermore, embossing may be applied to both ends of the sheet during winding to improve its appearance.

[0142] The head-up display system of the present invention will now be described. The head-up display system of the present invention comprises a first projection image display member of the present invention and an image projector 1 that projects an image by irradiating light with a P-polarization component ratio of 51% or more and 100% or less, wherein the P-wave reflector of the projection image display member is located on the light irradiation surface side of the colored layer, and when the region on the projection image display member where the colored layer is provided is defined as the first region, the image projector 1 projects an image onto the first region.

[0143] In the head-up display system of the present invention, the image projector refers to a device capable of irradiating a light-reflecting area with the light of an image. The image projector constituting the head-up display system of the present invention is not particularly limited as long as it can irradiate a light-reflecting area with the light of an image. However, when projecting an image at a single focal length, common image projectors include liquid crystal projectors, RGB lasers, DLP (Digital Light Processing), LCOS (Liquid crystal on silicon), liquid crystals, organic EL, micro-LEDs, mini-LEDs, and light-emitting devices equipped with these. On the other hand, a multi-focal-display image projector can also be used for the purpose of reducing the observer's eye movement by simultaneously projecting displays with different focal lengths. In this case, a mirror-reflection type image projector that combines a reflective mirror and a magnifying mirror inside the main body in addition to the light-emitting device, or a ride-guide type image projector that emits light from a light-emitting device to a light guide member and converts the emission angle and emission range of the light beam for projection can be used. These image projectors can be freely selected considering the installation position, installation space capacity, installation angle, image projection position on the projection display member, brightness and color gamut of the resulting image, and viewing angle. Although a second image projector will be described later, the first and second image projectors may be the same or different.

[0144] The head-up display system of the present invention comprises a first projected image display member of the present invention. The first projected image display member of the present invention can be manufactured by the method described above.

[0145] The head-up display system of the present invention must include an image projector 1 that projects an image by irradiating light with a P-polarization component ratio of 51% to 100%. The presence of a high P-polarization component in the light rays constituting the image projected from the image projector 1 is important for suppressing multiple images caused by undesirable reflected light reflected at the interface between the transparent material on the surface of the projected image display member and the air, and for maintaining image brightness when wearing polarized sunglasses that cut S-polarization. From these viewpoints, a higher proportion of the P-polarization component in the light rays emitted from the image projector 1 is preferable, preferably 90% or more, and more preferably 99% or more. For the reasons stated above, there is no particular upper limit to the proportion of the P-polarization component in the light emitted from the image projector 1; theoretically, it can be 100%.

[0146] Furthermore, in order to increase the proportion of P-polarized light in the image, a linear polarizer can be retrofitted to control the direction of polarization vibration of the light emitted from the image projector. Examples of linear polarizers that can be used in the head-up display system of the present invention include, for example, a polyvinyl alcohol film impregnated with iodine or a dichroic dye and stretched in one axis direction, with both surfaces laminated with a protective film; a wire grid type polarizing reflector with metal wiring arranged in one direction on a transparent substrate; and a polarizing reflective film made by alternately laminating two different types of thermoplastic resins and stretching in one direction (for example, Japanese Patent Application Publication No. 2009-37235). By using a linear polarizer, the direction of light that passes through the linear polarizer is controlled in the direction of the transmission axis of the linear polarizer. Therefore, it is preferable to install the linear polarizer so that its transmission axis coincides with the intersection line of the surface of the linear polarizer and the surface that includes the electric field vibration direction that results in P-polarization with respect to the incident surface when the projected image display member is the reflective surface.

[0147] In the head-up display system of the present invention, it is preferable that the light emitted from the image projector 1 does not have, or has, one peak with a full width at half maximum of 15 nm or less in the wavelength range of 400 to 800 nm. The laminated film used as a P-wave reflector exhibits light reflection characteristics by laminating different thermoplastic resins in a certain regular arrangement, but when its spectral distribution is measured, fine fluctuations (ripples) in light reflectance due to the multilayer laminated structure occur in the visible light region. Furthermore, in the case of light-reflecting materials that utilize optical interference reflection due to a multilayer laminated structure such as such a laminated film, the spectral distribution easily shifts to the shorter or longer wavelength side depending on the viewing angle, so when focusing on a specific wavelength, the reflectance may fluctuate finely depending on the viewing angle due to the effect of ripples. When projecting an image onto a first region with a colored layer of a projection image display member using a laminated film exhibiting such ripples as a P-wave reflector, changes in the color tone of the image depending on the viewing angle become more visible, which may reduce the visibility of the image. Therefore, when using such a laminated film as a P-wave reflector, it is preferable to project the image with light that does not contain or has only a small peak in the full width at half maximum.

[0148] As an image projector that does not contain, or contains one or fewer, peaks with a full width at half maximum of 15 nm or less, examples of liquid crystal displays that can be used include a liquid crystal display that uses a white LED combining a blue LED and a Y3Al5O12:Ce(YAG) phosphor as a backlight source, as shown in the emission spectrum in Figure 18, or a liquid crystal display equipped with a three-wavelength white LED that uses a sulfide-based blue phosphor such as SrGa2S4:Eu(SGS) or CaS:Eu(CS) as the blue phosphor, Si6-zAlzOzN8-z:Eu(βSiAlON) as the green phosphor with a wavelength range of 500 nm to 580 nm, and (Sr,Ca)AlSiN3:Eu(SCASN) or CaAlSiN3:EU(CASN) as the red phosphor with a wavelength range of 570 nm to 700 nm, respectively, in order to further improve the color gamut. Furthermore, any image projector equipped with a light source that emits light without or containing one or fewer peaks with a full width at half maximum of 15 nm or less is suitable as image projector 1, and is not limited to displays having the configuration described herein. Other image projectors with different light emission methods can also be suitably used as image projector 1.

[0149] In the head-up display system of the present invention, the image projector 1 used to project an image onto the area provided with a colored layer, when intended for application to a vehicle such as an automobile, can display information normally displayed on the instrument panel, such as speed display navigation information, or signage such as approaching vehicle indicators and hazard indicators, in the first area. From this viewpoint, an image projector capable of illuminating light with a wide viewing angle can preferably be used in the first area. A single image projector may have a wide viewing angle characteristic and be able to display an image over a wide area, or it may be possible to project over a wide area by providing multiple light sources. Furthermore, two or more light sources (image projectors) can be arranged side by side on or inside the dashboard, and different images can be displayed in conjunction or independently.

[0150] In the head-up display system of the present invention, the P-wave reflector is positioned on the light-emitting surface side of the colored layer, and it is important that the image is projected from the image projector 1 to the first region, where the region with the colored layer is defined as the first region in the projection image display member. To achieve this configuration, the first projection image display member of the present invention, as described above, should be designed such that each component is positioned with the colored layer facing downwards, and the projection image display member, which is installed below the colored layer, projects the image onto the first region. Furthermore, because the P-wave reflector is positioned on the light-emitting surface side of the colored layer, the light emitted from the image projector can reach the P-wave reflector without being absorbed by the colored layer and reducing the brightness of the image, thus allowing the image reflected by the P-wave reflector to be clearly visible.

[0151] The head-up display system of the present invention preferably further comprises an image projector 2 that projects an image by irradiating light with a P-polarization component ratio of 51% or more and 100% or less. In this configuration, the image projectors 1 and 2 each irradiate light individually to the first and second regions, respectively, and different images can be displayed in the first and second regions. For example, not only is it possible to have one image projector each for projecting images into the first and second regions, but one image projector can also have two light sources and irradiate light simultaneously in two directions (first region and second region). However, as will be described later, in the case of an image projector capable of projecting an image with a focal length preferably used as image projector 2, the arrangement of components such as mirrors inside the image projector becomes very complicated, and it may be necessary to provide a large installation space inside the dashboard, which may cause problems in vehicle design.

[0152] In the head-up display system of the present invention, the image projector 2 used to project an image onto the second area is preferably a mirror-reflection type image projector that combines a light source unit that illuminates an image internally with a curved mirror. Since the second area has the function of visually overlaying the scenery from the car window with the image, it is preferable to use an image projector that enables multi-focus display in order to reduce the observer's eye movement by simultaneously projecting displays with different focal points.

[0153] In the head-up display system of the present invention, the image projector 2 is preferably a display capable of high-brightness display so that the image can be seen even in a bright external environment. In addition, displays using high-brightness LEDs as backlights, liquid crystal displays having direct-type or edge-type backlights with a white reflective film or a specular reflective film placed on the back, and liquid crystal displays that combine a prism sheet for focusing light or a brightness-enhancing film that retroreflects specific polarizations to efficiently emit backlight light on the light source emission surface side can also be used.

[0154] Furthermore, in the head-up display system of the present invention, the image projector 2 used in the head-up display system preferably has a P-polarized component ratio of 51% or more and 100% or less in the emitted light, similar to the image projector 1. Similar to the image projector 1, the ratio of the P-polarized component in the light emitted from the image projector 2 is preferable to be higher, more preferably 90% or more, and even more preferably 99% or more, from the viewpoint of suppressing multiple images and improving image visibility when wearing polarized sunglasses. For the reasons stated above, there is no particular upper limit to the ratio of the P-polarized component in the light emitted from the image projector 2; theoretically, it can be 100%.

[0155] To increase the proportion of P-polarized light in the light of the image, it is preferable that the image projector 2 used in the head-up display of the present invention be retrofitted with a linear polarizer to control the direction of oscillation of the polarization of the light emitted from the image projector. In the case of an augmented reality type image projector that displays an image superimposed on a landscape seen through a projected image display member, which can be preferably used as the image projector 2, the optical path length is created inside the image projector by repeatedly reflecting light with a planar reflective mirror to increase the focal length of the projected image, and the image is emitted over a wide area by utilizing magnification with a concave mirror (curved mirror). However, the amount of S-polarized light tends to increase each time it passes through mirror reflection. Therefore, in such an embodiment, even if the light source of each image projector has a P-polarized component of 100%, the proportion of P-polarized light emitted from the image projector via the mirror will decrease from 100%. The S-polarized light component generated by this mirror reflection causes reflection on the surface of the projected image display member, and as a result, multiple images may be visible. To prevent the multiple images that occur through this mechanism, it is preferable to provide a linear polarizing plate at the light output portion of each projector to cut the S-polarized component, as this increases the proportion of P-polarized light in the image and makes the image projected onto the projection display member clearer. Furthermore, providing a linear polarizing plate at the light output portion of each projector also has the effect of reducing the amount of outdoor light (especially thermal rays) entering the inside of each projector, which is also preferable as it helps to prevent deterioration of the projector due to heat generation. Various linear polarizing plates exemplified in combination with the projector 1 can be used as the linear polarizing plate.

[0156] In the head-up display system of the present invention, when the region without the colored layer in the projected image display member is defined as the second region, it is preferable that the incident angle α(°) of light incident from the image projector 1 to the first region is greater than the incident angle β(°) of light incident from the image projector 2 to the second region. This point will be explained in more detail with reference to Figure 20, a schematic diagram of a head-up display system according to one embodiment of the present invention. The head-up display system in the embodiment shown in Figure 20 uses the projected image display member shown in Figure 3. In Figure 20, reference numeral 18 denotes the colored layer, reference numeral 19 denotes the first region, reference numeral 20 denotes the second region, reference numeral 1 denotes the projected image display member, reference numeral 35 denotes the image projector 1, reference numeral 36 denotes the image projector 2, reference numeral 37 denotes the optical path from the image projector 1 to the driver's line of sight, reference numeral 38 denotes the optical path from the image projector 2 to the driver's line of sight, reference numeral 39 denotes the incident angle α, and reference numeral 40 denotes the incident angle β.

[0157] In the head-up display system shown in Figure 20, in order to deliver the light emitted from each image projector installed on the dashboard to the driver's field of vision, considering the installation angle of the projected image display member 1 and the position of the colored layer 18, it is preferable to install the image projector 1 (reference numeral 35) further away from the driver and the image projector 2 (reference numeral 36) closer to the driver. Here, it is conceivable to install the first region 19 having the colored layer 18 on the upper part of the projected image display member, but it is extremely difficult to construct an optical path that specularly reflects the light of the image from the image projector on the dashboard to the driver's line of sight, and furthermore, actually viewing information such as speed display overhead would unnecessarily widen the range of movement of the driver's gaze, so it is not practical. In a design where the colored layer of the projected image display member 1 is positioned on the lower side, and images are projected from the image projectors 1 and 2 (reference numerals 35 and 36) into the first and second regions, respectively, the driver's line of sight will be lowered when viewing the first region of the projected image display member. Therefore, it is preferable that the relationship between the angle of incidence α (reference numeral 39) and the angle of incidence β (reference numeral 40) is such that angle of incidence β < angle of incidence α.

[0158] The angle of incidence here shall be determined at the center of the light illumination range of projectors 1 and 2. The center of the light illumination range refers to the intersection of the diagonals when the area on which the image is projected is enclosed by a quadrilateral region of the smallest area. Furthermore, if the projected image display member is planar, it shall be the angle between its surface and the direction of propagation of the light emitted from projectors 1 and 2. However, if the projected image display member is curved, it shall be the angle between the tangent surface at the center of the light illumination range of projectors 1 and 2 and the direction of propagation of the light emitted from projectors 1 and 2.

[0159] Furthermore, it is preferable that the head-up display system of the present invention satisfies the relationship between the incident angles α and β, which is 40° ≤ incident angle β < incident angle α ≤ 70°. If the image projectors 1 and 2 are set up so that the incident angles of the light of the image (incident angles α, β) satisfy the above relationship, when an image is projected with light that has a high ratio of P-polarization, the effect of the resin layer with an inclination angle is added, suppressing the multiple images generated on the surface of the projected image display member and making the main image by the light reflected by the P-wave reflector clearer. Of course, by bringing the incident angle closer to the Brewster angle, multiple images become less visible even without the inclination design of the resin layer, so it is more preferable that the incident angles α and β are 45° ≤ incident angle β < incident angle α ≤ 65°.

[0160] By setting the incident angle β to 40° or more, sufficient reflection from the P-wave reflector is obtained, and the P-polarized reflectance reflected from the transparent surface in the second region of the projected image display member is suppressed. As a result, the main reflected image becomes relatively clearer, making it less likely to be perceived as a multiple image. On the other hand, by setting the incident angle α to 70° or less, an optical path can be secured that allows the light of the image to reach the driver's eyes from the image projector 1 via the projected image display member. If the incident angle α is increased beyond this, the image reflectance reflected from the transparent surface increases, and the brightness of the main image reflected by the P-wave reflector also increases. However, the main image appears relatively darker, making it more likely to be perceived as a multiple image. Furthermore, considering the installation position of the image projector 1 and the direction of its light emission, it may be difficult to design the dashboard in a way that allows the image projector 1 to be positioned to reduce multiple images while ensuring visibility of the image from the observer's (driver's) line of sight. Since these incidence angles correspond to the incidence angle of light from the image projector, the condition 40° ≤ incidence angle β < incidence angle α ≤ 70° can be achieved by appropriately adjusting the positions of image projectors 1 and 2 and the angle of the projected image display member.

[0161] In the present invention, the head-up display preferably satisfies both TA(0°) ≤ 1% and RpA(α) ≥ 20% when point A is the center point of the image projection range in the first region of the projected image display device, TA(0°) is the average transmittance of the visible light region when incident at an incident angle of 0° to point A, the tangent surface at point A is the reflective surface, and linearly polarized light containing only the P-polarized component is incident along the incident surface including the orientation axis at point A at an incident angle θ to obtain the average reflectance at wavelengths of 400 to 700 nm, and RpA(θ) is obtained.

[0162] The method for determining point A will be explained in detail using the drawings. Figure 21 is a schematic diagram illustrating the image projection area and point A in the first region of the projection image display member of the head-up display system of the present invention, and the image projection area and point B in the second region. In Figure 21, reference numeral 19 denotes the first region, reference numeral 1 denotes the projection image display member, reference numeral 41 denotes the image display area in the first region, reference numeral 42 denotes point A, reference numeral 43 denotes the image display area in the second region, and reference numeral 44 denotes point B. For the image projected onto the first region, the image display area is defined by enclosing it with a rectangular frame having sides parallel to the reference line C of the projection image display member (not shown in Figure 21), as indicated by reference numeral 41 in Figure 21. Diagonals are drawn for this image display area, and the intersection of these lines is defined as point A (reference numeral 42). The reference line C of the projection image display member can be defined in the same way as defined in Figure 13. Point B, described later, can also be defined in the same way. If the projected image display member is curved, point A shall be determined by drawing the diagonal of the image display area along the curved surface.

[0163] The orientation axis direction at point A is determined using a phase difference measuring device (KOBRA-WPR) according to the measurement method (6) described below. Specifically, a straight line is drawn through point A and parallel to the y-axis (indicated by 6) (strictly speaking, it is not a straight line if the member is a curved surface, but since the test piece is usually small, it is interpreted as being equivalent to a straight line when considering the curvature). The projection image display member is cut out using the position corresponding to the boundary between the first and second regions as the center to create an evaluation sample. The orientation angle is measured on the transparent part of the evaluation sample using the phase difference measuring device, and the direction indicated by the obtained angle is defined as the orientation axis direction at point A. Strictly speaking, it is different from point A, but since the distance between point A and the boundary line between the first and second regions is not that far, the orientation axis direction at point A and the orientation axis direction at the measurement point can be interpreted as being the same.

[0164] In the head-up display system of the present invention, it is preferable that the average transmittance TA(0°) of visible light incident at point A at an incident angle of 0° satisfies TA(0°) ≤ 1%. One of the roles of the first region containing the colored layer is to protect the adhesive used when assembling the projected image display member to the vehicle from deterioration due to outdoor light. Furthermore, by providing a colored layer with low light transmittance, it is possible to improve the visibility of the projected image even in bright outdoor environments and to reduce the risk of multiple images being visible by blocking light that transmits toward the outermost layer on the outside of the vehicle of the projected image display member. In order to prevent deterioration of this adhesive, it is preferable to lower the light transmittance in the first region, and more preferably to 0.1% or less. TA(0°) in the first region can be achieved by changing the light transmittance of the colored layer, that is, by changing the concentration of pigments added to the colored layer, the combination of pigments, and the thickness of the colored layer.

[0165] When the average reflectance at wavelengths of 400 to 700 nm, obtained by incidenting linearly polarized light containing only P-polarized components at an incident angle θ along the incident plane including the orientation axis obtained above, is defined as RpA(θ), it is preferable that RpA(α) ≥ 20%. With this configuration, the image can be sufficiently projected by the reflective effect of the P-wave reflector of the projected image display member. Since the first region has a colored layer, the image can be clearly seen even under conditions where the reflectance of light from the image projector is low compared to the highly transparent second region. The upper limit of RpA(α) is theoretically 100% according to the spectral measurement method described later, but if RpA(α) is high, when the driver looks at the first region of the projected image display member, information from the area surrounding the image projector that projects the image may be reflected and projected, which may reduce the visibility of the image that is originally intended to be displayed. For this reason, from the above viewpoint, RpA(α) is preferably 20% to 35%. Furthermore, in order to suppress heat generation in the image projector during long-term operation and to ensure that the image is clearly visible even when the image projector emits low-luminance light, and that reflections are also suppressed, RpA(α) is more preferably 20% to 30%.

[0166] Furthermore, in order to set RpA(α) to 20% or more or within the above preferred range, it is preferable to use the aforementioned laminated film as the P-wave reflector constituting the projected image display member. Specifically, it is particularly effective to adjust the difference in refractive index perpendicular to the film surface (perpendicular refractive index) between the resin layer with the largest refractive index perpendicular to the film surface and the resin layer with the smallest refractive index perpendicular to the film surface, as well as the number of layers, among the multiple thermoplastic resin layers constituting the regularly arranged unit of the laminated film. More specifically, for the former, it is preferable to set the difference in refractive index perpendicular to the film surface to 0.02 or more and 0.08 or less. For the latter, RpA(α) can be increased by increasing the number of layers.

[0167] In the head-up display system of the present invention, when point B is the center point of the image projection range in the second region of the projected image display member, it is preferable that the angle between the intersection line of the plane containing the electric field vibration direction of the P-polarized component of the light emitted from the image projector 2 and the surface of the projected image display member, and the orientation axis at point B, is 0° to 10° or 80° to 90°. The electric field vibration direction of the P-polarized component can be determined by rotating the absorption axis direction of a linear polarizer with respect to the reflected image from a transparent member arranged so that the incident angle is 60°, and selecting the absorption axis direction that appears darkest. Designing the angle between the intersection line of the electric field vibration direction of the P-wave and the projected image display member and the orientation axis at point B to be 0° to 10° or 80° to 90° helps to suppress multiple images that occur when S-polarized light, which is generated due to a misalignment with the orientation axis of the P-wave reflector after the P-polarized light is incident on the projected image display member, is reflected at the outermost surface of the projected image display member.

[0168] Next, the manufacturing method of the projection image display member of the present invention (the projection image display member constituting the head-up display of the present invention) will be described using the case in which glass is used as the transparent member as an example. However, the manufacturing method of the projection image display member of the present invention is not limited to this example.

[0169] The following is an example of a method for manufacturing a laminated glass projection image display member when the aforementioned laminated film is used as a P-wave reflector. Transparent member 1 and transparent member 2 (both glass), resin layer 1 and resin layer 2, and laminated film (P-wave reflector) to be used in the projection image display member are prepared in the sizes necessary for lamination. If the transparent member is curved, the resin layer and laminated film are cut to a larger area than the transparent member. These materials are laminated in the order of transparent member 1 / resin layer 1 / laminated film / resin layer 2 / transparent member 2 to construct a laminated glass structure that can achieve the desired inclination angle. At this time, when the projection image display member is incorporated into a head-up display system, a colored layer is applied and fired in advance to form a colored layer at a position corresponding to the lower part of the mating surface on the inner surface of transparent member 2, which is opposite to the light incident surface, in accordance with the desired area on which the projection image display member will be projected. In general, laminated glass structures formed in this manner are created by bonding the laminated film and resin layer at a low temperature (pre-lamination process), and then bonding them to a support by applying pressure at a higher temperature (main bonding process).

[0170] While there are no particular limitations to the pre-lamination process, it is common to sandwich a laminated film between two resin layers and perform roll heat lamination at a temperature of +10 to 30°C above the glass transition temperature of the highest thermoplastic resin layer constituting the laminated film. If a thin film material of 150 μm or less is selected as the resin layer, wrinkles may form depending on the shape of the transparent component, potentially leading to a decrease in the appearance quality of the final projected image display component, such as bubbles and wrinkles. Therefore, it is possible to use laminated films and resin layers that have been pre-pressed together by heat roll lamination. The heat-pressure bonding temperature can be adjusted as appropriate depending on the material of the resin layer, but when using a material mainly composed of polybutylene butyrate, a temperature of 80°C to 140°C is preferably selected.

[0171] While there are no particular limitations on the method of the main bonding process after the pre-lamination process, it is common to bond the laminated glass structure in an autoclave (pressure-heated bonding furnace) at 140-150°C for 20-30 minutes under a pressure of 12-14 kg / cm2.

[0172] Furthermore, when a P-wave reflector is applied to the outermost surface as a component of a projected image display member, the resin layer and laminated film (P-wave reflector) are installed in a direction that shows the desired inclination angle, a transparent member (glass) of the same shape is laminated as a cover glass on the outermost surface of the projected image display member, and then heat-pressure bonding is performed under the above temperature conditions, and finally the cover glass is peeled off to obtain the desired projected image display member.

[0173] The second projection image display member of the present invention is a projection image display member comprising a transparent member, a resin layer, and a P-wave reflector, wherein two orthogonal lines are drawn on the surface of the projection image display member, passing through the center point C of the projection image display member and such that the shorter of the two lines is the shortest length, with the longer line being the x-axis and the shorter line being the y-axis, and the points located 50 mm inward from the end of the projection image display member on the x-axis and y-axis are designated as points x1, x2, y1, and y2, respectively, and the points x1, the center point C, and the point x2 The projection image display member satisfies the following conditions (1) to (3) simultaneously when the thickness of the resin layer increases or decreases in the order of, or in the order of point y1, the center point C, and point y2, and when the average transmittance of visible light incident at the center point C at an incident angle of 0° is T(0°), the tangent surface at the center point C is the reflective surface, and linearly polarized light containing only the P-polarization component is incident along the incident surface including the orientation axis at the center point C at an incident angle θ, and the average reflectance at wavelengths of 400 to 700 nm is Rp(θ). (1) T(0°)≧70% (2) Rp(60°)≧20% (3) Rp(20°)≦Rp(40°) <Rp(60°)。

[0174] The definitions of the transparent member, resin layer, and P-wave reflector constituting the second projection image display member of the present invention, and the method of determining the center point C, x-axis, y-axis, points x1, x2, y1, and y2, shall be considered to be the same as the definitions described in the description of the first projection image display member (parts common to the first projection image display member, including preferred ranges and embodiments, may be the same as those of the first projection image display member of the present invention). The second projection image display member of the present invention has a configuration in which the thickness of the resin layer increases or decreases in the order of point x1, the center point C, and point x2, or in the order of point y1, the center point C, and point y2. However, unlike the first projection image display member, it does not have a colored layer for projecting images, and the entire surface of the projection image display member must be a transparent area.

[0175] Unlike the first projection image display member, which is intended to project speed and hazard information onto the colored layer area of ​​the projection image display member, the second projection image display member has a wide transparent area, making it suitable for use in W-HUD and AR-HUD (augmented reality head-up display) systems that display navigation and other information in a clear, three-dimensional way by overlaying it onto the scenery outside the car window. In particular, AR-HUD can acquire information from outside the car using sensing technology and utilize images with different focal lengths to display lane-aligned route information, approach information such as the direction of movement of surrounding vehicles and people, and tourist information overlaid on the actual movement of the scenery outside the car window. In such display methods, it is necessary to overlay the image while keeping everything from the far distance to the ground near the car visible, so it is undesirable to use a configuration that may narrow the field of view, such as a colored layer. Therefore, the second projection image display member of the present invention, which does not use a colored layer as a projection display area, is necessary.

[0176] In addition, since the video will be widely projected onto the transparent video display area, the incident angle of the light emitted from the video projector to each display area will change according to the projection position. At this time, when it is designed such that the incident angle is near the Brewster angle, there is no influence of multiple images. On the other hand, in the projection part that does not satisfy the Brewster angle condition, the risk of generating multiple images increases. In particular, unlike the first projection image display member, since the entire projection area is transparent, there are two surfaces of the projection image display member where ghost images occur. Therefore, the light incident angle conditions for displaying the video without multiple images become narrower. Thus, in the area where the video is displayed under the incident angle conditions deviating from the Brewster angle, as a configuration in which the surfaces of the projection image display member are not parallel but slightly inclined, a configuration can be used as one aspect to prevent the ghost images from being visually recognized as multiple enhancement due to their overlap.

[0177] As an optical characteristic, for a second projection image display member suitable for such AR-HUD display, in order to sufficiently obtain the visibility of the scenery, it is necessary that the average transmittance T(0°) of visible light incident at an incident angle of 0° at the center point C of the projection image display member is 70% or more. Further, in order to reflect the video at an incident angle near the Brewster angle, by preferably using the P-wave reflector described in the description of the first projection image display member, as the projection image display member, with the tangent plane at the center point C as the reflection surface, linearly polarized light containing only the P-polarization component is incident at an incident angle of 60° along the incident plane including the orientation axis at the center point C, and it is necessary that the average reflectance Rp(60°) in the wavelength range of 400 to 700 nm is 20% or more. Also, generally, when the video light is projected as the P-polarization component under the incident angle conditions near the Brewster angle, in order to prevent the reflectance from becoming low and the visibility of the display image from deteriorating, as a preferably used P-wave reflector and as the projection image display member equipped with it, it is necessary to satisfy the reflectance relational expression of Rp(20°) ≤ Rp(40°) < Rp(60°). These optical characteristics can be realized by satisfying the respective constituent requirements of the transparent member and the P-wave reflector constituting the projection image display member, and the achievement requirements as manufacturing conditions, as described in the explanation of the first projection.

[0178] In the second projection image display member of the present invention, when linearly polarized light containing only the P-polarization component is incident on the center point C2 at an incident angle of 60°, with the tangent surface at the center point C of the projection image display member serving as the reflective surface, it is preferable that the change in average reflectance at wavelengths of 400 to 700 nm when the projection image display member is rotated in-plane from 0° to 90° around the center point C, with the direction of the incident surface including the orientation axis being 0°, is 0% or more and 25% or less.

[0179] When displaying images over a wide area, the image may be viewed not only in the direction directly in front of the viewer's eyes, but also to the side and at an angle. Therefore, it is desirable that the projection image display member maintains consistent display properties, such as multiple images and brightness, when the image is viewed at any azimuth angle. To achieve these characteristics, it is preferable to use the aforementioned biaxially stretched laminated film as the P-wave reflector constituting the projection image display member, rather than a uniaxially stretched polarizing reflective film. In particular, it is preferable to use a film that has thermoplastic resin layers with different refractive indices, and whose biaxial stretching process conditions are controlled so that the difference in refractive index between the orientation axis direction and the direction perpendicular to the orientation axis direction of the crystalline thermoplastic resin located on the outermost layer of the laminated structure is 0.05 or less. The lower limit of the change in average reflectance at wavelengths of 400 to 700 nm is set to 0%, but considering the orientation angle unevenness within the film plane due to the bowing phenomenon in the biaxial stretching manufacturing process, it is preferable that the laminated film applied as the P-wave reflector is designed so that the stretching ratio is high in a specific direction, resulting in less change in the orientation axis direction in the width direction, and the average reflectance of the film differs slightly in the in-plane rotation direction. Specifically, the reflectance change is preferably 5% to 20%, and more preferably 10% to 20%. Such desirable reflectance change conditions can be achieved by using the stretching process conditions described in the section on the method for manufacturing the laminated film of the present invention. [Examples]

[0180] The present invention will be described below in reference to the examples, but the present invention is not limited to the embodiments shown in these examples. The characteristics and effects were measured and evaluated using the following methods.

[0181] (Methods for measuring characteristics and evaluating effects) The method for measuring the characteristics and evaluating the effects in this invention is as follows. (1) Differential scanning calorimetry (DSC) A differential scanning calorimeter EXSTAR DSC6220 manufactured by Hitachi High-Technologies Corporation was used for the measurements. Measurements and temperature readings were performed in accordance with JIS-K-7122 (1987). Specifically, when approximately 5 mg of the sample was heated from 25°C (room temperature) to 300°C at a rate of 10°C / min on an aluminum tray, the microcrystalline melting temperature, which shows a small endothermic peak different from the melting point at a temperature higher than the glass transition temperature Tg (°C) at the intersection of the baseline and the tangent at the inflection point of the step transition portion, was read as the heat treatment temperature of the laminated film. Furthermore, after rapid cooling with liquid nitrogen after heating, the area of ​​the endothermic peak (melting point) observed at the highest temperature when heating was performed again under the same conditions was determined and defined as the enthalpy of fusion Tm (J / g).

[0182] (2) Lamination configuration of laminated film as a P-wave reflector The layer structure of the laminated film used as a P-wave reflector was identified and measured by transmission electron microscopy (TEM) observation of samples thinned using an ultramicrotome. Specifically, a JEM-1400 Plus transmission electron microscope (manufactured by JEOL Ltd.) was used to observe the cross-section of the laminated film (in the thickness direction, i.e., the cross-section perpendicular to the film surface) under an acceleration voltage of 100kV. By obtaining cross-sectional images, the layer structure (number of layers, regular arrangement, layer thickness distribution) and the thickness of each layer were measured. In addition, staining techniques using electron staining agents (such as RuO4) were employed during cross-sectional observation to obtain a large contrast difference between each layer. Furthermore, depending on the thickness of each layer, observations were performed at a direct magnification of 40,000x for thin film layers with a thickness of less than 100nm, at a direct magnification of 20,000x for thin film layers with a thickness of 100nm or more but less than 500nm, and at 1,000x to 10,000x depending on the thickness for layers with a thickness of 500nm or more. By analyzing the thickness of each layer using the method described in (3) Layer Interface (Contrast Difference), the number of layers, the regular arrangement (layer structure), the thickness of each layer, and the distribution of layer thicknesses were determined.

[0183] (3) Layer interface of laminated film as a P-wave reflector (contrast difference) (2) The cross-sectional images obtained from the transmission electron microscope observation were converted to compressed image file (JPEG) format, and position-luminance data was acquired by line profiling using MediaCybernetics ImagePro-10 along the thickness direction of the laminated film. Subsequently, a 5-point moving average was applied to the profile obtained by plotting the relationship between position and luminance using spreadsheet software (Microsoft Excel® 2016). The averaging process was performed by applying the luminance average to five consecutive measurement positions, changing the position one point at a time, and repeating the same calculation to obtain the averaged position-luminance profile. In the obtained averaged position-luminance profile, the position enclosed by inflection points where the slope changes from positive to negative or from negative to positive was determined to be a single layer. For each layer obtained using this method, position-luminance data was then acquired in the planar direction of the laminated film (perpendicular to the thickness direction). After calculating the average value and standard deviation of the luminance obtained for each layer, if the difference between the average values ​​of the luminances of two adjacent layers was greater than either of the standard deviations of the luminances of the adjacent thermoplastic resin layers, these two adjacent layers were determined to be different. Furthermore, the difference in position (distance) between the inflection points was calculated as the layer thickness of each layer.

[0184] (4) Spectroscopic measurement (average transmittance of visible light with normal incidence; T2 (0°), TA (0°), T (0°), and transmittance of transparent material) A sample of a transparent material, projection image display material, or P-wave reflector to be measured was cut into a 9cm square to include the predetermined measurement position. A variable-angle reflection unit and a Gran Taylor polarizer attached to a Hitachi High-Tech Science Co., Ltd. spectrophotometer (U-4100 Spectrophotometer) were used. The scale on the sample incidence side unit was set to 0°, and the scale on the integrating sphere unit side was set to 180°. Transmission spectral measurements were taken in the wavelength range of 395nm to 805nm under both P-wave and S-wave irradiation conditions. The P-wave and S-wave measurement results were averaged to obtain the desired transmission spectral spectrum. For the measurements, the scan speed was set to 600nm / min and the sampling pitch to 1nm. For the transmission spectral data in the wavelength range of 395nm to 805nm, 10 consecutive data points were averaged to obtain spectral data. Subsequently, the average value for wavelengths from 400nm to 800nm ​​was calculated to obtain the average visible light transmittance.

[0185] (5) Spectral spectrum measurement (P wave, 400-700nm average reflectance, measurement angle θ; Rp2(θ), Rp(θ), RpA(θ), RpB(θ)) For the projection image display member or P-wave reflector sample containing each point extracted in section (4) above, an angle-variable reflection unit and a Gran Taylor polarizer attached to a Hitachi High-Tech Science Co., Ltd. spectrophotometer (U-4100 Spectrophotometer) were mounted, and the reflectance when P-waves were irradiated in the wavelength range of 395 to 705 nm at an incident angle θ was measured at a scan speed of 600 nm / min and a sampling pitch of 1 nm. The obtained reflection spectrum data was averaged from 10 consecutive points, and the average P-wave reflectance in the wavelength range of 400 nm to 700 nm at an incident angle θ was calculated. The tilt direction for incident light was determined by measuring the orientation axis direction of the multilayer laminated film and projection image display member according to (6) or (7) below, and tilting in the direction along the orientation axis.

[0186] (6) Orientation axis When the P-wave reflector could be detached from the second or first region of the projected image display member, the orientation axis direction was measured using a phase difference measuring device (KOBRA-WPR) manufactured by Oji Instruments Co., Ltd. Measurement samples of the projected image display member were cut from predetermined locations into 10cm squares and placed on a large sample set stand at the bottom of the device. At this time, the reference axis C, which corresponds to the intersection line with the horizontal plane when the projected image display member is installed for a head-up display, was set to coincide with the angle 0° defined by this measuring device. Subsequently, the orientation angle from the angle 0° defined by this measuring device was analyzed for the installed measurement samples. The orientation angle was measured in -90° to 90° range. The variation in orientation angle was analyzed at five points: the center point of the measurement sample and the midpoint between the center point and the ends in the long / short side directions. The variation in orientation angle was defined as the angle between the two largest orientation axes among the five predetermined orientation angles. If the variation in orientation angles at the five points spans an axial direction corresponding to ±90°, the smaller of the angle between the orientation axis direction showing the smallest positive value and the orientation axis direction showing the largest negative value among the orientation axes at the five points was adopted. The orientation axis direction was defined as the linear direction extending in the opposite direction to the direction indicated by the orientation angle relative to the measurement point.

[0187] (7) Refractive index evaluation The in-plane average refractive index of the outermost layer of the P-wave reflector was determined by measuring the refractive index in each direction under the following conditions using a SAIRON TECHNOLOGY, INC. "SPA-4000" and calculating the in-plane average refractive index and perpendicular refractive index as follows: The in-plane average refractive index was defined as the average of the refractive index in the direction of the orientation axis of the P-wave reflector and the refractive index in the direction perpendicular to the orientation axis in the plane. The perpendicular refractive index was defined as the average of the refractive index in the direction perpendicular to the orientation axis of the P-wave reflector and the refractive index in the direction perpendicular to the direction perpendicular to the orientation axis. The orientation axis was determined by reading the orientation angle obtained in advance by the method described in (6), and was defined as the direction passing through the measurement point and indicated by the orientation angle. <Measurement conditions> Measurement modes: TE mode (for in-plane refractive index measurement), TM mode (for perpendicular refractive index measurement) Laser: Wavelength 632.8nm Prism: GGG Prism.

[0188] (8) Electron energy loss spectroscopy (EELS measurement) Before measurement, the orientation axis of the laminated film used as a P-wave reflector was determined by the method described in (6) or (7). Cross-sectional (thickness-direction cross-section) samples of the target object were prepared along the orientation axis parallel to the target object using an ultramicrotome ultrathin sectioning method, and planar cross-sectional samples of each layer were prepared so as to be approximately parallel to the layer direction of the laminated film. The dielectric constant of the prepared cross-sectional / planar cross-sectional samples was measured using a JEOL ARM200F atomic-resolution analytical electron microscope. Specifically, HAADF-STEM (High Angle Annular Dark-Field Scanning Transmission Electron Microscopy) images were acquired with an acceleration voltage of 80kV and a beam spot size of 0.2mmφ. Then, multi-point analysis (60×60 pixels, 20nm / pixel) was performed on the target layer at 50msec to obtain data on energy loss and electron beam intensity. The same procedure was performed at three points for each thermoplastic resin layer in the laminated film to obtain data with an improved signal-to-noise ratio. From the obtained spectra, background correction due to elastic scattering and removal of multiple scattering effects were performed, and then the dielectric function of each layer was calculated using the Kramers-Kronig transform shown in equation (3). The integration range for the Kramers-Kronig transform was set to 0 to 200 eV. Based on the dielectric function in equation (3), the real and imaginary parts of the dielectric constant were calculated from equations (4) and (5), respectively, and then the dielectric constant was calculated from equation (6), which is the square root of the sum of the squares of these parts. Using the above method, the dielectric constant at a loss energy of 2.5 eV for each thermoplastic resin layer was calculated and compared. In equations (3) to (6), Re is the real part, Im is the imaginary part, ε is the dielectric constant (mean value), ε(ω) is the dielectric function, ε1 is the real part of the dielectric constant, ε2 is the imaginary part of the dielectric constant, and ω and ω' are the angular frequencies, respectively.

[0189]

number

[0190]

number

[0191]

number

[0192]

number

[0193] According to Maxwell's electromagnetic theory, in non-magnetic materials that absorb little light, such as thermoplastic resins suitable for forming the thermoplastic resin layers constituting the laminated film of the present invention, the dielectric constant is generally equal to the square of the refractive index. Therefore, it is possible to estimate the refractive index from the dielectric constant of the thermoplastic resin layer. The refractive index of the thermoplastic resin layer not located on the outermost surface of the laminated film was calculated proportionally using the relative ratio of the in-plane / orthoplane refractive index of each layer obtained from EELS measurements, with the absolute value obtained in section (7) as the reference value for the thermoplastic resin located on the outermost surface.

[0194] (9) Fabrication of projection image display component (P-wave reflector embedded type) As transparent components, transparent components described in Tables 2 and 3, measuring approximately 500 mm in length and 700 mm in width, were prepared. One of the transparent components was prepared by coating and firing a black ceramic printed layer containing a Bi compound on the lower 150 mm portion along the horizontal direction. The laminated film used as the P-wave reflector was prepared by cutting it so that the roll transport (longitudinal direction) was 500 mm and the film width direction was 700 mm. Resin layers 1 and 2 were also prepared by cutting them so that the roll transport (longitudinal direction) was 500 mm. A glass laminate was constructed by laminating the transparent component / resin layer 2 / P-wave reflector / resin layer 1 / transparent component (with a black ceramic printed layer on the inside) in that order. The resulting glass laminate was placed in a rubber vacuum bag and held at 60°C for 30 minutes under reduced pressure suction, and then held at 100°C for another 60 minutes for preliminary bonding. The pre-compressed glass laminate was placed in an autoclave and processed under high temperature and pressure of 140°C and 13 atmospheres for 30 minutes to obtain a laminated glass type (interpolated configuration) projection image display member.

[0195] (10) Creation of projected image display component (P-wave reflector, internal mounting type) Transparent members as described in Tables 2 and 3, with the sizes described in (9), were prepared, and a glass laminate was constructed by laminating the transparent member / resin layer 2 / transparent member (with a black ceramic printed layer on the outside) in that order. Laminated glass was then produced from the obtained glass laminate using the same method as described in (9). Next, a flat transparent glass plate measuring 150 mm in length x 700 mm in width x 2 mm in thickness, a P-wave reflector cut to a length of 500 mm in the roll transport direction and 700 mm in the film width direction, and resin layer 1 were prepared. Resin layer 1, P-wave reflector, and flat transparent glass were stacked on top of the previously prepared laminated glass in that order, overlapping the side of the laminated glass where the colored layer is applied, to form a second glass laminate, and heat and pressure treatment was performed using the same method as described in (9). Finally, the 150 mm x 700 mm flat transparent glass laminated on the outermost side was removed to obtain the desired projection image display member.

[0196] (11) Evaluation in a head-up display configuration (Area 1) The projected image display member prepared in (9) or (10) was installed horizontally with the colored layer facing downwards, and positioned so that light from the projector was incident on the recessed side of the projected image display member. Furthermore, the projected image display member was installed relative to the projector at the incident angles shown in Tables 4 and 5 (for example, if θ=60°, light emitted perpendicularly from the light source will have an incident angle of 60° with respect to the surface of the projected image display member and the downward normal direction). One of the projector 1 to 3 was installed so that light was incident on the first region of the projected image display member at the incident angles shown in Tables 4 to 5, and the "image visibility," "multiple images," and "appearance" were evaluated according to the following criteria when viewed from a distance of 1m from the image display position at the same horizontal plane height as the image projected in the first region. Note that evaluation S was the best, and the evaluations were in the order of S, A, B (or B1 / B2), C, with N being judged as poor.

[0197] (Image projector used) Image projector 1: A liquid crystal display with a P-polarization emission coefficient of 75%, equipped with a light source having the emission spectrum shown in Figure 18. The projector was installed so that the angle between the intersection line (direction of electric field vibration) of the incident plane of P-polarization and the projection image display member, and the orientation axis of the projection image display member, is as shown in Tables 4 and 5. Image Projector 2: A liquid crystal display capable of projecting an image with a P-polarization ratio of 99% or more of the emitted light by installing a wire grid type linear polarizer in the image emission area of ​​Image Projector 1, such that the angle between the field vibration direction of P-polarized light (when the projected image display member is the reflective surface) and the orientation axis of the projected image display member is as shown in Tables 4 and 5, and the transmission axis of the polarizer coincides with the orientation axis of the projected image display member. Image projector 3: A liquid crystal display equipped with a light source having the emission spectrum shown in Figure 19, with a wire grid type linear polarizer in the image emission range, and positioned so that the transmission axis of the polarizer coincides with the orientation axis of the projection image display member, such that the angle between the electric field vibration direction of the P-polarized light and the orientation axis of the projection image display member is as described in Tables 4 and 5, when the projection image display member is the reflective surface. This enables the projection of an image with a P-polarization ratio of 99% or more.

[0198] (Image brightness) S: The image was clearly visible in a sunny outdoor environment (approximately 100,000 lux). A: In a sunny outdoor environment (around 100,000 lux), the image was somewhat dark, but by setting the projector's light output to 70% or higher, the image could be clearly seen. B1: Even when the projector's light output was set to 100% (maximum), the image brightness was poor in a sunny outdoor environment (approximately 100,000 lux), but in a nighttime environment (approximately 500 lux), the image could be clearly seen even with reduced output. B2: While there were conditions where the image was difficult to see depending on the viewing angle, it possessed characteristics sufficient for practical use as a head-up display. N: Regardless of the ambient brightness, even with the projector's light output set to maximum, the image could not be clearly seen, making it unsuitable for head-up displays.

[0199] (multiple images) S: The image was not blurry, and the displayed image was clearly visible. A: Multiple images can be observed if you look closely, but this has virtually no practical impact. B: Although multiple images could be recognized without close observation, it did not impair the visibility of the image, and there were no practical problems. N: Multiple images were strongly perceived, making it unsuitable for head-up displays.

[0200] (exterior) S: There was no reflection, and only the projected image was clearly visible. A: Reflections are weak, and the image is clearly visible, so there are no practical problems. However, depending on the viewing angle, there were some display inconsistencies such as uneven color and brightness, or areas that appeared weaker. B: While not a practical problem, the image projector on the dashboard was slightly obscured by reflections of surrounding information, resulting in a slight decrease in visibility. N: The projector on the dashboard was unusable as a head-up display because it strongly reflected information around it, or because it exhibited significant color and brightness unevenness.

[0201] (12) Evaluation in head-up display configuration (second region; transparent region) For the projected image display member installed by the method described in (11), the image projector 4 or 5 was installed so as to be incident on the second area of ​​the projected image display member at the incident angles shown in Tables 4 and 5. The "image visibility," "multiple images," and "appearance" were evaluated according to the following criteria when viewed from 1 m away from the image display position at the same horizontal plane height as the image, changing the viewing angle from left to right. At this time, the incident angle of the projected image display device was adjusted so that the image could be seen from the horizontal plane at a predetermined incident angle. Evaluation S was the best, followed by S, A, B (or B1 / B2), C in order of good evaluation, and N was judged to be poor.

[0202] (Image projector used) Image Projector 4: An augmented reality liquid crystal display capable of projecting an image with a focal length of 2m and a P-polarization ratio of 70%, equipped with a light source having the emission spectrum shown in Figure 18 inside the housing, a reflector, and a concave mirror. The angle between the intersection line (direction of electric field vibration) of the incident plane of P-polarization and the projection image display member and the orientation axis of the projection image display member was set as shown in Tables 4 and 5. Image projector 5: An augmented reality liquid crystal display capable of projecting images with a P-polarization ratio of 99% or more of the emitted light, by installing a wire grid type linear polarizing plate at the output port of image projector 4, such that the angle between the field vibration direction of P-polarized light (when the projected image display member is the reflective surface) and the orientation axis of the projected image display member is as shown in Tables 4 and 5, and the transmission axis of the polarizing plate is aligned with the orientation axis of the projected image display member.

[0203] (Image brightness) S: The image was clearly visible under any external lighting conditions. A: In a sunny outdoor environment (around 100,000 lux), the image brightness was somewhat dim, but it was visible when the display's brightness was set to a safe and usable output. B1: Even with the display brightness set to maximum output, the image brightness was still poor in a daytime environment simulating bright sunshine, but the image was clearly visible in a dark environment simulating nighttime (500 lux). B2: While there were conditions where the image was difficult to see depending on the viewing angle, it possessed characteristics sufficient for practical use as a head-up display. N: Regardless of the brightness of the external environment, the image was not clearly visible, making it unsuitable for head-up displays.

[0204] (multiple images) S: The image was not blurry, and the displayed image was clearly visible. A: Multiple images can be observed if you look closely, but this has virtually no practical impact. B: Although multiple images could be recognized without close observation, it did not impair the visibility of the image, and there were no practical problems. C: Ghosting was observed in dark environments, but it was usable to some extent during the day or in bright environments. N: Multiple images were strongly and clearly perceived, making it unsuitable for head-up displays.

[0205] (exterior) S: There was no reflection, and the visibility of the scenery as a window pane was excellent. A: There was some reflection of the dashboard area on the window glass, but it was at the same level as before, and the visibility of the scenery was sufficient. B: Reflections around the dashboard were somewhat strong, especially noticeable in dark environments, but it didn't pose any practical problems. N: The image around the dashboard was strongly reflected, impairing the visibility of the scenery through the window glass.

[0206] (13) Temperature rise of the dashboard Each projected image display member prepared in (9) or (10) was installed at the same angle as the evaluation conditions in (12), and two thick black colored high-quality cardboard sheets were placed in the same position as the image projector. A thermocouple was attached between the two black cardboard sheets, and artificial sunlight (XC-500E manufactured by Seric Co., Ltd.) was directed from directly above the black cardboard sheets, through the projected image display members, at an illuminance of 1000 mW / m². 2 The thermocouple was irradiated, and the temperature indicated after 30 minutes was measured and reflected according to the following criteria. S: The thermocouple temperature was below 40°C, indicating a sufficient level of heat shielding effect. A: The thermocouple temperature was in the range of 40° to 50°C, which indicates that there is a heat shielding effect. B: The thermocouple temperature was in the range of 50-60°C, indicating a weak heat shielding effect, but it was still at a usable level. C: The thermocouple temperature exceeded 60°C, raising concerns about the risk of HUD malfunction and deterioration of the in-car environment.

[0207] The thermoplastic resin, water-based coating material X, and adhesive layer used in the examples and comparative examples of the present invention will be described below. Note that the copolymerization amounts of the polyester resins described herein represent the copolymerization amounts relative to 100 mol% of the acid component and 100 mol% of the diol component.

[0208] <Thermoplastic resin> Resin 1: A crystalline homopolyethylene terephthalate resin exhibiting a glass transition temperature of 78°C, a melting point of 254°C, and a melting enthalpy of 40 J / g. Resin 2: An amorphous polyethylene naphthalate resin exhibiting a glass transition temperature of 80°C, copolymerized with 30 mol% isophthalic acid relative to the total acid component and 4 mol% polyethylene glycol with a molecular weight of 400 relative to the total diol component. Resin 3: An amorphous polyethylene terephthalate resin copolymerized with 25 mol% naphthalenedicarboxylic acid, exhibiting a glass transition temperature of 90°C.

[0209] <Water-based paint X> A material was prepared by mixing polyester resin 1 (100 parts by mass), reactive compound 1 (30 parts by mass), and reactive compound 2 (30 parts by mass) as shown below. To this material, 0.5 parts by mass of silica colloidal particles with a particle size of 100 nm were added to 100 parts by mass of the binder resin, which is the mixture of the resin and the compounds. After adjusting the solid content concentration with water as the solvent to 5 parts by mass, 0.03 parts by mass of surfactant was added to 100 parts by mass of the total water and mixed to obtain a paint composition. Polyester resin 1: An aqueous dispersion of polyester resin having the following copolymer composition was obtained by the following procedure. The following copolymer components and 0.1 parts of potassium titanium oxalate as a catalyst were added to a reactor, and the temperature was raised to 200°C while stirring under atmospheric pressure and a nitrogen atmosphere. Next, the reaction temperature was gradually raised to 250°C over 4 hours to complete the transesterification reaction. 15 parts by mass of this polyester resin and 85 parts by mass of water were added to a dissolution tank and dispersed under stirring at a temperature of 80-95°C for 2 hours to obtain a 15% aqueous dispersion of polyester resin. This was designated as polyester resin 1. (Copolymer composition) • Dicarboxylic acid components 2,6-Dimethyl naphthalenedicarboxylate: 88 mol% Dimethyl sodium 5-sulfoisophthalate: 12 mol% • Diol components Compound obtained by adding 2 moles of ethylene oxide to 1 mole of bisphenol S: 86 mole% 1,3-Propanediol: 14 mol% Reactive compound 1: Carbodiimide aqueous crosslinking agent (Nisshinbo Chemical Co., Ltd. "Carbodilite" (registered trademark) V-04) Reactive compound 2: Oxazoline-containing polymer aqueous dispersion ("Epocross" (registered trademark) WS-500, manufactured by Nippon Shokubai Co., Ltd.).

[0210] <Resin layer> Resin layer A: A resin layer made of polyvinyl butyrate with a thinnest point of 380 μm and exhibiting a linear gradient thickness with a slope angle of 0.15 mrad. Resin layer B: A resin layer made of polyvinyl butyral with a certain thickness of 380 μm Resin layer C: A resin layer made of polyvinyl butyral, where the thinnest part is 380 μm, the inclination angles are different with the 150 mm position as the boundary, the inclination angle of the first stage up to that position is 0.15 mrad, and the inclination angle of the second stage is 0.3 mrad, showing a linear inclined thickness respectively Resin layer D: A resin layer made of polyvinyl butyral showing the same inclined thickness as resin layer A and containing 0.6% by mass of ITO (tin-doped indium oxide particles) Resin layer E: A resin layer made of polyvinyl butyral showing the same inclined thickness as resin layer C and containing 0.6% by mass of ITO Resin layer F: A resin layer made of polyvinyl butyral where the thinnest part is 380 μm, showing a linear inclined thickness with an inclination angle of 0.08 mrad Resin layer G: A resin layer made of polyvinyl butyral where the thinnest part is 380 μm, showing a linear inclined thickness with an inclination angle of 0.30 mrad.

[0211] <Transparent member> Transparent member 1: Transparent float glass with a length of 500 mm × a width of 700 mm × a thickness of 2.1 mm Transparent member 2: Transparent float glass with a length of 500 mm × a width of 700 mm × a thickness of 1.4 mm.

[0212] <P-wave reflector·layered film 1> Resin 1 and Resin 2 were used as the thermoplastic resins constituting layers A and B, respectively. Each of the prepared thermoplastic resins was separately fed into two twin-screw extruders in pellet form and melted and kneaded at 280°C. The kneading conditions were set so that the screw rotation speed was 0.7 relative to the discharge volume. Next, after removing foreign matter and other contaminants through seven FSS-type leaf disc filters, the mixtures were weighed using a gear pump and merged in a feed block with 801 slits heated to 280°C. This formed an 801-layer molten laminate with a regular arrangement in which layers A and B are alternately arranged in the thickness direction (layer A is the outermost layer on both sides), and a four-stage gradient structure in which the layer thickness distribution increases monotonically from the outermost layer on one side, decreases monotonically, increases monotonically, and decreases monotonically. In addition, thick film layers with the same thickness as the outermost layer were provided at intermediate layers corresponding to the boundaries of the monotonically increasing / decreasing layers (the 201st, 401st, and 601st layers counting from any outermost surface). Subsequently, the molten laminate that passed through the feed block was supplied to a T-die and formed into a sheet. Then, while applying an electrostatic voltage of 8kV with a wire, it was rapidly cooled and solidified on a casting drum where the surface temperature was maintained at 25°C to obtain a laminated cast sheet. The obtained laminated cast sheet was heated in a group of rolls set to 70-85°C, and then stretched 3.3 times in the longitudinal direction (longitudinal stretching) over a stretching section length of 100 mm while rapidly heating both sides of the film with a radiation heater, and then cooled. Next, both sides of the obtained uniaxially oriented film were subjected to corona discharge treatment in air to set its wetting tension to 55 mN / m, and then both sides were coated with a water-based coating agent X using #4 metabar (hereafter, "coating" means the above), forming a transparent, smooth, and easily adhesive layer. Furthermore, this uniaxially oriented film was guided to a tenter by gripping both ends in the width direction with multiple clips, preheated with hot air at 90°C, and then stretched 3.5 times in the width direction (transverse stretching) at a temperature of 100°C. Immediately after transverse stretching, the biaxially oriented film was heat-set with hot air at 190°C, and after a cooling process at a cooling temperature of 100°C in which a 2% relaxation treatment was applied in the width direction, it was slowly cooled to room temperature and wound up. Here, no further stretching was performed during heat-set in the width direction stretching, nor during the process of slowly cooling to room temperature. The evaluation results of the P-wave reflector (laminated film 1) obtained in this way are shown in Table 1.

[0213] <P-wave reflector laminated film 2 to 7> A laminated film was obtained in the same manner as laminated film 1, except that the resin and film-forming conditions of each layer were changed as shown in Table 1. The heat treatment draw ratio in the width direction was adjusted so that the clip-to-clip distance before and after the room with the highest heat treatment temperature linearly expanded at a predetermined ratio within the room, and the cooling draw ratio was adjusted so that the clip-to-clip distance linearly expanded at a predetermined ratio within the first room in the cooling process. Also, the thickness of the laminated film was adjusted by the take-up speed of the casting drum. The evaluation results of the obtained laminated films (laminated films 2 to 7) are shown in Table 1.

[0214] <Single-layer film> Resin 1 was used as the thermoplastic resin. Resin 1 was melted at 280 °C in an extruder, and after removing foreign substances etc. through 5 FSS type leaf disk filters, the molten resin was supplied to a T-die. After the molten resin was formed into a sheet and discharged by the T-die, while applying an electrostatic charging voltage of 8 kV with a wire, the molten sheet-like material was rapidly cooled and solidified on a casting drum maintained at a surface temperature of 25 °C to obtain an unstretched film. This unstretched film was stretched in the longitudinal direction at a temperature of 90 °C and a draw ratio of 3.3 times to obtain a uniaxially stretched single-layer film, and then corona discharge treatment was performed on both sides in air and aqueous coating agent X was applied in the same manner as in the production of multilayer laminated film 1. Then, the uniaxially stretched single-layer film was gripped at both ends in the width direction with a plurality of clips and guided to a tenter, and stretched in the width direction at a preheating temperature of 90 °C, a stretching temperature of 100 °C, and a draw ratio of 3.5 times. At this time, the clip gap was set so that the film was stretched at a uniform speed along the flow of film conveyance in the stretching process, and the maximum stretching speed was 9% / sec. Then, the film was passed through an intermediate region adjusted to 160 °C and heat-treated at 230 °C. At this time, no post-drawing was performed in the heat treatment process. Then, 3% width relaxation was performed and cooled at 100 °C to obtain a single-layer film with a thickness of 50 μm. The thickness of the single-layer film was adjusted by the take-up speed of the casting drum. The evaluation results of the single-layer film are shown in Table 1.

[0215]

Table 1

[0216] (Examples 1 to 17, Comparative Examples 1, 2) As shown in Tables 2 and 3, using the P-wave reflector, resin layers 1 and 2, and transparent members 1 and 2, the colored layer and the position of the P-wave reflector were provided at predetermined positions, and a projection image display member was produced as described in (10) and (11) above. The evaluation results of the optical characteristics of the obtained projection image display members are shown in Tables 2 and 3.

[0217]

Table 2

[0218]

Table 3

[0219] (Examples 18 to 43, Comparative Examples 3, 4) Using the projection image display members described in Tables 4 and 5 and projectors 1 to 5, after arranging them to meet the incident angle conditions described in Tables 4 and 5, a head-up display system with the configuration shown in (12) and (13) above was constructed. The evaluation results of the optical characteristics of the projection image display members and the HUD display performance evaluation results under the installed configuration requirements are shown in Tables 4 and 5 respectively.

[0220]

Table 4

[0221]

Table 5

Industrial Applicability

[0222] The present invention provides a projection image display member capable of clearly displaying images in multiple areas, and a head-up display system using the projection image display member of the present invention as a screen material. Because the projection image display member and head-up display system of the present invention have the above features, they are particularly suitable for use as a slope head-up display and a panoramic head-up display in transportation vehicles such as cars, railways, aircraft, and ships, whether they are human-operated or unmanned transportation vehicles carrying passengers, with the aim of minimizing eye movement for drivers and passengers and allowing them to instantly grasp speed displays, navigation information, etc., while viewing the projection image display member. [Explanation of Symbols]

[0223] 1: Projection image display member 2: Center point C 3:x-axis 4: Point x1 5: Point x2 6: y-axis 7: Point y1 8: Point y² 9: Horizontal plane 10: Image projector 11: Observer (Driver) 12: The optical path of the image from the projector to the observer's line of sight. 13: Transparent component 1 14: Resin layer 1 15:P wave reflector 16: Resin layer 2 17: Transparent component 2 18: Colored layer 19:First area 20:Second area 21: First surface portion of the maximum thickness portion and the minimum thickness portion 22: Second surface portion of the maximum thickness portion and the minimum thickness portion 23: First tilt angle 24: Second tilt angle 25: Point y3 26: Center point C2 27: Reference axis C 28: Tangent surface at point C2 29: Orientation axis at point C2 30: The angle between the orientation axis and the reference axis C at point C2 (orientation angle) 31: Spectrum showing the relationship between depth in the thickness direction and contrast (gray level) change in a laminated film with a regular arrangement. 32: Thickness of layer A 33: Thickness of layer B 34: Thickness of the C layer 35: Image projector 1 36: Image Projector 2 37: Light path from image projector 1 to the driver's line of sight 38: Light path from image projector 2 to the driver's line of sight 39: Incident angle α 40: Incident angle β 41: Video display area in the first region 42: Center point A 43: Video display area in the second region 44: Center point B

Claims

1. A projection image display member comprising a transparent member, a resin layer, and a P-wave reflector, and further having a colored layer in part, wherein when two orthogonal lines are drawn on the surface of the projection image display member passing through the center point C of the projection image display member and the shorter of the two lines being the shortest, with the longer line being the x-axis and the shorter line being the y-axis, and the points located 50 mm inward from the end of the projection image display member on the x-axis and y-axis are designated as points x1, x2, y1, and y2, respectively, the thickness of the resin layer increases or decreases in the order of point x1, the center point C, and point x2, or in the order of point y1, the center point C, and point y2.

2. The projection image display member according to claim 1, having a configuration in which a transparent member 1, a resin layer 1, the P-wave reflector, a resin layer 2, and a transparent member 2 are laminated in that order, the colored layer is laminated in a portion between the transparent member 2 and the resin layer 2, and the thickness of the resin layer 1 increases or decreases in the order of point x1, the center point C, and point x2, or in the order of point y1, the center point C, and point y2.

3. The projection image display member according to claim 1 or 2, wherein the colored layer extends along the x-axis direction and includes point y2.

4. A projection image display member according to any one of claims 1 to 3, wherein the region provided with the colored layer is designated as a first region, the region not provided with the colored layer as a second region, point y3 is the point on the line connecting point y1 and point y2 that corresponds to the boundary between the first region and the second region, and the thicknesses of the resin layer 1 at points y1 to y3 are denoted as dy1 to dy3 in order, respectively, such that the relationship dy1 ≥ dy3 > dy2 is satisfied.

5. The projection image display member according to claim 4, wherein the distance between the two points y1 and y3 is y1-y3, the distance between the two points y2 and y3 is y3-y2, and the thickness of the projection image display member at points y1 to y3 is Dy1 to Dy3 in order, the relationship (Dy1-Dy3) / (y1-y3) > (Dy3-Dy2) / (y3-y2).

6. The projection image display member according to claim 4 or 5, wherein when the average transmittance of visible light incident at an incident angle of 0° on the center point C2 of the second region is T2(0°), the tangent surface at the center point C2 is the reflective surface, and linearly polarized light containing only P-polarized components is incident from the transparent member 2 side along the incident surface including the orientation axis at the center point C2 at an incident angle θ, and the average reflectance at wavelengths of 400 to 700 nm is determined as Rp2(θ), then both T2(0°) ≥ 70% and Rp2(60°) ≥ 20% are satisfied.

7. A projection image display member according to any one of claims 4 to 6, wherein the tangent surface at the center point C2 of the second region is a reflective surface, and linearly polarized light containing only the P-polarized component is incident from the transparent member 2 side along the incident surface including the orientation axis at the center point C2, at an incident angle θ, and the average reflectance Rp2(θ) at wavelengths of 400 to 700 nm is determined to satisfy Rp2(20°) ≤ Rp2(40°) < Rp2(60°).

8. The projection image display member according to any one of claims 4 to 7, wherein when linearly polarized light containing only the P-polarized component is incident on the center point C2 of the second region at an incident angle of 60° from the transparent member 2 side, with the tangent surface at the center point C2 of the second region being the reflective surface, the change in average reflectance at wavelengths of 400 to 700 nm when the projection image display member is rotated in-plane from 0° to 90° around C2, with the direction of the incident surface including the orientation axis being 0°, is 0% or more and 25% or less.

9. The projection image display member according to any one of claims 2 to 8, wherein the resin layer 2 contains a larger amount of near-infrared absorbing material than the resin layer 1.

10. A head-up display system comprising a projection image display member according to any one of claims 1 to 9, and an image projector 1 that projects an image by irradiating light having a P-polarization component ratio of 51% or more and 100% or less, wherein the P-wave reflector of the projection image display member is located on the light irradiation surface side of the colored layer, and when the region on the projection image display member where the colored layer is provided is defined as a first region, the image projector 1 projects an image onto the first region.

11. Furthermore, the head-up display system according to claim 10, comprising an image projector 2 that projects an image by irradiating light having a P-polarization component ratio of 51% or more and 100% or less, wherein, in the projected image display member, when the region that does not include the colored layer is defined as the second region, the incident angle α (°) of light incident from the image projector 1 to the first region is greater than the incident angle β (°) of light incident from the image projector 2 to the second region.

12. The head-up display system according to claim 10 or 11, wherein the angle of incidence α and the angle of incidence β satisfy 45° ≤ angle of incidence β < angle of incidence α ≤ 75°.

13. A head-up display system according to any one of claims 10 to 12, wherein point A is the center point of the image projection range in the first region, TA(0°) is the average transmittance of the visible light region incident on point A at an incident angle of 0°, the tangent surface at point A is the reflective surface, and RpA(θ) is the average reflectance at wavelengths of 400 to 700 nm obtained by incidenting linearly polarized light containing only P-polarization components along the incident surface including the orientation axis at point A at an incident angle θ, and both TA(0°) ≤ 1% and RpA(α) ≥ 20%.

14. The head-up display system according to any one of claims 10 to 13, wherein, when point B is the center point of the image projection range in the second region, the angle between the line of intersection of the plane containing the electric field vibration direction of the P-polarization component of the light emitted from the image projector 2 and the surface of the projected image display member and the orientation axis at point B is 0° or more and 10° or more, or 80° or more and 90° or less.

15. The head-up display system according to any one of claims 10 to 14, wherein the image projector 2 has a light source unit that irradiates light of an image inside and a curved mirror, and further has a polarizing plate at the display output port.

16. The head-up display system according to any one of claims 10 to 15, wherein the light emitted from the image projector 1 does not have, or has, one peak with a full width at half maximum of 15 nm or less in the wavelength range of 400 to 800 nm.

17. A projection image display member comprising a transparent member, a resin layer, and a P-wave reflector, Two orthogonal lines are drawn on the surface of the projection image display member, passing through the center point C of the projection image display member, such that the shorter of the two lines is the shortest length. The longer line is the x-axis and the shorter line is the y-axis. Points located 50 mm inward from the end of the projection image display member on the x-axis and y-axis are designated as points x1, x2, y1, and y2, respectively. The thickness of the resin layer increases or decreases in the order of point x1, the center point C, and point x2, or in the order of point y1, the center point C, and point y2. A projection image display member that simultaneously satisfies the following (1) to (3), where T(0°) is the average transmittance of visible light incident at the center point C at an incident angle of 0°, Rp(θ) is the average reflectance at wavelengths of 400 to 700 nm obtained by incidenting linearly polarized light containing only P-polarization components along the incident plane including the orientation axis at the center point C at an incident angle θ, with the tangent surface at the center point C being the reflective surface, and (1) T (0°)≧70% (2) Rp (60°)≧20% (3) Rp(20°)≦Rp(40°)<Rp(60°)

18. The projection image display member according to claim 17, wherein when linearly polarized light containing only the P-polarized component is incident on the center point C2 at an incident angle of 60°, with the tangent surface at the center point C serving as the reflective surface, the change in average reflectance at wavelengths of 400 to 700 nm is 0% or more and 25% or less when the projection image display member is rotated in-plane from 0° to 90° around the center point C, with the direction of the incident surface including the orientation axis being 0°.

Images