JPH07239649A - Head-up display for vehicles - Google Patents

Abstract

(57) [Summary] [Construction] In a vehicle head-up display comprising a reflection hologram 5 mounted on a windshield of a vehicle and a light emitting display means for projecting the information light onto the reflection hologram, the information light is A vehicle head-up display characterized in that a surface formed by an incident direction of an incident light toward a hologram and an emitted light visually recognized after being diffracted by the hologram has an inclination with respect to a surface of the windshield. [Effect] The visibility of the diffracted image is extremely good, and this effect is not affected by the presence or absence of external light.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a holographic display, and more particularly to a vehicle using a hologram,
The present invention relates to a head-up display for vehicles such as aircraft (hereinafter referred to as vehicles).

[0002]

2. Description of the Related Art As a display for displaying information of instruments and the like in a vehicle or the like, a light (called information light) having information projected from a light emitting display means such as a liquid crystal display device is used as a half mirror mounted on a windshield. There has been proposed a head-up display (hereinafter abbreviated as HUD) that allows a driver to project information onto a combiner made of a hologram and read the information while looking ahead (Japanese Patent Laid-Open No. 1-27-27).
6190 publication).

In particular, the HUD using a hologram as a combiner has an advantage that not only can the information light be diffracted to form an image at an arbitrary position, but also a virtual image of high brightness can be obtained without spoiling the foreground. Therefore, it has attracted particular attention in recent years. This is because the information light emitted from the light emitting display means is irradiated toward the reflection hologram provided on the windshield surface of a vehicle or the like at an incident angle θ ₁ , and the hologram diffracts the information light at a diffraction angle θ _2. The information contained in the information light is visually recognized as a virtual image (see FIG. 1).

However, such a HUD has a θ ₁
And θ ₂ are equal, a display image formed by diffracting the information light by the hologram (called a diffraction image) and a display image formed by reflecting on the front and back surfaces of the windshield (called a reflection image) Since they overlap, there is a drawback that the visibility is poor. In addition, when θ ₁ and θ ₂ are close to each other, the reflection images reflected on the front and back surfaces of the glass are visible above and below, which is unsightly and reduces the visibility of the diffraction image.

Further, when light is transmitted through the hologram from the outside of the vehicle or the like, the light is reflected on the back surface of the windshield (inside the vehicle), and the light of a specific wavelength therein (specified when the hologram is exposed) Since the light having the given wavelength) is diffracted by the hologram and becomes noise light (referred to as flare light) with respect to the information light (see FIG. 7), there is a drawback that the visibility of the diffracted image is reduced.

[0006]

Therefore, as a result of diligent studies for solving the above-mentioned drawbacks, the present inventor has found that a good result can be obtained by providing a specific relationship between the hologram, the light source, and the viewpoint. The inventors have found that the following can be obtained and reached the present invention. Therefore, a first object of the present invention is to provide a head-up display excellent in visibility of a displayed image. It is a second object of the present invention to provide a head-up display that does not visually recognize a specular reflection image of information light by a windshield. Furthermore, a third object of the present invention is to provide a head-up display in which the influence of flare light due to light incident from the outside of a vehicle or the like is reduced.

[0007]

The above objects of the present invention include a vehicle comprising at least a reflective hologram mounted on a windshield of a vehicle, and a light emitting display means for projecting information light onto the reflective hologram. In the head-up display for use, the surface formed by the incident light of the information light on the hologram and the outgoing light visually recognized after diffraction by the hologram has an inclination from the vertical with respect to the surface of the windshield and, if necessary, Accordingly, the sum of the angle of attachment of the windshield and the angle of incidence of the component of the light incident on the hologram in the plane direction perpendicular to the windshield surface on the hologram to the hologram is 90 ° or more. Achieved by a featured vehicle head-up display.

The reflection hologram (simply referred to as a hologram) used in the present invention is not particularly limited, and known holograms can be used. As such a hologram, a volume such as Lippmann type
In addition to phase holograms, holograms of various types such as emboss type and rainbow type can be mentioned, but from the viewpoint of high diffraction efficiency, it is particularly preferable to use volume / phase type holograms.

As the hologram material, various photosensitive materials such as polyvinylcarbazole, acrylic photopolymer, dichromated gelatin, photoresist, silver salt and the like can be usually used. The hologram is usually several tens of mm to several hundreds of mm square and has a thickness of several μm to several tens of μm, and its size and shape may be appropriately designed upon use.

The hologram may be provided on the surface of the windshield or may be enclosed between two glass plates constituting the laminated glass used as the windshield. From the viewpoint of preventing the hologram from being damaged, the two holograms are included. It is preferable to enclose between the glass plates. When arranged on the surface, it is preferable to provide a protective film. Further, the position where the hologram is arranged may or may not be in front of the driver and can be appropriately determined.

The hologram and the light source are positioned at an angle of 9 between the surface containing the incident light and the visually recognized diffracted light and the windshield surface.
It is decided not to be 0 °. Normally, the hologram is provided in parallel with the windshield surface, and therefore the angle between the surface determined by the incident light on the hologram and the visually recognized diffracted light and the hologram surface is not 90 °. That is,
The hologram is exposed by arranging exposure light sources on both sides of the hologram photosensitive material at the time of manufacturing the hologram, and at that time, a surface formed by both incident lights incident from these light sources toward the hologram photosensitive material. The exposure light source is arranged so that the hologram surface and the hologram surface are not perpendicular to each other.

The light emitting display means for projecting the information light on the hologram in the present invention is not particularly limited as long as it has a function of emitting light to display information. As such a light emitting display means, for example, a display body including a light receiving display element such as a liquid crystal display element and a hot cathode tube (HC
T), cold cathode tubes, fluorescent display tubes (VF), halogen lamps, light emitting diodes (LEDs), and other light sources may be combined.

If object light having two or more wavelengths is used during hologram production, a virtual image to be visually recognized can be a multicolor image corresponding to the number of object light used. It is preferable to use a color liquid crystal display element including a color filter and a transmission type twisted nematic type liquid crystal element or a super twisted nematic type liquid crystal element as a light emitting display means for forming a multicolor image.

In the present invention, the inclination θ of the surface of the information light including the incident light to the hologram and the outgoing light visually recognized after diffraction (referred to as the incident light surface) with respect to the windshield surface.
Is determined so that any reflected light of the information light by the windshield does not enter the eyes of the driver. Here, "any reflected light from the windshield" is a concept that includes not only specularly reflected light from the driver-side glass surface of the windshield but also specularly reflected light from the glass surface outside the vehicle.

Therefore, in general, it is sufficient that the inclination is ± 20 ° or more from the plane perpendicular to the windshield in the forward direction of the driver, and the vehicle specifications such as the distance from the issuing display means to the windshield. It is appropriately determined according to here,
Plus (+) indicates a rightward inclination with respect to the vertical plane, and minus (-) indicates a leftward inclination. In this way, the diffracted light obtained by diffracting the information light by the hologram is visually recognized, whereas the information light specularly reflected on the back surface or the front surface of the windshield is reflected in a direction different from that of the diffracted light. The driver can visually recognize only the virtual image corresponding to the required information.

In the present invention, the sum of the mounting angle of the windshield and the incident angle of the information light on the hologram surface is 90.
By setting the angle to be equal to or more, it is possible to significantly reduce the influence of flare light which transmits the hologram from the outside of the vehicle and reduces the visibility of the diffracted image. That is, when the angle is 90 °, only external light entering from the horizontal direction becomes noise light, and when the angle is 90 ° or more, external light entering from below the horizontal direction becomes noise light (see FIG. 9).

Therefore, the visibility of the diffracted image deteriorates because
For example, there is a vehicle on the horizon where the sun with relatively low illuminance is on the horizon, or at night, on a slope with streetlights. However, in any case, since the light is weak and the time is short, there is no problem, and therefore the visibility is good in most cases. The HUD of the present invention can be suitably used not only for vehicles such as automobiles but also for vehicles such as ships and aircraft.

[0018]

According to the head-up display of the present invention, since only the diffracted light by the hologram is visually recognized,
The visibility of the diffraction image is extremely good. Further, when the sum of the mounting angle of the windshield and the incident angle of the information light is 90 ° or more, the visibility of the diffracted image is good in the conventional case even when there is external light that causes flare light. .

[0019]

EXAMPLES The present invention will be described in more detail below with reference to Examples, but the present invention is not limited thereto. Example 1. FIG. 2 is a conceptual perspective view showing the head-up display of this embodiment. The information light 2 projected from the light emitting display means 1 is a hologram 5 mounted on the windshield 6.
Is diffracted by and becomes the diffracted light 4 which reaches the eyes 12 of the driver. At this time, the incident light and the visually recognized diffracted light include the normal line 9 to the windshield 6 as shown in FIG. 3, are on the same side (that is, right side) with respect to the plane forming the angle of θ _{3 with} the information light, and are incident. The angle θ ₁ and the diffraction angle θ ₂ are equal.

The position of the hologram is 2 to the left of the driver.
The angle is about 0 ° to 40 °, that is, the surface formed by the information light 2 incident from the issuing / displaying means 1 toward the hologram 5 and the diffracted light 4 diffracted by the hologram 5 and directed to the driver's eye, and the windshield. The angle with the glass 6 is about 50 ° to 70 °, and both surfaces are inclined about 20 ° to 40 ° from the vertical. Therefore, the reflected light 3 from the front and back surfaces of the windshield does not overlap the hologram diffracted light 4, and a clear hologram diffracted image can be visually recognized.

Example 2. In this example, unlike Example 1, the hologram diffraction grating is located at the lower right of the windshield (see FIG. 4). The information light 2 projected from the light emitting display means 1 is
The light is diffracted by the hologram 5 mounted on the windshield 6 and becomes diffracted light 4 which reaches the eyes 12 of the driver. At this time, the incident light and the visually recognized diffracted light include the normal line 9 as shown in FIG. 5, are on the same side with respect to the plane forming an angle of θ _{3 with} the information light, and are incident angle θ ₁ and diffraction angle θ ₂ Is equal to.

The position of the hologram is 2 to the left of the driver.
The angle is about 0 ° to 40 °, that is, the surface formed by the information light 2 incident from the issuing / displaying means 1 toward the hologram 5 and the diffracted light 4 diffracted by the hologram 5 and directed to the driver's eye, and the windshield. The angle with the glass 6 is about 50 ° to 70 °, and both surfaces are inclined about 20 ° to 40 ° from the vertical. Therefore, the reflected light 3 from the front and back surfaces of the windshield does not overlap the diffracted light 4 by the hologram, and a clear hologram diffraction image can be visually recognized.

Example 3. In this example, unlike the cases of Examples 1 and 2, the hologram diffraction grating is located above the center of the windshield (see FIG. 6). The information light 2 projected from the light emitting display means 1 installed on the ceiling of the automobile is the windshield 6
The diffracted light 4 is diffracted by the hologram 5 attached to the
And reaches the eyes 12 of the driver. At this time, the incident light and the visually recognized diffracted light include the normal 9 as shown in FIG.
It is on the same side with respect to the surface forming an angle of θ _{3 with} the information light, and the incident angle θ ₁ is larger than the diffraction angle θ ₂ .

The position of the hologram is 2 to the left of the driver.
The angle is about 0 ° to 40 °, that is, the surface formed by the information light 2 incident from the issuing / displaying means 1 toward the hologram 5 and the diffracted light 4 diffracted by the hologram 5 and directed to the driver's eye, and the windshield. The angle formed with the glass 6 is about 50 ° to 70 °, and both surfaces are inclined from the vertical by about 20 ° to 40 °. Also in this case, since the directions of the reflected light 3 from the front and back surfaces of the windshield and the diffracted light 4 by the hologram are different from each other, a clear hologram diffraction image can be visually recognized.

Example 4. FIG. 8 shows a case where the hologram is mounted in the windshield slightly to the right of the driver and slightly below the center in the vertical direction. In this case, the driver looks at the light source outside the vehicle together with the information light to the left and slightly downward. The position of the hologram should be 20 to the left of the driver.
It is preferably 40 °, and 1 to 10 ° below the horizontal direction, and particularly preferably 3 to 7 ° below.

In this case, for example, during the daytime, noise is generated only when the sun is located at about 20 to 40 ° to the right of the driver and 1 to 10 ° below the horizontal line. Becomes Here, assuming that the mounting angle of the windshield is 35 °, the incident angle of the information light on the reflection hologram is 56 to 65 ° measured from the normal line set up on the windshield.
Becomes On the other hand, since the diffraction angle of the information light is generally 57 to 65 °, the reflection type hologram is quite close to the regular reflection type. Further, since the specular reflection light of the information light from the light emitting display means 1 on the glass surface is reflected in the direction of the reflected light 3, it is not necessary to visually recognize an extra image due to the specular reflection on the glass surface.

The information light 2 projected from the light emitting display means 1 is diffracted by the hologram 5 mounted on the windshield 6 and becomes the diffracted light 4 which reaches the eyes 12 of the driver. At this time, as shown in FIG. 9, the incident light 13 of the light source 14 outside the vehicle is incident from below in the horizontal direction of 1 to 10 ° as described above, is reflected by the back surface of the windshield 6, and is diffracted by the hologram 5. It becomes noise 13 and reaches the eyes 12 of the driver. That is, in this case, there is a flare light reduction effect for cases other than the above angle range. Since the incident angle of the information light, the visually recognized diffraction angle, and the windshield mounting angle are normally uniquely determined, the effect of the present invention can be obtained in a wider range.

Example 5. This embodiment is a case where the reflection hologram is installed in the windshield on the right side of the driver and in the lower part in the vertical direction (see FIG. 10). In this case, the driver sees the light source outside the vehicle on the lower right side together with the information light. In addition, the position of the hologram is 15 to 35 ° to the right of the driver and 10 to 25 from the horizontal direction.
It is preferable that the temperature is lowered by 15 °, preferably 15-20 °.

In this case, for example, in the daytime, the flare light is generated only when the sun is between about 15 and 35 degrees to the left of the driver and at a position which is 10 to 25 degrees lower than the horizontal line. It will be. When it becomes larger than about 20 °,
In the case of a vehicle having a bonnet, the outside light does not enter because of the obstacle. Here, the mounting angle of the windshield is 3
Assuming 5 °, the incident angle of the information light on the reflection hologram is 65 to 80 ° as measured from the normal line standing on the windshield. On the other hand, since the diffraction angle of the information light is generally 57 to 65 °, the reflection hologram is a little closer to the regular reflection type. Moreover, since the specular reflection light of the information light from the light emitting display means on the glass surface is reflected in the direction of the reflection light 3,
It is not necessary to see an extra image due to regular reflection on the glass surface.

Information light 2 projected from the light emitting display means 1
Is diffracted by the hologram 5 mounted on the windshield 6, and becomes diffracted light 4 which reaches the eyes 12 of the driver.
At this time, as described above, the incident light 13 of the light source 14 outside the vehicle is incident from below at 15 to 30 ° in the horizontal direction as shown in FIG.
Diffracted into flare light 13 by the driver's eye 1
Reach 2. That is, in this case, there is a flare light reduction effect for cases other than the above angle range. Since the incident angle of the information light, the visually recognized diffraction angle, and the windshield mounting angle are usually uniquely determined, the effect of the present invention can be obtained in a wider range.

[Brief description of drawings]

FIG. 1 is a schematic explanatory diagram of a head-up display.

FIG. 2 is a conceptual perspective view of a head-up display of the present invention.

FIG. 3 is a schematic top side view of the head-up display of the present invention.

FIG. 4 is a conceptual perspective view of a head-up display of the present invention.

FIG. 5 is a schematic top side view of the head-up display of the present invention.

FIG. 6 is a schematic explanatory diagram of a head-up display of the present invention.

FIG. 7 is a schematic explanatory diagram of a head-up display when external light acts.

FIG. 8 is a schematic explanatory diagram of a head-up display of the present invention.

FIG. 9 is a schematic sectional view of a head-up display of the present invention.

FIG. 10 is a schematic explanatory diagram of a head-up display of the present invention.

FIG. 11 is a schematic sectional view of a head-up display of the present invention.

[Explanation of symbols]

1 Information light irradiation device combining liquid crystal display element and hot cathode tube (HCT) 2 Information light 3 Reflected light (Ia) 4 Diffracted light (Ib) 5 Reflective hologram 6 Windshield 9 Normal to windshield 11 Windshield Mounting angle (θ ₄ ) 12 Driver's eye 13 External light 14 External light source 15 Steering wheel

Claims (2)

[Claims] 1. A vehicle head-up display comprising at least a reflection hologram mounted on a windshield of a vehicle and a light emitting display means for projecting the information light onto the reflection hologram. A head-up display for vehicles, characterized in that a surface formed by the incident light and the outgoing light visually recognized after being diffracted by the hologram has an inclination from the vertical with respect to the surface of the windshield. 2. The sum of the mounting angle of the windshield and the incident angle of the component of the incident light that the information light is directed to the hologram in the surface direction perpendicular to the windshield surface to the hologram is 90 ° or more. The vehicle head-up display described in.