WO2015076144A1

WO2015076144A1 - Display device

Info

Publication number: WO2015076144A1
Application number: PCT/JP2014/079783
Authority: WO
Inventors: 小幡　雅人; 高橋　祐一
Original assignee: 日本精機株式会社
Priority date: 2013-11-25
Filing date: 2014-11-11
Publication date: 2015-05-28
Also published as: JP2015102695A; JP6268978B2

Abstract

Provided is a display device that can display a virtual image in equivalent positions to users with different heights of viewpoint. A display device (1) emits display light (L) showing an image toward a transparent member and displays a virtual image of the image by means of the display light (L) reflected by the transparent member. The display device (1) is provided with a display instrument (10) that emits the display light (L) showing the image, and an optical element (31) that is an optical element (31) to which the display light (L) emitted by the display instrument (10) is incident and which transmits and emits the incident display light (L), and that emits the display light (L) toward the transparent member by varying the angle of an optical axis for the emitted light with respect to the optical axis of the incident light. The optical element (31) can undergo parallel movement, and the light path for the display light (L) emitted by the optical element (31) and reflected by the transparent member can be changed in correspondence with the parallel movement of the optical element (31).

Description

Display device

The present invention relates to a display device, and more particularly to a display device that displays a virtual image by projecting display light from a display element onto a transparent member.

For example, a display device disclosed in Patent Document 1 is known as this type of display device. In the display device according to Patent Document 1, the display light from the display element is reflected by the reflecting portion and projected onto the transparent member. The reflecting portion is rotatable and the height of the display position of the virtual image is adjusted according to the rotation of the reflecting portion.

JP 2005-181640 A

In the configuration of the display device according to Patent Document 1, there is no problem in the case of a user with an average viewpoint height assumed in advance, but for a user with a higher viewpoint, the display position of the virtual image is shifted downward. On the contrary, the display position of the virtual image is shifted upward for a user with a low viewpoint. When such a thing occurs, for example, when it is desired to display information superimposed on the front landscape using AR (Augmented Reality), the display position of the virtual image shifts from the desired position.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a display device capable of displaying a virtual image at an equivalent position to users having different viewpoint heights.

In order to achieve the above object, a display device according to the present invention includes:
A display device that emits display light representing an image toward a transparent member and displays a virtual image of the image by display light reflected by the transparent member,
Display means for emitting display light representing the image;
An optical element on which the display light emitted from the display means is incident and transmits the incident display light to be emitted, wherein the transparent member is changed by changing an angle of the optical axis of the emitted light with respect to the optical axis of the incident light. An optical element that emits display light toward
The optical element can be translated, and an optical path of display light emitted from the optical element and reflected by the transparent member changes according to the translation of the optical element.
It is characterized by that.

According to the present invention, it is possible to display a virtual image at an equivalent position to users with different viewpoint heights.

It is a figure for demonstrating the display mode of the display apparatus which concerns on one Embodiment of this invention. It is a schematic block diagram of the display apparatus which concerns on one Embodiment of this invention. (A) is a figure for demonstrating the usefulness of the display apparatus which concerns on one Embodiment of this invention, (b) is a figure for demonstrating the problem which had arisen with the display apparatus which concerns on a prior art example. is there. It is a figure for demonstrating the relationship between the incident light with respect to a display element, and emitted light. (A) And (b) is a figure which shows the modification of a display element.

An embodiment of the present invention will be described with reference to FIGS.

The display device 1 according to the present embodiment is configured as a head-up display device disposed on the dashboard of the vehicle 2, and emits display light L representing a predetermined image toward the windshield 3 (windshield). The virtual image V of the image is displayed in front of the windshield 3 by the display light L reflected by the windshield 3. In this way, the display device 1 configured as a head-up display device causes the user 4 (mainly the driver of the vehicle 2) to visually recognize the virtual image V over the scenery in front of the vehicle 2. The image visually recognized as the virtual image V notifies information (engine speed, navigation information, etc.) regarding the vehicle 2, for example.

As shown in FIG. 2, the display device 1 includes a display 10, a reflection unit 20, an optical path adjustment unit 30, and a housing 40. Hereinafter, in order to facilitate understanding of the configuration of the display device 1, the vertical direction as viewed from the user 4 viewing the virtual image V is appropriately described as the vertical direction of each member.

The display 10 is a liquid crystal display, for example, and includes a liquid crystal display panel 11, a light emitting diode 12, a printed wiring board 13, a diffusion plate 14, and a case body 15.

The liquid crystal display panel 11 is obtained, for example, by attaching a polarizing film to a TFT (Thin Film Transistor) type liquid crystal cell. The light emitting diode 12 functions as a backlight that illuminates the liquid crystal display panel 11 from the back side. The light emitting diode 12 is mounted on a printed wiring board 13 located on the back side of the liquid crystal display panel 11. The diffusing plate 14 is a translucent plate material having a diffusing surface composed of fine irregularities, and is located between the light emitting diode 12 and the liquid crystal display panel 11. The diffusion plate 14 diffuses the light emitted from the light emitting diode 12 to reach the liquid crystal display panel 11. The case body 15 holds the liquid crystal display panel 11, the printed wiring board 13, and the diffusion plate 14.

The liquid crystal display panel 11 and the light emitting diode 12 are driven by a control unit (not shown). This control unit acquires information about the vehicle 2 from an external device (not shown) such as an ECU (Electronic Control Unit) of the vehicle 2 and displays an image on the liquid crystal display panel 11 according to the acquired information. Specifically, the control unit switches each pixel of the liquid crystal display panel 11 to a transmission / non-transmission state according to an image to be displayed. And the liquid crystal display panel 11 displays an image by transmitting and illuminating the light emitting diode 12. Light (display light L) representing an image displayed on the liquid crystal display panel 11 travels toward the reflection unit 20.

The reflecting portion 20 is made of a reflecting mirror in which a reflecting surface is formed by evaporating a metal such as aluminum on a resin such as polycarbonate. The reflecting surface is a concave surface, so that the virtual image V becomes larger than the image displayed on the liquid crystal display panel 11. The reflection unit 20 is located on the rear side of the vehicle 2 with respect to the display 10 and reflects the optical path of the display light L from the display 10 so as to be folded back. The display light L reflected by the reflection surface of the reflection unit 20 travels to the optical path adjustment unit 30.

The optical path adjustment unit 30 includes an optical element 31, a holding member 32, and a stepping motor 33, and is positioned between the reflection unit 20 and a translucent cover 41 described later.

The optical element 31 is composed of, for example, a holographic optical element (HOE), and emits the incident light while changing the direction at a predetermined angle. Since the holographic optical element can change the traveling direction of light at a relatively deep angle while being a thin sheet, the optical path adjustment unit 30 can be configured compactly.

The holding member 32 is made of a resin such as ABS (Acrylonitrile Butadiene Styrene), and includes a stationary portion 32a fixed to the housing 40 and immovable relative to the housing, and a movable portion 32b movable relative to the immobile portion 32a. Have. The movable part 32b moves in the vertical direction with respect to the non-moving part 32a by the rotational power of the stepping motor 33. That is, the movable part 32b is movable in the vertical direction with respect to the housing 40. The movable portion 32b has a window frame shape when viewed from above, and holds the optical element 31 so as to surround the outer edge of the optical element 31. Thereby, the optical element 31 can be translated in the vertical direction with respect to the housing 40.

Stepping motor 33 rotates the rotating shaft under the control of the above-described control unit (not shown). A gear 33 a is attached to the rotating shaft, and the movable portion 32 b of the holding member 32 moves up and down by the power of the stepping motor 33 through a gear mechanism (not shown) that is fastened to the gear 33 a.

The optical element 31 can be moved in the vertical direction by the optical path adjustment unit 30 configured as described above. For example, in the display device 1, the stepping motor 33 rotates the rotation shaft in response to a user operation from an operation unit (push button, switch, etc.) (not shown). The vertical position can be adjusted.

The housing 40 fixes and stores each of the display 10, the reflection unit 20, and the optical path adjustment unit 30 at a position satisfying the above-described functions. In the upper part of the housing 40, there is provided an emission port 40 a composed of an opening through which the display light L reflected by the reflection unit 20 and transmitted through the optical element 31 is passed. Further, the casing 40 is provided with a translucent cover 41 that covers the emission port 40a. The translucent cover 41 is made of a translucent resin such as acrylic, and transmits the display light L that passes through the optical element 31 and moves upward. The display light L emitted from the display device 10 is transmitted through the translucent cover 41, emitted from the emission port 40 a to the outside of the display device 1, and travels toward the windshield 3. The translucent cover 41 is formed in a curved shape so as not to reflect the reached external light as much as possible in the direction of the user 4.

Here, a mechanism for displaying the virtual image V by the display device 1 will be briefly described.
The display light L emitted from the display device 10 is reflected by the reflection unit 20 and travels toward the optical element 31. The emission direction of the display light L transmitted through the optical element 31 is changed with respect to the incident direction (upper left direction in FIG. 2) by the function of the optical element 31 (the emission direction is the upper right direction in FIG. 2). The display light L that has passed through the optical element 31 is emitted from the emission port 40 a and travels toward the windshield 3. The virtual image V is displayed in front of the windshield 3 by the display light L reflected by the windshield 3. In this way, the display device 1 causes the user 4 to visually recognize the virtual image V of the image.

Hereafter, how the display position of the virtual image V changes according to the parallel movement of the optical element 31 will be described with reference to FIG. 2, FIG. 3 (a), and FIG. In the following description, the position of the optical element 31 in the case of the optical path of the display light L represented by the solid line in FIGS. 2 and 3A will be described as the reference position.

When the movable portion 32b of the holding member 32 is translated downward by the operation of the user 4 from the operation portion and the optical element 31 is positioned below the reference position, as shown in FIGS. 2 and 3A, The optical path between the reflection unit 20 and the optical element 31 is shortened. Then, the display light L1 when the optical element 31 is positioned below the reference position (hereinafter, referred to as “display light L1 at the lower position”) has an optical path whose optical path is shorter than the display light L at the reference position. Therefore, as shown in FIG. 3A, the light is reflected above the windshield 3 rather than the display light L at the reference position. Thereby, the display light L1 at the lower position reflected by the windshield 3 reaches the user 4 through the optical path above the display light L at the reference position. Thus, for the user 4 whose viewpoint is higher than the average viewpoint position assumed in advance, the virtual image V is visually recognized at the display position equivalent to the user of the average viewpoint.
On the other hand, when the movable portion 32b of the holding member 32 is translated upward by the operation of the user 4 from the operation portion, and the optical element 31 is positioned above the reference position, as shown in FIGS. In addition, the optical path between the reflection unit 20 and the optical element 31 becomes longer. Then, the display light L2 when the optical element 31 is positioned above the reference position (hereinafter referred to as “display light L2 at the upper position”) has an optical path with a longer distance than the display light L at the reference position. Therefore, as shown in FIG. 3A, the reflected light is reflected below the windshield 3 rather than the display light L at the reference position. Thereby, the display light L2 at the upper position reflected by the windshield 3 reaches the user 4 through the optical path below the display light L at the reference position. Thus, for the user 4 whose viewpoint is lower than the average viewpoint position assumed in advance, the virtual image V is visually recognized at the display position equivalent to the user of the average viewpoint.

As described above, in the display device 1, the optical axis position of the display light after passing through the optical element 31 changes according to the vertical position of the optical element 31. The amount of change in the optical axis position is proportional to the amount of parallel movement of the optical element 31, but the angle of the optical axis of the outgoing light (the display light emitted from the optical element 31) with respect to the optical axis of the display light incident on the optical element 31 is determined. The larger the value is, the smaller the amount of parallel movement of the optical element 31 is. That is, as the amount of change in the optical axis before and after passing through the optical element 31 is increased, the space occupied by the optical path adjustment unit 30 in the housing 40 can be reduced.

From the viewpoint of suppressing an increase in the occupied space of the optical path adjustment unit 30 as much as possible, the ratio of the movement amount of the optical element 31 to the change amount of the optical axis before and after passing through the optical element 31 is approximately twice or less. It is preferable that Here, as shown in FIG. 4, the optical axis of the display light L incident on the optical element 31 (the optical axis of the incident light) AX1 and the optical axis of the display light L emitted from the optical element 31 (the optical axis of the emitted light). ) The angle formed by AX2 is θ, the parallel movement change amount (movement distance) of the optical element 31 is Δh, and the change amount of the optical axis before and after passing through the optical element 31 (the change amount of the optical axis corresponding to Δh). Let Δd. Then, the relationship of tan θ = Δd / Δh is established. When the ratio of the amount of movement of the optical element 31 to the amount of change in the optical axis before and after passing through the optical element 31 is doubled, tan θ = 1/2, and θ at this time is about 26.6. Degree. Thereby, in order to make the ratio of the movement amount of the optical element 31 to the change amount of the optical axis before and after passing through the optical element 31 approximately twice or less, at least θ is preferably 25 degrees or more. I understand that. Therefore, from the viewpoint of suppressing the occupied space of the optical path adjusting unit 30 as much as possible, it is preferable to select the optical element 31 in which θ is 25 degrees or more before and after the passage of the display light.

Next, with reference to FIGS. 3A and 3B, the usefulness of the display device 1 according to the present embodiment will be described in comparison with the conventional example. The embodiment shown in FIG. FIG. 3B shows a display device 1P according to a conventional example. In addition, in order to facilitate understanding of the following description, in the display device 1P according to the conventional example, the same reference numerals as those of the respective portions of the display device 1 are used for components having the same functions as those of the display device 1 according to the present embodiment. Was attached.

The display device 1P according to the conventional example enables the display of the virtual image V according to the viewpoint height of the user 4 by rotating the reflection unit 20 like the display device according to Patent Document 1 described above. It is. In the display device 1P according to the conventional example, when the reflection unit 20 is rotated clockwise, the display light (display light L1) is reflected on the windshield 3 at a position above the display light L at the reference position. Thereby, it is possible to adjust so that the virtual image V can be seen well even for the user 4 whose viewpoint is higher than the average viewpoint position assumed in advance. On the contrary, when the reflecting portion 20 is rotated counterclockwise, the display light (display light L2) is reflected on the windshield 3 at a position below the display light L at the reference position. Thereby, it is possible to adjust the virtual image V so that it can be seen well even for the user 4 whose viewpoint is lower than the average viewpoint position assumed in advance.
However, when the reflecting portion 20 is rotated and moved in this way, the display light reflected by the windshield 3 is extended forward in any case where the reflecting portion 20 is rotated clockwise or counterclockwise. The optical path has a position (corresponding point O2 shown in FIG. 3B) corresponding to a position (reference point O1 shown in FIG. 3B) where the display light from the display 10 is incident on the reflecting surface of the reflecting portion 20. (In addition, the projection of the reflection part 20 is shown with the code | symbol 20v in FIG.3 (b) along with corresponding point O2).
That is, the extension optical path forward of the display light reflected by the windshield 3 is bound to the corresponding point O2, and the display light L1 that matches the user 4 with a high viewpoint passes through the corresponding point O2 and becomes a virtual image. Since the display position is shifted downward (see the virtual image V1 in FIG. 3B), the display light L2 that matches the user 4 with a low viewpoint is also visually recognized as a virtual image that has passed through the corresponding point O2. The display position is shifted upward (see the virtual image V2 in FIG. 3B). This problem becomes more prominent as the display position of the set virtual image V becomes farther from the windshield 3.

On the other hand, in the display device 1 according to the present embodiment, the optical path of the display light is changed by translating the optical element 31 in the vertical direction as described above.
As described above, when the optical element 31 is moved in parallel, the optical path obtained by extending the display light reflected by the windshield 3 forwards the optical path of the display light incident on the windshield 3 in theory. A virtual image V is formed at a position (corresponding point O2 shown in FIG. 3 (a)) corresponding to the position (reference point O1 shown in FIG. 3 (a)) (note that the projection of the optical element 31 is combined with the corresponding point O2). (Indicated by reference numeral 31v in FIG. 3A).
In this case, unlike the case where the reflection unit 20 is rotated, the corresponding point O2 is not located between the windshield 3 and the virtual image V, and the corresponding point O2 itself is the imaging position of the virtual image V. That is, the virtual image V is formed at the same position by the optical path of the display light L1 matched to the user 4 with a high viewpoint and the optical path of the display light L2 matched to the user 4 with a low viewpoint. Therefore, according to the display device 1 according to the present embodiment, it is possible to display the virtual image V at the same position on the user 4 having a different viewpoint height. According to the display device 1, even if the height of the viewpoint of the user 4 is different, the virtual image is visually recognized by the user 4 at the position desired by the device provider simply by adjusting the position of the optical element 31 by parallel movement. Therefore, it is particularly useful when it is desired to display information superimposed on the front scenery using AR (Augmented Reality).
These effects can be realized by the following configuration.

The display device 1 is a display device 1 that emits display light L representing an image toward a windshield 3 (an example of a transparent member) and displays a virtual image V of the image by the display light L reflected by the windshield 3. The display device 10 (an example of display means) that emits display light L representing an image, and the optical element 31 that the display light L emitted from the display device 10 enters and transmits and emits the incident display light L. And an optical element 31 that emits the display light L toward the windshield 3 by changing the angle of the optical axis AX2 of the outgoing light with respect to the optical axis AX1 of the incident light. In accordance with the parallel movement of the optical element 31, the optical path of the display light L emitted from the optical element 31 and reflected by the windshield 3 changes.

The display device 1 further includes a reflection unit 20 that reflects the display light L emitted from the display 10 toward the optical element 31, and the optical element 31 is emitted from the display 10 and reflected by the reflection unit 20. The displayed light L is incident.

In addition, the display device 1 is mounted on the vehicle 2, and the display 10 emits display light L toward the reflection unit 20 located on the rear side of the vehicle 2 with respect to the display 10 and is reflected by the reflection unit 20. The light L passes through the optical element 31 and is emitted toward the windshield 3.

In addition, this invention is not limited by the above embodiment and drawing. Changes (including deletion of constituent elements) can be added to the embodiments and the drawings as appropriate without departing from the scope of the present invention. An example of modification is shown below.

(Modification)
The example in which the optical element 31 is a holographic optical element has been described above, but is not limited thereto. The optical element is an optical element 31a made up of a wedge-shaped prism as shown in FIG. 5A, or an optical element 31b made up of a Fresnel lens cut into parallel lines as shown in FIG. 5B. May be.

In the above, the example in which the optical element 31 is translated in the vertical direction of the display device 1 has been described. However, the display device 1 may be configured such that the optical element 31 is translated in an oblique direction.

Further, a configuration in which the display light L from the display device 10 is directly incident on the optical element 31 without passing through the reflection unit 20 is possible, and after the display light L is transmitted through the optical element 31, the reflection unit made of a magnifying glass. A configuration is also possible in which the display light L is reflected at 20 and the virtual image V is enlarged.

In the above description, the vehicle 2 is an example of a vehicle on which the display device 1 is mounted. However, the present invention is not limited to this. The display device 1 can also be installed on other vehicles (ships, aircraft, etc.). Furthermore, it is not restricted to what is installed in a vehicle.

In the above, the example in which the display device 1 is disposed in the dashboard of the vehicle 2 has been shown. However, the display device 1 is, for example, a stationary type (retrofitted type) installed on the dashboard of the vehicle. May be. Further, the transparent member that projects the display light L is not limited to the windshield 3, and may be a transparent member (so-called combiner) dedicated to the display device 1.

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

The present invention is applied to a display device, and more specifically, is suitable for a display device that displays a virtual image by projecting display light from a display element onto a transparent member.

DESCRIPTION OF SYMBOLS 1 ... Display apparatus 1P ... Display apparatus which concerns on a prior art example 2 ... Vehicle 3 ... Windshield 4 ... User 10 ... Display device 20 ... Reflection part 30 ... Optical path adjustment part 31 ... Optical element 32 ... Holding member 32a ... Non-moving part 32b ... Movable Part 33 ... Stepping motor 40 ... Housing 40a ... Outlet 41 ... Translucent cover L ... Display light V ... Virtual image

Claims

A display device that emits display light representing an image toward a transparent member and displays a virtual image of the image by display light reflected by the transparent member,
Display means for emitting display light representing the image;
An optical element on which the display light emitted from the display means is incident and transmits the incident display light to be emitted, wherein the transparent member is changed by changing an angle of the optical axis of the emitted light with respect to the optical axis of the incident light. An optical element that emits display light toward
The optical element can be translated, and an optical path of display light emitted from the optical element and reflected by the transparent member changes according to the translation of the optical element.
A display device characterized by that.
A reflection unit that reflects the display light emitted from the display unit toward the optical element;
Display light that is emitted from the display means and reflected by the reflecting portion is incident on the optical element.
The display device according to claim 1.
The display device is mounted on a vehicle, and the transparent member is a windshield of the vehicle,
The display means emits display light toward the reflecting portion located on the rear side of the vehicle with respect to the display means,
The display light reflected by the reflecting part is transmitted through the optical element and emitted toward the windshield.
The display device according to claim 2.