Glass
Glass having an inner surface and an outer surface, includes a first area used by a head-up display, and a second area adjacent to the first area, and not used by the head-up display. Representing an area closest to a boundary between the first area and the second area in the first area, by an edge on the boundary side in the first area, and representing an area closest to the boundary in the second area, by an edge on the boundary side in the second area, a requirement is that a wedge angle δ formed by the inner surface and the outer surface satisfies a predetermined formula.
1. A windshield glass, comprising:
a glass having an inner surface, an outer surface, a first area used by a head-up display installed inside a vehicle, a second area adjacent to the first area, and a wedge angle δ at each point in a partial area of the second area including the edge on the boundary side in the second area such that the second area is not used by the head-up display, an edge on the boundary side in the first area represents an area closest to a boundary between the first area and the second area in the first area, and an edge on the boundary side in the second area represents an area, closest to the boundary in the second area,
wherein the glass is configured to be installed on the vehicle in a position with respect to the head-up display such that the glass has a local incident angle φ of a ray of light emitted in an X-direction designating a front-and rear direction of the vehicle from a light source outside the vehicle to the eyes of a driver in the vehicle and incident on the outer surface of the glass, and that the glass has the wedge angle δ determined by Formula (1),
δ
=
t
R
sin
φcosφ
n
2
-
sin
2
φ
-
η
cos
φ
2
n
2
-
sin
2
φ
(
1
)
where the wedge angle δ is formed by the inner surface and the outer surface and excludes a case of a uniform wedge angle δ, t represents a thickness of the glass, R represents a local curvature radius of the glass, n represents a refractive index of the glass, and when η h is determined by Formula (2),
η
h
=
2
t
R
sin
φ
n
2
-
sin
2
φ
-
2
δ
h
n
2
-
sin
2
φ
cos
φ
(
2
)
where η h is an angle of perspective double images generated by the light from the light source and observed by the driver inside the vehicle at the edge on the boundary side in the first area, δ h represents a wedge δ angle at the edge on the boundary side in the first area, η is an arbitrary value having a same sign as a sign of η h and satisfies conditions of being less than or equal to a smaller one of 2|η h | and 9 if |η h |≤9 and being less than or equal to |η h | if |η h |>9, η is not 0 at all points in the part of the area, and 0<|η| is satisfied at the edge on the boundary side in the second area.
2. The windshield glass as claimed in claim 1 , wherein in the second area that includes the edge on the boundary side in the second area, at each point in an area excluding a periphery of the glass, the wedge angle δ formed by the inner surface and the outer surface satisfies Formula (1).
3. The windshield glass as claimed in claim 1 , wherein at each point in an entire area of the second area that includes the edge on the boundary side in the second area, the wedge angle δ formed by the inner surface and the outer surface satisfies Formula (1), where η is an arbitrary value that satisfies 0≤|η|≤9 and η is not 0 at all points in the entire area.
4. The windshield glass as claimed in claim 1 , wherein at each point in an entire area of the second area that includes the edge on the boundary side in the second area, the wedge angle δ formed by the inner surface and the outer surface satisfies Formula (1), where η is an arbitrary value that satisfies 0≤|η|≤6, and η is not 0 at all points in the entire area.
5. The windshield glass as claimed in claim 1 , wherein at each point in an entire area of the second area that includes the edge on the boundary side in the second area, the wedge angle δ formed by the inner surface and the outer surface satisfies Formula (1), where η is an arbitrary value that satisfies 0≤|η|≤3, and η is not 0 at all points in the entire area.
6. The windshield glass as claimed in claim 1 , wherein the glass comprises a first glass plate forming the inner surface, a second glass plate forming the outer surface of the glass, and an intermediate film interposed between the first glass plate and the second glass plate.
7. The windshield glass as claimed in claim 2 , wherein the glass comprises a first glass plate forming the inner surface, a second glass plate forming the outer surface of the glass, and an intermediate film interposed between the first glass plate and the second glass plate.
8. The windshield glass as claimed in claim 3 , wherein the glass comprises a first glass plate forming the inner surface, a second glass plate forming the outer surface of the glass, and an intermediate film interposed between the first glass plate and the second glass plate.
9. The windshield glass as claimed in claim 4 , wherein the glass comprises a first glass plate forming the inner surface, a second glass plate forming the outer surface of the glass, and an intermediate film interposed between the first glass plate and the second glass plate.
10. The windshield glass as claimed in claim 5 , wherein the glass comprises a first glass plate forming the inner surface, a second glass plate forming the outer surface of the glass, and an intermediate film interposed between the first glass plate and the second glass plate.
11. The windshield glass as claimed in claim 1 , wherein the glass comprises a first glass plate forming the inner surface, a second glass plate forming the outer surface of the glass, and an intermediate film interposed between the first glass plate and the second glass plate, the first glass plate has a uniform thickness, and the second glass plate has a uniform thickness.
12. A vehicle, comprising the windshield glass of claim 1 .
13. A vehicle, comprising the windshield glass of claim 2 .
14. A vehicle, comprising the windshield glass of claim 3 .
15. A vehicle, comprising the windshield glass of claim 4 .
16. A vehicle, comprising the windshield glass of claim 5 .
17. A vehicle, comprising the windshield glass of claim 6 .
18. A vehicle, comprising the windshield glass of claim 11 .
19. The windshield glass as claimed in claim 6 , wherein at least one of the first glass plate and the second glass plate comprises inorganic glass, and the intermediate film comprises transparent resin.
20. A vehicle, comprising the windshield glass of claim 19 .