JP2022114280A - On-vehicle display device - Google Patents

Abstract

To provide an on-vehicle display device capable of reducing a burden on an occupant who adjusts focus for visually identifying an object in a virtual image and the foreground.SOLUTION: An on-vehicle display device 1 displays beneficial information for driving a vehicle as a virtual image i at the front of an occupant. The on-vehicle display device 1 comprises: an image display section 10 which forms a display image to be a base of the virtual image i and emits display light 22 according to the display image; a virtual image forming optical system 12 which guides the display light 22 to an eye 5 of the occupant so that the same can visually identify the virtual image of the display image; and an optical plate 15 which is arranged on an optical path of the display light 22 and has a power adjustment region 30 with power varied in an outward radial direction perpendicular to an optical axis.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to an in-vehicle display device, and more particularly to an in-vehicle display device that displays information useful for driving a vehicle in front of a passenger.

A head-up display device as an in-vehicle display device includes an image display unit that forms a display image that is the source of a virtual image and emits display light corresponding to the display image, and a combiner that serves as a display screen for projecting the display image. , information useful for driving the vehicle is displayed as a virtual image in front of the occupant (for example, at a position about 2 m away from the occupant). This virtual image is displayed superimposed on the foreground of the vehicle seen through the windshield (windshield). (e.g., a car running on the Therefore, when the occupant shifts the visual recognition target from the virtual image to the foreground object, or from the foreground object to the virtual image, it is necessary to adjust the focus (focus adjustment) again using the accommodation power of the eyes. occur.

Repeated accommodation contributes to accommodative asthenopia. In addition, when the object in the foreground and the virtual image are far apart and the parallax is large, the recognition tends to be deteriorated. Therefore, it is desirable to display the virtual image displayed in front of the passenger at a position as close to the object in the foreground as possible. However, in order to realize this, it is necessary to increase the length of the optical path between the image display unit and the combiner in order to display the virtual image farther than the current position, which increases the size and complexity of the device. I invite you.

As a technique for changing the display position of the virtual image, as disclosed in Patent Document 1 below, a mirror provided on the optical path is configured to be movable along the optical path, and the mirror is moved. It is known to change the display position of a virtual image by changing the optical path length of display light.

JP 2017-226292 A

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-described problems, and to provide an in-vehicle display device capable of reducing the burden of adjusting the focus on the occupant when visually recognizing a virtual image and an object in the foreground. do.

Accordingly, the present invention provides an in-vehicle display device that is mounted in a vehicle and displays useful information for driving the vehicle in front of the occupant,
an image display unit that forms a display image serving as a virtual image and emits display light according to the display image;
a virtual image forming optical system that guides the display light to the eyes of the occupant and allows the occupant to visually recognize a virtual image of the display image;
an optical plate provided on the optical path of the display light and/or between the occupant's eye and the virtual image, and comprising a power adjustment area whose power changes outward in the direction perpendicular to the optical axis;
characterized by comprising

According to the present invention, the optical plate provided on the optical path of the display light and/or between the eyes of the occupant and the virtual image has the effect of extending the depth of field, so that the virtual image is in focus when visually recognized. and/or the depth of field considered in focus when viewing an object in the foreground of the vehicle is extended so that the virtual image and objects in the foreground are visible When doing so, it is possible to reduce the burden on the occupant to adjust the focus.

In the present invention, the virtual image forming optical system includes a reflecting mirror for reflecting the display light emitted from the image display unit and a transparent display screen, and the display light reflected by the reflecting mirror is further a display screen reflective to the passenger side,
The optical plate can be provided between the reflecting mirror and the image display section.
In this way, the display position of the virtual image can be extended in the vehicle front-rear direction due to the effect of extending the depth of field by the optical plate.

In the present invention, the virtual image forming optical system may also include a reflecting mirror that reflects the display light emitted from the image display unit, and a transparent display screen, wherein the display light reflected by the reflecting mirror is and a display screen that reflects to the passenger side,
The optical plate can be provided on the virtual image side of the display screen.
In this way, the effect of extending the depth of field by the optical plate makes it possible to extend the depth of field when viewing the foreground of the vehicle in the longitudinal direction of the vehicle. , the distant scenery (the foreground of the vehicle) can be easily recognized.

Here, according to the invention, the display screen can be the windshield of the vehicle or a combiner separate from the windshield.

Further, in the present invention, the virtual image forming optical system includes the optical plate provided between the image display unit and the passenger,
The optical plate may be configured to include the power adjustment area in which a plus power is set in each area through which the line of sight of the occupant passes, and the power changes toward the outer side in the direction orthogonal to the optical axis.
With this configuration, the display image displayed on the image display unit can be visually recognized as a virtual image displayed on the front side of the vehicle from the actual display image due to the effect of extending the depth of field by the optical plate. Therefore, the difference (distance) between the position of the virtual image and the position of the object included in the foreground of the vehicle can be reduced.

FIG. 1 is a diagram showing a schematic configuration of a head-up display device as an in-vehicle display device according to the first embodiment. FIG. 2(A) is a diagram showing the optical plate of FIG. 1, and FIG. 2(B) is a diagram schematically showing the change in power along the direction perpendicular to the optical axis of the optical plate. FIG. 3(A) is a diagram schematically showing a change in power different from FIG. 2(B), and FIG. 3(B) is a schematic showing change in power different from FIGS. 2(B) and 3(A). It is a schematic diagram. FIG. 4 is a diagram showing a schematic configuration of a head-up display device as an in-vehicle display device according to the second embodiment. FIG. 5(A) is a diagram showing the optical plate of FIG. 4, and FIG. 5(B) is a diagram schematically showing the change in power along the direction perpendicular to the optical axis of the optical plate. FIG. 6 is a diagram showing a schematic configuration of an in-vehicle display device according to the third embodiment. FIG. 7A is a diagram showing the transmissive panel of FIG. 6, and FIG. 7B is a diagram schematically showing the change in power along the direction perpendicular to the optical axis of the transmissive panel.

<First embodiment>
Next, a head-up display device as an in-vehicle display device according to the first embodiment will be described with reference to the drawings. In FIG. 1, reference numeral 1 denotes a head-up display device, which displays a virtual image i on an extension of a line connecting the eyes 5 of an occupant sitting in the driver's seat of an automobile and a display screen 18 .

The head-up display device 1 includes an image display unit 10 that forms a display image that is the source of the virtual image, a virtual image forming optical system 12 that allows the occupant to visually recognize the virtual image of the display image, and a virtual image that is displayed within a range having a certain width. and an optical plate 15 for allowing Most of the parts constituting the head-up display device 1 are housed inside the instrument panel 3 near the lower end of the windshield 2 .

The image display unit 10 is composed of, for example, a small liquid crystal panel equipped with a backlight as a light source. Based on information received from a control unit (not shown), the image display unit 10 forms an image showing the values of various gauges such as a speedometer and a fuel gauge, a map image in a navigation system, etc., as display images. A display image is displayed on the display surface 10 a of the image display unit 10 . By transmitting the light from the backlight through the liquid crystal panel, the display surface 10a emits the display light 22 having the information of the display image.
As the image display unit 10, a projector or the like that displays an image by scanning laser light in two-dimensional directions can be appropriately adopted.

The virtual image forming optical system 12 includes a projection lens 14, a reflecting mirror 16, and a display screen 18, and guides the display light 22 emitted from the image display unit 10 to the eyes 5 of the occupant to display to the occupant. Make the virtual image of the image visible. In FIG. 1, the reference optical axis L is the path of the light ray at the center of the virtual image i formed based on the display light 22 .

The projection lens 14 faces the display surface 10a of the image display unit 10 in front of the image display unit 10, and is arranged so that the optical axis of the projection lens 14 coincides with the reference optical axis L, thereby displaying the image. The display light 22 emitted from the unit 10 is projected onto the reflecting mirror 16 . The projection lens 14 may be configured by a single lens, or may be configured by combining a plurality of lenses.

The reflecting mirror 16 is a mirror that reflects the display light 22 transmitted through the projection lens 14 toward the display screen 18, and is arranged with the concave surface 16a, which is the reflecting surface, facing the projection lens 14 side. It is The display light 22 emitted from the image display unit 10 is enlarged by the projection lens 14 and the reflecting mirror 16, passes through the opening 4 formed in the instrument panel 3, and reaches the display screen 18 positioned above the instrument panel 3. projected.

The display screen 18 is a transparent concave mirror or plane mirror configured by a half mirror such as a combiner. It is erected on the instrument panel 3 and reflects display light 22 from the reflecting mirror 16 toward the rear side of the vehicle. The display screen can also be constructed from the windshield 2 of the vehicle.

The display light 22 reflected by the display screen 18 is guided to the eyes 5 of the passenger sitting in the driver's seat and their surroundings. Based on the display light 22 , the occupant can observe the virtual image i on the front side of the vehicle on the extension of the line connecting the occupant's eye 5 and the display screen 18 . Here, the position of the virtual image i that can be virtually visually recognized without passing through the optical plate 15 is the position indicated by i ₀ in FIG. Further, according to the display screen 18, which is a half mirror, the external light transmitted through the display screen 18 is also guided to the eye 5 of the passenger and its peripheral portion. Therefore, the passenger can also observe the foreground of the vehicle through the display screen 18, and as a result, the virtual image at the position _i0 can be superimposed on the foreground of the vehicle and observed.

Here, in this embodiment, the optical plate 15 is arranged between the reflecting mirror 16 and the projection lens 14 . The optical plate 15 is a lens having a width in the focal length, and is arranged so that the optical axis of the optical plate 15 coincides with the reference optical axis L. As shown in FIG.

In this example, as shown in FIG. 2A, the optical plate 15 is a lens whose front surface (reflecting mirror side) 27 and rear surface (image display unit side) 28 are both convex. The shape is rotationally symmetrical about the optical axis passing through the center O (the base point O ₁ on the rear surface 28 and the base point O ₂ on the front surface 27). The optical plate 15 has a power of S _{0 diopter} at the optical center as shown in FIG. A power adjustment region 30 (Fig. 2 ( B) see) is formed.

An example of the aspherical component added to the lens surface is the aspherical component represented by Σ{A _n r ⁿ }. where r: distance from the optical axis, A _n : aspheric coefficient, n: positive integer. Σ{ } is a symbol indicating the sum in { }. For example, the aspheric component may be represented by A ₄ r ⁴ +A ₆ r ⁶ +A ₈ r ⁸ +A ₁₀ r ¹⁰ or may be represented by A ₃ r ³ . The aspherical coefficient A _n for specifying the aspherical component can be appropriately determined by ray-tracing simulation or the like so as to obtain desired optical characteristics (change in power).
The optical plate 15 may not be a lens in which both the front surface 27 and the rear surface 28 are convex as shown in FIG. It is also possible for the surface to be concave.

By providing the optical plate ₁₅ configured in this way, as shown in FIG. It is possible to extend to the front side of the vehicle (foreground side of the vehicle) from the position i ₀ of the virtual image that can be visually recognized without touching it.

Therefore, according to the head-up display device 1 of the present embodiment, as shown in FIG. 1, the difference (parallax) between the virtual image i and the object k included in the foreground of the vehicle becomes small. It is possible to reduce the burden of adjusting the focus when the occupant, who has been in the foreground, shifts his line of sight to the object k included in the foreground.

As shown in FIG. 2B, the optical plate 15 of this example has a power that gradually changes from the optical center O toward the edge of the optical plate. can be changed as appropriate. For example, as shown in FIG. 3A, the power of the lens central region 31 within the distance r ₀ from the optical center O is set to a constant power S ₀ , and the region outside the lens central region 31 is set to the positive side of S ₀ . It is also possible to set it as a power adjustment area 30 in which the power is changed. Further, as shown in FIG. 3B, it is possible to form an area 32 where the power is maintained at a predetermined value (the power does not change) outside the power adjustment area 30 . Further, in this example, the optical plate 15 is provided separately from the projection lens 14, but the optical plate 15 is integrally formed with the projection lens 14, and the projection lens 14 is provided with the power adjustment region to achieve the above-described configuration. It is also possible to realize the frequency distribution shown.

Further, in the power adjustment region 30 of the optical plate 15, by changing the power toward the outside in the direction perpendicular to the optical axis r (peripheral side of the optical plate) toward the negative side, the virtual image i is moved closer to the front side (position closer to the occupant). It is also possible to display

<Second embodiment>
Next, a head-up display device 1B according to a second embodiment will be described.
As shown in FIG. 4, the head-up display device 1B includes an image display unit 10 that forms a display image that is the basis of a virtual image, a virtual image forming optical system 12 that allows a passenger to visually recognize the virtual image of the display image, and a depth of field. and an optical plate 15B extending from the . Among these components, components common to the head-up display device 1 described above are denoted by the same reference numerals, and descriptions thereof are omitted.

In the head-up display device 1 according to the first embodiment, the optical plate is arranged between the reflecting mirror 16 and the projection lens 14, whereas in the head-up display device 1B of this example, the display screen An optical plate 15B is arranged on the virtual image side of 18 .

In this example, as shown in FIG. 5A, the optical plate 15B is a lens having a concave front surface 27 and a rear surface 28, and the front surface 27 and the rear surface 28 are the optical center O (at the rear surface 28, the base point O ₁ , the front surface 27 has a rotationally symmetrical shape around the optical axis passing through the base point O ₂ ). As shown in FIG. 5B, the optical plate 15B has a power of S ₀ diopter at the optical center (S ₀ is a negative value in this example, but may be zero or a positive value in some cases). A power adjustment region 30 (Fig. 5 ( B) see) is formed. It should be noted that the optical plate 15B may have a convex shape on one side and a concave shape on the other side.

In the head-up display device 1B provided with the optical plate 15B configured in this way, the depth of field G when visually recognizing the foreground of the vehicle is extended to the front side of the vehicle (occupant It can be extended farther from the perspective of the vehicle), and for example, even when the focus is on the virtual image i, there is an effect that the distant scenery (object k included in the foreground of the vehicle) can be easily recognized. Therefore, when visually recognizing the virtual image i and the object k in the foreground, the burden of adjusting the focus on the passenger can be reduced.

In this example, the optical plate 15B is provided separately from the display screen 18, but the optical plate 15B and the display screen 18 can be configured integrally. In this example, the optical plate 15B is provided in place of the optical plate 15 described above, but it is also possible to provide a head-up display device provided with both the optical plates 15 and 15B.

In addition, in the power adjustment region 30 of the optical plate 15B, when the power is changed to the positive side toward the outer side of the optical axis orthogonal direction r (peripheral side of the optical plate), the depth of field is increased to the rear side of the vehicle (occupant ), it is possible to obtain the effect of making it easier to see the virtual image in front even when looking at a distant view (foreground of the vehicle).

<Third Embodiment>
Next, an in-vehicle display device 1C according to a third embodiment will be described.
As shown in FIG. 6, the in-vehicle display device 1C is attached in front of the passenger and has a case 40 formed integrally with the instrument panel 3 of the vehicle. and a control unit (not shown).

The display 43 is composed of, for example, a liquid crystal panel equipped with a backlight as a light source, and is arranged with its display surface 43a directed toward the rear side of the vehicle. The display 43 displays an image such as a speedometer on the display surface 43a based on the information received by the control unit. By transmitting the light from the backlight through the liquid crystal panel, the display surface 43a emits display light 22 having information of a display image (image of a speedometer or the like).

The transmissive panel 50 is arranged to face the display surface 43a of the display 43, and transmits the display light 22 emitted from the display surface 43a of the display 43 to the rear side of the vehicle. The display light 22 transmitted through the transmissive panel 50 is transmitted through the opening 41 of the case 40 to the eye 5 of the passenger sitting in the driver's seat and its surroundings. As a result, a virtual image i representing a speedometer or the like is displayed on an extension of the line connecting the eye 5 of the occupant and the display 43 .

Here, the transmissive panel 50 is a lens in which a positive power is set in each region through which the passenger's line of sight passes, and which has a wide focal length. As shown in FIG. 7A, the transmissive panel 50 is a lens with a front surface (passenger side) 51 and a rear surface (image display unit side) 52 having a convex shape. The shape is rotationally symmetrical about the optical axis passing through the base point O ₁ on the rear surface 52 and the base point O ₂ on the front surface 51 . The transmissive panel 50 has a power of S2 diopters ₍ where S2 is a positive value) at the optical center as shown in _FIG . A power adjustment region 30 is formed in which the power changes to the positive side toward the outer side (periphery side) of the direction perpendicular to the optical axis r.

A normal lens has one focal length, but the transmissive panel 50 of this example has a range of focal lengths. In other words, when light parallel to the optical axis is incident on a normal lens, the light is condensed at one point on the optical axis. Light is focused in a range that has a width up to a certain point. For this reason, on the transmissive panel 50, a display image as an object is observed and formed as a virtual image within a range having a certain width.

According to the in-vehicle display device 1C having the transmissive panel 50 configured as described above, as shown in FIG. ), a virtual image i representing a speedometer or the like is displayed within a range having a certain width.
Therefore, according to the in-vehicle display device 1C of the present embodiment, the difference (distance) between the position of the virtual image i indicating the speedometer or the like and the position of the object included in the foreground of the vehicle is reduced. When the occupant shifts his or her line of sight to the object k included in the foreground, the burden of adjusting the focus can be reduced.

In addition, in the power adjustment area 30 in the transmissive panel 50, by changing the power toward the outside of the optical axis orthogonal direction r (peripheral side of the optical plate) toward the negative side, the virtual image i is moved closer to the front side (position closer to the occupant). It is also possible to display

Although the vehicle-mounted display device 1C of this example displays a virtual image of a speedometer or the like, the vehicle-mounted display device 1C of this embodiment is, for example, an electronic rearview mirror that electronically provides the same function as a rearview mirror. It is also possible to apply the present invention to a display unit in a device or a display unit in a navigation device.

Although the embodiment of the present invention has been described in detail above, this is merely an example, and the present invention can be implemented in forms with various modifications without departing from the scope of the invention.

1, 1B head-up display device (in-vehicle display device)
1C in-vehicle display device 5 eyes 10 image display unit 12 virtual image forming optical system 15, 15B optical plate 16 reflection mirror 18 display screen 22 display light 43 display (image display unit)
50 transmission panel (optical plate)
i virtual image k object

Claims (5)

An in-vehicle display device that is mounted in a vehicle and displays information useful for driving the vehicle in front of an occupant,
an image display unit that forms a display image serving as a virtual image and emits display light according to the display image;
a virtual image forming optical system that guides the display light to the eyes of the occupant and allows the occupant to visually recognize a virtual image of the display image;
an optical plate provided on the optical path of the display light and/or between the occupant's eye and the virtual image, and comprising a power adjustment area whose power changes outward in the direction perpendicular to the optical axis;
An in-vehicle display device comprising: The virtual image forming optical system is
a reflecting mirror that reflects the display light emitted from the image display unit;
a display screen having transparency, the display screen further reflecting the display light reflected by the reflecting mirror toward the occupant;
with
2. The in-vehicle display device according to claim 1, wherein the optical plate is provided between the reflecting mirror and the image display section. The virtual image forming optical system is
a reflecting mirror that reflects the display light emitted from the image display unit;
a display screen having transparency, the display screen further reflecting the display light reflected by the reflecting mirror toward the occupant;
with
3. The in-vehicle display device according to claim 1, wherein the optical plate is provided on the virtual image side of the display screen. 4. The in-vehicle display device according to claim 3, wherein the display screen is a windshield of the vehicle or a combiner separate from the windshield. The virtual image forming optical system includes the optical plate provided between the image display unit and the occupant's eyes,
2. The optical plate is provided with the power adjustment region in which a positive power is set in each region through which the line of sight of the passenger passes, and the power changes toward the outer side in the direction perpendicular to the optical axis. 2. The in-vehicle display device according to 1.

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