JP6615389B2 - Head-up display device - Google Patents

Description

  The present invention relates to a head-up display device that is mounted on a vehicle or the like and displays various video information.

  In recent years, a head-up display device (hereinafter abbreviated as a HUD device) that displays various types of information on a windshield of a vehicle has been put into practical use as one of the technologies for displaying an image superimposed on a real space. For example, by providing information for a driver as video information to be displayed, driving operation of the vehicle can be supported.

  The basic configuration of the HUD device is that an image optically generated by the image display device is projected 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. It is a configuration. The optical component for image projection includes a reflection mirror, but a surface reflection mirror in which a metal film is formed on the surface of a substrate material such as glass is used to increase the light reflectance.

  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 stacked as a light reflecting layer formed on the surface of glass. .

JP-A-6-51110

  In the HUD device, the image generated by the image display device is reflected by the reflecting mirror and displayed as a virtual image. However, the light reflected near the edge of the reflecting mirror becomes stray light, and is surrounded by the virtual image. There is a problem of appearing as disturbing light. In particular, when the reflecting mirror is a plastic concave mirror, if there are protrusions (burrs) on the parting line of the molded product, a metal film is formed on the burrs, and the light reflected by these burrs becomes stray light, which interferes with the virtual image It becomes.

  In order to suppress the occurrence of the stray light described above, for example, it is conceivable to cover the vicinity of the edge of the reflecting mirror or the vicinity of the parting line with a masking material to eliminate the generation of the reflected light near the edge or the parting line. 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. Further, when the reflecting mirror is a concave mirror, the masking material must be processed along the concave shape, which increases the number of processing steps. In addition, although the round process which rounds the edge vicinity of a reflective mirror is also considered, the effect of stray light prevention was small by examination of this inventor.

  An object of the present invention is to provide a head-up display device that can easily prevent generation of stray light without using a masking material.

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

  According to the present invention, it is possible to provide a head-up display device that can easily prevent the generation of stray light without using a masking material.

The figure which shows the whole structure of a HUD apparatus. 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 reflective mirror (countermeasures against stray light caused by edges). The figure which shows the shape of a concave reflective mirror (measures against the stray light caused by burrs). The figure which shows the modification of the concave surface reflective mirror of FIG. The figure which shows the structural example of a reflecting film.

  Hereinafter, embodiments of a head-up display device (HUD device) according to the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing the overall configuration of the HUD device. The HUD device 1 is housed in a case 10 and is mounted inside a dashboard of a vehicle. The video display device 2 in the HUD device 1 includes a light source such as an LED and a video display element such as a liquid crystal panel, and generates a video to be displayed.

  Video light 8a (shown by a solid line) emitted from the video 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 referred to as a windshield) of the vehicle. Is done. The reflection direction of the first reflection mirror 4 is a flat reflection mirror, and the reflection direction of the second mirror 5 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) is formed on the surface of the substrate, but the planar reflecting mirror 4 has a reflecting film formed on a flat glass substrate. On the other hand, in the concave reflecting mirror 5, a reflecting film is formed on the surface of a plastic molded body that is injection-molded in a concave shape (including a free-form surface shape and an optical axis asymmetric shape). In the present embodiment, the concave reflecting mirror 5 is described as a plastic molded body, but may be a glass molded body.

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

  Here, the image display device 2 also emits ambient light 9a (indicated by a broken line) around the image light 8a. This ambient light 9a is reflected near the edges of the plane reflecting mirror 4 and the concave reflecting mirror 5, and is similarly projected onto the windshield 6. Although this ambient light 9a is white light without a video signal, it is not uniform white light because it is scattered near the edges of the reflecting mirrors 4 and 5, and becomes a streak-like bright line (or dark line) that is visible to the driver. Will be. Hereinafter, this bright line is referred to as “stray light”. When the stray light is generated, not only the quality of the display image of the HUD device 1 is deteriorated but also the interference light with respect to the virtual image 8 visually recognized by the driver. The ambient light 9a is self-luminous emitted from the video display device 2, but 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. On the windshield 6 viewed from the driver, for example, information on the road conditions ahead and the traveling speed is displayed as a virtual image 8. Around the virtual image 8, the stray light 9 by the ambient light 9a shown in FIG. That is, the light reflected in the vicinity of the edges of the reflection mirrors 4 and 5 in the ambient light 9 a appears as stray light 9 around the virtual image 8. In particular, for the concave reflecting mirror 5, since the plastic molding has protrusions (burrs) along the mold dividing position (parting line), the light reflected near the burrs also appears as stray light 9 in the same manner. To do.

  Here, the pattern of the stray light 9 is shown in a simplified manner, but various patterns are obtained depending on the edge shape of the reflection mirrors 4 and 5 and the shape of burrs. That is, depending on the sharpness of the edge and the size of the burr, the thickness and brightness of the stripe-like bright line and the number of bright lines are variously generated. Regarding the sharpness of the edge, in the study by the inventors of the present application, stray light is still generated even when a round process is performed to round the vicinity of the edge.

  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 the reflected light near the edge and the vicinity of the parting line. Possible masking materials include attaching a jig to the edge, sticking black flocked paper, or applying a low-reflection coating. However, there is a problem that it is necessary to newly attach a masking material, and in the case of a concave reflecting mirror, the masking material must be processed into a concave surface. Therefore, in this embodiment, the following measures are taken in order to easily suppress stray light. Hereinafter, when the reflection mirror is a concave reflection mirror, a countermeasure against stray light caused by an edge and a countermeasure against stray light caused by a burr will be described in detail.

  FIG. 3 is a diagram showing the shape of the concave reflecting mirror 5 in which countermeasures against stray light caused by edges are taken. (A) is the front view seen from the reflective surface side, (b) is a side view, (c) is a top view. The reflecting surface of the concave reflecting mirror 5 has a concave shape in the horizontal direction (H direction) and the vertical direction (V direction). A region surrounded by a dotted line on the reflection surface is an effective area 51 where the image light 8a is incident on the concave reflection mirror 5, and a reflection 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 referred to as an invalid area 52. The edges 50 of the concave reflecting mirror 5 are all included in the invalid area 52. However, stray light 9 is generated when ambient light 9a other than the image light other than 8a is incident and reflected near the edge 50.

  Therefore, in this embodiment, in order to eliminate reflection in the vicinity of the edge 50 of the concave reflecting mirror 5, a structure in which no reflecting film is formed in the ineffective area 52 is adopted. Therefore, a jig that covers the ineffective area 52, for example, a masking jig for sputtering film formation, is used in the reflective film forming step. Thereby, since no reflection film is formed in the vicinity of 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 reflective film is not formed in the ineffective area 52 near the edge 50 of the concave reflecting mirror 5, it is not necessary to newly attach a masking material or the like in mounting the concave reflecting mirror 5 on the HUD device 1. Can easily prevent the occurrence of stray light.

  FIG. 4 is a diagram showing the shape of the concave reflecting mirror 5 in which a countermeasure against stray light due to burrs is taken. (A) is the perspective view seen from the reflective surface side, (b) is a partial enlarged view, (c) is a figure which shows the state at the time of film-forming of a reflecting film. Although the concave substrate of the concave reflecting mirror 5 is a plastic molded body by injection molding, a protrusion (burr 53a) exists on the surface along the mold dividing position (parting line 53) when the molded body after injection molding is taken out. . In this example, as shown in (b), a parting line 53 (burr 53a) exists on the side surface of the concave reflecting mirror 5 substantially in parallel with the line of the edge 50. A reflection 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, it may be possible to mechanically remove the burr 53a generated in the parting line 53, but a new fine processing is required.

  In this embodiment, therefore, the reflective film is formed using the masking jig 11 that covers the parting line 53 (burr 53a) when the reflective film of FIG. This eliminates the formation of a reflective film in the vicinity of the parting line 53, eliminates the reflected light from the burr 53a, and suppresses the generation of stray light. The shape of the masking jig 11 is preferably such that it covers both the edge 50 and the burr 53a at the same time, and a countermeasure against stray light caused by the edge and the burr can be realized at the same time.

  FIG. 5 is a diagram showing a modification of the shape of the concave reflecting mirror 5 of FIG. 4 as a countermeasure against stray light caused by burrs. At the time of film formation in FIG. 4C, there is a possibility that the particles of the target material go into the gap between the concave reflecting mirror 5 and the masking jig 11 and be formed on the parting line 53 (burr 53 a). As a countermeasure, 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 stepped portion 55 is a shape that is cut into an L shape by about several millimeters according to the position of the parting line 53, the size of the burr 53a, and the design of the mold. The bottom surface and the wall surface of the step portion 55 may be inclined surfaces.

  FIG. 5C shows an example of the masking jig 11 used at the time of film formation, and the step portion 12 (projection portion) is provided in accordance with the shape of the step portion 55 (notch) provided on the concave reflecting mirror 5. Thereby, it is possible to prevent the target material particles from wrapping around and to reliably prevent the reflective film from being formed on the parting line 53 (burr 53a).

FIG. 6 is a diagram illustrating a configuration example of the reflective film in the present embodiment. On the plastic substrate, the base layer (Nb or Si), the first layer (Al, main reflection layer), the second layer (SiO ₂ ), and the third layer (NbOx) are laminated in this order to increase the reflection of Al. It is a film. A sputtering apparatus was used as the film forming apparatus, and a metal material was used as the masking jig 11. The material shown here is an example and can be appropriately changed according to the application.

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

  The embodiment described above is the case of the concave reflecting mirror 5 in which the reflecting film is formed on the plastic molded body, but can also be applied to the case of the flat reflecting mirror 4 in which the reflecting film is formed on the glass substrate. In that case, it is needless to say that the countermeasure against stray light caused by the edge is similarly effective.

  1: Head-up display (HUD) device.

2: Video display device,
3: Lens,
4: Plane reflection mirror,
5: concave reflecting mirror,
6: Windshield,
8: Virtual image,
8a: image light,
9: stray light,
9a: ambient light,
11: Masking jig
12: Stepped part,
50: Edge,
51: Effective area
52: Invalid area,
53: Parting line
53a: Bali,
55: Stepped portion.

Claims (4)

In a head-up display device that is mounted on a vehicle and displays a virtual image in front of the windshield,
A video display device for generating and emitting video light corresponding to the virtual image;
A reflection mirror that reflects the image light emitted from the image display device and projects the image light onto the windshield, and
The reflection surface of the reflection mirror has a structure in which a reflection film is formed on a surface of a substrate, and the reflection film is not formed in an ineffective area where the image light is not incident. Display device. The head-up display device according to claim 1,
The head-up display device, wherein the invalid area includes an edge of a reflection surface of the reflection mirror. The head-up display device according to claim 2,
The reflection mirror is a concave reflection mirror in which the reflection film is formed on a concave substrate that is a plastic molding, and the reflection film is not formed in the vicinity of a parting line of the plastic molding. A head-up display device. The head-up display device according to claim 3,
When the concave reflecting mirror has the parting line on the side surface of the reflecting surface,
A head-up display device, wherein a step portion is formed from an edge of the reflecting surface to the parting line.

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