WO2024043305A1 - Method for producing curved glass with reflective film, curved glass with reflective film, and head-up display system - Google Patents

Abstract

The present invention addresses the problem of providing: a method for producing a curved glass with a reflective film, the method making it possible to apply a reflective film to a windshield glass without impairing the optical performance of the reflective film and while inhibiting the reflective film from creasing; the curved glass with a reflective film; and a head-up display system. The method comprises: a molding step in which a reflective film comprising a substrate, a reflection layer, and a pressure-sensitive adhesive layer in this order and having a degree of heat shrinkage at 140°C of 0.2-5% is placed on the convex surface of a curved glass, with the substrate facing the convex surface, and the reflective film is heated and pressed thereagainst at a temperature of 90-180°C, excluding 180°C, and a pressure of 0.01 MPa or greater; and an application step in which the reflective film is applied to the curved glass, with the pressure-sensitive adhesive layer facing the concave surface.

Description

Method for manufacturing curved glass with reflective film, curved glass with reflective film, and head-up display system

The present invention relates to a method for manufacturing curved glass with a reflective film, a curved glass with a reflective film manufactured by this manufacturing method, and a head-up display system using this curved glass with a reflective film.

2. Description of the Related Art It has been known that a window film is attached to a rear window of an automobile (for example, see Patent Document 1). There are various purposes for attaching a window film, such as blocking ultraviolet rays and improving heat insulation between the interior and exterior of the vehicle.
In recent years, what is called a head-up display or head-up display system projects an image onto the windshield glass of a vehicle and provides the driver with various information such as a map, driving speed, and vehicle status. It has been known.
In a head-up display system, a virtual image of an image including the various information described above, which is projected on a windshield glass, is observed by a driver or the like. The imaging position of the virtual image is located outside the vehicle and in front of the windshield glass. Specifically, the imaging position of the virtual image is usually 1000 mm or more ahead of the windshield glass, and located on the outside side of the windshield glass. Thereby, the driver can obtain the above-mentioned various information without significantly moving his/her line of sight while looking at the outside world ahead. Therefore, when a head-up display system is used, it is expected that drivers will be able to drive more safely while obtaining various information.

A head-up display system can be constructed by forming a reflective film on a windshield glass using a half mirror film.
Various half mirror films that can be used in head-up display systems have been proposed. As a method for forming a reflective film on the windshield glass, there is a method of pasting the reflective film on the inside (driver's side) of the windshield glass using an adhesive layer.

Windshield glass is generally three-dimensionally curved, and in particular, the degree of curvature (curvature) of both edges in the vehicle width direction is greater than the degree of curvature of other parts. Therefore, if the window film is directly attached to the windshield glass, wrinkles will occur in the window film at both edges of the windshield glass.
Therefore, in the method for attaching a window film described in Patent Document 1, a window film having a high heat shrinkage rate in the vehicle width direction is used and is attached while being heat-shrinked. This eliminates the appearance of wrinkles.

However, in Patent Document 1, the surface temperature of the window film is 180°C or more and 230°C or less, and a polyester film that has a large heat shrinkage rate is used. , and heat-shrinked it by applying hot air with a heat gun. If a reflective film is made for a head-up display using a similar method and attached to the windshield glass, the reflection spectrum will be shifted to short wavelengths, changing the external color and changing the image displayed on the head-up display. Even the color was strange and there was a big quality problem.

Patent No. 6758213

The present invention provides a curved glass with a reflective film that does not impair the optical performance of the reflective film and prevents wrinkles from forming on the reflective film when the reflective film is attached to the windshield glass of transportation equipment such as automobiles. The objective is to provide a manufacturing method.
Another object of the present invention is to provide a curved glass with a reflective film manufactured by this method for manufacturing curved glass with a reflective film, and a head-up display system using this curved glass with a reflective film.

The cause of the shortwave shift in the reflection spectrum and deterioration of the appearance color of the reflective film is that when the reflective layer is made of liquid crystal, the material contained in the reflective layer flows into the adhesive layer when it is heated to a high temperature. It is presumed that this is because the reflected wavelength becomes shorter due to the narrower pitch interval of the helical structure of the liquid crystal in the layer. If the reflective layer is a dielectric multilayer film consisting of an optically anisotropic layer and an optically isotropic layer, or a dielectric multilayer film consisting of a high refractive index layer and a low refractive index layer, the film will change when heated to high temperatures. This is thought to be because the reflection wavelength becomes shorter as the film thickness of each layer becomes thinner.
As a result of intensive studies to solve these issues, we created a reflective film that has a high heat shrinkage rate at low temperatures (140°C), and by making it possible to attach it to curved glass at low temperatures, we were able to improve optical performance (reflection). It was found that it was possible to suppress the deterioration of the spectrum (short wave shift of the spectrum and external color), and also to prevent wrinkles in the reflective film attached to the windshield glass.

Furthermore, when attaching a reflective film to a part of the windshield glass, the edges of the reflective film can be smoothed to make the reflection less noticeable, and will not get caught when touched by the user. It was found that the appearance quality could be improved.

Such problems are achieved by the present inventions described in [1] to [15] below.

[1] A method for manufacturing curved glass with a reflective film, which is used for transportation equipment and includes curved glass in which one surface is convex and the other surface is concave, and a reflective film disposed on the concave surface of the curved glass. And,
The reflective film has a base material, a reflective layer, and an adhesive layer in this order, and has a heat shrinkage rate of 0.2% or more and 5% or less at 140°C,
A reflective film is placed on the convex surface of the curved glass so that the base material, reflective layer, and adhesive layer are placed in this order, and the surface temperature of the reflective film is 90°C or higher and lower than 180°C, and pressure is applied to the reflective film. a molding step of heating and pressing the reflective film along the convex surface to mold it under conditions of 0.01 MPa or more;
A method for producing curved glass with a reflective film, comprising a bonding step of bonding a molded reflective film to the curved glass with the adhesive layer facing the concave surface.
[2] The method for manufacturing curved glass with a reflective film according to [1], wherein the molding step is a step of heating and pressing the reflective film onto the curved glass using a pressing member that can be deformed by pressure.
[3] In the molding process, the curved glass and the reflective film placed on the concave surface of the curved glass are placed in a vacuum bag that can be decompressed, and by reducing the pressure inside the vacuum bag, the reflective film is heated and pressed onto the curved glass. The method for producing curved glass with a reflective film according to [1] or [2], which is a step of:
[4] The method for manufacturing curved glass with a reflective film according to [3], wherein a cushion member that can be deformed by pressure is placed between the vacuum bag and the reflective film to reduce the pressure inside the vacuum bag.
[5] The reflective film further has a separator on the side opposite to the base material side of the adhesive layer,
A reflective film is placed on the convex surface of the curved glass so that the base material, reflective layer, adhesive layer, and separator are placed in this order, and a molding process is performed.
After the molding process and before the bonding process, the method includes a peeling process of peeling off the separator,
The method for producing curved glass with a reflective film according to any one of [1] to [4], wherein in the bonding step, the molded reflective film and curved glass are bonded via a liquid.
[6] The method for producing curved glass with a reflective film according to [5], wherein the liquid used in the bonding step contains a surfactant and has a surface tension of 65 mN/m or less with respect to the concave surface of the curved glass.
[7] The reflective film according to any one of [1] to [6], wherein in the laminating step, the molded reflective film and the curved glass are laminated while being pressed by a pressing member that can be deformed by pressure. Method for manufacturing curved glass with film.
[8] The method for manufacturing curved glass with a reflective film according to [7], wherein in the bonding step, the molded reflective film is sequentially pressed from inside to outside in the surface direction of the molded reflective film.
[9] The method for producing a curved glass with a reflective film according to any one of [1] to [8], wherein the area of the reflective film is smaller than the area of the concave surface of the curved glass.
[10] The method for manufacturing curved glass with a reflective film according to [9], wherein the end of the reflective film has a tapered shape.
[11] The method for manufacturing a curved glass with a reflective film according to [9] or [10], wherein the thickness reduction start portion of the tapered shape is a curved surface.
[12] The method for producing a curved glass with a reflective film according to any one of [9] to [11], wherein the reflective film has a planar shape without corners.
[13] The reflective film has a reflective layer consisting of a cholesteric liquid crystal layer formed by fixing a cholesteric liquid crystal phase, the base material is cellulose acylate, and
The method for producing a curved glass with a reflective film according to any one of [1] to [12], which has a hard coat layer on the surface of the base material.
[14] A curved glass with a reflective film produced by the method for producing a curved glass with a reflective film according to any one of [1] to [13].
[15] A head-up display system comprising the curved glass with a reflective film according to [14].

According to the present invention, there is provided a method for manufacturing curved glass with a reflective film that does not impair the optical performance of the reflective film and prevents wrinkles from forming on the reflective film when the reflective film is attached to the windshield glass of an automobile. Can be provided.
Further, according to the present invention, a curved glass with a reflective film that suppresses wrinkles in the reflective film, which is manufactured by the method for manufacturing curved glass with a reflective film of the present invention, and a curved glass with a reflective film that is manufactured using the curved glass with a reflective film, and a curved glass with a reflective film that suppresses wrinkles in the reflective film. We can provide a head-up display system.

FIG. 1 is a top view showing an example of a car equipped with curved glass manufactured by the method for manufacturing curved glass with reflective film of the present invention. FIG. 2 is a cross-sectional view taken along line AA in FIG. FIG. 3 is a perspective view showing the base material of the reflective film. FIG. 4 is a sectional view of the base material shown in FIG. 3. FIG. 5 is a conceptual diagram for explaining the molding process of the method for manufacturing curved glass with a reflective film according to the present invention. FIG. 6 is a cross-sectional view for explaining the mold-making process shown in FIG. 5. FIG. 7 is a cross-sectional view for explaining the liquid application step of the method for manufacturing curved glass with a reflective film according to the present invention. FIG. 8 is a cross-sectional view for explaining the liquid application step of the method for manufacturing curved glass with a reflective film according to the present invention. FIG. 9 is a cross-sectional view showing another example of the mold-making process. FIG. 10 is a diagram for explaining the bonding process of the method for manufacturing curved glass with a reflective film of the present invention. FIG. 11 is a sectional view for explaining the bonding process shown in FIG. 10. FIG. 12 is a cross-sectional view for explaining the bonding process. FIG. 13 is a cross-sectional view showing an example of the shape of the film end when partially pasting. FIG. 14 is a cross-sectional view showing an example of the shape of the film end when partially pasting.

Hereinafter, a method for manufacturing a curved glass with a reflective film, a curved glass with a reflective film, and a head-up display system of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.

The figures described below are illustrative for explaining the present invention, and the present invention is not limited to the figures shown below.
In addition, in the following, "~" indicating a numerical range includes the numerical values written on both sides. For example, when ε ₁ is from the numerical value α ₁ to the numerical value β ₁ , the range of ε ₁ is the range including the numerical value α ₁ and the numerical value β ₁ , and expressed in mathematical symbols as α ₁ ≦ε ₁ ≦β ₁ .
Unless otherwise specified, angles such as "angle expressed in specific numerical values", "parallel", "perpendicular", and "perpendicular" include error ranges generally accepted in the relevant technical field. More specifically, in this specification, parallel, perpendicular, and perpendicular mean a range of parallel ±5°, a range of perpendicular ±5°, and a range of perpendicular ±5°, respectively.
Further, "same" includes the generally acceptable error range in the relevant technical field, and "overall" etc. also includes the generally acceptable error range in the relevant technical field.

"Selective" with respect to circularly polarized light means that the amount of either the right-handed circularly polarized light component or the left-handed circularly polarized light component is greater than the amount of the other circularly polarized light component. Specifically, when referring to "selective", the degree of circular polarization of light is preferably 0.3 or more, more preferably 0.6 or more, and even more preferably 0.8 or more. More preferably, it is substantially 1.0. Here, the degree of circular polarization is expressed as | _{I R -} I _L |/(I _R + I _L ), where the intensity of the right-handed circularly polarized component of light is I R and the intensity of the left-handed circularly polarized component is I _L . is the value to be used.

When we say "sense" regarding circularly polarized light, we mean whether it is right-handed circularly polarized light or left-handed circularly polarized light. The sense of circularly polarized light is that when you look at the light as if it is traveling towards you, if the tip of the electric field vector rotates clockwise as time increases, it is right-handed circularly polarized light, and if it rotates counterclockwise, it is left-handed circularly polarized light. Defined as circularly polarized light.

The term "sense" is sometimes used to refer to the twist direction of the helix of cholesteric liquid crystal. When the helical twist direction (sense) of the cholesteric liquid crystal is right, it reflects right-handed circularly polarized light and transmits left-handed circularly polarized light, and when the sense is left, it reflects left-handed circularly polarized light and transmits right-handed circularly polarized light.

When we say "light," we mean visible light and natural (non-polarized) light, unless otherwise specified. Visible light is electromagnetic waves with wavelengths that can be seen by the human eye, and usually indicates light in the wavelength range of 380 to 780 nm. Invisible light is light in a wavelength range of less than 380 nm or in a wavelength range of more than 780 nm.
Although not limited to this, among visible light, light in the wavelength range of 420 to 490 nm is blue (B) light, and light in the wavelength range of 495 to 570 nm is green (G) light. , light in the wavelength range of 620 to 750 nm is red (R) light.

The "visible light transmittance" is the A light source visible light transmittance defined in JIS (Japanese Industrial Standards) R 3212:2015 (automotive safety glass test method). That is, the transmittance of each wavelength in the wavelength range of 380 to 780 nm is measured using a spectrophotometer using A light source, and the transmittance is obtained from the wavelength distribution and wavelength interval of the CIE (Commission Internationale de l'Eclairage) photopic standard luminous efficiency. This is the transmittance obtained by multiplying the transmittance at each wavelength by the weighted coefficient given by the transmittance and taking a weighted average.
When simply referring to "reflected light" or "transmitted light", it is used in a meaning that includes scattered light and diffracted light.

Note that the polarization state of each wavelength of light can be measured using a spectroradiometer or spectrometer equipped with a circularly polarizing plate. In this case, the intensity of light measured through the right-handed circularly polarizing plate corresponds to I _R and the intensity of light measured through the left-handed circularly polarizing plate corresponds to _IL . Furthermore, measurement can also be performed by attaching a circularly polarizing plate to an illuminance meter or optical spectrometer. The ratio can be measured by attaching a right-handed circularly polarized light transmitting plate and measuring the amount of right-handed circularly polarized light, and by attaching a left-handed circularly polarized light transmitting plate and measuring the amount of left-handed circularly polarized light.

P-polarized light means polarized light that vibrates in a direction parallel to the plane of incidence of light. The incident surface refers to a surface that is perpendicular to a reflective surface (such as a windshield glass surface) and that includes incident light and reflected light. In p-polarized light, the plane of vibration of the electric field vector is parallel to the plane of incidence.

The front phase difference is a value measured using AxoScan manufactured by Axometrics. Unless otherwise specified, the measurement wavelength is 550 nm. For the front phase difference, a value measured using KOBRA 21ADH or WR (manufactured by Oji Scientific Instruments Co., Ltd.) by making light with a wavelength within the visible wavelength range incident in the normal direction of the film can also be used. When selecting a measurement wavelength, the wavelength selection filter can be replaced manually, or the measurement value can be converted using a program or the like.

"Projection image" means an image based on the projection of light from the projector used, rather than the surrounding scenery such as the front. The projected image is observed by the viewer as a virtual image that appears above the projected image display area of the windshield glass.
"Screen image" means an image displayed on a rendering device of a projector or an image rendered by a rendering device on an intermediate image screen or the like. An image is a real image, as opposed to a virtual image.
The image and the projected image may each be a monochrome image, a multicolor image of two or more colors, or a full color image.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The method for manufacturing curved glass with a reflective film, the curved glass with a reflective film, and the head-up display system of the present invention will be described in detail below based on preferred embodiments shown in the accompanying drawings.
In addition, in the following description, the manufacturing method of the curved glass with a reflective film of this invention is also simply called "the manufacturing method of this invention." Furthermore, in the following description, a head up display system (Head up Display) is also referred to as a HUD.

<First embodiment>
FIG. 1 is a schematic top view showing an example of an automobile to which a reflective film is attached by the method for manufacturing curved glass with a reflective film of the present invention.
FIG. 2 is a schematic cross-sectional view taken along line AA in FIG.
FIG. 3 is a perspective view conceptually showing an example of a base material (original fabric) of a reflective film.
FIG. 4 is a schematic cross-sectional view of the base material shown in FIG. 3.
FIG. 5 is a conceptual diagram for explaining an example of the molding step of the method for manufacturing curved glass with a reflective film according to the present invention. Note that FIG. 5 is a view of the windshield glass of the automobile in FIG. 1 viewed from outside the vehicle in the direction of arrow α.
FIG. 6 is a schematic cross-sectional view for explaining the mold-making process shown in FIG. 5.
7 and 8 are schematic cross-sectional views for explaining an example of the liquid application step of the method for manufacturing curved glass with a reflective film of the present invention, respectively. In this example, the liquid application process is performed in the order of FIGS. 7 and 8.
FIG. 9 is a schematic cross-sectional view for explaining another example of the mold-making process. That is, FIG. 9 is a schematic cross-sectional view showing a different example from FIG. 6 of the mold-making process shown in FIG.
FIG. 10 is a conceptual diagram for explaining an example of the bonding process of the method for manufacturing curved glass with a reflective film of the present invention. Note that FIG. 10 is a view of the windshield glass of the automobile shown in FIG. 1 as viewed from the direction of arrow β, that is, from inside the vehicle.
FIG. 11 is a schematic cross-sectional view for explaining the bonding process shown in FIG. 10.
FIG. 12 is a schematic cross-sectional view for explaining an example of the bonding process.
In the following explanation, for convenience of explanation, the upper side in FIGS. 2, 6, 9, 11, and 12 is also referred to as "outside (or outside the vehicle)," and the lower side is also referred to as "inside (or inside the vehicle)." . Further, the upper side of FIGS. 5 and 10 is also referred to as "upper (or upper)" and the lower side is also referred to as "lower (or lower)."

In addition, although the following explanation explains the example where this invention is utilized for a car as an example of transportation equipment, this invention is not limited to this.
That is, the present invention relates to curved glass such as windshield glass installed in various known transportation devices, such as various vehicles other than automobiles, aircraft such as airplanes and helicopters, ships, motorcycles, and trains. It can be suitably used for manufacturing curved glass with a reflective film, curved glass with a reflective film, and HUD.

FIG. 1 shows an example of an automobile using a curved glass with a reflective film of the present invention manufactured by the method of manufacturing a curved glass with a reflective film of the present invention.
As conceptually shown in FIG. 1, the automobile 20 has a windshield glass 201, a rear window 202, and a plurality of side windows 203 as window glasses.
In this embodiment, the reflective film 1 is attached (attached) to the inside of the windshield glass 201, that is, to the inside of the vehicle.
In the following description, for convenience, the vehicle width direction of the vehicle 20 is also referred to as the "WD direction", and the height direction of the vehicle 20 is also referred to as the "HD direction". That is, in FIGS. 5 and 10, which will be described later, the WD direction is the width direction of the vehicle 20, and the HD direction is the height direction of the vehicle 20.

The windshield glass 201 is three-dimensionally curved toward the outside of the vehicle, and as conceptually shown in FIG. 2, the outer surface 204, which is the surface on the outside, that is, the outside of the vehicle, is a convex surface (curved convex surface). The inner surface 205, which is the inner surface, that is, the inner surface of the vehicle, is a concave surface (curved concave surface). The length of this windshield glass 201 in the WD direction is longer than the length in the HD direction.
Further, the windshield glass 201 has a left end 206, which is the left end, and a right end 207, which is the right end in FIG. 2, are curved more steeply than the intermediate part 208 between them. , the curvature of the left end portion 206 and the right end portion 207 is larger than the curvature of the intermediate portion 208.
In the present invention, basically any known vehicle windshield glass (window glass) can be used as the windshield glass, as long as it is curved glass, that is, has a curved surface. In this regard, the same applies to windshield glasses used in other transportation equipment.

The purpose of attaching the reflective film 1 to the windshield glass 201 is, for example, to show the displayed image of the HUD to the driver, to block near-infrared light from sunlight, to block ultraviolet rays, and to protect the interior and exterior of the vehicle. There are various purposes such as improving the insulation properties between the

As conceptually shown in FIG. 3, the reflective film 1 is obtained by cutting a long strip-shaped base material 10. The base material 10 is wound into a roll. Then, this rolled state is developed and the base material 10 is cut into a predetermined size along a cutting line 101 midway in the longitudinal direction to form the reflective film 1.
In the following description, as shown in FIG. 3, the longitudinal direction of the base material 10 before cutting is referred to as the "MD direction", and the width direction of the base material 10 is also referred to as the "CD direction". In this example, as conceptually shown in FIGS. 5 and 10, the HD direction, that is, the height direction of the vehicle, and the MD direction coincide, and the WD direction, that is, the vehicle width direction of the vehicle, and the CD direction. Match.

As conceptually shown in FIG. 4, the base material 10 includes a base material 2, a reflective layer 6 and an adhesive layer 3 formed on one surface of the base material 2, and a side of the base material 2 opposite to the reflective layer 6. It is a laminate having a hard coat layer 4 formed on the surface thereof. Further, in this example, as a preferred embodiment, the base material 10 also has a separator 5 that is peeled off from the adhesive layer 3. What is obtained by peeling off the separator 5 from this base material 10 becomes the reflective film 1 shown in FIG. 1 and the like.
In the following description, the surface of the base material 2 on the reflective layer 6 side is also referred to as the back surface 21, and the surface of the base material on the hard coat layer 4 side is also referred to as the front surface 22.

The base material 2 is the thickest part of the base material 10 (reflective film 1) and has flexibility.
There are no restrictions on the material for forming the base material 2, and for example, various resin materials (plastic materials, resin films) can be used. A suitable example of the material for forming the base material 2 is cellulose acylate. Since cellulose acylate is an optically inert material, for example, even when a driver wears polarized sunglasses, it does not appear rainbow-colored, so it is suitable as a base material for windshield glass.
Note that the thickness t2 of the base material 2 is not particularly limited, but is preferably, for example, 16 to 200 μm, more preferably 20 to 100 μm. Further, in consideration of the processing followability of the reflective film to curved glass, the thickness t2 is more preferably 30 to 80 μm.
Further, the base material 2 may contain an ultraviolet absorber, an infrared absorber, etc., or may be colored by containing a dye or a pigment, if necessary.

The adhesive layer 3 is a portion that is attached to the windshield glass 201.
In the following description, the state in which the reflective film 1 is adhered to the windshield glass 201 via the adhesive layer 3 is also referred to as the "adhered state" for convenience.
There are no restrictions on the material for forming the adhesive layer 3, and various known adhesives can be used. Examples include natural rubber-based, acrylic-based, urethane-based, and polyester-based adhesives. Among these, acrylic adhesives are particularly preferably used in view of weather resistance.
Note that the thickness t3 of the adhesive layer 3 is not limited, but is preferably 2 to 30 μm, more preferably 3 to 25 μm, for example.

As described above, the base material 10 (reflective film 1) has the hard coat layer 4 formed on the surface 22 of the base material 2.
In the reflective film 1 used in the present invention, the hard coat layer 4 is provided as a preferred embodiment. By having the hard coat layer 4, the reflective film 1 obtained from the base material 10 has, for example, excellent abrasion resistance.
The material for forming the hard coat layer 4 is not particularly limited, and for example, an ultraviolet curable acrylic hard coat, a thermosetting silicone hard coat, or the like can be used.
Note that the thickness t4 of the hard coat layer 4 is not particularly limited, but is preferably, for example, 1 to 10 μm, more preferably 2 to 7 μm.

The separator 5 maintains the adhesiveness of the adhesive layer 3 until it is adhered to the windshield glass 201, and when the base material 10 is used, that is, when it is in a pasted state, the adhesive It is peeled off from layer 3. That is, the reflective film 1 does not have the separator 5.
Furthermore, although the separator 5 is basically discarded after being peeled off from the adhesive layer 3, it may be reused. In the base material 10 used in the present invention, the separator 5 is used as a preferred embodiment.
The material for forming the separator 5 is not particularly limited, and for example, resin materials such as polyester and polypropylene can be used. Furthermore, as the separator 5, a paper material such as laminated paper, coated paper, glassine paper, etc., coated with a silicone resin, or an alkyd resin material, etc., coated with a release agent can also be used.
Note that the thickness t5 of the separator 5 is not particularly limited, but is preferably, for example, 16 to 75 μm, more preferably 20 to 60 μm.

The reflective layer 6 provides the reflective film 1 (base material 10) with a function as a half mirror, and for example, when the curved glass with a reflective film of the present invention is used in a HUD, a virtual image created by a driver (user) This is to enable good observation of the projected image.
The reflective layer 6 is not limited, and various known materials used in half mirrors can be used, such as a dielectric multilayer film, a cholesteric liquid crystal layer with a fixed cholesteric liquid crystal phase, a multilayer polymer optical film, and a wire grid. It is possible.
Further, in terms of optical performance, the reflective layer 6 preferably has a reflective color close to colorless and strongly reflects P-polarized light.
A preferred example of the reflective layer 6 is a cholesteric liquid crystal layer.

More specifically, the cholesteric liquid crystal layer is a liquid crystal layer formed by fixing a liquid crystal phase (cholesteric liquid crystal phase) made of cholesterically aligned liquid crystal compounds.
As is well known, a cholesteric liquid crystal layer has a helical structure in which liquid crystal compounds are spirally rotated and stacked. The liquid crystal compound has a structure in which a plurality of pitches (helical pitches) of a liquid crystal compound spirally swirling are stacked.
In addition, as is well known, a cholesteric liquid crystal layer selectively reflects right-handed circularly polarized light or left-handed circularly polarized light in a specific wavelength range, depending on the direction of spiral rotation (sense) of the liquid crystal compound, and reflects other light. Transparent. Furthermore, the cholesteric liquid crystal layer reflects right-handed circularly polarized light and transmits left-handed circularly polarized light, or reflects left-handed circularly polarized light and transmits right-handed circularly polarized light, depending on the direction of rotation (sense) of the helix. The rotation direction of the circularly polarized light reflected by the cholesteric liquid crystal layer corresponds to the helical sense of the cholesteric liquid crystal phase.
In the present invention, various known cholesteric liquid crystal layers having a fixed cholesteric liquid crystal phase can be used as the cholesteric liquid crystal layer.

As mentioned above, the reflective layer 6 is preferably one that strongly reflects P-polarized light. The glare of external light that is visually recognized while driving a car is mainly S-polarized light. Correspondingly, polarized sunglasses are configured to block S-polarized light. Therefore, with a HUD that projects S-polarized light, the image cannot be viewed when wearing polarized sunglasses. Considering this point, it is preferable that the HUD projects P-polarized light, and correspondingly, it is preferable that the reflective layer 6 strongly reflects P-polarized light.
Here, the cholesteric liquid crystal layer selectively reflects right-handed circularly polarized light or left-handed circularly polarized light. Therefore, when a HUD using the curved glass with a reflective film of the present invention uses a projector that emits P-polarized light (linearly polarized light), the reflective film 1 is used to convert the P-polarized light into circularly polarized light and reflect it strongly. preferably has a retardation layer such as a 1/4 retardation layer on the incident side of the reflection layer 6, that is, between the base material 2 and the reflection layer 6.

Further, the reflective film 1 preferably has a polarization conversion layer for optical compensation between the adhesive layer 3 and the reflective layer 6 in order to suppress glare from external light when wearing polarized sunglasses.
As mentioned above, polarized sunglasses are configured to block S-polarized light. The glaring S-polarized light of external light transmitted through the reflective film 1 having a cholesteric liquid crystal layer as the reflective layer 6 is converted from S-polarized light to light containing a P-polarized light component such as elliptically polarized light by passing through the cholesteric liquid crystal layer. It ends up. Therefore, the P-polarized light component passes through the polarized sunglasses and is visually recognized, making it impossible to suppress the glare of external light.
The polarization conversion layer is a layer that converts the polarization of incident external light. By having this polarization conversion layer, the S-polarized light that causes glare from outside light is first disturbed by the polarization conversion layer. As a result, the disturbed S-polarized light is returned to S-polarized light by passing through the cholesteric liquid crystal layer. As a result, by having the polarization conversion layer, S-polarized light incident from the outside can be transmitted through the reflective film 1 as S-polarized light, and the light can be blocked by the polarized sunglasses.
Examples of the polarization conversion layer include a high retardation film having a high retardation Re of 5000 nm or more, a liquid crystal film in which a liquid crystal compound is spirally twisted and oriented in the thickness direction, and the like.
From this point of view, the reflective film 1 is particularly preferably a reflective film having a retardation layer, three cholesteric liquid crystal layers, and a polarization conversion layer described in Example 1 of International Publication No. 2022/123946. This reflective film uses a heat-sealing layer, and the heat-sealing layer produces an adhesive effect when heated. Alternatively, a reflective film in which the heat-sealing layer of the reflective film is replaced with the adhesive layer 3 can also be suitably used. In addition, in this case, it is preferable to stick a separator to the adhesive layer 3 and use it without sticking until it is pasted.

When using a cholesteric liquid crystal layer as the reflective layer 6, the reflective film 1 may have an alignment film between the base material 2 and the reflective layer 6 for aligning the liquid crystal compound.
Further, when a cholesteric liquid crystal layer is used as the reflective layer 6, the reflective film 1 may have only one cholesteric liquid crystal layer, or a cholesteric liquid crystal layer that selectively reflects red light, a cholesteric liquid crystal layer that selectively reflects green light, and a cholesteric liquid crystal layer that selectively reflects red light. It may have multiple cholesteric liquid crystal layers, such as three cholesteric liquid crystal layers: a cholesteric liquid crystal layer that selectively reflects blue light and a cholesteric liquid crystal layer that selectively reflects blue light.

The thickness t6 of the reflective layer is not particularly limited, including cases where the reflective layer 6 is formed of multiple layers, such as when the reflective layer 6 has multiple cholesteric liquid crystal layers, and can obtain the necessary reflective properties such as reflectance. The thickness may be determined depending on the material for forming the reflective layer.

Further, as the base material 10 (reflective film 1), it is preferable to use one having a base material 2 stretched in both the MD direction and the CD direction. As a result, the reflective film 1 obtained from the base material 10 shrinks when heated, that is, has heat shrinkability, and can prevent wrinkles 12 from forming, as will be described later.
Note that the reflective film 1 has a thermal shrinkage rate (shrinkage rate upon heating) that is different in the MD direction and the CD direction. However, the present invention is not limited to this, and the thermal shrinkage rate of the reflective film 1 may be the same in the MD direction and the CD direction.
The reflective film 1 is obtained by peeling off the separator 5 from the base material 10 having such a configuration.

Here, in the present invention, the reflective film 1 has a heat shrinkage rate of 0.2% to 5% (0.2 to 5%) at 140°C. As described above, when the reflective film 1 has different shrinkage rates during heating in the MD direction and CD direction, the lower heat shrinkage rate at 140° C. in the MD direction and the CD direction is 0. It may be 2 to 5%.
In the present invention, by using the reflective film 1 having such a heat shrinkage rate, it is possible to prevent wrinkles from forming in the reflective film 1 in the molding process described later.
This point will be explained in detail later.

The method for producing curved glass with a reflective film of the present invention includes laminating a reflective film having a base material, a reflective layer, and an adhesive layer on the concave surface of a curved glass having a convex surface and a concave surface, and It manufactures curved glass.
In this example, a separator 5 is peeled off from a base material 10 on the concave surface (inner surface 205) of a windshield glass 201 of an automobile 20, which is a curved glass. In this order, the reflective film 1 having the hard coat layer 4 is bonded to the surface 22 of the base material 2, thereby manufacturing the curved glass with the reflective film of the present invention.
The method for manufacturing curved glass with a reflective film of the present invention includes a molding step of molding the reflective film 1 using the convex surface (outer surface 204) of the curved glass, and laminating the molded reflective film to the concave surface of the curved glass. It has a bonding process.
In this example, the method for manufacturing curved glass with reflective film includes a cutting process (see Figure 3), a molding process (see Figures 5 and 6), a liquid application process (see Figures 7 and 8), and a pasting process (see Figures 7 and 8). A combining step (see FIGS. 9 to 12) is performed.

[1] Cutting process The cutting process is a process of cutting the base material 10 to obtain the reflective film 1 with the separator 5, prior to the molding process, liquid application process, and bonding process.

As described above, the base material 10 is wound into a roll to form a base material roll.
As shown in FIG. 3, in the cutting process, the base material 10 is pulled out from the base material roll to unfold the wound state, and the base material 10 is cut along a cutting line 101 midway in the longitudinal direction. Thereby, a reflective film 1 with a rectangular separator 5 is obtained.
As described above, in the long base material 10 before cutting, the MD direction is the longitudinal direction, and the CD direction is the width direction. On the other hand, in the reflective film 1 with the separator 5 (base material 10 after cutting), the CD direction is the long side direction of the rectangle, and the MD direction is the short side direction. As described above, in the reflective film 1, the CD direction corresponds to the vehicle width direction (WD direction) of the vehicle 20, and the MD direction corresponds to the height direction (HD direction) of the vehicle 20.
Note that the base material 10 may be cut by a known cutting method for sheet-like objects (plate-like objects, films, layers). For example, a cutting method using a cutter or the like suitable for cutting flexible films is exemplified.

In the cutting process, the reflective film 1 with the separator 5 is cut into a long piece so that both the longitudinal direction and the transverse direction are sufficiently larger than the vehicle width direction and the height direction of the windshield glass 201. The base material 10 is cut.
That is, the length of the cut reflective film 1 in the CD direction, that is, the length of the long side, is made sufficiently longer than the length of the windshield glass 201 in the WD direction, that is, the length in the vehicle width direction. On the other hand, the length of the reflective film 1 in the MD direction, that is, the length of the short side, is made sufficiently longer than the length of the windshield glass 201 in the HD direction, that is, the length in the height direction. Due to the long sides and short sides having such lengths, the rectangular reflective film 1 has a size sufficient to encompass the windshield glass 201.

[2] Molding process The molding process is a process performed between the cutting process and the liquid application process, and is performed by adjusting the shape of the reflective film 1 obtained in the above-mentioned cutting process to the shape of the windshield glass 201. This is the process of making a mold.
In addition, although this example has a liquid application process as a preferable aspect, when it does not have a liquid application process, a molding process is performed between a cutting process and a bonding process.

As conceptually shown in FIG. 6, in the molding process, first, the reflective film 1 with the separator 5 is laminated (placed, abutted) on the convex surface, that is, the outer surface 204 of the windshield glass 201 (Fig. 6 upper row). At this time, the reflective film 1 is laminated (overlaid) on the convex surface of the windshield glass 201 so that the side opposite to the separator 5, that is, the hard coat layer 4 comes into contact with the convex surface of the windshield glass 201.
In addition, in this example, the reflective film 1 has the hard coat layer 4 as a preferable embodiment. On the other hand, when the reflective film 1 does not have the hard coat layer 4, the reflective film 1 is laminated on the convex surface of the windshield glass 201 so that the base material 2 comes into contact with the convex surface of the windshield glass 201. .
Hereinafter, the state in which the reflective film 1 is laminated on the convex surface of the windshield glass 201 is also referred to as the "outer laminated state" for convenience.
At this time, as conceptually shown in FIG. 5, the CD direction of the reflective film 1 is aligned with the WD direction of the windshield glass 201, and the MD direction of the reflective film 1 is aligned with the HD direction. Moreover, as mentioned above, the reflective film 1 after cutting is sufficiently larger than the windshield glass 201. Therefore, in the outer laminated state, as shown in FIG. 5, the reflective film 1 and the windshield glass 201 are included in the reflective film 1 in the plane direction.

Furthermore, prior to forming the outer layer, a liquid such as water may be applied to the hard coat layer 4 to form a liquid film (layer) on the hard coat layer 4. As a result, when the outer laminated state is set, the outer laminated state is stably maintained by the surface tension of the liquid film.

Next, while maintaining the outer laminated state, the entire portion of the reflective film 1 that overlaps with the windshield glass 201 is heated so that the surface temperature of the reflective film 1 is 90°C or more and less than 180°C, and the pressure on the reflective film 1 is Under conditions of 0.01 MPa or more, the reflective film 1 is heated and pressed along the convex surface (outer surface 204) of the windshield glass 1 to make a mold.
Various methods can be used to heat and press the reflective film 1.

As an example, as conceptually shown in FIG. 6, a method using a pressing member 30 that can be deformed by applying pressure is exemplified.
In this method, as shown in the second row from the top of FIG. 6, while maintaining the outer laminated state in which the reflective film 1 is laminated on the convex surface (outer surface 204) of the windshield glass 201 as described above, is brought into contact with the center of the reflective film 1. That is, the pressing member 30 is brought into contact with a position corresponding to the top of the convex surface of the windshield glass 201 .
The pressing member 30 is, for example, a rubber member, and as described above, is a member that can be deformed by pressure.
Thereafter, as shown in the second to third stages of FIG. 6, the pressing member 30 is further moved and pressed toward the reflective film 1, that is, the windshield glass 201. Furthermore, as shown in the lower part of FIG. 6, the entire surface of the pressing member 30 is brought into contact with the entire surface of the reflective film 1, and the entire surface of the reflective film 1 is pressed by the pressing member 30.
As shown in FIG. 6, the reflective film 1 is superimposed on the convex surface of the windshield glass 201. Further, the pressing member 30 has a shape in which the thickness gradually decreases from the center toward the outside. Therefore, the pressing member 30 presses or pressurizes the reflective film 1 from the center of the reflective film 1 (windshield glass 201) gradually outward.

Next, while maintaining pressure (pressure) on the entire surface of the reflective film 1 by the pressing member 30, as shown in the lower part of FIG. 6, the pressing member 30 is heated by the hot air Q to heat the reflective film 1. .
As a result of this heating, the reflective film 1 contracts and is plastically deformed following the three-dimensional curved shape of the convex surface of the windshield glass 201, so that the reflective film 1 conforms to the convex shape of the windshield glass 201. Here, in the present invention, this heating and pressing is performed under the conditions that the surface temperature of the reflective film 1 is 90° C. or higher and lower than 180° C., and the pressure on the reflective film 1 is 0.01 MPa or higher. This point will be explained in detail later.
Note that there is no restriction on the method of heating the pressing member 30, and various known heating methods such as heating using infrared rays and heating using a heater can be used. Further, the pressing member 30 itself may be made to generate heat by a known method such as a method of incorporating a heating wire or a method of forming the pressing member with a heating element.

Note that the heating of the pressing member 30, that is, the heating of the reflective film 1, is performed before the pressing member 30 presses the entire surface of the reflective film 1, for example, at the time shown in the upper row of FIG. 6, or at the second or third stage in FIG. You may start at this point.
However, in the manufacturing method of the present invention, it is preferable to start heating the pressing member 30 after pressing the entire surface of the reflective film 1 with the pressing member 30, as shown in the illustrated example. Thereby, it is possible to suppress unnecessary shrinkage of the reflective film 1 before the entire surface of the reflective film 1 is pressed against the windshield glass 201, and more preferably prevent wrinkles from forming in the reflective film 1, which will be described later.

In addition to rubber, various materials that can be deformed by pressure can be used as the material for forming the pressing member 30. As an example, those having heat resistance are preferable, and silicone rubber and the like are suitably exemplified.

For heating and pressing the reflective film 1, it is also possible to suitably use a method in which the reflective film 1 is housed in a vacuum bag that can be depressurized and the pressure inside the vacuum bag is reduced.
That is, in this method, as conceptually shown in FIG. 9, the reflective film 1 and the windshield glass 201 are placed on a rubber backing with the reflective film 1 laminated on the convex surface (outer surface 204) of the windshield glass 201. It is accommodated in 31. The rubber bag 31 is a vacuum bag that can be decompressed.
In addition, in this case, when the windshield glass is laminated glass, the reflective film 1 is sandwiched between the convex surface and the concave surface of two curved glasses, and the laminate in which the reflective film 1 is sandwiched between the curved glasses is It may be housed in a rubber bag 31. Regarding this point, the same applies to an example using a cushion member, which will be described later. In this case, the cushion member is preferably placed between the glass on the convex side and the reflective film 1.
Next, the inside of the rubber bag 31 is evacuated to reduce the pressure. As a result, the rubber bag 31 is crushed due to the pressure difference between the atmospheric pressure and the inside of the rubber bag 31, and the reflective film 1 is sandwiched between the inner surface of the rubber bag 31 and the windshield glass 201, and the entire surface of the reflective film 1 is covered with the windshield glass 201. Pressed by
Once the entire surface of the reflective film 1 is pressed (pressurized) by the rubber bag 31, the pressed state is maintained and the rubber bag 31 is heated and pressed under the same temperature and pressure conditions as before.
Note that, similar to the method using the pressing member 30 described above, there is no restriction on the timing to start heating. However, in the manufacturing method of the present invention, it is preferable to start heating after pressing the entire surface of the reflective film 1 with the rubber back 31. Thereby, it is possible to suppress unnecessary shrinkage of the reflective film 1 before applying pressure to the entire surface of the reflective film 1, and more preferably prevent wrinkles from forming in the reflective film 1, which will be described later.

The vacuum bag is not limited to the rubber bag 31 in the illustrated example, and can reduce the pressure inside, and by reducing the internal pressure, the reflective film 1 in the outer laminated state is moved to the windshield glass 201 due to the pressure difference between atmospheric pressure and the inside. Vacuum bags made of various materials can be used as long as they can be pressed. Examples include bags made of resin and bags made of silicone rubber. Among these, a vacuum bag made of silicone rubber is suitable.
Further, there is no limit to the method of heating the rubber bag 31 (vacuum bag), and as with the pressing member 30 described above, a known method can be used, and the rubber bag 31 itself can be heated by a known method. It's okay.

In the molding process, the method of heating and pressing the reflective film 1 onto the convex surface of the windshield glass 201 using a vacuum bag such as the rubber bag 31 has high productivity and good reproducibility and stability. This enables the production of curved glass with a reflective layer.

Here, in the molding process, when heating and pressing the reflective film 1 using a vacuum bag such as the rubber bag 31, a cushion member that can be deformed by pressure is provided between the reflective film 1 and the vacuum bag. It is preferable to arrange a protective member, reduce the pressure inside the vacuum bag, and heat and press the reflective film 1 with the vacuum bag.
During molding, small irregularities may occur on the surface of the reflective film 1. By using a cushion member, the surface of the reflective film can be protected and such inconveniences can be prevented. Moreover, by using the cushion member, the effect of preventing wrinkles in the reflective film 1 described later can be more suitably expressed.

As the cushion member, various known sheet-like materials can be used as long as they can be deformed by pressure.
Specifically, the cushion member preferably has a lower elastic modulus than the reflective film. The elastic modulus of glass is 71 GPa, and the elastic modulus of reflective film is about 5 Gpa. Considering this point, the elastic modulus of the cushion member is preferably 0.1 MPa to 3 GPa or less. If the elastic modulus of the cushion member is too high, the reflective film 1 may undergo uneven deformation due to the cushion member. If the elastic modulus is too low, the cushion member may stretch and deform, resulting in large Period distortion may occur.

The material for forming the cushion member is not limited, but examples include PVB (polyvinyl butyral), a protective laminate film, Teflon (registered trademark), and silicone rubber.
There is also no limit to the thickness of the cushion member, but it is preferably about 50 to 1000 μm, more preferably about 100 to 500 μm.
Furthermore, there is no limit to the size of the cushion member, but it is preferably smaller than the reflective film 1.
Note that such a cushion member can also be used for mold making using the pressing member 30 described above and for mold making using a heat gun and a squeegee, which will be described later.

The heating and pressing of the reflective film 1 may be performed by heating the reflective film 1 using a heat gun and heat shrinking the wrinkles while pressing with a squeegee.
That is, the reflective film 1 may be heated with a heat gun to the same temperature conditions as before, and the reflective film 1 may be heated and pressed with a squeegee to the same pressure as before.

Here, in the present invention, the reflective film 1 has a heat shrinkage rate of 0.2 to 5% at 140°C. More specifically, the reflective film 1 has a heat shrinkage rate of 0.2 to 5% when held at 140° C. for 40 minutes.
As described above, when the reflective film 1 has different shrinkage rates during heating in the MD direction and CD direction, the lower heat shrinkage rate at 140° C. in the MD direction and the CD direction is 0. It is 2-5%.
In addition, in the manufacturing method of the present invention, in the molding step, the surface temperature of the reflective film 1 is 90° C. or more and less than 180° C., and the pressure on the reflective film 1 is 0.01 MPa or more. The reflective film 1 is heated and pressed along the convex surface (outer surface 204) of the windshield glass 201.
By having such a configuration, the present invention can prevent wrinkles from forming on the reflective film without impairing the optical performance of the reflective film when the reflective film is attached.

As described above, in the manufacturing method of the present invention, the reflective film 1 is heated and pressed onto the windshield glass 201 in an outer laminated state in which the reflective film 201 is laminated on the convex surface of the windshield glass. As a result, the reflective film 1 is plastically deformed following the three-dimensional curved shape of the convex surface of the windshield glass 201, and the reflective film 1 is molded into the shape of the convex surface of the windshield glass 201.
Here, when the reflective film 1 is attached (adhered) to the entire surface of the windshield glass 201, the reflective film 1 is usually made larger than the windshield glass 201, as shown in FIG. .
Therefore, when the reflective film 1 is heated and pressed for molding, the reflective film 1 is left over in the periphery in the surface direction, resulting in a state where the reflective film 1 is overlapped. The remaining portion of the reflective film 1 is bent under pressure, and this results in wrinkles in the molded reflective film 1.

On the other hand, in the present invention, a reflective film 1 having a heat shrinkage rate of 0.2 to 5% at 140° C. is used. Therefore, when the reflective film 1 is heated and pressed onto the wind seal glass 201, the reflective film 1 shrinks suitably and absorbs the excess portion at the periphery, causing wrinkles in the reflective film 1 during molding. This can be prevented.
Further, in the manufacturing method of the present invention, heating and pressing is performed in the molding step so that the surface temperature of the reflective film 1 is 90° C. or higher. As mentioned above, the reflective film 1 has a heat shrinkage rate of 0.2 to 5% at 140°C. Therefore, by heating the reflective film 1 so that the surface temperature becomes 90° C. or higher, the reflective film 1 can be appropriately heat-shrinked, and wrinkles can be prevented from forming in the molded reflective film 1.
On the other hand, optical layers (optical films) such as the reflective film 1, particularly the reflective layer 6 such as the cholesteric liquid crystal layer and the dielectric multilayer film, are sensitive to heat. Therefore, when the reflective film 1 is heated at a high temperature, changes in optical properties such as a change in reflection wavelength characteristics (reflection wavelength shift) occur due to deterioration, deterioration, unnecessary thermal contraction, and the like. On the other hand, in the manufacturing method of the present invention, the temperature of heating and pressing in the molding step is such that the surface temperature of the reflective film 1 is less than 180°C. This can prevent the reflective film 1 from deteriorating its optical properties during heating and pressing.
In addition, in the manufacturing method of the present invention, the pressure of heating and pressing in the molding step is 0.01 MPa. Thereby, the reflective film 1 can be reliably aligned with the convex surface of the wind seal glass 201, and the synergistic effect with the heat shrinkage of the reflective film 1 described above can prevent wrinkles from forming on the molded reflective film 1. Furthermore, the reflective film 1 can be suitably molded by plastically deforming it following the three-dimensional curved shape of the convex surface of the windshield glass 201.

In the present invention, the reflective film 1 has a heat shrinkage rate of 0.2 to 5% at 140°C.
If the heat shrinkage rate at 140° C. is less than 0.2%, the reflective film 1 will not undergo sufficient heat shrinkage during heating and pressing in the molding process, causing problems such as the inability to prevent wrinkles.
If the thermal shrinkage rate at 140° C. exceeds 5%, the thermal shrinkage due to heating and pressing in the molding process will be too large, causing problems such as changes in the optical properties of the reflective film 1 (reflective layer 6).
From the viewpoint of preventing wrinkles and suppressing deterioration of optical properties, the heat shrinkage rate of the reflective film 1 at 140°C is preferably 0.5 to 5%, more preferably 0.7 to 4%, and 1 to 3.5%. More preferred.

Further, in the heating and pressing in the molding process, heating is performed so that the surface temperature of the reflective film 1 is 90°C or more and less than 180°C.
If the surface temperature of the reflective film 1 is less than 90° C., the reflective film 1 cannot be sufficiently thermally shrunk, causing problems such as wrinkles in the molded reflective film 1.
Furthermore, if the surface temperature of the reflective film 1 exceeds 180° C., problems such as changes in the optical properties of the reflective film 1 due to heat occur.
From the viewpoint of preventing wrinkles and suppressing deterioration of optical properties, the surface temperature of the reflective film 1 during heating and pressing is preferably 90 to 175°C, more preferably 100 to 150°C, and even more preferably 115 to 140°C.

The surface temperature of the reflective film 1 during heating and pressing in the molding process may be measured by a known method such as thermography or thermocouple.
Note that in the manufacturing method of the present invention, it is often not possible to directly measure the surface temperature of the reflective film 1 depending on the heating and pressing method.
Here, as previously explained with reference to FIG. 4, in the reflective film 1 of the present invention, even the base material 2, which is the thickest member, has a preferable thickness of about 16 to 200 μm. That is, the reflective film 1 of the present invention is very thin. Therefore, the temperature of the reflective film 1 is uniform over the entire area of the reflective film 1 including the surface temperature, and when the pressing member 30 and the rubber back 31 etc. contact the reflective film 1 during heating and pressing, the reflective film 1 is equal to the temperature of the member being heated.
Therefore, if it is not possible to directly measure the surface temperature of the reflective film 1 during heating and pressing, the pressing member 30, rubber back 31, etc. may contact the reflective film 1 during heating and pressing to heat the reflective film 1. The surface temperature of the reflective film 1 may be determined by measuring the temperature of the member.

The pressure applied to the reflective film 1 during heating and pressing is 0.01 MPa or more.
If the pressure of heating and pressing is less than 0.01 MPa, the pressure is low and there are disadvantages such as wrinkles occurring in the molded reflective film 1 and inability to make a mold that sufficiently follows the convex surface (outer surface 204) of the windshield film 201. arise.
The pressure of heating and pressing is preferably 0.05 MPa or more, more preferably 0.06 MPa or more, and even more preferably 0.08 MPa or more. For example, when heating and pressing is performed using the rubber pack 31 described above, by reducing the pressure inside the rubber bag 31, the pressure applied to the reflective film 1 can be set to a maximum of 0.1 MPa, which is preferable as a pressurizing method.
Although there is no upper limit to the pressure during pressurization, it is preferably 0.5 MPa or less.

When the molding process, that is, the plastic deformation of the reflective film 1 is completed, a cutting line 11 is determined on the plastically deformed reflective film 1 slightly inside the contour line 201a of the windshield glass 201, and this cutting line is Cut along 11. Thereby, the reflective film 1 is molded and has a size suitable for the size of the windshield glass 201 without being too large or too small.
The position of the cutting line 11 is preferably 5 to 20 mm inside, more preferably 5 to 10 mm inside of the contour line 202a of the windshield glass 201.
It is preferable to cut along the cutting line 11 after peeling the rectangular reflective film 1 from the windshield glass 201.
Further, there is no restriction on the cutting method, and any known method can be used, such as a method using a cutter or the like as described above.

[3] Liquid application process The liquid application process is a process performed between the molding process and the bonding process, and as conceptually shown in FIG. 7, the separator 5 is peeled off from the molded reflective film 1. As conceptually shown in FIG. 8, this is a step of applying liquid F to the adhesive layer 3 from which the separator 5 has been peeled off.
As a result, a film (layer) of liquid F is formed on the adhesive layer 3, as shown in FIG. This film is maintained until the next step, which is the bonding step.
As mentioned above, the liquid application step is a step performed in a preferred embodiment. Therefore, when the liquid applying step is not performed, after the separator 5 is peeled off from the reflective film 1 as shown in FIG. 1, the bonding step is performed next.
By performing the liquid application step prior to the bonding step, it is possible to prevent the adhesive layer 3, that is, the reflective film 1, from unnecessarily adhering to the concave surface (inner surface 205) of the windshield glass 201 in the subsequent bonding step. . As a result, by performing the liquid application step, workability and efficiency can be improved, and the positional accuracy of the reflective film 1 on the concave surface of the windshield glass 201 can be improved.
The liquid F may be applied to the adhesive layer 3 by a known method, such as a method using a spray.
Further, in the liquid application step, the liquid F is applied not only to the adhesive layer 3 but also to the concave surface of the windshield glass 201, or to the adhesive layer 3 and the concave surface of the windshield glass 201. It may be both.

There is no limit to the liquid F applied in the liquid application step, and various liquids such as water can be used as long as they do not adversely affect the reflective film 1 and the windshield glass 201.
Preferably, the liquid F is exemplified by an aqueous solution of a surfactant.
In the surfactant aqueous solution, there are no restrictions on the surfactant, and various known surfactants can be used. Examples of the surfactant include sodium dodecyl sulfate.
In the aqueous solution of surfactant, the ratio of surfactant to water is preferably 0.005 to 0.2% by mass, more preferably 0.01 to 0.1% by mass.
Further, the surface tension of the liquid F on the windshield glass 201 (concave surface) is preferably 65 mN/m or less. By adjusting the surface tension of the liquid F to an appropriate level, the liquid F that adheres to the surface of the windshield glass 201 spreads uniformly, making it difficult for air bubbles to remain between the adhesive layer of the film and the glass in the next lamination process. It can give an excellent appearance.

[4] Lamination process The lamination process is a process of laminating the molded reflective film 1 to the concave surface, that is, the inner surface 205 of the windshield glass 201, and further pasting it.

As conceptually shown in FIG. 11, in the bonding process, first, the reflective film 1 to which the liquid F has been applied is applied from the adhesive layer 3 (liquid F film) side to the concave surface of the windshield glass 201 ( It is in a state where it is pasted (laminated, abutted, placed) on the inner surface 205). That is, in the bonding process of this example, first, the molded reflective film 1 and the concave surface of the windshield 201 are bonded via the liquid F.
In the following description, the state in which the reflective film 1 to which the liquid F has been applied is bonded to the concave surface (inner surface 205) of the windshield glass 201 is also referred to as the "inner bonded state."
By bonding the reflective film 1 to the concave surface of the windshield glass 201 via the liquid F, the inner bonded state is stably maintained by the surface tension of the film of the liquid F, and the reflective film 1 is bonded to the windshield glass 201. It is temporarily fixed to 201.
At this time, as shown in FIG. 10, with respect to the windshield glass 201, the CD direction of the reflective film 1 is again aligned with the WD direction of the windshield glass 201, and the MD direction of the reflective film 1 is aligned with the HD direction. .

Next, in the inner bonded state, the reflective film 1 is pressed (pressurized) against the concave surface of the windshield glass 201. This pressing is preferably performed by first pressing the center (inside) of the reflective film 1 (windshield glass 201) and gradually moving toward the ends (outside) of the reflective film 1.
As an example, as conceptually shown in FIG. 12, the reflective film 1 is pressed against the concave surface of the windshield glass 201 using a pressing member 32 that can be deformed by pressure while maintaining the inner bonded state. The reflective film 1 is attached to the concave surface of the windshield glass 201 using the adhesive layer 3.
In the example shown in FIG. 12, a pressing member 32 that is thick at the center and gradually becomes thinner toward the ends is used as the pressing member 32 that can be deformed by pressure.
First, as shown in the second row from the top of FIG. 12, the center part of the pressing member 32 is brought into contact with the center of the concave surface (inner surface 205) of the windshield glass 201, and the As shown, the reflective film 1 is gradually pressed by the pressing member 32. By further pressing with the pressing member 32, the entire surface of the reflective film 1 is pressed by the pressing member 32, as shown in the lower part of FIG.
As described above, in this example, the pressing member 32 is deformable by pressure, is thick at the center, and gradually becomes thinner toward the ends, and the pressing member 32 is deformed from the state where the pressing member 32 is in contact with the center. , the reflective film 1 is gradually pressed against the concave surface of the windshield glass 201 by the pressing member 32. Therefore, pressing is performed gradually from the center (inside) of the molded reflective film 1 toward the outside.
Thereby, air bubbles remaining between the adhesive layer 3 and the windshield glass 201 can be pushed out together with the liquid F. As a result, the reflective film 1 is stuck to the windshield glass 201 by the adhesive layer 3.
In addition, in the bonding process, in order to dry the liquid F, the windshield glass 201 to which the reflective film 1 is attached may be stored as is for a predetermined period of time, if necessary. In this case, the windshield glass may be stored while being heated. The storage time and heating temperature may be appropriately set depending on the type of liquid F, the remaining amount, etc.

Furthermore, when pressing the reflective film 1 onto the windshield glass 20 in this bonding step, heating may be applied or the environmental humidity may be reduced to promote removal of the liquid F.
Moreover, if wrinkles remain on the reflective film 1 in the pasted state, the reflective film 1 may be heat-shrinked again by heating the reflective film 1 at a temperature of 90° C. or more and less than 180° C.

In the bonding process, the pressing member 32 that presses the reflective film 1 against the windshield glass 20 and can be deformed by applying pressure is not limited, and various known members may be used as long as it can be deformed by applying pressure. Available. An example is a rubber balloon-shaped member.
Further, in the bonding process, the method of pressing the reflective film 1 onto the windshield glass 20 is not limited to a method using a pressing member that can be deformed by pressure, and various pressing methods can be used. As an example, pressing with a squeegee or the like is exemplified.

As described above, in the present invention, the reflective film 1 is attached to the inner surface 205 of the windshield glass 201.
As a result, it is possible to obtain effects such as, for example, preventing the windshield glass 201 from scattering if it is damaged, blocking ultraviolet rays, and improving heat insulation between the inside and outside of the vehicle.
Furthermore, the reflective film 1 lasts longer than, for example, when it is attached to the outer surface 204 of the windshield glass 201.

In the curved glass with a reflective film of the present invention produced by such a manufacturing method of the present invention, the optical properties of the reflective film 1, such as the shift of the reflected wavelength and the reflected color, are not impaired.
Furthermore, since wrinkles can be prevented from forming on the reflective film 1, the appearance quality can be improved.

<Second embodiment>
Hereinafter, a second embodiment of the method for manufacturing curved glass with a reflective film of the present invention will be described. The following description will focus on the differences from the first embodiment described above, and descriptions of similar matters will be omitted.

In this embodiment, the area of the reflective film 1 is smaller than the area of the windshield glass 201, and the reflective film 1 is attached to a portion of the windshield glass. This embodiment is similar to the first embodiment described above, except that the area of the reflective film is small.
Even in such a case, as described above, by appropriately shrinking the reflective film 1, wrinkles caused by the curved surface of the windshield glass 201 can be absorbed, and wrinkles can be generated at the ends of the reflective film 1. can be suppressed.

Here, in a HUD application, when a reflective film is formed on a portion of the windshield glass 201, there is a problem in that the boundary at the end of the reflective film (edge of the film) is reflected and stands out.
Furthermore, in HUD applications, when the reflective film 1 is formed on a portion of the windshield glass 201, when the user wipes the windshield glass 201 after attachment, the end of the reflective film 1 gets caught and floats. This problem occurred, and it was necessary to improve the quality of the edges of the reflective film 1.

As conceptually shown in FIG. 13, in this embodiment, preferably, the ends of the reflective film 1 are cut diagonally. That is, in this embodiment, the end portion of the reflective film 1 is cut diagonally, which is a so-called tapered shape.
When a film of this type is used and the pasting method of the present invention is performed, the ends (end faces) of the reflective film 1 are not angular, so when observed from the driver's side, the reflected light looks glittering. It can be prevented. In addition, since the ends (end faces) of the reflective film 1 are not angular, the ends of the reflective film 1 will not get caught and will not peel off when wiping the windshield glass 201.
In this embodiment, as conceptually shown in FIG. 14, at the tapered end of the reflective film 1, the position where the thickness of the reflective film 1 starts to decrease toward the outside in the surface direction is curved. It's okay. That is, in the tapered shape of the end of the reflective film 1, the part where the thickness starts to be reduced may be a curved surface.

Furthermore, an effective method for preventing the ends of the reflective film 1 from getting caught when wiping the windshield glass 201 is to make the reflective film 1 have a planar shape that does not have any corners. .
Note that in this example, the planar shape is the shape of the main surface of the film (sheet-like material). The main surface is the largest surface of the film, and usually both sides in the thickness direction. That is, the planar shape is the shape of the film when viewed from a direction perpendicular to the main surface. Moreover, a planar shape without corners means that the planar shape does not have intersections between straight lines.
That is, in this example, examples of the shape of the reflective film 1 include a circle, an ellipse, and a polygon with rounded or curved corners of a planar shape.
Here, the reflective film 1 for HUD is often rectangular or square. Therefore, suitable examples of the planar shape without corners include a rectangle with rounded corners and a square.

In the method for manufacturing a curved glass with a reflective film according to the second embodiment of the present invention, and in the curved glass with a reflective film manufactured by this manufacturing method, the reflective film attached to a part of the windshield glass 201 is Embodiment No. 1, like the first embodiment described above, has no problem with the shift of the reflected wavelength or the reflected color, and can prevent wrinkles from forming on the reflective film. Furthermore, according to this embodiment, the reflected light at the edges is prevented from appearing glittering, the appearance is good up to the edges, the design of the edges is excellent, and the quality against lifting and peeling of the edges is improved. can do.

Although the illustrated embodiments of the method for manufacturing curved glass with a reflective film and the curved glass with a reflective film of the present invention have been described above, the present invention is not limited thereto.

For example, in the above-described embodiment, the curved glass to which the reflective film is attached is an automobile windshield glass (front window), but the present invention is not limited to this. That is, the present invention can be used for various types of windows as long as they are curved glass, and specifically can be used for rear windows and side windows, and can be used for multiple types of windows including windshield glass. Good too. Furthermore, as mentioned above, the present invention is applicable not only to automobiles, but also to curved glass for other transportation equipment, such as windshield glass for airplanes.

Furthermore, when the reflective film is heated in the bonding process, the reflective film shrinks in the same way as the heat shrinkage in the previous molding process.

Furthermore, in the above-described embodiment, the reflective film was treated without heating in the laminating process, but the present invention is not limited to this, and depending on the state of wrinkles in the reflective film, the reflective film may be treated in the laminating process. Heating can also be added.

The HUD (head-up display system) of the present invention is a HUD manufactured by such a manufacturing method of the present invention and has the curved glass with a reflective film of the present invention.
The HUD of the present invention is similar to known HUDs except for using the curved glass with a reflective film of the present invention. Therefore, for the HUD of the present invention, various known configurations can be used, except for using the curved glass with a reflective film of the present invention.

EXAMPLES The present invention will be described in more detail below with reference to Examples. The materials, reagents, amounts and ratios of substances, operations, etc. shown in the following Examples, Comparative Examples, and Production Examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the following examples and reference examples.
Examples 1 to 13 of the present invention and Comparative Examples 1 to 5 are based on the thermal shrinkage rate of the reflective film, the process conditions of the molding process (pressure, heating temperature), the conditions of the pressing member used in the molding process, and This was produced by changing the conditions of the liquid application step, and the other conditions were the same.

<Preparation of reflective film>
The reflective films of Examples 1 to 13 and Comparative Examples 1 to 5 were prepared in the same manner as the liquid crystal reflective film having the hard coat layer, liquid crystal layer, adhesive layer, and separator described in Example 31 of Japanese Patent Application No. 2022-140136. was created.
At this time, a cellulose acylate film with a film thickness of 40 μm and different heat shrinkage rates was used as the base material. (lower value) was 0.1% to 7%, respectively.

<Molding of reflective film>
A commercially available windshield glass (manufactured by Fuyao, X5G05) is disassembled, the interlayer film is removed, and the curved glass on the inside of the car and the curved glass on the outside of the car are separated to make curved glass for molding (curved type). used as.
Place the prepared reflective film on the convex side of the curved glass on the inside of the car, align the CD direction of the reflective film with the WD direction of the windshield glass, and place the separator of the reflective film on the opposite side of the curved glass on the inside of the car (with the hard coat layer on the opposite side of the curved glass on the inside of the car). The inner curved glass side) was placed so that the shape was 2 cm larger than the shape of the glass transparent part, and cut out with a cutter.
Next, the curved glass on the outside of the vehicle was placed so that the concave side was in contact with the reflective film, and the reflective film was sandwiched between the two curved glasses and sealed in a rubber pack (Examples 1 to 10, Comparative Examples 1 to 5). Regarding the reflective films of Examples 11, 12, and 13, a PVB sheet (manufactured by Sekisui Chemical Co., Ltd., S-LEC Film, film thickness 380 μm) smaller in size than the reflective film was placed between the inside glass and the hard coat layer of the reflective film. It was sandwiched and sealed in a rubber pack.
Next, the inside of the rubber pack was evacuated, the amount of vacuum evacuation was adjusted, and a pressure was applied in the range of 0 to 0.1 MPa as shown in the pressurization section of Table 1. 0 MPa at this time indicates a state in which no vacuum is drawn. Further, the rubber pack was heated to a temperature of 70 to 190°C as shown in the heating temperature in Table 1, and maintained for 40 minutes. Then, after lowering the temperature to room temperature, the curved glass was taken out from the rubber pack to obtain a reflective film molded into a curved shape.

<Liquid application process>
Next, the separator was peeled off from the reflective film, and a liquid was sprayed onto the adhesive layer of the reflective film and the inside of the windshield glass (manufactured by Fuyao, X5G05) using a sprayer.
The liquid used was prepared by adding sodium dodecyl sulfate to pure water in an amount of 0 to 0.1% by mass as shown in Table 1. At this time, the surface tension of the liquid with respect to the glass was 48 to 72 mN/m as shown in Table 1.

<Lamination process>
Next, align the adhesive layer of the reflective film with the inside of the windshield glass, press it against the center of the windshield glass with a rubber balloon-shaped pressing member shown in Figure 12, apply pressure, and gradually press the end of the windshield glass. I applied pressure towards it. This forced out the liquid and air bubbles between the reflective film and the windshield glass. Thereafter, it was left at room temperature for one day and dried to obtain a windshield glass to which a reflective film was attached.

Table 1 shows the conditions of the above examples and comparative examples.

The windshield glasses produced in Examples 1 to 13 and Comparative Examples 1 to 5 above were evaluated based on the following criteria.

<Wrinkle evaluation>
Wrinkles in the reflective film attached to the windshield glass were visually observed.
A: There are no wrinkles up to the edges of the film.
B: Very slight wrinkles appeared from the edges of the film.
C: Slight wrinkles within 1 cm were observed at the edges of the film.
D: Many wrinkles of 5 cm or more were generated from the edge of the film.
A to C is an acceptable range.

<Evaluation of bubble removal>
Air bubbles remaining at the interface between the reflective film attached to the windshield glass and the glass were visually observed.
A: There are no bubbles on the entire surface of the windshield glass.
B: Small bubbles remain on the entire surface of the windshield glass.

<Evaluation of small unevenness distortion>
We visually observed small irregularities and distortions in the reflective film attached to the windshield glass.
A: There are almost no small uneven distortions on the entire surface of the windshield glass.
B: Small uneven distortion remains on the entire surface of the windshield glass.
It should be noted that although it is of course preferable to have no such small unevenness distortion, it does not pose a problem in practice.

<Evaluation of wavelength shift>
A visual comparison was made of the appearance of the transparent part of the windshield glass and the case where a reflective film was laminated to a flat glass without heating or pressurizing, and the appearance of the glass when viewed from the front or diagonally.
A: There is almost no difference in color between flat glass and windshield glass.
B: Compared to flat glass, windshield glass has a slightly reddish tinge when viewed from an angle.

Table 2 shows the evaluation results of the glasses produced in Examples 1 to 13 and Comparative Examples 1 to 5 above.

As shown in Table 2, the wrinkles of the reflective films in Examples 1 to 13 are clearly improved compared to Comparative Examples 1 to 5.

10 Base material 101 Cutting line 1 Reflective film 11 Cutting line 2 Base material 21 Back surface (back side surface)
22 Surface (front side)
3 Adhesive layer 4 Hard coat layer 5 Separator 6 Reflective layer 20 Automobile 201 Windshield glass 201a Contour line 202 Rear window 203 Side window 204 External surface 205 Inner surface 206 Left end 207 Right end 208 Intermediate portion 30, 32 Pressing member 31 Rubber pack t2 , t3, t4, t5, t6 Thickness F Liquid Q Hot air

Claims (15)

1. A method for producing curved glass with a reflective film used in transportation equipment, the method comprising curved glass having one surface convex and the other concave, and a reflective film disposed on the concave surface of the curved glass. There it is,
   The reflective film has a base material, a reflective layer, and an adhesive layer in this order, and has a heat shrinkage rate of 0.2% or more and 5% or less at 140°C,
   The reflective film is arranged on the convex surface of the curved glass so that the base material, the reflective layer, and the adhesive layer are arranged in this order, and the surface temperature of the reflective film is 90°C or more and less than 180°C. a molding step of hot pressing and molding the reflective film along the convex surface under conditions where the pressure on the reflective film is 0.01 MPa or more;
   A method for producing curved glass with a reflective film, comprising a bonding step of bonding the molded reflective film to the curved glass with the adhesive layer facing the concave surface.
2. The method for manufacturing curved glass with a reflective film according to claim 1, wherein the molding step is a step of heating and pressing the reflective film onto the curved glass using a pressing member that can be deformed by pressure.
3. In the molding step, the curved glass and the reflective film disposed on the concave surface of the curved glass are housed in a vacuum bag that can be depressurized, and the inside of the vacuum bag is depressurized to remove the reflective film. The method for manufacturing a curved glass with a reflective film according to claim 1, which is a step of heating and pressing the curved glass.
4. 4. The method for manufacturing curved glass with a reflective film according to claim 3, wherein a cushion member deformable by pressure is disposed between the vacuum bag and the reflective film to reduce the pressure inside the vacuum bag.
5. The reflective film further includes a separator on the opposite side of the adhesive layer from the base material side,
   Arranging the reflective film so that the base material, the reflective layer, the adhesive layer, and the separator are arranged in this order on the convex surface of the curved glass, and performing the molding step;
   After the molding step and before the bonding step, a peeling step of peeling off the separator,
   The method for manufacturing curved glass with a reflective film according to claim 1, wherein in the bonding step, the molded reflective film and the curved glass are bonded via a liquid.
6. The method for producing curved glass with a reflective film according to claim 5, wherein the liquid used in the bonding step contains a surfactant and has a surface tension of 65 mN/m or less with the concave surface of the curved glass. .
7. The method for manufacturing curved glass with a reflective film according to claim 1, wherein in the bonding step, the molded reflective film and the curved glass are bonded while pressing with a pressing member that can be deformed by pressure. .
8. The method for manufacturing curved glass with a reflective film according to claim 7, wherein in the bonding step, the pressing member sequentially presses the molded reflective film from the inside to the outside in the surface direction.
9. The method for manufacturing curved glass with a reflective film according to claim 1, wherein the area of the reflective film is smaller than the area of the concave surface of the curved glass.
10. The method for manufacturing curved glass with a reflective film according to claim 9, wherein the end of the reflective film has a tapered shape.
11. The method for manufacturing a curved glass with a reflective film according to claim 10, wherein the thickness reduction start portion of the tapered shape is a curved surface.
12. The method for manufacturing curved glass with a reflective film according to claim 9, wherein the reflective film has a planar shape without corners.
13. The reflective film has a reflective layer made of a cholesteric liquid crystal layer formed by fixing a cholesteric liquid crystal phase, and the base material is cellulose acylate, and
    The method for manufacturing curved glass with a reflective film according to claim 1, wherein the base material has a hard coat layer on the surface.
14. A curved glass with a reflective film produced by the method for manufacturing a curved glass with a reflective film according to any one of claims 1 to 13.
15. A head-up display system comprising the curved glass with a reflective film according to claim 14.

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