JPH1152283A - Combiner for headup display device and headup display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a combiner capable of making display easy-to-view in accordance with working environment. SOLUTION: Since this combiner 2 is provided with a photochromic glass plate 9, transmissivity is changed in accordance with external light. Light 5 including information from a light emitting means is diffracted by a hologram 7 enclosed between a transparent glass plate 6 and the plate 9, so that a display picture 4 is visually recognized by a viewer 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combiner for a head-up display device, and to a head-up display device that allows a viewer to view information using the combiner.

[0002]

2. Description of the Related Art As a method of displaying information to a driver or the like in a vehicle, a head-up display (hereinafter, referred to as HUD) is used.
What has been called recently has been used. This is to project the optical information projected from the light emitting means such as a liquid crystal display device on a combiner composed of a half mirror and the like,
The driver can read information from the driving state with almost no movement of his / her eyes.

[0003] As the HUD, a combiner is formed on a windshield, a light emitting means for generating information is installed in a dashboard, and light from the light emitting means is radiated to the combiner and reflected to be viewed by a driver or the like. In addition to a HUD that can be visually recognized by a person, a so-called separately-installed HUD in which a light emitting unit and a combiner are integrated into one is also known. Since this separate type HUD does not form a combiner directly on the windshield, it can easily be installed on the dashboard even after installation to obtain the function of the HUD, can be easily removed, and can be easily removed by the driver. There is an advantage that it can be installed at a desired position.

FIG. 3 is a conceptual diagram showing the configuration of such a conventional separately placed HUD. Here, 21 is a viewer such as a driver, 22 is a combiner, 23 is light including information reflected by the combiner, 24 is a display image, 25 is light including information from a light emitting unit, and 26 is a display body. A transmissive liquid crystal display element, 27 is a light source composed of a cold cathode tube, 28 is a folding mirror, and 29 is a main body as a housing for holding and protecting these. Here, light emitted from the light source 27 passes through the transmissive liquid crystal display element 26, is reflected by the folding mirror 28, is irradiated to the combiner 22, is reflected and is reflected by the viewer 2 such as a driver.
1 is recognized.

On the other hand, recently, the use of a hologram as the above-mentioned combiner has attracted attention because of its simplicity as an optical element and the abundance of added functions. Since this holographic combiner can have not only a reflection function (diffraction function) but also a lens function, it can diffract optical information in the direction of the driver's field of view or use other optical systems such as lenses. Instead, a display image can be formed at an arbitrary position.

[0006]

Since the above HUD superimposes the display on the foreground ahead of the driver, it is necessary that the displayed image can be visually recognized without deteriorating the foreground luminance. Therefore, the light emitting means needs a light source that emits a luminance higher than the foreground luminance, while the combiner has a high transmittance,
A function of having high reflection performance or diffraction performance with respect to light including information from the light emitting means is required.

However, the foreground in an environment in which the HUD is used in a vehicle or the like varies from a very dark state at night to a very bright state during the day or a snowy surface in winter, and is displayed in such a state. In order to be able to visually recognize the light, a light emitting means capable of changing from low luminance to high luminance is required.
This high-luminance light emitting means is expensive, has a short life, is large in size, increases energy consumption and generates heat, so that it is necessary to take countermeasures. Thus, such a HUD has a large load on the light emitting means.

[0008] Even if it is said that the foreground luminance is not impaired,
If the display brightness is higher than the foreground brightness in a bright state during the daytime, the display will be dazzling and difficult to see. Therefore, a dark combiner that transmits the foreground appropriately has better contrast, and the display becomes easier to see. On the other hand, in a very dark state such as at night, a display with high contrast is displayed even if the display luminance is low. Therefore, a combiner with high transparency is better in terms of visibility of the foreground.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has a light-emitting means for generating a light beam, and a light-emitting means for reflecting and / or diffracting the light beam toward a viewer. And a combiner used in a head-up display device in which a display image formed by the combiner can be visually recognized in front of a viewer, wherein the transmittance of the combiner is determined by external light. It is intended to provide a combiner for a head-up display device characterized by changing.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic sectional view showing a basic configuration of an example of the combiner of the present invention. Here, 1 is a viewer such as a driver, 2 is a combiner, 3 is light containing information diffracted by the combiner, 4 is a display image, 5 is light containing information from the light emitting means, and 6 is a light emitting means side. A transparent glass plate, 7 is a hologram, 8 is an intermediate film, and 9 is a photochromic glass plate.

The combiner 2 is attached to the main body 29 in the same manner as the combiner 22 in the same manner as in the conventional example shown in FIG. The display image 4 is recognized by the viewer 1 such as a driver after being diffracted.

In FIG. 1, a hologram 7 is sealed in a laminated glass comprising a transparent glass plate 6 and a photochromic glass plate 9, and a hologram 7 is provided on the surface of the transparent glass plate 6.
And a photochromic glass plate 9 is laminated on the surface of the hologram 7 with a polyvinyl butyral interposition interlayer 8 interposed therebetween. This laminate is used as the combiner 2 and the photochromic glass plate 9 is held at a predetermined angle when used with the photochromic glass plate 9 facing away from the light emitting means.

The photochromic glass plate 9 has the characteristic of photochromism, which is a phenomenon in which it is darkened (colored or discolored) by light and reversibly fades (returns to the original colorless or colored state) when the irradiation of light is stopped. Things.

In the example of FIG. 1, the photochromic glass plate 9 is a phosphate-based photochromic glass (trade name: Reactol) manufactured by Chance-Pilkinton, which is practically used as a photochromic glass for glasses.
item Rapid) was used.

FIG. 2 is a diagram showing the spectral transmission characteristics of the photochromic glass plate 9 used in the example of FIG. 1. The solid line in FIG. This shows the characteristics in the case of (1).

An experiment was conducted with the combiner 2 shown in FIG. 1 and a head-up display device using the main body 29 shown in FIG. 3 mounted on a vehicle (hereinafter referred to as the present embodiment). And the foreground and display could be confirmed well, and in a bright environment in the daytime, the combiner was darkened so that a display with good contrast could be visually recognized. In addition, since the environment was bright, the foreground could be confirmed well through the combiner.

The hologram 7 in the example of FIG. 1 has a center diffraction wavelength of 543 nm, an incident angle of 25 degrees, a diffraction angle of 25 degrees, an efficiency of 90%, and a distance between the light emitting means and the combiner 2 in consideration of the emission line spectrum of the light emitting means. Is a reflection type hologram manufactured so as to have a magnification of 140 mm and a magnification of 4 times.

The light from the light emitting means passes through the transmissive liquid crystal display element, is reflected by the folding mirror, is irradiated to the combiner 2, is reflected and diffracted, and is recognized by a viewer such as a driver. At this time, the light 5 containing information directed to the combiner 2 is light that can change the photochromic characteristics of the photochromic glass plate 9, but most of the light is diffracted by the hologram 7 before reaching the photochromic glass plate 9. Further, since the energy is weaker than that of the external light, the light 5 for display hardly changes.

The hologram 7 in the example of FIG.
This is a Lippmann type volume / phase reflection hologram made of an acrylic photopolymer having a size of 70 μm, a length of 70 mm and a width of 70 mm.

The hologram of the combiner in the present invention has an area of several tens mm square to several hundred mm square, a thickness of several μm to several tens μm, has a light diffraction function, and is a Lippmann type hologram. A (reflection type) type is relatively easy to use, but other types called holograms can be widely used. Further, as the hologram material, various photosensitive materials such as other photopolymers, gelatin dichromate, and silver salts can be used.

The center diffraction wavelength of the hologram should be approximately equal to the peak wavelength of the light emitting means in order to increase the light use efficiency and to prevent the display light from causing a change due to the photochromism of the photochromic glass plate. preferable. Further, it is preferable that the band of the diffraction wavelength of the hologram includes the band of the wavelength of the light emitting means in order to prevent the display light from causing a change due to the photochromism of the photochromic glass plate.

The central diffraction wavelength of the hologram may be one formed by performing multiple exposure with light having different properties, or one obtained by superposing a plurality of holograms exposed with different light. If the color is multicolored, a hologram can be produced in accordance with the multicolor and multicolor display can be performed.

As described above, the specifications of the hologram in the combiner of the present invention are not limited to these, and various changes can be made depending on the device configuration and the characteristics of the light emitting means.

In the combiner of the present invention, the hologram is preferably used by being enclosed in a laminated glass in view of protection from external factors. The laminated glass is obtained by laminating and bonding a synthetic resin film such as a polyvinyl butyral film and a polyurethane film to glass including at least one photochromic glass plate. Examples of the form include a glass plate / synthetic resin film and glass. Plate / synthetic resin film / glass plate, glass plate / synthetic resin film / synthetic resin plate, and the like. The hologram may be sealed at the boundary between these glass plates or synthetic resin films. The glass plate on which the hologram is mounted is colored, or has an anti-reflection film, black-based ceramic film or heat ray reflection film on the surface,
A functional film such as a hard coat may be provided.

A glass plate is optimal for holding a hologram because it has little thermal deformation, but a resin plate is preferably used instead of a glass plate from the viewpoint of cost, weight reduction, and prevention of danger due to cracking. . In this case, in addition to sealing the hologram with an adhesive or the like between two resin plates formed of a resin plate having photochromism characteristics by an organic compound and another resin plate, It is preferable to seal the hologram with a material having photochromic characteristics in view of protection from external factors. Furthermore, a combination of a resin plate and a resin film may be used, and a functional film such as an anti-reflection film or a hard coat for protecting the resin plate may be formed on the surface of the resin plate similarly to the glass plate.

In the example of FIG. 1, the combiner 2 uses a hologram to obtain a function of enlarging a display image without using an optical system such as a lens. If not necessary, a half-mirror type combiner may be used, and it is also possible to add a curvature and an enlargement function to this. In the case of a half-mirror type combiner, a glass plate, a resin plate or a photochromic glass plate in which a reflective film is formed on the surface on the light emitting means side by sputtering or the like and a protective film is formed can be used. Also in this case, it is determined in consideration of the characteristics of the half mirror and the characteristics of the photochromism of the photochromic glass plate.

FIG. 1 shows a photochromic glass plate.
In addition to the phosphate glass as the example, silver halide glass containing borosilicate or colloidal silver halide particles may be used, but in consideration of practicality, coloring speed, and fading speed. Phosphate systems are preferred. Furthermore, many organic compounds having photochromic properties are known and can be used, but photochromic glass is more preferable in consideration of the use of the present invention.

The light emitting means of this embodiment includes a cold cathode tube,
DSTN LC as filter and transmissive liquid crystal display
A dot matrix type LCD called D was used, and the green emission line spectrum of the cold cathode fluorescent lamp was used. In addition, hot cathode tubes, tungsten lamps, halogen lamps,
Combining metal halide lamps, LEDs, LDs (laser diodes) with transmissive liquid crystal display elements,
It is also possible to use self-luminous type light emitting means such as a fluorescent display tube (VFD).

As a transmission type liquid crystal display device, DS
In addition to TN LCD, segment type VHC (Ve
It is also possible to use an LCD called a "ry High Contrast" LCD, or a dot matrix type thin film transistor (TFT) active matrix driving type LCD.

The display pattern is appropriately selected depending on the intended use, and includes a speed display, a vehicle warning light,
Examples include a blinker, a vehicle side light, a display related to a corner marker, character information such as traffic congestion information, and the like, and are not particularly limited as long as they are useful information. The observer is mainly a driver of the vehicle, and may include a passenger seat, other passengers, and all of them.

Further, if the main body is provided with a control means for automatically adjusting the brightness of the light emitting means based on the external light receiving sensor and the brightness of the surroundings and / or a control means for manually adjusting the brightness of the light emitting means, it is possible to provide an environment. A display image having a brightness corresponding to the brightness can be obtained, and the brightness can be adjusted manually. Therefore, the brightness can be adjusted according to the wishes of the individual, and the visibility is more improved.

In addition, as a method of obtaining a combiner whose transmittance is changed by external light, the transmittance of the combiner can be changed by electrical control using a liquid crystal or an electrochromic phenomenon. The use of the photochromism phenomenon as in the present invention is preferable in terms of cost and device configuration, since the configuration of the circuit network and the combiner itself becomes complicated.

In the optical path between the display and the combiner, there may be provided optical members such as a folding mirror, a concave mirror, a prism, a lens, a color filter and a polarizing element to prevent aberration of a display image and to prevent display. Various optical members may be provided to obtain a desired size of the image. Furthermore, aberration correction can be performed using two holograms by using other holograms.
Considering the size, a configuration as simple as possible as in the example of FIG. 1 is preferable.

The head-up display device using the combiner according to the present invention is preferably disposed near the windshield of the vehicle within a natural field of view of a driver or the like as a viewer, and is installed on the dashboard of the vehicle. However, the present invention is not particularly limited to this, and can be installed. Further, the present invention can be applied not only to a head-up display device for a vehicle but also to other display devices.

Further, a combiner may be formed on a windshield using a configuration similar to the configuration of the present invention, and used in a head-up display device.

[0036]

According to the present invention, the light emitting means is not overloaded, and can be used in both bright and dark environments.
A head-up display device that can provide easy-to-view display according to the environment in which it is used can be configured. In addition, if a photochromic material is used, it is not necessary to control the combiner electrically or mechanically at all, so that a head-up display device can be configured compactly, and a head-up display device with good display image quality can be mounted on a vehicle. it can.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing a basic configuration of an example of a combiner of the present invention.

FIG. 2 is a view showing a spectral transmission characteristic of a photochromic glass plate 9;

FIG. 3 is a conceptual diagram showing a configuration of a conventional separately placed HUD.

[Explanation of symbols]

 1, 21: Viewer 2, 22: Combiner 3, 23: Light including information reflected by the combiner 4, 24: Display image 5, 25: Light including information from light emitting means 6: Transparent glass plate 7: Hologram 8: Intermediate film 9: Photochromic glass plate 26: Transmission type liquid crystal display element 27: Light source 28: Folding mirror 29: Main body

Claims (4)

[Claims] 1. A light-emitting device for generating a light beam, and a combiner arranged to reflect and / or diffract the light beam toward a viewer, and view a display image formed by the combiner. What is claimed is: 1. A combiner for use in a head-up display device which can be visually recognized in front of a viewer, wherein a transmittance of the combiner is changed by external light. 2. A photochromic material is provided in said combiner, and said photochromic material
2. The combiner for a head-up display device according to claim 1, wherein the transmittance can be changed by external light. 3. A hologram is provided in said combiner, and said hologram is capable of reflecting and / or diffracting a light beam generated from a light emitting means toward a viewer. Or a combiner for a head-up display device according to 2. 4. A light emitting means for generating a light beam, and
At least the combiner according to any one of the above,
A head-up display device in which a display image formed by the combiner can be visually recognized in front of a viewer.