JP2021103276A - Image display device - Google Patents

Abstract

To provide an image display device capable of displaying three-dimensional images in space and at the same time overlapping them with a background.SOLUTION: An image display device (100) includes: a first image projection part (S1) for radiating a first image; a second image projection part (S2) for radiating a second image; an image-forming optical part (10) for forming a first image at a first distance and forming a second image at a second distance; and a control part (40) for controlling the first image projection part (S1) and the second image projection part (S2). The control part (40) has a luminance balance control part (43) for controlling luminance of the first image and luminance of the second image, and the luminance balance control part (43) changes the luminance of the first image and the luminance of the second image with time.SELECTED DRAWING: Figure 2

Description

The present invention relates to an image display device, and more particularly to an image display device that superimposes and forms an image of a plurality of images in the depth direction of space.

Conventionally, as a device for displaying various information in a vehicle, an instrument panel that lights and displays an icon has been used. Further, as the amount of information to be displayed increases, it is also proposed to embed an image display device in the instrument panel or to configure the entire instrument panel with the image display device.

However, since the instrument panel is located below the windshield of the vehicle, it is not preferable for the driver to visually recognize the information displayed on the instrument panel because it is necessary to move the line of sight downward during driving. Therefore, a head-up display (hereinafter referred to as HUD: Head Up Display) that projects an image on the windshield so that the driver can read the information when he / she visually recognizes the front of the vehicle has also been proposed (for example, Patent Document 1). See). In such a HUD, an optical device for projecting an image onto a wide range of the windshield is required, and it is desired to reduce the size and weight of the optical device.

On the other hand, as an image display device that projects light using a small optical device, a glasses-shaped head-mounted HUD is known (see, for example, Patent Document 2). In the head-mounted HUD, the light emitted from the light source is directly applied to the viewer's eyes, and the image is projected on the viewer's retina.

In addition, DFD that displays two two-dimensional images using two liquid crystal display devices and changes the brightness of both to recognize the image as if it exists in the space at the intermediate position by utilizing the stereoscopic illusion phenomenon. (Deptth Forced 3D) displays have also been proposed (see, eg, Patent Document 3).

Japanese Unexamined Patent Publication No. 2018-118669 Special Table 2018-528446 Japanese Unexamined Patent Publication No. 2009-237310

However, in the conventional head-mounted HUD, although the background and the image can be displayed in an overlapping manner, the displayable image is a two-dimensional image having no depth. Even with the conventional head-mounted HUD, it is possible to display a stereoscopic image by stereoscopic vision by giving binocular parallax to the image to be visually recognized by the left and right eyes, but in principle, two images can be displayed in the visual field of both eyes. It was difficult to superimpose them accurately.

Further, in the stereoscopic illusion on the DFD display, since it is necessary to arrange the two image display devices in the depth direction, it is difficult to use the devices for the head mount type HUD due to the large size of the devices. It is also difficult to superimpose and display the background image and the three-dimensional image.

Therefore, the present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide an image display device capable of superimposing a three-dimensional image on a background while displaying a three-dimensional image in space.

In order to solve the above problems, the image display device of the present invention has a first image projection unit that irradiates the first image, a second image projection unit that irradiates the second image, and a first distance between the first image. The control unit includes an imaging optical unit that forms an image on the image and forms the second image at a second distance, and a control unit that controls the first image projection unit and the second image projection unit. It has a brightness balance control unit that controls the brightness of the first image and the second image, and the brightness balance control unit changes the brightness of the first image and the brightness of the second image over time. It is a feature.

In such an image display device of the present invention, the imaging optical unit is used to form a first image at a first distance, a second image is formed at a second distance, and a brightness balance control unit is used to form a first image. By changing the brightness of the second image over time, it is possible to superimpose the image on the background while displaying the three-dimensional image in space using the DFD stereoscopic illusion.

Further, in one aspect of the present invention, it has a driving unit that changes the imaging position of the first image and / or the second image.

Further, in one aspect of the present invention, the driving unit changes the first distance and / or the second distance.

Further, in one aspect of the present invention, the driving unit translates the first image and / or the second image at the second distance.

Further, in one aspect of the present invention, a beam splitter that reflects a part of the light emitted by the first image projection unit in the first direction and transmits the remaining light in the second direction, and advances in the first direction. The beam splitter includes a first retroreflective unit that retroreflects the generated light to the beam splitter and a second retroreflective unit that retroreflects the light traveling in the second direction to the beam splitter. The light reflected by the retroreflective unit is transmitted in the third direction, the light reflected by the second retroreflective unit is reflected in the third direction, and the light traveling in the third direction is imaged in space. Equipped with a dichroic mirror to make it.

Further, in one aspect of the present invention, the beam splitter reflects a part of the light emitted by the second image projection unit in the first direction and transmits the remaining light in the second direction.

INDUSTRIAL APPLICABILITY The present invention can provide an image display device capable of superimposing a three-dimensional image on a background while displaying a three-dimensional image in space.

It is a schematic diagram which shows the structure of the image display device 100 which concerns on 1st Embodiment. It is a block diagram which shows typically the structure of the image display device 100 which concerns on 1st Embodiment. It is a schematic diagram which shows the time-dependent brightness change of the 1st image A1 and the 2nd image A2 and the stereoscopic display by the DFD stereoscopic illusion in 1st Embodiment. It is a schematic diagram which shows the movement of the 1st image A1 and the 2nd image A2 in 2nd Embodiment. It is a schematic diagram which shows the time-changing stereoscopic display using the DFD stereoscopic illusion, FIG. 5A shows the display at time t = 0, and FIG. 5B shows the display at time t = Δt. There is.

(First Embodiment)
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The same or equivalent components, members, and processes shown in the drawings shall be designated by the same reference numerals, and redundant description will be omitted as appropriate. FIG. 1 is a schematic view showing a configuration of an image display device 100 according to the present embodiment. As shown in FIG. 1, the image display device 100 includes beam splitters BS1 and BS2, retroreflective units RR1 and RR2, a dichroic mirror DM, a first image projection unit S1, a second image projection unit S2, and brightness adjustment. The parts RND1 and RND2 are provided.

In the image display device 100 shown in FIG. 1, the viewer visually recognizes the first image A1 and the second image A2 projected from the first image projection unit S1 and the second image projection unit S2 at different distances in the depth direction. .. In FIG. 1, the direction in which the first image A1 and the second image A2 are lined up is the depth direction, the vertical direction orthogonal to the depth direction is the vertical direction, and the direction orthogonal to the depth direction is the horizontal direction.

The beam splitter BS1 is a member that transmits a part of the incident light and reflects a part of the incident light, and a partial reflector having a film for adjusting the reflectance on the surface can be used. The beam splitter BS1 is arranged so as to have an angle of 45 degrees with respect to the vertical direction and the depth direction. Further, the light is arranged so as to be inclined by 45 degrees with respect to the optical axis of the light emitted from the first image projection unit S1 and the second image projection unit S2.

The retroreflective portions RR1 and RR2 are optical members that reflect the incident light in the incident direction while maintaining the light-collecting property, and use a structure or a prism in which minute glass beads are spread on the surface side of the reflective film. A retroreflective part of the structure can be used. The retroreflective unit RR1 is arranged below the beam splitter BS2, and its main surface is in the horizontal direction. The retroreflective unit RR2 is arranged in the depth direction alongside the beam splitters BS1 and BS2, and the main surface is in the vertical direction.

The beam splitter BS2 is a member that transmits a part of the incident light and reflects a part of the incident light, and a partial reflector having a film for adjusting the reflectance on the surface can be used. The beam splitter BS2 is arranged so as to be inclined at an angle of 45 degrees with respect to the vertical direction and the depth direction. Further, the light is arranged so as to be inclined by 45 degrees with respect to the optical axis of the light emitted from the first image projection unit S1 and the second image projection unit S2. Further, the beam splitter BS2 and the beam splitter BS1 are inclined in opposite directions, and are arranged so as to intersect each other at an angle of 90 degrees.

Here, any balance can be selected between the light transmittance and the reflectance of the beam splitters BS1 and BS2. For example, the transmittance is 50% and the reflectance is 50%. Further, an example in which the tilt angles of the beam splitters BS1 and BS2 are orthogonal to 45 degrees is shown, but from the relationship between the light irradiation direction from the first image projection unit S1 and the second image projection unit S2 and the image formation position of the image. Appropriate angles can be used.

The dichroic mirror DM is an optical member that reflects light of a specific wavelength and transmits light of other wavelengths. The dichroic mirror DM is arranged above the retroreflective portion RR1 and the beam splitter BS2, and is arranged so as to be inclined at an angle of 45 degrees in the depth direction. In the example shown in FIG. 1, as the dichroic mirror DM, a dichroic mirror DM that reflects the wavelength of the light emitted from the first image projection unit S1 and the second image projection unit S2 and transmits other visible light is used. As will be described later, since the first image A1 and the second image A2 are imaged in space by the light reflected by the dichroic mirror DM, the dichroic mirror DM constitutes the imaging optical unit in the present invention. ..

Further, although omitted in FIG. 1, an imaging lens may be arranged between the beam splitter BS2 and the dichroic mirror DM as a part of the imaging optical system. The imaging lens is an optical member for forming an image of light transmitted through the beam splitter BS2 at a predetermined position in space, and a plurality of lens groups may be used.

The first image projection unit S1 and the second image projection unit S2 are devices that irradiate light that constitutes an image, respectively, and project an image at a predetermined distance from the eyes of the viewer. The first image projection unit S1 is arranged below the beam splitter BS1 and irradiates light in the direction perpendicular to the other surface of the beam splitter BS1 (the surface facing the beam splitter BS2). The second image projection unit S2 is arranged in the depth direction along with the beam splitter BS1 and BS2 and the retroreflection unit RR2, and is in the depth direction with respect to one surface of the beam splitter BS1 (the surface opposite to the beam splitter BS2). Is radiated with light.

The configuration of the first image projection unit S1 and the second image projection unit S2 is not limited, and a liquid crystal display device equipped with a backlight, a self-luminous organic EL display device, a projector device using a light source and a modulation element, or the like is used. Can be done. The images projected by the first image projection unit S1 and the second image projection unit S2 may be still images or moving images, and the projected images may be the same or different. Further, each of the first image projection unit S1 and the second image projection unit S2 may include an optical member such as a lens.

The brightness adjusting units RND1 and RND2 adjust the amount of light emitted from the first image projection unit S1 and the second image projection unit S2, respectively, and the brightness of the first image A1 and the second image A2 formed in the air. It is an optical element that controls. The specific configuration of the brightness adjusting units RND1 and RND2 is not limited, but for example, a circular variable ND filter, a polarizing plate, or the like can be used. Further, the brightness may be adjusted by controlling the amount of light emitted by each of the first image projection unit S1 and the second image projection unit S2.

As shown in FIG. 1, the light emitted from the first image projection unit S1 reaches the beam splitter BS2 after being reflected by the beam splitter BS1. Further, the light emitted from the second image projection unit S2 passes through the beam splitter BS1 and then reaches the beam splitter BS2.

A part of the light reaching the beam splitter BS2 is reflected and travels in the retroreflective portion RR1 direction, is rereflected by the retroreflective portion RR1, and reincidents on the beam splitter BS2. The light re-entering the beam splitter BS2 passes through the beam splitter BS2, is reflected by the dichroic mirror DM, and is imaged as the first image A1 and the second image A2. The light formed as the first image A1 and the second image A2 passes through the head-mounted display HMD and reaches the viewer's eyes. Therefore, the viewer visually recognizes the first image A1 and the second image A2 in the air in the depth direction.

The rest of the light that has reached the beam splitter BS2 is transmitted and travels in the retroreflective section RR2 direction, is rereflected by the retroreflective section RR2, and reincidents on the beam splitter BS2. The light re-entering the beam splitter BS2 is partially reflected by the beam splitter BS2, reflected by the dichroic mirror DM, and imaged as the first image A1 and the second image A2.

As shown in FIG. 1, by using the retroreflective unit RR1 and the retroreflective unit RR2, the light retroreflected by the retroreflective unit RR2 is also reflected by the beam splitter BS2 and reaches the dichroic mirror DM, and the first It is imaged as an image A1 and a second image A2. Therefore, since the light transmitted through the beam splitter BS2 and the reflected light are used for imaging the first image A1 and the second image A2, the decrease in the amount of light is suppressed.

At this time, the light retroreflected by the retroreflective unit RR1 and the light retroreflected by the retroreflective unit RR2 are images of the same content branched by the beam splitter BS2, and reach the dichroic mirror DM by superimposing them on each other. There is a need to. Therefore, when the optical characteristics of the retroreflective unit RR1 and the retroreflective unit RR2 are the same, the distance from the retroreflective unit RR1 and the retroreflective unit RR2 to the beam splitter BS2 is equalized, or the distance is made an integral multiple of the wavelength. It is preferable to do so.

As described above, in the viewer, the light forming the first image A1 and the second image A2 is incident on the visual field range of the same viewer and is located at different positions in the depth direction at the first distance and the second distance. , The first image A1 and the second image A2 can be visually recognized. At the same time, the viewer can visually recognize the background that reaches the eyes through the dichroic mirror DM. Therefore, the viewer visually recognizes an aerial image in which the first image A1 and the second image A2 are superimposed on the background.

Further, the brightness adjusting units RND1 and RND2 control the light reaching the beam splitter BS1 from the first image projection unit S1 and the second image projection unit S2, so that the first image A1 and the second image formed in space are formed. The brightness of the image A2 is controlled.

FIG. 2 is a block diagram schematically showing the configuration of the image display device 100 according to the present embodiment. The image display device 100 includes an imaging optical unit 10, a projection unit 20, a driving unit 30, and a control unit 40.

The imaging optical unit 10 includes a first imaging optical unit 11 and a second imaging optical unit 12, and is an element that forms an image of the first image A1 and the second image A2 at a predetermined distance in the air, each of which is a plurality of elements. It is configured by combining the optical members of. In the example shown in FIG. 1, the first imaging optical unit 11 includes an optical member included in the first image projection unit S1, beam splitters BS1 and BS2, a first retroreflective unit RR1, a second retroreflective unit RR2, and a dichroic filter. It is composed of a mirror DM. Similarly, the second imaging optical unit 12 is composed of an optical member included in the second image projection unit S2, beam splitters BS1 and BS2, a first retroreflective unit RR1, a second retroreflective unit RR2, and a dichroic mirror DM. There is.

The projection unit 20 includes a first image projection unit S1 and a second image projection unit S2, and is an element that irradiates light for forming a plurality of images. The light emitted from the first image projection unit S1 and the second image projection unit S2 passes through the first imaging optical unit 11 and the second imaging optical unit 12, respectively, to the first image at the first distance and the first image at the second distance. A1 and the second image A2 are imaged.

The drive unit 30 includes a first drive unit 31 and a second drive unit 32, which are the first image projection unit S1, the first imaging optical unit 11, the second image projection unit S2, and the second imaging optical unit 12, respectively. It is an element that mechanically changes the position and angle of. The specific configuration of the drive unit 30 is not limited, and known motors and actuators can be used. Further, the first drive is a configuration in which a large screen display device is used as the first image projection unit S1 and the second image projection unit S2, and the light irradiation position is changed by changing the area for displaying an image in the large screen. The unit 31 and the second drive unit 32 may be used.

The control unit 40 includes an information processing unit 41, an image processing unit 42, a brightness balance control unit 43, and a drive control unit 44, and controls the operation of each unit included in the image display device 100. The information processing unit 41 is a part that processes various information according to a predetermined procedure, and is a computer including a central processing unit (CPU: Central Processing Unit), a memory, an external storage device, and various interfaces. Further, the information processing unit 41 controls the operations of the image processing unit 42, the luminance balance control unit 43, and the drive control unit 44, and synchronizes the processing of the image signal and the control signal.

The image processing unit 42 processes each image information projected by the projection unit 20 and sends an image signal to the first image projection unit S1 and the second image projection unit S2 to irradiate the light constituting each image. It is the part to make.

The brightness balance control unit 43 controls the amount of light emitted from the first image projection unit S1 and the second image projection unit S2 by driving and controlling the brightness adjustment units RND1 and RND2, and forms an image in space. This is a portion for adjusting the brightness of the first image A1 and the second image A2.

The drive control unit 44 is a part that controls the operation of the drive unit 30, and transmits a control signal instructing the operation of the first drive unit 31 and the second drive unit 32. The control signal from the drive control unit 44 includes information on the position and angle of any one of the first image projection unit S1, the first imaging optical unit 11, the second image projection unit S2, and the second imaging optical unit 12. Is included.

FIG. 3 is a schematic view showing a change in brightness of the first image A1 and the second image A2 with time and a stereoscopic display by a DFD stereoscopic illusion in the present embodiment. In FIG. 3, the luminance of the first image A1 and the second image A2 is expressed as a shade of gray scale, the dark color represents the high brightness and the light color represents the low brightness.

As shown in FIG. 3A, when the first image A1 is imaged with high brightness and the second image A2 is imaged with low brightness, the viewer can see the imaging position of the first image A1 having high brightness due to the stereoscopic illusion. Recognize the image on the side closer to. As an example, when the relative brightness of the first image A1 is 100 and the relative brightness of the second image A2 is 0, the position of the two-dimensional image recognized by the viewer in the stereoscopic illusion is the connection of the first image A1. It becomes the image position.

As shown in FIG. 3B, when the brightness of the first image A1 and the second image A2 are about the same, the positions of the two-dimensional images recognized by the viewer in the stereoscopic illusion are the first image A1 and the first image A1. 2 It is an intermediate position of the image A2.

As shown in FIG. 3C, when the first image A1 is imaged with low brightness and the second image A2 is imaged with high brightness, the viewer can see the imaging position of the second image A2 having high brightness due to the stereoscopic illusion. Recognize the image on the side closer to. As an example, when the relative brightness of the first image A1 is 0 and the relative brightness of the second image A2 is 100, the position of the two-dimensional image recognized by the viewer in the stereoscopic illusion is the connection of the second image A2. It becomes the image position.

In FIG. 3, an example of 100: 0, 50:50, 0: 100 is shown as the brightness balance of the first image A1 and the second image A2, but even if the brightness balance is other, the viewer has a stereoscopic illusion. Recognizes a two-dimensional image at an intermediate position between the first image A1 and the second image A2. Here, assuming that the brightness balance between the first image A1 and the second image A2 is a: b, the distance l between the first image A1 and the second image A2 is divided by the ratio of a: b. The dimensional image is recognized.

In the image display device 100 of the present embodiment, the brightness balance control unit 43 changes the brightness balance a: b of the first image A1 and the second image A2 over time, so that the viewer can image the first image A1. A plurality of two-dimensional images are visually recognized by stereoscopic illusion even at an intermediate point from the position to the image formation position of the second image A2. Therefore, the viewer recognizes the three-dimensional illusion image DFD as shown in FIG. 3 (d).

The luminance balance control by the luminance balance control unit 43 is repeated with 100: 0 to 0: 100 as one frame. As the number of steps of the luminance balance a: b in one frame increases, the stereoscopic illusion at the intermediate position in the illusion image DFD increases, and more stereoscopic expression becomes possible. Further, if the time required for one frame is too long, it is recognized that the two-dimensional image is only moving in the depth direction. Therefore, the time required for one frame is preferably 200 milliseconds or less. In addition, if the viewing angle difference between the two frames is 7 minutes or less, a three-dimensional illusion is possible, which is preferable.

As described above, in the image display device 100 of the present embodiment, the luminance balance control unit 43 changes the luminance of the first image A1 and the second image A2 with time, and corresponds to the luminance balance a: b in one frame. By recognizing the image by the three-dimensional illusion at the position, the three-dimensional illusion image DFD can be displayed in space and superimposed on the background.

(Second Embodiment)
Next, the second embodiment of the present invention will be described with reference to FIGS. 4 and 5. The description of the contents overlapping with the first embodiment will be omitted. In the present embodiment, in addition to displaying the stereoscopic illusion image DFD using the brightness balance control unit 43, the imaging position of the first image A1 or the second image A2 imaged in space is changed. , Change the shape of the stereoscopic image to be imaged.

FIG. 4 is a schematic view showing the movement of the first image A1 and the second image A2 in the present embodiment. The drive control unit 44 controls the first drive unit 31 and the second drive unit 32 to change the imaging positions of the first image A1 and the second image A2 between the time t = 0 and the time t = Δt. Let me. In the example shown in FIG. 4, the first image A1 is translated in the horizontal direction and the second image A2 is changed in the second distance in the depth direction, but both can be moved in the horizontal direction and the depth direction. it can.

5A and 5B are schematic views showing a time-varying stereoscopic display using the DFD stereoscopic illusion, FIG. 5A shows the display at time t = 0, and FIG. 5B shows time t = Δt. Shows the display. Here, an example in which the first image A1 is simply translated in the horizontal direction is shown. At time t = 0, the first image A1 is imaged at the first distance, the second image A2 is imaged at the second distance, and the brightness balance a: b is changed over time by the brightness balance control unit 43. By doing so, an illusion image DFD having a rectangular parallelepiped shape as shown in FIG. 5A is displayed in one frame.

After that, at time t = Δt, the drive control unit 44 changes the imaging position of the first image A1, and the brightness balance control unit 43 changes the brightness balances a: b over time, whereby FIG. 5 in one frame. An illusion image DFD with a distorted rectangular parallelepiped shape as shown in (b) is displayed. At this time, the viewer recognizes that the shape of the illusion image DFD has changed between t = 0 and t = Δt. Therefore, if the imaging positions of the first image A1 and the second image A2 are changed each time the time Δt elapses, the viewer will view the animation by the three-dimensional illusion image DFD.

Here, Δt needs to be longer than the time of one frame required to depict the three-dimensional illusion image DFD, but it is desirable that Δt is set to 200 milliseconds or less in order to recognize it as a moving image. More preferably, by setting Δt in the range of 30 to 60 milliseconds, smooth moving images can be recognized.

Also in the image display device 100 of the present embodiment, the luminance balance control unit 43 changes the luminance of the first image A1 and the second image A2 with time, and a stereoscopic illusion is performed at a position corresponding to the luminance balance a: b in one frame. By recognizing the image according to the above, it is possible to superimpose the image on the background while displaying the three-dimensional illusion image DFD in the space. Further, the stereoscopic illusion image DFD can be displayed as a moving image by changing the imaging position of the first image A1 and / or the second image A2 by the drive control unit 44.

The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and the embodiments obtained by appropriately combining the technical means disclosed in the different embodiments. Is also included in the technical scope of the present invention.

100 ... Image display device 10 ... Imaging optical unit 11 ... First imaging optical unit 12 ... Second imaging optical unit 20 ... Projection unit 30 ... Drive unit 31 ... First drive unit 32 ... Second drive unit 40 ... Control Unit 41 ... Information processing unit 42 ... Image processing unit 43 ... Brightness balance control unit 44 ... Drive control unit BS1, BS2 ... Beam splitter RR1, RR2 ... Retroreflective unit RND1, RND2 ... Brightness adjustment unit DM ... Dycroic mirror A1 ... First Image A2 ... Second image S1 ... First image projection unit S2 ... Second image projection unit

Claims (6)

The first image projection unit that irradiates the first image and
A second image projection unit that irradiates the second image,
An imaging optical unit that forms an image of the first image at a first distance and an image of the second image at a second distance.
A control unit that controls the first image projection unit and the second image projection unit is provided.
The control unit includes a brightness balance control unit that controls the brightness of the first image and the second image.
The luminance balance control unit is an image display device characterized in that the luminance of the first image and the luminance of the second image are changed over time. The image display device according to claim 1.
An image display device comprising a driving unit that changes the imaging position of the first image and / or the second image. The image display device according to claim 2.
The drive unit is an image display device characterized by changing the first distance and / or the second distance. The image display device according to claim 2 or 3.
The drive unit is an image display device that translates the first image and / or the second image at the second distance. The image display device according to any one of claims 1 to 4.
A beam splitter that reflects a part of the light emitted by the first image projection unit in the first direction and transmits the remaining light in the second direction.
A first retroreflective unit that retroreflects light traveling in the first direction to the beam splitter,
A second retroreflective unit that retroreflects the light traveling in the second direction to the beam splitter is provided.
The beam splitter transmits the light reflected by the first retroreflective unit in the third direction, and reflects the light reflected by the second retroreflective unit in the third direction.
An image display device including a dichroic mirror that forms an image of light traveling in the third direction in space. The image display device according to claim 5.
The beam splitter is an image display device characterized in that a part of the light emitted by the second image projection unit is reflected in the first direction and the remaining light is transmitted in the second direction.

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