JP2004101829A - Head-up display for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a head-up display for vehicle in which a concave mirror can be made small in size while suppressing distortion of a virtual image formed in front of a windshield glass by devising the profile of a reflecting face of the concave mirror. <P>SOLUTION: The profile of the concave mirror 4 is designed in such a manner that focal distances f1, f2, f3 of guide curve 42, upper guide curve 43 and lower guide curve 44 as the intersection lines of the concave mirror 4 and three planes H1, H2, H3 almost in the horizontal direction and parallel to one another, respectively, satisfy the relation of f1≠f2≠f3 and f1<f2 and f1<f3. Thus, the concave mirror 4 can be made smaller in size than a concave mirror 40 of a conventional head-up display while distortion of the virtual image formed in front of the windshield glass 5 can be suppressed. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a head-up display for a vehicle.
[0002]
[Prior art]
Conventionally, as this kind of head-up display, there is a display as disclosed in Japanese Utility Model Laid-Open No. 62-197175 or Japanese Patent No. 2992114. In this head-up display, the display is disposed on the back side of the dashboard located below the windshield glass in the cabin of the vehicle. Further, the concave mirror has a concave reflecting surface facing both the portion corresponding to the driver's field of view and the display surface of the indicator on the interior side surface of the windshield glass, so that the vehicle is positioned below the windshield glass. Are arranged at a predetermined angle with respect to the vertical direction.
[0003]
Under such a configuration, light representing display information from the display surface of the display device is reflected by the concave surface of the concave mirror and is incident on the interior surface of the windshield glass. The information is reflected on the surface in the line of sight of the driver, and the display information is formed as a virtual image in front of the surface. In other words, the driver visually recognizes the display as if there is a display surface of the display in front of the windshield glass. This makes it possible to minimize the amount of movement of the line of sight for the driver to read the display information while driving the vehicle.
[0004]
By the way, the role of the concave mirror in the above-mentioned head-up display is to reflect light representing display information from the display surface of the display toward the windshield glass, and the image on the display surface can be reliably visually recognized by the driver. It is two of expanding to size. That is, the size of the virtual image on the display surface visually recognized by the driver is larger than the size of the actual display surface. This makes it possible to reduce the size of the display surface, that is, the display, and improve the mountability on a vehicle.
[0005]
The shape of the concave mirror is generally formed as a hyperboloid of revolution.
[0006]
Here, usually, the windshield glass mounted on the vehicle has a curved surface shape, and the curvature thereof is not uniform over the entire windshield glass but is partially different. That is, the vehicle has a symmetrical shape based on the center in the left-right direction of the vehicle, and the curvature increases from the center in the left-right direction of the vehicle toward both ends. In other words, the windshield glass 5 is formed such that the radius of curvature becomes smaller from the center in the left-right direction of the automobile toward both ends. For this reason, in the head-up display, if the concave mirror and the display are simply arranged according to the relationship with the position of the windshield glass as described above, the virtual image will be distorted, and the driver will not be able to see the virtual image. There is a problem that the image is difficult to read, in other words, the display information is difficult to read.
[0007]
As a countermeasure, for example, in a head-up display disclosed in Japanese Patent Application Laid-Open No. 2002-31774, the distortion of the virtual image is reduced by appropriately setting the change in the curvature of the reflecting surface of the concave mirror in accordance with the change in the curvature of the windshield glass. It has been proposed to keep it small.
[0008]
[Problems to be solved by the invention]
Incidentally, the concave mirror and the indicator, which are components of the head-up display, are arranged on the back side of the dashboard located below the windshield glass. In the space behind the dashboard, in addition to the concave mirror and the display, an indoor air conditioner, a display panel for various meters and warnings, an operation panel having various operation switches, and the like are arranged in a complicated manner. Since it is necessary to secure a sufficient occupant's living space in the vehicle cabin, it is very difficult to enlarge the space behind the dashboard. Therefore, there is also a strong demand for miniaturizing the concave mirror (especially, reducing the size of the vehicle in the height direction) in order to improve the mountability of the head-up display for vehicles.
[0009]
However, in the above-mentioned Japanese Patent Application Laid-Open No. 2002-31774, although there is a description of a means for suppressing the distortion of the virtual image, there is no mention of miniaturization of the concave mirror.
[0010]
In view of the above, the present invention has been devised in order to address the above-described problem, by devising the shape of the reflecting surface of the concave mirror to reduce the distortion of the virtual image formed in front of the windshield glass, and to reduce the size of the concave mirror for vehicles. An object is to provide a head-up display.
[0011]
[Means for Solving the Problems]
The present invention employs the following technical means to achieve the above object.
[0012]
A vehicle head-up display according to claim 1 of the present invention is a display that is disposed behind an instrument panel located below a windshield glass in a vehicle interior of a vehicle and emits display light representing display information. And a concave mirror for reflecting the display light from the display toward the windshield glass through the opening of the dashboard by the concave reflection surface, and reflecting the display light from the display by the concave mirror to the windshield glass. A head-up display that reflects the incident light in the direction of the driver's line of sight with the windshield glass and allows the driver to visually recognize the display information as a virtual image formed in front of the windshield. The above-mentioned concave mirror has a concave optical axis plane which is a plane including incident light and reflected light of light on the optical axis of display light on the concave mirror. A guide including a reference curve which is an intersection line with the mirror and a normal line of the concave mirror at a point of incidence of light on the optical axis to the concave mirror, and which is an intersection line between a guide plane which is a plane orthogonal to the optical axis plane and the concave mirror. A curved line, an upper guide curve which is an intersection line between a concave plane and a plane parallel to the guide plane and located above the guide plane, and an intersection line between a plane parallel to the guide plane and located below the guide plane and the vehicle. The lower curve is a free-form surface including a lower guide curve, the reference curve is formed in an arc shape or a hyperbolic shape, the guide curve, the upper guide curve and the lower guide curve are formed in a parabolic shape, and the focal length of the guide curve is , The focal length of the upper guide curve and the focal length of the lower guide curve. By forming the shape of the concave mirror as described above, it is possible to reduce the size of the concave mirror while suppressing the distortion of the virtual image formed in front of the windshield glass, as compared with a conventional head-up display for a vehicle. it can.
[0013]
The vehicle head-up display according to a second aspect of the present invention is configured such that the focal length of the guide curve is smaller than the focal length of the upper guide curve and the focal length of the lower guide curve. By forming the shape of the concave mirror as described above, it is possible to reduce the size of the concave mirror while suppressing the distortion of the virtual image formed in front of the windshield glass, as compared with a conventional head-up display for a vehicle. it can.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
A vehicle head-up display according to the present invention will be described below with reference to the drawings, taking an example in which the vehicle head-up display is applied to a head-up display 1 mounted on an automobile.
[0015]
FIG. 1 is a diagram illustrating the configuration of a head-up display 1 according to the present invention. FIG. 2 is a view taken in the direction of the arrow II in FIG. 1 and 2, the left-right direction is the front-rear direction of the vehicle and the left side is the front of the vehicle. In FIG. 1, the right side of the windshield glass 5 is the interior of the automobile. In FIG. 2, the up-down direction is the width direction of the vehicle, that is, the left-right direction, and the upper side is the right side. The driver's seat is on the right side (upward in FIG. 2). That is, the vehicle is a so-called right-hand drive vehicle.
[0016]
The head-up display 1 mainly includes a windshield glass 5, a display 3 that emits display light representing display information (for example, a traveling speed of an automobile), and a display light from the display 3 directed to the windshield glass 5. And a concave mirror 4 that reflects light. The display 3 and the concave mirror 4 are accommodated and fixed inside the main body 2 while maintaining a predetermined positional relationship.
[0017]
As shown in FIG. 1, the main body 2 is attached to the rear side of the dashboard 6 located below the windshield glass 5 in the cabin of the automobile. As shown in FIG. 1, an opening 2 a through which display light from the display 3 reflected by the concave mirror 4 is emitted is formed in an upper portion of the main body 2. The dashboard 6 also has an opening 6 a corresponding to the opening 2 a of the main body 2. Thereby, the display light from the display device 3 reflected by the concave mirror 4 travels toward the windshield glass 5 through the openings 2a and 6a.
[0018]
The display 3 includes, for example, a liquid crystal display (with a backlight), an EL display, a CRT, and the like, displays various kinds of display information on the vehicle as an image, and emits the display light toward the concave mirror 4.
[0019]
The concave mirror 4 is formed of, for example, glass, resin, metal, or the like, and is fixed in the main body 2 so that its reflection surface faces the display 3.
[0020]
The display light from the display 3 is reflected by the concave mirror 4 toward the windshield glass 5 as shown by a dashed line in FIG. It is reflected in the direction toward 7. Here, the viewpoint 7 is the center between both eyes of the driver. Thereby, the driver visually recognizes, as a virtual image 8, images of various display information displayed on the display 3 in front of the windshield glass 5 as shown in FIG.
[0021]
Here, the windshield glass 5 of the vehicle has a curved surface shape similarly to the windshield glass mounted on a normal vehicle. That is, as shown in FIG. 2, the symmetrical shape is formed on the basis of the center of the vehicle in the left-right direction, and the curvature increases from the center of the vehicle in the left-right direction toward both ends. In other words, the windshield glass 5 is formed such that the radius of curvature becomes smaller from the center in the left-right direction of the automobile toward both ends. In the case of a right-hand drive vehicle, the driver is seated on the right side of the center in the left-right direction of the vehicle, as shown in FIG. Therefore, when the driver visually recognizes the virtual image 8, the curvature on the right side of the virtual image area 8 a which is the area on the windshield glass 5 corresponding to the virtual image 8 is larger than that on the center and the left side.
[0022]
Next, the shape of the concave mirror 4 which is a feature of the head-up display 1 according to the present invention will be described with reference to FIG.
[0023]
FIG. 3 is a conceptual diagram illustrating the shape of the concave mirror 4 used in the head-up display 1 according to one embodiment of the present invention.
[0024]
The concave mirror 4 is formed as a free-form surface including four curves, that is, a reference curve 41, a guide curve 42, an upper guide curve 43, and a lower guide curve 44, as shown in FIG. The reference curve 41, the guide curve 42, the upper guide curve 43, and the lower guide curve 44 will be described below.
[0025]
The reference curve 41 is the intersection of the concave mirror 4 with the optical axis plane V, which is a plane including the light on the optical axis A of the display light emitted from the display 3 and entering the concave mirror 4 and the reflected light B thereof. The reference curve 41 is formed in an arc shape. The center of this arc is on the display 3 side of the concave mirror 4. In FIG. 3, a point 45 is an incident point of the light on the optical axis A of the display light emitted from the display 3 to the concave mirror 4.
[0026]
The guide curve 42 is the intersection of the concave mirror 4 and the plane H1 that includes the normal 46 of the concave mirror 4 at the incident point 45 and is orthogonal to the optical axis plane V. The guide curve 42 is formed in a parabolic shape with the incident point 45 as the vertex and opening toward the display 3 side of the concave mirror 4.
[0027]
The upper guide curve 43 is an intersection of the concave mirror 4 and the plane H2 which is located above the plane H1 and is parallel to the plane H1 when the concave mirror 4 is mounted on the vehicle. The upper guide curve 43 is formed in a parabolic shape with the intersection 47 of the upper guide curve 43 and the reference curve 41 as an apex and opening toward the display 3 side of the concave mirror 4.
[0028]
The lower guide curve 44 is an intersection of the concave mirror 4 and the plane H3 which is located below the plane H1 and is in parallel with the plane H1 when the concave mirror 4 is mounted on the vehicle. The lower guide curve 44 is formed in a parabolic shape with the intersection point 48 of the lower guide curve 44 and the reference curve 41 as an apex and opening toward the display 3 side of the concave mirror 4.
[0029]
In FIG. 3, F1, F2, and F3 are the focal points of the guide curve 42, the upper guide curve 43, and the lower guide curve 44, respectively. Therefore, the distance between the incident point 45 and the focal point F1 is the focal length f1 of the guide curve 42, the distance between the intersection 47 and the focal point F2 is the focal length f2 of the upper guide curve 43, and the distance between the intersection 48 and the focal point F3 is the lower guide. The focal length f3 of the curve 44 is obtained.
[0030]
Here, the shapes of the guide curve 42, the upper guide curve 43, and the lower guide curve 44 are such that the focal lengths f1, f2, and f3 of the guide curve 42, the upper guide curve 43, and the lower guide curve 44 are f1 ≠. f2 設定 f3, and f1 <f2 and f1 <f3.
[0031]
Next, the effect of setting the concave mirror 4 in the above-described shape to reduce the size of the concave mirror 4 will be described below.
[0032]
FIG. 4 is an explanatory diagram comparing the sizes of the concave mirror 4 of the head-up display 1 according to the embodiment of the present invention and the concave mirror 40 of the conventional head-up display. 4, a solid line indicates a concave mirror 4 of the head-up display 1 according to an embodiment of the present invention, and a broken line indicates a concave mirror 40 of a conventional head-up display. Here, the shape of the concave mirrors 4 and 40 shown in FIG. 4 is viewed from the direction of the normal 46 at the incident point 45 of the light on the optical axis A of the display light emitted from the display 3 on the optical axis A. Shape. In the head-up display 1 according to the embodiment of the present invention and the conventional head-up display, the same display 3 is used. In designing the concave mirror 4 of the head-up display 1 according to an embodiment of the present invention, the apparent size of the virtual image 8 formed forward and outside of the windshield glass 5 and the maximum distortion rate of the virtual image 8 are conventionally determined. The specifications of the concave mirror 4 are determined so as to be substantially equivalent to the case of the head-up display described above.
[0033]
According to FIG. 4, in the head-up display 1 according to one embodiment of the present invention, the size of the concave mirror 4 is about 90% in the vertical direction of the vehicle and the size in the horizontal direction of the vehicle as compared with the conventional concave mirror 40. It can be seen that the size can be reduced to about 83%.
[0034]
In the head-up display 1 according to the embodiment of the present invention described above, the shape of the concave mirror 4 is set as follows. That is, the focal lengths f1, f2, f3 of the guide curve 42, the upper guide curve 43, and the lower guide curve 44, which are the intersections of the three planes H1, H2, H3, which are substantially horizontal and parallel to each other, and the concave mirror 4. The shape of the concave mirror 4 is set such that f1 ≠ f2 ≠ f3, f1 <f2, and f1 <f3. Accordingly, the concave mirror 4 can be made smaller than the concave mirror 40 of the conventional head-up display while suppressing the distortion of the virtual image 8 formed in front of the windshield glass 5.
[0035]
In the head-up display 1 according to the embodiment of the present invention described above, the magnitudes of the focal lengths f1, f2, and f3 of the guide curve 42, the upper guide curve 43, and the lower guide curve 44 are expressed as f1 {f2}. Although f3 is set, f1 ≠ f2 = f3 may be set.
[0036]
In addition, in the head-up display 1 according to the embodiment of the present invention, the shape of the reference curve 41 is an arc shape, but may be a hyperbolic shape instead of the arc shape.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a configuration of a head-up display 1 according to an embodiment of the present invention.
FIG. 2 is a view on arrow II in FIG.
FIG. 3 is a conceptual diagram illustrating the shape of a concave mirror 4 used in the head-up display 1 according to one embodiment of the present invention.
FIG. 4 is an explanatory diagram comparing the size of a concave mirror 4 of a head-up display 1 according to an embodiment of the present invention and a concave mirror 40 of a conventional head-up display.
[Explanation of symbols]
1 Head-up display (vehicle head-up display)
2 Body 2a Opening 3 Indicator 4 Concave mirror 41 Reference curve 42 Guide curve 43 Upper guide curve 44 Lower guide curve 45 Incident point 46 Normal line 47 Intersection 48 Intersection 5 Windshield glass 6 Dashboard 6a Opening 7 Viewpoint (line of sight) direction)
8 virtual image 40 concave mirror A optical axis B reflected light F1 focal point F2 focal point F3 focal point f1 focal length f2 focal length f3 focal length H1 plane H2 plane H3 plane V optical axis plane

Claims (2)

A display that is disposed behind the instrument panel located below the windshield glass in the vehicle interior and emits display light representing display information;
A concave mirror that reflects display light from the display toward the windshield glass through an opening of the instrument panel by a concave reflection surface,
The display light from the display is reflected by the concave mirror and is incident on the windshield glass, and the incident light is reflected by the windshield glass in a driver's line of sight, and the display information is displayed to the driver. It is a head-up display that is made to be visually recognized as a virtual image formed in front of the windshield,
The concave mirror has a reference curve that is an intersection of an optical axis plane, which is a plane including light incident on the concave mirror and reflected light of the light on the optical axis of the display light, and reflected light, and light on the optical axis. A guide curve including a normal to the concave mirror at the point of incidence on the concave mirror and being a plane intersecting the guide plane and a plane orthogonal to the optical axis plane; and a guide curve parallel to the guide plane and the guide plane. An upper guide curve which is an intersection line between a plane located above the vehicle and the concave mirror, and a lower guide curve which is an intersection line between a plane parallel to the guide plane and below the guide plane and below the vehicle and the concave mirror. And a free-form surface including
The reference curve is formed in an arc shape or a hyperbolic shape,
The guide curve, the upper guide curve and the lower guide curve are formed in a parabolic shape,
The focal length of the guide curve is different from the focal length of the upper guide curve and the focal length of the lower guide curve. The vehicle head-up display according to claim 1, wherein a focal length of the guide curve is smaller than a focal length of the upper guide curve and a focal length of the lower guide curve.

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