JP7005107B2 - Display device for vehicles - Google Patents

Description

The present invention relates to a vehicle display device.

Conventionally, there are display devices for vehicles such as a head up display (HUD) device that displays a virtual image in front of the driver via a windshield of the vehicle. For example, Patent Document 1 discloses a display device that changes the angle of a concave mirror that projects an image toward a windshield according to the height of the eye point of a driver and moves the projection position of the image.

By the way, Patent Documents 2 and 3 disclose an image display device or the like that scans a laser beam and projects an image by using a scanning mirror using a MEMS (Micro Electro Mechanical System) technology.

Japanese Unexamined Patent Publication No. 2016-101805 Japanese Patent No. 5018627 Japanese Patent No. 5587403

However, in the conventional vehicle display device, since the reflection mirror that projects the image toward the windshield is not fixed, the angle of the reflection mirror shifts due to the vibration of the vehicle or the like, and the projection position of the image changes. There is a risk that it will end up.

An object of the present invention is to provide a vehicle display device capable of changing the projection position of an image without moving a reflection mirror.

In order to achieve the above object, the vehicle display device according to the present invention corresponds to a projector that emits a laser beam corresponding to an image to be visually recognized by a vehicle driver, and the laser beam emitted from the projector. A projected member on which the image is projected and transmitting the laser beam, and a reflection mirror that reflects the laser beam transmitted through the projected member and reflected toward the windshield of the vehicle are provided. The projector reflects at least one light source that outputs the laser beam and the laser beam from the light source in the main scanning direction of the projected surface of the projected member, and is orthogonal to the main scanning direction. A scanning mirror that scans while reflecting light in the scanning direction, and the scanning mirror that projects the image onto a scanning region that is narrower in the sub-scanning direction than the scannable region that can be scanned by the scanning mirror in the projected member. The scanning mirror driving means can move the scanning area in the scannable area in the sub-scanning direction by driving the scanning mirror. The scanning mirror is driven so that the target scanning area capable of projecting the image at a position corresponding to the eye point of the driver obtained from the vehicle and the scanning area overlap, and the target scanning area moves the eye point. It is characterized in that the position in the sub-scanning direction is changed by determining the scanning angle of the scanning mirror in the sub-scanning direction according to the amount of change in the direction .

In the vehicle display device, it is preferable that the moving direction of the eye point and the sub-scanning direction are parallel.

According to the vehicle display device according to the present invention, there is an effect that the projection position of the image can be changed without moving the reflection mirror.

FIG. 1 is a diagram showing a schematic configuration of a vehicle display device according to an embodiment. FIG. 2 is a diagram showing a schematic configuration of a projector according to an embodiment. FIG. 3 is a diagram illustrating scanning of the screen by the MEMS mirror according to the embodiment. FIG. 4 is a diagram illustrating scanning switching of the screen by the MEMS mirror according to the embodiment. FIG. 5 is a diagram showing an example of an energization current waveform to the MEMS mirror according to the embodiment. FIG. 6 is a diagram showing the relationship between the position of the eye point and the projection position of the image in the embodiment. FIG. 7 is a diagram showing an example of an image projected by the vehicle display device according to the embodiment.

Hereinafter, embodiments of the vehicle display device according to the present invention will be described in detail with reference to the drawings. The present invention is not limited to this embodiment. In addition, the components in the following embodiments include those that can be easily assumed by those skilled in the art or those that are substantially the same. In addition, the components in the following embodiments may be omitted, replaced, or modified in various ways without departing from the gist of the invention.

[Embodiment]
FIG. 1 is a diagram showing a schematic configuration of a vehicle display device according to an embodiment. FIG. 2 is a diagram showing a schematic configuration of a projector according to an embodiment. FIG. 3 is a diagram illustrating scanning of the screen by the MEMS mirror according to the embodiment. FIG. 4 is a diagram illustrating scanning switching of the screen by the MEMS mirror according to the embodiment. FIG. 5 is a diagram showing an example of an energization current waveform to the MEMS mirror according to the embodiment. FIG. 6 is a diagram showing the relationship between the position of the eye point and the projection position of the image in the embodiment. FIG. 7 is a diagram showing an example of an image projected by the vehicle display device according to the embodiment. Note that FIG. 1 shows the positional relationship of each element when the vehicle equipped with the vehicle display device is viewed from the side. FIG. 7 shows how the driver looks from the eye point.

As shown in FIG. 1, the vehicle display device 1 according to the embodiment is a head-up display (HUD) device mounted on a vehicle 100 such as an automobile, for example. The vehicle display device 1 is arranged inside the dashboard (not shown) of the vehicle 100, and projects images corresponding to various information about the vehicle 100 on the windshield 101 of the vehicle 100. Various information about the vehicle 100 includes, for example, information for supporting the driving of the driver (driver) 200 such as vehicle speed, vehicle condition, and road information. The vehicle display device 1 projects an image on the windshield 101 and displays a virtual image 110 in front of the eye point 201. The virtual image 110 is an image to be visually recognized by the driver 200 on the eye point 201. The windshield 101 has semi-transparency and reflects the laser beam incident from the vehicle display device 1 toward the eye point 201. The eye point 201 is a predetermined position as a viewpoint position of the driver 200 seated in the driver's seat (not shown) of the vehicle 100. The driver 200 recognizes the image reflected by the windshield 101 as a virtual image 110. The virtual image 110 is perceived by the driver 200 as if it were in front of the windshield 101. As shown in FIG. 1, the vehicle display device 1 includes a projector 3, a screen 5, an aspherical mirror 7, and a housing 9.

The projector 3 is a projector. The projector 3 is arranged at a position facing the screen 5. The projector 3 emits a laser beam 11 corresponding to an image visually recognized by the driver 200. The projector 3 projects an image on the screen 5 by emitting a laser beam 11 toward the screen 5. As shown in FIG. 2, the projector 3 has a light source unit 30, a first light source 31, a second light source 32, a third light source 33, dichroic mirrors 34 and 35, and a scanning mirror 36. The light source unit 30 includes a first light source 31 to a third light source 33 and dichroic mirrors 34 and 35.

The projector 3 has three light sources that output laser beams having different wavelengths from each other. That is, the first light source 31 is, for example, a laser diode that outputs a red laser beam. As shown in FIG. 2, the red laser beam output from the first light source 31 is applied to the dichroic mirror 34. The second light source 32 is a laser diode that generates a green laser beam having a wavelength different from that of the red laser beam. The green laser light output from the second light source 32 is applied to the dichroic mirror 34. The third light source 33 is a laser diode that generates a blue laser beam different from the red laser beam and the green laser beam. The blue laser light output from the third light source 33 is applied to the dichroic mirror 35.

The dichroic mirror 34 transmits the red laser light and reflects the green laser light. The red laser light and the green laser light reflected by the dichroic mirror 34 become laser light on the same optical axis and are incident on the dichroic mirror 35. The dichroic mirror 35 transmits red and green laser light and reflects blue laser light. The red and green laser light and the blue laser light reflected by the dichroic mirror 35 are combined and incident on the scanning mirror 36 as laser light on the same optical axis. That is, the optical system including the dichroic mirrors 34 and 35 combine three laser beams of red, green, and blue.

As shown in FIG. 2, the scanning mirror 36 reflects the laser beam 11 from the light source unit 30 in the main scanning direction of the projected surface of the screen 5 and in the sub-scanning direction orthogonal to the main scanning direction. Scan. The scanning mirror 36 projects an image on the screen 5 by reflecting the laser beam 11 toward the screen 5 while rotating and vibrating around the two orthogonal rotation axes X1 and X2. The scanning mirror 36 is, for example, a MEMS mirror produced using MEMS technology. A MEMS mirror is an optical device in which mechanical element parts, sensors, actuators, electronic circuits, and the like are integrated on a semiconductor substrate. The scanning mirror 36 includes a stage portion 37, a mirror portion 38, and the like.

The laser beam 11 reflected by the scanning mirror 36 scans the screen 5 in the main scanning direction by the mirror portion 38 of the scanning mirror 36 rotating and vibrating around the rotation axis X1. Further, the laser beam 11 scans the screen 5 in the sub-scanning direction by the mirror portion 38 of the scanning mirror 36 rotating and vibrating around the rotation axis X2. That is, the projector 3 projects an image on the screen 5 while scanning the screen 5 in the main scanning direction and the sub-scanning direction by the laser beam 11 which is the reflected light of the scanning mirror 36.

The stage portion 37 is a plate-shaped member having a through hole, and is arranged in the through hole of the scanning mirror 36 main body. The stage portion 37 is connected to the scanning mirror 36 main body by two beams extending in the rotation axis X2 direction. A coil (not shown) wound in a spiral shape is arranged on the surface of the stage portion 37. Power is supplied to this coil from the scanning mirror 36 main body side. When the coil is supplied with electric power, the stage portion 37 rotates relative to the scanning mirror 36 with the rotation axis X2 as the center of rotation.

The mirror portion 38 is a disk-shaped member. The mirror portion 38 is arranged in the through hole of the stage portion 37. The mirror portion 38 is connected to the stage portion 37 by two beams extending in the rotation axis X1 direction. The rotation axis X1 and the rotation axis X2 are orthogonal to each other. The mirror portion 38 rotationally vibrates around the rotation axis X1 due to resonance. That is, the mirror portion 38 rotates relative to the stage portion 37 due to resonance. Specifications such as the mirror unit 38 are designed so that when the stage unit 37 rotates and vibrates at a predetermined first frequency, the mirror unit 38 rotates and vibrates at a second frequency due to resonance.

The screen 5 is a projected member. The entire screen 5 is formed in a flat shape and is arranged at a position facing the projector 3. The screen 5 is a transmissive screen that transmits light. The screen 5 is composed of a microlens array, a diffuser, and the like. The screen 5 has a projected surface 5a on which an image is projected. On the screen 5, an image corresponding to the laser beam 11 emitted from the projector 3 is projected onto the projected surface 5a, and the image is transmitted through the laser beam 11. The laser beam 11 transmitted through the screen 5 is incident on the aspherical mirror 7.

As shown in FIGS. 2 to 4, the screen 5 has a scannable region 6 that can be scanned by the scanning mirror 36 on the projected surface 5a. The scannable area 6 is formed, for example, in a rectangular shape. The scannable region 6 has a scan region 60 on which an image is projected by scanning the laser beam 11. The scan area 60 is formed in a rectangular shape like the scannable area 6. The scanning area 60 is an area in which an image is drawn on the screen 5 after being scanned by the laser beam 11. The scan area 60 is set narrower in the sub-scanning direction than the scannable area 6. The scan area 60 is movable in the sub-scanning direction within the scannable area 6.

The projector 3 is controlled by the control unit 10 in the vehicle display device 1. The control unit 10 controls the amount and color of the laser beam 11 emitted from the projector 3 by driving and controlling the first to third light sources 31 to 33 in the projector 3. The control unit 10 controls the output of the laser beam 11 of each light source, for example, based on the amount of light of the laser beam 11 and the target value of the color.

The control unit 10 drives the scanning mirror 36 as the scanning mirror driving means. The control unit 10 drives the scan mirror 36 to make the scan area 60 movable in the scannable area 6 in the sub-scanning direction. That is, the control unit 10 can move the scanning region 60 in the sub-scanning direction and change the projection position of the image with respect to the windshield 101 by changing the current value flowing through the coil of the stage unit 37.

The control unit 10 drives the scanning mirror 36 so that the target scanning region where the image can be projected at the position corresponding to the eye point 201 of the driver 200 obtained from the vehicle 100 and the scanning region 60 overlap. The eye point 201 is obtained, for example, by a camera, a sensor, or the like that captures the driver 200 and detects the eye point 201. For example, when the eye point 201 moves in the vertical direction, the position of the target scanning area in the sub-scanning direction changes according to the amount of change in the moving direction of the eye point 201. The control unit 10 moves the scanning area 60 upward or downward in the sub-scanning direction so that the target scanning area and the scanning area 60 overlap with each other in accordance with the change in the position of the target scanning area. At this time, if the image drawn in the scanning area 60 should be in the central visual field of the driver 200, the control unit 10 projects the image on the eye point 201 at a position in the central visual field of the driver 200. The scanning mirror 36 is driven so as to be. On the other hand, when the image is intended to be placed in the peripheral visual field of the driver 200, the control unit 10 controls the scanning mirror 36 so that the image is projected on the eye point 201 at a position within the peripheral visual field of the driver 200. To drive.

The control unit 10 drives and controls the scanning mirror 36 to set the width of the scanning region 60 in the sub-scanning direction. The width of the scanning area 60 in the sub-scanning direction is determined by the scanning angle (swing angle) θ [°] in the sub-scanning direction of the scanning mirror 36. The scanning angle θ is formed when the coil of the stage portion 37 receives electric power and the stage portion 37 rotates relative to the scanning mirror 36 with the rotation axis X2 as the center of rotation. Therefore, the control unit 10 periodically changes the current value within a constant fluctuation range so that the energization currents A1 and A2 to the coil have the waveform as shown in FIG. 5, so that the sub-scanning of the scanning region 60 is performed. The width of the direction can be set. The scanning angle θ does not change even if the scanning region 60 moves in the scannable region 6 in the sub-scanning direction when the current value is changed while the fluctuation widths of the energization currents A1 and A2 to the coil are kept constant. .. The scanning angle θ is, for example, about 15 °. The scanning angles θ are equal to each other in the sub-scanning direction about the axis Y. The width of the scanning area 60 is preferably set so that the quality of the image drawn in the scanning area 60 can be maintained.

The aspherical mirror 7 is a reflection mirror. The aspherical mirror 7 is arranged on the optical path between the projector 3 and the screen 5. The aspherical mirror 7 has an aspherical surface formed in a concave shape toward the windshield 101. The aspherical mirror 7 projects the image by reflecting the laser beam 11 transmitted through the screen 5 toward the windshield 101 of the vehicle 100. The aspherical mirror 7 reflects the laser beam 11 and projects an image on the windshield 101 of the vehicle 100. The aspherical mirror 7 in this embodiment is directly fixed to the housing 9.

The housing 9 is assembled with various parts constituting the vehicle display device 1 such as the projector 3 and the aspherical mirror 7, and constitutes a case for accommodating them. The housing 9 is made of an insulating resin material or the like. The housing 9 has a transparent cover 9a on the surface facing the windshield 101. The laser beam 11 reflected by the aspherical mirror 7 irradiates the windshield 101 through the transparent cover 9a.

In the vehicle display device 1 having the above configuration, the control unit 10 drives the scanning mirror 36 to make the scanning area 60 movable in the scannable area 6 in the sub-scanning direction, and to a position corresponding to the eye point 201. The scanning mirror 36 is driven so that the target scanning area on which the image can be projected and the scanning area 60 overlap. For example, when the eye point 201a changes to the eye point 201b (FIG. 6), the scanning region 60 moves downward in the sub-scanning direction, so that the first projection region 103 of the windshield 101 is as shown in FIG. The image projected on is moved to the second projection area 104.

As described above, in the vehicle display device 1 according to the present embodiment, the projector 3 reflects the laser beam 11 from the light source unit 30 in the main scanning direction of the projected surface 5a of the screen 5 while performing sub-scanning. The scanning mirror 36 that scans while reflecting in the direction and the scanning mirror 36 that projects the image on the scanning region 60 that is narrower in the sub-scanning direction than the scannable region 6 that can be scanned by the scanning mirror 36 on the screen 5 are driven. It has a control unit 10 and a control unit 10. The control unit 10 can move the scanning area 60 in the scannable area 6 in the sub-scanning direction by driving the scanning mirror 36, and has an image at a position corresponding to the eye point 201 of the driver 200 obtained from the vehicle 100. The scanning mirror 36 is driven so that the target scanning area on which the image can be projected and the scanning area overlap.

According to the vehicle display device 1 according to the present embodiment having the above configuration, the projection position of the image can be changed without moving the aspherical mirror 7. Further, the aspherical mirror 7 can be fixed to the housing 9, and the angular deviation of the aspherical mirror 7 can be reduced due to vibration of the vehicle 100 or the like. Further, since the motor for driving the aspherical mirror 7 is not required, the cost can be reduced and the driving noise of the motor can be reduced.

Further, in the vehicle display device 1 according to the present embodiment, the moving direction of the eye point 201 and the sub-scanning direction are parallel, and the target scanning area is sub-scanned according to the amount of change in the moving direction of the eye point 201. Since the position in the direction changes, for example, even if the eye point 201 of the driver 200 changes, the scanning region 60 can be moved and the image can be projected at a suitable position.

[Modification example]
In the above embodiment, the projector 3 has three light sources of RGB, but the projector 3 is not limited to this, and may be one light source. Further, the projector 3 combines a plurality of laser beams with the dichroic mirrors 34 and 35 to generate one laser beam, but these optics can be combined with the plurality of laser beams. It is not limited to the system.

Further, in the above embodiment, the control unit 10 sets the width of the scanning area 60 in the sub-scanning direction, but may be configured to change the width of the scanning area 60 according to the content of the image. .. For example, by narrowing the scanning width of the scanning region 60, the brightness of the image can be increased, so that it is possible to call attention to the driver 200.

Further, in the above embodiment, as shown in FIG. 1, a part of the projector 3 is exposed to the outside of the housing 9, but the projector 3 is not limited to this, and the projector 3 may be entirely housed in the housing 9. good.

Further, in the above embodiment, the scannable area 6 is set with respect to the entire surface of the projected surface 5a of the screen 5, but the scannable area 6 is not limited to this, and is, for example, a scannable area in the projected surface 5a. A non-scanning area may be set around 6.

1 Vehicle display device 3 Projector 5 Screen 5a Projected surface 6 Scannable area 7 Aspherical mirror 9 Housing 9a Transparent cover 11 Laser light 30 Light source unit 31 1st light source 32 2nd light source 33 3rd light source 34,35 Dichroic mirror 36 Scanning mirror 37 Stage part 38 Mirror part 60 Scanning area 100 Vehicle 101 Windshield 103 First projection area 104 Second projection area 110 Virtual image 200 Driver 201, 201a, 201b Eye point

Claims (2)

A projector that emits laser light corresponding to the image to be visually recognized by the driver of the vehicle,
A projected member on which the image corresponding to the laser beam emitted from the projector is projected and transmitted through the laser beam.
A reflection mirror that reflects the laser beam transmitted through the projected member and reflects it toward the windshield of the vehicle.
Equipped with
The projector is
With at least one light source that outputs the laser beam,
A scanning mirror that scans while reflecting the laser beam from the light source in the main scanning direction of the projected surface of the projected member and in the sub-scanning direction orthogonal to the main scanning direction.
A scanning mirror driving means for driving the scanning mirror so as to project the image onto a scanning region narrower in the sub-scanning direction than the scannable region that can be scanned by the scanning mirror in the projected member.
Have,
The scanning mirror driving means is
By driving the scanning mirror, the scanning area can be moved in the sub-scanning direction within the scannable area.
The scanning mirror is driven so that the target scanning area where the image can be projected at the position corresponding to the eye point of the driver obtained from the vehicle and the scanning area overlap .
The target scanning area is
The position of the scanning mirror in the sub-scanning direction is changed by determining the scanning angle of the scanning mirror in the sub-scanning direction according to the amount of change in the moving direction of the eye point .
A display device for vehicles characterized by this. The moving direction of the eye point and the sub-scanning direction are parallel .
The vehicle display device according to claim 1.

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