JPS61238015A - Display device for vehicle - Google Patents

Abstract

PURPOSE:To eliminate the deterioration of a display light emission body and to prolong the life by arranging a transparent glass plate at a Brewster angle to external incident light and providing a polarizing plate which cuts off polarized external light transmitted through the glass plate. CONSTITUTION:The polarizing plate 26 which polarizes the incident light in parallel to the paper surface is provided in parallel to the transparent plate 25 and the tilt angle of a windshield 1 is about 60 deg. to the horizontal surface. The transparent plate 25 has plural light shield plates 11 arranged in a transparent resin film 10 at constant intervals and transmits only light which is incident at theta (e.g. + or -<=10 deg.) to the perpendicular G to the film surface. The light from the sun 12 is separated into a component La perpendicular to the paper surface and a component Lb parallel to the paper surface, but when the refractive index of the windshield 1 is 1.5, the Brewster angle is about 57 deg., so the majority of the light transmitted through the windshield 1 becomes the polarized light component La and the component La passed through the windshield 1 is not transmitted through the polarizing plate 26 as long as the polarization direction of the polarizing plate 26 is set parallel to the paper surface, so that the life of the display body is never shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a display device for a vehicle that prevents deterioration in visibility of a driving information display image.

(Prior art) Driving information such as vehicle speed, mileage, inter-vehicle distance, remaining fuel level, or time has traditionally been displayed using a meter or clock installed on the instrument panel, but recently drivers have been unable to view this information. In order to avoid the need to take one's eyes away from the front field of view, a display device has been developed that focuses this driving information on the outside of the windshield in the front field of view so that it overlaps with the foreground in the field of view. (For example, Japanese Patent Laid-Open No. 57-182541) and is called a head amplifier display device.

FIG. 6 shows a schematic configuration of a conventional display device of this type, in which 1 is a windshield, 2 is a driving information display image projector provided inside an instrument pad, and 3 is a steering wheel. The projector 2 has a display body 2 such as a fluorescent display tube or a liquid crystal panel for displaying driving information inside the case 21.
2, a magnifying lens 23, and a total reflection mirror 24 are arranged, and 25 is a transparent plate.

4 is a driving information display image formed on the front outside of the windshield l, and 5 is a scene (foreground) in front of the vehicle.

The driver superimposes the driving information display image 4 on the foreground 5 in the forward field of view and then displays the I! You can see it at 6.

In such a display device, during the day, when the sun is at its southernmost position (southern position) and the sunlight is at its strongest,
Sunlight entering from directly above through the windshield 1 may pass through the transparent plate 25, be reflected by the total reflection mirror 24, and be focused on the driving information display body 22 by the magnifying lens 23. When the display surface of the display body 22 is irradiated with strong sunlight in this way, woff sheout occurs and the driving information display image 4 turns white, reducing the visibility of the display. This causes problems such as burning out the plastic color filter on the front surface of the display tube and significantly shortening the luminescent life of the fluorescent material in the fluorescent display tube.

(Objects and Structure of the Invention) The present invention has been made in view of the above points, and an object of the present invention is to prevent the visibility of the driving information display image from decreasing and the driving information display from becoming burnt due to sunlight entering through the windshield. In order to achieve this purpose, the windshield or the glass plate inside the windshield is arranged so as to form a pre-aster angle with respect to the incident light, and the polarized external light that has passed through the windshield or the glass plate is blocked. It was configured as follows.

(Example) The present invention will be explained below based on the drawings.

FIG. 1 shows a schematic configuration of an embodiment of a vehicle display device according to the present invention, and the same components as in FIG. 5 are indicated by the same reference numerals.

In this embodiment, a polarizing plate 26 that polarizes incident light parallel to the plane of the drawing is provided parallel to the transparent plate 25, and the angle of inclination of the windshield 1 is approximately 60° with respect to the horizontal plane. Note that here, 25 is a transmitting plate such as a light control film, and the light control film has a plurality of light shielding plates 11 arranged at regular intervals inside a transparent resin film 10, as the cross-sectional structure is shown in FIG. θ (for example, ±10
Only light incident within 100°F is allowed to pass through.

The light from the sun 12 is divided into a component perpendicular to the plane of the paper and a component parallel to the plane of the paper, but if the refractive index of the windshield 1 is 1.5, the Brewster angle is approximately 57°, so Most of the light passing through the windshield 1 becomes a polarized component La. Therefore, if the polarization direction of the polarizing plate 26 is set parallel to the paper surface, the component L1 that passes through the windshield 1
cannot pass through the polarizing plate 26, and only extremely weak light passes through.Even if this light is focused onto the display body 22 by the magnifying lens 23, the driving information display image 4 becomes white due to washout, reducing visibility. There is no risk of burning or burning out the plastic color filter on the front of the fluorescent display tube, which is the display, and the life of the display will not be shortened.In addition, when the sun is not in the south, the light is weak and has no effect. Although the amount of light is small, in order to reliably block light, it is recommended to use the light control film 25 to cant the light coming from an oblique direction.

FIG. 2 shows another embodiment of the vehicle display device according to the present invention, and this embodiment is an example in which the windshield is deeply sloped. In FIG. 0, the same reference numerals as in FIG. 1 indicate the same components.

In this embodiment, since the optical path of the driving information display light has a deep incident angle with respect to the windshield 1, the display body 22
Sunlight is concentrated only when the sun 12 is not directly above but at an oblique position as shown. In this embodiment as well, if the polarization direction of the polarizing plate 26 is selected to be the same as that shown in FIG. 1, and the direction of transmitted light of the transparent plate (light control film) 25 is set to 20''±10'', Light rays converging on the display body 22 and having an adverse effect can be prevented in the same way as in the embodiment of FIG. Incidentally, the cross-sectional structure of the light control film used as the transparent plate 25 in this embodiment is shown in FIG. The light control film shown in FIG. 3 is the same as the one in FIG. 6 except for the inclination of the light shielding plate 11. In this way, you can cant the light when the sun is in the south.

FIG. 4 shows still another embodiment of the vehicle display device according to the present invention. In this embodiment, the transparent glass 13 serving as the display surface is oriented with respect to the display optical axis so as not to depend on the inclined surface of the windshield. The transparent plate 25 is provided at an angle so that the transmission optical axis of the transparent plate 25 and the diagonal of the transparent glass 13 form a Brewster angle.

With this structure, most of the sunlight that passes through the windshield 1 is blocked by the transparent glass 13 and the polarizing plate 26, and only weak light reaches the display 22, so the display image of driving information becomes white. Therefore, the life of the display body 22 will not be shortened.

(Effects of the Invention) As explained above, in the present invention, the windshield or glass plate is arranged so as to form a Brewster's angle with respect to incident light from the outside, and the external light passing through the windshield is blocked. Since a polarizing means is provided, the amount of light that encounters the windshield and is focused on the driving information display is extremely small, causing the displayed image on the display to become whitish, reducing visibility or causing burnout of the display. This prevents deterioration of the light emitting part of the display body and extends its lifespan. Further, since it is possible to prevent external light from reaching the display body regardless of the inclination angle of the windshield, it is possible to assemble the display body as a subassembly in advance regardless of the type of vehicle.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of one embodiment of the vehicle display device according to the present invention, FIG. 2 is a schematic diagram of another embodiment of the vehicle display device according to the present invention, and FIG. FIG. 4 is a schematic diagram of still another embodiment of the vehicle display device according to the present invention; FIG. 5 is a cross-sectional view of the light control film used in the above embodiment;
FIG. 6 is a schematic diagram of an example of a conventional vehicle display device. 1... Windshield, 2... Projector, 22...
Driving information display body, 23... Magnifying lens, 24... Total reflection mirror, 25... Transparent plate, 26... Polarizing plate, 3
... Steering wheel, 4... Driving information display image, 5... Foreground, 13... Transparent glass.

Claims (1)

[Claims] A display device for a vehicle, comprising: a transparent glass plate arranged to form a Brewster's angle with respect to external incident light; and a polarizing plate that blocks polarized external light transmitted through the glass plate.