JP7252710B2 - head-up display device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a head-up display device mounted on a vehicle or the like to display various image information.

2. Description of the Related Art In recent years, a head-up display device (hereinafter abbreviated as HUD device) that displays various types of information on the windshield of a vehicle has been put to practical use as one of techniques for superimposing and displaying an image on a real space. For example, by providing information for the driver as image information to be displayed, the driving operation of the vehicle can be assisted.

The basic configuration of the HUD device is to project an image optically generated by the image display device onto the windshield, the reflected image light enters the driver's eyes, and the driver visually recognizes the virtual image in front of the windshield. Configuration. Reflecting mirrors are included in optical components for image projection, and in order to increase light reflectance, surface reflecting mirrors are used, which are made by forming a metal film on the surface of a substrate material such as glass.

For example, Patent Document 1 describes a configuration in which a base layer (TiOx), an intermediate layer (AlOy), a reflective layer (Al), and a transparent protective layer are laminated as a light reflecting layer formed on the surface of glass. .

JP-A-6-51110

In the HUD device, an image generated by the image display device is reflected by a reflecting mirror and displayed as a virtual image. There is a problem that it appears and becomes interfering light. Especially when the reflecting mirror is a plastic concave mirror, if there is a protrusion (burr) on the parting line of the molded product, a metal film is formed on the burr, and the light reflected by this burr becomes stray light, interfering with the virtual image. becomes. Alternatively, if sink marks (dents) are generated in the periphery of the reflecting mirror during the plastic molding and cooling process and a metal film is formed thereon, the virtual image reflected by the sink marks will be distorted or double images will occur.

In order to suppress the occurrence of interfering light and virtual image distortion, for example, the vicinity of the edge of the reflecting mirror, the parting line, and the vicinity of the sink mark are covered with a masking material to eliminate the occurrence of the reflected light near the edge, the parting line, and the vicinity of the sink mark. can be considered. However, in that case, it is necessary to newly attach a masking material to the reflecting mirror, which increases the number of parts and the assembly process. Also, if the reflecting mirror is a concave mirror, the masking material must be processed along the concave shape, which increases the number of processing steps. It should be noted that rounding the vicinity of the edge of the reflecting mirror may be considered, but the effect of preventing stray light was small according to the inventor's study.

SUMMARY OF THE INVENTION An object of the present invention is to provide a head-up display device that can easily prevent the occurrence of interfering light and virtual image distortion without using a masking material.

The present invention provides a head-up display device that is mounted on a vehicle and displays a virtual image in front of a windshield, wherein a video display device that generates and emits video light corresponding to the virtual image, and a video display device that emits video light corresponding to the virtual image. a reflecting mirror for reflecting the image light and projecting it onto the windshield, wherein the reflecting surface of the reflecting mirror has a structure in which a reflecting film is formed on the surface of a substrate, and is an ineffective area where the image light does not enter. has a structure in which the reflective film is not formed.

ADVANTAGE OF THE INVENTION According to this invention, the head-up display apparatus which can prevent generation|occurrence|production of obstructive light and virtual image distortion easily can be provided, without using a masking material.

The figure which shows the whole structure of a HUD apparatus (Example 1). The figure which shows typically the virtual image and stray light which are displayed on a windshield. The figure which shows the shape of a concave-surface reflection mirror (countermeasure against stray light resulting from an edge). The figure which shows the shape of a concave-surface reflection mirror (countermeasure against stray light resulting from a burr). FIG. 5 is a diagram showing a modification of the concave reflecting mirror of FIG. 4; FIG. 4 is a diagram showing a configuration example of a reflective film; FIG. 10 is a diagram for explaining sink marks that occur in the peripheral portion of the concave reflecting mirror (Example 2); FIG. 10 is a diagram showing a state during formation of a reflective film; FIG. 10 is a diagram showing a display example of a virtual image pattern as an effect of the second embodiment;

An embodiment of a head-up display device (HUD device) according to the present invention will be described below with reference to the drawings.

In the first embodiment, countermeasures against stray light caused by edges and burrs of the concave reflection mirror 5 in the HUD device will be described.
FIG. 1 is a diagram showing the overall configuration of the HUD device. The HUD device 1 is housed in a case 10 and mounted inside the dashboard of the vehicle. An image display device 2 in the HUD device 1 has a light source such as an LED and an image display element such as a liquid crystal panel, and generates an image to be displayed.

Image light 8a (indicated by a solid line) emitted from the image display device 2 is magnified by the lens 3, reflected by the two reflecting mirrors 4 and 5, and projected toward the windshield 6 (also called windshield) of the vehicle. be done. The first reflecting mirror 4 is a plane reflecting mirror whose reflecting direction is fixed, and the second mirror 5 is a concave reflecting mirror whose reflecting direction is variable by a mirror drive unit 5a. The two reflecting mirrors 4 and 5 have a structure in which a reflecting film (including an aluminum metal film, etc.) is formed on the surface of the substrate. On the other hand, in the concave reflection mirror 5, a reflective film is formed on the surface of a plastic molding that has been injection-molded into a concave shape (including a free curved surface shape and a shape asymmetrical with respect to the optical axis). In this embodiment, the concave reflecting mirror 5 is described as using a molded plastic body, but it may be made of a molded glass body.

The image light 8a emitted from the concave reflecting mirror 5 is reflected by the windshield 6, enters the driver's visual point 7, and forms an image on the retina of the driver so that the image can be visually recognized. At this time, the driver sees the virtual image 8 existing in front of the windshield 6 .

Ambient light 9a (indicated by broken lines) is also emitted from the image display device 2 around the image light 8a. This ambient light 9a is reflected near the edges of the flat reflecting mirror 4 and the concave reflecting mirror 5, and is projected onto the windshield 6 in the same way. This ambient light 9a is white light without a video signal, but because it is scattered near the edges of the reflecting mirrors 4 and 5, it is no longer uniform white light, and becomes streak-like bright lines (or dark lines) and is visually recognized by the driver. will be This bright line is hereinafter referred to as "stray light". When stray light occurs, it not only degrades the quality of the image displayed on the HUD device 1, but also interferes with the virtual image 8 visually recognized by the driver. Although the ambient light 9a is self-luminous emitted from the image display device 2, stray light is also generated when light (external light) incident from the outside of the HUD device 1 is reflected near the edge. .

FIG. 2 is a diagram schematically showing a virtual image and stray light displayed on the windshield. A virtual image 8 is displayed on the windshield 6 seen from the driver, for example, information about road conditions ahead and traveling speed. Around this virtual image 8, stray light 9 due to ambient light 9a shown in FIG. 1 is displayed. That is, of the ambient light 9a, the light reflected near the edges of the reflecting mirrors 4 and 5 appears as stray light 9 around the virtual image 8. FIG. Especially for the concave reflection mirror 5, since the plastic molding has projections (burrs) along the dividing line (parting line) of the mold, the light reflected near the burrs also appears as stray light 9. do.

Although the pattern of the stray light 9 is shown here in a simplified manner, the pattern varies depending on the edge shape of the reflecting mirrors 4 and 5 and the shape of the burr. That is, depending on the sharpness of the edge and the size of the burr, the thickness and brightness of the streak-like bright lines and the number of bright lines vary. With regard to the sharpness of the edge, according to the study by the inventor of the present application, stray light still occurs even if the edge vicinity is rounded.

In order to suppress the stray light described above, it is conceivable to cover the vicinity of the edge of the reflecting mirror and the vicinity of the parting line with a masking material to eliminate the generation of reflected light in the vicinity of the edge and the vicinity of the parting line. As a masking material, it is conceivable to attach a jig to the edge, attach black flocked paper, or apply a low-reflection paint. However, there are problems such as the need to attach a new masking material, and the need to process the masking material to have a concave surface in the case of a concave reflection mirror. Therefore, in this embodiment, the following countermeasures were taken to simply suppress the stray light. In the following, when the reflecting mirror is a concave reflecting mirror, countermeasures against stray light caused by edges and countermeasures against stray light caused by burrs will be specifically described.

FIG. 3 is a diagram showing the shape of the concave reflecting mirror 5, which is designed to deal with stray light caused by edges. (a) is a front view seen from the reflecting surface side, (b) is a side view, and (c) is a top view. The reflecting surface of the concave reflecting mirror 5 is concave in the horizontal direction (H direction) and the vertical direction (V direction). A region surrounded by a dotted line on the reflecting surface is an effective area 51 where the image light 8a is incident on the concave reflecting mirror 5, and a reflecting film is formed on the surface. The outside of the effective area 51 is an area where the image light 8a does not enter, and is called an ineffective area 52 . The edge 50 of the concave reflecting mirror 5 is all included in this invalid area 52, but the ambient light 9a other than the image light 8a enters and is reflected near the edge 50, thereby generating stray light 9. FIG.

Therefore, in this embodiment, in order to eliminate the reflection near the edge 50 of the concave reflecting mirror 5, a structure in which no reflecting film is formed in the invalid area 52 is employed. Therefore, in the step of forming the reflective film, a jig that covers the ineffective area 52, for example, a masking jig for sputtering film formation is used. As a result, since no reflecting film is formed near the edge 50 of the concave reflecting mirror 5, even if the ambient light 9a is incident, the reflected light is not generated, and the generation of stray light can be suppressed.

In this way, if the reflecting film is not formed in the invalid area 52 near the edge 50 of the concave reflecting mirror 5, there is no need to newly attach a masking material or the like when mounting the concave reflecting mirror 5 on the HUD device 1. , the generation of stray light can be easily prevented.

FIG. 4 is a diagram showing the shape of the concave reflection mirror 5, which is used as a countermeasure against stray light caused by burrs. (a) is a perspective view seen from the reflective surface side, (b) is a partially enlarged view, and (c) is a view showing a state during deposition of a reflective film. The concave substrate of the concave reflection mirror 5 is a plastic molded body obtained by injection molding. When the molded body is taken out after injection molding, there are projections (burrs 53a) on the surface along the mold splitting position (parting line 53). . In this example, as shown in (b), a parting line 53 (burr 53a) exists on the side surface of the concave reflection mirror 5 substantially parallel to the line of the edge 50. FIG. A reflective film is formed on the burr 53a, and when the ambient light 9a is incident on the burr 53a, the reflected light similarly becomes stray light. As a countermeasure against this, mechanical removal of the burrs 53a formed on the parting line 53 may be considered, but new fine processing is required.

Therefore, in this embodiment, the masking jig 11 that covers the parting line 53 (burr 53a) is used to form the reflective film during the formation of the reflective film of (c). As a result, the formation of a reflective film in the vicinity of the parting line 53 is eliminated, and the reflected light from the burrs 53a is eliminated, thereby suppressing the generation of stray light. It is desirable that the shape of the masking jig 11 covers both the edge 50 and the burr 53a at the same time, so that the stray light caused by the edge and the burr can be prevented at the same time.

FIG. 5 is a diagram showing a modification of the shape of the concave reflection mirror 5 of FIG. 4 as a countermeasure against stray light caused by burrs. 4(c), particles of the target material may enter the gap between the concave reflecting mirror 5 and the masking jig 11 and form a film on the parting line 53 (burr 53a). As a countermeasure, as shown in FIG. 5(b), a stepped portion (notch) 55 is formed from the edge 50 of the concave reflecting mirror 5 to the parting line 53. As shown in FIG. The shape of the step portion 55 is an L-shaped notch of about several millimeters in accordance with the position of the parting line 53, the size of the burr 53a, and the design of the mold. Note that the bottom surface and the wall surface of the stepped portion 55 may be inclined surfaces.

FIG. 5(c) shows an example of the masking jig 11 used for film formation, in which a stepped portion 12 (protrusion) is provided to match the shape of the stepped portion 55 (notch) provided on the concave reflection mirror 5. FIG. As a result, it is possible to prevent the particles of the target material from wrapping around, and to reliably prevent the reflection film from being formed on the parting line 53 (burr 53a).

FIG. 6 is a diagram showing a configuration example of a reflective film in this embodiment. By laminating a base layer (Nb or Si), a first layer (Al, main reflection layer), a second layer (SiO ₂ ), and a third layer (NbOx) in this order on a plastic substrate, Al reflection is increased. Membrane. A sputtering device was used as the film forming device, and a metal material was used as the masking jig 11 . The materials shown here are only examples, and can be changed as appropriate depending on the application.

In addition, the second layer (SiO ₂ ) and the third layer (NbOx) are transparent protective films, and even if they are formed on the edge 50 of the concave reflection mirror 5 or the parting line 53 (burr 53a), they may cause stray light. should not. Therefore, the second layer and the third layer may be formed without the masking jig 11. FIG.

In the first embodiment, since no reflective film is formed on the ineffective area 52 (edge 50 or burr 53a) of the concave reflecting mirror 5, a new masking material or the like is required when mounting the concave reflecting mirror 5 on the HUD device 1. Since it is not necessary to attach the device to the device, it is possible to easily prevent the generation of interfering light.

Although the above-described embodiments are directed to the concave reflecting mirror 5 having the reflecting film formed on the plastic molding, they can also be applied to the flat reflecting mirror 4 having the reflecting film formed on the glass substrate. In that case, needless to say, it is similarly effective against stray light caused by edges.

In the first embodiment, countermeasures against stray light caused by the edges and burrs of the concave reflection mirror 5 have been explained. . A "sink mark" is a dent (dent) on the surface of a plastic molded article that occurs when it shrinks on cooling.

7A and 7B are diagrams for explaining sink marks occurring in the peripheral portion of the concave reflecting mirror 5. FIG. Here, the shape of the plastic molding before forming the reflective film is shown, (a) is a perspective view seen from the reflective surface side, (b) is a partially enlarged view, and (c) is a cross-sectional view of the end. As shown in (b) and (c), in the peripheral portion of the concave reflecting mirror 5, the height of the reflecting surface is recessed from the designed value over a range of a predetermined width from the edge 50 inward. Hereinafter, this portion will be referred to as a "sink portion 61". The reason for this is that a temperature difference occurs between the central portion and the peripheral portion of the mirror during the cooling process of the plastic molded body. In this example, sink marks 61 are generated in the periphery of each side of the reflecting surface. In particular, as shown in (c), the back side of the mirror has a rib structure 62 to maintain the concave shape, and cooling is delayed in the vicinity of the rib structure, so the amount of sink marks (width and depth of the sink portion 61 ) becomes larger.

If a reflective film is formed on the reflective surface side of the plastic molding having such sink marks 61, the projected virtual image 8 will be distorted or double imaged due to the light reflected by the reflective film of the sink marks 61. . Therefore, in this embodiment, a structure in which no reflective film is formed on the sink portion 61 is adopted so as to prevent the distortion of the virtual image and the generation of the double image.

FIG. 8 is a diagram showing the state of the reflective film when it is formed. A masking jig 21 that covers the sink portion 61 is used to form a reflective film in the same manner as in FIG. 4(c). This eliminates the formation of a reflective film on the sink portion 61 and suppresses the occurrence of virtual image distortion and double images due to reflected light from the sink portion 61 .

FIG. 9 is a diagram showing a display example of a virtual image pattern as an effect of this embodiment. (a) is the case of using a conventional mirror having a sink mark for comparison, and (b) is the case of using the mirror of this embodiment. Here, a grid pattern is used as the virtual image test pattern.

In the case of the conventional mirror of (a), distortion and double images (reference numeral 71) occur in the display pattern in the lower side area 70 of the screen. This is because the recessed portion 61 exists in the corresponding lower side area of the concave reflecting mirror 5, and the reflected light at that portion is disturbed.

On the other hand, in the mirror of this embodiment shown in FIG. 8, the masking film formation shown in FIG. The original display pattern 71 disappears, and the occurrence of virtual image distortion and double images can be prevented. In this example, a pattern with a width of 1 mesh is not displayed in the bottom area.

In other words, using the definition of the effective area 51 and the ineffective area 52 in FIG. is set to not exist. Then, a structure in which no reflecting film is formed in the invalid area 52 is adopted, and the incident range of the image light 8a is adjusted so as to be outside the invalid area 52. - 特許庁The reason why the reflective film is not formed on the ineffective area 52 is that ambient light 9a other than the image light 8a may enter the ineffective area 52, so leaving the reflective film is not desirable.

As described above, in the second embodiment as well, since the reflecting film is not formed in the ineffective area 52 (sink portion 61) of the concave reflecting mirror 5, a masking material or the like is not required when mounting the concave reflecting mirror 5 on the HUD device 1. It is possible to easily prevent the occurrence of virtual image distortion and double images without the need to newly attach the lens.

Needless to say, by appropriately combining the configurations of the first embodiment and the second embodiment, it is possible to suppress the occurrence of interfering light and virtual image distortion caused by the edge of the concave reflection mirror, the parting line (burr), and the sink portion. .

1: Head-up display (HUD) device,
2: video display device,
3: lens,
4: flat reflective mirror,
5: concave reflecting mirror,
6: Windshield,
8: virtual image,
8a: image light,
9: stray light,
9a: ambient light,
11, 21: masking jig,
12: stepped portion,
50: edge,
51: effective area,
52: invalid area,
53: Parting line,
53a: Burr,
55: stepped portion,
61: Sink part,
70: screen bottom area,
71: Virtual image distortion and double images.

Claims (1)

In a head-up display device mounted on a vehicle and displaying a virtual image in front of the windshield,
an image display device that generates and emits image light corresponding to the virtual image;
a reflecting mirror that reflects the image light emitted from the image display device and projects the image light onto the windshield;
The reflecting mirror has a central portion and a peripheral portion . A surface reflecting mirror,
A structure in which the reflective film is not formed on the peripheral portion of the plastic molded body and the rib structure ,
The head-up display device according to claim 1, wherein the peripheral portion extends from the edge of the concave reflecting mirror to the inside over a range of a predetermined width, and is the periphery of each side of the concave reflecting mirror on which the reflecting film is formed.

Images