JPH05330362A - Display unit for vehicle - Google Patents

Abstract

PURPOSE:To eliminate any double image due to a display lift and enhance the quality of display character and improve the sightability by installing a polar screen, whose phase is mutually shifted as far as 90 degrees to both sides of an-optical path and a half mirror, in this optical path lying between the half mirror and a light projector unit. CONSTITUTION:A first polar screen 21 is installed in an optical path lying between a light projector unit 1 and a half mirror 23. A second polar screen 22 whose phase is shifted as far as 90 degrees with the first polar screen 21 is installed in space between this half mirror 23 and a windshield 4 of a car. With this constitution, a display light reflected out of a mirror 20 is unable to pass through the second polar screen 22 in an inner part of the half mirror 23 and it can be only reflected in consequence, so that any double image is not produced at all.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle display device,
In particular, the present invention relates to a so-called head-up display (HUD) display device for a vehicle, in which display light from a light projecting unit is projected on a windshield of a vehicle to form a virtual image of the display light in front of the windshield. Is.

[0002]

2. Description of the Related Art FIG. 3 schematically shows a vehicle display device which is well known in the prior art.
Is composed of a backlight 2 and a liquid crystal display (LCD) 3.
The display light output from the device is controlled by a control unit (not shown), passes through the opaque portion and the transparent portion of the transparent portion appearing on the liquid crystal display 3, and is projected as projection light 13 on the windshield (front glass) 4. To be done.

The display light projected on the windshield 4 is reflected by the windshield 4 and reaches the naked eye 5 of the driver. In this case, the driver forms a virtual image 30 in front of the windshield 4 as shown in the figure. It will be visually recognized by the naked eye 5 of the driver, and the driver will recognize the current vehicle speed as 88 km / h indicated by the virtual image 30, for example.

[0004]

When the display light from the light projecting unit 1 is projected onto the windshield 4 as described above, the display light from the light projecting unit 1 is projected onto the windshield 4 as shown in FIG. When the virtual image light 11 as shown in the figure is received by the naked eye 5 and is recognized by the naked eye 5, the double virtual image light 12 shown by the dotted line in FIG. When it is received and recognized, it occurs.

Therefore, in such a case, the segment 31 as shown in FIG.
Each alpha numerical constituted by is to be recognized by the driver as a clear virtual image 30 shown by a solid line and a double virtual image 30 'shown by a dotted line, which is a factor that hinders the visibility of the display image.

Further, the sunlight 14 (solid line) incident from the outside of the windshield 4 is reflected by the mirror 20 and reaches the light projecting unit 1, which causes the light projecting unit 1 to become hot. However, there is a problem in that the function is impaired, which causes a decrease in life and causes a so-called wash-out phenomenon in which a display image becomes relatively thin.

Therefore, according to the present invention, the display light from the light projecting unit is projected on the windshield of the vehicle to form a virtual image of the display light in front of the windshield. It is an object of the present invention to eliminate the double image of (1) and to eliminate the adverse effect of external sunlight or the like on the light projecting unit.

[0008]

To achieve the above object, a vehicle display device according to the present invention comprises a light projecting unit,
A mirror for reflecting the display light from the light projecting unit, a half mirror for reflecting the reflected light from the mirror toward the driver and transmitting the light outside the vehicle, and a mirror between the light projecting unit and the half mirror. A first polarization filter provided in the optical path and provided between the half mirror and the windshield of the vehicle and having a phase of 90 ° with respect to the first polarization filter.
And a second polarizing filter that is arranged with a shift.

[0009]

In the vehicle display device according to the present invention, the display light output from the light projecting unit is reflected by the mirror and further reflected by the half mirror on the windshield side so that it can be visually recognized by the driver. ..

At this time, a first polarizing filter is provided in the optical path of the display light between the light projecting unit and the half mirror, and a second polarizing filter is further provided between the half mirror and the windshield. In addition, since the phases of these two polarization filters are deviated by 90 °, the display light from the light projecting unit passes through the mirror and reaches the half mirror before passing through the first polarization filter. It is converted to linearly polarized light.

Then, the display light is reflected again by the half mirror, but at this time, the second polarization filter inside the half mirror is installed with a 90 ° phase shift with respect to the first polarization filter. Therefore, the display light reflected from the mirror cannot pass through the second polarization filter inside the half mirror and is only reflected, so that the double image as shown in FIG. 4 does not occur.

Similarly, sunlight incident from the outside of the windshield is converted into linearly polarized light in a fixed direction by a second polarizing filter provided between the windshield and the half mirror, and then the mirror. The second polarizing filter tries to pass through the second polarizing filter while being reflected by the first projecting unit and is incident on the light projecting unit. However, since the second polarizing filter is arranged 90 degrees out of phase with the first polarizing filter, The second polarizing filter cannot pass through, so that it can be prevented from entering the light projecting unit.

[0013]

1 shows an embodiment of a vehicular display device according to the present invention. The difference between this embodiment and the conventional example shown in FIG. Polarizing filter 2
1 is provided, and the second polarizing filter 22 is provided on the surface of the portion which is reflected by the windshield 4, and the half mirror 23 is provided on the surface thereof.

In the operation of this embodiment, the display light emitted from the backlight 2 of the light projecting unit 1 passes through the transparent portion of the liquid crystal display 3 and is sent to the mirror 20 as projection light 13.

In the mirror 20, since the display light from the light projecting unit 1 of the projection light 13 is natural light when passing through the polarization filter 21 provided on the surface of the mirror 20, the polarization filter 21 provided on the surface of the mirror 20. Is converted into a linearly polarized light in a fixed direction, for example, a vertical direction, and reflected.

The linearly polarized light reflected from the mirror 20 is reflected by the half mirror 23 and reaches the naked eye 5 of the driver, and also tries to enter the half mirror 23.
Since the polarization filter 22 provided between the half mirror 23 and the windshield 4 is placed 90 degrees out of phase with the polarization filter 21 provided on the surface of the mirror 20, the linear polarization set by the polarization filter 22 is set. All the display light incident on the half mirror 23, which cannot pass through at a right angle to the direction of, is reflected and sent to the naked eye 5 of the driver.

Therefore, the windshield 4 prevents the display light from being visually recognized as a double image as shown in FIG.

Similarly, when the sunlight 14 is incident from the outside of the windshield 4 as shown in the figure, the polarization filter 22 once converts it into linearly polarized light in a certain direction and sends it to the mirror 20. Also in 20, the polarization filter 21 provided on the surface has a phase difference of 9
Since they are arranged 0 ° apart from each other, they cannot be reflected and are prevented from entering the light projecting unit 1.

FIG. 2 shows another embodiment of the vehicular display device according to the present invention. The difference between this embodiment and the embodiment of FIG. 1 is that the polarizing filter 21 is projected not on the surface of the mirror 20. If the polarizing filters 21 and 22 are provided in the output section of the optical unit 1 and are arranged in a 90 ° phase-shifted relationship, a double image when reflected by the windshield 4 in the same manner as in FIG. Windshield 4
The sunlight from the outside can also be blocked at the entrance of the light projecting unit 1.

The phase shifts of the polarization filters 21 and 22 may be arranged in a physically orthogonal relationship as shown in the figure.

[0021]

As described above, according to the vehicle display device of the present invention, the display light from the light projecting unit is reflected by the mirror and the half mirror on the windshield side to be visually recognized. Since a polarizing filter having a phase difference of 90 ° is provided in the optical path between the projector and the light projecting unit and on the side of the half mirror, it is possible to eliminate the double image due to the display light and to enhance the quality of the displayed characters. As a result, the visibility can be improved and the projection image can be prevented from being seen out due to sunlight.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing another embodiment of a vehicle display device according to the present invention.

FIG. 2 is a configuration diagram showing another embodiment of the vehicular display device according to the present invention.

FIG. 3 is a configuration diagram showing a conventional example.

FIG. 4 is a diagram illustrating a case where display images of respective alphanumerics on a liquid crystal display are doubled in a conventional example.

[Explanation of symbols]

 1 Projection Unit 2 Backlight 3 Liquid Crystal Display (LCD) 4 Windshield 5 Eyes 20 Mirror 21 First Polarization Filter 22 Second Polarization Filter 23 Half Mirror 30 Display Image In the drawings, the same reference numerals indicate the same or corresponding parts. .

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kunio Ogame Inoue Kunio 3-25-1 Tonomachi, Kawasaki-ku, Kanagawa Prefecture Isuzu Motors Limited Kawasaki Plant (72) Naomasa Sugiyama 3-chome, Tonomachi, Kawasaki-ku, Kanagawa Prefecture No. 25-1 Isuzu Motors Co., Ltd. Kawasaki Plant (72) Inventor Shinro Echida 3-25-1 Tonomachi, Kawasaki-ku, Kawasaki City, Kanagawa Isuzu Motors Co., Ltd. Kawasaki Plant

Claims (1)

[Claims] 1. A light projecting unit, a mirror for reflecting display light from the light projecting unit, a half mirror for reflecting reflected light from the mirror toward a driver and transmitting outside light, and the projecting unit. A first polarization filter provided in the optical path between the optical unit and the half mirror and a phase difference from the first polarization filter provided between the half mirror and the windshield of the vehicle by 90 °. A second polarizing filter that is disposed, and a vehicle display device.