JPH06199149A - Head up display - Google Patents

Abstract

PURPOSE:To bring respective color tones of transmitted light from the vehicle outside and reflected light on the vehicle outside respectively close to colorlessness, secure the transparent field of view, and improve safety by exposing a hologram used as a combiner by means of a beam of light having plural wave lengths corresponding to three primary colors. CONSTITUTION:An information display source arranged under windshield glass 7 in a vehicle body gives out a beam of light 3 from a light source 6 as information to be displayed through a lens system 4 being a collimator and a display body 5. The beam of light 3 is radiated to/diffracted by a combiner 2 composed of a hologram arranged in the windshield glass, and is confirmed visually by a driver in a observational position 1. A function as the collimator can be given to a hologram, and a display image of speed display 8 or warning display 9 can be formed in the distance. By the way, the hologram is exposed by a beam of light having plural wave lengths corresponding to three primary colors selected so as to bring respective color tones of external light transmitted to the vehicle inside from the vehicle outside and reflected light observed on the vehicle outside respectively close to colorlessness.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a head-up display (hereinafter referred to as HUD) device.

[0002]

2. Description of the Related Art HUD has recently been used as a method of displaying information to a driver in an automobile or the like.
This is because the optical information projected from the information projection means such as a liquid crystal display device is projected on a combiner composed of a hologram or a half mirror incorporated in the windshield of an automobile, etc., and the driver almost moves the viewpoint from the driving state. The information can be read without any need.

In particular, a hologram using a hologram as a combiner can have a lens function and the like as well as a function of diffracting optical information toward the driver.
It is possible to diffract optical information in the direction of the driver's visual field, or to form an image at any position without using any other optical system such as a lens, and without impairing the foreground brightness. It is effective as a combiner for HUD because it has a feature that a high-intensity display image can be obtained.

FIG. 8 is a conceptual diagram showing an example of a conventional HUD. A light ray 43 including information to be displayed, which is emitted from a light source 46 and has passed through a transmissive liquid crystal display element 45 through a lens system 44, is irradiated on a hologram 42 provided on a windshield 47 of a vehicle body, diffracted, and then a driver. It is visually recognized at the observation position 41.

The lens system 44 has a function as a collimator, and the function is the hologram 4.
It can be attached to 2 and speed display 48, warning display 49
It is also possible to form the display image of (1) in the distance.

Further, since the hologram 42 has a wavelength selection function, an image of a desired color can be displayed. Usually, the color is often single, but multi-color display by multiple exposure is also possible, and the amount and quality of display information can be improved. For example,
By setting the speed display 48 in green and the warning display 49 in red, it becomes possible to more accurately transmit information to the driver.

[0007]

As described above, since the conventional holographic HUD diffracts a light beam of a specific wavelength, when the driver looks outside through the hologram, the color of the transmitted light is the diffraction of the hologram. It is a complementary color to the color (display color) corresponding to the wavelength. That is, when the display color is only green as shown in FIG. 5, colorless light from the outside 22 (also referred to as white light, but hereinafter, white light is generically called colorless light, and white is also colorless. When transmitted through the hologram 21, the light is partially reflected and diffracted by the diffraction grating inside the hologram, and the reflected light 23 becomes green. Therefore, the transmitted light 24 becomes magenta (pink to red) which is a complementary color of the transmitted light 24, and is perceived as an irritating and unpleasant color for the driver 25. Further, as a result, the color tone of the background is affected, and the visibility of the condition outside the vehicle such as the road during driving is impaired, which is a safety issue.

On the other hand, as shown in FIG. 6, outside light 32 is applied to an observer 35 (a pedestrian, a driver of an oncoming vehicle, etc.) outside the vehicle.
Due to the angle dependence of the diffraction wavelength of the diffraction grating inside the hologram 31, the reflected color of the color changes greatly from red (near the front) 33 to green (oblique observation) 34 depending on the angle of observation, which also gives an unpleasant impression. there were.

FIG. 7 is a chromaticity diagram showing a simulation result of the color change of the reflected color. The chromaticity diagram is JIS-Z8
The color is quantitatively expressed by the chromaticity coordinates x and y defined by 701. The point X shown as a light source in FIG. 7 represents colorless. The closer the color of the hologram is to this point, the more colorless it becomes, and the more preferable the color is for the observer.

However, the color of the reflected light of the monochromatic hologram used in the conventional HUD is, for example, a wavelength of 545 nm,
When the diffraction efficiency is 60%, it changes as shown by a solid diamond in FIG.
That is, it turns out that the color near the front becomes red, and as it becomes oblique, it changes greatly to orange, yellow, and green.
In particular, when viewed from the front, the stimulating color is red, which gives an unpleasant impression to the observer.

In order to improve the color tone of the reflected light for an observer outside the vehicle, Japanese Patent Laid-Open No. 4-110984 discloses a first color tone for improving the color tone of the reflected color by the first hologram used for display. A HUD for stacking or multiple-exposing a second hologram that reflects a color close to the complementary color of the reflection color of the hologram is disclosed. However, since the HUD is composed of two-color holograms, the color tone may not be improved completely. there were. Especially, it is often used as a display color.
With respect to the green light of 60 nm, it is difficult to improve the color tone of the reflected color in practice because there is no light of a wavelength corresponding to the complementary color, and there is a drawback that only the color tone of the reflected color is improved. It was only.

Further, in Japanese Patent Laid-Open No. 3-179418, in order to improve the color tone of light transmitted through a combiner,
A wavelength λ that is a complementary color to the reflection wavelength λ1 of the display hologram.
Although a HUD is disclosed in which an optical element that reflects or attenuates two light rays is disclosed, the HUD is similar to the above-described known example.
Since the color is corrected by the color configuration, it has the same drawback that it cannot be completely improved for green light, and it is only a means for improving the color tone of transmitted light.

[0013]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and includes at least a light source and a display for displaying information to be displayed, and generates information to be displayed as a light beam. In a head-up display including at least an information display source, and a combiner that is provided on a windshield of a vehicle and diffracts the light rays toward an observer in the vehicle, the combiner is provided inside the vehicle from outside the vehicle through the combiner. At least 3 selected to make the color of transmitted external light and the color of reflected external light from the combiner observed outside the vehicle close to colorless.
It is intended to provide a head-up display, which is a hologram exposed by light rays of a plurality of wavelengths corresponding to primary colors (red, green, blue).

[0014]

When the HUD according to the present invention is used, the color tone of the transmitted light and the color tone of the reflected light of the combiner are closer to colorless as compared with the conventional hologram, so that the driver is provided with a transparent visual field with no complementary color and safety is improved. In addition to increasing the color, there is little color change depending on the angle of observation with respect to an external observer, and a HUD having an almost colorless appearance color can be obtained. In particular, the color tone can be effectively improved even for green light of about 500 to 560 nm which is frequently used as a display color.

At the same time, since this combiner can be used as a combiner for color display, it is possible to obtain a color HUD whose transmitted and reflected colors are almost colorless.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a conceptual diagram showing an example of the HUD of the present invention. An information display source is provided below the windshield 7, and the information display source emits light from a light source 6 through a lens system 4 which is a collimator and passes through a display body 5 formed of a transmissive liquid crystal display element. The information to be displayed is emitted as a light ray 3. This light ray 3 is applied to the combiner 2 made of a hologram provided on the windshield 7 of the vehicle body, diffracted, and visually recognized by the driver at the observation position 1.

The lens system 4 has a function as a collimator, and this function can be added to a hologram, so that the display images of the speed display 8 and the warning display 9 can be formed at a distance. It will be possible.

If desired, another hologram or lens for aberration correction may be arranged between the display body 5 and the combiner 2.

Further, since the hologram has a wavelength selection function, an image of a desired color can be displayed, and further, multi-exposure or stacking of a plurality of holograms enables multi-color display, and the quantity and quality of display information. Can be improved. For example, by setting the speed display 8 to green and the warning display 9 to red, it becomes possible to more accurately transmit information to the driver.

FIG. 2 is a schematic sectional view showing an example of the structure of the hologram of the present invention. In this example, a structure example is shown in which three holograms, which are independently exposed by light rays having respective wavelengths corresponding to the three primary colors, are stacked. The first hologram 11 reflects and diffracts a light beam having a wavelength of 607 nm (red), the second hologram 12 reflects and diffracts a light beam having a wavelength of 545 nm (green), and the third hologram 13 has a wavelength of 450 nm.
It was exposed so as to reflect and diffract a light beam of nm (blue).

The hologram used as the combiner of the HUD of the present invention may be the laminated type shown in FIG. 2, but it is obtained by so-called multiple exposure in which one light-sensitive material is irradiated with laser light of a plurality of wavelengths. It is more preferable to use one hologram in order to prevent the deviation of the image of each wavelength due to the stacking and the decrease of the transmittance of the combiner.

Here, each hologram is exposed so that the inclinations of the diffraction gratings formed therein are all the same, and therefore all the incident angles of the light rays incident on the combiner composed of such holograms are set. By making the light rays of the same color the same, the diffraction angles diffracted by the hologram are also the same for all the color light rays. If these angles are different, the direction diffracted by each color ray will be different,
What should originally be colorless is divided into three colors, which is instead perceived as an unpleasant color by the observer.

As described above, in order to manufacture a reflection type hologram in which the inclinations of the diffraction gratings in each hologram are all the same, the incident angle of the laser beam applied to both sides of the hologram photosensitive material with respect to the hologram photosensitive material. Should be the same for all rays on each side of the photosensitive material. Even when the incident angles of the laser light at the time of exposure are not the same, if the relationship between the two angles at which the laser light of one wavelength is incident on both sides of the hologram photosensitive material is adjusted, the diffraction grating formed inside will be The slopes can be the same.

FIG. 3 is a chromaticity diagram showing the color change of the external light reflection color of the three primary color exposure holograms thus produced.
The hologram of the present embodiment is a three-layered type, red has a wavelength of 607 nm and a diffraction efficiency of 80%, green used for display has a wavelength of 545 nm and a diffraction efficiency of 73%, and blue has a wavelength of 450 nm and a diffraction efficiency. 94%. In FIG. 3, black triangles are the results of color change calculation by simulation, and squares are the actual measurement values measured by a color luminance meter. Although it looks green in the front, the color tone is almost colorless when viewed diagonally.

Compared with the case of the monochromatic hologram shown in FIG. 7, the color change is small, the stimulating red color is eliminated, and the color tone of the reflected color is improved. Moreover, the simulation and the measured value show a good agreement.

Further, since the transmitted color in this case is considered to have a complementary color relationship with the reflected color, it has a color tone close to the position of point symmetry with respect to the light source x mark in FIG. Since the transmitted color seen by the driver is an observation angle corresponding to oblique observation, the color tone is close to colorless. As described above, the hologram according to the present invention was able to improve the color tone of both the reflected color and the transmitted color as compared with the conventional hologram.

Further, by enclosing the hologram of this embodiment in the windshield laminated glass of the vehicle to form a combiner, the color tone of the external light reflection color and the transmission color is improved.
We were able to realize UD.

A hologram is usually several tens of meters.
From an area of 100 to 100 mm square, from several μm to several 10
It has a thickness of about μm and has a light diffraction function. Although such a hologram is desirable in that a volume / phase type hologram such as a Lippmann type can obtain high diffraction efficiency, a hologram called an embossed type or a rainbow type can be widely used. As the hologram material, various photosensitive materials such as polyvinyl carbazole, acrylic-based photopolymers, dichromated gelatin, photoresists, and silver salts can be used.

Such a hologram is provided in the windshield, for example, the surface of the windshield (vehicle outer surface).
It may be provided on the inner surface of the vehicle or on the inside surface of the vehicle, but in view of protection of the hologram in particular, it is preferably enclosed and used in the windshield which is a laminated glass.

The information display source in the present invention has a function of emitting light to display, and a hot cathode tube (HC) is attached to a display body composed of a so-called light receiving display element such as a liquid crystal display element.
T), a cold cathode tube, a fluorescent display tube (VF), a halogen lamp, an LED, or the like for irradiating light emitted from a light source, or may have these functions together.

When the combiner of the present invention is used for color display, examples of the liquid crystal display device include a color liquid crystal display device including a color filter and a transmission type twisted nematic type liquid crystal device, a super twisted nematic type liquid crystal display device and the like. It can be preferably used, and a light beam emitted from one light source can be irradiated as a light beam of a desired color.

In this way, light beams of a plurality of colors can be emitted from the same information display source, and when these light beams of a plurality of colors are displayed simultaneously, the display images are displayed in an overlapping manner, and conversely In order to prevent overlapping of displayed images, a combination of a color filter and a light source or a color liquid crystal display element may be controlled as necessary so that light beams of a plurality of colors are not simultaneously irradiated.

Alternatively, instead of using the light receiving type display element, the light source itself may be patterned and arranged to generate specific information as light. In the case where the light source is used together with the light receiving type display element, an appropriate light beam collimating means such as a lens system or a curved reflecting mirror, and a suitable light guiding means such as a light guide plate are provided between the light receiving type display element and the light source. You may arrange. Further, if necessary, an optical polarization means or KN is provided in the optical path until the light is projected on the hologram.
A non-linear optical element such as O ₃ may be arranged.

When the HUD of the present invention is displayed in color, if the distance from the combiner to the display image is the same for each color, color display can be performed in the same plane, and if the display is changed depending on the color, the display color will change. It is possible to obtain a three-dimensional image having different observed distances of the display image.

Further, in the present embodiment, the three-color display hologram has been described, but the same effect can be obtained even with a hologram capable of displaying four or more colors. Further, the hologram in the present invention is not limited to the reflection hologram as described above, and may be a HUD using a transmission hologram.

As a second embodiment, the wavelength of the light rays of the three primary color exposures is red, the wavelength is 600 nm, the diffraction efficiency is 60%,
Wavelength of 545 nm as a green color used for display, diffraction efficiency of 60
%, A hologram having a wavelength of 430 nm as a blue color and a diffraction efficiency of 60% was used. FIG. 4 is a chromaticity diagram showing a simulation result of a change in external light reflection color of the hologram of this embodiment. Since the simulation and the measured value show a very good match as shown in FIG. 3, only the simulation result is shown in this embodiment.

As can be seen from FIG. 4, the change in the external light reflection color of the hologram of this embodiment is further improved as compared with the previous embodiment, and is close to colorless. By thus selecting the three wavelengths, the color tone can be optimized.

Further, by enclosing the hologram of this embodiment inside a windshield laminated glass of a vehicle to form a combiner, it is possible to realize a HUD in which the color tones of external light reflection color and transmission color are improved as in the previous embodiments. You can The structure of the hologram of the present embodiment, the manufacturing method thereof, the light source for the HUD, and the like can be the same as those of the previous embodiments.

[0039]

According to the present invention, since the hologram used as the combiner is exposed by the light rays having a plurality of wavelengths corresponding to the three primary colors, the observer of the driver or the like can see through the combiner from outside the vehicle. The color tone of the transmitted light seen by the driver and the color tone of the reflected light of the external light from the combiner outside the vehicle are closer to colorless than the conventional combiner, giving the driver a transparent view without complementary colors for safety. HUD with high color tone and little color change depending on the angle of observation to outside observers and a color tone close to colorless
Is obtained. Especially, it is often used as a display color.
It is possible to effectively improve the color tone even for green light of about 0 to 560 nm.

Furthermore, the combiner in the present invention is
Since it is possible to display light rays of at least three colors, it is possible to obtain a HUD capable of displaying information in a plurality of colors while the transmitted color from outside the vehicle and the reflected color outside the vehicle are colorless.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing an example of a HUD of the present invention.

FIG. 2 is a schematic sectional view showing an example of the structure of a hologram in the present invention.

FIG. 3 is a chromaticity diagram showing a color change of an external light reflection color of the hologram in the present invention.

FIG. 4 is a chromaticity diagram showing the color change of the external light reflection color of the hologram in the present invention.

FIG. 5 is a conceptual diagram illustrating a transmission color of a conventional hologram.

FIG. 6 is a conceptual diagram illustrating a reflection color of a conventional hologram.

FIG. 7 is a chromaticity diagram showing a change in external light reflection color of a conventional hologram.

FIG. 8 is a sectional view showing a conventional vehicle-mounted HUD.

[Explanation of symbols]

 1: Driver's observing position 2: Combiner 3: Ray containing information 4: Lens system 5: Display element 6: Light source 7: Windshield 8: Speed display 9: Warning display

Claims (5)

[Claims] 1. An information display source that includes at least a light source and a display body that displays information to be displayed and that generates information to be displayed as a light beam; and a windshield of a vehicle that is provided with the light beam inside the vehicle. In a head-up display including at least a combiner diffracting toward an observer, the combiner is a color tone of external light transmitted from the outside of the vehicle to the inside of the vehicle through the combiner, and reflected light of the outside light by the combiner observed outside the vehicle. At least 3 primary colors (red, green, blue) selected so that the color tone of
Head-up display, which is a hologram exposed by light rays of a plurality of wavelengths corresponding to the colors of. 2. The head-up display according to claim 1, wherein the combiner is a single-layer hologram which is multiple-exposed by light rays having a plurality of wavelengths. 3. The head-up display according to claim 1, wherein the combiner is a stack of a plurality of holograms exposed by light rays of a single wavelength or a plurality of wavelengths. 4. The incident angles of light rays of a plurality of colors incident on the combiner are all substantially the same, and the diffraction angles of light rays of a plurality of colors diffracted from the combiner are all substantially the same. The head-up display according to claim 1. 5. The wavelength corresponding to the three primary colors is 580 for red.
The head-up display according to any one of claims 1 to 4, wherein green is about 500 to 560 nm, blue is about 420 to 480 nm.