JPWO2020054286A1 - Glass, laminated glass - Google Patents

Abstract

An object of the present invention is to improve the response speed of a dimming element at a low temperature in a glass having a dimming element. The glass of the present invention is a glass for a vehicle, and is arranged in at least a part of a glass plate, a transparent region defined by the glass, and a region of the glass plate that overlaps the transparent region in a plan view. The dimming element includes a dimming element capable of switching the light transmittance, and the dimming element includes a dimming layer, a pair of conductive thin films sandwiching the dimming layer, and the pair of conductive thin films. A dimming bus bar that drives the dimming layer by energizing the light beam, and a heating bus bar that heats at least one of the pair of conductive thin films.

Description

The present invention relates to glass and laminated glass.

The vehicle has a see-through area on the glass for safety, so that the occupant can grasp the situation outside the vehicle, for example. Further, in recent years, for the purpose of improving the safety of the vehicle, a vehicle having a function of automatically avoiding a collision with a vehicle traveling ahead or a pedestrian has been developed. In such a vehicle, for example, a device such as a camera is mounted in the vehicle, and information such as a road condition is transmitted and received through the glass of the vehicle (for example, a windshield).

However, in the fluoroscopic region, it may be difficult to obtain information from the outside of the vehicle due to backlight or backlight from the headlights of an oncoming vehicle. Similarly, a device such as a camera may have difficulty in acquiring information from outside the vehicle due to sunlight or backlight from the headlight of an oncoming vehicle. Therefore, there has been proposed a technique of arranging a liquid crystal plate capable of changing the light transmittance for each region divided into a plurality of regions, that is, dimming, on the front surface of a device such as a camera. In this technology, anti-glare performance is achieved by averaging the difference in the amount of incident light generated between regions in the event of backlight or the like by dimming and leveling the brightness of the entire image of a device such as a camera (for example). , Patent Document 1).

Japanese Unexamined Patent Publication No. 9-24827

However, when the dimming element is applied to the glass of a vehicle, the response speed of the dimming element at a low temperature (for example, about -20 ° C.) decreases, so that on-demand antiglare performance cannot be achieved at a low temperature. ..

The present invention has been made in view of the above points, and an object of the present invention is to improve the response speed of a dimming element at a low temperature in a glass having a dimming element.

The present glass is glass for a vehicle, and is arranged in at least a part of a glass plate, a transparent region defined by the glass, and a region of the glass plate that overlaps the transparent region in a plan view. The dimming element comprises a dimming element capable of switching the light transmittance, and the dimming element energizes a dimming layer, a pair of conductive thin films sandwiching the dimming layer, and the pair of conductive thin films. It is a requirement that the light control bus bar for driving the light control layer and the heating bus bar for heating at least one of the pair of conductive thin films are included.

According to one embodiment of the disclosure, in a glass having a dimming element, the response speed of the dimming element at a low temperature can be improved.

It is a figure which illustrates the windshield for the vehicle which concerns on 1st Embodiment. It is a figure which illustrates the dimming element which concerns on 1st Embodiment. It is a top view which illustrates the light control element which concerns on the modification 1 of the 1st Embodiment. It is sectional drawing which illustrates the dimming element which concerns on the modification 2 of the 1st Embodiment. It is a figure which shows the cross-sectional structure of the laminated glass which concerns on a comparative example. It is a figure which shows the condition and result of an Example and a comparative example.

Hereinafter, modes for carrying out the invention will be described with reference to the drawings. In each drawing, the same components may be designated by the same reference numerals and duplicate description may be omitted. Further, in each drawing, the size and shape may be partially exaggerated so that the content of the present invention can be easily understood.

Although the windshield for a vehicle will be described as an example here, the present invention is not limited to this, and the glass according to the embodiment can be applied to other than the windshield for a vehicle. Further, although the information transmission / reception area will be described as an example of the fluoroscopic region, the present invention is not limited to this, and the fluoroscopic region refers to an region in which light is transmitted through the glass and the situation outside the vehicle can be grasped. Further, the vehicle is typically an automobile, but refers to a moving body having glass including a train, a ship, an aircraft, and the like.

Further, the plan view refers to viewing a predetermined region of the windshield from the normal direction of the predetermined region, and the planar shape refers to the shape of the predetermined region of the windshield viewed from the normal direction of the predetermined region. .. Further, in the specification of the present application, the top and bottom refer to the Z-axis direction of the drawing, and the left and right refer to the Y-axis direction of the drawing.

The visible light transmittance of the present invention is a value specified in JIS R3108: 1998.

The energy reflectance of the present invention is a value specified in JIS R3108: 1998.

<First Embodiment>
FIG. 1 is a diagram illustrating a windshield for a vehicle according to the first embodiment, and FIG. 1A is a diagram schematically showing a state in which the windshield is visually recognized from the inside of the vehicle to the outside of the vehicle. (The windshield 20 is attached to the vehicle with the Z direction facing upward). FIG. 1B is a cross-sectional view of the windshield 20 shown in FIG. 1A cut in the XZ direction and viewed from the Y direction. Although the device 300 is shown together with the windshield 20 in FIG. 1B for convenience, the device 300 is not a component of the windshield 20.

As shown in FIG. 1, the windshield 20 includes a glass plate 21 which is a glass plate inside the vehicle, a glass plate 22 which is a glass plate outside the vehicle 22, an interlayer film 23, a shielding layer 24, and a dimming element 25. It is a laminated glass for a vehicle.

In the windshield 20, the glass plate 21 and the glass plate 22 are fixed with the interlayer film 23 and the light control element 25 sandwiched between them. The interlayer film 23 may be formed from a plurality of layers of intermediate films. Details of the glass plate 21, the glass plate 22, and the interlayer film 23 will be described later.

The shielding layer 24 is provided on the peripheral edge of the vehicle inner surface 21a of the glass plate 21. The shielding layer 24 is an opaque layer, and can be formed by, for example, applying a printing ink of a predetermined color to a glass surface and baking the glass surface. The shielding layer 24 is, for example, an opaque (eg, black) colored ceramic layer. Since the opaque shielding layer 24 is present on the peripheral edge of the windshield 20, an adhesive member such as urethane that holds the peripheral edge of the windshield 20 on the vehicle body and a bracket that locks the device 300 are attached to the windshield 20. Deterioration of adhesive members due to ultraviolet rays can be suppressed.

In FIG. 1B, the shielding layer 24 is provided on the inner surface 21a of the glass plate 21, but the present invention is not limited to this. The shielding layer 24 may be provided, for example, on the vehicle inner surface of the glass plate 22, or may be provided on both the vehicle inner surface 21a of the glass plate 21 and the vehicle inner surface of the glass plate 22.

A test area A defined by JIS standard R3212 is defined on the windshield 20. Further, a perspective region, here, an information transmission / reception region 26, is defined on the windshield 20. The test area A is located inside the area surrounded by the shielding layer 24 in a plan view, and the information transmission / reception area 26 is located in the opening provided in the shielding layer 24.

The information transmission / reception area 26 functions as an area for transmitting and / or receiving information when the device 300 is arranged on the upper peripheral edge of the windshield 20 in the vehicle. The planar shape of the information transmission / reception area 26 is not particularly limited, but may be, for example, an isosceles trapezoid. The information transmission / reception area 26 may be located above the test area A because it does not obstruct the driver's field of vision when the windshield 20 is attached to the vehicle and is advantageous for transmitting and / or receiving information. preferable.

The device 300 is a device that transmits and / or receives information, and examples thereof include a camera that acquires visible light, infrared light, and the like, a millimeter wave radar, an infrared laser, and the like, and is typically a camera. .. In addition to the device 300, another device that transmits and / or receives information via the information transmission / reception area 26 may be arranged in the vehicle. Here, the "signal" refers to an electromagnetic wave including millimeter waves and light such as visible light and infrared light, and is typically visible light.

The dimming element 25 is arranged in at least a part of the area between the glass plate 21 and the glass plate 22 that is outside the test area A and overlaps with the information transmission / reception area 26 in a plan view. It is an element capable of switching the light transmittance of 26. If necessary, the dimming element 25 may be arranged inside the test region A in a plan view between the glass plate 21 and the glass plate 22.

The planar shape of the dimming element 25 is preferably, for example, a rectangle slightly larger than the planar shape of the information transmission / reception region 26, but it may be a trapezoid, or a rectangular shape or a shape in which any side of the trapezoid is curved. Or other shapes. The planar shape of the dimming element 25 may be smaller than the planar shape of the information transmission / reception region 26.

FIG. 2 is a diagram illustrating a dimming element according to the first embodiment, and FIG. 2A is a plan view schematically showing a state in which the vicinity of the information transmission / reception region is visually recognized from the inside of the vehicle to the outside of the vehicle. 2 (b) is a cross-sectional view taken along the line AA of FIG. 2 (a). In FIG. 2A, the glass plates 21 and 22, the interlayer film 23, and the shielding layer 24 are not shown. Further, in FIG. 2A, the information transmission / reception area 26 is shown by a broken line for convenience.

The dimming element 25 is enclosed in an interlayer film 23, and includes a base material 251, a conductive thin film 252, a dimming layer 253, a conductive thin film 254, a base material 255, a heating bus bar 256, and dimming. It is equipped with a bus bar 257 for use.

As the base materials 251 and 255, for example, transparent resin or glass can be used. The thicknesses of the base materials 251 and 255 can be 5 μm or more and 500 μm or less, preferably 10 μm or more and 200 μm or less, and more preferably 50 μm or more and 150 μm or less.

The plastic films used as the base materials 251 and 255 include, for example, polyester (for example, polyethylene terephthalate, polyethylene naphthalate, etc.), polyamide, polyether, polysulphon, polyether sulphon, polycarbonate, polyarylate, polyetherimide, polyether ether. It can be formed from a homopolymer or copolymer of at least one monomer selected from the group consisting of ketones, polyimides, aramids, polybutylene terephthalates, polyvinyl butyral, polyethyl vinyl acetate. Examples of the glass material used as the base materials 251 and 255 include soda lime glass, inorganic glass such as aluminosilicate, and organic glass.

The conductive thin film 252 is formed on the surface of the base material 251 on the glass plate 21 side, and is in contact with the surface of the light control layer 253 on the glass plate 22 side. The conductive thin film 254 is formed on the surface of the base material 255 on the glass plate 22 side, and is in contact with the surface of the light control layer 253 on the glass plate 21 side. That is, the conductive thin films 252 and 254 are a pair of conductive thin films that sandwich the dimming layer 253.

As the conductive thin films 252 and 254, for example, transparent conductive oxide (TCO) can be used. Examples of TCO include, but are not limited to, tin-doped indium oxide (ITO), aluminum-doped zinc oxide (AZO), indium-added cadmium oxide, and the like.

As the conductive thin films 252 and 254, transparent conductive polymers such as poly (3,4-ethylenedioxythiophene) (PEDOT) or poly (4,4-dioctylcyclopentadithiophene) can also be preferably used. Further, as the conductive thin films 252 and 254, a laminated film of a metal layer and a dielectric layer, silver nanowires, a metal mesh of silver or copper and the like can also be preferably used.

The conductive thin films 252 and 254 can be formed by using, for example, a physical vapor deposition method (PVD: Physical Vapor Deposition) such as a sputtering method, a vacuum vapor deposition method, or an ion plating method. The conductive thin films 252 and 254 may be formed by using a chemical vapor deposition (CVD) method or a wet coating method.

By the way, when the dimming element 25 is applied to the windshield 20, it is necessary to prevent the dimming element 25 from being deteriorated due to high temperature due to heat rays from the sun. In order to realize this, for example, it is conceivable to use the light control element 25 together with the heat ray reflecting glass or the heat ray reflecting film. In this case, if the heat ray reflecting glass is applied only to the vicinity of the information transmission / reception region 26, the cost becomes high, so it is preferable to use the heat ray reflecting film which is relatively low cost. However, if a heat ray reflecting film is used, the transmittance of the windshield 20 may decrease or the color of the windshield 20 may change due to the addition of the heat ray reflecting film, which may hinder the sensing performance of the device 300. There is.

In the windshield 20, the heat ray reflecting layer is not provided separately from the light control element 25, but the conductive thin film 252 and / or the conductive thin film 254 for energizing the light control layer 253 is provided with the function of the heat ray reflecting layer. be able to. In this case, the influence on the sensing performance of the device 300 can be reduced as compared with the case where the heat ray reflecting layer is provided separately from the light control element 25. That is, it is possible to suppress changes in the dimming element 25 due to heat rays while maintaining the sensing performance of the device 300. Specifically, as compared with the case where the heat ray reflecting layer is provided separately from the light control element 25, the visible light transmittance of the portion of the front glass 20 in which the light control element 25 is enclosed is lowered and the color is changed in the light transmission mode. Can be suppressed.

Here, the color change is defined by the difference between the maximum value and the minimum value of the transmittance at a predetermined wavelength (436 nm, 546 nm, 700 nm), and the maximum value and the minimum value of the transmittance at a predetermined wavelength (436 nm, 546 nm, 700 nm). If the difference between the two is 12% or less, it is considered to be within the permissible range. The predetermined wavelengths (436 nm, 546 nm, 700 nm) are wavelengths corresponding to blue-green-red of the RGB color system defined by the CIE (International Commission on Illumination), and the difference in transmittance between the three wavelengths is larger than 12%. It adversely affects the sensing performance of the device 300.

In order to prevent the dimming element 25 from deteriorating due to high temperature due to heat rays, the conductive thin film 252 and / or the conductive thin film 254 can be provided with the function of a heat ray reflecting layer, but at least on the outside of the vehicle. It is preferable that the conductive thin film 252 to be arranged has a heat ray reflecting function. As a result, it is possible to effectively prevent the dimming element 25 from becoming hot due to heat rays, and it is possible to prevent the dimming element 25 from deteriorating. Further, the energy reflectance of the information transmission / reception region 26 is preferably 25% or more. As a result, it is possible to effectively prevent the dimming element 25 from becoming hot due to heat rays, and it is possible to prevent the dimming element 25 from deteriorating.

When the conductive thin film 252 and / or the conductive thin film 254 has the function of a heat ray reflecting layer, any of the materials exemplified above can be used as the material of the conductive thin film 252 and / or the conductive thin film 254. ..

However, as the conductive thin film 252 and / or the conductive thin film 254, an n-layer (n is an integer of 2 or more) functional layer containing a material that reflects infrared rays and an n + 1 layer dielectric laminated so as to sandwich the functional layer. It is preferable to use a laminated film having a body layer. By using such a laminated film as the conductive thin film 252 and / or the conductive thin film 254, it is possible to increase the energy reflectance of the information transmission / reception region 26 (for example, 25% or more), and the dimming element 25 The effect of suppressing deterioration can be improved.

For example, silver is used as a material that reflects infrared rays, and a laminated film having two functional layers containing silver and three dielectric layers laminated so as to sandwich the functional layers, or a three-layer function containing silver. A laminated film having a layer and four dielectric layers laminated so as to sandwich the functional layer can be used.

When the material that reflects infrared rays is silver, the functional layer containing silver may be formed only from silver, or may be a metal layer or an alloy layer containing silver as a main component. When silver is the main component, for example, Pd, Au, Cu, Pt and the like may be contained as a metal element other than silver. The film thickness of the functional layer and the dielectric layer can be appropriately determined depending on the total number of layers and the constituent materials of each layer, and can be, for example, about several nm to several hundred nm.

The dimming layer 253 is sandwiched between the conductive thin film 252 and the conductive thin film 254. As the dimming layer 253, for example, a Suspended Particle Device (SPD) film can be used. The SPD film is a general SPD film in which a polymer layer containing suspended particles that can be oriented by applying a voltage is sandwiched between two electrically insulating films coated with a transparent conductive film on the inside. Film is available. Such an SPD film has high visible light transmittance and high transparency by orienting suspended particles in the polymer layer by turning on the power switch and applying a voltage between the transparent conductive films. become. When the power switch is off, the suspended particles in the polymer layer are not oriented, the visible light transmittance is low, and the transparency is low.

As the dimming layer 253, a polymer-dispersed liquid crystal display (PDLC) may be used instead of the SPD film. The PDLC film can be made by mixing a prepolymer, a nematic liquid crystal, and a spacer material in a specific ratio, and then placed between two soft transparent conductive films. The operating principles include: In the absence of an electric field, the liquid crystal droplets can be randomly distributed in the polymeric material with their orientators freely oriented. In such cases, the index of refraction of the liquid crystal with respect to normal light does not match that of the polymeric material, causing a relatively strong scattering effect with respect to light, resulting in a translucent or opaque "milky white" appearance of the PDLC film. Become. Under an electric field, the liquid crystal droplets can be aligned along the direction of the external electric field due to their positive permittivity anisotropic properties. If the index of refraction of the liquid crystal with respect to normal light matches that of the polymeric material, the light can pass through the PDLC film and thus the PDLC film will have a transparent appearance. Specifically, the higher the voltage supplied to the PDLC film, the more transparent the PDLC film becomes.

Further, as the dimming layer 253, a polymer network type liquid crystal display (PNLC), a guest host type liquid crystal display, a TN type liquid crystal display, a VA type liquid crystal display, a photochromic, an electrochromic, an electrokinetic or the like may be used.

Further, it is more desirable to use a light control layer 253 in which the oriented particles stand perpendicular to the transparent conductive film when no voltage is applied. Such a light control layer transmits light when no electric field is applied, and when a voltage is applied, the oriented particles lie down and can absorb or scatter the light. Such a dimming mode is called a reverse mode, and can be realized by a liquid crystal material having a negative dielectric constant anisotropic characteristic.

When the dimming element 25 is arranged in the transparent area of the window glass of the vehicle, it is more desirable to apply the dimming element 25 in the reverse mode in consideration of the risk of disconnection failure due to the impact of the accident.

The pair of heating bus bars 256 extend in the Z direction along both ends of the surface of the conductive thin film 252 on the glass plate 21 side in the Y direction, and are arranged so as to face each other with the dimming layer 253 in between. The pair of heating bus bars 256 are electrically connected to the conductive thin film 252 and heat the conductive thin film 252.

One pole of the pair of heating bus bars 256 is, for example, a positive electrode, and is connected to the positive side of a power source such as a battery mounted on a vehicle via a lead wire or the like. Further, the other electrode of the pair of heating bus bars 256 is, for example, a negative electrode, and is connected to the negative side of a power source such as a battery mounted on a vehicle via a lead wire or the like.

When an electric current is supplied to the conductive thin film 252 from a power source such as a battery via a pair of heating bus bars 256, the conductive thin film 252 generates heat. Since the heat generated by the conductive thin film 252 heats the dimming layer 253, it is possible to prevent a decrease in the response speed of the dimming element 25 at a low temperature (for example, the temperature outside the vehicle is about -20 ° C), and even at a low temperature. Achieves on-demand anti-glare performance.

Further, the heat generated in the conductive thin film 252 warms the information transmission / reception region 26 of the windshield 20, removes freezing and fogging of the surfaces of the glass plates 21 and 22 constituting the information transmission / reception region 26, and good sensing by the device 300. Can be secured.

The amount of heat generated by the conductive thin film 252 heated by the heating bus bar 256 ^{is preferably 600 W / m 2} or more. It is more preferably 800 W / m ² or more, and more preferably 1000 W / m ² or more. As a result, it is possible to effectively prevent a decrease in the response speed of the dimming element 25 at a low temperature. Further, the performance of removing freezing and fogging on the surfaces of the glass plates 21 and 22 constituting the information transmission / reception region 26 is improved, and better sensing by the device 300 can be ensured.

Further, the heating of the conductive thin film 252 can be effectively controlled by sensing the outside air temperature. For example, when the outside air temperature is higher than 5 ° C., the response speed of the dimming element 25 does not decrease so much that the conductive thin film 252 is not heated, but when the outside air temperature falls below 5 ° C., the dimming element 25 is heated. It can be controlled to prevent a decrease in response speed. As a result, not only unnecessary power consumption when the outside air temperature is high can be suppressed, but also when the outside air temperature is high, the interlayer film 23 and the dimming element 25 become excessively high in temperature due to the heat generated by the conductive thin film 252 and deteriorate. It can also be prevented.

The pair of heating bus bars 256 may be electrically connected to the conductive thin film 254 instead of the conductive thin film 252. In this case, the conductive thin film 254 can be heated. Further, the pair of heating bus bars 256 may be electrically connected to the conductive thin film 252, and the other pair of heating bus bars may be electrically connected to the conductive thin film 254. In this case, since the conductive thin films 252 and 254 can be heated, the total calorific value can be increased.

Although not appearing in the cross section of FIG. 2B, the pair of dimming bus bars 257 extend in the Y direction along one end of the surface of the conductive thin film 252 on the glass plate 21 side in the Z direction. One of the pair of dimming bus bars 257 is electrically connected to the conductive thin film 252, and the other is electrically connected to the conductive thin film 254, and the conductive thin films 252 and 254 are energized to energize the dimming layer 253. To drive. The pair of dimming bus bars 257 are independent of the pair of heating bus bars 256.

One pole of the pair of dimming bus bars 257 is, for example, a positive electrode, and is connected to the positive side of a power source such as a battery mounted on a vehicle via a lead wire or the like. Further, the other pole of the pair of dimming bus bars 257 is, for example, a negative electrode, which is connected to the negative side of a power source such as a battery mounted on a vehicle via a lead wire or the like.

When a voltage is supplied to the dimming layer 253 from a power source such as a battery via a pair of dimming bus bars 257, the transmittance of the dimming layer 253 is switched according to the voltage.

A silver paste is preferably used as the heating bus bar 256 and the dimming bus bar 257. The silver paste can be applied by a printing method such as screen printing. The heating bus bar 256 and the dimming bus bar 257 are at least one metal selected from the group consisting of silver, copper, tin, gold, aluminum, iron, tungsten and chromium, and two or more metals selected from this group. It may be formed from an alloy containing, or a conductive organic polymer by a sputtering method or the like. Further, as the heating bus bar 256 and the dimming bus bar 257, a copper ribbon, a flat braided copper wire, or a copper tape having a conductive adhesive may be used.

The dimming element 25 has a light transmission mode (mode having high visible light transmittance) and a light absorption mode (mode having low visible light transmittance). The maximum visible light transmittance of the information transmission / reception region 26 including the dimming element 25 in the light transmission mode is within an allowable range if it is 40% or more, but is preferably 50% or more. By setting the maximum visible light transmittance of the information transmission / reception region 26 including the dimming element 25 in the light transmission mode to 50% or more, good sensing by the device 300 can be sufficiently ensured. The maximum visible light transmittance means the visible light transmittance in a state where the voltage applied to the dimming layer 253 is adjusted so that the visible light transmittance is maximized.

For example, when the dimming element 25 is in the light transmission mode when energized, it is preferable that the maximum visible light transmittance can be 50% or more when energized. In this case, it is more preferable that the maximum visible light transmittance can be 60% or more, and even more preferably 70% or more when energized. Further, when the light control element 25 is in the light absorption mode when it is not energized, it is preferable that the visible light transmittance can be less than 20% when it is not energized. Further, it is desirable that the visible light transmittance is 5% or more. This is because if it is less than 5%, it becomes difficult to recognize the situation outside the vehicle.

The dimming element 25 may be in the light transmission mode when it is not energized. In this case, the control of energization / de-energization may be reversed. Also in this case, the maximum visible light transmittance of the information transmission / reception region 26 including the dimming element 25 in the light transmission mode is preferably 50% or more, more preferably 60% or more, and further 70% or more. Preferably, the minimum visible light transmittance in the light absorption mode is 5% or more.

Since the windshield 20 has the dimming element 25, the amount of light transmitted through the information transmission / reception region 26 can be adjusted according to the amount of light incident on the information transmission / reception region 26 from outside the vehicle. For example, when the amount of incident light is excessive due to direct sunlight, the headlight of an oncoming vehicle, or the like, the visible light transmittance is lowered to reduce the amount of light transmitted in the information transmission / reception region 26, and the device 300 The amount of light incident on the can be adjusted to an appropriate amount. When the amount of light incident on the information transmission region is not excessive, the visible light transmittance in the low transmission region is changed to a high value so that the light can be sufficiently transmitted in the information transmission / reception region 26 and is incident on the device. The amount of light can be adjusted to an appropriate amount.

It is preferable that the windshield 20 further has a control device that measures the amount of light incident on the information transmission / reception region 26 from the outside of the vehicle and controls the energization and de-energization of the dimming element 25 according to the amount of light. For example, when a dimming element having a high visible light transmittance is used as the dimming element 25, the power is kept on when the amount of incident light is not excessive by using such a control device. However, the power can be turned off when the amount of incident light is excessive due to backlight or the like. As a result, the amount of light transmitted through the information transmission / reception region 26 can be optimized at all times, and the amount of light incident on the device 300 can be set to an appropriate amount. When the dimming element 25 having a high visible light transmittance at the time of non-energization is used, the same effect can be expected by reversing the control of energization / non-energization.

Here, the glass plate 21, the glass plate 22, and the interlayer film 23 will be described in detail.

In the windshield 20, the inner surface 21a of the glass plate 21 (inner surface of the windshield 20) and the outer surface 22a of the glass plate 22 (outer surface of the windshield 20) are curved surfaces even if they are flat. It doesn't matter if there is.

As the glass plates 21 and 22, for example, soda lime glass, inorganic glass such as aluminosilicate, organic glass and the like can be used. When the glass plates 21 and 22 are inorganic glass, they can be produced by, for example, the float method.

The thickness of the glass plate 22 located on the outside of the windshield 20 is preferably 1.8 mm or more and 3 mm or less at the thinnest portion. When the thickness of the glass plate 22 is 1.8 mm or more, the strength such as stepping stone resistance is sufficient, and when it is 3 mm or less, the mass of the laminated glass does not become too large, which is preferable in terms of fuel efficiency of the vehicle. The thinnest portion of the glass plate 22 is more preferably 1.8 mm or more and 2.8 mm or less, and further preferably 1.8 mm or more and 2.6 mm or less.

The thickness of the glass plate 21 located inside the windshield 20 is preferably 0.3 mm or more and 2.3 mm or less. When the thickness of the glass plate 21 is 0.3 mm or more, the handleability is good, and when it is 2.3 mm or less, the mass of the windshield 20 does not become too large. The glass plate 21 and the glass plate 22 may have a wedge-shaped cross section.

However, the plate thicknesses of the glass plates 21 and 22 are not always constant, and may change from place to place as needed. For example, one or both of the glass plates 21 and 22 may have a cross-sectional wedge-shaped region in which the thickness of the upper end side in the vertical direction when the windshield 20 is attached to the vehicle is thicker than that of the lower end side.

When the windshield 20 has a curved shape, the glass plates 21 and 22 are bent and molded after being molded by the float method or the like and before being bonded by the interlayer film 23. Bending molding is performed by softening the glass by heating. The heating temperature of the glass during bending is approximately 550 ° C to 700 ° C.

A thermoplastic resin is often used as the interlayer film 23 for adhering the glass plate 21 and the glass plate 22, and for example, a plasticized polyvinyl acetal resin, a plasticized polyvinyl chloride resin, a saturated polyester resin, and a plasticized saturated polyester. Examples thereof include thermoplastic resins conventionally used in this type of application, such as based resins, polyurethane resins, plasticized polyurethane resins, ethylene-vinyl acetate copolymer resins, and ethylene-ethyl acrylate copolymer resins. Further, the resin composition containing the modified block copolymer hydride described in Japanese Patent No. 6065221 can also be preferably used.

Among these, plasticized polyvinyl acetal-based resins have an excellent balance of various performances such as transparency, weather resistance, strength, adhesive strength, penetration resistance, impact energy absorption, moisture resistance, heat insulation, and sound insulation. Is preferably used. These thermoplastic resins may be used alone or in combination of two or more. "Plasticization" in the above-mentioned plasticized polyvinyl acetal-based resin means that it is plasticized by adding a plasticizer. The same applies to other thermoplastic resins.

The polyvinyl acetal resin is a polyvinyl formal resin obtained by reacting polyvinyl alcohol (hereinafter, may also be referred to as “PVA” if necessary) with formaldehyde, and a narrow sense obtained by reacting PVA with acetaldehyde. Polyvinyl butyral resin obtained by reacting PVA with n-butylaldehyde (hereinafter, may be referred to as "PVB" if necessary), etc., and in particular, transparency and weather resistance. PVB is preferable because it has an excellent balance of various performances such as strength, adhesive strength, penetration resistance, impact energy absorption, moisture resistance, heat insulation, and sound insulation. These polyvinyl acetal-based resins may be used alone or in combination of two or more. However, the material forming the interlayer film 23 is not limited to the thermoplastic resin. Further, the interlayer film 23 may contain functional particles such as an infrared absorber, an ultraviolet absorber, and a luminescent agent.

The film thickness of the interlayer film 23 is preferably 0.5 mm or more at the thinnest portion. When the film thickness of the interlayer film 23 is 0.5 mm or more, the penetration resistance required for the windshield is sufficient. Further, the film thickness of the interlayer film 23 is preferably 3 mm or less at the thickest portion. When the maximum value of the film thickness of the interlayer film 23 is 3 mm or less, the mass of the laminated glass does not become too large. The maximum value of the interlayer film 23 is more preferably 2.8 mm or less, further preferably 2.6 mm or less. Further, the interlayer film 23 may have a wedge shape in cross section.

The interlayer film 23 may have three or more layers. For example, the sound insulation of the laminated glass can be improved by forming the interlayer film from three layers and lowering the hardness of the middle layer to be lower than the hardness of the layers on both sides by adjusting a plasticizer or the like. In this case, the hardness of the layers on both sides may be the same or different.

In order to produce the interlayer film 23, for example, the above resin material to be an interlayer film is appropriately selected and extruded in a heat-melted state using an extruder. The extrusion conditions such as the extrusion speed of the extruder are set to be uniform. After that, the interlayer film 23 is completed by extending the extruded resin film, for example, as necessary, in order to give curvature to the upper side and the lower side according to the design of the windshield 20.

In order to produce laminated glass, an interlayer film 23 and a dimming element 25 are sandwiched between the glass plate 21 and the glass plate 22 to form a laminated body. Then, for example, this laminate is placed in a rubber bag and bonded at a temperature of about 70 to 110 ° C. in a vacuum of −65 to −100 kPa. The heating conditions, temperature conditions, and laminating method are appropriately selected in consideration of the properties of the dimming element so as not to deteriorate during laminating, for example.

Further, for example, by performing a pressure bonding process of heating and pressurizing under the conditions of 100 to 150 ° C. and a pressure of 0.6 to 1.3 MPa, a laminated glass having more excellent durability can be obtained. However, in some cases, this heating and pressurizing step may not be used in consideration of the simplification of the step and the characteristics of the material to be sealed in the laminated glass.

Between the glass plate 21 and the glass plate 22, in addition to the interlayer film 23 and the dimming element 25, there are functions such as light emission, visible light reflection, scattering, decoration, and absorption as long as the effects of the present application are not impaired. You may have a film or device. The functional film and device may be formed directly on the main surfaces of the glass plate 21 and the glass plate 22.

As described above, the windshield 20 has a dimming element 25. The dimming element 25 is a dimming bus bar 257 that drives the dimming layer 253 by energizing the dimming layer 253, the conductive thin films 252 and 254 sandwiching the dimming layer 253, and the conductive thin films 252 and 254. And a heating bus bar 256 for heating the conductive thin film 252.

As a result, the conductive thin film 252 can be heated via the heating bus bar 256, so that the temperature of the dimming layer 253 can be made higher than the temperature outside the vehicle even when the temperature outside the vehicle is low. As a result, even when the outside temperature of the vehicle becomes low, it is possible to prevent a decrease in the response speed of the dimming element 25, and on-demand anti-glare performance can be achieved.

Further, in the windshield 20, it is preferable that the conductive thin film 252 and / or the conductive thin film 254 has the function of a heat ray reflecting layer. As a result, even if a heat ray reflecting layer is not provided separately from the light control element 25, it is possible to reduce the possibility that the light control element 25 becomes hot due to heat rays while maintaining the sensing performance of the device 300, and the light control element 25 deteriorates. It is possible to prevent the risk of Further, in this case, as compared with the case where the heat ray reflecting layer is provided separately from the light control element 25, the visible light transmittance of the portion of the front glass 20 in which the light control element 25 is enclosed is lowered and the color is changed in the light transmission mode. Can be suppressed.

<Modification 1 of the first embodiment>
A modification 1 of the first embodiment shows an example in which one of the heating bus bars also serves as a dimming bus bar. In the first modification of the first embodiment, the description of the same component as that of the above-described embodiment may be omitted.

FIG. 3 is a plan view illustrating the dimming element according to the first modification of the first embodiment, and schematically shows a state in which the vicinity of the information transmission / reception region is visually recognized from the inside of the vehicle to the outside of the vehicle. Since the cross-sectional structure of the dimming element according to the first modification of the first embodiment is the same as that shown in FIG. 2B, the illustration is omitted.

As shown in FIG. 3, in the windshield 20A according to the first modification of the first embodiment, the dimming element 25A has only one dimming bus bar 257 electrically connected to the conductive thin film 254. Have. Other points of the dimming element 25A are the same as those of the dimming element 25.

Since the heating bus bar 256 is electrically connected to the conductive thin film 252, when a voltage is applied between either one of the heating bus bars 256 and the dimming bus bar 257, the dimming layer 253 responds to the voltage. The transmittance of the can be switched. That is, in the dimming element 25A, one of the heating bus bars 256 also serves as the dimming bus bar 257.

As described above, since one of the heating bus bars 256 also serves as the dimming bus bar 257, the structure of the dimming element 25A can be simplified as compared with the structure of the dimming element 25.

<Modification 2 of the first embodiment>
In the second modification of the first embodiment, an example in which the windshield is not a laminated glass is shown. This embodiment is suitable as a side glass and a rear glass, but will be described here as an embodiment as a windshield. In the second modification of the first embodiment, the description of the same component as that of the above-described embodiment may be omitted.

FIG. 4 is a cross-sectional view illustrating the dimming element according to the second modification of the first embodiment, and shows a cross section corresponding to FIG. 2 (b). In addition, in the modified example 2 of the first embodiment, the plan view schematically showing the state in which the vicinity of the information transmission / reception area is visually recognized from the inside of the vehicle to the outside of the vehicle is the same as that of FIG. Omit.

As shown in FIG. 4, the windshield 20B is a glass for a vehicle (not a laminated glass), and has a glass plate 22, a light control element 25, and an adhesive layer 27. The light control element 25 is fixed to the vehicle inner surface 22b of the glass plate 22 by the adhesive layer 27.

The material of the adhesive layer 27 is not particularly limited as long as it has a function of fixing the light control element 25, and is, for example, acrylic, acrylate, urethane, urethane acrylate, epoxy, epoxy acrylate, or polyolefin. , Modified olefin-based, polypropylene-based, ethylene vinyl alcohol-based, vinyl chloride-based, chloroprene rubber-based, cyanoacrylate-based, polyamide-based, polyimide-based, polystyrene-based, polyvinyl butyral-based materials. The material of the adhesive layer 27 is transparent to visible light. The thickness of the adhesive layer 27 can be, for example, 0.2 μm or more and 70 μm or less.

As described above, even when the windshield 20B is not a laminated glass, the dimming element 25 has a heating bus bar 256 for heating the conductive thin film 252 in addition to the dimming bus bar 257 for driving the dimming layer 253. As a result, the same effect as that of the first embodiment is obtained. Further, by giving the conductive thin film 252 and / or the conductive thin film 254 the function of the heat ray reflecting layer, the same effect as that of the first embodiment can be obtained.

<Examples and Comparative Examples>
[Example 1]
In Example 1, a laminated glass provided with the dimming element 25 shown in FIG. 2 was produced. Specifically, clear glass having a plate thickness of 2 mm was used as the glass plates 21 and 22, and a flat plate having a size of 150 mm × 150 mm was used. As the interlayer film 23, PVB having a thickness of 0.38 mm was used.

As the dimming element 25, SPD-A has the same configuration as LCF-1103DHA (manufactured by Hitachi Kasei Co., Ltd., thickness 30 μm). Specifically, the base material 251 formed by the sputtering method of ITO as the conductive thin film 252 and the base material 255 formed by the sputtering method of ITO as the conductive thin film 254 are formed, and the conductive thin films 252 and 254 form the dimming layer 253. The dimming element 25 was manufactured by arranging the elements so as to sandwich the light control element 25.

The calorific value of the conductive thin film 252 connected to the heating bus bar 256 was set to 800 [W / m ² ]. Further, the energy reflectance of the portion of the laminated glass in which the dimming element 25 is enclosed in this configuration is 6 [%].

[Example 2]
In Example 2, Ag3 was used as the conductive thin film 252. The calorific value of the conductive thin film 252 connected to the heating bus bar 256 was set to 1000 [W / m ² ]. Further, the energy reflectance of the portion of the laminated glass in which the dimming element 25 is enclosed in this configuration is 35 [%]. Other than that, a laminated glass was produced in the same manner as in Example 1. In addition, Ag3 is obtained by alternately sputtering three functional layers containing silver and four layers of dielectric layers of oxide containing zinc and tin as main components laminated so as to sandwich the functional layers. It is a laminated film.

[Example 3]
In Example 3, Ag2 was used as the conductive thin film 252. The calorific value of the conductive thin film 252 connected to the heating bus bar 256 was set to 600 [W / m ² ]. Further, the energy reflectance of the portion of the laminated glass in which the dimming element 25 is enclosed in this configuration is 25 [%]. Other than that, a laminated glass was produced in the same manner as in Example 1. In addition, Ag2 is obtained by alternately sputtering two functional layers containing silver and three layers of dielectric layers of an oxide containing zinc and tin as main components laminated so as to sandwich the functional layers. It is a laminated film.

[Example 4]
In Example 4, as the dimming element 25, SPD-B had the same configuration as LCF-1103DHA (manufactured by Hitachi Kasei Co., Ltd., thickness 90 μm). Specifically, the base material 251 formed by the sputtering method of ITO as the conductive thin film 252 and the base material 255 formed by the sputtering method of ITO as the conductive thin film 254 are formed, and the conductive thin films 252 and 254 form the dimming layer 253. The dimming element 25 was manufactured by arranging the elements so as to sandwich the light control element 25. Other than that, a laminated glass was produced in the same manner as in Example 1.

[Comparative Example 1]
In Comparative Example 1, the heating bus bar was not provided. Other than that, a laminated glass was produced in the same manner as in Example 1.

[Comparative Example 2]
In Comparative Example 2, as shown in FIG. 5, a laminated glass in which a heat ray reflecting film 35 having Ag3 formed as a heat ray reflecting layer 352 on the base material 351 is sealed on the outside of the vehicle than the light control element 25 of the interlayer film 23 is formed. Made. Further, the energy reflectance of the portion of the laminated glass in which the dimming element 25 is enclosed in this configuration is 35 [%]. Other than that, a laminated glass was produced in the same manner as in Example 1.

[Comparative Example 3]
In Comparative Example 3, the calorific value of the conductive thin film 252 connected to the heating bus bar 256 was set to 500 [W / m ² ]. Other than that, a laminated glass was produced in the same manner as in Example 1.

[evaluation]
First, the laminated glass was placed in a low temperature environment of −20 ° C., and the response speed of the dimming element 25 at a low temperature was evaluated. Here, the response speed means that when the difference between the transmittances of the light transmission mode and the light absorption mode in the light control element 25 is 100, the transmittance changes by 50% when the light absorption mode is changed to the light transmission mode. It is the time required for. If the response speed was less than 3 seconds, it was evaluated as 〇, and if it was 3 seconds or more, it was evaluated as x.

Secondly, the deterioration suppression of the dimming element 25 was evaluated. Specifically, with a super xenon weather meter, ultraviolet rays are emitted to the portion of the laminated glass in which the dimming element 25 is enclosed under the conditions of an ^{ultraviolet irradiance of 180 W / m 2 (300 to 400 nm) and a black panel temperature (BPT) of 63 ° C.} A test of irradiating for 3000 hours was performed. After the test, the transmittance retention rate (ratio of transmittance in the light transmission mode before and after the test) of the light control element 25 in the light transmission mode is measured, and if the retention rate is 90% or more, ⊚, 80% or more and 90%. If it is less than 80%, it is evaluated as ◯, and if it is less than 80%, it is evaluated as ×.

Third, the visible light transmittance (Tv) of the dimming element 25 in the light transmission mode is evaluated, and if the maximum visible light transmittance is 60% or more, ⊚, if 50% or more and less than 60%, ◯, If it was 40% or more and less than 50%, it was evaluated as Δ, and if it was less than 40%, it was evaluated as ×.

Fourth, the change in color of the dimming element 25 in the light transmission mode was evaluated. The color change is defined by the transmittance at a predetermined wavelength (436 nm, 546 nm, 700 nm), and if the difference between the maximum and the minimum transmittance at a predetermined wavelength (436 nm, 546 nm, 700 nm) is 12% or less, ○, 12%. If it is larger, it is marked as x.

The conditions and results of Examples and Comparative Examples are summarized in FIG. In any evaluation, "x" indicates an unfavorable state. Further, "△", "○", and "◎" all indicate preferable states, but "○" is preferable to "△", and "◎" is more preferable to "○". preferable.

As shown in FIG. 6, regarding the response speed of the dimming element 25 at a low temperature (-20 ° C.), the conductive thin film 252 is provided with a heating bus bar 256, and the conductive thin film 252 has a calorific value of 600 [W / m]. ^It can be seen that the decrease can be suppressed by heating to 2] or more. In addition, 600 [W / m ² ] is a sufficient amount of heat to clear the fogging of the laminated glass and to eliminate the freezing of the moisture adhering to the window glass in winter.

On the other hand, in Comparative Example 1, since the heating bus bar is not provided and the conductive thin film 252 cannot be heated, the response speed of the dimming element 25 at a low temperature (-20 ° C.) is lowered. Further, in Comparative Example 3, although the heating bus bar is provided, the calorific value of the conductive thin film 252 ^{is less than 600 [W / m 2} ], which is insufficient, so that the light is dimmed at a low temperature (-20 ° C). The response speed of the element 25 is slowing down.

Regarding the suppression of deterioration of the dimming element 25, the retention rate of the transmittance of the dimming element 25 in the light transmission mode is 80% or more, which is within an allowable range. However, when Ag2 or Ag3 is used as the heat ray reflecting layer (when the energy reflectance of the portion of the laminated glass in which the dimming element 25 is enclosed is 25 [%] or more), the effect of suppressing deterioration of the dimming element 25 is effective. Especially big.

The maximum visible light transmittance of the dimming element 25 in the light transmission mode is 40% or more, which is within an allowable range. In particular, when the conductive thin film 252 is Ag2, the light control element 25 is excellent in both performance of preventing a decrease in the response speed and suppressing deterioration, and also has the maximum visible light transmittance in the light transmission mode of the light control element 25. As for the rate, 60% or more can be secured, which can be said to be a preferable configuration.

The change in color of the light control element 25 in the light transmission mode is within the permissible range for Examples 1 to 4 and Comparative Examples 1 and 3. However, in Comparative Example 2, since the difference between the maximum value and the minimum value of the transmittance of the predetermined wavelength (436 nm, 546 nm, 700 nm) is larger than 12%, the sensing performance of the device 300 is adversely affected. That is, in the configuration in which the heat ray reflecting film is inserted separately from the light control element as in Comparative Example 2, the decrease in the response speed of the light control element 25 at a low temperature (-20 ° C) can be improved, but the sensing performance of the device 300 is improved. There is an adverse effect of inhibiting. Therefore, the configuration shown in FIG. 5 is not preferable.

Although the preferred embodiments and the like have been described in detail above, the embodiments are not limited to the above-described embodiments and the like, and various embodiments and the like described above are used without departing from the scope of the claims. Modifications and substitutions can be added.

This international application claims priority based on Japanese Patent Application No. 2018-168518 filed on September 10, 2018, and the entire contents of Japanese Patent Application No. 2018-168518 are incorporated into this international application. ..

20, 20A, 20B Windshield 21 Glass plate 21a, 22a, 22b Surface 22 Glass plate 23 Intermediate film 24 Shielding layer 25, 25A Dimming element 26 Information transmission / reception area 27 Adhesive layer 251, 255 Base material 252, 254 Conductive thin film 253 Dimming layer 256 Heating bus bar 257 Dimming bus bar

Claims (13)

It ’s a glass for cars,
With a glass plate
The fluoroscopic region defined in the glass and
The glass plate has a dimming element capable of switching the light transmittance, which is arranged in at least a part of a region overlapping the perspective region in a plan view.
The dimming element is
Dimming layer and
A pair of conductive thin films sandwiching the dimming layer,
A dimming bus bar that drives the dimming layer by energizing the pair of conductive thin films.
A glass comprising a heating bus bar that heats at least one of the pair of conductive thin films. The glass according to claim 1, wherein the fluoroscopic region is an information transmission / reception region in which a device mounted in a vehicle transmits and / or receives information. The dimming element has a light transmission mode and a light absorption mode.
The glass according to claim 1 or 2, wherein the maximum visible light transmittance of the transparent region including the dimming element in the light transmission mode is 50% or more. The glass according to claim 3, wherein the dimming element is in the light transmission mode when it is not energized. Of the pair of conductive thin films, at least the conductive thin film arranged on the outside of the vehicle has a heat ray reflecting function, and the energy reflectance in the see-through region is 25% or more, any one of claims 1 to 4. The glass described in. The glass according to any one of claims 1 to 5, wherein at least the conductive thin film arranged on the outside of the vehicle among the pair of conductive thin films contains silver. Of the pair of conductive thin films, at least the conductive thin film arranged on the outside of the vehicle sandwiches the functional layer of n layers (n is an integer of 2 or more) containing a material that reflects infrared rays. The glass according to any one of claims 1 to 6, further comprising an n + 1 layer of dielectric layers to be laminated. The glass according to any one of claims 1 to 7, wherein the pair of heating bus bars are arranged so as to face each other. The glass according to any one of claims 1 to 8, wherein the pair of dimming bus bars and the pair of heating bus bars are independent. The glass according to any one of claims 1 to 8, wherein one of the heating bus bars also serves as the dimming bus bar. The glass according to any one of claims 1 to 10, wherein the amount of heat generated by the conductive thin film heated by the heating bus bar is 600 W / m ^{2 or more.} The dimming element is any one of claims 1 to 11, which is any one of a TN type liquid crystal, a VA type liquid crystal, a guest host type liquid crystal, a polymer dispersion type liquid crystal, a polymer network type liquid crystal, and a suspended particle device. The glass described in. The glass according to any one of claims 1 to 12, an interlayer film, and a second glass plate are provided, and the glass plate and the second glass plate are bonded with the interlayer film interposed therebetween. Laminated glass for vehicles
A laminated glass in which the dimming element is enclosed in the interlayer film.

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