JP2008268883A - Head-up display apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a head-up display (HUD) apparatus for projecting a display image excellent in visibility without being affected by outside light. <P>SOLUTION: The HUD apparatus allows an occupant of a vehicle to visually perceive a virtual image of an image light 81 reflected by a windshield 9 after passing through a cylindrical lens 7, wherein the cylindrical lens 7 is inclined against the image light 81 to thereby reflect outside light reflected on the cylindrical lens 7 not to reach an eye range 3 of the occupant of the vehicle. The cylindrical lens is placed such that an action axis direction for an optical action and a horizontal direction (X direction) in a display image agree with each other. Of the cylindrical lens 7, an inclination angle θx and installation depth d are so set to satisfy that the outside light incident at an angle equal to or greater than an interception upper-limit incident angle θu and reflected by a pass-through side does not arrive at the eye range 3, and the outside light incident at an angle equal to or smaller than the interception upper-limit incident angle θu is intercepted by an instrument panel 2 and can not arrive at the cylindrical lens 7. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a head-up display device provided in a moving body such as a vehicle.

  Conventionally, various types of information are emitted as image light from a video projector (liquid crystal display, etc.) that is provided in a moving body (hereinafter referred to as a vehicle) such as an automobile and is arranged inside an instrument panel (hereinafter referred to as an instrument panel) of the vehicle. In addition, a head-up display device (hereinafter referred to as a HUD device) is known in which a driver visually recognizes various information as a virtual image (hereinafter referred to as a display image) by being reflected on the inner surface of the front windshield.

  In this type of HUD device, it is common to display a display image superimposed on the foreground of the vehicle. When the driver visually recognizes the display image, the eyes can be easily focused as much as possible. It is important to project the display image at a position close to the foreground (a position away from the driver's eyes).

  For this purpose, it is necessary to increase the distance between the driver who visually recognizes the display image and the video projector. However, if the distance between the driver who visually recognizes the display image and the video projector is simply increased, there is a problem that the HUD device itself is increased in size.

  In contrast, multiple reflecting mirrors are installed on the optical path between the video projector and the front windshield to bend the optical path, or an enlargement lens is placed between the video projector and the front windshield. Thus, by making the optical path equivalently long, the entire length of the HUD device is suppressed to be small, and the HUD device is downsized (for example, see Patent Document 1).

Here, FIG. 21 is an explanatory diagram showing the principle that the optical path can be equivalently lengthened by a general convex lens as a magnifying lens.
As shown in FIG. 21, when the video projector that displays the video light 100 is arranged at a position closer to the convex lens C than the focal point F of the convex lens C, the display image 101 becomes a virtual image, and the video projector is viewed from the convex lens C. Are displayed in the same direction as that in which they are arranged (ie, an image is created).

  The distance between the center of the convex lens C and the display image 101 visually recognized by the driver is b, the distance between the center of the convex lens C and the portion displaying the image light 100 of the video projector is a, and the focal length of the convex lens C is As f, the distance a, the distance b, and the focal length f have the relationship shown in the equation (1).

That is, as is clear from the equation (1), the projection position of the display image is increased by increasing the distance a between the image projector that displays the image light 100 and the convex lens C within the range from the convex lens C to the focal point F. In other words, the optical path from the video projector to the driver who visually recognizes the virtual image can be equivalently increased.

However, in the HUD device, as shown in FIG. 22, a front windshield 203 exists between the lens 202 (convex lens C) and the driver, and image light is irradiated to the front windshield 203 from below. It has such an arrangement. That is, the driver can visually recognize the image light 100 whose traveling direction has been changed by being reflected by the front windshield 203, and as a result, the virtual image is not under the front windshield 203, which is the same as the image projector, but in the front window. It will appear at a position that has passed through the shield 203.
JP 2002-202475 A

  However, in the HUD device described in Patent Document 1, as shown in FIG. 23, depending on the angle at which external light such as sunlight 200 is incident, the light is transmitted through the front windshield 203 and reflected to the lens 202, and the driver's The reflected light 201 may enter the eye range 204.

As a result, as shown in FIG. 24, since the reflected light 201 is stronger than the light of the display image, there is a problem that the noise becomes unacceptable to the driver and affects the visibility of the display image.
The present invention solves the above-described problems, and can provide a head-up display device that can project a display image with high visibility without being affected by external light, and can further reduce the size of the device. The purpose is to provide.

  The head-up display device according to claim 1, which is an invention made to achieve the above object, is a device mounted on a moving body, and reflects image light by reflecting means that transmits and reflects light. And optical means for optically acting on the light in a predetermined direction and transmitting the light so that the occupant of the moving body can visually recognize the image formed of the reflected image light as a virtual image. Yes.

  In the optical means, hereinafter, the image light incident side surface is defined as the incident side end surface, the image light output side surface is defined as the exit side end surface, and the cross section perpendicular to the specific direction intersects with the incident side end surface. The line is the incident side intersection line, and the intersection line with the emission side end face is the emission side intersection line.

  In the head-up display device, the image projection unit projects image light onto the reflection unit via the optical unit, and the light shielding unit enters the image unit from the non-projection surface side of the image light toward the optical unit. Block some of the outside light.

  Here, the optical means directs the outside light that has reached and reflected itself (the optical means) without being blocked by the light shielding means, outside the visual recognition area (the area that the occupant of the moving body visually recognizes, the so-called eye range). Thus, both the normal line at the incident side intersection line and the normal line at the emission side intersection line are arranged so as to be inclined with respect to the main optical axis of the image incident on the incident side end face. Note that the main optical axis of an image refers to a light axis passing through the center of the image projected by the image projection means.

  Therefore, according to the head-up display device of the present invention, out of the external light incident on the optical means from the non-projection surface side of the image in the reflective means, the external light that is reflected by the optical means and enters the eye range. The light blocking means must block the light. As a result, the head-up display device can project a display image with good visibility without being affected by external light.

By the way, as described in claim 2, the optical means preferably has a shape in which the incident-side intersection line and the emission-side intersection line are not parallel.
According to the head-up display device configured as described above, when the emission angles of the image light emitted from the emission side end surface are compared, the image emitted after undergoing reflection (multiple reflection) at the emission side end surface and the incident side end surface Since the light and the image light emitted without undergoing the multiple reflection are different, the former image light (the emitted light after the multiple reflection) may further direct the image light reflected by the reflecting means outside the viewing area. it can. That is, it is possible to prevent a ghost image made of image light that has undergone multiple reflections from being visually recognized by a vehicle occupant as a virtual image, and to project a display image with better visibility.

  Further, in the head-up display device configured as described above, assuming that the angle inclined with respect to the normal line of the main optical axis of the image incident on the optical means is the inclination angle, the emission side with respect to the inclination angle of the incident side end face Since the inclination angle of the end face can be made large, more external light reflected by the optical means is blocked by the light shielding means. For this reason, it is possible to more easily prevent external light from entering the eye range, and it is possible to set the lens installation depth to be relatively shallow, thereby further improving the mountability of the apparatus.

Further, as described in claim 3, the optical means is preferably arranged to be inclined with respect to an inclination axis (first inclination axis) along a specific direction.
Specifically, it is desirable that the optical means is set so that the specific direction is in the horizontal direction so that the image is affected by the optical action only in the horizontal direction. Note that “the combined direction” represents that the specific direction matches the horizontal direction, but does not necessarily require exact matching. For example, the angle between the specific direction and the horizontal direction may be within a range of about ± 20 °.

Alternatively, as described in claim 4, the optical means may be arranged such that the specific direction coincides with the horizontal direction of the video.
In the case where the optical means is arranged in this way, in the plane orthogonal to the horizontal direction, it is not affected by the optical action by the optical means, so that the external light reflected by the optical means is directed outside the viewing area. The inclination angle of the means can be obtained reliably.

  In the head-up display device of the present invention, the optical means may be constituted by, for example, a cylindrical lens as described in claim 5 or by a Fresnel lens as described in claim 6. May be.

In particular, in the latter case, the lens can be thinned, which can contribute to further downsizing of the apparatus.
Further, in the head-up display device of the present invention, the optical means is composed of a plurality of lenses made of materials having different refractive indexes and chromatic dispersions as described in claim 7, and the chromatic aberration is corrected in these lenses. In this case, the chromatic aberration caused by the optical action of the optical means can be corrected, so that a virtual image with good visibility can be obtained.

In the head-up display device of the present invention, it is desirable that the optical means has an optical action of enlarging the image as described in claim 8.
By disposing such optical means, the optical path of the image can be equivalently lengthened, which can contribute to downsizing of the apparatus.

  By the way, in the head-up display device of the present invention, as described in claim 9, one or a plurality of deflecting means for deflecting light are arranged on the path of the image light from the image projecting means to the optical means. It is desirable.

  In this case, since it is not necessary to make the irradiation direction from the image projection unit coincide with the optical axis direction of the optical unit, the degree of freedom of layout of the image projection unit is increased. Furthermore, when a plurality of deflecting means are arranged, the optical path of the image can be lengthened by effectively utilizing the limited space by bending a plurality of optical paths of the image, thereby further downsizing the apparatus. Can contribute.

  In the head-up display device of the present invention, it is desirable that at least one of the deflecting units gives an optical action to the light as described in claim 10. In the following, the deflection means that gives an optical action to light in this way is particularly called a deflection means with function.

When such a deflecting unit with a function is arranged, the optical action applied to the image by the optical unit is complemented, so that a virtual image with a good viewing state can be obtained.
Further, as described in claim 11, it is desirable that the optical action provided by at least one of the deflecting means with function is enlargement of an image.

In this case, a virtual image with a better viewing state can be obtained in order to complement the enlargement effect given to the image by the optical means.
Further, in the head-up display device of the present invention, at least one of the deflecting means with a function having an optical action is the main light of the image on the incident side end face (reflective surface) of the deflecting means as described in claim 12. It is arranged so that the normal line on the axis is inclined with respect to the main optical axis of the image incident on the deflecting means with function, and the inclination angle is a virtual image generated by the optical means being inclined. It is desirable that the angle is such as to cancel out the distortion.

  In this case, the distortion of the virtual image caused by the optical means having the optical action being inclined is offset by the distortion caused by the inclination of the functional deflecting means having the optical action being arranged. As a result, a good virtual image in a visible state with little distortion can be obtained.

  In the head-up display device of the present invention, as described in claim 13, one of the functional deflecting means is disposed in front of the optical means and is located in the same plane as the first tilt axis. It is desirable to incline around the second inclination axis. In addition, the state arrange | positioned in the front | former stage of an optical means means the state arrange | positioned so that the emitted light from a deflection means with a function may turn into the incident light of an optical means.

  In addition, it is desirable that the function-equipped deflecting unit is disposed so that an angle formed between the first tilt axis and the second tilt axis in the same plane is within a range of about ± 20 °. Further, as described in claim 14, it is further preferable that the first tilt axis and the second tilt axis are arranged in parallel.

  In this case, it is easy to set an inclination angle that cancels the distortion of the virtual image caused by the optical means being inclined, and the arrangement of the functional deflection means is facilitated. Furthermore, the installation space for the apparatus configuration is not wasted, and the apparatus can be downsized.

  Furthermore, in the head-up display device of the present invention, at least one of the deflecting means having an optical action is a distortion of a virtual image caused by the shape of at least one of the optical means and the reflecting means. It may have a shape that gives an optical action that cancels out.

In this case, it is only necessary to design the deflecting means in accordance with the optical action of the optical means or the reflecting means, and a virtual image with a better viewing state with less distortion can be obtained.
By the way, the head-up display device according to the present invention includes a housing that houses the image projection means, and the light shielding means also serves as an inner wall that forms an opening of the housing. The optical means may be arranged so that a part of the external light does not reach by the means.

In this case, since the light shielding means also serves as a part of the housing that houses the video projection means, the number of parts can be reduced. As a result, the manufacturing cost of the device can be reduced.
In the head-up display device of the present invention, as described in claim 17, the optical means may also serve as a cover that protects the inside of the housing.

  In this case, since the optical means also serves as a cover that protects the inside of the housing, the number of parts can be further reduced. As a result, the manufacturing cost of the device can be further reduced.

Embodiments of the present invention will be described below with reference to the drawings.
[First embodiment]
<Overall configuration>
FIG. 1 is a schematic configuration diagram showing a state in which a head-up display device (hereinafter referred to as a HUD device) of a first embodiment to which the present invention is applied is applied to a vehicle, and FIG. 2 is an enlarged view of a main part thereof. .

  As shown in FIG. 1, the HUD device 1 is disposed inside an instrument panel (hereinafter referred to as an instrument panel) 2 that extends from the lower edge of the front windshield 9 toward the vehicle interior side, and uses various information as video light 80. A display device 5 for projecting, a free-form curved mirror 6 for enlarging and reflecting the image light 80 projected from the display device 5, and a cylindrical lens 7 for enlarging and transmitting the image light 81 reflected by the free-form curved mirror 6. ing.

  The image light 82 that has passed through the cylindrical lens 7 is reflected by the front windshield 9 and reaches the eye range 3 of the vehicle occupant. As a result, the occupant visually recognizes that the virtual image of the image light 83 exists at the position of the display image 4 on the foreground of the vehicle (on the opposite side of the occupant across the front windshield 9).

  The instrument panel 2 has a cylindrical light guide 2 a that has an opening in the upper surface of the instrument panel 2 and guides the image light 81 reflected by the free-form curved mirror 6 to the front windshield 9. The cylindrical lens 7 is disposed so as to block the light guide portion 2a without a gap. That is, the cylindrical lens 7 also serves as a cover for dust-proofing the inside of the instrument panel 2 by closing the opening of the light guide portion 2a.

  However, the instrument panel 2 (including the inner wall that forms the light guide portion 2a) is formed of a light shielding resin. That is, the light incident on the upper surface of the instrument panel 2 and the inner wall forming the light guide 2a is configured to be absorbed without being reflected.

  In the following, the traveling direction of the main optical axis 8 of the image passing through the light guide portion 2a (transmitting through the cylindrical lens 7) is the Z direction, the vehicle width direction of the vehicle (the horizontal direction of the display image 4) is the X direction, the X direction, and A direction orthogonal to any of the Z directions is referred to as a Y direction.

  In addition, as shown in FIG. 2, a surface of the free-form surface mirror 6 that reflects the image light 80 projected from the display device 5 is referred to as a reflective surface 6 a, and is reflected by the reflective surface 6 a of the cylindrical lens 7. The surface on which the image light 81 is incident is referred to as the incident-side end surface 7a, and the surface from which the transmitted image light 82 is emitted is referred to as the transmission surface 7b.

<Configuration and action of cylindrical lens>
The cylindrical lens 7 is a well-known lens in which only one of the two directions orthogonal to the lens thickness direction (light transmitting direction) acts as a lens (focusing or diverging at a predetermined degree).

  3 is a perspective view of the cylindrical lens 7 as a single unit. As shown in the figure, in the following, the thickness direction of the lens is the γ direction, the direction acting as a lens (action axis direction) is the α direction, and the lens The direction that does not act as (the non-action axis direction) is referred to as the β direction.

  As shown in FIG. 3, the cylindrical lens 7 has a rectangular flat surface 70, one of the two surfaces located at both ends in the γ direction, and the other surface having a curved surface of a part of a cylinder. The formed lens forming surface 71 is formed. In addition, the cylindrical lens 7 has a shape in which a cross line with the flat surface 70 and a cross line with the lens forming surface 71 are parallel to each other in a cross section orthogonal to the α direction (that is, a cross section having a rectangular shape). Have.

  4A is an explanatory diagram showing the cross-sectional shape of the cylindrical lens 7 on the α-γ plane, and the traveling direction of light incident from the lens forming surface 71 along the γ direction, and FIG. FIG. 6 is an explanatory diagram showing a cross-sectional shape on the β-γ plane, a traveling direction of light incident from the lens forming surface 71 along the γ direction, and a traveling direction of the transmitted light.

  However, a vector representing the traveling direction of incident light at the central position in the α direction on the lens forming surface 71 is referred to as an incident vector Lc, and a vector representing the traveling direction of transmitted light based on the incident light is referred to as a transmission vector Tc. A vector representing the traveling direction of incident light at a position separated only in the α direction in the α-β plane from the center position in the α direction on the lens forming surface 71 is an incident vector Le, and the transmitted light travels based on the incident light. A vector representing the direction is referred to as a transmission vector Te.

  As shown in the figure, the cylindrical lens 7 has an optical action in the α direction with respect to incident light along the γ direction (directions of the transmission vectors Tc and Te are different in the α-γ plane). , Β has no optical effect (the directions of the transmission vectors Tc and Te are the same in the β-γ plane).

<Cylindrical lens arrangement>
As shown in FIGS. 5 and 6, the cylindrical lens 7 formed in this way has a lens forming surface 71 serving as an incident side end surface 7 a, a flat surface 70 serving as a transmitting surface 7 b, and an operation axis direction of the cylindrical lens 7 ( (α direction) coincides with the horizontal direction (X direction) of the display image 4, and the traveling direction (Z direction) of the main optical axis of the image light 81 with respect to the thickness direction (γ direction) of the cylindrical lens 7 and the Y direction with respect to the β direction. Is attached at a position of installation depth d from the opening of the light guide portion 2a in a so-called off-axis state inclined by an inclination angle θx.

  However, as shown in FIG. 6, the inclination angle θx and the installation depth d are determined when the incident angle of light incident on the transmission surface 7b of the cylindrical lens 7 (the angle with respect to the horizontal plane) is equal to or greater than the shielding upper limit incident angle θu. The light reflected by the transmission surface 7b of the cylindrical lens 7 is set so as not to reach the eye range 3 (see FIG. 6B), and external light incident at an incident angle equal to or smaller than the shielding upper limit incident angle θu is It is set so that it is blocked by the instrument panel 2 and cannot reach the cylindrical lens 7 (see FIG. 6A).

  Since the cylindrical lens 7 is arranged with the action axis direction (α direction) coincided with the X direction so as to have an optical action only in the X direction, the cylindrical lens 7 of the cylindrical lens 7 is arranged in the YZ plane. The reflection direction of the external light incident on the transmission surface 7b can be uniquely specified.

  Further, the shielding upper limit incident angle θu, and hence the installation depth d and the inclination angle θx are appropriately set for each vehicle type based on the shape of the front windshield 9 and the formation position and orientation of the light guide portion 2a.

<Influence of off-axis>
Here, FIG. 7 is an explanatory diagram showing the influence of the cylindrical lens 7 being attached off-axis.

  7A is a perspective view of the cylindrical lens 7 attached to the light guide 2a as viewed from the Y direction, and FIG. 7B is a side view of the cylindrical lens 7 as viewed from the X direction. It is.

  As described above, in the cylindrical lens 7 arranged so that the γ direction (thickness direction of the cylindrical lens 7) is inclined with respect to the Z direction (traveling direction of the main optical axis 8), as shown in FIG. In addition, when viewed in the XZ plane, of the image light 81 incident along the Z direction, the image with respect to the incident vector Lc of the image light 81c incident at the center position in the X direction (= α direction). The transmission vector Tc of the light 81c has the same direction, and the transmission vector Te of the image light 81e is at an angle with respect to the incident vector Le of the image light 81e incident at a distance Xe from the center position in the X direction. It will have. That is, the cylindrical lens 7 exerts an optical action (enlargement in the present embodiment) on incident light whose incident position is different in the X direction.

  In addition, as shown in FIG. 7B, this cylindrical lens 7 is viewed in the YZ plane, and among the video light 81 incident along the Z direction, the cylindrical lens 7 extends in the Y direction within the same XY plane. The transmission vectors Tc and Td of the image lights 81c and 81d that are incident only at positions separated from each other are directed in the same direction. That is, the cylindrical lens 7 does not exert an optical action on incident light whose incident position is different in the Y direction.

  However, even if the incident positions in the Y direction are the same in the YZ plane, the transmission vectors Tc and Te of the image lights 81c and 81e having different incident positions in the X direction are directed in different directions. In addition, the deviation in the direction becomes larger as the position deviates from the center position in the X direction with reference to the directions of the transmission vectors Tc and Td of the image light 81c and 81d incident on the center position in the X direction (that is, the Z direction).

  This is because if the incident position is different in the X direction, the three-dimensional direction of the normal vector at the incident position is different, and the influence appears in the direction of the transmission vector in the YZ plane. is there.

  Specifically, assuming that the normal vector at the incident position of the image light 81c on the incident side end surface 71 of the cylindrical lens 7 is Nc, and the normal vector at the incident position of the image light 81e is Ne, these normal vectors Nc, When an angle formed by Ne on the XZ plane is an angle φx, the vector components of the normal vectors Nc and Ne can be expressed as shown in (2), respectively. However, since the incident vector Lc and the incident vector Le are both equal, the incident vectors Lc and Le are represented by the same unit vector here.

The transmission vector T of the image light 82 that has passed through the cylindrical lens 7 is represented by L as the incident vector of the image light 81 incident on the cylindrical lens 7 and N as the normal vector at the incident position of the image light 81 on the incident side end face 71. When the refractive index of the cylindrical lens 7 is η, the relationship shown in the equation (3) is established.

Therefore, the transmission vectors Tc and Te can be obtained by substituting the vector components of the incident vectors Lc and Le in (2) and the normal vectors Nc and Ne into the equation (3), respectively.

  That is, as is clear from the equations (2) and (3), the transmission vector Te indicating the direction of the image light 82e through which the image light 81e incident on the position away from the center position in the X direction passes through the lens is The vector components in the Y and Z directions are affected by the angle φx. For this reason, between the transmission vector Tc indicating the traveling direction of the image light 82c through which the image light 81c incident on the center position in the X direction (= α direction) passes through the lens, and the transmission vector Te, YZ A deviation on the plane (that is, a deviation of the emission angle) occurs.

  Due to this shift, as shown in FIG. 8A, the display light 4 c based on the video light 83 c reflected by the front windshield 9 and the video light 83 e reflected by the front windshield 9 are reflected on the display image 4 c. The position of the displayed display image 4e is also shifted in the vertical direction (downward in the figure), and the shift becomes larger as the both ends in the horizontal direction (away from the center position in the X direction).

Therefore, the cylindrical lens 7 arranged in an off-axis state causes a fan-shaped distortion as shown in FIG. 8B in the display image 4 visually recognized by the vehicle occupant.
FIG. 8 does not show the action actually obtained by the HUD device 1 but shows the action when the image light is directly projected from the display device 5 to the cylindrical lens 7 without passing through the free-form surface mirror 6. It is explanatory drawing.

<Configuration and operation of free-form surface mirror>
Next, as shown in FIG. 9A, the free-form surface mirror 6 has a reflection surface 6a that reflects light, and the optical axis direction of the free-form surface mirror 6 is the γ direction, and two directions orthogonal to the γ direction. Is the α direction and β direction, the coordinate in the γ direction is γ, the coordinate in the α-β plane is (α, β), and the shape of the reflection surface 6a is expressed by the polynomial γ = f (α, β). It is a well-known one consisting of a curved surface (see FIG. 11).

  The curved surface of the reflecting surface 6a has such a curvature that the incident light is expanded in the α direction and the β direction, and an optical action for correcting the distortion of the display image 4 generated based on the shape of the front windshield 9 is obtained. Is set.

  Here, FIG. 10A is an explanatory diagram showing the cross-sectional shape of the free-form surface mirror 6 in the α-γ plane and the traveling direction of the light reflected by the reflecting surface 6a viewed from the β direction, FIG. 10B. These are explanatory drawings showing the cross-sectional shape of the free-form surface mirror 6 on the β-γ plane and the traveling direction of the light reflected by the reflecting surface 6a viewed from the α direction.

  In the following, a vector representing the traveling direction of incident light at the center position in the α direction and β direction on the reflecting surface 6a of the free-form curved mirror is an incident vector Lc, and a vector representing the traveling direction of the reflected light based on the incident light. Is referred to as a reflection vector Rc, and a vector representing the traveling direction of the incident light at a position away from the center position in the α-direction and β-direction in the α-direction in the α-β plane is defined as the incident vector Le. A vector representing the traveling direction of the reflected light based on this is called a reflection vector Re.

  That is, the free-form surface mirror 6 exerts an optical action on the incident light along the γ direction in both the α direction and the β direction (in both the α-γ plane and the β-γ plane, the reflection vector). As shown in the figure, the reflected light (reflected vectors Rc, Re) of the incident light at the center position in the β direction in the α-β plane reflected by the reflecting surface 6a is When viewed in the β-γ plane, they face in the same direction.

<Arrangement of free-form curved mirror>
In the free-form surface mirror 6 formed in this way, as shown in FIG. 12, the α direction coincides with the X direction (the horizontal direction of the display image 4), and the Z direction with respect to the γ direction (the Y direction with respect to the β direction is also (Same) is tilted by the tilt angle θm, so-called off-axis, and the light reflected at the center of the free-form surface mirror 6 is disposed at a position where it passes through the center of the cylindrical lens 7.

<Influence of off-axis>
Here, FIG. 13 is explanatory drawing which shows the influence by the free-form surface mirror 6 being attached in the state off-axis. However, as illustrated, in the following, the traveling direction of the main optical axis 8 of the image projected from the display device 5 is the z direction, and the horizontal direction of the image is orthogonal to the x direction, the z direction, and the x direction. The direction to do is called the y direction.

  13A is a perspective view of the free-form surface mirror 6 attached to the HUD device 1 as viewed from the y-axis direction, and FIG. 13B is the same view of the free-form surface mirror 6 in the x-axis direction (= It is the side view seen from (X-axis direction).

  As described above, in the free-form curved mirror 6 arranged so that the γ direction is inclined with respect to the Z direction (the γ direction is also inclined with respect to the z direction), as shown in FIG. When viewed in the z plane, out of the image light 80 incident along the z direction, the image light 80c and 80e incident at positions separated only in the x direction within the same xy plane are the methods at the incident position. The line vectors Nc and Ne are different from each other.

  For this reason, as shown in FIG. 13B, when viewed in the yz plane, the reflection vectors Re and Rc of the image lights 80c and 80e are affected by the different normal vectors Nc and Ne, They will face in different directions.

  Specifically, when the angle formed by the normal vectors Nc and Ne in the xz plane is an angle φm, the vector components of the normal vectors Nc and Ne can be expressed as shown in (4). However, since the incident vector Lc and the incident vector Le are both equal, the incident vectors Lc and Le are represented by the same unit vector here.

The reflection vector R indicating the traveling direction of the image light 81 reflected by the free-form curved mirror 6 is L, which is an incident vector indicating the traveling direction of the image light 80 incident on the free-form curved mirror 6, and the image light 80 on the reflecting surface 6a. When the normal vector representing the normal direction at the incident position is N, the relationship shown in the equation (5) is established.

Therefore, the reflection vectors Rc and Re can be obtained by substituting the vector components of the incident vectors Lc and Le in (4) and the normal vectors Nc and Ne into the equation (5), respectively.

  That is, as apparent from the equation (5), the reflection vector Re indicating the traveling direction of the image light 81e reflected by the image light 80e incident on the position deviated from the center position in the x direction is expressed in the y direction and the z direction. The vector component is affected by the angle φm. For this reason, there is a deviation on the yz plane between the reflection vector Rc indicating the traveling direction of the image light 81c reflected by the image light 80c incident on the center position in the x direction and the reflection direction vector Re ( That is, a reflection angle shift) occurs.

  Due to this shift, as shown in FIG. 14A, the display light 4c based on the video light 83c reflected by the front windshield 9 and the video light 83e reflected by the front windshield 9 are reflected in the display image 4c. The position of the displayed display image 4e is also shifted in the vertical direction (upward in the figure), and the shift becomes larger as the both ends in the horizontal direction (away from the center position in the x direction).

Therefore, the free-form surface mirror 6 arranged in an off-axis state causes a reverse fan-shaped distortion as shown in FIG. 14B in the display image 4 visually recognized by a vehicle occupant.
Note that FIG. 14 does not show the action actually obtained by the HUD device 1, and the image light projected from the display device 5 is reflected by the free-form surface mirror 6, and does not pass through the cylindrical lens 7. It is explanatory drawing which shows an effect | action at the time of projecting image light directly on the windshield 9. FIG.

  In other words, image lights having different incident positions in the X direction are reflected by the free-form surface mirror 6 to cause a positional shift in the Y direction in the YZ plane by ΔM, and transmitted through the cylindrical lens 7 as YZ. The inclination angle θm of the free-form curved mirror 6 cancels out the distortion of the display image 4 caused by the free-form curved mirror 6 and the distortion of the display image 4 caused by the cylindrical lens 7 with the positional deviation in the Y direction occurring in the plane being ΔL. As described above, ΔM is set to have the same size as ΔL, and the direction of deviation in the Y direction is set to be opposite.

  In the above embodiment, the front windshield 9 corresponds to reflecting means, the cylindrical lens 7 corresponds to optical means, the display device 5 corresponds to video projection means, the instrument panel 2 corresponds to shielding means, and the free-form surface mirror 6 corresponds to deflection means.

<Effect of the first embodiment>
As described above, in the HUD device 1 of the present embodiment, when the inclination angle θx and the installation depth d of the cylindrical lens 7 are equal to or greater than the shielding upper limit incident angle θu, the incident angle of light incident on the transmission surface 7b In addition, the light reflected by the transmission surface 7 b is set so as not to reach the eye range 3, and outside light incident at an incident angle equal to or smaller than the shielding upper limit incident angle θu is blocked by the instrument panel 2 and reaches the cylindrical lens 7. The cylindrical lens 7 is attached in the light guide part 2a so that it becomes impossible.

Therefore, according to the HUD device 1, since the external light reflected by the cylindrical lens 7 does not enter the occupant's eye range 3, a display image 4 with high visibility can be obtained.
Further, in the HUD device 1, distortion of the display image 4 (fan-shaped distortion) due to the cylindrical lens 7 being arranged at an inclination and display image 4 due to the arrangement of the free-form curved mirror 6 at an inclination. Are arranged so as to cancel out the distortion (reverse fan-shaped distortion). In other words, the balance between the magnification and the tilt angle of the cylindrical lens 7 and the magnification and the tilt angle of the free-form surface mirror 6 can cancel the distortion, and the display image 4 without distortion can be occupant with a simple configuration. It can be visually recognized.

<Modification of the first embodiment>
In the above embodiment, the cylindrical lens 7 is used as the optical means. Instead of the cylindrical lens 7, a linear Fresnel lens 700 having an optical action only in one direction as shown in FIG. 15 is used. Also good.

In this case, as is apparent from the drawing, the linear Fresnel lens 700 has a smaller thickness than the cylindrical lens 7, and thus can contribute to downsizing of the HUD device 1.
Further, instead of the cylindrical lens 7, as shown in FIG. 16, the substrate itself is a concave surface 711 having the shape of the inner surface of the cylinder after having a curvature for enlarging the incident light in the α direction. A curved substrate-like cylindrical lens 710 whose surface is a convex surface 712 along the concave surface 711 may be used. Further, a curved substrate-like linear Fresnel lens as shown in FIG. 17 may be used.

  In this way, by making the lens substrate a cylindrical curved substrate, the light shielding upper limit angle θu becomes small as shown in FIG. 18A, and the light shielding upper limit as shown in FIG. 18B. It becomes easy to deflect outside light incident at an angle θu or more to the outside of the eye range, and as a result, the light shielding portion of the instrument panel 2 can be lowered. That is, since the mounting position (that is, the installation depth d) can be reduced, the mounting property in the instrument panel can be improved.

  In addition, an achromatic lens, an achromatic lens, an apochromatic lens, or the like configured by combining a plurality of lenses made of materials having different refractive indexes and chromatic dispersions so as to correct chromatic aberration may be used.

In this case, the display image 4 with very small chromatic aberration can be obtained, and the visibility of the display image 4 can be further improved.
Instead of the cylindrical lens 7, a free-form surface lens having an optical action not only in the α direction but also in the β direction may be used. However, the optical action in the β direction is so small that the external light reflected by the transmission surface 7b can be controlled not to enter the eye range 3 by appropriately setting the inclination angle θx and the installation depth d. There must be.

In this case, for example, a distortion based on the shape of the front windshield 9 may be corrected not by the free-form surface mirror 6 but by this free-form surface lens.
In the above embodiment, the cylindrical lens 7 is arranged with the α direction coincident with the X direction. However, as shown in FIG. 19, the α direction may be arranged with an inclination angle θy inclined with respect to the X direction. Good. However, since the influence of the optical action in the α direction also appears in the YZ plane due to this inclination, the inclination angle θy is reflected by the transmission surface 7b even if it is affected by the optical action. It is necessary to set within a range where outside light does not enter the eye range 3.

In this case, the correction of the distortion of the display image 4 in the horizontal direction can be finely adjusted, and the visibility of the display image 4 can be improved.
In the above embodiment, only one free-form surface mirror 6 is used as the deflecting means. However, as shown in FIG. 20, the image light 8b reflected by the free-form surface mirror 6 is further reflected to form a cylindrical lens 7. You may add the reflecting mirror 66 which guides to.

  In this case, since the same space is used redundantly as the path of the image light, the path of the image light can be lengthened even in the limited space inside the instrument panel 2, and the HUD device can be further increased. 1 can be reduced in size.

The number of reflecting mirrors 66 is not limited to one, and two or more reflecting mirrors 66 may be provided. The reflecting mirror 66 may have an optical action such as enlargement.
Moreover, in the said Example, although the free-form surface mirror 6 is installed in the direction where the cylindrical lens 7 and the display device 5 are arrange | positioned on the same YZ plane (position of the X direction is the same), The free-form surface mirror 6 may be installed in such an orientation that they are arranged on different YZ planes (that is, positions in the X direction are different) according to the space shape in the instrument panel 2.

That is, the degree of freedom of arrangement of the device configuration can be improved by appropriately setting the direction of the free-form curved mirror 6.
Further, in the above-described embodiment, the distortion caused by the cylindrical lens 7 being arranged off-axis is corrected by inclining the free-form surface mirror 6 so as to produce a distortion that cancels out the distortion. You may comprise so that it may correct | amend by the curved surface shape of the free-form surface lens arrange | positioned instead of the mirror 6 or the cylindrical lens 7. FIG.

[Second Embodiment]
Next, a second embodiment will be described.
FIG. 25 is a perspective view and a cross-sectional view showing the shape of the wedge-shaped cylindrical lens 730.

  The head-up display device (HUD device) 1 of this embodiment is different from the device of the first embodiment only in that the cylindrical lens 7 is replaced with a wedge-shaped cylindrical lens 730. Therefore, this difference is mainly described. To do.

<Configuration and operation of wedge-shaped cylindrical lens>
As shown in FIG. 25, the wedge-shaped cylindrical lens 730 has an intersecting line (hereinafter referred to as an exit-side intersecting line) with the transmitting surface 7b (731) among the surfaces (cross section) orthogonal to the action axis direction (α direction). The lens has a shape that is non-parallel to an intersection line (hereinafter referred to as an incident-side intersection line) with the incident-side end surface 7a (732), that is, a shape having a wedge-shaped cross section.

  FIG. 25 (a) is a perspective view of the wedge-shaped cylindrical lens 730 alone. As shown in the drawing, in the following description, the operating axis corresponds to the cylindrical lens 7 (see FIG. 3) of the first embodiment. The direction is referred to as the α direction, the non-action axis direction as the β direction, and the thickness direction as the γ direction. In other words, the wedge-shaped cylindrical lens 730 has a shape in which one of the two surfaces located at both ends in the γ direction is a rectangular flat surface 731 and the other surface approximates a curved surface of a part of a cylinder. The lens forming surface 732 is formed.

  FIG. 25B is an explanatory diagram showing a cross-sectional shape of the wedge-shaped cylindrical lens 730 in the β-γ plane. As shown in the figure, the wedge-shaped cylindrical lens 730 has an exit-side intersection line on the incident-side intersection. It is formed so as to be inclined by a wedge angle θw (for example, θw = 2 °) defined in advance with respect to the line. However, the wedge angle θw is set in such a range that the influence of the chromatic aberration due to the prism effect does not appear in the display image 4 when the wedge-shaped cylindrical lens 730 is incorporated in the HUD device 1.

Next, FIG. 26 is a schematic view showing a state in which a wedge-shaped cylindrical lens 730 is attached in the light guide portion 2a instead of the cylindrical lens 7 of the first embodiment.
As shown in FIG. 26, the wedge-shaped cylindrical lens 730 is arranged in such a direction that the transmission surface 731 faces the front side of the vehicle and the thickness of the lens increases toward the rear side of the vehicle.

  In the HUD device 1 in which the wedge-shaped cylindrical lens 730 is arranged in this manner, among the image light 81 incident on the incident-side end surface 732, the light 82 that is emitted from the transmission surface 731 without being reflected inside the lens is front windshield. 9 is reflected to reach the eye range 3. On the other hand, the light (ghost light) 802 emitted from the transmission surface 731 after being reflected by the transmission surface 731 and the incident-side end surface 732 (that is, multiple reflection inside the lens) is not reflected inside the lens and is transmitted through the transmission surface. Since the light is directed toward the rear side of the vehicle as compared with the light 82 that is emitted from 731, the light is directed toward the upper outside of the eye range 3 when reflected by the front windshield 9.

<Effect of the second embodiment>
Therefore, according to the HUD device 1 of the present embodiment, it is possible to prevent the ghost image made of ghost light from being visually recognized by the occupant as a virtual image, and to reliably project the display image 4 with high visibility. it can.

  Furthermore, in the wedge-shaped cylindrical lens 730 attached in the light guide portion 2a, since the tilt angle of the transmission surface 731 is larger than the tilt angle of the incident-side end surface 732, the external light reflected by the wedge-shaped cylindrical lens 730 is It will be blocked by the instrument panel 2 (vehicle front side) more.

  Therefore, according to the HUD device 1 of the present embodiment, it is possible to more easily prevent external light from entering the eye range 3 and to set the installation depth d of the wedge-shaped cylindrical lens 730 to be relatively shallow. Further, the mountability of the apparatus can be further improved.

<Modification of Second Embodiment>
In the above embodiment, the wedge-shaped cylindrical lens 730 is used instead of the cylindrical lens 7, but the present invention is not limited to this, and another lens having a wedge-shaped cross section may be used. For example, as shown in FIG. 27, of the surface (cross section) orthogonal to the non-operation axis direction (β direction), the exit side intersection line is non-parallel to the incident side intersection line, A wedge-shaped Fresnel lens 740 that can realize a function equivalent to the wedge-shaped cylindrical lens 730 may be used instead of the cylindrical lens 7.

  Further, the wedge-shaped cylindrical lens 730 of the above-described embodiment is disposed such that the transmission surface 731 faces the front side of the vehicle and the thickness of the lens increases toward the rear side of the vehicle. As shown in FIG. 28, the transmission surface 731 may face the rear side of the vehicle, and the lens thickness may increase in the direction toward the front side of the vehicle. In this case, the ghost light 802 that is emitted from the transmission surface 731 after being subjected to multiple reflections inside the lens is directed more toward the front side of the vehicle than the light 82 that is emitted from the transmission surface 731 without being reflected inside the lens. Therefore, the light is reflected by the front windshield 9 and is directed to the lower outside of the eye range 3.

BRIEF DESCRIPTION OF THE DRAWINGS The schematic block diagram which shows the state by which the head-up display apparatus of this invention (1st Example) was applied to the vehicle. The enlarged view which shows the principal part of schematic structure which shows the state by which the head-up display apparatus of this invention (1st Example) was applied to the vehicle. The perspective view of a cylindrical lens. Explanatory drawing which shows the progress of the light which injects into the cross-sectional shape of a cylindrical lens, and the said cylindrical lens. FIG. 3 is a first explanatory view showing a tilted state of a cylindrical lens. Explanatory drawing which shows the arrangement | positioning state of a cylindrical lens. The 1st explanatory view which shows the influence by having attached the cylindrical lens in the state of off-axis. The 2nd explanatory view which shows the influence by having attached the cylindrical lens in the state of off-axis. The perspective view of a free-form surface mirror. Explanatory drawing which shows the progress of the light which injects into the cross-sectional shape of a free-form surface mirror, and the said free-form surface mirror. Explanatory drawing expressing the reflective surface of a free-form surface mirror. Explanatory drawing which shows the inclination state and arrangement | positioning state of a free-form surface mirror. 1st explanatory drawing which shows the influence by having attached a free-form surface mirror in the state off-axis. The 2nd explanatory view which shows the influence by having attached the free-form surface mirror in the state of off-axis. The perspective view of a linear Fresnel lens. The perspective view of a curved substrate-like cylindrical lens. The perspective view of a curved substrate-like linear Fresnel lens. Explanatory drawing which shows the arrangement | positioning state of a curved substrate-like cylindrical lens (or curved substrate-like linear Fresnel lens). The 2nd explanatory view showing the state of inclination of a cylindrical lens. Explanatory drawing which shows the arrangement | positioning state of a some free-form surface mirror. Explanatory drawing which shows the principle which can lengthen an optical path equivalently with a general convex lens as an expansion lens. Explanatory drawing which shows that a virtual image appears in the position which permeate | transmitted the front windshield. Explanatory drawing which shows a mode that the sunlight reflected on the lens enters into a passenger | crew's eye range. A photograph showing noise caused by sunlight appearing in the display image. The perspective view and sectional drawing of a wedge-shaped cylindrical lens. The 1st explanatory view showing the arrangement state of a wedge-shaped cylindrical lens. The perspective view and sectional drawing of a wedge-shaped Fresnel lens. The 2nd explanatory view showing the arrangement state of a wedge-shaped cylindrical lens.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... HUD apparatus, 2 ... Instrument panel, 3 ... Eye range, 4 ... Display image, 5 ... Display device, 6 ... Free-form mirror, 7 ... Cylindrical lens, 8 ... Main optical axis, 9 ... Front windshield.

Claims (17)

A head-up display device that is mounted on a moving body provided with a reflecting means that transmits and reflects light, and that causes an image of the image light reflected by the reflecting means to be visually recognized by a passenger of the moving body as a virtual image,
An optical means for giving an optical action to light in a specific direction set in advance and transmitting the light;
Image projection means for projecting image light to the reflection means via the optical means;
A light shielding means for blocking a part of the external light incident toward the optical means from the non-projection surface side of the image light in the reflecting means;
With
In the optical means, the incident-side and emission-side surfaces of the video light are defined as an incident-side end surface and an emission-side end surface, and a crossing line with the incident-side end surface of the cross section orthogonal to the specific direction is defined as an incident-side intersection line; The intersection line with the emission side end face is defined as the emission side intersection line.
The outside light that reaches the optical means without being shielded by the light shielding means and is reflected by the optical means is directed outside the visual recognition area, which is an area in which the occupant of the moving body visually recognizes the video. The optical means is arranged such that a normal line at the incident side intersection line and a normal line at the emission side intersection line are both inclined with respect to the main optical axis of the image incident on the incident side end face. A head-up display device.   2. The head-up display device according to claim 1, wherein the optical unit has a shape in which the incident-side intersection line and the emission-side intersection line are not parallel to each other.   3. The head-up display device according to claim 1, wherein the optical unit is arranged to be inclined with respect to a first inclination axis along the specific direction.   The head-up display device according to claim 3, wherein the specific direction is a horizontal direction of the video.   The head-up display device according to claim 3, wherein the optical unit includes a cylindrical lens.   The head-up display device according to claim 2, wherein the optical unit includes a Fresnel lens.   7. The optical means comprises a plurality of lenses made of materials having different refractive indexes and chromatic dispersions, and the plurality of lenses are combined so that chromatic aberration is corrected. A head-up display device according to any one of the above.   8. The head-up display device according to claim 1, wherein the optical action provided by the optical means is enlargement of an image. Comprising one or more deflecting means for deflecting light;
9. The head-up display device according to claim 1, wherein the deflecting unit is disposed on a path of the image light from the image projecting unit to the optical unit.   The head-up display device according to claim 9, wherein at least one of the deflecting units includes a deflecting unit with a function for applying an optical action to light.   11. The head-up display device according to claim 10, wherein the optical action provided by the functional deflection unit is an enlargement of an image.   At least one of the functional deflecting means is configured such that a normal line on the main optical axis of the image on the incident side end face of the functional deflecting means is inclined with respect to the main optical axis of the video incident on the functional deflecting means. The tilt angle is an angle that cancels out the distortion of the virtual image caused by the tilting of the optical means. 11. The head-up display device according to 11.   One of the function-deflecting means is arranged in front of the optical means and is inclined with respect to a second inclination axis located in the same plane as the first inclination axis along the specific direction. The head-up display device according to claim 12, wherein   14. The head-up display device according to claim 13, wherein the optical unit and the deflecting unit with a function are arranged so that the first tilt axis and the second tilt axis are parallel to each other. .   10. At least one of the deflecting means has a shape that provides an optical action that cancels out distortion of the virtual image caused by the shape of at least one of the optical means and the reflecting means. Item 15. The head-up display device according to any one of Items 14. Provided with a housing having an opening with the video projection means inside,
16. The optical device according to any one of claims 1 to 15, wherein the optical means is arranged so that a part of outside light does not reach by a light shielding means that also serves as an inner wall forming an opening of the casing. The head-up display device described in 1.   The head-up display device according to claim 16, wherein the optical unit also serves as a cover for dust-proofing the inside of the housing.