JP7372618B2 - In-vehicle display device - Google Patents

Description

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

A head-up display device as a vehicle-mounted display device includes an image display unit that forms a display image that is the source of a virtual image and emits display light according to the display image, and a combiner that serves as a display screen that projects 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 approximately 2 meters away from the occupant). This virtual image is displayed superimposed on the foreground of the vehicle seen through the windshield (windshield), but the position where the virtual image is displayed is usually based on objects in the foreground that the occupants are observing (such as the road spreading out in front of them, etc.). (e.g. cars running on the road). For this reason, when the occupant changes the visual object from a virtual image to an object in the foreground, or from an object in the foreground to a virtual image, it is necessary to use the accommodation power of the eyes to adjust the focus. It will happen.

Repeated accommodation causes accommodative eye strain. Furthermore, if the object in the foreground and the virtual image are far apart and the parallax is large, recognition is likely to deteriorate, and in particular, elderly people with reduced accommodation may have difficulty seeing the object. For this reason, it is desirable that the virtual image displayed in front of the occupant be displayed as close to the object in the foreground as possible. However, in order to achieve this, it is necessary to increase the optical path length between the image display section and the combiner in order to display the virtual image further away than the current position, which increases the size and complexity of the device. I invite you.

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

JP 2017-226292 Publication

The present invention solves the above-mentioned problems, and aims to provide an in-vehicle display device that can reduce the burden on a passenger to adjust the focus when viewing virtual images and objects in the foreground. do.

The present invention is an in-vehicle display device that is mounted on a vehicle and displays information useful for driving the vehicle in front of a passenger,
an image display unit that forms a display image that is a source of 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 occupant's eyes and allows the occupant to visually recognize the virtual image of the display image;
an optical plate provided on the optical path of the display light and/or between the occupant's eyes and the virtual image, and including a power adjustment region whose power changes as it goes outward in a direction perpendicular to the optical axis;
It is characterized by having the following.

According to the present invention, when the virtual image is visually recognized, the virtual image is in focus due to the effect of extending the depth of field by the optical plate provided on the optical path of the display light and/or between the passenger's eyes and the virtual image. The depth of field that is considered to be in focus and/or the depth of field that is considered to be in focus when an object in the foreground of the vehicle is seen is extended, making it easier to see the virtual image and objects in the foreground. When doing so, the burden on the occupant to adjust the focus can be reduced.

In the present invention, the virtual image forming optical system further includes a reflective mirror that reflects the display light emitted from the image display section and a transparent display screen, the display screen that reflects the display light reflected by the reflective mirror. A display screen that reflects toward the passenger side,
The optical plate may 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 longitudinal direction of the vehicle due to the effect of extending the depth of field by the optical plate.

In the present invention, the virtual image forming optical system further includes a reflection mirror that reflects the display light emitted from the image display section and a transparent display screen, the display screen that reflects the display light reflected by the reflection mirror. It further comprises a display screen that reflects toward the passenger side,
The optical plate may be provided on the virtual image side of the display screen.
In this way, due to the depth of field extension effect of the optical plate, the depth of field when viewing the foreground of the vehicle can be extended in the longitudinal direction of the vehicle, for example, even when focusing on a virtual image. This has the effect of making it easier to recognize distant scenery (the foreground of the vehicle).

Here, in the present invention, the display screen can be a 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 section and the passenger,
The optical plate may be configured to include a power adjustment region in which a positive power is set in each region through which the passenger's line of sight passes, and the power changes as the power changes toward the outside in a direction perpendicular to the optical axis.
In this way, due to the depth of field extension effect of the optical plate, the display image displayed on the image display section can be visually recognized as a virtual image displayed further forward of the vehicle than the actual display image. 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 a 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 of the same optical plate along the direction orthogonal to the optical axis. Figure 3 (A) is a diagram schematically showing a change in power that is different from Figure 2 (B), and Figure 3 (B) is a diagram that schematically shows a change in power that is different from Figure 2 (B) and Figure 3 (A). FIG. FIG. 4 is a diagram showing a schematic configuration of a head-up display device as an in-vehicle display device according to a 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 of the same optical plate along the direction orthogonal to the optical axis. FIG. 6 is a diagram showing a schematic configuration of an in-vehicle display device according to a third embodiment. 7(A) is a diagram showing the transmission panel of FIG. 6, and FIG. 7(B) is a diagram schematically showing the change in power of the transmission panel along the direction perpendicular to the optical axis.

<First embodiment>
Next, a head-up display device as an in-vehicle display device according to a first embodiment will be described based on the drawings. In FIG. 1, reference numeral 1 denotes a head-up display device that displays a virtual image i on an extension of a line connecting the eyes 5 of a passenger seated 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 a virtual image, a virtual image forming optical system 12 that allows an occupant to visually recognize the virtual image of the displayed image, and displays a virtual image within a certain width range. and an optical plate 15 for controlling the image. 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 section 10 includes, for example, a small liquid crystal panel equipped with a backlight as a light source. The image display unit 10 forms images showing values of various instruments such as a speedometer and fuel gauge, map images in a navigation system, etc. as display images based on information received from a control unit (not shown), and displays these images. A display image is displayed on the display surface 10a of the image display section 10. Then, by transmitting light from the backlight through the liquid crystal panel, display light 22 having information of a display image is emitted from the display surface 10a.
Note that as the image display section 10, it is possible to appropriately employ a projector or the like that displays an image by scanning a laser beam in a two-dimensional direction.

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

The projection lens 14 is arranged in front of the image display section 10 to face the display surface 10a of the image display section 10, and is arranged so that the optical axis of the projection lens 14 coincides with the reference optical axis L. The display light 22 emitted from the section 10 is projected onto a reflecting mirror 16. The projection lens 14 may be composed of a single lens, or may be composed of a combination of a plurality of lenses.

The reflecting mirror 16 is a mirror that reflects the display light 22 sent via the projection lens 14 toward the display screen 18, and is arranged with the concave surface 16a, which is a reflecting surface, facing the projection lens 14 side. has been done. The display light 22 emitted from the image display unit 10 is magnified by the projection lens 14 and the reflection mirror 16, and is transmitted to the display screen 18 located above the instrument panel 3 through the opening 4 formed in the instrument panel 3. be projected.

The display screen 18 is a transmissive concave mirror or a plane mirror made of a half mirror such as a combiner. It is installed upright on the instrument panel 3 and reflects the display light 22 from the reflection mirror 16 toward the rear side of the vehicle. Note that the display screen can also be configured by the windshield 2 of the vehicle.

The display light 22 reflected by the display screen 18 is guided to the eyes 5 and the surrounding area of the passenger seated in the driver's seat. 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 eyes 5 and the display screen 18. The position of the virtual image i that can be virtually recognized without passing through the optical plate 15 is the position indicated by i ₀ in FIG. 1 . Moreover, according to the display screen 18 which is a half mirror, external light passing through the display screen 18 is also guided to the occupant's eyes 5 and the surrounding area thereof. Therefore, the occupant can also observe the foreground of the vehicle through the display screen 18, and as a result, the virtual image at the position i ₀ can be observed superimposed on the foreground of the vehicle.

In this embodiment, an optical plate 15 is disposed between the reflection mirror 16 and the projection lens 14. The optical plate 15 is a lens having a width in focal length, and is arranged so that the optical axis of the optical plate 15 coincides with the reference optical axis L.

In this example, as shown in FIG. 2A, the optical plate 15 is a lens whose front surface (reflection mirror side) 27 and rear surface (image display section side) are both convex, and the front surface 27 and rear surface 28 are optical lenses. It has a rotationally symmetric shape around an optical axis passing through the center O (base point O ₁ on the rear surface 28 and base point O ₂ on the front surface 27). As shown in FIG. 2(B), the optical plate 15 has a power of S ₀ diopter at the optical center (S ₀ is a positive value in this example, but may be zero or a negative value depending on the case). The aspherical component added to the front surface 27 and/or the rear surface 28 creates a power adjustment region 30 (see FIG. B) is formed.

Here, as the aspherical component added to the lens surface, an aspherical component represented by Σ{A _n r ⁿ } can be exemplified. However, r: distance from the optical axis, A _n : aspheric coefficient, n: positive integer. Σ{ } is a symbol indicating the sum within { }. ^For example, the ^aspherical component may be represented ^by _A4r4 + _A6r6 + _A8r8 + ^{A10r10 ,} or _{A3r3 .} The aspherical coefficient A _n for specifying the aspherical component can be appropriately determined by a simulation using ray tracing or the like so as to obtain desired optical characteristics (change in power).
Note that the optical plate 15 does not have to 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 have a concave shape.

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

Therefore, according to the head-up display device 1 of the present embodiment, as shown in FIG. The burden of adjusting the focus when the occupant shifts his/her line of sight to the object k included in the foreground can be reduced.

Note that, as shown in FIG. 2(B), 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, but the mode of power change is limited to this. It can be changed as appropriate without any restrictions. For example, as shown in FIG. 3A, the power of the lens central region 31 within a 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 also possible to form a region 32 outside the power adjustment region 30 in which the power is maintained at a predetermined value (there is no change in power). Further, in this example, the optical plate 15 is provided separately from the projection lens 14, but the optical plate 15 is configured integrally with the projection lens 14, and the projection lens 14 is provided with a power adjustment area. It is also possible to realize the frequency distribution shown in FIG.

In addition, in the power adjustment area 30 of the optical plate 15, the power is changed to the negative side as it goes to the outside in the direction r orthogonal to the optical axis (toward the peripheral edge of the optical plate), so that the virtual image i is moved closer to the front side (a position closer to the passenger). It is also possible to display the

<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 source of a 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 depth of field. and an optical plate 15B that is extended. Among these components, the components common to those of the head-up display device 1 described above are indicated using the same reference numerals, and the explanation thereof will be omitted.

In the head-up display device 1 according to the first embodiment, an optical plate is disposed between the reflection 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, the optical plate 15B is a lens having a concave front surface 27 and a rear surface 28, as shown in _FIG . 27 has a rotationally symmetrical shape around the optical axis passing through the base point O ₂ ). As shown in FIG. 5(B), 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 depending on the case). The aspherical component added to the front surface 27 and/or the rear surface 28 creates a power adjustment region 30 (see FIG. B) is formed. Note that the optical plate 15B may have one surface convex and the other surface concave.

In the head-up display device 1B equipped with the optical plate 15B configured in this way, the depth of field G when viewing the foreground of the vehicle is adjusted to the front side of the vehicle (occupants) due to the depth of field extension effect of the optical plate 15B. For example, even when focused on virtual image i, it is possible to easily recognize distant scenery (object k included in the foreground of the vehicle). Therefore, when viewing the virtual image i and the object k in the foreground, the burden on the occupant to adjust the focus can be reduced.

In this example, the optical plate 15B is provided separately from the display screen 18, but it is also possible to configure the optical plate 15B integrally with the display screen 18. Further, in this example, an optical plate 15B is provided in place of the above-mentioned optical plate 15, but it is also possible to provide a head-up display device in which both optical plates 15 and 15B are provided.

In addition, in the power adjustment area 30 of the optical plate 15B, when the power is changed to the positive side toward the outside in the direction r orthogonal to the optical axis (towards the peripheral edge of the optical plate), the depth of field changes to the rear side of the vehicle (occupants The virtual image in the foreground can be seen more easily even when viewing distant scenery (the 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 section (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 facing toward the rear of the vehicle. The display 43 displays an image of a speedometer or the like on a display surface 43a based on the information received by the control unit. By transmitting light from the backlight through the liquid crystal panel, display light 22 having information of a display image (image of a speedometer, etc.) is emitted from the display surface 43a.

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

Here, the transparent panel 50 is a lens having a plus power set in each region through which the passenger's line of sight passes, and having a width in focal length. As shown in FIG. 7A, the transmissive panel 50 is a lens with a front surface (occupant side) 51 and a rear surface (image display side) both having a convex shape, and the front surface 51 and/or the rear surface 52 have an optical center O( The rear surface 52 has a rotationally symmetrical shape around the optical axis passing through the base point O ₁ and the front surface 51 through the base point O ₂ . As shown in FIG. 7B, the transmission panel 50 has a power of S ₂ diopters at the optical center (S ₂ is a positive value), and has an aspherical component added to the front surface 51 and/or the rear surface 52. A power adjustment region 30 is formed in which the power changes toward the plus side as it goes toward the outside (peripheral side) in the direction r orthogonal to the optical axis.

A normal lens has one focal length, but the transmissive panel 50 of this example has a focal length ranging from a certain value to a certain value. In other words, when light parallel to the optical axis is incident on a normal lens, the light is focused on one point on the optical axis, but when light parallel to the optical axis is incident on the transmission panel 50, the light is focused from a certain point on the optical axis. Light is focused in a certain range up to a certain point. Therefore, on the transmission panel 50, the displayed image as the object is observed and formed as a virtual image within a certain width range.

According to the in-vehicle display device 1C equipped with the transparent panel 50 configured in this way, as shown in FIG. ), a virtual image i indicating a speedometer, etc. is displayed within a certain range.
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 etc. and the position of the object included in the foreground of the vehicle becomes small, so that, for example, the virtual image i can be visually recognized. When the occupant who has been watching the vehicle shifts his/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 of the transmission panel 50, by changing the power to the negative side toward the outside (toward the peripheral edge of the optical plate) in the direction r orthogonal to the optical axis, the virtual image i is moved closer to the front (position closer to the occupant). It is also possible to display the

Although the in-vehicle display device 1C of this example displays a speedometer or the like as a virtual image, the in-vehicle 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 section in a device or a display section in a navigation device.

Although the embodiments of the present invention have been described in detail above, this is merely an example, and the present invention can be implemented with various modifications without departing from the spirit thereof.

1,1B Head-up display device (in-vehicle display device)
1C Vehicle-mounted display device 5 Eyes 10 Image display section 12 Virtual image forming optical system 15, 15B Optical plate 16 Reflection mirror 18 Display screen 22 Display light 43 Display (image display section)
50 Transparent panel (optical plate)
i virtual image k object

Claims (5)

An in-vehicle display device that is mounted on a vehicle and displays information useful for driving the vehicle in front of a passenger,
an image display unit that forms a display image that is a source of 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 occupant's eyes and allows the occupant to visually recognize the virtual image of the display image;
It is provided on the optical path of the display light, has a power with a positive value at the optical center and a minimum absolute value (including the case of zero), and extends outward in the direction perpendicular to the optical axis all around the optical axis. an optical plate including a power adjustment area in which the power changes to a positive side as the power increases;
Equipped with
The virtual image forming optical system is
a reflecting mirror that reflects the display light emitted from the image display section;
a display screen that is transparent and further reflects the display light reflected by the reflection mirror toward a passenger;
Equipped with
The vehicle-mounted display device is characterized in that the optical plate is provided between the reflective mirror and the image display section . An in-vehicle display device that is mounted on a vehicle and displays information useful for driving the vehicle in front of a passenger,
an image display unit that forms a display image that is a source of 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 occupant's eyes and allows the occupant to visually recognize the virtual image of the display image;
an optical plate provided between the occupant's eye and the virtual image, and comprising a power adjustment region whose power changes as it goes outward in a direction perpendicular to the optical axis;
Equipped with
The virtual image forming optical system is
a reflecting mirror that reflects the display light emitted from the image display section;
a display screen that is transparent and further reflects the display light reflected by the reflection mirror toward a passenger;
Equipped with
The vehicle- mounted display device is characterized in that the optical plate is provided on the virtual image side of the display screen. 3. The vehicle-mounted display device according to claim 2 , wherein the display screen is a windshield of the vehicle or a combiner separate from the windshield. An in-vehicle display device that is mounted on a vehicle and displays information useful for driving the vehicle in front of a passenger,
an image display unit that forms a display image that is a source of 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 occupant's eyes and allows the occupant to visually recognize the virtual image of the display image;
an optical plate provided between the occupant's eye and the virtual image, and comprising a power adjustment region whose power changes as it goes outward in a direction perpendicular to the optical axis;
Equipped with
The virtual image forming optical system includes the optical plate provided between the image display section and the occupant's eyes,
The optical plate has a positive power set in each area through which the passenger's line of sight passes, and has a power with a positive value and a minimum absolute value at the optical center, and the optical plate has a positive power value at the optical center and a minimum absolute value. An in-vehicle display device comprising the power adjustment area in which the power changes toward the plus side as the power goes outward in the orthogonal direction. 5. The vehicle-mounted display device according to claim 1, wherein the optical plate has a front surface and a rear surface that are rotationally symmetrical about an optical axis passing through an optical center.

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