JP7639445B2 - Head-up display device - Google Patents

Description

The present invention relates to a head-up display device.

Conventional head-up display devices are known, for example, from the configurations shown in Patent Document 1 and Patent Document 2.

JP 2017-102305 A International Publication No. 2020-153474

In conventional configurations, there was a risk of variation in resistance to external disturbances in the cover glass (the dustproof sheet (24) in Patent Document 1 and the light-transmitting cover (50) in Patent Document 2) covering the opening of the case of the head-up display device.
SUMMARY OF THE PRESENT EMBODIMENT In view of the above-mentioned problems, an object of the present invention is to provide a head-up display device having improved resistance to disturbances.

In order to achieve the above object, a head-up display device according to the present invention comprises:
A head-up display device mounted inside a covering member located substantially below a windshield of a vehicle,
a display that generates display light that is projected onto the windshield;
a case that houses the display and has an opening through which the display light passes to the windshield;
a light-transmitting cover covering the opening and having a light-transmitting region through which the display light passes and a light-shielding region positioned so as to surround the light-transmitting region;
an adhesive member for attaching the light-transmitting cover to the case;
Equipped with
The adhesive member adheres the light-transmitting cover to the area covered by the covering member.

1 is a diagram showing a cross section of a head-up display 1 according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of a main portion of the head-up display 1. 2 is an external view of the head-up display 1 through the instrument panel P when viewed from a viewpoint EP. FIG. 1 is a diagram illustrating a conventional head-up display.

Hereinafter, a head-up display device according to an embodiment of the present disclosure will be described with reference to the accompanying drawings.

1. First embodiment <1-1. Configuration>
<1-2. About Figure 2>
2. Modifications

[1. First embodiment]
<1-1. About the composition>
1 is a diagram showing a cross section in the YZ plane of a head-up display 1 (HUD1), which is an example of a head-up display device. The HUD 1 is mounted inside a covering member located substantially below the windshield WS of a vehicle C. The covering member may be, for example, an instrument panel P that houses instruments and a center information display of the vehicle C, or an exterior case that is covered with synthetic resin or leather.

The HUD1 emits display light Li to the windshield WS. The display light Li is generated by lighting means and display means inside the HUD1. The generated display light Li travels through an optical system (a correction mirror 31 and a concave mirror 32 described below) and is emitted from an opening 51 in the case 50. By visually recognizing the display light Li reflected by the windshield WS from the viewpoint EP, the passenger (user) can see a rectangular virtual image V at a position several meters to several tens of meters away from the windshield WS in the F direction. In this case, the user in the driver's seat can use the display output by the HUD1.

The ray connecting the center of the screen 23, which is an example of a display surface described below, and the center of the eye box, which is the center of the space in which the virtual image V can be viewed, is called the Gatley GR.

The virtual image V displays information that is highly necessary to alert the occupant (user), such as vehicle information such as the speed and engine RPM of the vehicle C, route guidance displays such as turn-by-turn and maps, and warning displays such as blind spot indicators and speed limit exceeding warnings. This provides a driving environment that reduces the need to move the viewpoint and adjust the focal length of the eyes. The virtual image V includes characters and icons indicating this information as well as a background portion, and when viewed from the occupant in a plan view, it has, for example, a roughly rectangular shape.

The HUD 1 includes a projector 21, a field lens 22, a screen 23, a correction mirror 31, a concave mirror 32, a control board (not shown), a case 50, and a cover glass 52.

The projector 21, field lens 22, and screen 23 are an example of a display configuration that emits display light Li from a display surface (screen 23), and are not limited to the following configuration.

The projector 21 emits projection light PL using a field sequential method, and can be a known projector that is composed of a red light source, a green light source, a blue light source, a dichroic mirror, a DMD (Digital Micro-Mirror Device), a prism, a projection lens (including an exit pupil), etc.

The red, green, and blue light sources are composed of LEDs of each color, which light up in sequence in response to signals sent from an electrically connected control board. When lit, each light source emits a light beam of each color (illumination light) toward a dichroic mirror located above the light source in the drawing. Instead of being composed of LEDs of each color, it can also be composed of a white LED with a transmissive color filter of each color provided in the emission direction, or it can be composed of a rotating transmissive color filter with each color evenly applied to the outer edge.

A dichroic mirror is a reflective/transmissive component that can transmit or reflect light in a specific wavelength range, and transmits/reflects each color of light in the direction where the DMD is located.

The DMD, or Digital Micro-mirror Device, is a light modulation element that reflects light in a specified direction by changing the angle of tiny mirrors arranged in a matrix on the plane of incidence of the illumination light in response to a control signal from a control board. In this embodiment, the color light rays that are transmitted/reflected by the dichroic mirror are reflected in the direction of the prism or in other directions that do not affect the display of the virtual image V in accordance with the angle of the mirror.

The prism transmits each color of illumination light that enters the DMD, and holds each color of light reflected from the DMD so that it can be reflected toward the projection lens.

The projection lens is made up of at least one lens and emits the light reflected by the prism as projection light PL to be imaged on the screen.

The projector 21 emits projection light PL by selectively reflecting each color light source using the above configuration.

The field lens 22 is disposed near the screen 23 and is a lens that adjusts the light distribution of the projection light PL to make the image, particularly in the peripheral area, clearer. For this reason, it is desirable to position the screen 23 and the field lens 22 in approximately parallel positions.

The screen 23 is a transmissive screen that can be composed of a microlens array, a diffusion plate, etc., and is a member that diffuses and transmits the projection light PL as display light toward the correction mirror 31. The screen 23 is illuminated by the projection light PL and emits the display light Li.

The above configuration forms a display that emits display light Li from the display surface (screen 23).

The correction mirror 31 and the concave mirror 32 form a reflective optical system. The reflective optical system reflects the display light Li emitted by the screen 23 so that it is emitted to the windshield WS.

The correction mirror 31 is, for example, a free-form mirror. The correction mirror 31 is a mirror having a free-form shape, particularly a concave shape in the vertical direction of the drawing and a convex shape in the depth direction of the drawing. Due to this shape, the display light Li is reflected so as to cross in the vertical direction of the drawing.

The concave mirror 32 is a reflective member that magnifies the first display light while reflecting it toward the opening (cover glass 52) of the case 50. The correction mirror 31 and the concave mirror 32 can be made of synthetic resins such as PC-PET (polycarbonate polyethylene terephthalate) and PMMA (polymethyl methacrylate resin, acrylic) or inorganic glass as a base material. These mirrors can be formed by applying aluminum vapor deposition to the mirror surface.

The mirrors that make up the optical system may take other forms.
For example, a multilayer interference film with different film thicknesses may be formed on one side of a plate-shaped glass substrate by a method such as vapor deposition, and the film may be a cold mirror that transmits infrared light and reflects at least visible light, a mirror with polarizing properties, or an ordinary flat mirror.

The cover glass 52, which is an example of a light-transmitting cover, can be a transparent synthetic resin substrate in the form of a plate of uniform thickness, and can be made of, for example, PMMA or polycarbonate. The cover glass 52 is attached while curving so as to cover the opening 51 of the case 50. The detailed configuration will be described later.

The control board can be a microcomputer equipped with a memory unit such as a ROM or RAM (not shown) used for storing predetermined programs and various data, and as a memory area during calculations, a CPU for performing calculations according to the predetermined programs, and an input/output interface, etc. Based on vehicle information received from external in-vehicle devices, the control board generates images to be displayed on the display means, controls the display of the display means, and controls the illuminance of the lighting means.

The case 50 is a container that can be made of resin or metal molding, and has an opening 51 for emitting the display light Li to the outside of the device, with a cover glass 52 attached to cover this opening 51. Inside, the projector 21, field lens 22, screen 23, correction mirror 31, concave mirror 32, and control board are fixed by known means such as fitting, locking, bonding with adhesive materials, and screwing with screws.

<1-2. About Figure 2>
2 is a cross-sectional view of a main part in the YZ plane of the HUD 1. The configuration of the HUD 1 will be described with reference to FIG.

The cover glass 52 has a light-transmitting region 52a and a light-shielding region 52b.
As described above, the light-transmitting region 52a is transparent so as to emit the display light Li to the windshield WS.

The light-shielding area 52b is different from the light-transmitting area 52a in that it does not transmit light. The light-shielding area 52b is an area for concealing parts of the components constituting the HUD 1 that do not need to be visible from the outside, such as the attachment surface 50a of the case 50. In this disclosure, the light-shielding area 52b is shown in a form in which both the upper and lower surfaces of the cover glass 52 are printed in a dark color (e.g., black). However, the invention is not limited to this, and printing may be applied to only one of the surfaces, or the area may be formed by attaching a dark-colored sheet such as baffle foam instead of printing.

The double-sided tape 53, which is an example of an adhesive member, attaches the cover glass 52 to the attachment surface 50a of the case 50. The adhesive member is not limited to the double-sided tape 53, and may be a silicone-based adhesive or an epoxy-based adhesive that does not have a base material.

Conventionally, the configurations of Patent Documents 1 and 2 have employed a configuration in which a cover glass is attached to a case in a light-shielding area. Furthermore, since the cover glass of the head-up display transmits display light to the correct position through a light-transmitting area in the center, it is undesirable for the position to shift or vibrate. Therefore, as shown in the prior art documents, the adhesive member is attached close to the light-transmitting area so that it always follows the light-transmitting area. A head-up display 2 configured from this technical viewpoint is shown in Figure 4.

However, the inventors of the present application have found that the above configuration may actually reduce the product's resistance to disturbances. Specifically, they have found that there is a risk that the state of the cover glass may change in response to disturbances such as the incidence of sunlight.

This is because, when the adhesive member is attached at a location below the light-shielding area and along the light-transmitting area, the adhesive member is attached at a location that is not covered by the instrument panel. As a prerequisite, the opening (second opening) of the instrument panel is generally provided wider than the light-transmitting area. This is because, as described above, it is not preferable for a member through which the display light passes to obstruct the passage of the display light, and a member such as the instrument panel, which has a relatively lower positioning accuracy than the cover glass, needs to have an opening wider than the light-transmitting area with a margin.
Therefore, in the conventional configuration, the adhesive member is attached to a portion of the light-shielding area that is not covered by the instrument panel.

However, with the conventional configuration, adhesive members located in areas not covered by the instrument panel could be heated by the shaded areas exposed to sunlight, which could cause gas generation or deformation.

Therefore, this disclosure discloses a mode in which the double-sided tape 53 is attached at a location covered by the instrument panel P. In addition, it is desirable to attach the double-sided tape 53 at a location away from the light-transmitting area 52a and the opening 51.

FIG. 3 is a diagram showing the appearance of the HUD 1 through an instrument panel P when viewed from the vicinity of a viewpoint EP.
In the above explanation, a configuration has been shown in which double-sided tape 53 is provided in a location covered by instrument panel P to prevent heating by sunlight SL. However, in this configuration, attachment surface 50a is positioned so as to protrude outside the device, which increases the size of the device.

In this disclosure, the light-transmitting area 52a is formed in a shape surrounded by curves and straight lines, and this shape includes a first side E (the boundary side between the light-transmitting area 52a and the light-shielding area 52b) of the light-transmitting area 52a located at the rear (driver's seat side) of the vehicle C, and the double-sided tape 53 attaches the cover glass 52 to the case 50 at the location of the light-shielding area 52b covered by the instrument panel P on the side corresponding to the first side E (the edge of the cover glass 52 on the first side E side), and the double-sided tape 53 attaches the cover glass 52 at the location along the light-transmitting area 52a on the other sides.

The first side E is a side of the outer shape of the light-transmitting area 52a that is located at the rear of the vehicle, and the light-shielding area 52b near this side is more likely to be exposed to sunlight than other parts. This is because the HUD 1 is housed inside the instrument panel P.
Therefore, the double-sided tape 53 corresponding to the first side E is provided only in the area covered by the instrument panel P, and the other double-sided tape 53 is provided in areas not covered by the instrument panel P. With this configuration, the increase in size of the device is kept to a minimum.
2. Modifications

The vehicle head-up display of the present invention has been described using the configuration of the above-mentioned embodiment as an example, but the present invention is not limited to this, and it goes without saying that various improvements and changes to the display are possible in other configurations without departing from the gist of the present invention.

For example, the projector 21, the field lens 22, and the screen 23 constitute a display, but this is not limiting. For example, in section 1-1, the field lens 22 is not a required component, so a display using an electronic display such as a liquid crystal display element or an organic EL display element as the display surface may also be used.

The projector 21 may also be configured to use LCOS (Liquid Crystal On Silicon) or TFT (Thin Film Transistor) as a light modulation element.

In addition, a correction mirror 31 and a concave mirror 32 are used as mirrors that make up the optical system. However, these may be other mirror components, such as a plane mirror or a cold mirror.

Also, a mode in which the projection light PL is projected directly onto the screen 23 has been shown. The projection light PL may be appropriately reflected by a mirror between the screen 23 and the projector 21.

C vehicle V virtual image EP viewpoint WS windshield P instrument panel (covering member)
E First Side

PL Projection light Li Display light SL Sunlight GR Gatley

1. Head-up display (HUD)
21 Projector 22 Field lens 23 Screen 31 Correction mirror 32 Concave mirror 50 Case 50a Attachment surface 51 Opening 52 Cover glass (translucent cover)
52a: light-transmitting region; 52b: printing region; 53: double-sided tape (adhesive member)

Claims (3)

A head-up display device mounted inside a covering member located substantially below a windshield of a vehicle,
a display that generates display light that is projected onto the windshield;
a case that houses the display and has an opening through which the display light passes to the windshield;
a light-transmitting cover covering the opening and having a light-transmitting region through which the display light passes and a light-shielding region positioned so as to surround the light-transmitting region;
an adhesive member for attaching the light-transmitting cover to the case;
Equipped with
The adhesive member adheres the light-transmitting cover to a portion covered by the covering member. The adhesive member is
In a portion of the outer shape of the light-transmitting region that is located at the rear of the vehicle , the light-transmitting cover is attached to a portion that is covered by the covering member;
The head-up display device according to claim 1 , wherein the light-transmitting cover is attached to other portions along the light-transmitting region. The head-up display device according to claim 1 , wherein the cover member is an instrument panel.

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