JPH0299427A - Head up display unit - Google Patents

Abstract

PURPOSE:To improve its visibility, by providing an angle selecting permeable film on the light incident side of a semi-transparent combiner disposed on the front glass of a vehicle, the angle selecting permeable film which allows light incident thereon from a specific direction to pass therethrough and which scatters or cuts off light incident thereon from other directions. CONSTITUTION:A display apparatus 1 comprising a fluorescent character display tube or liquid crystal for displaying images providing information on the condi tion of vehicle running such as vehicle speed, engine speed, etc., and an aberra tion correcting first hologram 2 disposed within the dashboard of a vehicle. A second hologram forming an optical system together with the first hologram and used as a combiner is provided on that portion of a front glass 6, 6 on which the image are projected, while the second hologram is laid on an angle selecting permeable film 5 for covering the main outer face of the second holo gram 4. The angle selecting permeable film 5 is formed using a polymer film having the property of allowing light incident thereon from a specific direction, e.g., at an incident angle of less than -50 deg. to pass therethrough and also scatter ing light incident thereon at an incident angle of more than -50 deg..

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a head-up display device that projects a display image of driving information within the forward field of view through the windshield of a vehicle.

[Conventional technology]

In recent years, from the standpoint of improving safety when driving vehicles.

Optical technology is used to display information on the inside of the windshield so that the driver can recognize driving information such as vehicle speed, which is normally displayed on instruments located in the instrument panel, without taking their eyes away from the front view. A head-up display device is being considered that displays driving information overlaid on the front field of view by projecting the driving information display image onto a transparent reflective plate called a combiner that is arranged.

As a conventional example of such a head-up display device, one that utilizes holography technology, for example, has been proposed (Japanese Patent Application Laid-open No. 35416/1983). In this device, as shown in FIG. 5, a hologram 11 made of a semi-transmissive diffraction member used as a combiner is embedded as a laminate in a windshield 12 having a laminated structure, and a hologram 11 made of a semi-transmissive diffraction member used as a combiner is embedded as a laminate in a windshield 12, and a hologram 11 is placed inside a dash board or the like. A display image of driving information is projected onto the hologram 11 from a display device via an optical system. The hologram 11 is a record of interference fringes of coherent light a and beam irradiated from a predetermined direction as shown by the arrow in the figure, and the display is projected onto the hologram 11 from the direction a through an optical system. The light constituting the image is diffracted and reflected in direction b, which is the driver's line of sight, and
Enter 13. As a result, the driving sound can be seen as a virtual image of the display image formed on the outside of the windshield 12 superimposed on the front view.

Another conventional example is to place a combiner made of a transflective member inside the windshield, and project the display image from the display onto the combiner through an optical system made of a reflective member having a lens function. By doing so, it is possible to form a virtual image of the display image in the front field of view as in the conventional example (Japanese Patent Application Laid-Open No. 62-31531), or to directly display the display image from the display placed on the dash board on the combiner. A system has been proposed in which a mirror image of the displayed image is projected onto a combiner (Japanese Patent Application Laid-Open No. 139728/1982).

[Problems that the invention attempts to solve]

In the conventional example described in -1-, the reflectance of the displayed image is increased by a combiner in order to make the displayed image appear brighter. For this reason, in the above-mentioned holography system, as shown in FIG. The light is diffracted and reflected by the stripes and projected toward an oncoming vehicle, causing problems such as dazzling the driver of the oncoming vehicle. Further, in the other conventional examples described above, similar problems arise due to increasing the reflectance of the transflective member used as a combiner.

Furthermore, in the holographic recording optical system, the hologram dry plate constituting the hologram 11, as shown in FIG. Interference fringes due to ' and b' are also recorded.

Therefore, as shown in Figure 8, the windshield 1 is
2, the light corresponding to the optical path of the light a' is transmitted to the hologram 11.
When incident on the hologram 11, the lights a, b,
b' is reproduced, and some of the light enters the driver's eyes as noise light. Since the light beam reproduced at this time is a transmission hologram (Fresnel hologram), it becomes rainbow-colored noise light6.Also, the light incident on the windshield 12 from outside the vehicle once passes through the hologram 11 as shown in FIG. After passing through, it may be reflected by the back surface of the windshield 120 on the vehicle interior side and enter the hologram 11 again on the same or almost the same optical path as the light a in FIG. 6 (indicated by a broken line in FIG. 9). In this case, the light reflected from the back of the glass is diffracted and reflected by the hologram 11 in the same direction as the light shown in FIG. 7, and enters the driver's eyes as noise light. This noise light is a reflection hologram (Lippmann hologram). Furthermore, depending on the configuration of the device, light from outside the vehicle may enter other holograms that make up the optical system, and this incident light may generate noise light as described above from the hologram toward the display. It may also disturb the displayed image.

In this way, with conventional holographic devices.

Since rainbow-colored or monochromatic noise light is generated, problems arise in that not only the visibility of the displayed image is reduced, but also the driver's forward vision is obstructed.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a head-up display device that suppresses the generation of noise light for oncoming vehicles and drivers, secures forward visibility, and improves the visibility of displayed images. It is something to do.

[Means for solving problems]

In order to solve problem L, the present invention provides a display image such as driving information displayed on a display device using an optical system including a translucent combiner disposed on or near the windshield of the vehicle. In a head-up display device that optically displays the display image superimposed on the driver's front field of vision by projecting an image onto the driver's front view, the head-up display device transmits light incident from a specific direction and scatters or scatters light incident from other directions. An angle-selective transmission film for blocking is provided on the external light incident side of the combiner or the optical element constituting the optical system.

[Effect]

In the present invention configured as described above, light incident on the windshield from outside the vehicle enters the combiner via the angle-selective transmission film. This angle-selective transmission film transmits incident light from a specific direction (light in the direction of the driver's line of sight), and scatters or blocks incident light from other directions to prevent it from entering the combiner.

That is, the direction of incidence of light incident on the combiner, which causes the generation of noise light as described above, is determined by the slope of the windshield, the installation position of the combiner, etc. When installed, the incident light that generates the noise light is transferred to the combiner (
That is, the angle of incidence in the elevation direction relative to the windshield is approximately in the range of 150 degrees to 40 degrees, and the direction of the driver's line of sight with respect to the combiner is at an angle lower than the above angle range. Therefore, by selectively transmitting incident light from outside the vehicle and making it enter the combiner using the angle-selective transmission film as described above, external visibility through the combiner is secured, and light that causes noise light is prevented from entering the combiner. It suppresses the incident.

Similarly, even if the above-mentioned noise light is generated toward the display device from other optical elements constituting the optical system due to the configuration of the device, the light that causes the generation of noise light may enter the optical element. is suppressed.

〔Example〕

FIG. 1 is a diagram showing the configuration of an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a display device for displaying an image of driving information such as vehicle speed and engine speed, and is made of a fluorescent display tube, liquid crystal, or the like.

Reference numeral 2 denotes a first hologram for aberration correction, which is an element of an optical system for projecting a display image into the front field of view. The first hologram 2 has glasses 3, 3 for preventing deterioration adhered to both main surfaces thereof with an optical adhesive or the like, and is placed together with the display 1 in a dash board of a vehicle. A second hologram 4 constitutes an optical system together with the first hologram 2 and is used as a combiner. Reference numeral 5 denotes an angle-selective transmission film that covers the main surface of the second hologram 4 on the outside of the vehicle, and has a laminated structure when superimposed on the second hologram 4, and is positioned at the display image projection position in the windshield 6.6. It is sandwiched. The angle-selective transmission film 5 transmits light from a specific direction and blocks light from other directions. As shown in FIG. 2, a polymer film is used which has the property of transmitting light with an incident angle of 150° or less and scattering light with an incident angle of 150° or more.

Note that 7 is an adhesive such as polyvinyl butyral for bonding the windshield 6.6.

In the above configuration, the light constituting the display image irradiated from the first display 1 is first projected onto the first hologram 2, diffracted and reflected there toward the second hologram 4, and then further diffracted by the second hologram 4. It is reflected and enters the driver's eyes 8. As a result, the driver can visually recognize the virtual image of the display image from the display device 1 formed on the outside of the windshield 6.

Here, the angle-selective transmitting film 5 selects the incident light in the area where the incident angle including the driver's line of sight direction is 150' or less, as described above, from among the light incident on the second hologram 4, which is a combiner, from outside the vehicle. The second hologram 4 is prevented from entering the second hologram 4 by scattering incident light in an area of 150 degrees or more, including incident light that causes noise light. There is. Therefore, the forward visibility through the second hologram 4 and the angle-selective transmission film 5 is secured, and the driver is protected from noise light on the oncoming vehicle due to light from above, such as sunlight, and to the driver due to incident light from a specific optical path. The generation of iridescent or monochromatic noise light is significantly reduced, which improves the visibility of the displayed image and prevents forward visibility from being obstructed, and also does not dazzle oncoming vehicles. .

In addition to the polymer film in the above embodiment, the angle-selective transmission film 5 may be an angle-selective transmission film that has a built-in light-shielding plate with a honeycomb structure or a louver structure, or a crystal structure that reflects or absorbs light from a specific direction. You can use things with gender.

:The angle-selective transmission film 5 does not necessarily need to be installed in alignment with the second hologram 4 used as a combiner as in the above embodiment, and as shown in FIG.
The above implementation can also be carried out by arranging only the angle-selective transmission film 5 at the corresponding position in the windshield 6 in a device in which the hologram 4 is held between deterioration prevention glasses 3.3 and placed on the dash board of the vehicle. The same effect as in the example can be obtained. However, in this case, the characteristics of the angle-selective transmission film 5 must be determined in consideration of the inclination of the windshield 6, the installation angle and characteristics of the second porogram 4, etc.

Also, as shown in FIG. 4, a first hologram 2.

In other embodiments in which a combiner 9 using a vapor deposited film (half mirror) or surface reflection is combined, the same effect can be obtained by providing the angle selective transmission film 5. This angle-selective transmission film 5 allows information from the first hologram 2 to pass therethrough, and prevents disturbance light (into the hologram 2) that generates noise light from entering. This angle-selective transmission film 5 can prevent disturbance light such as sunlight from entering the hologram 2, thereby preventing noise light generated when external light reflected by the hologram 2 illuminates the display. can. .

Although an example of a holography type device has been described above, in a device that projects a display image using an optical system composed of a reflective member, the outside of the combiner made of a semi-transparent reflective member can be used in the same way as in the above embodiment. By arranging the angle-selective transmission film on the light incident side, the same effects as in the embodiments described above can be obtained, such as preventing noise light from reaching oncoming vehicles and improving the visibility of the displayed image.

〔effect〕

As described above, the present invention provides a head-up display device in which incident light in a specific direction, that is, in the direction of the driver's line of sight, is transmitted through the external light incident side of the combiner.
In addition, by providing an angle-selective transmission film that scatters or blocks incident light from other directions, the driver's forward visibility is secured. Since the light entering the combiner can be suppressed, the driver's forward view is not obstructed, the visibility of the displayed image is improved, oncoming vehicles are not dazzled, and the angle can be selected. By suppressing unnecessary external light from entering the optical elements that make up the optical system with a transparent film, it is possible to prevent the generation of noise light on the display, resulting in effects such as not disturbing the displayed image. play.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a main part of an embodiment of the present invention, and FIG. 2 is a diagram showing characteristics of an angle-selective transmission membrane in an embodiment of the present invention.
FIGS. 3 and 4 are sectional views of main parts of other embodiments of the present invention, and FIGS. 5 to 9 are diagrams showing the operation of a conventional head-up display device. 1・・・・・・Display device. 2......First hologram, 3...
...Glass. 4... Second hologram. 5...Angle-selective permeation membrane. 6......windshield. 7・・・・・・Adhesive.

Claims (1)

[Claims] By projecting a display image such as driving information displayed on a display onto a semi-transparent combiner placed on or near the windshield of the vehicle, In a head-up display device that optically displays the display image superimposed on the driver's front field of vision, an angle-selective transmission film that transmits light incident from a specific direction and scatters or blocks light incident from other directions is provided. A head-up display device, characterized in that it is provided on an external light incident side of an optical element constituting the combiner or the optical system.