JP2018203608A - Glass laminae - Google Patents

Abstract

To cause reflection double image in a glass laminate having a wedge angle to be conspicuous, even when error of the wedge angle is generated.SOLUTION: The glass laminate has a first glass sheet which is an inner side of a vehicle, a second glass sheet which is an outer side of the vehicle, and an intermediate film positioned between the first glass sheet and the second glass sheet and adhering the first glass sheet and the second glass sheet, and having a display region used for a head up display, in which the display region has a wedge shaped region of thickness of an upper end side in a vertical direction is thicker than a lower end side when the glass laminate is attached to the vehicle, and a ratio Δt [mm] of thickness of the thickest location and the thinnest location of the display region and difference ΔTv [%] of visible light transmittance at the thickest location and the thinnest location satisfies a relationship of ΔTv≥2.2Δt.SELECTED DRAWING: Figure 9

Description

  The present invention relates to laminated glass.

  In recent years, the introduction of a head-up display (hereinafter also referred to as HUD) that reflects an image on a windshield of a vehicle and displays predetermined information in a driver's field of view is progressing. When viewing the information displayed by, double images may be a problem.

  There are two types of double images that are problematic for the driver of the vehicle: a perspective double image and a reflective double image. The HUD display area used in the HUD on the windshield and the HUD display outside area (transparent area) not used in the HUD are provided. In some cases, the perspective double image may be a problem in the HUD display area, but the reflection double image is a major problem in general, and the perspective double image is a problem in the HUD display outside area.

  It is known that such a reflection double image or a perspective double image can be reduced by using a laminated glass having a wedge-shaped cross section viewed from the horizontal direction on the windshield. For example, a laminated glass is proposed in which an interlayer film having a wedge-shaped cross section is sandwiched between two glass plates, and the wedge angle of the interlayer film is changed depending on the location of the windshield (see, for example, Patent Document 1).

JP-T-2017-502125

  However, it is difficult to precisely control the wedge angle regardless of whether a constant wedge angle region or a variable wedge angle region is provided on the windshield, and a certain error occurs in the wedge angle. Therefore, the reflected double image may not be sufficiently improved.

  The present invention has been made in view of the above points, and it is an object of the present invention to prevent a reflected double image from being noticeable even when a wedge angle error occurs in a laminated glass having a wedge angle.

  The laminated glass is positioned between the first glass plate that is the inside of the vehicle, the second glass plate that is the outside of the vehicle, and the first glass plate and the second glass plate. A laminated glass comprising an intermediate film for adhering the first glass plate and the second glass plate, comprising a display area used in a head-up display, wherein the display area comprises the laminated glass. The cross-sectional shape in which the thickness of the upper end side in the vertical direction when attached to the vehicle is thicker than the lower end side includes a wedge-shaped region, and the thickness difference Δt [mm] between the thickest portion and the thinnest portion of the display region And the difference ΔTv [%] in the visible light transmittance between the thickest portion and the thinnest portion of the display area satisfy the relationship ΔTv ≧ 2.2Δt.

  According to the disclosed technology, in a laminated glass having a wedge angle, a reflected double image can be made inconspicuous even when a wedge angle error occurs.

It is a figure explaining the concept of a double image. It is a figure explaining the windshield for vehicles. It is the fragmentary sectional view which cut the windshield 20 shown in FIG. 2 in the XZ direction, and was seen from the Y direction. It is sectional drawing which looked at the windshield 20 shown in FIG. 2 in the XZ direction, and was seen from the Y direction. It is a figure explaining the visible light transmittance | permeability of a laminated glass. It is a figure which illustrates the image of the brightness | luminance of a main image and a reflective double image. It is an example of the result of having measured the relationship between the total thickness of a laminated glass, and the visible light transmittance of a laminated glass. It is an example of the change of the visible light transmittance | permeability of a laminated glass when any one of the glass plate 220 or the intermediate film 230 is made into a wedge shape. It is a figure which illustrates about the relationship between thickness difference (DELTA) t and visible light transmittance | permeability difference (DELTA) Tv.

  Hereinafter, embodiments for carrying out the invention will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and redundant description may be omitted.

[Reflective double image, Transparent double image]
First, the concept of a reflection double image and a perspective double image will be described. 1A and 1B are diagrams for explaining the concept of a double image. FIG. 1A shows a reflection double image, and FIG. 1B shows a perspective double image. In FIG. 1, the front-rear direction of the vehicle on which the windshield 20 is mounted is X, the left-right direction of the vehicle is Y, and the direction perpendicular to the XY plane is Z (the same applies to the following drawings).

  As shown in FIG. 1A, a part of the light beam 11a emitted from the HUD light source 10 is reflected by the inner surface 21 of the windshield 20 of the vehicle to generate a light beam 11b (primary beam) of the driver's eyes 30. And is viewed by the driver as an image 11c (virtual image) in front of the windshield 20.

  Further, a part of the light beam 12 a emitted from the HUD light source 10 enters the inside from the inner surface 21 of the vehicle windshield 20 and is refracted, and a part thereof is reflected by the outer surface 22. Further, a part of the light exits from the inner surface 21 to the outside of the windshield 20 of the vehicle and is refracted and guided to the driver's eye 30 as a light beam 12b (secondary beam) and visually recognized by the driver as an image 12c (virtual image). Is done.

  Thus, the two images 11c and 12c visually recognized by the driver are reflection double images. The angle formed between the light beam 11b (primary beam) and the light beam 12b (secondary beam) is the angle α of the reflected double image. The angle α of the reflected double image is preferably closer to zero. In the present application, a reflected double image when the secondary beam is seen upward as viewed from the driver is defined as a positive value.

  Further, as shown in FIG. 1B, a part of the light beam 41a emitted from the light source 40 enters the inside from the outer surface 22 of the vehicle windshield 20 and is refracted. A part of the light is refracted from the inner surface 21 to the outside of the windshield 20, guided to the driver's eyes 30 as a light ray 41b, and visually recognized by the driver as an image 41c.

  Further, a part of the light beam 42 a emitted from the light source 40 enters the inside from the outer surface 22 of the windshield 20 of the vehicle and is refracted, and a part thereof is reflected by the inner surface 21. Further, a part of the light is reflected by the outer surface 22, and a part of the light is further refracted from the inner surface 21 to the outside of the windshield 20 and guided to the driver's eyes 30 as a light ray 42b, and visually recognized by the driver as an image 42c. Is done.

  Thus, the two images 41c and 42c visually recognized by the driver are perspective double images. The angle formed by the light ray 41b (primary beam) and the light ray 42b (secondary beam) is the angle η of the perspective double image. The angle η of the perspective double image is preferably closer to zero.

[Front glass (Laminated glass)]
FIG. 2 is a diagram illustrating a windshield for a vehicle, and is a diagram schematically showing a state in which the windshield is visually recognized from the vehicle interior to the vehicle interior. In FIG. 2, for convenience, the HUD display area is shown as a satin pattern.

  As shown in FIG. 2A, the windshield 20 has a HUD display area A used in the HUD and a HUD display outside area B (transparent area) not used in the HUD. The HUD display area A is a range in which the windshield 20 is irradiated with light from the mirror constituting the HUD when viewed from the V1 point of JIS R3212 by rotating the mirror constituting the HUD.

The HUD display area A is located below the windshield 20, and the HUD display outside area B is located adjacent to the HUD display area A and around the HUD display area A of the windshield 20. However, HUD display area, for example, as the HUD display area _{A 1} and the HUD display area _{A 2} shown in FIG. 2 (b), may be arranged separately in a plurality of locations in the Y direction. Alternatively, HUD display area may be only one of the HUD display area _{A 1} and the HUD display area _{A 2.} Alternatively, the HUD display area may be divided into a plurality of locations in the Z direction (not shown). The HUD display areas A, A ₁ and A ₂ are representative examples of areas used in the head-up display according to the present invention.

  3 is a partial cross-sectional view of the windshield 20 shown in FIG. 2 cut in the XZ direction and viewed from the Y direction. As shown in FIG. 3, the windshield 20 is a laminated glass including a glass plate 210 that is a first glass plate, a glass plate 220 that is a second glass plate, and an intermediate film 230. In the windshield 20, the glass plate 210 and the glass plate 220 are fixed with the intermediate film 230 sandwiched therebetween.

  In the windshield 20 which is a laminated glass, the glass plates 210 and 220 have a streak produced by stretching during production. The intermediate film 230 is located between the glass plate 210 and the glass plate 220, and is a film that bonds the glass plate 210 and the glass plate 220 so that the lines of the glass plate 210 and the lines of the glass plate 220 are orthogonal to each other, for example. .

  Even if the inner surface 21 of the windshield 20 that is one surface of the glass plate 210 that is the inner side of the vehicle and the outer surface 22 of the windshield 20 that is one surface of the glass plate 220 that is the outer side of the vehicle are flat surfaces. It may be a curved surface.

  The HUD display area A is formed in a wedge shape in cross-sectional view that changes in thickness from the lower end side to the upper end side of the windshield 20 when the windshield 20 is attached to the vehicle, and the wedge angle is δ. The value of the wedge angle may be different depending on the position in the vertical direction in at least a part of the region where the cross-sectional shape of the windshield 20 is wedge-shaped. That is, the wedge-shaped region of the windshield 20 may include a region having a variable wedge angle.

  Here, the wedge angle in the area from the upper end of the HUD display area A to the upper end of the windshield 20 may be smaller than the wedge angle in the HUD display area A. If the wedge angle in the area from the upper end of the HUD display area A to the upper end of the windshield 20 is smaller than the wedge angle in the HUD display area A, the wedge angle from the lower end side to the upper end side of the windshield 20 is constant. The windshield 20 can be reduced in weight, which is preferable. An in-vehicle camera may be disposed inside the windshield 20 and in the vicinity of the upper end of the windshield 20. The in-vehicle camera acquires information on the outside of the vehicle through the windshield 20, but if the windshield 20 is thick, the visible light transmittance is reduced. If the wedge angle in the area from the upper end of the HUD display area A to the upper end of the windshield 20 is smaller than the wedge angle in the HUD display area A, the wedge angle from the lower end side to the upper end side of the windshield 20 is constant. Since the thickness of the windshield 20 can be reduced, the reduction of visible light transmittance in the see-through region of the in-vehicle camera can be suppressed, which is preferable.

  The average value of the wedge angle δ in the HUD display area A is preferably 0.1 mrad or more. This is because when the average value of the wedge angle δ of the HUD display area A is 0.1 mrad or more, the effect of changing the wedge angle is sufficiently exhibited. The average value of the wedge angle δ of the HUD display area A is preferably 1.5 mrad or less, more preferably 0.7 mrad or less, more preferably 0.6 mrad or less, and 0.5 mrad or less. More preferably, it is more preferably 0.4 mrad or less. If the average value of the wedge angle δ in the HUD display area A is 1.5 mrad or less, the reflected double image can be reduced. If the average value of the wedge angle δ in the HUD display area A is 0.4 mrad or less, the FOV (Field Of View: viewing angle) in the vertical direction (Z direction) is 2 degrees or more (a larger image than the conventional image on the windshield). Even when the projection is attempted), the reflected double image can be reduced. If the average value of the wedge angle δ in the HUD display area A is 0.4 mrad or less, the reflected double image is obtained even when the distance between the HUD image and the viewer in the horizontal direction (X direction) is increased. Can be reduced. In other words, the longer the distance between the HUD image and the viewer in the horizontal direction (X direction), the smaller the wedge angle δ is preferable.

  The wedge angle δ is based on 13 pieces of data existing within a range of 30 mm before and after a certain point from the plate thickness of the windshield 20 measured every 5 mm in the vertical direction when the windshield 20 is attached to the vehicle. The average change rate of the thickness of the windshield 20 obtained by the least square method is used. The slope of the wedge angle δ is the average change rate of the wedge angle obtained by the least square method in the same range. The average value of the wedge angle δ is a further average value of the wedge angle δ defined above.

  In the windshield 20, the wedge-shaped region of the HUD display region A is formed by making any one or more of the glass plates 210 and 220 and the intermediate film 230 into a wedge shape. That is, in FIG. 3, the glass plates 210 and 220 have a constant thickness and the intermediate film 230 has a wedge shape. However, the intermediate film 230 may have a constant thickness, and one or both of the glass plate 210 and the glass plate 220 may be formed in a wedge shape. Alternatively, the intermediate film 230 may be formed in a wedge shape, and one or both of the glass plate 210 and the glass plate 220 may be formed in a wedge shape.

  In the case where one or both of the glass plate 210 and the glass plate 220 are formed in a wedge shape, conditions for manufacturing by the float process are devised. That is, by adjusting the peripheral speed of a plurality of rolls arranged at both ends in the width direction of the glass ribbon traveling on the molten metal, the glass cross section in the width direction is made into a concave shape, a convex shape, or a tapered shape. What is necessary is just to cut out the part with thickness change.

  The glass plates 210 and 220 each have fine streaks in parallel to the traveling direction due to stretching during production by the float method (streaks). When used as a windshield for a vehicle, if the streak is seen in the horizontal direction with respect to the observer's line of sight, distortion occurs and visibility deteriorates.

  As the glass plates 210 and 220, for example, soda lime glass, aluminosilicate, organic glass, or the like can be used. It is preferable that the plate | board thickness of the glass plate 220 located in the outer side of the windshield 20 is 1.8 mm or more and 3 mm or less. If the thickness of the glass plate 220 is less than 1.8 mm, the stepping stone performance is lowered, and if it is thicker than 3 mm, it becomes heavy and difficult to mold.

  It is preferable that the plate | board thickness of the glass plate 210 located inside the windshield 20 is 0.3 mm or more and 2.3 mm or less. If the thickness of the glass plate 210 is less than 0.3 mm, handling becomes difficult, and if it is greater than 2.3 mm, it becomes impossible to follow the shape of the intermediate film 230 that is a wedge film. However, the thickness of each of the glass plates 210 and 220 does not necessarily have to be constant, and the thickness may vary from place to place as necessary.

  The windshield 20 may not have a curved shape, but may have a curved shape. In the case of a curved shape, when two sheets of glass that are particularly deeply bent are formed as the glass plates 210 and 220, the difference between the two shapes (mismatch) ), Which greatly affects the glass quality (for example, residual stress) after pressure bonding.

  The glass quality (for example, residual stress) can be maintained by using a variable wedge angle and setting the thickness of the glass plate 210 to 0.3 mm or more and 2.3 mm or less. Setting the thickness of the glass plate 210 to 0.3 mm or more and 2.3 mm or less is particularly effective in maintaining the glass quality (for example, residual stress) in deeply bent glass.

  When the windshield 20 has a curved shape, the glass plates 210 and 220 are bent after being formed by the float process and before being bonded by the intermediate film 230. Bending is performed by softening the glass by heating. The heating temperature of the glass at the time of bending is approximately 550 ° C to 700 ° C.

  4 is a cross-sectional view of the windshield 20 shown in FIG. 2 viewed in the Y direction by cutting in the XZ direction. As shown in FIG. 4, when the windshield 20 has a curved shape, the deepest portion of the concave surface 20 </ b> D from a straight line La connecting the midpoints of the longer opposite sides of the two opposite sides of the concave surface 20 </ b> D of the windshield 20. The distance in the direction perpendicular to the straight line La is the maximum bending depth D of the windshield 20.

  If the maximum bending depth D of the windshield 20 is 10 mm or more, the lines can be sufficiently stretched by bending and visibility can be sufficiently improved. The maximum bending depth D is preferably 12 mm or more, more preferably 15 mm or more. The bending radius of the concave surface 20D is preferably larger than 6000 mm. Since the bending radius of the concave surface 20D is larger than 6000 mm, the HUD image is hardly distorted. The bending radius of the concave surface 20D is more preferably 7000 mm or more, and further preferably 8000 mm or more.

  Each color of the glass plates 210 and 220 is not particularly limited as long as the visible light transmittance (Tv)> 70%.

  Further, it is preferable that a so-called “black sera” shielding layer is present in the periphery of the windshield 20. This shielding layer is formed by applying black Sera printing ink on a glass surface and baking it. By this shielding layer, a black opaque layer is formed in the periphery of the windshield 20, and the black opaque layer suppresses deterioration of the resin such as urethane holding the windshield 20 in the vicinity thereof by ultraviolet rays. .

  In addition, a coating having a water repellent function, an infrared shielding function, an ultraviolet shielding function, and a visible light reflectance reducing function on the outer side (outer surface of the glass plate 220) and the inner side (inner surface of the glass plate 210) of the windshield 20 and low radiation characteristics. You may have the film which has.

  Returning to the description of FIG. 3, a thermoplastic resin is often used as the intermediate film 230 for bonding the glass plate 210 and the glass plate 220. For example, a plasticized polyvinyl acetal resin, a plasticized polyvinyl chloride resin, a saturated polyester is used. Conventionally used for this kind of applications such as resin, plasticized saturated polyester resin, polyurethane resin, plasticized polyurethane resin, ethylene-vinyl acetate copolymer resin, ethylene-ethyl acrylate copolymer resin, etc. A thermoplastic resin is mentioned.

  Among these, plastics having excellent balance of various properties such as transparency, weather resistance, strength, adhesion, penetration resistance, impact energy absorption, moisture resistance, heat insulation, and sound insulation can be obtained. A polyvinyl acetal resin is preferably used. These thermoplastic resins may be used alone or in combination of two or more. “Plasticization” in the plasticized polyvinyl acetal resin means that it is plasticized by adding a plasticizer. The same applies to other plasticized resins.

  The polyvinyl acetal-based resin is a polyvinyl formal resin obtained by reacting polyvinyl alcohol (hereinafter sometimes referred to as “PVA” if necessary) and formaldehyde, and a narrow meaning obtained by reacting PVA and acetaldehyde. Polyvinyl acetal resin, polyvinyl butyral resin obtained by reacting PVA and n-butyraldehyde (hereinafter sometimes referred to as “PVB” if necessary), and the like, in particular, transparency and weather resistance. PVB is preferred because of its excellent balance of various properties such as strength, adhesive strength, penetration resistance, impact energy absorption, moisture resistance, heat insulation, and sound insulation. These polyvinyl acetal resins may be used alone or in combination of two or more. However, the material for forming the intermediate film 230 is not limited to the thermoplastic resin.

  The thickness of the intermediate film 230 is preferably 0.5 mm or more at the thinnest portion. When the thickness of the intermediate film 230 is less than 0.5 mm, the penetration resistance required for the windshield cannot be secured. The thickness of the intermediate film 230 is preferably 3 mm or less at the thickest portion. If the thickness of the intermediate film 230 is thicker than 3 mm, the weight becomes heavy and the handleability deteriorates.

  The intermediate film 230 may include a region having a sound insulation function, an infrared shielding function, an ultraviolet shielding function, a shade band (a function for reducing visible light transmittance), and the like. Further, the intermediate film 230 may have three or more layers. For example, if the intermediate film 230 is composed of three layers and the hardness of the middle layer is lower than the hardness of the layers on both sides, the sound insulation can be improved. In this case, the hardness of the layers on both sides may be the same or different.

  Thus, when the number of layers of the intermediate film 230 increases, the thickness of each layer changes, and the optical quality of, for example, the above-described perspective double image may be further deteriorated. In this case, by setting the plate thickness of the glass plate 210 to 0.3 mm or more and 2.3 mm or less, it becomes easy to follow the wedge film of the intermediate film 230, so that deterioration of optical quality can be suppressed. That is, setting the thickness of the glass plate 210 to 0.3 mm or more and 2.3 mm or less is particularly effective when the number of layers of the intermediate film 230 is increased.

  Usually, the light source of the HUD is located in the lower part of the passenger compartment, and is projected onto the laminated glass from there. Since the projected images are reflected by the back and front surfaces of the glass plates 210 and 220, the thickness of the glass must be changed in parallel to the projection direction in order to superimpose both reflected images so as not to generate a double image. is necessary. When the thickness of the glass plate 210 changes in a direction perpendicular to the streak, the streak direction is perpendicular to the projection direction, that is, the streak is a vehicle interior observer (driver). ) Line of sight and the horizontal direction, it must be used in such a direction that visibility deteriorates.

  In order to improve the visibility, the laminated glass produced using the glass plate 210, the glass plate 220, and the intermediate film 230 is arranged so that the lines of the glass plate 210 and the lines of the glass plate 220 are orthogonal to each other. With this arrangement, the distortion that is deteriorated by the glass plate 210 alone is alleviated by the presence of the glass plate 220 having straight lines and the intermediate film 230 that bonds the glass plate 210 and the glass plate 220, and visibility is improved.

  In addition, when the glass plates 210 and 220 are not wedge glasses, both the glass plates 210 and 220 are in a direction perpendicular to the line of sight of the vehicle interior observer (driver), and visibility is not deteriorated.

  In order to produce the intermediate film 230, for example, the above-described resin material to be the intermediate film 230 is appropriately selected, and extrusion molding is performed in a heated and melted state using an extruder. The extrusion conditions such as the extrusion speed of the extruder are set to be uniform. Thereafter, the extruded resin film is extended so as to give curvature to the upper side and the lower side in accordance with the design of the windshield 20, thereby completing the intermediate film 230.

  In order to produce a laminated glass, a laminated body is formed by sandwiching the stretched intermediate film 230 between the glass plate 210 and the glass plate 220. For example, this laminated body is put in a rubber bag, and is −65 to −100 kPa. In a vacuum of about 70-110 ° C.

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

  In addition, between the glass plate 210 and the glass plate 220, in addition to the intermediate film 230, a film having functions such as heating wire, infrared reflection, light emission, power generation, dimming, visible light reflection, scattering, decoration, and absorption Or you may have a device.

  FIG. 5 is a diagram for explaining the visible light transmittance of a laminated glass (front glass). FIG. 5A shows a case where the intermediate film 230 has a wedge shape, and FIG. 5B shows a case where the glass plate 210 has a wedge shape. Here, as an example, a case where the intermediate film 230 is made of PVB (infrared shielding function is small) and the glass plate 210 is made of green glass will be described.

  Comparing green glass with PVB having a small infrared shielding function, green glass has a lower visible light transmittance per unit thickness. Therefore, when the windshield 20 has the same shape (the same thickness at each position in the vertical direction) in FIGS. 5A and 5B, the visible light transmittance of the entire laminated glass is as shown in FIG. ) Is lower. As a result, the reflected double image becomes darker in the case of FIG. The reason for this will be described with reference to FIG.

  FIG. 6 is a diagram illustrating luminance images of the main image and the reflected double image, and schematically shows a case where the positions of the main image and the reflected double image are shifted due to the wedge angle error in the laminated glass. . 6A shows the case of the windshield of FIG. 5A, and FIG. 6B shows the case of the windshield of FIG. 5B. In FIG. 6, 21c schematically shows a main image, and 22c schematically shows a reflected double image.

  Comparing FIG. 6 (a) and FIG. 6 (b), in FIG. 6 (b), compared to FIG. 6 (a), the luminance of the main image 21c + the luminance of the reflected double image 22c, and the reflected double All the luminances of only the image 22c decrease at the same rate.

  Since the main image + reflected double image is originally bright and the rate of decrease in luminance is low, even if FIG. 6 (b) is compared with FIG. 6 (a), the viewer can see the main image 21c in FIG. 6 (b). It is difficult to feel that the brightness + the brightness of the reflected double image 22c is lower (darker) than the brightness of the main image 21c + the brightness of the reflected double image 22c in FIG.

  On the other hand, since the brightness of the reflected double image 22c is high, the value of the brightness of the reflected double image 22c / (the brightness of the main image 21c + the brightness of the reflected double image 22c) is as shown in FIG. This is much smaller than in FIG. Therefore, when FIG. 6B is compared with FIG. 6A, the viewer can easily feel that the reflected double image 22c in FIG. 6B is darker than the reflected double image 22c in FIG. . That is, in FIG. 6B, the reflected double image becomes less conspicuous than in FIG.

  Thus, in the laminated glass having a wedge angle, when the error of the wedge angle occurs, the positions of the main image 21c and the reflected double image 22c are shifted, so that the reflected double image 22c is visually recognized, but the entire laminated glass By reducing the visible light transmittance, it is possible to make the reflected double image inconspicuous.

  FIG. 7 is an example of a result of measuring the relationship between the total thickness of the laminated glass and the visible light transmittance of the laminated glass. When the thickness of the glass plate 210 made of green glass is changed (circle), from PVB The case where the thickness of the intermediate film 230 is changed (square) is shown. However, here, the thickness of the laminated glass is constant and does not have a wedge-shaped region.

  Further, in FIG. 7, the case where the thickness of the glass plate 210 is 2.3 mm, the thickness of the intermediate film 230 is 0.86 mm, and the thickness of the glass plate 220 is 2.3 mm is defined as a reference (Ref). Thus, the visible light transmittance of the laminated glass when the thickness of the glass plate 210 or the thickness of the intermediate film 230 is changed is measured and compared.

  As shown in FIG. 7, when the thickness of the glass plate 210 is increased, the visible light transmittance of the laminated glass decreases more than when the thickness of the intermediate film 230 is increased. From this, it can be seen that the effect of darkening the reflection double image (making it inconspicuous) is greater when the thickness of the glass plate 210 is increased.

  FIG. 8 shows the change in the visible light transmittance of the laminated glass when either the glass plate 220 or the intermediate film 230 is wedge-shaped. That is, the vertical axis in FIG. 8 is the visible light transmittance (%) of the laminated glass.

  FIG. 8A shows the case of an intermediate film 230 made of PVB (small infrared shielding function) and glass plates 210 and 220 made of green glass. That is, in this case, the glass plates 210 and 220 have a lower visible light transmittance per unit thickness than the intermediate film 230.

  FIG. 8B shows a case where the visible light transmittance per unit thickness of the intermediate film 230 is lower than that of FIG. 8A by strengthening the infrared shielding function of PVB in FIG. 8A. In this case, however, the glass plates 210 and 220 have a lower visible light transmittance per unit thickness than the intermediate film 230, as in FIG. In general, when an infrared shielding function is added, not only the infrared transmittance is lowered, but also the visible light transmittance is lowered.

  FIG. 8C shows a case where the visible light transmittance per unit thickness of the intermediate film 230 is further lowered than that in FIG. 8B by further strengthening the infrared ray shielding function of PVB than in FIG. 8B. Yes. 8C, unlike in FIGS. 8A and 8B, the visible light transmittance per unit thickness of the intermediate film 230 is lower than the visible light transmittance per unit thickness of the glass plates 210 and 220. .

  Further, in each of A, B, and C in FIG. 8, the left side shows the case where the thickness of each of the glass plates 210 and 220 and the intermediate film 230 is constant (when they are not wedge-shaped) for reference. The center shows data of the thickest portion of the HUD display area when only the intermediate film 230 is wedge-shaped. Further, the right side shows data of a portion where the total thickness of the HUD display area is the thickest when only the glass plate 220 is wedge-shaped.

  As shown in FIGS. 8A and 8B, when the visible light transmittance per unit thickness of the glass plates 210 and 220 is lower than the visible light transmittance per unit thickness of the intermediate film 230, the intermediate film 230 is wedge-shaped. Rather than (center), the glass plate 210 or 220 having a wedge shape (right side) can further reduce the visible light transmittance of the laminated glass.

  On the other hand, when the visible light transmittance per unit thickness of the intermediate film 230 is lower than the visible light transmittance per unit thickness of the glass plates 210 and 220 as shown in FIG. Rather than making 210 or 220 wedge-shaped (right side), the intermediate film 230 can be wedge-shaped (center), and the visible light transmittance of the laminated glass can be further reduced.

  That is, among the constituent members of the laminated glass (glass plates 210 and 220, intermediate film 230), the member having a lower visible light transmittance per unit thickness is wedge-shaped so that the visible light transmittance of the entire laminated glass is increased. It can be greatly reduced. As a result, it is possible to increase the effect of making the reflected double image dark (not noticeable).

  In the above example, the visible light transmittance per unit thickness of the intermediate film 230 is reduced by providing the infrared shielding function. However, the visible light transmission per unit thickness of the intermediate film 230 is reduced by other methods. The rate may be reduced.

  As described above, the thickness of the intermediate film 230 is preferably 0.5 mm or more at the thinnest part. However, when the intermediate film 230 is wedge-shaped, the thickness of the thinnest part of the intermediate film 230 in the HUD display region is set. Is preferably 0.65 mm or more. It is more preferably 0.7 mm or more, more preferably 0.75 mm or more, more preferably 0.8 mm or more, more preferably 0.9 mm or more, and further preferably 1.0 mm or more. By setting the thickness of the thinnest part of the intermediate film 230 in the HUD display area to be 0.65 mm or more, the visible light transmittance can be sufficiently reduced. By setting the thickness of the thinnest part of the intermediate film 230 in the HUD display area to 0.8 mm or more, the visible light transmittance can be sufficiently reduced, and at the same time, thermal energy (solar radiation) flowing from the outside through the HUD display area. Therefore, it is possible to prevent the HUD light source 10 in the vehicle interior from being heated by heat energy from the outside.

  When the laminated glass is wedge-shaped, the laminated glass is visible at the thickest part (upper end of the vertical area of the HUD display area) and the thinnest part (lower end of the vertical area of the HUD display area) in the HUD display area. The light transmittance is different. Therefore, the difference Δt in the thickness between the thickest and thinnest portions of the laminated glass in the HUD display region, and the difference in the visible light transmittance between the thickest and thinnest portions of the laminated glass in the HUD display region. Regarding the relationship with ΔTv, the case where the intermediate film 230 is made of PVB and the glass plate 210 is made of green glass was examined.

  FIG. 9 is a diagram illustrating the relationship between the thickness difference Δt and the visible light transmittance difference ΔTv. When the intermediate film 230 made of PVB (having an infrared shielding function) is wedge-shaped and green glass The case where the glass plate 210 which consists of this is made into a wedge shape is compared. Table 1 is a numerical value based on FIG.

As shown in Table 1 and FIG. 9, the thickness difference Δt and the visible light transmittance difference ΔTv are proportional to each other regardless of whether the intermediate film 230 is wedge-shaped or the glass plate 210 is wedge-shaped. Then, the inclination when the glass plate 210 is wedged is steeper than when the intermediate film 230 is wedged.

  Further, the inclined line shown in FIG. 9 is a line of ΔTv = 2.2Δt. This inclination line is obtained by experimentally obtaining a level at which the effect of darkening the reflection double image (making it inconspicuous) can be confirmed by checking with 10 people while changing Δt. That is, if ΔTv ≧ 2.2Δt, the visible light transmittance of the entire laminated glass is lowered, and thus the effect of making the reflected double image dark (not noticeable) can be sufficiently obtained.

  Here, the case where the glass plates 210 and 220 have a lower visible light transmittance per unit thickness than the intermediate film 230 was examined. However, the glass plates 210 and 220 are more unit than the intermediate film 230. Even when the visible light transmittance per thickness is high, the same result as in FIG. 9 is obtained. However, in this case, the case where the intermediate film 230 has a wedge shape is located above the inclined line in FIG.

  That is, in order to satisfy ΔTv ≧ 2.2Δt, among the laminated glass constituent members (glass plates 210 and 220, intermediate film 230), the member having the lower visible light transmittance per unit thickness is wedge-shaped. It can be said that adjusting the thickness is effective.

  On the other hand, despite the decrease in the visible light transmittance of the laminated glass, the subject did not feel a decrease in the brightness of the entire HUD image, so the equation ΔTv ≧ 2.2Δt is the main image + reflection double It can be said that the visibility of the reflected double image can be lowered while suppressing the decrease in the luminance of the image to a level where it cannot be visually recognized.

  In this way, even if the intermediate film or the glass plate is in a wedge shape, the visible light transmittance of the entire laminated glass can be greatly reduced by satisfying the relationship of ΔTv ≧ 2.2Δt, As a result, it is possible to sufficiently obtain the effect of making the reflected double image dark (not noticeable).

  In order to obtain a greater effect, ΔTv ≧ 2.4Δt is preferable, and ΔTv ≧ 2.6Δt is more preferable. By satisfying ΔTv ≧ 2.4Δt, it is possible to further reduce the luminance of the reflected double image and suppress the decrease in the luminance of the main image + the reflected double image to a level that cannot be visually recognized by the observer. Further, by satisfying ΔTv ≧ 2.6Δt, it is possible to further reduce the luminance of the reflected double image and suppress the decrease in the luminance of the main image + the reflected double image to a level that cannot be visually recognized by the observer.

  The preferred embodiments and the like have been described in detail above, but the present invention is not limited to the above-described embodiments and the like, and various modifications can be made to the above-described embodiments and the like without departing from the scope described in the claims. Variations and substitutions can be added.

10, 40 Light source 11a, 11b, 12a, 12b, 41a, 41b, 42a, 42b Ray 11c, 12c, 41c, 42c Image 20 Windshield 21c Main image 22c Reflective double image 20D Concave surface 21 Inner surface 22 Outer surface 30 Eye 210, 220 Glass plate 230 Intermediate film A, A ₁ , A ₂ HUD display area B HUD display outside area δ Wedge angle

Claims (11)

A first glass plate located on the inside of the vehicle; a second glass plate located on the outside of the vehicle; and the first glass located between the first glass plate and the second glass plate. A laminated glass comprising an intermediate film for bonding the plate and the second glass plate,
It has a display area for use with a head-up display,
The display area includes a wedge-shaped area in which the thickness of the upper end side in the vertical direction when the laminated glass is attached to the vehicle is thicker than the lower end side,
The difference in thickness Δt [mm] between the thickest part and the thinnest part of the display area and the difference ΔTv [%] in the visible light transmittance between the thickest part and the thinnest part of the display area are ΔTv ≧ A laminated glass characterized by satisfying the relationship of 2.2 Δt.   The laminated glass of Claim 1 satisfy | filling the relationship of (DELTA) Tv> = 2.4 (DELTA) t.   The laminated glass of Claim 2 which satisfy | fills the relationship of (DELTA) Tv> = 2.6 (DELTA) t.   4. The member having a lower visible light transmittance per unit thickness among the first glass plate, the second glass plate, and the intermediate film is wedge-shaped. 5. Laminated glass.   The laminated glass according to claim 4, wherein one or both of the first glass plate and the second glass plate are wedge-shaped. The intermediate film is wedge-shaped;
The laminated glass of Claim 4 whose thickness of the thinnest part of the said intermediate film in the said display area is 0.65 mm or more.   The laminated glass according to any one of claims 1 to 6, wherein the intermediate film includes a polyvinyl butyral resin, and the first glass plate and the second glass plate are green glass.   The laminated glass as described in any one of Claims 1 thru | or 7 whose average value of the wedge angle in the said wedge-shaped area | region is 1.5 mrad or less.   The laminated glass according to any one of claims 1 to 8, wherein an average value of a wedge angle in the wedge-shaped region is 0.4 mrad or less.   The laminated glass according to any one of claims 1 to 9, wherein a bending radius in the vertical direction is 6000 mm or more.   The laminated glass according to any one of claims 1 to 10, wherein a wedge angle in a region from an upper end of the display region to an upper end of the laminated glass is smaller than a wedge angle in the wedge-shaped region.