WO2018158914A1

WO2018158914A1 - Laminated glass, and optical film for laminated glasses which can be used in same

Info

Publication number: WO2018158914A1
Application number: PCT/JP2017/008337
Authority: WO
Inventors: 金野公彦; 大谷紀昭
Original assignee: マクセルホールディングス株式会社
Priority date: 2017-03-02
Filing date: 2017-03-02
Publication date: 2018-09-07
Also published as: JPWO2018158914A1; JP6871359B2

Abstract

A laminated glass according to the present invention comprises a first glass substrate 22a, a first intermediate film 21a, an optical film 10, a second intermediate film 21b and a second glass substrate 22b in this order, wherein the optical film 10 comprises a transparent base member 11 and a half mirror layer 12 and, when the reflectance of incident light upon the ejection of light from the first glass substrate 22a side is defined as R1 and the reflectance of the incident light excluding interface reflection between the second glass substrate 22b and the outside is defined as R2, a R1/R2 value is 0.9 to 1.4.

Description

Laminated glass and optical film for laminated glass used therefor

The present invention relates to a laminated glass for windshield, which can also be used as an information display panel, and an optical film for laminated glass used therefor.

With the expansion of safe driving support systems for automobiles, the installation of head-up display systems in automobiles has been accelerated for the purpose of quickly capturing various information with a small amount of line of sight while driving and supporting safe driving.

In an automobile head-up display system, information is projected onto the windshield with the light of the projector, the reflected light from the windshield enters the eyes of the driver, and the driver recognizes the information. By the way, since the projection light of the projector is reflected at two locations on the windshield interior side and the exterior side of the windshield, if the reflected light is not on the same line of sight, the reflected image will be a so-called ghost (double image). Will occur. In order to eliminate such a ghost, a laminated glass having a so-called wedge-shaped cross-sectional shape in which the thickness of the upper part of the end surface of the windshield glass of the automobile is thicker than the lower part thereof is used (for example, Patent Document 1).

On the other hand, when such a wedge-shaped wind seal glass is used, the ghost is reduced, but the problem that the brightness of the projected image is lowered remains. For this problem, a method of attaching an optical film provided with a half mirror layer using cholesteric liquid crystal to a wedge-shaped laminated glass, or a method of sandwiching the optical film in an intermediate film of a wedge-shaped laminated glass, It has been proposed to improve luminance (Patent Document 2).

JP-A-2-279437 JP 2016-153281 A

Certainly, when a windshield glass in which the optical film described in Patent Document 2 is sandwiched between interlayer films is used, a high-luminance projection image with reduced ghost is confirmed. However, when an optical film having a cholesteric liquid crystal as a half mirror layer is used for a windshield glass, a problem has been newly confirmed that the impact resistance of the windshield glass is inferior.

The present invention solves the above-described problems, and provides a laminated glass applicable to a head-up display in which no ghost occurs in projection information, the brightness of a projected image is high, and the impact resistance is excellent.

The laminated glass of the present invention is a laminated glass including a first glass substrate, a first intermediate film, an optical film, a second intermediate film, and a second glass substrate in this order. The film includes a transparent base material and a half mirror layer formed on the transparent base material, and the reflectance of incident light when light is incident from the first glass substrate side is R1, When the reflectance of the incident light excluding interface reflection between the second glass substrate and the outside is R2, R1 / R2 is 0.9 to 1.4.

Moreover, the optical film for laminated glass of the present invention is an optical film for laminated glass comprising a transparent base material and a half mirror layer formed on the transparent base material, and the half mirror layer is a metal oxide. The half mirror layer has a refractive index of 1.75 or more, and the optical film has a reflectance of 15% or more.

According to the present invention, it is possible to provide a laminated glass applicable to a head-up display in which no ghost is generated in the projection information, the brightness of the projected image is high, and the impact resistance is excellent.

FIG. 1 is a schematic cross-sectional view showing an example of an optical film for laminated glass. FIG. 2 is a schematic cross-sectional view showing an example of laminated glass.

The present inventors have investigated the cause of inferior impact resistance in a windshield glass in which an optical film provided with a cholesteric liquid crystal layer as a half mirror layer is sandwiched between intermediate films, and found that the cholesteric liquid crystal layer and polyvinyl butyral It was found that the adhesiveness with the manufactured intermediate film was inferior to the adhesiveness between the glass and the intermediate film. Therefore, as a result of studying the material of the half mirror layer provided on the film in order to increase the brightness of the projected image and improve the adhesion between the optical film and polyvinyl butyral, the adhesion between the metal oxide and polyvinyl butyral It was found to be good. As a result of further studies, the inventors have found that the half mirror layer containing a metal oxide and an acrylic resin also has good adhesiveness to polyvinyl butyral, and have completed the present invention.

By the way, in recent automobiles, antennas for electronic equipment such as AV equipment and ETC are provided near the windshield glass. For this reason, the windshield glass using the laminated glass also needs radio wave transmission. The conventional half mirror layer is formed from a metal vapor deposition film made of aluminum or the like. However, if laminated glass having a half mirror layer made of a metal vapor deposition film is used for a windshield glass, there is a concern that radio wave transmission may be inconvenient. There is. For this reason, the present inventors decided to use a high refractive index film instead of the metal vapor deposition film for the half mirror layer.

For example, by setting the refractive index of the half mirror layer to 1.7 or more and increasing the difference from the refractive index of air (about 1.0), the reflectance at the interface with air increases, and the half mirror effect Is obtained. However, when used for laminated glass, the half mirror layer is covered with an intermediate film made of a resin such as polyvinyl butyral having a refractive index of about 1.5, and the difference in refractive index between the half mirror layer and the intermediate film layer is Since the refractive index difference is smaller than that of air, the reflectance is not improved as in the air, and the half mirror effect is considered to be reduced. As a result, the luminance improvement is considered to be slight. The inventors of the present invention have made a study without being bound by such a fixed idea. As a result, the refractive index of the half mirror layer is made larger than 1.75, and the thickness thereof is adjusted so that the reflectance of the optical film is 15%. If it was set as the above, it confirmed that the brightness | luminance improvement effect of projection information was acquired, and came to this invention. Moreover, when the refractive index of the half mirror layer is 1.75 or more, the impact resistance of the laminated glass is improved because the metal oxide content increases.

Hereinafter, embodiments of the present invention will be described.

(Optical film for laminated glass)
First, an embodiment of the optical film for laminated glass of the present invention will be described. The optical film for laminated glass of this embodiment includes a transparent substrate and a half mirror layer formed on the transparent substrate, and the half mirror layer includes a metal oxide and an acrylic resin. The refractive index of the half mirror layer is 1.75 or more, and the reflectance of the optical film is 15% or more.

Since the optical film for laminated glass of the present embodiment includes the half mirror layer, it can reflect a certain visible ray and improves the adhesiveness with the resin layer. For this reason, when the optical film for laminated glass is incorporated in laminated glass, the back reflection of incident light can be suppressed, ghosting is not generated in the projection information, the brightness of the projected image is increased, and the impact resistance is excellent. Can provide a head-up display. This will be described in detail in the description of the embodiment of the laminated glass of the present invention.

Specifically, a resin layer is disposed on both sides of the laminated glass optical film, a first glass substrate and a second glass substrate are disposed on both sides of the resin layer, and the first glass substrate side. R1 / R2 where R1 is the reflectance of the incident light when light is incident from R1, and R2 is the reflectance of the incident light excluding the interface reflection between the second glass substrate and the outside (air). Can be set to 0.9 to 1.4, more preferably 1.0 to 1.4. That is, reflection of incident light (back surface reflection) at the interface between the second glass substrate and the outside can be suppressed. This point will also be described in detail in the description of the laminated glass of the embodiment of the present invention.

Hereinafter, the optical film for laminated glass of the present embodiment will be described with reference to the drawings.

FIG. 1 is a schematic cross-sectional view showing an example of an optical film for laminated glass of the present embodiment. In FIG. 1, the optical film 10 for laminated glass of the present embodiment includes a transparent base material 11 and a half mirror layer 12 formed on the transparent base material 11.

<Transparent substrate>
As a transparent base material which comprises the optical film for laminated glasses of this embodiment, if it is formed with the material which has translucency, it will not specifically limit. Examples of the transparent substrate include polyester resins (eg, polyethylene terephthalate, polyethylene naphthalate, etc.), polycarbonate resins, polyacrylate resins (eg, polymethyl methacrylate), alicyclic polyolefin resins, Polystyrene resin (for example, polystyrene, acrylonitrile / styrene copolymer (AS resin), etc.), polyvinyl chloride resin, polyvinyl acetate resin, polyethersulfone resin, cellulose resin (for example, diacetyl cellulose, triacetyl) Cellulose or the like) or a resin such as norbornene-based resin processed into a film or sheet can be used. Examples of methods for processing the resin into a film or sheet include an extrusion molding method, a calender molding method, a compression molding method, an injection molding method, a method in which the resin is dissolved in a solvent, and the like. You may add additives, such as antioxidant, a flame retardant, a ultraviolet absorber, an easy lubricant, and an antistatic agent, to the said resin. The thickness of the transparent substrate may be, for example, 10 to 500 μm.

<Half mirror layer>
The half mirror layer constituting the optical film for laminated glass of the present embodiment contains a metal oxide and an acrylic resin, and the refractive index of the half mirror layer needs to be 1.75 or more. 1.8 or more is more preferable.

The thickness of the half mirror layer is preferably adjusted so that the reflectance of the optical film is 15% or more. The thickness of the half mirror at which the reflectance of the optical film is 15% or more varies depending on the transparent substrate, the type of metal oxide, the amount added, the type of the acrylic resin, and the like. Moreover, if the thickness of the half mirror layer is 30 nm or more, the radiation curing reaction of an acrylic resin containing a radiation curable functional group, which will be described later, is sufficiently advanced, or scratches during optical film production can be suppressed.

Hereinafter, the constituent materials of the half mirror layer will be described.

[Metal oxide]
The metal oxide is not particularly limited as long as the half mirror layer has a refractive index of 1.75 or more. For example, zirconium oxide, titanium oxide, niobium pentoxide, tantalum oxide, cerium oxide Etc. can be used. Among these, titanium oxide is most preferable because it has a high refractive index and can easily form a half mirror layer having a refractive index of 1.75 or more.

The average particle diameter of the metal oxide is preferably 70 nm or less, more preferably 50 nm or less, and still more preferably 30 nm or less. The lower limit of the average particle diameter of the metal oxide is about 5 nm. If the particle size is smaller than this, dispersion treatment becomes difficult, or the amount of metal oxide added cannot be increased, and it becomes difficult to make the refractive index of the half mirror layer 1.8 or more. The average particle diameter is the average value of the major axis diameter and the minor axis diameter of at least 10 particles of the metal oxide particles using a scanning electron microscope (SEM) or a transmission electron microscope (TEM). Further, the average value of the major axis diameter and the average value of the minor axis diameter are obtained by averaging.

[Acrylic resin]
As the acrylic resin, a radiation curable resin is preferable. The radiation curable resin can be obtained, for example, by subjecting an acrylic monomer, acrylic oligomer, urethane acrylate, epoxy acrylate or the like containing a radiation curable functional group to a radiation curing treatment.

<Optical film>
The method for producing the optical film is not particularly limited. For example, the optical film is dispersed after mixing the metal oxide, the radiation curable monomer, a photopolymerization initiator, a solvent, and a dispersant as necessary. A half-mirror layer-forming coating material is prepared by applying a treatment, and the half-mirror layer-forming coating material is applied to the transparent substrate, then dried, and irradiated with ultraviolet rays or the like to cure the half-mirror layer-forming coating material. It can produce by doing.

The dispersion treatment of the paint for forming the half mirror layer can be performed by a technique such as a ball mill, a sand mill, or an ultrasonic dispersion. The coating for forming the half mirror layer can be performed by a technique such as gravure coating, reverse roll coating, bar coating, slit die coating or the like. Furthermore, examples of the solvent include ketone solvents such as methyl ethyl ketone and cyclohexanone, aromatic solvents such as toluene and xylene, alcohol solvents such as ethanol and isopropanol, aliphatic solvents such as octane and decane, and other glycols. Solvents such as solvents and glycol ether solvents can be used.

(Laminated glass)
Next, an embodiment of the laminated glass of the present invention will be described. The laminated glass of the present embodiment includes a first glass substrate, a first intermediate film, an optical film, a second intermediate film, and a second glass substrate in this order, and the optical film is transparent. A substrate and a half mirror layer formed on the transparent substrate, the reflectance of incident light when light is incident from the first glass substrate side is R1, and the second When the reflectance of the incident light excluding interface reflection between the glass substrate and the outside (air) is R2, R1 / R2 is 0.9 to 1.4.

In the laminated glass of the present embodiment, R1 / R2 can be set to 0.9 to 1.4, more preferably 1.0 to 1.4. Thereby, since reflection (back surface reflection) of incident light at the interface between the second glass substrate and the outside can be suppressed, no ghost is generated in the projection information, and the brightness of the projection image can be increased.

Although the optical film used for the laminated glass of this embodiment will not be specifically limited if the said characteristic can be exhibited, It is preferable to use the optical film for laminated glasses of the above-mentioned embodiment of this invention. Since the optical film for laminated glass of the above-described embodiment includes the above-described half mirror layer, it can reflect a certain visible ray and improves the adhesiveness with an intermediate film made of a resin layer. For this reason, when the optical film for laminated glass is incorporated in laminated glass, the back reflection of incident light can be suppressed, ghosting is not generated in the projection information, the brightness of the projected image is increased, and the impact resistance is excellent. Can provide a head-up display.

Hereinafter, the laminated glass of this embodiment will be described with reference to the drawings.

FIG. 2 is a schematic cross-sectional view showing an example of the laminated glass of the present embodiment. In FIG. 2, the laminated glass 20 of this embodiment comprises a first glass substrate 22a, a first intermediate film 21a, an optical film 10, a second intermediate film 21b, and a second glass substrate 22b. In this order. The optical film 10 includes a transparent substrate 11 and a half mirror layer 12 formed on the transparent substrate 11.

In FIG. 2, the reflectance of incident light when light is incident from the glass substrate 22a side is R1, and the reflection of the incident light excluding interface reflection between the second glass substrate and the outside (air) is removed. When the reflectance is R2, R1 / R2 is set to 0.9 to 1.4, more preferably 1.0 to 1.4. That is, R1 is a reflectance based on reflected light at the outer surface of the glass substrate 22a with respect to incident light, the surface of the half mirror layer 12, and the interface between the second glass substrate and the outside, and R2 is a glass substrate with respect to incident light. It is a reflectance based on the reflected light on the outer surface of 22a and the surface of the half mirror layer 12.

Moreover, it is preferable that the visible light transmittance of the laminated glass 20 measured in accordance with Japanese Industrial Standard (JIS) R3211 is 70% or more. Thereby, the said laminated glass can be used as a windshield.

<Optical film>
The optical film used in the laminated glass of this embodiment is preferably the optical film for laminated glass of the above-described embodiment of the present invention, but the description thereof is omitted.

<Intermediate film>
The intermediate film used in the present embodiment is formed from a transparent resin. The intermediate film functions as an adhesive layer for joining two glass substrates. Accordingly, the transparent resin for forming the intermediate film is not particularly limited as long as it has adhesiveness. For example, polyvinyl butyral resin, ethylene-vinyl acetate copolymer resin, polyvinyl acetal resin, or the like may be used. it can.

The intermediate film preferably has a wedge-shaped cross-sectional shape. Thereby, generation | occurrence | production of a ghost (double reflection) can be prevented more reliably. The method of processing the cross-sectional shape of the intermediate film into a wedge shape is not particularly limited, but for example, the method described in Patent Document 1 (Japanese Patent Laid-Open No. Hei 2-279437) can be used.

The intermediate film may contain various adjusting agents such as an ultraviolet absorber, an antioxidant, an antistatic agent, and a heat stabilizer.

The thickness of the intermediate film is not particularly limited, but may be 0.05 to 3 mm, for example, to ensure transparency and penetration resistance when a laminated glass is used.

<Glass substrate>
The glass substrate used in the present embodiment is not particularly limited, and for example, a transparent glass substrate having a thickness of 1 to 3 mm can be used.

Hereinafter, the present invention will be described in detail based on examples. However, the present invention is not limited to the following examples. In addition, unless otherwise indicated, in the following, “part” means “part by mass”.

Example 1
<Production of optical film>
First, a polyethylene terephthalate (PET) film (trade name “Lumirror U34”, thickness: 50 μm, manufactured by Toray Industries, Inc.) was prepared as a transparent substrate.

Next, the following materials were stirred and mixed, and then subjected to a dispersion treatment with a sand grind mill to prepare a dispersion.
(1) Metal oxide (ultrafine particle titanium oxide manufactured by Ishihara Sangyo Co., Ltd., trade name “TTO51 (A)”, average particle diameter: 20 nm): 80 parts (2) Dispersant (trade name “Solspers, manufactured by Lubrizol Co., Ltd.” 32000 "): 7.6 parts (3) UV curable resin (urethane acrylate manufactured by Nippon Kayaku Co., Ltd., trade name" KAYARAD DPHA-40H "): 11.78 parts (4) Photopolymerization initiator (manufactured by BASF) , Trade name “Irgacure 907”): 0.62 part (5) methyl ethyl ketone: 150 parts (6) cyclohexanone: 150 parts

Next, a mixed solvent of methyl ethyl ketone and cyclohexanone having a mass ratio of 50:50 is prepared, the dispersion is diluted 12.5 times with the mixed solvent, and the diluted solution is filtered through a half mirror layer. A forming coating solution was obtained.

Subsequently, the coating solution for forming the half mirror layer was applied on the PET film using a bar coater so that the thickness of the half mirror layer after curing was 80 nm, and dried at 100 ° C. Formed. Its UV coating film (the maximum wavelength: 365 nm, light source: high pressure mercury lamp, integrated light quantity: 400 mJ / cm ²⁾ to cure the coating by irradiation with, to form a half mirror layer on the PET film, Example 1 optical film was produced.

<Production of laminated glass>
First, a polyvinyl butyral (PVB) film (PVB film manufactured by Sekisui Chemical Co., Ltd., trade name “ESREC film”, thickness: 0.38 mm) used for an interlayer film is disclosed in Patent Document 1 (Japanese Patent Laid-Open No. Hei 2-279437). ) Was processed in the same manner as in Example 2 to prepare two PVB films having a wedge-shaped cross-sectional shape. Further, two glass sheets with a thickness of 2 mm (manufactured by Nippon Sheet Glass Co., Ltd.) were prepared as glass substrates.

Next, the optical film produced above is sandwiched between the two PVB films so that the cross-sectional shape becomes a wedge shape, and further, the two float glasses are laminated on both sides of the PVB film to produce a laminate. did. Thereafter, the laminate was wrapped in a rubber bag and vacuum deaerated for 10 minutes in an autoclave heated to 90 ° C. to pre-adhere each layer of the laminate. Subsequently, the pre-adhered laminate was cooled to room temperature, then removed from the rubber bag, and again heated and pressurized in an autoclave at 135 ° C. under a pressure of 12 kg / cm ² for 30 minutes to produce the laminated glass of Example 1. did.

(Example 2)
An optical film was prepared in the same manner as in Example 1 except that the thickness of the half mirror layer after curing was adjusted to 100 nm, and the optical film was used in the same manner as in Example 1 except that this optical film was used. The laminated glass of Example 2 was produced.

(Example 3)
The following materials were stirred and mixed, and then subjected to dispersion treatment with a sand grind mill to prepare a dispersion.
(1) Metal oxide (ultrafine particle titanium oxide manufactured by Ishihara Sangyo Co., Ltd., trade name “TTO51 (A)”, average particle diameter: 20 nm): 80 parts (2) Dispersant (trade name “Solspers, manufactured by Lubrizol Co., Ltd.” 32000 "): 7.6 parts (3) UV curable resin (urethane acrylate manufactured by Nippon Kayaku Co., Ltd., trade name" KAYARAD DPHA-40H "): 25.36 parts (4) Photopolymerization initiator (manufactured by BASF) , Trade name "Irgacure 907"): 1.33 parts (5) methyl ethyl ketone: 171.1 parts (6) cyclohexanone: 171.1 parts

An optical film was produced in the same manner as in Example 1 except that the coating solution for forming the half mirror layer was used, and the laminated glass of Example 3 was obtained in the same manner as in Example 1 except that this optical film was used. Produced.

(Comparative Example 1)
A laminated glass of Comparative Example 1 having a configuration of float glass / intermediate film / intermediate film / float glass was produced in the same manner as in Example 1 except that the optical film produced in Example 1 was not used.

(Comparative Example 2)
A laminated glass of Comparative Example 2 having a configuration of float glass / intermediate film / PET film / intermediate film / float glass was produced in the same manner as in Example 1 except that the half mirror layer was not formed on the PET film.

(Comparative Example 3)
An optical film was prepared in the same manner as in Example 1 except that the thickness of the half mirror layer after curing was adjusted to 140 nm, and a comparison was made in the same manner as in Example 1 except that this optical film was used. The laminated glass of Example 3 was produced.

(Comparative Example 4)
The following materials were stirred and mixed, and then subjected to dispersion treatment with a sand grind mill to prepare a dispersion.
(1) Metal oxide (ultrafine titanium oxide manufactured by Ishihara Sangyo Co., Ltd., trade name “TTO51 (A)”, average particle size: 20 nm): 72 parts (2) Dispersant (trade name “Solspers, manufactured by Lubrizol Corporation” 32000 "): 6.84 parts (3) UV curable resin (urethane acrylate manufactured by Nippon Kayaku Co., Ltd., trade name" KAYARAD DPHA-40H "): 39.10 parts (4) Photopolymerization initiator (manufactured by BASF) , Trade name “Irgacure 907”): 2.06 parts (5) methyl ethyl ketone: 180 parts (6) cyclohexanone: 180 parts

An optical film was prepared in the same manner as in Example 1 except that the coating solution for forming the half mirror layer was used, and the laminated glass of Comparative Example 4 was prepared in the same manner as in Example 1 except that this optical film was used. Produced.

Next, the following characteristics were evaluated using the laminated glasses of Examples 1 to 3 and Comparative Examples 1 to 4 that were produced.

<Reflectance of optical film>
The reflectance of the optical film was measured using a simultaneous photometric spectral color difference meter “SQ-2000” manufactured by Nippon Denshoku Industries Co., Ltd. The measurement conditions were a circular region with a diameter of 10 mm of the optical film as a measurement region, reflection measurement was performed under conditions including regular reflection, a Y value was obtained, and the obtained Y value was taken as the reflectance of the optical film.

<Refractive index of half mirror layer>
The refractive index of the half mirror layer was measured using a reflection spectral film thickness meter “FE3000” manufactured by Otsuka Electronics Co., Ltd. and standard software “FE Series ver4”. Measurement conditions are absolute reflection, manual mode, aluminum reflector is used for reference, lens is Refrec × 20, NA = 0.400, no filter, slit is 0.2 × 2 mm, sampling is 524 msec, integration is Nine times, gain was normal.

<Ratio of reflectance R1 / R2>
The reflectance ratio R1 / R2 was measured by combining a spectrophotometer “V-570” manufactured by JASCO Corporation and an integrating sphere unit “ILN-472” manufactured by JASCO Corporation. The measurement was performed in the wavelength range of 380 to 780 nm and converted into the total light reflectance. Specifically, first, the reflectance when light was incident from one side of the float glass of the laminated glass was measured and set to R1. Next, the outside of the outer surface of the float glass on the side opposite to the incident light side was roughened with sandpaper, then painted with oil-based black ink, and the reflectance was measured with a black tape applied, and R2 was obtained. Finally, the reflectance ratio R1 / R2 was calculated.

<Luminance of projected image>
The brightness of the projected image was measured using a goniophotometer “GP200” manufactured by Murakami Color Research Laboratory. Specifically, the reflection characteristics of light incident on the laminated glass at an incident angle of 60 ° were measured, the light intensity at the reflection angle of 60 ° was relatively evaluated, and the obtained relative value was defined as the luminance. The produced laminated glass has a wedge shape in cross section, but light is incident from the side with the thinner cross section of the laminated glass, and the reflected light is emitted from the side with the thicker cross section of the laminated glass. Set in the device.

<Impact resistance of laminated glass>
First, the laminated glass was stored at room temperature and −20 ° C. for 24 hours or more. Next, the laminated glass after storage was placed on an aluminum plate having a thickness of 10 mm, and the center of the laminated glass was struck with a hammer. Samples stored at −20 ° C. were removed from the freezer and immediately placed on an aluminum plate and struck with a hammer. Laminated glasses other than Comparative Examples 1 and 2 were placed on an aluminum plate with the glass surface on the half mirror layer side of the optical film facing up. The impact resistance of the laminated glass was evaluated according to the following criteria.
(1) When the peeled area of the adhesive surface between the intermediate film and the optical film was less than 30% of the total adhesive surface, the impact resistance was judged as “good”.
(2) When the peeled area of the adhesive surface between the intermediate film and the optical film was 30% or more and less than 50% of the entire adhesive surface, the impact resistance was judged as “good”.
(3) When the peeled area of the adhesive surface between the intermediate film and the optical film was 50% or more of the total adhesive surface, the impact resistance was judged as “poor”.

<Display image quality>
Display information light from the display unit installed on the lower side of the laminated glass is projected in a state where the incident angle is 60 ° with respect to the laminated glass, and the presence or absence of a ghost is visually confirmed at a predetermined position. The quality of the displayed image was evaluated. The laminated glass was set so that the upper end cross section was thick.
(1) When a ghost was not confirmed remarkably in the display image, it was judged that the display image was “good”.
(2) When a ghost was remarkably confirmed in the display image, the display image was determined to be “defective”.

The results are shown in Table 1.

From Table 1, the laminated glass of Examples 1 to 3 having a reflectance ratio of 1.4 or less had high projected image brightness and good display image because the reflectance of the optical film was 15% or more. It turns out that it is. Further, in the laminated glasses of Examples 1 to 3, since the optical film was provided with a half mirror layer containing a metal oxide, the impact resistance was good at both room temperature and low temperature.

On the other hand, in Comparative Example 1, since no optical film was used, it can be seen that the reflectance ratio of the laminated glass is large and the brightness of the projected image is low. In Comparative Example 2, since the PET film without the half mirror layer was used for the optical film, the reflectance of the optical film was small, the reflectance ratio of the laminated glass was larger than 1.4, and the brightness of the projected image was the optical film. It can be seen that there is no significant difference from Comparative Example 1 in which no is used. Moreover, in the comparative example 2, since the half mirror layer containing a metal oxide is not provided in the optical film, it turns out that impact resistance is inferior. In Comparative Example 3, a half mirror layer is provided, but since an optical film having a reflectance of less than 15% is used, the reflectance ratio of the laminated glass is greater than 1.4, and the brightness of the projected image is the same as that of Comparative Example 1. It turns out that there is not much difference. In Comparative Example 4, since the reflectance ratio of the laminated glass is greater than 1.4, it can be seen that the brightness of the projected image is not significantly different from that of Comparative Example 1. This is considered because the reflectance of the optical film provided with the half mirror layer used in Comparative Example 4 is smaller than 15%. In Comparative Example 4, it can be seen that the impact resistance at −20 ° C. is inferior because the refractive index of the half mirror layer is lower than 1.75.

The present invention can be implemented in forms other than those described above without departing from the spirit of the present invention. The embodiments disclosed in the present application are merely examples, and the present invention is not limited thereto. The scope of the present invention is construed in preference to the description of the appended claims rather than the description of the above specification, and all modifications within the scope equivalent to the claims are construed in the scope of the claims. It is included.

DESCRIPTION OF SYMBOLS 10 Optical film for laminated glass 11 Transparent base material 12 Half mirror layer 20 Laminated glass 21a, b Intermediate film 22a, b Glass substrate

Claims

A laminated glass including a first glass substrate, a first intermediate film, an optical film, a second intermediate film, and a second glass substrate in this order,
The optical film includes a transparent substrate and a half mirror layer formed on the transparent substrate,
The reflectance of incident light when light is incident from the side of the first glass substrate is R1, and the reflectance of incident light excluding interface reflection between the second glass substrate and the outside is R2. Then, a laminated glass characterized in that R1 / R2 is 0.9 to 1.4.
The laminated glass according to claim 1, wherein the half mirror layer includes a metal oxide and an acrylic resin.
The laminated glass according to claim 2, wherein the average particle diameter of the metal oxide is 70 nm or less.
The laminated glass according to claim 2 or 3, wherein the metal oxide is titanium oxide.
The laminated glass according to any one of claims 1 to 4, wherein the refractive index of the half mirror layer is 1.75 or more.
The laminated glass according to any one of claims 1 to 5, wherein the optical film has a reflectance of 15% or more.
The laminated glass according to any one of claims 1 to 6, wherein R1 / R2 is 1.0 to 1.4.
The laminated glass according to any one of claims 1 to 7, wherein the intermediate film is made of a transparent resin.
The laminated glass according to any one of claims 1 to 8, wherein the interlayer film has a wedge-shaped cross-sectional shape.
The laminated glass according to any one of claims 1 to 9, wherein the visible light transmittance measured in accordance with JIS R3211 is 70% or more.
An optical film for laminated glass comprising a transparent substrate and a half mirror layer formed on the transparent substrate,
The half mirror layer includes a metal oxide and an acrylic resin,
The refractive index of the half mirror layer is 1.75 or more,
An optical film for laminated glass, wherein the optical film has a reflectance of 15% or more.
The optical film for laminated glass according to claim 11, wherein the average particle diameter of the metal oxide is 70 nm or less.
The optical film for laminated glass according to claim 11 or 12, wherein the metal oxide is titanium oxide.
The optical film for laminated glass according to any one of claims 11 to 13, wherein the acrylic resin contains a radiation curable resin.
A resin layer is arranged on both sides of the optical film for laminated glass,
Arranging a first glass substrate and a second glass substrate on both sides of the resin layer;
The reflectance of incident light when light is incident from the side of the first glass substrate is R1, and the reflectance of incident light excluding interface reflection between the second glass substrate and the outside is R2. The optical film for laminated glass according to any one of claims 11 to 14, wherein R1 / R2 is 0.9 to 1.4.
The optical film for laminated glass according to claim 15, wherein R1 / R2 is 1.0 to 1.4.