JP6372346B2 - Head-up display - Google Patents

Description

  The present invention relates to a head-up display that allows a virtual image to be visually recognized on a real scene.

  For example, as described in Patent Document 1, the head-up display includes a polarization control element that projects polarized image light, a polarizing plate that is disposed in front of the polarization control element, and a polarization control element. And a transmission / reflection part that reflects the image light to the user side and visually recognizes it as a virtual image, and the polarizing plate transmits the image light from the polarization control element to the outside of the head-up display and enters from the outside of the head-up display. Polarization is performed so that external light such as sunlight is not directed to the polarization control element side, so that it is prevented that the external light is irradiated on the polarization control element and the temperature rises.

  Also, in Patent Document 2, a DMD (Digital Micro-mirror Device) having a plurality of pixels composed of micromirrors is applied as a reflection type polarization control element, and image light is generated by this DMD, and the generated image light is micro-converted. A head-up display is disclosed in which a virtual image is visually recognized by projecting onto a lens array screen and reflecting an image displayed on the microlens array screen with a transmission / reflection surface.

JP 2000-131682 A JP 2014-085657 A

  However, since the head-up display described in Patent Document 1 includes an engagement portion for attaching a polarization control element and an engagement portion for attaching a polarizing plate to a case body that accommodates an optical member or the like, Since the number of steps for attaching the member to the case body increases, the manufacturing cost may increase.

  Further, as described in Patent Document 2, when a DMD composed of a microlens array screen and a plurality of micromirrors is used as a polarization control element, the DMD micromirror pattern and the microlens array microlens pattern May interfere with each other and cause moire.

  Therefore, the present invention has been made in view of the above circumstances, and an object thereof is to provide a head-up display that can reduce the cost while suppressing the occurrence of moire.

  In order to achieve the above object, a head-up display according to the present invention includes a light source that emits illumination light and a plurality of pixels, and a reflective display that modulates the illumination light to generate and reflect projection light. A lens array screen that diffuses the projection light generated by the reflective display, and reflects or absorbs part of external light incident from the outside, and the lens array An external light reducing member that reduces the external light directed to the screen or the reflective display, and a head-up display that allows a virtual image to be visually recognized by the projection light diffused by the lens array screen, the lens array The screen is disposed to be inclined with respect to the optical axis of the projection light generated by the reflective display, and the external light reducing member is disposed in front of the lens array screen. The one in which is mounted inclined to the plane of the lens array screen.

  According to the present invention, it is possible to reduce costs while suppressing the occurrence of moire.

It is a general-view figure which mounted the head up display in one embodiment of the present invention in vehicles. It is a schematic sectional drawing of the head up display in the said embodiment. It is a figure for demonstrating the structure of the projection apparatus and screen module in the said embodiment.

Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an outline of a head-up display (hereinafter referred to as HUD) 1 according to the present embodiment. The HUD 1 according to the present embodiment is installed in the dashboard of the vehicle 2. The HUD 1 emits the image light 100 to the windshield 2 a of the vehicle 2. The image light 100 reflected by the windshield 2a is directed to an eye box 3 described later. When the user's viewpoint position 3 a is in the eye box 3, the user visually recognizes the virtual image V having a desired luminance generated by the image light 100. The user recognizes that the virtual image V is far away through the windshield 2a so as to overlap the real scene in front of the vehicle 2.

  Hereinafter, the configuration of the HUD 1 will be described with reference to FIGS. FIG. 2 is a schematic cross-sectional view showing the configuration of the HUD 1. FIG. 3 is a diagram for explaining the configuration of the projection device 10 and the screen module 20. In the description using FIGS. 2 and 3, the eye box 3 side is expressed as the front side and the projection device 10 side is expressed as the back side in the light path.

  As shown in FIG. 2, the HUD 1 is a projector (not shown) that performs electrical control of the projector 10, the screen module 20, the folding mirror 30, the concave mirror 40, the case body 50 that houses these, and the HUD 1. A section.

  As shown in FIG. 3, the projection device 10 includes a light source 11 that emits illumination light 300, a light source mirror 12, a prism 13, a reflective display 14, and a projection lens 15, and generates a virtual image V. The projection light 200 is emitted toward the screen module 20.

  The light source 11 includes, for example, a plurality of LEDs capable of outputting red, blue, and green light, and emits the illumination light 300 with a desired color, light intensity, and timing under the control of the control unit. . Further, the projection apparatus 10 according to the present embodiment employs a field sequential color driving method, and the light source 11 of each color emits the illumination light 300 in a time division manner.

  The light source mirror 12 is formed by forming a reflective film on the surface of a base material made of, for example, a synthetic resin material or a glass material by means such as vapor deposition, and the illumination light 300 from the light source 11 is reflected to the reflective display 14. It is incident at an appropriate angle.

  The prism 13 is disposed between the light source mirror 12 and the reflective display 14, and has an inclined surface 13a that is inclined at a predetermined angle with respect to the optical axis of the illumination light 300 incident from the light source mirror 12. The illumination light 300 from the light source mirror 12 incident on the inclined surface 13a is transmitted through the inclined surface 13a, incident on the reflective display 14, and the projection light 200 emitted from the reflective display 14 is again the prism 13. And is reflected toward the projection lens 15 by the inclined surface 13a.

  The reflective display device 14 is a reflective display device such as a DMD (Digital Micromirror Device) or LCoS (registered trademark: Liquid Crystal on Silicon) having a plurality of pixels, and the illumination light 300 incident from the prism 13 is reflected on the reflective display device 14. Under the control of the control unit, the light is modulated to the projection light 200 for displaying the virtual image V and reflected toward the prism 13.

  The projection lens 15 is formed of, for example, a convex lens, and expands the projection light 200 incident from the prism 13 and emits it in the direction of the screen module 20.

  The screen module 20 engages the lens array screen 21, the hot mirror 22 disposed on the front side of the lens array screen 21, and the lens array screen 21 and the hot mirror 22 with a gap S therebetween. And a holder 23, which are modularized by engaging with each other, and arranged so that the light receiving surface (the back side of the lens array screen 21) is inclined with respect to the projection light 200 emitted from the projection device 10. The

The lens array screen 21 is a microlens array in which a plurality of convex microlenses are arranged on the front side. The projection light 200 from the projection device 10 is received on the back side, diffused by the microlenses, and transmitted to the folding mirror 30 side. To do. Part of the light diffused by the lens array screen 21 is oriented as image light 100 to the eye box 3 via the folding mirror 30, the concave mirror 40, and the like. The lens array screen 21 orients the image light 100 so that the brightness of the virtual image V viewed in the eye box 3 is viewed substantially uniformly.
The normal direction 21a of the lens array screen 21 is disposed to be inclined by an angle θ1 with respect to the optical axis 200a of the projection light 200 emitted from the projection device 10. The angle θ1 is set to an angle at which moire generated due to interference between the microlens array pattern of the lens array screen 21 and the pixel pattern of the reflective display 14 does not occur (reduced so that it cannot be visually recognized). Specifically, it is set between about 0.5 to 3 degrees. The lens array screen 21 is engaged with the front side of a rear side of an opening 23 a described later of the holder 23.

  The hot mirror 22 has a characteristic of transmitting visible light and reflecting and absorbing infrared light. The hot mirror 22 efficiently transmits the image light 100 composed of visible light that has passed through the lens array screen 21 to the folding mirror 30 side, and reflects and absorbs infrared light from sunlight (external light) incident from the outside. . The normal direction 22a of the hot mirror 22 is arranged to be inclined by an angle θ2 with respect to the optical axis 200a of the projection light 200 emitted from the projection device 10. The angle θ2 is larger than the angle θ1, and is set to an angle at which the external light incident on the front side of the hot mirror 22 is not reflected to the folding mirror 30 side. Specifically, the angle θ2 is set to about 15 degrees. Is done. Further, the front side of an opening 23 a (described later) of the holder 23 is engaged with the back side of the hot mirror 22.

  The holder 23 is made of a translucent synthetic resin material and is formed in a rectangular tube shape having a rectangular opening 23a. One end of the opening 23a of the holder 23 is formed to be inclined with respect to the other end. Therefore, the holder 23 is provided with the lens array screen 21 on the back side of the opening 23 a of the holder 23 and the hot mirror 22 on the front side, so that the hot mirror 22 is inclined with respect to the lens array screen 21. Can be arranged.

  The folding mirror 30 is formed by forming a reflective film on the surface of a base material made of, for example, a synthetic resin material or a glass material by means of vapor deposition or the like, and a concave mirror described later for the image light 100 diffused by the lens array screen 21. Reflected toward 40.

  The concave mirror 40 is formed, for example, by forming a reflection film on the surface of a base material made of a synthetic resin material by means such as vapor deposition. The curvature of the concave mirror 40 has a concave free-form surface. The reflected image light 100 is enlarged and reflected toward the windshield 2a.

  The case body 50 is a substantially box-shaped member made of, for example, a metal material such as aluminum, and is provided with various engaging portions (not shown) therein. In the present embodiment, the projection device 10 and the screen module are provided. 20, the folding mirror 30, and the concave mirror 40 are held in a predetermined positional relationship. Further, the inner surface of the case body 50 is painted black, for example, so that stray light caused by the outside of the HUD 1 or the projection device 10 is less likely to occur. Further, a translucent portion 51 formed of a transparent resin material or the like that transmits the image light 100 reflected by the concave mirror 40 is provided on the front surface side of the case body 50.

  The above is the configuration of the HUD 1 in the present embodiment. The HUD 1 in the present embodiment has a light source 11 that emits the illumination light 300 and a plurality of pixels. The projection light is modulated by modulating the illumination light 300 that the light source 11 emits. A reflective display 14 for generating and reflecting 200, a lens array screen 21 having a plurality of arrayed microlenses and diffusing the projection light 200 generated by the reflective display 14, and an external incident from the outside A hot mirror 22 that reflects or / and absorbs part of the light and reduces external light directed to the lens array screen 21 or the reflective display 14, and a virtual image by the projection light 200 diffused by the lens array screen 21 V is visually recognized, and the lens array screen 21 is arranged to be inclined with respect to the optical axis 200a of the projection light 200 generated by the reflective display 14, and Mirror 22, the front surface of the lens array screen 21 is to be attached inclined with respect to the surface of the lens array screen 21.

  As described above, the lens array screen 21 is arranged to be inclined with respect to the optical axis 200a of the projection light 200, so that moire can be reduced. Further, by arranging the hot mirror 22 to be inclined to the front surface of the lens array screen 21, the hot mirror 22 can reflect outside light in a direction different from the direction of the image light 100 emitted from the lens array screen 21. In addition, it is possible to suppress a decrease in contrast of the virtual image V that occurs when reflected light of outside light travels toward the eye box 3. Further, by attaching the hot mirror 22 to the front surface of the lens array screen 21 and modularizing it as the screen module 20, it is possible to reduce the number of man-hours for manufacturing than attaching the lens array screen 21 and the hot mirror 22 to the case body 50 individually. And cost reduction is possible.

  The holder 23 has a cylindrical shape having an opening 23a. The lens array screen 21 is engaged with the back surface of the opening 23a, and the external light reducing member is engaged with the front surface of the opening 23a. By modularizing the mirror 22 with the holder 23 therebetween, the hot mirror 22 can be tilted with respect to the lens array screen 21 with high accuracy. By assembling the screen module 20 to the engaging portion (not shown) of the case body 50, the angles of both the lens array screen 21 and the hot mirror 22 can be accurately defined without increasing the number of man-hours for manufacturing.

  The screen module 20 does not have the holder 23 and bonds the lens array screen 21 and the hot mirror 22 with an adhesive so that the hot mirror 22 is inclined with respect to the lens array screen 21. It may be a configuration.

  Further, the holder 23 in the present embodiment may be formed of a member having a lower thermal conductivity than the lens array screen 21. With such a configuration, even when the hot mirror 22 is heated to high temperatures due to external light irradiation, heat is hardly transmitted to the lens array screen 21 via the holder 23, so that the lens array screen 21 expands due to heat and has optical characteristics. It can prevent that the display quality of the virtual image V which a user changes visually falls. Further, since the holder 23 is engaged with the lens array screen 21 and the hot mirror 22 so that there is a gap S between the lens array screen 21 and the hot mirror 22, the heat of the hot mirror 22 passes through the gap S. It is difficult to be transmitted to the lens array screen 21.

  Further, the hot mirror 22 may be arranged such that the lens array screen 21 is further tilted in the same direction as the tilted direction with respect to the optical axis 200 a of the projection light 200. With such a configuration, the normal direction 22a of the hot mirror 22 can be greatly inclined with respect to the optical axis 200a of the projection light 200 while suppressing the relative inclination between the hot mirror 22 and the lens array screen 21 to be small. By suppressing the relative inclination between the hot mirror 22 and the lens array screen 21 to be small, the image light 100 emitted from the lens array screen 21 is less likely to be reflected by the back surface of the hot mirror 22 and is efficiently transmitted. The virtual image V can be displayed while suppressing the loss of the image. Further, by tilting the normal direction 22a of the hot mirror 22 with respect to the optical axis 200a of the projection light 200, the direction of the external light reflected by the front surface of the hot mirror 22 and the image light 100 transmitted through the hot mirror 22 are increased. The direction can be made greatly different, and the contrast reduction of the virtual image V that occurs when the reflected light of the outside light goes to the eye box 3 can be suppressed.

  Further, since the holder 23 is formed of a translucent member, the projection light 200 transmitted through the lens array screen 21 can be efficiently directed to the folding mirror 30 without being blocked.

  Further, the case body 50 may be engaged with the lens array screen 21 and not engaged with the hot mirror 22. With such a configuration, the heat of the hot mirror 22 is transmitted to the engaging portion (not shown) of the case body 50, thereby preventing the engaging portion from thermally expanding and changing the installation angle of the hot mirror 22. can do.

  In the above description, in order to facilitate the understanding of the present invention, the description of known unimportant technical matters is appropriately omitted.

1 HUD (head-up display)
2 Own vehicle 2a Windshield (transmission reflection surface)
3 Eye box 3a User's viewpoint position 10 Projector 11 Light source 12 Light source mirror 13 Prism 14 Reflective display 15 Projection lens 20 Screen module 21 Lens array screen 22 Hot mirror (external light reducing member)
23 Holder 23a Opening 30 Folding mirror 40 Concave mirror 50 Case body 51 Translucent part

100 Image light 200 Projection light 200a Optical axis of projection light 300 Illumination light

S gap V virtual image

Claims (6)

A light source that emits illumination light;
A reflective display that has a plurality of pixels and modulates the illumination light to generate and reflect projection light;
A lens array screen having a plurality of microlenses arranged to diffuse the projection light generated by the reflective display;
An external light reducing member that reflects or absorbs part of external light incident from the outside and reduces the external light directed to the lens array screen or the reflective display, and is diffused by the lens array screen A head-up display for visually recognizing a virtual image by the projection light,
The lens array screen is disposed to be inclined with respect to the optical axis of the projection light generated by the reflective display,
The external light reduction member is attached to the front surface of the lens array screen so as to be inclined with respect to the surface of the lens array screen.
A head-up display. The outside light reducing member is further inclined in the same direction as the direction in which the lens array screen is inclined with respect to the optical axis of the projection light.
The head-up display according to claim 1. A cylindrical shape having an opening, further comprising a holder for engaging the lens array screen with one of the openings and engaging the external light reducing member with the other of the openings;
The head-up display according to claim 1, wherein the head-up display is provided. The holder is formed of a member having a lower thermal conductivity than the lens array screen.
The head-up display according to claim 3. The holder is formed of a translucent member.
The head-up display according to claim 3 or 4, characterized in that. A case body for storing at least the lens array screen and the external light reducing member;
The case body engages with the lens array screen and does not engage with the external light reducing member;
The head-up display according to claim 1, wherein the head-up display is provided.

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