JPH0626436Y2 - Vehicle display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a display device for a vehicle, and more particularly to a display device that protects the display device against strong external light such as sunlight.

[Problems to be solved by conventional techniques and devices]

There is a vehicular display device having a structure shown in FIG. 6 which is conventionally called a head-up display. In the figure, a head-up display device 2 provided near a windshield 1 of a vehicle is provided with a lens 4 near a dashboard 3, and a display device 5 such as an LCD and a light source are provided on opposite surfaces thereof. 6 are provided.

In the configuration shown, the display pattern 7 obtained by the display device 5 is reflected on the surface of the windshield 1 through the lens 4 by the light source on the back surface thereof. When the driver sees the reflected light, the display image 8 can be viewed as a virtual image so as to overlap with the external scenery in front of the windshield 1.

However, in such a device, as shown in FIG. 7, sunlight is reflected by the lens 4 of the head-up display device.
When it is directly incident on the optical axis 9 of, the light flux passing through the lens 4 is focused on the focal point 10 and directly illuminates the display device 5 arranged in the vicinity. The heating temperature at this time reaches a high temperature in a short time. In particular, when strong light such as sunlight in midsummer enters, the display device 5 is easily destroyed.

Therefore, in order to deal with the above-mentioned problems, it is detected that sunlight is entering the lens unit, and the shutter plate provided between the lens and the display device blocks the sunlight. A device has been proposed.

FIG. 8 shows such a device, which includes a lens 4 and a display device 5.
A half mirror 11 is attached between the half mirror 11 and a part of the sunlight incident from the lens 4 is reflected by the half mirror to guide it onto the photodetection element 13.
Detects a luminous intensity above a predetermined level, the detection signal is input to the CPU 19 via the A / D converter 18,
The CPU 19 determines this, and the shutter drive control circuit 21
Then, the shutter drive circuit 20 is operated to close the shutter plate 12.

In the figure, 14 is a case, 15 is a blower drive circuit, 16 is a display device drive circuit, 17 is a temperature detection element, and 22 is A.
/ D converter, 23 is a blower drive control circuit, 24 is a light source lighting circuit, 26 is a ventilation port, and 27 is a blower.

However, in the above-mentioned device, since the half mirror is used in the projection optical path of the display pattern to guide the external light to the photodetector, the projection light of the display pattern formed in the liquid crystal display cell does not pass through the half mirror. There is a drawback in that the light is dimmed when it is transmitted, and finally the brightness of the display image reflected on the projection surface such as the windshield is reduced.

Therefore, it is conceivable to detect external light outside the projection optical path of the display image. However, there is a state where external light is incident on the lens but not on the photodetector. In this case, the shutter plate It will be opened and destroy the display device.

The present invention has been made in view of the above points, and an object of the present invention is to provide a vehicular display device capable of reliably protecting the display device without lowering the brightness of the display image.

[Means for solving problems]

In order to achieve the above object, the vehicular display device according to the present invention transmits light from a light source and projects the display pattern of the display device onto a projection surface such as a windshield through an optical system to display the display pattern. External light entering through the optical system is detected by a photodetector element, and in response to this detection, a shutter plate provided between the display device and the optical system blocks the external light entering the display device. In a vehicular display device, the photodetection element is fixed to a diffuser plate placed between a display device and a light source, and external light incident on the display device via an optical system is detected by the diffuser plate. The feature is that it is guided to and detected.

[Action]

In the above configuration, a shutter element provided between the display device and the optical system is driven to display a photodetection element that detects external light incident through the optical system in order to block external light incident on the display device. The light source is fixed to a diffuser plate placed between the device and the light source, and the external light incident on the display device via the optical system is guided to the photodetector element via the diffuser plate for detection. The display pattern of the display device, which is formed by transmitting the light from the display device and is projected on the projection surface such as the windshield through the optical system, is not dimmed.

[Example of device]

FIG. 1 is an explanatory view of the main part of the embodiment, and the temperature detecting element 17, converter, drive circuit, blower and the like shown in FIG. 8 are omitted.

The projection device is housed in an L-shaped case 14, and the display pattern of the display device is reflected by a total reflection mirror 28 and is projected through a lens 4 onto a projection surface such as a windshield.

A liquid crystal display cell in which liquid crystal is enclosed in two glass plates is used as the display device 5, and its display pattern is projected forward by light transmitted through the liquid crystal display cell from a light source 6 at the rear.

Between the display device 5 and the light source 6, a diffuser plate 29 for correcting uneven brightness of light from the light source 6 is arranged.
The light that has passed through the diffusion plate 29 and is sufficiently diffused illuminates the display device 5 from behind with uniform brightness. As the diffusion plate 29, a transparent glass plate whose surface is formed into a fine uneven surface is used.

As shown in an enlarged view in FIG. 2, the photo-detecting element 13 is fixed to one end surface of the diffusion plate 29 with an adhesive 30 such as epoxy. The light receiving surface of the photodetector 13 is arranged with the end face of the diffuser plate 29 facing, and part of the light incident on the diffuser plate 29 is repeatedly reflected inside and then enters the photodetector device 13 from the end face.

The photo-detecting element 13 is similar to the conventional device shown in FIG.
When the external light such as sunlight is incident on the display device 5 via the lens 4 and the mirror 28 and the level of the light becomes equal to or higher than the level of the light from the light source 6, the CPU
When the determination is made by 19, the drive circuit is controlled to control the shutter plate 12
Is rotated to cover the entire surface of the display device 5 and block sunlight.

In general, the level of external light such as sunlight is much higher than the level of light from the light source 6, so that the external incident light is not detected directly on the projection optical path and propagates while being reflected in the diffusion plate 29 as described above. Even if the emitted light is detected, malfunction does not occur.

FIGS. 3, 4 and 5 are other embodiments of the present invention. Third
In the example shown in the figure, a diffuser plate 29 having a triangular cross section is used, and in FIG. 4, the diffuser plate 29 is formed to be somewhat larger than the glass plate of the display device 5, and a hole 29a is formed in this extended portion.
The light detecting element 13 is embedded in the hole 29a, and in FIG. 5, the light receiving surface of the light detecting element 13 is directly glued without forming holes in the extension of the diffusion plate 29 of FIG. It is fixed.

In any of the above-described embodiments, the external light reaches the photodetecting element 13 through the inside of the diffuser plate 29, and the shutter plate can be driven by detecting this. The mounting position and method of the photodetecting element 13 with respect to the diffusion plate can be appropriately selected in consideration of mounting space, mounting workability, mounting strength, detection accuracy, and the like.

[Effect of device]

As described above, according to the present invention, in order to correct the brightness unevenness of the light of the light source incident on the display device, the light detecting element is fixed to the diffuser plate installed between the light source and the display device. It is designed to detect external light that reaches through.

Therefore, since a half mirror for extracting external light is not used in the projection optical path of the display pattern, the projection light is not dimmed, the brightness of the display image can be maintained high, and the number of parts is reduced. Therefore, the cost can be reduced, which is advantageous for saving the space of the device.

Furthermore, since the unevenness of the brightness of the light that has passed through the diffuser plate is corrected, the detection accuracy of the external light by the photodetector is good and the performance can be stabilized.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of essential parts of an embodiment of the present invention, FIG. 2 is an enlarged side view of essential parts of the embodiment, and FIGS. 3, 4 and 5 are side views of essential parts of other embodiments, and FIG. FIG. 7 is a schematic configuration diagram of a conventional vehicle head-up display device, FIG. 7 is an explanatory diagram of problems of the conventional device, and FIG. 8 is a configuration diagram of essential parts of a comparative example with the present invention. 1 ... Windshield, 2 ... Head-up display device, 4 ... Lens, 5 ... Display device, 6 ... Light source, 7 ... Display pattern, 8 ... Display image, 12 ... Shutter plate, 13 ... Photodetection element, 29 ... Diffuser plate .

Claims (1)

[Scope of utility model registration request] 1. A light detecting element which transmits light from a light source and projects a display pattern of a display device onto a projection surface of a windshield or the like via an optical system to display the light and external light incident through the optical system. The shutter plate provided between the display device and the optical system according to this detection,
In a vehicular display device adapted to block external light incident on a display device, the photo-detecting element is fixed to a diffuser plate placed between the display device and a light source, and is placed on the display device via an optical system. A vehicle display device, characterized in that incident external light is guided to a photodetector through a diffusion plate and detected.