JPH03200426A - Indication device for vehicle - Google Patents

Abstract

PURPOSE:To prevent reversal incidence of the sunlight by reflecting indication light to the side of a driver at a specific angle with a holographic lens attached to and provided on a projection member as well as entering the indication light at a specific angle against the projection member of a front glass or others. CONSTITUTION:A drive informations such as rotating speed of a car or others is radiated as an indication light from a liquid crystal indication element 6 as well as indicated with instruments in an inner panel 3, and it enters at an incident angle theta1 of more than a critical angle thetaB to a holographic lens attached to and provided on a front glass 1 through a convex lens of a light passage theta1. Thereafter, it is reflected in the inside rear direction at a reflection angle theta2 which is smaller than the incident angle theta1 so that a driver 11 can see an indication image 13 and a scenery 14 overlapped in the outside front direction of the front glass 1. On the other hand, the sunlight 15 on an extensive line of an indication light 8 is made incident the critical angle theta1 which is larger than the critical angle thetaB against the front glass 1 and is totally reflected at the specific reflection angle theta1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vehicle display device called a so-called head-up display.

[Conventional technology]

Traditionally, driving information such as vehicle speed, mileage, remaining fuel level, or time was displayed on gauges installed on the instrument panel, but recently drivers have had to view this information by viewing it from the front view. (By projecting this driving information onto a projection member in front of the driver, such as the windshield, so that the driver does not have to move his/her line of sight, the displayed image is formed in the front field of view outside the windshield, and the scenery within the field of view is A display device was developed that overlapped with the
For example, it is disclosed in Japanese Utility Model Application Publication No. 63-81721.

[Problem to be solved by the invention]

In the above conventional technology, display light as driving information emitted from a display body passes through an optical path and reaches a convex lens.
It is configured so that it passes through this convex lens and is emitted toward a projection member, for example, a windshield, and a display image is formed in front of the outside of the windshield.
When sunlight enters the light path inside the vehicle from the windshield, the sunlight may pass through the convex lens and enter the light path back into the light path to reach the display. is projected onto the surface of the display and washes out, reducing visibility. At the same time, sunlight is focused on the display due to the condensing action of the convex lens, and the display is heated by the infrared rays of sunlight. The problem was that it deteriorated.

In order to solve this problem, an optical filter is provided in the optical path between the windshield and the optical system to limit the angle of incidence of sunlight, and the sunlight is projected onto a part of the display object through this optical filter. Japanese Patent Application Laid-Open No. 1983-1980 discloses a device in which the angle of incidence of sunlight is limited to an extremely narrow area and is absorbed by the light absorption means by providing a light absorption means for absorbing sunlight.
This method has been proposed in Japanese Patent No. 205570, but since this method limits the angle of incidence of sunlight that is reversely incident on the optical path and absorbs it, the structure tends to be complicated.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a display device for a vehicle that can prevent sunlight from entering the optical path of display light by totally reflecting the sunlight directed toward the optical path of display light by a projection member.

[Means to solve the problem]

In the vehicle display device of the present invention, the angle of the optical path of the display light is set so that the angle of incidence of the display light on the projection member is equal to or larger than the critical angle, and the angle of the optical path of the display light is set on the projection member so that the angle of incidence of the display light is smaller than the angle of incidence. It is equipped with a holographic ink lens that records information that is reflected back toward the driver at different angles.

[Function] With the above configuration, sunlight directed toward the optical path of the display light is totally reflected outward by the projection member, and reverse entry into the optical path is prevented. Further, display light emitted to the projection member through the optical path at an incident angle equal to or greater than the critical angle is reflected by the holographic ink lens and guided to the driving side.

〔Example〕

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows an embodiment of the present invention, in which reference numeral 1 denotes a windshield of a vehicle 2, which serves as a projection member for projecting a display image to be described later. Reference numeral 3 denotes an instrument panel made of a non-light-transmitting material, and an opening window 4 communicating with a projector, which will be described later, is provided on the upper surface of the instrument panel. 5 is a projector provided in the instrument panel 3;
This projector 5 has a transmissive liquid crystal display element 6 that is a display device that displays driving information such as vehicle speed, time, etc. in numbers and pictures.
and a light source 7 provided on the rear surface of this liquid crystal display element 6,
A convex lens 9 guides the display light 8 of the liquid crystal display element 6 from the light source 7 to the windshield 1 through the aperture window 4.
It has an optical path 10 from the liquid crystal display element 6 to the convex lens 9. Further, the projector 5 is provided with the angle of the optical path 10 set so that the incident angle θ1 of the display light 8 with respect to the windshield 1 is equal to or greater than a critical angle. In this case, the critical angle θ is determined by the following equation, and si
nθB 2 In the formula, n is the absolute refractive index of the windshield 1, and if n=1.52, the low field angle θ! 1', 41°, and the incident angle θ1 of the display light 8 satisfies θ1≧41°.

A combiner (not shown) is formed as necessary on the inner or outer surface of the windshield 1 to reflect the display light 8 by a method such as vapor deposition or coating. A holographic lens 12 is provided on the user 11 side.

The holographic lens 12 is made of dichromate gelatin and reflects the display light 8 incident on the windshield 1 at an angle θ greater than or equal to the critical angle 08 at an incident angle θ and a smaller reflection angle θ2 toward the driver 11. Information for guiding the display light 8 is recorded. 13 is a display image formed on the front outside of the windshield 1, 14 is a landscape, and 15 is sunlight.

For example, the vehicle speed detected by the vehicle speed sensor is displayed by instruments in the instrument panel 3, and is emitted as display light 8 in the form of numbers from the liquid crystal display element 6. It is radiated through the passage 10 through the convex lens 9 toward the holographic lens 12 of the windshield 1 at an incident angle θ greater than or equal to the critical angle 08, and is reflected at the holographic lens 12 at a reflection angle θ2 smaller than the incident angle θ1 on the driver's side. As a result, the driver 11 sees a display image 1 on the outside front of the windshield 1.
3 and scenery 14 can be seen superimposed.

On the other hand, sunlight 15 heading toward the optical path 10 of the projector 5
In other words, the sunlight 15 that is an extension of the display light 8 heading toward the windshield 1 attempts to enter the windshield l at an incident angle θ1 that is greater than the critical angle 68, so it is directed outward at the reflection angle θ1 on the outer surface of the windshield 1. It is totally reflected towards the direction. Therefore, reverse incidence of sunlight 15 into the optical path 10 of the projector 5 is prevented, and the problem of reduced visibility due to washout and heating of the display body due to concentration of sunlight can be reliably solved. .

In this way, in this embodiment, the angle of the optical path 10 is set so that the incident angle θ1 of the display light 8 with respect to the windshield l, which is the projection member, is equal to or larger than the low field angle, and the angle of the display light 8 is set so that the incident angle θ1 is smaller than the incident angle θ1. By providing a holographic ink lens 12 on the windshield 1 in which information for reflecting the light toward the driver 11 at an angle θ2 is recorded, the display light 8 is reflected toward the driver 11 through the optical path 10 while heading toward the optical path 10. Since the sunlight 15 is totally reflected outward on the surface of the windshield 1, it is possible to prevent the sunlight 15 from entering the optical path 10,
Deterioration in visibility caused by sunlight 15 entering the optical path 10 in the opposite direction and deterioration of the display body due to heat can be reliably prevented.

Note that the present invention is not limited to the above-mentioned embodiments, and various modifications can be made within the scope of the gist of the present invention. For example, the incident angle θ of the display light may be arbitrarily set to an angle greater than or equal to the critical angle, and the information to be recorded holographically is determined from the incident angle θ1 corresponding to the incident angle θ of the display light and the position of the driver. The display light may be appropriately set so as to reflect the display light at a small arbitrary reflection angle θ2.

〔Effect of the invention〕

In the present invention, the angle of the optical path of the display light is set so that the angle of incidence of the display light on the projection member is equal to or greater than a critical angle, and the display light is directed to the driver side at an angle smaller than the incidence angle on the projection member. By providing a holographic ink lens with information to be reflected recorded thereon, sunlight directed toward the optical path of display light is totally reflected outward by the projection member, and solar light can be prevented from entering the optical path backwards. Display devices can be provided.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram showing an embodiment of the present invention. 1-~ Windshield (projection member) 6-Liquid crystal display element (display body) 8-Display light 10-Light passage 11 Driver 12-Holographic lens 13-Display image 15-Sunlight Patent issuer: Nippon Seiki Co., Ltd.

Claims (1)

[Claims] (1) In a vehicle display device that emits display light from a display body through an optical path to a projection member in front of the driver and projects a display image of the display body onto the projection member, the display light is incident on the projection member. The angle of the optical path is set so that the angle is greater than or equal to a critical angle, and the projection member is provided with a holographic lens on which information for reflecting the display light toward the driver at an angle smaller than the incident angle is recorded. A vehicle display device characterized by: