Head-up display device

A head-up display device which can be applied to various types of vehicles is provided without causing cost increase. A head-up display device which makes a virtual image to be formed by projecting display light on a windshield of a vehicle includes a housing, an indicator which is provided in the housing, and a reflector which is provided in the housing, and includes a plurality of reflecting surfaces which are arranged in parallel with each other and inclined at the same angle so that the display light which is irradiated from the indicator is reflected by the reflecting surfaces.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention relates to a head-up display device which projects a virtual image on a projection area of a windshield of a vehicle so that the projected virtual image is superimposed on a foreground of the vehicle, which is visually recognized from an eye point of the vehicle through the windshield, and visually recognized.

2. Background Art

In recent years, with the increase and diversification of information required when a driver is driving, a head-up display (HUD) device which causes urgent information or the like to be displayed as a virtual image on a windshield of a vehicle, and causes the virtual image to be superimposed on a foreground of the vehicle, which is visually recognized through the windshield, and visually recognized, is mounted on the vehicle, such as a car or a train.

In this kind of head-up display device, an image displayed on a display panel is reflected and enlarged by a flat mirror and a concave mirror, and the enlarged image is irradiated and reflected to a display area of the windshield of a car so that a virtual image of the image is visually recognized by the driver of the car (for example, refer to JP-A-2009-222881).

SUMMARY OF THE INVENTION

In the above-mentioned head-up display device, by providing a flat mirror in a housing and returning an optical path halfway with the flat mirror, the housing is downsized.

Since the inclination of the windshield on which a virtual image is projected varies for each of various types of vehicles, when the same head-up display device is mounted, a displacement in position where the virtual image is formed occurs for each type of vehicle.

Therefore, in order to offset the displacement in position where the virtual image is formed in a different type of vehicle, it is necessary to correct the displacement by changing the angle of the flat mirror, or changing the position of an indicator which irradiates display light.

However, when the angle change of the flat mirror or the position change of the indicator is performed in this way, the structure or shape of an attaching part of the flat mirror or the indicator must be changed, and as a result, a different housing has to be prepared for each of various types of vehicles, which becomes a factor of cost increase.

The present invention is made in view of the situation mentioned above, and an object of the present invention is to provide a head-up display device which can be applied to various types of vehicle without causing cost increase.

In order to achieve the object mentioned above, the present invention may be implemented by any one of the following (1) to (5).

(1) A head-up display device which makes a virtual image to be formed by projecting display light on a windshield of a vehicle, the head-up display device including:

a housing;

an indicator which is provided in the housing; and

a reflector which is provided in the housing, and includes a plurality of reflecting surfaces which are arranged in parallel with each other and inclined at the same angle so that a display light which is irradiated from the indicator is reflected by the reflecting surfaces.

(2) The head-up display device according to the configuration (1), wherein

the reflector includes a linear Fresnel lens in which a plurality of slopes which are arranged in parallel with each other and inclined at the same angle are formed, and the slopes become the reflecting surfaces by being mirrored.

(3) The head-up display device according to the configuration (2), wherein

the reflector is configured so that front surfaces of the slopes of the linear Fresnel lens which are mirrored become the reflecting surfaces, and the display light is reflected by the reflecting surfaces which include the front surfaces of the slopes.

(4) The head-up display device according to the configuration (2), wherein

the reflector is configured so that back surfaces opposite to front surfaces of the slopes of the linear Fresnel lens which are mirrored become the reflecting surfaces, and the display light which enters from the back surfaces of the linear Fresnel lens is reflected by the reflecting surfaces which include the back surfaces of the slopes.

(5) The head-up display device according to the configuration (4), wherein

the back surface of the linear Fresnel lens is inclined relative to a processed surface which is formed with the slopes.

In the head-up display device of the configuration (1), by incorporating the reflector which has reflecting surfaces of a suitable inclined angle corresponding to the inclination of the windshield which is mounted on the vehicle, it can be very easy to cause the head-up display device to be suited for the vehicle with device.

Therefore, it is unnecessary to correct by changing the angle of a flat mirror according to the type of a vehicle, or changing the position of the indicator which irradiates an image as when the flat mirror is used as the reflector, and thus the cost increase due to the fact that a different housing is prepared for each of various types of vehicles can be avoided.

In the head-up display device of the configuration (2), the display light from the indicator can be reflected towards a suitable direction by the reflecting surfaces which are formed of the slopes of the linear Fresnel lens in which the plurality of slopes which are arranged in parallel with each other and inclined at the same angle are formed.

In the head-up display device of the configuration (3), the display light from the indicator can be reflected towards a suitable direction by the reflecting surfaces which are formed of the front surfaces of the slopes of the linear Fresnel lens which are mirrored.

In the head-up display device of the configuration (4), the display light from the indicator which enters from the back surface of the linear Fresnel lens can be reflected towards a suitable direction by the reflecting surfaces which are formed of the back surfaces opposite to the front surfaces of the slopes of the linear Fresnel lens which are mirrored.

Since the valleys of the linear Fresnel lens, which are easy to be formed to have an acute angle when the processed surface is molded with a metal mold, become peaks when viewed from the side of the back surface, the display light can be prevented from being diffusely reflected at the peaks, and thus it can be avoided that the virtual image becomes hazy due to the occurrence of flare.

In the head-up display device of the configuration (5), since the back surface is inclined to the processed surface in which the slopes of the linear Fresnel lens are formed, the reflected light of the display light reflected with the back surface of the linear Fresnel lens is led towards a direction greatly different from that of the display light which is reflected by the reflecting surfaces, and will not reach the projection area of the windshield. Therefore, the trouble that the virtual image becomes hazy due to the reflected light by the back surface of the linear Fresnel lens can be avoided.

In order to achieve the object mentioned above, the present invention may be implemented by the following (6).

(6) A head-up display device which makes a virtual image to be formed by projecting display light on a windshield of a vehicle, the head-up display device including:

a housing;

an indicator which is provided in the housing; and

a reflector which is provided in the housing, and includes a non-regular-reflection type holographic mirror which makes light that is irradiated from the indicator to be reflected at a reflection angle different from an incidence angle.

In the head-up display device of the configuration (6), by incorporating the reflector including the non-regular-reflection type holographic mirror of a suitable reflection angle corresponding to the inclination of the windshield which is mounted on the vehicle, it can be very easy to cause the head-up display device to be suited for the vehicle with device.

Therefore, it is unnecessary to correct by changing the angle of a flat mirror according to the type of a vehicle, or changing the position of the indicator which irradiates an image as when the flat mirror is used as the reflector, and thus the cost increase due to the fact that a different housing is prepared for each of various types of vehicles can be avoided.

According to the present invention, a head-up display device which can be applied to various types of vehicle can be provided without causing cost increase.

The invention is explained in brief above. Further, details of the invention will become more apparent after the embodiments of the invention described below are read with reference to the accompanying figures.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

First Embodiment

First, a head-up display device according to the first embodiment is described.

As shown inFIG. 1, a head-up display (HUD) device11is used after being installed in an instrument panel or on the instrument panel below a windshield (windshield glass)12.

The head-up display device11projects display light L on a projection area E of the windshield12, and forms a virtual image of display information on the projection area E so that the virtual image is superimposed on a foreground of a vehicle, which is visually recognized through the windshield12, and visually recognized by a driver from the eye point (eye point) EP of the driver.

As shown inFIG. 2, the head-up display device11has a housing21which is provided below the windshield12of the vehicle, and an indicator22which irradiates the display light L is provided in the housing21. A spontaneous optical device (for example, a field emission display, a fluorescent display tube, an electroluminescence display, or the like), a liquid crystal display with a backlight, or the like is used as the indicator22.

A reflector23which reflects the display light L irradiated from the indicator22is provided in the housing21, and the display light L reflected by the reflector23is enlarged by an enlargement mirror24and led to the windshield12. The reflector23is fixed to a predetermined position in the housing21, and is removable from the housing21. Since the display light L irradiated from the indicator22is reflected and refracted by the reflector23so that the direction of the display light L is changed, the housing21of the head-up display device11is downsized.

As shown inFIGS. 3 and 4, the reflector23has a plurality of reflecting surfaces31which are arranged in parallel with each other and inclined at the same angle, and the display light L irradiated from the indicator22is reflected respectively by the reflecting surfaces31.

The reflector23includes a linear Fresnel lens34, which is formed of a plurality of slopes32, which are arranged in parallel with each other and inclined at the same angle, and vertical surfaces33which are the boundaries of adjoining slopes32. A mirror finishing is performed on a processed surface34a, which is formed with the slopes32and the vertical surfaces33of the linear Fresnel lens34, with aluminum vapor deposition, and thereby the front surfaces of the slopes32of the linear Fresnel lens34become the reflecting surfaces31, respectively.

The linear Fresnel lens34is formed of a light transmitting material, and for example, is formed by injection molding transparent resin. For example, the light transmitting material may be a plastics base material. Thermoplastics resin, thermosetting resin, or resins which can be hardened by energy rays such as ultraviolet rays or electron beams, may be used as the plastics. Specifically, for example, polyolefin resin, such as polyethylene and polypropylene, polyolefin resin, such as polyethylene terephthalate, cellulosic resin, such as triacetyl cellulose and butyl cellulose, polystyrene, polyurethane, vinyl chloride, acrylic resin, polycarbonate resin and polyester resin are included.

As shown inFIG. 5, the inclination of the windshield12on which a virtual image is projected varies in different types of vehicles in which the head-up display device11is installed. Therefore, in order to cause the virtual image to be projected on a predetermined projection area E of the windshield12, it is necessary to move the position of the head-up display device11so that the radiation direction of the display light L from the head-up display device11is changed.

According to the head-up display device11of this embodiment, in order to change the radiation direction of the display light L, first, the reflector23whose radiation direction is not suitable is removed from the housing21. Then, the reflector23is replaced with a reflector23which has reflecting surfaces31of a suitable inclined angle corresponding to the inclination of the windshield12which is mounted on the vehicle.

In this way, as shown inFIG. 6, the reflection angle of the display light L on the reflector23can be easily corrected to an angle which suits the windshield12of the vehicle.

That is, according to this embodiment, by removing the reflector23from the housing21, and incorporating a reflector23which has reflecting surfaces31of an inclined angle corresponding to the inclination of the windshield12which is mounted on the vehicle, it can be very easy to cause the head-up display device11to be suited for the carrying vehicle.

Therefore, it is unnecessary to correct by changing the angle of a flat mirror according to the type of a vehicle, or changing the position of the indicator which irradiates an image as applied when the flat mirror is used as the reflector, and thus the cost increase because a different housing is prepared for various types of vehicles can be avoided.

Second Embodiment

Next, a head-up display device11according to a second embodiment is described.

The same structure and the same components as those in the above-mentioned first embodiment are given the same symbols, and their descriptions are omitted.

As shown inFIGS. 7 and 8, in the second embodiment, a reflector41, which is formed by reversing the front and back surfaces of the reflector23used in the first embodiment, is used after being attached in the housing21of the head-up display device11.

That is, in the reflector41, the back surfaces opposite to the front surfaces of the slopes32, on which a mirror finishing is performed with aluminum vapor deposition, of the linear Fresnel lens34become the reflecting surfaces31.

Therefore, the display light L from the indicator22enters from the back surface34bof the linear Fresnel lens34which forms the reflector41, is reflected by the reflecting surfaces31which are formed with the back surfaces of the slopes32, further exits from the back surface34bof the linear Fresnel lens34, and is led to the windshield12through the enlargement mirror24.

As shown inFIG. 9, when the linear Fresnel lens34is formed with injection molding or the like by using a metal mold42, in a processed surface34aof the linear Fresnel lens34, peaks34care formed with valleys42aof the metal mold42, and valleys34dare formed with peaks42bof the metal mold42. When the metal mold42is manufactured with machining such as cutting, the peaks42bcan be easily formed to have an acute angle, but it is difficult for the valleys42ato be formed to have an acute angle because a cutting tool does not arrive. Therefore, in the linear Fresnel lens34fabricated with the metal mold42, although it is easy to form the valleys34dof an acute angle, the peaks34cmay be roundish without being formed to have an acute angle as compared with the valleys34d. Then, as shown inFIG. 10, when the display light L is reflected on the processed surface34aof the linear Fresnel lens34, the display light L is reflected diffusely by the roundish peaks34c, and there is a possibility that flare occurs with the diffusely reflected light La so that the virtual image may become hazy.

In contrast, in the reflector41according to the second embodiment, since the back surfaces opposite to the front surfaces of the slopes32, on which a mirror finishing is performed with aluminum vapor deposition, of the linear Fresnel lens34become the reflecting surfaces31, the valleys34dof an acute angle at the side of the processed surface34abecome peaks when viewed from the side of the back surface34b. Therefore, in the reflector41of this second embodiment, the display light L can be prevented from being diffusely reflected at the peaks, and thus it can be avoided that the virtual image becomes hazy due to the occurrence of flare.

In the reflector41of the above second embodiment, the back surfaces opposite to the front surfaces of the slopes32, on which a mirror finishing is performed with aluminum vapor deposition, of the linear Fresnel lens34become the reflecting surfaces31, and the display light L from the indicator22is caused to enter from the back surface34bof the linear Fresnel lens34and be reflected by the reflecting surfaces31which are formed with the back surfaces of the slopes32. Therefore, as shown inFIG. 11, the display light L is also reflected by the back surface34bof the linear Fresnel lens34, and the virtual image of the windshield12may become hazy due to this reflected light Lb.

Therefore, when the back surfaces opposite to the front surfaces of the slopes32, on which a mirror finishing is performed with aluminum vapor deposition, of the linear Fresnel lens34become the reflecting surfaces31, as shown inFIG. 12, it is preferable that in the linear Fresnel lens34the back surface34bis inclined to the processed surface34awhere the slopes32are formed.

Thus, when the back surface34bis inclined to the processed surface34a, the reflected light Lb of the display light L which is reflected by the back surface34bis led towards a direction greatly different from that of the display light L which is reflected by the reflecting surfaces31, and will not reach the projection area E of the windshield12. Therefore, the trouble that the virtual image becomes hazy due to the reflected light Lb by the back surface34bof the linear Fresnel lens34can be avoided.

In the reflectors23and41using the linear Fresnel lens34, in order to prevent the occurrence of flare as much as possible, it is preferable to form the peaks at the reflection side of the display light L to have an angle as acute as possible, and in order to prevent the reflection of light on the vertical surfaces33, it is preferable to color the vertical surfaces33in black or the like to make light hard to be reflected. By forming the slopes32serving as the reflecting surfaces31as smooth as possible, the occurrence of flare due to the diffuse reflection on the reflecting surfaces31can be suppressed.

Third Embodiment

Next, a head-up display device11according to a third embodiment is described.

The same structure and the same components as those in the above-mentioned first and second embodiments are given the same symbols, and their descriptions are omitted.

As shown inFIGS. 13(a) and13(b), in the third embodiment, a reflector51which has a plurality of reflecting plates52is used in the head-up display device11. Each of these reflecting plates52includes a mirror formed in a rectangular shape viewed from top, and the front surfaces of these reflecting plates52become reflecting surfaces53. The short edges of these reflecting plates52are mutually connected by link mechanisms54, and therefore are arranged in parallel with each other and inclined at the same angle.

Each of the link mechanisms54includes a fixed link55which supports one end of each of the short edges of the reflecting plates52, and a movable link56which supports the other end of each of the short edges of the reflecting plates52. A hole (not shown in the figure) is formed at one end of each of the short edges of the reflecting plates52, and a rotation pin57which is provided in the fixed link55is inserted into the hole. Thereby, the reflecting plates52are rotatably connected to the fixed links55. A long groove58which is extended in the widthwise direction of the reflecting plate52is formed at the other end of each of the short edges of the reflecting plates52, and a sliding pin59which is provided in the movable link56is slidably inserted into the long groove58.

In the reflector51which includes such link mechanisms54, by allowing the movable links56to slide, each of the reflecting plates52rotates around the connecting place with the fixed links55. In the reflector51, if the movable links56are moved in the direction of arrow A inFIGS. 13(a) and13(b), each of the reflecting plates52rotates in the direction of arrow B while the parallelism and the same inclination angle are maintained, and thus each of the reflecting plates52is laid down so that the inclination angle decreases. Conversely, if the movable links56are moved in the direction of arrow C as shown inFIGS. 14(a) and14(b), each of the reflecting plates52rotates in the direction of arrow D while the parallelism and the same inclination angle are maintained, and thus each of the reflecting plates52is raised up so that the inclination angle increases.

Thus, according to the above third embodiment, by adjusting the inclination angle of the plurality of reflecting plates52which are arranged in parallel with each other and inclined at the same angle, it can be very easy to allow the head-up display device to be suited for the carrying vehicle.

The movable links56of the reflector51may be moved manually or electrically.

In order to describe further advantages of the present invention, reference examples are shown inFIGS. 15 and 16.

FIGS. 15 and 16show a head-up display device in which one piece of flat mirror61is provided in a housing21as a reflector.

When the flat mirror61is used as the reflector in this way, in order to mount various kinds of vehicles the inclinations of whose windshields12, on which a virtual image is made to be projected, vary, the position of the indicator22must be moved to change the radiation direction of the display light L, as shown inFIG. 15, or the angle of the flat mirror61must be changed, as shown inFIG. 16.

That is, in the head-up display device using the flat mirror61, with the change of structure or shape relative to the housing21, a different housing21has to be prepared for each of various types of vehicles, which becomes a factor of cost increase.

In contrast, according to this embodiment, even if the head-up display device is mounted in various kinds of vehicles the inclination of whose windshields12, on which a virtual image is made to be projected, vary, since the reflectors23or41which has a reflection angle that is adapted for the inclination of the windshield12can be attached, or the reflecting plates52of the reflector51can be adjusted to an angle which is adapted for the inclination of the windshield12, the change of structure or shape relative to the housing21is not required. Therefore, the cost increase due to the fact that a different housing21is prepared for each of various types of vehicles can be avoided.

Although the reflector51which has the reflectors23or41or a plurality of reflecting plates52which form the linear Fresnel lens34is used in the above-mentioned embodiment, it is also possible to use a non-regular-reflection type holographic mirror for which the incidence angle differs from the reflection angle as an reflector and to make the reflector which includes the non-regular-reflection type holographic mirror to be removable from the housing21.

If the reflector which includes the non-regular-reflection type holographic mirror is included, by incorporating the reflector including the non-regular-reflection type holographic mirror of a suitable reflection angle corresponding to the inclination of the windshield12which is mounted on a vehicle into a housing, it can be very easy to make the head-up display device11to be suited for the vehicle on which it is mounted.

The present invention is not restricted to the above-described embodiments, and suitable modifications, improvements, and the like can be made. Moreover, the materials, shapes, dimensions, numbers, installation places, and the like of the components in the above embodiments are arbitrarily set as far as the invention can be attained, and not particularly restricted.

Although the present invention is described in detail with reference to the embodiments, it is apparent that various modifications and amendments may be made by those skilled in the art without departing from the spirit and scope of the invention.

According to the present invention, a head-up display device which can be applied to various types of vehicle can be provided without causing cost increase.