JPH11151978A - Mirror for vehicle and mirror surface shape setting method of mirror for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To widen a visual field in tow directions or more. SOLUTION: A reverse side of a glass base board 11 is taken as a mirror surface with a reflecting film formed on it. In this mirror surface, a most part except a lower side and right side is formed as a spherical part 11b, with a part except that as a non-spherical part 11c. Of this nonspherical part 11c, a little upper part in a right side is formed as a first nonspherical part 11cA gradually changing curvature in a right direction, a part from a right side thereof over to a lower part is formed as a second non-spherical part 11cB gradually changing curvature diagonally to the downward, and a part in a left side in the lower part is formed as a third nonspherical part 11cC gradually changing curvature to the downward. These spherical part 11b and first/second/ third nonspherical part 11cA, 11cB, 11cC are mutually continued.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle mirror provided with a spherical surface and an aspherical surface on a mirror surface, and a method of setting a mirror surface shape of the vehicle mirror.

[0002]

FIG. 11 shows a glass substrate 1 which is a mirror body of a conventional vehicle mirror.
A reflection film is formed on the back surface of the glass substrate 1 to form a mirror surface 1a.
It is said. FIG. 12 shows a cross section of the glass substrate 1.
As can be seen from FIG. 12, a large portion on the left side (the portion on the vehicle body side) is a spherical portion 1b, and a right portion is an aspherical portion 1c.
It has been. The spherical portion 1b and the aspherical portion 1c increase the visual field range. In particular, the aspherical portion 1c further expands the visual field range by gradually changing the radius of curvature. Therefore, a wider field of view can be obtained as compared with a mirror having only a spherical surface.

The surface shape of the mirror surface 1a is set by the following method. That is, as shown in FIG. 13, a curve L composed of an arc portion L1 having a certain curvature and a non-arc portion L2 continuous with the arc portion L1
The curve L is rotated, for example, once around a center of curvature P of the arc portion L1 and a center line K passing through the arc portion L1 (see FIG. 14). Thus, a curved surface F having the spherical surface portion F1 and the aspherical surface portion F2 continuously is formed (see FIG. 15). The mirror shape is set by cutting out a predetermined area Fr of the curved surface F.

[0004] However, the conventional technique described above has a problem that a wide field of view can be obtained only in the right part, and the field of view in other parts is not enlarged. The curved surface F
Of the predetermined area portion Fr in the section (cutout point)
However, since the boundary shape between the spherical surface portion F1 and the aspherical surface portion F2 is a single circle, it is difficult to balance the visual field, and it is unavoidable to expand the visual field only in one direction as shown in FIG. That was the fact.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a vehicle mirror and a method of setting a mirror surface shape of the vehicle mirror that can expand the field of view in two or more directions.

[0006]

According to a first aspect of the present invention, there is provided a vehicle mirror, comprising: a spherical portion; an aspherical portion which is continuous with the spherical portion and whose curvature is varied in a predetermined direction; And a mirror surface having another aspherical portion whose curvature changes in a different direction from the aspherical portion. In this configuration, since a plurality of aspherical portions are provided, the field of view can be expanded in two or more directions, for example, in the horizontal and vertical directions.

According to a second aspect of the present invention, there is provided a method for setting a mirror surface shape of a vehicle mirror, wherein a curved line including an arc portion and a non-arc portion connected to the arc portion is obtained by obtaining the mirror surface shape described above.
Rotate around a rotation axis passing through the center of curvature of the arc portion of the curve and a predetermined portion of the arc portion, and, the rotation axis,
The curve is moved so as to pass through the center of curvature of the arc portion of the curve and pass through a portion different from the predetermined portion of the arc portion of the curve, rotate the curve about the rotation axis, and obtain the rotation locus of the curve. It is characterized in that a predetermined area of the curved surface is set to a mirror surface shape.

According to this, unlike the case where the aspherical portion is formed by a single rotation axis, a plurality of aspherical portions whose curvatures are varied in different directions can be continuously formed. The degree of freedom of the boundary shape is high, and the visual field balance with the spherical portion can be favorably achieved. In this case, since the rotation axis is moved so as to pass through the center of curvature of the arc portion of the curve, the spherical portion is normally formed and the plurality of aspherical portions are formed despite the rotation axis being moved. Also, the curvature is sequentially changed to form a smooth continuous surface.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. FIGS. 1 and 2 show a glass substrate 11 which is a mirror main body of a vehicle mirror. The back surface of the glass substrate 11 is a mirror surface 11a on which a reflection film is formed. In the mirror surface 11a, most of the mirror surface except the lower side and the right side is formed in the spherical portion 11b, and the other portions are formed in the aspherical portion 11c.
Of the aspherical portion 11c, a slightly upper portion on the right side is
It is formed as a first aspherical portion 11cA in which the curvature changes (gradually decreases) in the right direction, and a portion from the right side to the lower portion thereof serves as a second aspherical portion 11cB in which the curvature changes obliquely downward. The lower left portion is formed as a third aspherical portion 11cC whose curvature changes downward. Each aspherical portion 11cA, 11cB, 1
The boundary of 1cC is indicated by a two-dot chain line. These spherical parts 1
1b, first aspherical portion 11cA, second aspherical portion 11c
B, the third aspherical portion 11cC is continuous with each other.

A method for setting the shape of the mirror surface 11a will be described. As shown in FIG. 3, consider a curve L including an arc portion L1 having a certain curvature and a non-arc portion L2 whose curvature continuously changes (gradually decreases), and a curve L for rotating the curve L is considered. Consider the center line Ka. And this center line Ka
From the center P of the arc portion L1 to the portion La where the arc portion L1 is located.
Through the center line Ka and the curve L
Is rotated by a predetermined angle α in the direction of arrow S from FIG.
reference). As a result, a partial spherical portion Qa and a partial aspherical portion Ra are formed.

Next, the center line Ka is shown in FIGS. 5 and 6 (FIG. 6).
Move the center line Ka of the arc portion L1 and the portion Lb of the arc portion L1 that is different from the portion La as shown in the plan view of the center lines Ka and Kb (after the movement). The rotation axis is indicated by the symbol Kb). From this state, as shown in FIG. 7, the curve L is rotated about the center line Kb by an angle β in the direction of arrow T. Thus, a partial spherical portion Qb and a partial aspherical portion Rb are formed.

Next, as shown in FIG. 8, the center line Kb is
The curved part L1 is moved so as to pass through the center P of the circular part L1 and the part Lc of the circular part L1 of the rotated curve L (the center line after the movement is indicated by the symbol Kc). The curve L is centered on the center line Kc by a predetermined angle γ in the direction of arrow U from FIG.
Rotate. As a result, a partial spherical portion Qc and a partial aspherical portion Rc are formed.

As described above, the curved surface Fqr as shown in FIG.
Is formed. In FIG. 9 and FIG. 10, which will be described later, each surface portion is shown in an enlarged manner. In the curved surface Fqr, the partial spherical portions Qa, Qb, and Qc form a spherical portion Q, and the partial aspheric portions Ra, Rb, and Rc form a continuous aspheric portion R, The spherical surface portion Q and the aspherical surface portion R are also continuous. In this case, the shape of the boundary E between the spherical surface portion Q and the aspherical surface portion R is not circular but non-circular (for example, a shape close to an elliptical shape). An arbitrary shape can be obtained by changing.

Thereafter, a predetermined area portion FE of the curved surface Fqr
The mirror shape is set by cutting out (see FIG. 10). Thereby, the glass substrate 11 shown in FIG.
Are set, and the spherical portion 11b is
FIG. 9 shows the spherical portion Q in FIG.
1cA, second aspherical portion 11cB, third aspherical portion 11
cC is an aspheric surface part Ra, Rb, Rc, respectively.

According to this embodiment, the spherical portion Q
And a predetermined direction (in this case, a lateral direction) connected to the spherical portion Q.
A first aspherical surface portion 11cA whose curvature is varied, and the aspherical surface portion Ra connected to the spherical surface portion Q and the aspherical surface portion 11cA.
A mirror surface 11 having a second aspherical portion 11cB whose curvature changes in a different direction (obliquely downward) and a third aspherical portion 11cC whose curvature changes further in a different direction (downward).
a is formed. Thus, for example, the field of view can be expanded in the horizontal direction, the obliquely downward direction, and the vertical direction.

In this case, regarding the setting of the shape of the mirror surface 11a, an arc portion L1 and a non-arc portion L2 connected to the arc portion L1
Is rotated about a rotation axis Ka passing through the center of curvature P of the arc portion L1 of the curve L and a predetermined portion La of the arc portion L1, and thereafter, the rotation axis Ka is
Is moved upward, the curve L is rotated about the rotation axis Kb after the movement, and further, the rotation axis Kb is moved on the curve L, and the curve L is rotated about the rotation axis Kc after the movement. Rotate to form a curved surface Fqr obtained from these rotation trajectories, and a predetermined area of the curved surface Fqr is
Since the surface shape is set to 1a, a plurality of aspherical portions Ra, Rb, and Rc whose curvatures change in different directions are different from each other, unlike the case where the aspherical portion is formed by a single rotation axis. Further, the degree of freedom of the boundary shape with the spherical surface portion Q is high, and the visual field balance with the spherical surface portion Q can be favorably achieved.

In this case, since the rotation axes Ka, Kb, and Kc are all moved so as to pass through the center of curvature P of the arc portion L1 of the curve L, the spherical portion Q is normal despite the movement of the rotation axis. And the aspherical portions Ra, Rb, and Rc also gradually change their curvatures to form a smooth continuous surface. In addition,
9 and 10, the boundary between the spherical portion Q and the aspherical portions Ra, Rb, and Rc is described on the spherical surface Fqr for convenience. Thus, there are no boundaries.

[0018]

As apparent from the above description, the present invention has the following effects. According to the first aspect of the present invention, since the spherical portion is provided with the aspherical portion whose curvature is continuously varied in a plurality of directions, the field of view can be expanded in a plurality of directions.

According to the second aspect of the present invention, unlike the case where the aspherical portion is formed by a single rotation axis, the aspherical portion whose curvature changes in different directions can be smoothly and continuously formed. The degree of freedom of the shape of the boundary with the spherical portion is high, and the field of view and the spherical portion can be well balanced.

[Brief description of the drawings]

FIG. 1 is a front view of a glass substrate showing one embodiment of the present invention.

FIG. 2 is a cross-sectional plan view

FIG. 3 is a conceptual diagram of a relationship between a curve L and a center line Ka as viewed from the side.

FIG. 4 is a conceptual diagram showing the relationship in a three-dimensional manner.

FIG. 5 is a conceptual diagram of a curved surface formed by rotating the curve L about the center line Ka in a three-dimensional manner.

FIG. 6 is a conceptual diagram of a relationship between a curve L and center lines Ka and Kb as viewed from above.

FIG. 7 is a conceptual diagram of a curved surface formed by rotating the curve L about the center line Kb in a three-dimensional manner.

FIG. 8 is a conceptual diagram of a curved surface formed by rotating the curve L about the center line Kc as viewed three-dimensionally.

FIG. 9 is a conceptual diagram showing a formed curved surface in a three-dimensional manner in an enlarged manner.

FIG. 10 is a three-dimensional conceptual diagram showing a state of cutting out a mirror surface shape.

FIG. 11 is a diagram corresponding to FIG. 1 showing a conventional example.

FIG. 12 is a diagram corresponding to FIG. 2;

FIG. 13 is a conceptual diagram of the relationship between the curve L and the center line K viewed from above.

FIG. 14 is a conceptual diagram of a curved surface formed by the rotation of the curve L as viewed three-dimensionally.

FIG. 15 is a three-dimensional conceptual diagram showing a state of cutting out a mirror surface shape.

[Explanation of symbols]

11 is a glass substrate, 11a is a mirror surface, 11b is a spherical portion, 1
1c is an aspherical portion, 11cA is a first aspherical portion, 11cB
Is a second aspherical portion, 11cC is a third aspherical portion, L is a curve, L1 is an arc portion, L2 is an aspheric portion, Ka, Kb, and Kc.
Indicates a center line, and Fqr indicates a curved surface.

Claims (2)

[Claims] 1. A spherical part, an aspheric part connected to the spherical part and having a curvature varying in a predetermined direction, and a curvature connected to the spherical part and the aspheric part and having a curvature varying in a direction different from the aspheric part. A mirror for vehicles, comprising a mirror surface having another aspherical portion. 2. A method for obtaining a surface shape of a mirror surface of a vehicle mirror according to claim 1, wherein a curve formed by an arc portion and a non-arc portion connected to the arc portion is formed by a curvature center of the arc portion of the curve and the arc. Rotating about a rotation axis passing through a predetermined portion of the curve, and moving the rotation axis so as to pass through a center of curvature of an arc portion of the curve and pass a different portion of the arc portion of the curve from the predetermined portion. Wherein the curve is rotated about the rotation axis, and a predetermined area of the curved surface obtained by the rotation locus of the curve is set to a mirror surface shape.