Windshield

Abstract

To provide a windshield that suppresses a double image of a display area by an HUD device for changing the display area in a vertical direction, and is easily manufactured.SOLUTION: A windshield is provided with an HUD device capable of changing a plurality of display areas in a vertical direction. In a glass plate of the display area, a thickness of an upper end part is thicker than that of a lower end part, and a first principal surface and a second principal surface make a wedge angle α. When a height of the entire display area in the vertical direction is Y, a range of the wedge angle α in a first region between a line 0.15Y upwardly away from a line passing a center in the vertical direction of both sides in the entire display area, and a line 0.15Y downwardly away is S_Center, a range of the wedge angle α in a second region between an upper side of the entire display area and a line 0.3Y downwardly away from the upper side is S_Upper, and a range of the wedge angle α in a third region between a lower side of the entire display area and a line 0.3Y upwardly away from the lower side is S_Lower, relations of S_Center<S_Upper, and S_Center<S_Lower are satisfied.SELECTED DRAWING: Figure 14

Description

[Technical field]

[0001] The present invention relates to a windshield. [Background technology]

[0002] A windshield in which a head-up display (HUD) device is used is formed in a wedge shape to prevent double images. Patent Document 1 also proposes a windshield in which a plurality of lattice points are defined within the display area of ​​the HUD device projected onto the windshield, and when the wedge angle at each lattice point is measured, the difference between the maximum and minimum values ​​of the wedge angle is within 0.32 mrad. This makes it possible to prevent double images from occurring even if the display area is enlarged. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6770470 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, a HUD device capable of switching the display area in the vertical direction according to the driver's line of sight has been proposed. The inventor has studied this and found that the optimal wedge angle for suppressing double images changes as the display area moves in the vertical direction. Therefore, in order to suppress double images in each display area, it is necessary to set the wedge angle of the windshield so as to correspond to the change in the optimal wedge angle, but such a windshield is considered difficult to manufacture and has not yet been proposed. The present invention has been made to solve the above problem, and aims to provide a windshield that is easy to manufacture while suppressing double images in all display areas when using a HUD device that can switch the display area in the vertical direction. [Means for solving the problem]

[0005] Item 1. A windshield provided with a HUD device capable of switching a plurality of display areas in the vertical direction, comprising a glass plate having a first main surface and a second main surface opposite thereto, and the display area being formed thereon, the glass plate is configured such that the thickness of the upper end portion is formed thicker than that of the lower end portion, so that the first main surface and the second main surface form a wedge angle α, let the vertical height of the entire display area including all of the plurality of display areas be Y, let the range of the wedge angle α in the first area between the line 0.15Y away from the line passing through the vertical centers of both sides of the entire display area upward and the line 0.15Y away from the line downward be S_Center, let the range of the wedge angle α in the second area between the upper side of the entire display area and the line 0.3Y away from the upper side downward be S_Upper, let the range of the wedge angle α in the third area between the lower side of the entire display area and the line 0.3Y away from the lower side upward be S_Lower, then a windshield that satisfies S_Center < S_Upper and S_Center < S_Lower.

[0006] Item 2. The windshield according to Item 1, wherein the plurality of display areas are configured to overlap in the vertical direction.

[0007] Item 3. The windshield according to Item 1 or 2, which is curved so as to be convex outward in the horizontal direction.

[0008] Item 4. Having a plurality of regions with different radii of curvature in the horizontal direction, the windshield according to Item 3, wherein the display area is provided in the region having a larger radius of curvature in the horizontal direction.

[0009] Item 5. The windshield according to any one of Items 1 to 4, which is curved so as to be convex outward in the vertical direction.

[0010] Item 6. Having a plurality of regions with different radii of curvature in the vertical direction, Item 6. The windshield according to item 5, wherein the display area is provided in the area having the large radius of curvature in the vertical direction. Effect of the Invention

[0011] According to the present invention, even when a HUD device capable of switching the display area in the vertical direction is used, it is possible to suppress double images in all display areas. [Brief description of the drawings]

[0012] [Figure 1] 1 is a plan view showing one embodiment of a windshield according to the present invention. FIG. [Diagram 2] 2 is a cross-sectional view taken along line AA in FIG. 1. [Diagram 3] FIG. 2 is a cross-sectional view showing an example of a method for producing an interlayer film. [Figure 4] FIG. 4 is a plan view of FIG. [Diagram 5] FIG. 2 is a plan view of a mold used to manufacture the windshield. [Figure 6] 1 is a schematic diagram showing a manufacturing process of a windshield. [Figure 7] FIG. 2 is a cross-sectional view showing the HUD device and the windshield. [Figure 8] FIG. 2 is a cross-sectional view showing the HUD device and the windshield. [Figure 9] FIG. 2 is a front view showing three display areas of the HUD device. [Figure 10] FIG. 13 is a diagram showing a grating used for measuring a double image. [Figure 11] 11 is a graph showing an allowable wedge angle for suppressing double images measured in the upper region. [Figure 12] 1 is a graph showing an acceptable wedge angle for suppressing double images measured in a central region. [Figure 13] 13 is a graph showing an acceptable wedge angle for suppressing double images measured in the lower region. [Figure 14] 1 is a graph showing the allowable wedge angles of three display regions. [Figure 15] FIG. 2 is a front view showing three display areas. [Figure 16] FIG. 2 is a front view showing three display areas. [Figure 17] FIG. 4 is a front view showing the position of a display area on the windshield. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] <1. Windshield Overview> Hereinafter, an embodiment of a windshield for an automobile according to the present invention will be described with reference to the drawings. The windshield according to the present embodiment is used to display information by projecting light emitted by a HUD (head-up display) device.

[0014] FIG. 1 is a front view of the windshield according to this embodiment, and FIG. 2 is a cross-sectional view taken along line AA in FIG. 1. As shown in FIGS. 1 and 2, the windshield according to this embodiment includes an outer glass sheet 1 facing the outside of the vehicle, an inner glass sheet 2 facing the inside of the vehicle, and an interlayer film 3 disposed between these glass sheets 1 and 2 when installed in an automobile, and has an overall wedge-shaped cross section (wedge angle α). A shielding layer 4 is laminated on this windshield. Note that in each drawing of this embodiment, the wedge angle is shown to be exaggerated from the actual angle for ease of explanation. Each member will be described below.

[0015] <2. Outer glass plate and inner glass plate> First, the outer glass plate 1 and the inner glass plate 2 will be described. The outer glass plate 1 and the inner glass plate 2 can be made of known glass plates, and can also be made of heat absorbing glass, general clear glass, green glass, or UV green glass. However, these glass plates 1 and 2 must achieve a visible light transmittance that meets the safety standards of the country in which the automobile is used. For example, the outer glass plate 1 can ensure the required solar radiation absorptance, and the inner glass plate 2 can adjust the visible light transmittance to meet the safety standards. Examples of clear glass, heat absorbing glass, and soda lime glass are shown below.

[0016] (Clear glass) SiO 2 :70~73% by mass Al 2 O 3 :0.6~2.4% by mass CaO: 7~12% by mass MgO: 1.0~4.5% by mass R 2 O: 13 to 15 mass% (R is an alkali metal) Fe 2 O 3 Total iron oxide (T-Fe 2 O 3 ):0.08~0.14% by mass

[0017] (Heat absorbing glass) The composition of heat absorbing glass is, for example, based on the composition of clear glass, Fe 2 O 3 Total iron oxide (T-Fe 2 O 3 ) is 0.4 to 1.3 mass%, and CeO 2 The ratio of TiO is 0 to 2 mass%. 2 The ratio of is 0 to 0.5 mass%, and the glass framework component (mainly SiO 2 Or Al 2 O 3 ) to T-Fe 2 O 3 , CEO 2 and TiO 2 The composition can be reduced by the increase in

[0018] (Soda-lime glass) SiO 2 :65~80% by mass Al 2 O 3 :0~5% by mass CaO: 5~15% by mass MgO: 2% by mass or more NaO: 10~18% by mass K 2 O: 0~5% by mass MgO+CaO: 5~15% by mass Na 2 O+K 2 O: 10~20% by mass SO 3 :0.05~0.3 mass% B 2 O 3 :0~5% by mass Fe 2 O 3 Total iron oxide (T-Fe 2 O 3 ):0.02~0.03% by mass

[0019] The outer glass plate 1 is formed in a trapezoidal shape and has an upper side (short side) 11, a lower side (long side) 12 that is longer than the upper side 11, a right side 13, and a left side 14. When installed in a vehicle, the upper side 11 is positioned on the upper side, and the right side 13 and left side 14 are positioned on the right and left sides, respectively, when viewed from inside the vehicle.

[0020] Similarly, the inner glass plate 2 is formed in a trapezoidal shape, and has an upper side 21, a lower side 22, a right side 23, and a left side 24. The inner glass plate 2 also has a first surface 201 facing the outside of the vehicle and a second surface 202 facing the inside of the vehicle, and has an end surface connecting the first surface 201 and the second surface 202. That is, in this embodiment, both the outer glass plate 1 and the inner glass plate 2 are formed in a flat plate shape.

[0021] The above-mentioned interlayer film 3 is disposed between the second surface 102 of the outer glass plate 1 and the first surface 201 of the inner glass plate 2 .

[0022] The thickness of the windshield according to this embodiment is not particularly limited, but from the viewpoint of weight reduction, the total thickness of the outer glass plate 1 and the inner glass plate 2 is preferably 2.4 to 5.0 mm, more preferably 2.6 to 4.6 mm, and particularly preferably 2.7 to 3.2 mm. In this way, in order to reduce the weight, it is necessary to reduce the total thickness of the outer glass plate 1 and the inner glass plate 2, so that the thicknesses of the glass plates 1 and 2 are not particularly limited, but the thicknesses of the outer glass plate 1 and the inner glass plate 2 can be determined, for example, as follows.

[0023] The outer glass plate 1 is primarily required to have durability and impact resistance against external obstacles, and is required to have impact resistance against flying objects such as pebbles. On the other hand, the thicker the plate, the heavier it becomes, which is undesirable. From this viewpoint, the thickness of the outer glass plate 1 is preferably 1.8 to 2.3 mm, and more preferably 1.9 to 2.1 mm. The thickness to be adopted can be determined according to the application of the glass.

[0024] The thickness of the inner glass plate 2 can be the same as that of the outer glass plate 1, but can be made smaller than that of the outer glass plate 1, for example, to reduce the weight of the windshield. Specifically, in consideration of the strength of the glass, the thickness is preferably 0.1 to 2.3 mm, more preferably 0.8 to 2.0 mm, and particularly preferably 1.0 to 1.4 mm. Furthermore, the thickness of the inner glass plate 2 is preferably 0.8 to 1.3 mm. The thickness to be adopted for the inner glass plate 2 can also be determined depending on the application of the glass.

[0025] Moreover, the outer glass sheet 1 and the inner glass sheet 2 according to this embodiment have a curved shape. That is, they are curved so as to protrude horizontally to the outside of the vehicle. Moreover, in this curvature, the radius of curvature in the horizontal direction is not constant, and there are multiple regions with different radii of curvature. For example, the radius of curvature at both ends of the windshield can be small, and the radius of curvature in the center can be large.

[0026] Similarly, the windshield is curved in the vertical direction so as to protrude outward from the vehicle. Furthermore, the radius of curvature in the vertical direction is not constant, but rather there are multiple regions with different radii of curvature. For example, the radius of curvature of the upper part of the windshield can be smaller and the radius of curvature of the lower part can be larger.

[0027] Here, an example of a method for measuring the thickness of a windshield will be described. First, the measurement positions are two points, one above the other, on a center line that extends vertically through the center of the windshield in the left-right direction. The measuring device is not particularly limited, but for example, a thickness gauge such as SM-112 manufactured by Techlock Corporation can be used. During measurement, the curved surface of the windshield is placed on a flat surface, and the end of the windshield is clamped with the thickness gauge to perform the measurement.

[0028] <3. Interlayer film> The interlayer film 3 is formed in a trapezoidal shape, similar to both glass plates 1 and 2. As shown in FIG. 2, the interlayer film 3 has a first surface 301 facing the vehicle exterior and a second surface 302 facing the vehicle interior, and has end surfaces connecting the first surface 301 and the second surface 302. Here, the end surface on the upper side is referred to as an upper end surface 311, and the end surface on the lower side is referred to as a lower end surface 312. The interlayer film 3 is formed in a wedge shape such that the thickness decreases from the upper end surface 311 to the lower end surface 312. The wedge angle α between the first surface 301 and the second surface 302 is not particularly limited, but may be, for example, 0.02 to 0.18 mrad, or further 0.05 to 0.15 mrad.

[0029] Also, the interlayer film 3 is formed of at least one layer. As an example, as shown in the enlarged view of FIG. 2, it can be formed of three layers, in which a soft core layer 31 is sandwiched between outer layers 32 that are harder than the soft core layer 31. However, it is not limited to this configuration, and it may be formed of multiple layers including the core layer 31 and at least one outer layer 32 arranged on the outer glass sheet 1 side. For example, it can be a two-layer interlayer film 3 including the core layer 31 and one outer layer 32 arranged on the outer glass sheet 1 side, or an interlayer film 3 in which an even number of outer layers 32 of two or more are arranged on both sides of the core layer 31, or an interlayer film 3 in which an odd number of outer layers 32 are arranged on one side of the core layer 31 and an even number of outer layers 32 are arranged on the other side. When only one outer layer 32 is provided, it is provided on the outer glass sheet 1 side as described above, but this is for improving the breakage resistance performance against external forces from outside the vehicle or outdoors. Also, the more the number of outer layers 32, the higher the sound insulation performance.

[0030] The hardness of the core layer 31 is not particularly limited as long as it is softer than the outer layer 32. The materials constituting each layer 31, 32 are not particularly limited, but for example, the outer layer 32 can be made of, for example, polyvinyl butyral resin (PVB). Polyvinyl butyral resin is preferable because it has excellent adhesion to each glass plate and penetration resistance. On the other hand, the core layer 31 can be made of, for example, ethylene vinyl acetate resin (EVA) or polyvinyl acetal resin which is softer than the polyvinyl butyral resin constituting the outer layer. By sandwiching a soft core layer, it is possible to greatly improve the sound insulation performance while maintaining the same adhesion and penetration resistance as a single-layer resin interlayer.

[0031] In general, the hardness of polyvinyl acetal resin can be controlled by (a) the degree of polymerization of polyvinyl alcohol as a starting material, (b) the degree of acetalization, (c) the type of plasticizer, (d) the ratio of the plasticizer added, etc. Therefore, by appropriately adjusting at least one of these conditions, it is possible to produce a hard polyvinyl butyral resin for the outer layer 32 and a soft polyvinyl butyral resin for the core layer 31, even if the same polyvinyl butyral resin is used. Furthermore, the hardness of the polyvinyl acetal resin can be controlled by the type of aldehyde used for acetalization, whether co-acetalization with multiple types of aldehydes or pure acetalization with a single type of aldehyde. Although it cannot be said in general, the polyvinyl acetal resin obtained by using an aldehyde with a larger number of carbon atoms tends to be softer. Therefore, for example, when the outer layer 32 is made of polyvinyl butyral resin, a polyvinyl acetal resin obtained by acetalizing an aldehyde having 5 or more carbon atoms (e.g., n-hexylaldehyde, 2-ethylbutyraldehyde, n-heptylaldehyde, n-octylaldehyde) with polyvinyl alcohol can be used for the core layer 31. However, as long as a predetermined Young's modulus can be obtained, the resin is not limited to the above resins.

[0032] The total thickness of the intermediate film 3 is not particularly limited, but is preferably 0.3 to 6.0 mm, more preferably 0.5 to 4.0 mm, and particularly preferably 0.6 to 2.0 mm. The thickness of the core layer 31 is preferably 0.1 to 2.0 mm, and more preferably 0.1 to 0.6 mm. On the other hand, the thickness of each outer layer 32 is preferably 0.1 to 2.0 mm, and more preferably 0.1 to 1.0 mm. Alternatively, the total thickness of the intermediate film 3 may be constant, and the thickness of the core layer 31 may be adjusted within this. The above thicknesses are the thicknesses of the thickest portions of the intermediate film 3 formed in a wedge shape.

[0033] The thicknesses of the core layer 31 and the outer layer 32 can be measured, for example, as follows. First, a cross section of the windshield is magnified 175 times and displayed using a microscope (for example, Keyence VH-5500). Then, the thicknesses of the core layer 31 and the outer layer 32 are identified and measured by visual inspection. At this time, in order to eliminate variations due to visual inspection, the measurements are made five times, and the average values ​​are taken as the thicknesses of the core layer 31 and the outer layer 32.

[0034] The total thickness of the intermediate film 3 is not particularly limited, but is preferably 0.3 to 6.0 mm, more preferably 0.5 to 4.0 mm, and particularly preferably 0.6 to 2.0 mm. The thickness of the core layer 31 is preferably 0.1 to 2.0 mm, and more preferably 0.1 to 0.6 mm. On the other hand, the thickness of each outer layer 32 is preferably larger than the thickness of the core layer 31, and specifically, is preferably 0.1 to 2.0 mm, and more preferably 0.1 to 1.0 mm. Alternatively, the total thickness of the intermediate film 3 may be constant, and the thickness of the core layer 31 may be adjusted within this range.

[0035] The thicknesses of the core layer 31 and the outer layer 32 can be measured, for example, as follows. First, a cross section of the windshield is enlarged 175 times and displayed using a microscope (for example, Keyence VH-5500). Then, the thicknesses of the core layer 31 and the outer layer 32 are identified and measured by visual inspection. At this time, in order to eliminate variations due to visual inspection, the measurement is performed five times, and the average values ​​are taken as the thicknesses of the core layer 31 and the outer layer 32. For example, an enlarged photograph of the windshield is taken, and the core layer and the outer layer 32 are identified in the photograph and their thicknesses are measured.

[0036] The method for producing the intermediate film 3 is not particularly limited, but examples thereof include a method in which a resin component such as the above-mentioned polyvinyl acetal resin, a plasticizer, and other additives as necessary are blended and kneaded uniformly, and then each layer is extruded at once, and a method in which two or more resin films produced by this method are laminated by a pressing method, a lamination method, etc. The resin film before lamination used in the lamination method by a pressing method, a lamination method, etc. may have a single layer structure or a multilayer structure. The intermediate film 3 can be formed of a single layer in addition to being formed of multiple layers as described above.

[0037] The intermediate film 3 according to this embodiment is formed by stretching the intermediate film 3, which has a rectangular shape in plan view after molding, with a roller so that the lower side is longer. Hereinafter, this process will be referred to as a stretching process and will be described in detail. In addition, the intermediate film before the stretching process will be referred to as a pre-stretched intermediate film, and the intermediate film after the stretching process will be referred to as a stretched intermediate film.

[0038] As shown in FIG. 3, the stretching process is performed by passing the pre-stretched intermediate film between two cone-shaped rollers 91, 92. Here, the upper roller is referred to as the first roller 91, and the lower roller is referred to as the second roller 92. In addition, the axial end of each roller 91, 92 with a larger diameter is referred to as the first end 911, 921, and the axial end with a smaller diameter is referred to as the second end 912, 922. The first roller 91 and the second roller 92 are arranged so that the rotation axes G1, G2 are parallel to each other. In addition, the first end 911, 921 and the second end 912, 922 of both rollers 91, 92 are arranged so that they are on the same side. As a result, a gap 900 is formed between both rollers 91, 92, which is narrow on the first end 911, 921 side and wide on the second end 912, 922 side.

[0039] Therefore, when the pre-stretched intermediate film is passed between these rollers 91, 92, as shown in Fig. 4, the peripheral speed of the first end 911, 921 side of each roller 91, 92 is high, so that the pre-stretched intermediate film is stretched at the first end 911, 921 side. As a result, a stretched intermediate film 3 having a trapezoidal shape in a plan view is formed. Also, as shown in Fig. 3, a gap 900 is formed between both rollers 91, 92, so that the cross section of the stretched intermediate film 3 is thicker at the first end 911, 921 side and thinner at the second end 912, 922 side. As a result, an intermediate film 3 is formed in which the upper end surface 311 is thick and the lower end surface 312 is thin.

[0040] <4. Shielding layer> As shown in Fig. 1, a shielding layer 4 is laminated on the periphery of the windshield, which is made of dark colored ceramic such as black. This shielding layer 4 blocks the view from inside and outside the vehicle, and is laminated along the four sides of the windshield.

[0041] The shielding layer 4 may be formed in various forms, such as only the inner surface of the outer glass plate 1, only the inner surface of the inner glass plate 2, or both the inner surfaces of the outer glass plate 1 and the inner glass plate 2. The shielding layer 4 may be formed of various materials, such as ceramics, and may have the following composition, for example. [Table 1] *1, Main components: copper oxide, chromium oxide, iron oxide and manganese oxide *2, Main ingredients: bismuth borosilicate, zinc borosilicate

[0042] The ceramic can be formed by screen printing, but it can also be produced by transferring a firing transfer film to a glass plate and firing it. When using screen printing, for example, the following can be used: polyester screen: 355 mesh, coat thickness: 20 μm, tension: 20 Nm, squeegee hardness: 80 degrees, mounting angle: 75°, printing speed: 300 mm / s. The ceramic can be formed by drying in a drying oven at 150°C for 10 minutes.

[0043] <5. Windshield manufacturing method> Next, a method for manufacturing a windshield will be described. First, a manufacturing line for a glass sheet will be described.

[0044] Here, the forming die will be described in more detail with reference to FIG. 5. FIG. 5 is a plan view of the forming die. As shown in FIG. 5, the forming die 800 is provided with a frame-shaped die body 810 that roughly matches the outer shape of both glass plates 1 and 2. Since the die body 810 is formed in a frame shape, it has an internal space 820 that penetrates in the vertical direction inside. The peripheral parts of both flat glass plates 1 and 2 are placed on the upper surface of the die body 810. Therefore, heat is applied to the glass plates 1 and 2 from a heater (not shown) arranged on the lower side through the internal space. As a result, both glass plates 1 and 2 are softened by the heat and curved downward due to their own weight. Note that a shielding plate 840 for shielding heat may be arranged on the inner peripheral edge of the die body 810, which makes it possible to adjust the heat received by the glass plates 1 and 2. The heater can be arranged not only below the forming die 800 but also above it.

[0045] Next, the forming method will be described with reference to FIG. 6. FIG. 6 is a side view of a furnace through which the forming die passes. First, the above-mentioned shielding layer 2 is laminated on the outer glass sheet 1 and the inner glass sheet 2 before bending. Next, the outer glass sheet 1 and the inner glass sheet 2 are overlapped and passed through a heating furnace 802 as shown in FIG. 6 while being supported by the forming die 800. When heated to near the softening point temperature in the heating furnace 802, both glass sheets 1 and 2 are curved downward from the inner edge portion due to their own weight, and are formed into a curved shape. Next, both glass sheets 1 and 2 are carried from the heating furnace 802 to an annealing furnace 803, where they are annealed. Then, both glass sheets 1 and 2 are carried out of the annealing furnace 803 to be cooled outside.

[0046] Once the outer glass sheet 1 and the inner glass sheet 2 are formed in this manner, the interlayer film 3 is then sandwiched between the outer glass sheet 1 and the inner glass sheet 2. The interlayer film 3 is shaped to be slightly larger than the outer glass sheet 1 and the inner glass sheet 2. As a result, the outer edge of the interlayer film 3 protrudes from the outer glass sheet 1 and the inner glass sheet 2. In addition, the thicker end of the interlayer film 3 is disposed above both glass sheets 1, 2.

[0047] Next, the laminate in which both glass plates 1, 2 and the interlayer film 3 are laminated is placed in a rubber bag and pre-bonded at about 70 to 110°C while suctioning under reduced pressure. Other methods of pre-bonding are also possible, and the following method can also be adopted. For example, the laminate is heated in an oven at 45 to 65°C. Next, the laminate is pressed by a roll at 0.45 to 0.55 MPa. Subsequently, the laminate is heated again in an oven at 80 to 105°C, and then pressed again by a roll at 0.45 to 0.55 MPa. In this way, the pre-bonding is completed.

[0048] Next, the main bonding is performed. The pre-bonded laminate is subjected to the main bonding in an autoclave, for example, at 8 to 15 atmospheres and 100 to 150°C. Specifically, the main bonding can be performed, for example, under conditions of 14 atmospheres and 135°C. Through the above pre-bonding and main bonding, the interlayer film 3 is bonded to each of the glass sheets 1 and 2. Finally, the interlayer film 3 protruding from the outer glass sheet 1 and the inner glass sheet 2 is cut off to produce a windshield having a cross section as shown in FIG. 2. That is, by using the interlayer film 3 having a wedge angle α, a windshield with a wedge angle α is formed. Note that a curved windshield can also be produced by other methods, for example, by press working.

[0049] <6.HUD device> Next, the HUD device will be described. The HUD device projects information such as vehicle speed onto the windshield. However, it is known that when this HUD device is used, a double image is formed by the light projected onto the windshield. That is, the image perceived by reflection on the inner surface (second main surface) of the windshield and the image perceived by reflection on the outer surface (first main surface) of the windshield are perceived separately, resulting in a double image.

[0050] To prevent this, a windshield with a wedge angle α as in this embodiment is used. That is, as shown in Fig. 7, the windshield is formed so that the thickness decreases downward at least in the display area where light is projected from the HUD device 500. This causes the light reflected by the inner surface of the windshield (the second surface 202 of the inner glass plate 2) and entering the vehicle interior to roughly coincide with the light reflected by the outer surface of the windshield (the first surface 101 of the outer glass plate 1) and entering the vehicle interior, thereby eliminating double images.

[0051] Incidentally, the HUD device 500 according to this embodiment is capable of switching the display area in three stages according to the driver's eye height, as shown in FIG. 8 and FIG. 9. That is, the display area can be switched by changing the irradiation angle of light from the HUD device 500 to the windshield. Here, these three display areas are referred to as an upper area 501, a central area 502, and a lower area 503. The display areas 501 to 503 shown in FIG. 9 are seen from the outside of the vehicle, and all have the same size. These three display areas 501 to 503 are arranged vertically and overlap each other. That is, the lower part of the upper area 501 overlaps with the upper part of the lower area 503, and the central area 502 is disposed between the upper area 501 and the lower area 503. Therefore, an area where the three areas 501 to 503 overlap is disposed inside the central area 502.

[0052] The display areas 501-503 are disposed on the right side of the windshield when viewed from the front. That is, the display areas 501-503 are disposed in front of the driver for right-hand drive vehicles (see FIG. 17). Since the windshield is curved in the horizontal direction as described above, when viewed from the front, the upper and lower sides of the display areas 501-503 are inclined downward from left to right in accordance with the curvature, as shown in FIG. 9. It is preferable that the display areas 501-503 are provided in a location on the windshield where the radius of curvature in the horizontal and vertical directions is large. For example, it is preferable that the display areas 501-503 are provided near the center of the windshield in the horizontal direction and at the bottom in the vertical direction.

[0053] <7. Relationship between display area and wedge angle> The present inventors have examined the relationship between the above-mentioned three display areas 501 to 503 and the wedge angle capable of suppressing double images as follows.

[0054] First, a grid as shown in FIG. 10 was set in each display area 501-503, and the double image was measured. The thickness of the outer glass plate 1 and the inner glass plate 2 was 2 mm, and the thickness of the thinnest part of the interlayer 3 was 0.76 mm. The grid in FIG. 10 is seen from the inside of the vehicle. In this grid, six points A-G are arranged in the vertical direction, and six lines 1-6 are arranged in the horizontal direction (total of 36 lines). Then, the range of wedge angles (allowable wedge angles) in which the amount of deviation due to the double image of the 36 lines A-1-G-6 in the grid is within 2 mm was calculated by simulation. The results are shown in FIG. 11-FIG. 13.

[0055] The graph in FIG. 11 shows the simulation results in the upper region 501, with the horizontal axis indicating the vertical position on the windshield and the vertical axis indicating the wedge angle. However, for the sake of convenience, FIG. 11 only shows the upper and lower limit values ​​of the allowable wedge angle for each of the lines A-1 to G-6. According to FIG. 11, in each of the rows A to G arranged in the vertical direction, the allowable wedge angle of the lines 1 to 6 increases from 1 to 6. That is, in the upper region 501, the range of the allowable wedge angle increases from the left side to the right side (pillar side) as viewed from the inside of the vehicle. Also, the range of the allowable wedge angle decreases from row A to row G arranged in the vertical direction. That is, in the upper region 501, the range of the allowable wedge angle decreases the further down you go. And in FIG. 11, the upper limit value of the allowable wedge angle is minimum at the location where the line G-1 is arranged.

[0056] Fig. 12 shows the simulation results for the central region, and Fig. 13 shows the simulation results for the lower region. The central region 502 and the lower region 503 show the same tendency as the upper region 501. In Fig. 13, the lower limit of the allowable wedge angle is maximum where the line A-6 is located.

[0057] Fig. 14 is a combination of Figs. 11 to 13. It can be seen from Fig. 14 that the range of the allowable wedge angle increases from the upper region 501 to the lower region 503. Fig. 14 also shows that the allowable wedge angle common to all display regions 501 to 503 has an upper limit at the wedge angle at line G-1 in the upper region and a lower limit at line A-6 in the lower region. Therefore, by setting the wedge angle within this range (hereinafter referred to as the limited allowable wedge angle), it is possible to suppress the occurrence of double images in all display regions 501 to 503.

[0058] However, since the range of the limited allowable wedge angle is narrow, it is not easy to manufacture a windshield with such a wedge angle. The area where this limited allowable wedge angle is required is an area including G-1 and A-6 in the vertical direction, and is an area where three display areas 501 to 503 overlap (hereinafter referred to as the limited area), as shown in FIG. 15. On the other hand, as shown in FIG. 14, in the upper area 501 and the lower area 503, the range of the allowable wedge angle is larger than the range of the limited allowable wedge angle. Therefore, in order to suppress the occurrence of double images in all the display areas 501 to 503, it is not necessary to satisfy the limited allowable wedge angle in all the display areas 501 to 503, and it is sufficient that the limited allowable wedge angle is satisfied at least in the limited area. Therefore, the inventor set the allowable wedge angle as follows.

[0059] First, as shown in FIG. 16, the vertical length of the area including all the display areas 501-503 (hereinafter referred to as the entire display area) is defined as Y. Next, a line X passing through the midpoints R1 and R2 of both sides of the entire display area is defined, and a line parallel to the line X and 0.15Y away from the line X in the upward direction and a line 0.15Y away from the line X in the downward direction are defined, and the area between them is defined as a first area 701. Also, the area between the line passing through the upper side of the entire display area and a line parallel to the upper side and 0.3Y away from the upper side in the downward direction is defined as a second area 702. Furthermore, the area between the line passing through the lower side of the entire display area and a line parallel to the lower side and 0.3Y away from the lower side in the upward direction is defined as a third area 703.

[0060] It was then found that if the ranges of allowable wedge angles in the first region 701, the second region 702, and the third region 703 are defined as S_Center, S_Upper, and S_Lower, respectively, these should satisfy the following equations (1) and (2). S_Center <S_Upper (1) S_Center <S_Lower (2)

[0061] FIG. 17 is a diagram showing the left side of the windshield as viewed from the outside of the vehicle. To satisfy the above formulas (1) and (2), it is necessary to strictly control the wedge angle of at least the portion of the interlayer film 3 that is arranged in the first region 701. That is, the wedge angle of the interlayer film 3 in this portion needs to be at S_Center. On the other hand, the wedge angles of the second region 702 and the third region 703 are in a range wider than S_Center, so strict control is not necessary. Note that the interlayer film 3 originally has a variation in thickness, and this variation causes waviness on the surface of the interlayer film 3. This waviness remains even after the windshield is assembled. Therefore, for example, if the windshield is assembled so that the portion of the interlayer film 3 with the smallest waviness is arranged in the first region 701, the above formulas (1) and (2) can be satisfied.

[0062] In the above simulation, for example, the height of each of the display regions 501 to 503 is about 120 mm, the width is about 100 mm, the height in the vertical direction of the overlapping portion of the upper region 501 and the lower region 503 is about 64 mm, and Y is about 177 mm. In this case, as a specific allowable wedge angle range in which the amount of deviation due to double images is within 2 mm, S_Center can be, for example, 0.05 mrad or more and 0.10 mrad or less. S_Upper can be, for example, 0.15 mrad or more and 0.45 mrad or less. S_Lower can be, for example, 0.20 mrad or more and 0.55 mrad or less. However, these are merely examples, and it is sufficient that at least the above formulas (1) and (2) are satisfied.

[0063] In the above example, the upper limit of the amount of misalignment due to double images is set to 2 mm, but this is not particularly limited and can be set appropriately according to requirements. Therefore, regardless of the upper limit of the amount of misalignment due to double images, if a windshield can be manufactured that satisfies the above formulas (1) and (2) according to the set upper limit, double images can be suppressed.

[0064] When actually measuring the wedge angle, a plurality of lattice points with a pitch of 20 mm or less are defined in each of the regions 701 to 703. The number of lattice points depends on the size of each of the regions 701 to 703, but the maximum number of lattice points that can fit in each of the regions 701 to 703 is set. Then, the wedge angle of each lattice point is measured by an interferometer, and the difference between the maximum and minimum allowable wedge angles in each of the regions 701 to 703 is set as S_Center, S_Upper, and S_Lower, respectively. Alternatively, each of the regions 701 to 703 may be cut in the height direction so as to divide the horizontal direction into approximately five equal parts, and three points may be selected at equal intervals within each of the regions 701 to 703 for each cross section obtained by cutting, and the height may be measured with a microscope to obtain the wedge angle.

[0065] <8.Features> As described above, the windshield according to this embodiment can suppress double images in all three display regions 501 to 503. In this case, there is no need to strictly control the wedge angle of the interlayer film 3 in the portions that are to be arranged in all of the display regions 501 to 503. The wedge angle of the interlayer film 3 can be strictly controlled only in the portion where the first region 701, which has the narrowest allowable wedge angle range, is arranged, and the control of the wedge angle of the interlayer film 3 can be loosened in the other regions 702 and 703 compared to the first region 701, making manufacturing easier.

[0066] <9. Variations> Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the present invention. In addition, the following multiple modified examples can be appropriately combined.

[0067] <9-1> In the above embodiment, an example of the HUD device 500 capable of switching the display area in three stages has been described. However, even if a HUD device 500 capable of switching the display area in two stages other than three stages or in four or more stages is used, double images can be suppressed in all display areas as long as the above formulas (1) and (2) are satisfied.

[0068] <9-2> In the above embodiment, the intermediate film 3 is formed in a wedge shape, but since it is sufficient for the windshield as a whole to be formed in a wedge shape, it is sufficient for at least one of the outer glass plate 1, the inner glass plate 2, and the intermediate film 3 to be formed in a wedge shape.

[0069] <9-3> There are no particular limitations on the shape of the shielding layer 4, and various shapes are possible. For example, the shielding layer may be formed with a window (opening) so that light can be irradiated by a sensor or the outside can be photographed by a camera.

[0070] <9-4> In the above embodiment, a laminated glass having an outer glass plate 1, an inner glass plate 2, and an interlayer film 3 is used as the glass plate of the present invention, but the present invention is not limited to this and may be a single plate. [Explanation of symbols]

[0071] 2. Imaging Device 10 Glass Plate 110 Shielding layer 113 Shooting window (opening)

Claims

1. A windshield provided with a HUD device capable of switching between a plurality of display areas in the up and down directions, a glass plate having a first main surface and an opposite second main surface, the display area being formed thereon; the glass plate is configured so that an upper end portion has a thickness greater than a lower end portion, and thus the first main surface and the second main surface form an allowable wedge angle α; The vertical height of the entire display area including all of the plurality of display areas is designated as Y, The range of the allowable wedge angle α in the first region between a line 0.15Y above a line passing through the center of the vertical direction of both sides of the entire display region and a line 0.15Y below the line is defined as S_Center, The range of the allowable wedge angle α in the second region between the upper side of the entire display region and a line 0.3Y downward from the upper side is defined as S_Upper, If the range of the allowable wedge angle α in the third region between the lower side of the entire display region and a line 0.3Y above the lower side is S_Lower, A windshield that satisfies S_Center<S_Upper and S_Center<S_Lower.

2. The windshield of claim 1 , wherein the display areas are configured to overlap vertically.

3. 3. The windshield according to claim 1, wherein the windshield is curved so as to be convex toward the outside of the vehicle in the horizontal direction.

4. A plurality of regions having different radii of curvature in the horizontal direction; The windshield according to claim 3 , wherein the display area is provided in the area having the large radius of curvature in the horizontal direction.

5. 5. The windshield according to claim 1, wherein the windshield is curved so as to be convex toward an outside of the vehicle in the vertical direction.

6. The vertical direction has a plurality of regions having different radii of curvature, The windshield according to claim 5 , wherein the display area is provided in the area having the large radius of curvature in the vertical direction.

Images