JP2024011013A - Virtual image display device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a virtual image display device for a vehicle which can suppress burying of a virtual image into a front object without increasing a size and cost.

SOLUTION: A virtual image display device for a vehicle, which includes a liquid crystal display 121 for emitting display light of an image, a concave mirror 130 for reflecting the display light and projecting the display light onto a windshield 10, and a control part 150 for controlling formation of an image in the liquid crystal display, and displays the image as a virtual image 20 on a foreground of a vehicle 1 in front of the windshield in a superposed manner, includes a detection part 50 for detecting an object Ob existing in front of the vehicle and an adjustment part 140 for adjusting a reflection angle of the display light to the windshield of the concave mirror, wherein the control part adjusts the reflection angle of the concave mirror by the adjustment part and moves the position of the virtual image so that the virtual image is not superposed on the object, when a second distance L2 between an eye point EP of a viewer and the object is equal to or less than a first distance L1 between the eye point and the virtual image.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present disclosure relates to a virtual image display device for a vehicle.

As a virtual image display device for a vehicle, for example, one described in Patent Document 1 is known. The vehicle virtual image display device (image display system) of Patent Document 1 includes a display section, a projection section (mirror), a display control section, and the like.

The display control unit displays the virtual image by determining the projection distance to the virtual image in front according to the vehicle speed and the angle of depression so that the projection position of the virtual image is in a displayable area (an area where there are no road surfaces or objects in front). By doing so, the virtual image is prevented from being projected as if it were buried (entered) into the road surface, objects in front, etc.

In Patent Document 1, in order to adjust the projection distance to the virtual image, the optical path length from the display section to the windshield is changed. Specifically, the set position of the display section is adjusted by the control drive section to adjust the projection distance to the virtual image. The beam is moved in the direction of emission. In addition, in Patent Document 1, in order to adjust the angle of depression, the display position of the virtual image is changed on the display surface of the display section.

JP2019-219547A

However, in order to adjust the projection distance, the setting position of the display section is moved by the control drive section, which requires a space for movement, which increases the size and cost of the entire device. Put it away. In addition, since the display position of the image on the display surface of the display unit is changed in order to adjust the angle of depression, it is necessary to set the display surface of the display unit relatively large, which also increases the size of the entire device. This results in an increase in costs.

In view of the above-mentioned problems, an object of the present disclosure is to provide a virtual image display device for a vehicle that can prevent a virtual image from filling a front object without increasing the size or cost.

The present disclosure employs the following technical means to achieve the above object.

In the present disclosure, a display unit (121) that emits image display light;
a reflecting section (130) that reflects the display light and projects it onto a projection member (10) located in front of the viewer;
A control unit (150) that controls image formation on the display unit,
A virtual image display device for a vehicle that displays an image as a virtual image (20) superimposed on the foreground of a vehicle (1) in front of a projection member,
a detection unit (50) that detects an object (Ob) present in front of the vehicle;
An adjustment unit (140) that adjusts the reflection angle of the display light with respect to the projection member of the reflection unit,
The control unit prevents the virtual image from overlapping the object when the second distance (L2) from the viewer's eye point (EP) to the object is less than or equal to the first distance (L1) from the eye point to the virtual image. The adjustment section adjusts the reflection angle of the reflection section to move the position of the virtual image.

According to the present disclosure, the adjustment unit adjusts the reflection angle of the reflection unit to prevent the virtual image from overlapping the object. Therefore, compared to the case where the display section is moved using a control drive unit as in Patent Document 1, or the case where the display position of the image is changed on the display surface of the display section, it is possible to avoid an increase in size or cost. , it is possible to suppress the virtual image from being buried in the object in front.

It should be noted that the reference numerals in parentheses for each of the above-mentioned means indicate the correspondence with specific means described in the embodiment described later.

FIG. 1 is an explanatory diagram showing the overall configuration of a head-up display device in a first embodiment. It is a flowchart which shows the control point when suppressing filling of a virtual image. It is an explanatory view showing a first distance and a second distance. It is an explanatory view showing that the upper display image of the first embodiment is moved (during follow-up travel). It is an explanatory view showing that the upper display image of the first embodiment is moved (at the time of turn-by-turn). It is an explanatory view showing that the upper display image of a modification is moved (during follow-up travel). It is an explanatory view showing that the upper display image of a modification is moved (at the time of turn-by-turn).

Hereinafter, a plurality of embodiments for carrying out the present disclosure will be described with reference to the drawings. In each form, parts corresponding to matters explained in the preceding form may be given the same reference numerals and redundant explanation may be omitted. When only a part of the configuration is described in each form, the other forms previously described can be applied to other parts of the structure. Not only combinations of parts that specifically indicate that combinations are possible in each embodiment, but also partial combinations of embodiments even if it is not explicitly stated, as long as there is no particular problem with the combination. It is also possible.

(First embodiment)
A virtual image display device for a vehicle according to a first embodiment will be explained based on FIGS. 1 to 5. As shown in FIG. 1, the vehicular virtual image display device is a device that projects an image of a display device 120 (liquid crystal display 121) onto the windshield 10 in front of the driver (viewer) of the vehicle 1. The windshield 10 corresponds to the projection member of the present disclosure.

That is, the virtual image display device for a vehicle projects display light representing an image emitted from the display device 120 onto the projection position 10a of the windshield 10 of the vehicle 1. The display light is light indicated by a chain double-dashed arrow from the display device 120 to the windshield 10 in FIG. The vehicular virtual image display device displays a virtual image 20 superimposed on the forward extension of the vehicle 1 of the line connecting the driver and the projection position 10a, that is, in the foreground of the road on which the vehicle is traveling, so that the driver can see it. It has become. Such a virtual image display device for a vehicle is called a head-up display (Head-Up Display) device, and hereinafter referred to as “HUD device 100”.

In the HUD device 100 of the present embodiment, the virtual image 20 is, for example, an image indicating vehicle information during normal driving (vehicle speed value, AT shift lever position, etc.), or an image indicating vehicle information during normal driving (vehicle speed value, AT shift lever position, etc.), or an image indicating automatic follow-up driving and speed maintenance driving during high-speed driving ( ACC), or an image indicating a change of course (turn-by-turn) when guiding a destination by a car navigation device.

Note that the windshield 10 is a shield on the front side of the vehicle 1, and uses, for example, a laminated glass formed from two pieces of glass and an interlayer film provided in between. The windshield 10 has a curvature such that the interior side of the vehicle 1 is a concave surface when viewed from above the vehicle 1 and from the side of the vehicle 1, and has the same effect as a concave mirror to improve the display image. It is now possible to enlarge the image and display it further away.

The HUD device 100 includes a detection section 50, a housing 110, a display device 120, a concave mirror 130, an adjustment section 140, a control section 150, and the like.

The detection unit 50 is a part that detects an object Ob present in front of the vehicle 1. The object Ob is, for example, a vehicle in front of the road on which the vehicle 1 is traveling, a wall on the side of the road, a road surface, or the like. As a configuration of the detection unit 50, for example, a navigation device that acquires road information (traffic jam information, etc.) related to the object Ob, a front camera that directly detects the object Ob, a front sensor, or the like is used. The detection unit 50 is configured to output information about the detected object Ob (presence or absence of the object Ob, distance to the object Ob, etc.) to the control unit 150.

The housing 110 is a case member that houses the display device 120, the concave mirror 130, the adjustment section 140, the control section 150, and the like therein, and has, for example, a rectangular parallelepiped shape. An opening 111 is formed on the upper side of the housing 110 (on the windshield 10 side) so that display light from the display device 120 can be emitted (passed through). A translucent dustproof sheet is provided in the opening 111 to prevent dirt, dust, etc. from entering the housing 110. The housing 110 is arranged within the instrument panel of the vehicle 1. Note that an instrument panel opening through which display light passes is also formed on the upper surface of the instrument panel. The control unit 150 may be provided outside the housing 110, as shown in FIG.

The display device 120 includes a liquid crystal display 121, a backlight 122, and the like.

The liquid crystal display 121 is illuminated by light from a backlight 122 to display a predetermined image on a display surface 121a, and is driven and controlled (image formation processing) by a control unit 150. . The liquid crystal display 121 is, for example, a TFT liquid crystal display using a thin film transistor (TFT). The liquid crystal display 121 corresponds to the display section of the present disclosure.

The backlight 122 is disposed on the back side of the liquid crystal display 121 (on the opposite side of the display surface 121a), and emits light when energized (supplied with power) to provide light for displaying images to the liquid crystal display 121. It serves as a light source for illumination. The backlight 122 uses, for example, a light emitting diode (LED). A plurality of light emitting diodes are provided and arranged in a grid pattern. The light emitting state of the backlight 122 is controlled by the control unit 150, and the backlight 122 emits light along the optical axis toward the liquid crystal display 121.

The liquid crystal display 121 is configured to emit display light representing an image toward a concave mirror 130 on the opposite side from the backlight 122, using light emitted from the backlight 122. In this embodiment, the surface of the liquid crystal display 121 that emits display light (display surface 121a) is oriented in the vertical direction, for example, and the optical axis of the display light is oriented in the longitudinal direction of the vehicle 1 (the emission direction is (facing the front side of 1). As mentioned above, the image formed by the liquid crystal display 121 is an image showing vehicle information during normal driving (vehicle speed value, AT shift lever position, etc.), or an image showing vehicle information during normal driving (vehicle speed value, AT shift lever position, etc.), or an image showing automatic follow-up driving and speed maintenance driving during high-speed driving ( ACC), or an image indicating a change of course (turn-by-turn) when guiding a destination by a car navigation device.

The concave mirror 130 is a mirror that magnifies the image display light from the liquid crystal display 121, and the reflective surface of the concave mirror 130 is arranged to face the liquid crystal display 121 and the projection position 10a of the windshield 10. The concave mirror 130 is configured to reflect display light emitted from the liquid crystal display 121 to the projection position 10a of the windshield 10 through the opening 111 of the housing 110. Concave mirror 130 corresponds to the reflecting section of the present disclosure.

The concave mirror 130 has a surface (reflecting surface) curved toward the concave side, and has, for example, a quadrilateral (rectangular shape) that is laterally elongated in the left-right direction of the vehicle 1 . The concave mirror 130 is supported and rotatable by a rotation shaft 131 extending in the left-right direction of the vehicle 1, and the inclination angle of the concave mirror 130 shown in FIG. 1 is adjusted by the control unit 150. .

The lower end of the concave mirror 130 is connected to an arm 141 of an adjustment section 140, which will be described later. The concave mirror 130 can be rotated clockwise (forward direction) or counterclockwise (reverse direction) in FIG. It is supposed to be done.

By rotating the concave mirror 130, the reflection angle of the display light is adjusted, the vertical position of the image projected onto the windshield 10 is changed, and the vertical position of the virtual image 20 is accordingly changed. That will happen. When the concave mirror 130 is rotated clockwise, the position of the virtual image 20 is moved upward with respect to the windshield 10. Further, when the concave mirror 130 is rotated counterclockwise, the position of the virtual image 20 is moved downward with respect to the windshield 10.

The adjustment unit 140 is a device that drives (rotates) the concave mirror 130 to adjust the reflection angle of the display light of the concave mirror 130 with respect to the windshield 10 . The adjustment unit 140 has an arm 141 that is slid, for example, in the vertical direction of the vehicle 1 by a motor. The motor is, for example, a synchronous motor (step motor) that operates in synchronization with an input pulse voltage.

The arm 141 is a rod-shaped member that connects the motor side and the concave mirror 130. One end of the arm 141 is fixed to a sliding member that is slid in the vertical direction of the vehicle 1 by a motor, and the other end of the arm 141 is connected to, for example, the lower end of the concave mirror 130. There is. The concave mirror 130 and the arm 141 form a link mechanism. In other words, the arm 141 is slid by the sliding member to rotate the concave mirror 130.

As the arm 141 slides toward the concave mirror 130, the concave mirror 130 rotates counterclockwise, and the inclination of the concave mirror 130 with respect to the vertical direction increases (tilts in the horizontal direction). Conversely, the more the arm 141 slides to the side opposite to the concave mirror 130, the more the concave mirror 130 rotates clockwise and the tilt of the concave mirror 130 becomes smaller (stands vertically). Further, the smaller the sliding range of the arm 141, the smaller the amount of change in the tilt of the concave mirror 130, and conversely, the larger the sliding range of the arm 141, the larger the amount of change in the tilt of the concave mirror 130.

The control unit 150 performs display control related to image processing (image formation) on the liquid crystal display 121, and controls the angle of the concave mirror 130 (position movement of the virtual image 20) using the adjustment unit 140 according to information about the object Ob from the detection unit 50. control) (details will be described later).

The HUD device 100 is configured as described above, and the operation and effects of the HUD device 100 will be explained below with reference to FIGS. 2 to 5.

When the HUD device 100 is turned on (ignition on), the control unit 150 acquires peripheral information regarding the object Ob from the detection unit 50 in step S100 in FIG. As described above, the object Ob has been described as a vehicle ahead, a wall at the end of the road, a road surface, etc., but here, as a specific example, it will be described as a vehicle ahead as shown in FIGS. 3 to 5.

The control unit 150 determines, from the information on the object Ob obtained from the detection unit 50, whether there is a vehicle ahead and the distance from the driver's eye point EP to the vehicle ahead when there is a vehicle ahead (hereinafter referred to as second distance L2). Calculate. Further, the control unit 150 knows the first distance L1 from the eye point EP to the virtual image 20 in advance. The first distance L1 is a distance uniquely determined by the distance from the liquid crystal display 121 to the projection position 10a of the windshield 10 via the concave mirror 130.

Here, as shown in FIG. 4A, for example, in normal times, the control unit 150 rotates the concave mirror 130 counterclockwise to display the virtual image 20 in the lower area of the windshield 10. , displays the lower display image 20a. The lower display image 20a is, for example, an image showing vehicle information, such as a vehicle speed value (such as "60 km/h") and a shift lever position (such as "D").

Further, as shown in FIG. 4A, for example, when the controller 150 is driving in ACC, the control unit 150 rotates the concave mirror 130 clockwise to rotate the upper area of the windshield 10 (for example, the lower area of the vehicle in front). An upper display image 20b is displayed as the virtual image 20 in place of the lower display image 20a. The upper display image 20b is, for example, a mark image (a mark imitating the vehicle ahead, the road the vehicle is traveling on, etc.) in ACC driving. Further, as shown in FIG. 5A, for example, when the navigation device is performing destination guidance, the control unit 150 displays an arrow image 20b1 (turn-by-turn) indicating a course change as the upper display image 20b. It may also be displayed.

In this way, in the HUD device 100 of this embodiment, the display content and display position of the virtual image 20 are adjusted according to the driving conditions.

Next, in step S110 of FIG. 2, the control unit 150 determines whether the second distance L2 is less than or equal to the first distance L1. The fact that the second distance L2 is less than or equal to the first distance L1 indicates that the virtual image 20 is buried (entered) inside the vehicle ahead, as shown in FIG. If the virtual image 20 is buried in the vehicle ahead, the driver's focus adjustment function becomes confused, leading to discomfort (brain fatigue).

Therefore, if an affirmative determination is made in step S110, the control unit 150 causes the adjustment unit 140 to adjust the reflection of the concave mirror 130 so that the image (virtual image 20) does not overlap with the vehicle ahead by rotating the concave mirror 130 in step S120. The display position of the image (virtual image 20) with respect to the windshield 10 is moved by adjusting the angle.

Then, in step S130, the control unit 150 causes the windshield 10 to display the image with the position moved.

Specifically, as shown in FIG. 4(b), when the vehicle ahead approaches the vehicle 1 and the second distance L2 becomes less than or equal to the first distance L1, for example, the upper display image 20b is buried in the vehicle ahead. If so, the upper display image 20b is moved downward so that there is no filling (overlapping). Alternatively, as shown in FIG. 5(b), for example, if the turn-by-turn arrow image 20b1 is buried in the vehicle ahead, the arrow image 20b1 is moved downward to prevent it from being buried (overlapping). do.

Note that depending on the position of the vehicle ahead and the position of the image, the lower display image 20a may be moved upward, for example, to avoid being buried in the vehicle ahead.

On the other hand, if a negative determination is made in step S110, the control unit 150 performs normal display in step S140. The normal display is the original display of the lower display image 20a or the upper display image 20b (arrow image 20b1) without movement of the display position, as described in steps S120 and S130.

As described above, in the present embodiment, the control unit 150 controls when the second distance L2 from the driver's eye point EP to the object Ob in front is equal to or less than the first distance L1 from the eye point EP to the virtual image 20. The adjustment unit 140 adjusts the reflection angle of the concave mirror 130 to move the position of the virtual image 20 so that the virtual image 20 does not overlap the object Ob.

This results in an increase in size and cost compared to the case where the display section is moved using a control drive section or the display position of the image is changed on the display surface of the display section as in Patent Document 1. It is possible to suppress the virtual image 20 from being buried in the object Ob in front of the object Ob.

Further, the adjustment unit 140 adjusts the reflection angle of the display light by rotating the concave mirror 130 around the rotation axis 131 in the horizontal direction, and the position of the virtual image 20 is adjusted by the adjustment unit 140. It is set to move in the vertical direction. Thereby, the position of the virtual image 20 can be easily moved in the vertical direction.

(Modified example of the first embodiment)
In a modification of the first embodiment, the concave mirror 130 is provided with another rotation axis in the vertical direction of the concave mirror 130 in addition to the rotation axis 131 in the horizontal direction, so that the concave mirror 130 can be rotated on two axes by the adjustment unit 140. It is said that In this case, by rotating the concave mirror 130 around the other rotation axis, it is possible to move the displayed image not only in the vertical direction but also in the horizontal direction.

Therefore, for example, as shown in FIG. 6(b) and FIG. 7(b), the upper display position is the same and the upper display image 20b or the arrow image 20b1 is moved in the left-right direction (rightward in this case). Therefore, it is possible to avoid the virtual image 20 from being buried in the vehicle in front.

(Second embodiment)
In the second embodiment, after moving the position of the virtual image 20, the control unit 150 adjusts the image on the liquid crystal display 121 to compensate for image distortion that occurs depending on the position of the display light projected onto the windshield 10. Correct by

In the windshield 10, when the position of the image is moved, distortion of the image (virtual image 20) may occur because the curvature of the windshield 10 differs slightly depending on the movement position. Therefore, the control unit 150 grasps the image distortion for each position of the windshield 10 in advance, and applies reverse distortion to the image on the liquid crystal display 121 to cancel the distortion that may occur.

Thereby, distortion of the image (virtual image 20) on the windshield 10 caused by moving the position of the virtual image 20 can be eliminated.

(Other embodiments)
The disclosure in this specification, drawings, etc. is not limited to the illustrated embodiments. The disclosure includes the illustrated embodiments and variations thereon by those skilled in the art. For example, the disclosure is not limited to the combinations of parts and/or elements illustrated in the embodiments. The disclosure can be implemented in various combinations. The disclosure may have additional parts that can be added to the embodiments. The disclosure includes those in which parts and/or elements of the embodiments are omitted. The disclosure encompasses any substitutions or combinations of parts and/or elements between one embodiment and other embodiments. The disclosed technical scope is not limited to the description of the embodiments. The technical scope of some of the disclosures is indicated by the description of the claims, and should be understood to include equivalent meanings and all changes within the scope of the claims.

Further, in each of the above embodiments, the windshield 10 of the vehicle 1 is used as a projection member for display light emitted from the liquid crystal display 121 (display device 120), but the present invention is not limited to this, and the HUD device 100 may be provided with a dedicated projection member. It may also be used as a combiner or the like.

Further, in each of the above embodiments, the liquid crystal display 121 (TFT liquid crystal display) is used as the display device 120, but instead of this, another type of display such as an organic EL display may be used. good.

Further, in each of the above embodiments, the concave mirror 130 is used as the reflecting section, but another reflecting section may be provided between the display device 120 and the concave mirror 130. The other reflecting portion can be any one of a plane mirror, a concave mirror, and a convex mirror.

1 Vehicle 10 Windshield (projection member)
20 Virtual image 20a Guide route 50 Detection unit 100 Head-up display device (virtual image display device for vehicle)
121 Liquid crystal display (display section)
130 Concave mirror (reflection part)
131 Rotation axis 140 Adjustment section 150 Control section EP Eye point Ob Object L1 First distance L2 Second distance

Claims (3)

a display unit (121) that emits image display light;
a reflecting section (130) that reflects the display light and projects it onto a projection member (10) located in front of a viewer;
a control unit (150) that controls formation of the image on the display unit,
A virtual image display device for a vehicle that displays the image as a virtual image (20) superimposed on the foreground of the vehicle (1) in front of the projection member,
a detection unit (50) that detects an object (Ob) present in front of the vehicle;
an adjustment unit (140) that adjusts a reflection angle of the display light of the reflection unit with respect to the projection member;
The control unit is configured to cause the virtual image to be configured to A virtual image display device for a vehicle, wherein the reflection angle of the reflection section is adjusted by the adjustment section so that the virtual image does not overlap with an object, and the position of the virtual image is moved. The adjustment unit is configured to adjust the reflection angle of the display light by rotating the reflection unit around a horizontal rotation axis (131),
The virtual image display device for a vehicle according to claim 1, wherein the position of the virtual image is moved in the vertical direction by the adjustment section. After moving the position of the virtual image, the control unit corrects distortion of the image that occurs depending on the position of the display light projected onto the projection member by adjusting the image of the display unit. The virtual image display device for a vehicle according to claim 1 or 2.

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