WO2025100550A1 - 表示装置、結像装置、表示システムおよび車両 - Google Patents

表示装置、結像装置、表示システムおよび車両 Download PDF

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Publication number
WO2025100550A1
WO2025100550A1 PCT/JP2024/040045 JP2024040045W WO2025100550A1 WO 2025100550 A1 WO2025100550 A1 WO 2025100550A1 JP 2024040045 W JP2024040045 W JP 2024040045W WO 2025100550 A1 WO2025100550 A1 WO 2025100550A1
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WO
WIPO (PCT)
Prior art keywords
retardation plate
semi
display
display device
light
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/JP2024/040045
Other languages
English (en)
French (fr)
Japanese (ja)
Inventor
薫 草深
昭典 佐藤
和正 松田
卓 島田
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Kyocera Corp
Original Assignee
Kyocera Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Kyocera Corp filed Critical Kyocera Corp
Priority to KR1020257031744A priority Critical patent/KR20250151535A/ko
Priority to CN202480004796.XA priority patent/CN120303608A/zh
Priority to JP2024568414A priority patent/JP7725744B1/ja
Priority to EP24883535.7A priority patent/EP4603892A4/en
Priority to CN202580003943.6A priority patent/CN121646726A/zh
Priority to JP2025534708A priority patent/JP7747936B1/ja
Priority to PCT/JP2025/017146 priority patent/WO2025234496A1/ja
Priority to KR1020267002991A priority patent/KR20260023602A/ko
Priority to US19/209,490 priority patent/US20250277982A1/en
Publication of WO2025100550A1 publication Critical patent/WO2025100550A1/ja
Priority to JP2025128981A priority patent/JP2025172065A/ja
Priority to JP2025130909A priority patent/JP2025169300A/ja
Priority to JP2025244897A priority patent/JP7826561B1/ja
Priority to JP2025244900A priority patent/JP2026065646A/ja
Priority to JP2025244896A priority patent/JP7842938B1/ja
Anticipated expiration legal-status Critical
Pending legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/01—Head-up displays
    • G02B27/017—Head mounted
    • G02B27/0172—Head mounted characterised by optical features
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
    • B60K35/00—Instruments specially adapted for vehicles; Arrangement of instruments in or on vehicles
    • B60K35/20—Output arrangements, i.e. from vehicle to user, associated with vehicle functions or specially adapted therefor
    • B60K35/21—Output arrangements, i.e. from vehicle to user, associated with vehicle functions or specially adapted therefor using visual output, e.g. blinking lights or matrix displays
    • B60K35/22—Display screens
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
    • B60K35/00—Instruments specially adapted for vehicles; Arrangement of instruments in or on vehicles
    • B60K35/20—Output arrangements, i.e. from vehicle to user, associated with vehicle functions or specially adapted therefor
    • B60K35/21—Output arrangements, i.e. from vehicle to user, associated with vehicle functions or specially adapted therefor using visual output, e.g. blinking lights or matrix displays
    • B60K35/23—Head-up displays [HUD]
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
    • B60K35/00—Instruments specially adapted for vehicles; Arrangement of instruments in or on vehicles
    • B60K35/40—Instruments specially adapted for improving the visibility thereof to the user, e.g. fogging prevention or anti-reflection arrangements
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
    • B60K35/00—Instruments specially adapted for vehicles; Arrangement of instruments in or on vehicles
    • B60K35/60—Instruments characterised by their location or relative disposition in or on vehicles
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/01—Head-up displays
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/01—Head-up displays
    • G02B27/0101—Head-up displays characterised by optical features
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/02—Viewing or reading apparatus
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/02—Viewing or reading apparatus
    • G02B27/022—Viewing apparatus
    • G02B27/024—Viewing apparatus comprising a light source, e.g. for viewing photographic slides, X-ray transparancies
    • G02B27/026—Viewing apparatus comprising a light source, e.g. for viewing photographic slides, X-ray transparancies and a display device, e.g. CRT, LCD, for adding markings or signs or to enhance the contrast of the viewed object
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/09—Beam shaping, e.g. changing the cross-sectional area, not otherwise provided for
    • G02B27/0938—Using specific optical elements
    • G02B27/0977—Reflective elements
    • G02B27/0983—Reflective elements being curved
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/28—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for polarising
    • G02B27/286—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for polarising for controlling or changing the state of polarisation, e.g. transforming one polarisation state into another
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B30/00—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images
    • G02B30/20—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images by providing first and second parallax images to an observer's left and right eyes
    • G02B30/26—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images by providing first and second parallax images to an observer's left and right eyes of the autostereoscopic type
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B30/00—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images
    • G02B30/20—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images by providing first and second parallax images to an observer's left and right eyes
    • G02B30/26—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images by providing first and second parallax images to an observer's left and right eyes of the autostereoscopic type
    • G02B30/27—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images by providing first and second parallax images to an observer's left and right eyes of the autostereoscopic type involving lenticular arrays
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B30/00—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images
    • G02B30/20—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images by providing first and second parallax images to an observer's left and right eyes
    • G02B30/26—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images by providing first and second parallax images to an observer's left and right eyes of the autostereoscopic type
    • G02B30/30—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images by providing first and second parallax images to an observer's left and right eyes of the autostereoscopic type involving parallax barriers
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/08—Mirrors
    • G02B5/0816—Multilayer mirrors, i.e. having two or more reflecting layers
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G02B5/3083—Birefringent or phase retarding elements
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
    • B60K2360/00—Indexing scheme associated with groups B60K35/00 or B60K37/00 relating to details of instruments or dashboards
    • B60K2360/20—Optical features of instruments
    • B60K2360/23—Optical features of instruments using reflectors
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
    • B60K2360/00—Indexing scheme associated with groups B60K35/00 or B60K37/00 relating to details of instruments or dashboards
    • B60K2360/20—Optical features of instruments
    • B60K2360/29—Holographic features
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
    • B60K35/00—Instruments specially adapted for vehicles; Arrangement of instruments in or on vehicles
    • B60K35/20—Output arrangements, i.e. from vehicle to user, associated with vehicle functions or specially adapted therefor
    • B60K35/21—Output arrangements, i.e. from vehicle to user, associated with vehicle functions or specially adapted therefor using visual output, e.g. blinking lights or matrix displays
    • B60K35/211—Output arrangements, i.e. from vehicle to user, associated with vehicle functions or specially adapted therefor using visual output, e.g. blinking lights or matrix displays producing three-dimensional [3D] effects, e.g. stereoscopic images
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/01—Head-up displays
    • G02B27/0101—Head-up displays characterised by optical features
    • G02B2027/0132—Head-up displays characterised by optical features comprising binocular systems
    • G02B2027/0134—Head-up displays characterised by optical features comprising binocular systems of stereoscopic type
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/01—Head-up displays
    • G02B27/017—Head mounted
    • G02B27/0172—Head mounted characterised by optical features
    • G02B2027/0174—Head mounted characterised by optical features holographic

Definitions

  • This disclosure relates to a display device, an imaging device, a display system, and a vehicle.
  • a display device such as that described in Patent Document 1 is known.
  • the display device of the present disclosure includes a display panel that emits display light; a first retardation plate facing the display panel; a second retardation plate disposed apart from the first retardation plate; a reflective polarizing plate disposed opposite the second retardation plate and transmitting the first polarized light and reflecting the second polarized light; a semi-transmitting mirror disposed between the first retardation plate and the second retardation plate and having a reflecting surface facing the second retardation plate,
  • the first and second retardation plates convert the display light into a first polarized light and a second polarized light.
  • the display device of the present disclosure includes a display panel that emits display light; a first retardation plate that transmits the display light; a second retardation plate disposed apart from the first retardation plate; a first semi-transmitting mirror disposed between the display panel and the first retardation plate and having a first reflecting surface facing the first retardation plate; a second semi-transparent mirror disposed between the first retardation plate and the second retardation plate and having a second reflecting surface facing the first retardation plate; a polarizing plate facing the second retardation plate, The first retardation plate and the second retardation plate divide the display light into a first polarized light that is transmitted through the polarizing plate and a second polarized light that is less transmitted through the polarizing plate than the first polarized light.
  • the display device of the present disclosure includes a display panel that emits display light; a first retardation plate that transmits the display light; a second retardation plate disposed apart from the first retardation plate; a first semi-transmitting mirror disposed between the display panel and the first retardation plate and having a first reflecting surface facing the first retardation plate; a second semi-transparent mirror disposed between the first phase difference plate and the second phase difference plate, the second semi-transparent mirror having a second reflecting surface facing the first phase difference plate and a third reflecting surface facing the second phase difference plate; a third semi-transparent mirror having a fourth reflecting surface facing the second retardation plate.
  • the imaging device disclosed herein includes the display device described above.
  • the display device of the present disclosure includes a display panel; an optical system that projects a display light emitted from the display panel as a virtual image or a real image; a housing that houses the display panel and the optical system, the housing has a window through which light emitted from the optical system passes, The window of the housing is arranged so that the window, the optical system, and the display panel overlap when the window is viewed from the front.
  • the vehicle disclosed herein is equipped with the above-mentioned display device.
  • the display device of the present disclosure includes a display panel that emits display light; a convex lens through which the display light passes, The optical path length from the display panel to the convex lens is shorter than the focal length of the convex lens.
  • the display device of the present disclosure includes a display panel that emits display light; a convex lens through which the display light passes, The optical path length from the display panel to the convex lens is greater than the focal length of the convex lens.
  • a display system includes the above-described display device and A camera;
  • the display panel is capable of communicating with the camera and displays an image captured by the camera.
  • the vehicle disclosed herein is equipped with the above-mentioned display system.
  • FIG. 1 is a diagram illustrating a schematic configuration of a display device according to the present disclosure.
  • 1 is a cross-sectional view illustrating an example of a configuration of a main part of a display device according to an embodiment of the present disclosure.
  • 11 is a cross-sectional view showing another example of a main configuration of a display device according to an embodiment of the present disclosure.
  • FIG. 11 is a cross-sectional view showing an example of a main configuration of a display device according to another embodiment of the present disclosure.
  • 11 is a cross-sectional view showing another example of a main configuration of a display device according to another embodiment of the present disclosure.
  • FIG. 1 is a diagram illustrating a schematic configuration of a display device according to the present disclosure.
  • 1 is a cross-sectional view illustrating an example of a configuration of a main part of a display device according to an embodiment of the present disclosure.
  • 11 is a cross-sectional view showing another example of a main configuration of a display device according to an
  • FIG. 5 is a diagram illustrating the projection of a virtual image in the display device of FIG. 4.
  • 6 is a diagram illustrating the projection of a virtual image in the display device of FIG. 5 .
  • 6 is a diagram for explaining the design of an optical system in the display device of FIG. 5 .
  • 13 is a cross-sectional view showing an example of a configuration of a main part of a display device according to still another embodiment of the present disclosure.
  • FIG. FIG. 1 is a diagram illustrating an example of a configuration of an imaging device according to an embodiment of the present disclosure.
  • FIG. 13 is a diagram illustrating another example of the configuration of an imaging device according to an embodiment of the present disclosure.
  • FIG. 13 is a diagram illustrating another example of the configuration of an imaging device according to an embodiment of the present disclosure.
  • FIG. 13 is a diagram illustrating another example of the configuration of an imaging device according to an embodiment of the present disclosure.
  • FIG. 11 is a top view illustrating another example of the display device.
  • FIG. 11 is a top view illustrating another example of the display device.
  • FIG. 11 is a cross-sectional view illustrating another example of a display device.
  • FIG. 11 is a cross-sectional view illustrating another example of a display device.
  • FIG. 13 is a diagram illustrating an optical system in another example of a display device.
  • FIG. 13 is a diagram illustrating an optical system in another example of a display device.
  • FIG. 13 is a diagram illustrating an optical system in another example of a display device.
  • FIG. 13 is a diagram illustrating an optical system in another example of a display device.
  • FIG. 13 is a diagram illustrating an optical system in another example of a display device.
  • FIG. 13 is a diagram illustrating an optical system in another example of a display device.
  • FIG. 13 is a diagram illustrating an optical system in another example of a display device.
  • FIG. 13 is a diagram illustrating an optical system in another example of a display device.
  • FIG. 13 is a diagram illustrating an optical system in another example of a display device.
  • FIG. 13 is a diagram illustrating an optical system in another example of a display device.
  • 13 is a graph illustrating an optical system in another example of a display device.
  • FIG. 11 is a cross-sectional view illustrating another example of a display device.
  • FIG. 11 is a cross-sectional view illustrating another example of a display device.
  • FIG. FIG. 11 is a cross-sectional view illustrating another example of a display device.
  • FIGS. 1A and 1B are diagrams illustrating how a virtual image appears when a user is positioned in front of the display device.
  • 1A and 1B are diagrams illustrating how a virtual image appears when a user is not positioned in front of the display device.
  • 11A and 11B are diagrams for explaining how a virtual image appears when the display device is adjusted.
  • 11A and 11B are diagrams for explaining how a virtual image appears when the display device is adjusted.
  • 11 is a flowchart illustrating control of the imaging device.
  • FIG. 11 is a cross-sectional view showing another example of a main configuration of a display device according to an embodiment of the present disclosure.
  • FIG. 11 is a cross-sectional view showing another example of a main configuration of a display device according to another embodiment of the present disclosure.
  • FIG. 13 is a cross-sectional view showing another example of a main configuration of a display device according to still another embodiment of the present disclosure.
  • FIG. FIG. 11 is a perspective view showing a cross section of another example of a display device according to an embodiment of the present disclosure.
  • FIG. 11 is a cross-sectional view illustrating another example of a display device according to an embodiment of the present disclosure.
  • FIG. 11 is a perspective view showing a cross section of another example of a display device according to an embodiment of the present disclosure.
  • FIG. 11 is a cross-sectional view illustrating another example of a display device according to an embodiment of the present disclosure.
  • 3 is a diagram showing an optical path of display light in the display device of FIG. 2.
  • FIG. 3 is a cross-sectional view showing another example of the display device of FIG. 2 .
  • 1 is a diagram illustrating an example of a configuration of a display system and a vehicle according to an embodiment of the present disclosure.
  • Patent Document 1 Various small display devices have been proposed for use in digital rearview mirrors placed inside the vehicle cabin, head-mounted displays worn on the user's head, and the like.
  • the display device described in Patent Document 1 is configured to emit display light emitted from a display panel via multiple optical components such as a retardation plate and a reflective polarizing plate.
  • FIG. 1 Some of the drawings used in the following description are schematic.
  • the drawings used in the following description show the main components of the display device and virtual image display device of the present disclosure.
  • the display device and virtual image display device of the present disclosure may include well-known components not shown, such as a holding member for the optical system and a housing.
  • a Cartesian coordinate system XYZ is defined in some of the drawings.
  • the Y-axis direction is also referred to as the height direction.
  • the Z-axis direction is also referred to as the emission direction or depth direction.
  • Figures 1 to 39 are diagrams or graphs for explaining the display device, imaging device, display system, and vehicle of the present disclosure.
  • Figures 2 to 5 9, 15, 16, 20 to 22, 24, and 30 to 32, for ease of illustration, the optical path of light incident on a light-reflective optical element and the optical path of light reflected by the optical element are shown shifted in the height direction (Y-axis direction).
  • a display device 1 includes a display panel 2 and an optical system 3.
  • the display device 1 allows a portion of the display light emitted from the display panel 2 to enter the eye of the user 22, and allows the user 22 to view the display on the display panel 2 at a position different from the position of the display panel 2 from the display light emitted from the display panel 2.
  • the display device 1 allows the user 22 to view the display on the display panel 2 as a virtual image V.
  • the virtual image V may be formed on a side farther from the display device 1 as viewed from the user 22.
  • the virtual image V may be an upright virtual image obtained by enlarging the display image displayed on the display panel 2.
  • the virtual image V may be formed inside the housing or outside the housing.
  • the virtual image V may be formed on a side farther from the display panel 2 as viewed from the user 22, or on a side closer to the display panel 2.
  • the housing has a window 37 (see FIGS. 33 to 36) that transmits the display light emitted from the optical system 3
  • the virtual image V may be formed on the side farther from the window 37 (light-transmitting plate 38) as viewed by the user 22, or may be formed on the side closer to the window.
  • the display device 1 has a touch panel 41 (see FIGS. 35 and 36)
  • the virtual image V may be formed on the side farther from the touch panel 41 as viewed by the user 22, or may be formed on the side closer to the touch panel 41.
  • the display device 1 may be configured to allow a portion of the display light emitted from the display panel 2 to be incident on the eye of the user 22, and to be viewed by the user 22 as a real image.
  • the real image may be formed on a side closer to the user 22 than the display device 1. If the display device 1 has a housing 36 (see Figures 33 to 36) that houses the display panel 2 and the optical system 3, the real image may be formed inside the housing 36 or outside the housing 36. The real image may be formed on a side farther from the display panel 2 or closer to the display panel 2, as viewed by the user 22.
  • the real image may be formed on a side farther from the window 37 (light-transmitting plate 38) or closer to the window 37 (light-transmitting plate 38), as viewed by the user 22.
  • the display device 1 has a touch panel 41 (see Figures 35 and 36)
  • the real image may be formed on the farther side of the touch panel 41 from the user 22's perspective, or may be formed on the closer side of the touch panel 41.
  • the display panel 2 has a display surface 2a, and displays a display image on the display surface 2a.
  • the display panel 2 emits display light for the display image from the display surface 2a.
  • the display panel 2 may be configured to emit linearly polarized display light. Below, a case will be described in which the display panel 2 emits S-wave polarized display light, but the present invention is not limited to this.
  • the display panel 2 may be a liquid crystal panel.
  • the liquid crystal panel may have a known liquid crystal panel configuration.
  • the known liquid crystal panel may be, for example, an IPS (In-Plane Switching) type, an FFS (Fringe Field Switching) type, a VA (Vertical Alignment) type, an ECB (Electrically Controlled Birefringence) type, or other liquid crystal panel.
  • the display device 1 may include an illuminator 4 that illuminates the display panel 2 in a planar manner.
  • the illuminator 4 is also referred to as a backlight.
  • the illuminator 4 may be an edge-light type backlight or a direct type backlight.
  • An edge-light type backlight has one or more light sources arranged on the outer periphery of the display panel 2, and guides the light emitted from the light source to the entire back surface of the display panel 2 by a light guide plate to distribute the light evenly.
  • a direct type backlight has multiple light sources arranged on the back surface of the display panel 2, and illuminates the display panel 2 with light emitted from the multiple light sources.
  • the light source of the illuminator 4 may be a cold cathode fluorescent lamp, a halogen lamp, a xenon lamp, or the like, or may be a light-emitting diode (LED), an organic light-emitting diode (OLED), a semiconductor laser (LD), or the like. If the light source of the irradiator 4 is an LD with excellent monochromaticity, the design of the optical system 3, in particular the design of optical components whose optical characteristics are wavelength dependent, becomes easier.
  • the display panel 2 is not limited to a liquid crystal panel (transmissive display panel).
  • the display panel 2 may be a self-emitting display panel including self-emitting elements such as light-emitting diodes (Light Emitting Diodes; LEDs), organic light-emitting diodes (Organic Light Emitting Diodes; OLEDs), and semiconductor lasers (Laser Diodes; LDs).
  • the optical system 3 projects the display light emitted from the display panel 2 into the visual field of the user 22 as a virtual image V.
  • the optical system 3 may include a first retardation plate 5, a semi-transparent mirror 6, a second retardation plate 7, and a reflective polarizer 8.
  • the first retardation plate 5, the semi-transparent mirror 6, the second retardation plate 7, and the reflective polarizer 8 are arranged in this order in the emission direction of the display light from the display panel 2 (positive direction in the Z-axis direction).
  • the first retardation plate 5 is positioned opposite the display surface 2a of the display panel 2.
  • the first retardation plate 5 is positioned away from the display surface 2a in the emission direction of the display light from the display panel 2.
  • the second retardation plate 7 is positioned away from the first retardation plate 5 in the emission direction of the display light from the display panel 2.
  • the first retardation plate 5 and the second retardation plate 7 are quarter-wave plates.
  • the first retardation plate 5 and the second retardation plate 7 impart a phase difference of quarter wavelength to the polarization plane of the incident light (polarization plane in the electric field vibration direction). This makes it possible to reflect a portion of the display light emitted from the display panel 2 by the reflective polarizer 8 and make it incident on the semi-transparent mirror 6.
  • the first retardation plate 5 and the second retardation plate 7 only need to provide the necessary phase difference to the light transmitted through the first retardation plate 5 and the second retardation plate 7 so that the light transmitted through the first retardation plate 5 and the second retardation plate 7 is reflected by the reflective polarizer 8.
  • the first retardation plate 5 and the second retardation plate 7 may be other wave plates or a combination thereof instead of quarter wave plates, as long as the second polarized light is obtained. Note that in this disclosure, an example will be described in which the first retardation plate 5 and the second retardation plate 7 are quarter wave plates.
  • the second phase difference plate 7 only needs to give the necessary phase difference to the light that has been transmitted through the second phase difference plate 7 so that the light that has been reflected by the reflective polarizer 8 and transmitted through the second phase difference plate 7 is transmitted through the reflective polarizer 8 when it reaches the reflective polarizer 8 again.
  • the second phase difference plate 7 need not be a quarter wave plate but may be another wave plate as long as the first polarized light is obtained.
  • the first retardation film 5 may be integrated with the display panel 2 as shown in FIG. 30.
  • integrated may mean that the two members are arranged so as to be in contact with each other, or that the two members are joined to each other by an optically clear adhesive such as OCA (Optically Clear Adhesive).
  • the semi-transmitting mirror 6 is located between the first retardation plate 5 and the second retardation plate 7.
  • the semi-transmitting mirror 6 may transmit a portion of the incident light (e.g., approximately 50%) and reflect the remaining portion (e.g., approximately 50%).
  • the semi-transmitting mirror 6 reflects a portion of the display light reflected by the reflective polarizing plate 8 and causes the light to enter the eye of the user 22. This allows the user 22 to view the virtual image V.
  • the semi-transmitting mirror 6 may be a concave mirror having a concave reflecting surface 6a facing the second retardation plate 7.
  • the semi-transmitting mirror 6 may include a spherical shape, an aspherical shape, or a free-form shape on at least a portion of the reflecting surface 6a.
  • the semi-transmitting mirror 6 is configured to include, for example, a substrate and a semi-transmitting reflective layer located on the surface of the substrate.
  • the substrate may have a transmittance of 100% or close to 100% for light in the visible light band.
  • the substrate may be configured to include, for example, a resin material, a glass material, etc.
  • the resin material may be, for example, an acrylic resin, a polycarbonate resin, etc.
  • the semi-transmitting reflective layer may be a metal thin film.
  • the metal thin film may be configured to include a metal material such as aluminum or chromium.
  • the semi-transmitting reflective layer is not limited to a metal thin film and may be, for example, a dielectric multilayer film, etc.
  • the semi-transmitting mirror 6 may be configured to reflect light by a semi-transmitting reflective layer.
  • the semi-transmitting reflective layer may be formed on the surface of the substrate facing the second retardation plate 7.
  • the reflective polarizer 8 is positioned opposite the surface of the second retardation plate 7 opposite the surface facing the semi-transmitting mirror 6. In other words, the reflective polarizer 8 is positioned after the second retardation plate 7 in the emission direction of the display light from the display panel 2.
  • the reflective polarizer 8 may transmit a part of the incident light and reflect the rest.
  • the reflective polarizer 8 is configured to reflect polarized light having a polarization axis perpendicular to the polarization axis of the display light (P-wave polarized light, also called the second polarization) and transmit polarized light having a polarization axis parallel to the polarization axis of the display light (S-wave polarized light, also called the first polarization). This makes it possible for the user 22 to view the virtual image V.
  • the reflective polarizer 8 may be integrated with the second retardation plate 7 as shown in FIG. 30.
  • the reflective polarizer 8 may be, for example, a wire grid polarizer including a substrate and a plurality of thin metal wires (also called metal nanowire grid) located on the surface of the substrate.
  • the substrate may have a transmittance of 100% or close to 100% for light in the visible light band.
  • the substrate may be made of, for example, a resin material, a glass material, or the like.
  • the thin metal wires may be made of a metal material such as aluminum, chromium, titanium oxide, or the like.
  • the thin metal wires may be arranged along one direction.
  • the reflective polarizer 8 can transmit light components that vibrate in a direction perpendicular to the grid, and can reflect light components that vibrate in a direction parallel to the grid.
  • the display device 1 includes a controller 43.
  • the controller 43 is connected to each component of the display device 1 and controls each component.
  • the controller 43 may control the irradiator 4.
  • the controller 43 may control the display image displayed on the display panel 2 and the irradiator 4.
  • the controller 43 may control the irradiator 4 based on the display image displayed on the display panel 2.
  • the controller 43 may be configured to include one or more processors.
  • the processor may include a general-purpose processor configured to load a specific program and execute a specific function, and a dedicated processor specialized for a specific process.
  • the processor may include a PLD (Programmable Logic Device).
  • the controller 43 may be either a SoC (System-on-a-Chip) in which one or more processors work together, or a SiP (System In a Package).
  • the controller 43 includes a memory unit, and may store various information, or programs for operating each component of the display device 1, in the memory unit.
  • the memory unit may be configured, for example, with a semiconductor memory or the like.
  • the memory unit may function as a work memory for the controller 43.
  • the display panel 2 emits display light of S-wave polarized light (first linearly polarized light L1).
  • the display light of the first linearly polarized light L1 emitted from the display panel 2 passes through the first phase difference plate 5 and is converted into light of the first circularly polarized light C1.
  • a part (for example, approximately 50%) of the first circularly polarized light C1 that passes through the first phase difference plate 5 passes through the semi-transmitting mirror 6.
  • the first circularly polarized light C1 that passes through the semi-transmitting mirror 6 passes through the second phase difference plate 7 and is converted into light of the second linearly polarized light L2 whose polarization direction is perpendicular to that of the first linearly polarized light L1 (i.e., P-wave polarized light).
  • the light of the second linearly polarized light L2 enters the reflective polarizer 8.
  • the reflective polarizer 8 reflects the light of P-wave polarized light and transmits the light of S-wave polarized light.
  • the light of the second linearly polarized light L2 that enters the reflective polarizer 8 is reflected by the reflective polarizer 8 and converted into light of the third linearly polarized light L3.
  • the light of the third linearly polarized light L3 passes through the second retardation plate 7 and is converted into the light of the second circularly polarized light C2.
  • a portion (e.g., approximately 50%) of the light of the second circularly polarized light C2 that passes through the second retardation plate 7 is reflected by the semi-transmitting mirror 6 and converted into the light of the third circularly polarized light C3.
  • the light of the third circularly polarized light C3 passes through the second retardation plate 7 and is converted into the light of the fourth linearly polarized light L4 whose polarization direction is parallel to that of the first linearly polarized light L1 (i.e., S-wave polarization).
  • the light of the fourth linearly polarized light L4 passes through the reflective polarizer 8 and is emitted to the outside.
  • the amount of light (brightness) of the light emitted from the display device 1 is, for example, approximately 25% of the amount of light (brightness) of the display light emitted from the display panel 2.
  • the first retardation plate 5, the semi-transmitting mirror 6, the second retardation plate 7, and the reflective polarizer 8 are held by a holding member (not shown) to maintain their relative positions. Air is interposed between the first retardation plate 5 and the second retardation plate 7 (i.e., between the first retardation plate 5 and the semi-transmitting mirror 6 and between the semi-transmitting mirror 6 and the second retardation plate 7).
  • the display device 1 is configured such that no member made of a resin material such as a polymer is provided between the first retardation plate 5 and the second retardation plate 7, and therefore the risk of deformation of the semi-transmitting mirror 6 when the resin material is hardened during the manufacturing process of the display device 1, and the risk of misalignment between the semi-transmitting mirror 6 and the first retardation plate 5 and the second retardation plate 7, etc. can be reduced.
  • resin materials such as polymers have retardation specific to the material, and can also reduce the risk of changing the polarization state of light transmitted through the resin material. As a result, the deterioration of display quality can be reduced.
  • the optical system 3 is an on-axis type optical system in which the optical axis of the incident light and the optical axis of the outgoing light are substantially aligned, so that the space occupied by the optical system 3 can be reduced, and as a result, the display device 1 can be made more compact.
  • the optical system 3 is a uniaxial type, distortion and brightness unevenness of the virtual image V viewed by the user 22 can be reduced, and the design of the optical system 3 becomes easier.
  • the optical path length of the light emitted from the display panel 2, transmitted through the semi-transmitting mirror 6, reflected by the reflective polarizer 8, and reaching the semi-transmitting mirror 6 may be shorter than the focal length of the semi-transmitting mirror 6. In this case, the user 22 can view a virtual image V.
  • the optical path length of the light emitted from the display panel 2, transmitted through the semi-transmitting mirror 6, reflected by the reflective polarizer 8, and reaching the semi-transmitting mirror 6 may be longer than the focal length of the semi-transmitting mirror 6. In this case, the user 22 can view a real image.
  • FIG. 2 for ease of illustration, the optical path of the light incident on the reflective polarizer 8 and the optical path of the light reflected by the reflective polarizer 8 are shown shifted in the height direction (Y-axis direction), and the optical path of the light incident on the semi-transparent mirror 6 and the optical path of the light reflected by the semi-transparent mirror 6 are shown shifted in the height direction (Y-axis direction), but in reality, the display light emitted from the display panel 2 propagates essentially on one axis, as shown in FIG. 37. This is also true for the optical paths shown in FIGS. 3 to 5, 9, 15, 16, 20 to 22, 24, and 30 to 32.
  • the display device 1 may have the first retardation plate 5, semi-transparent mirror 6, second retardation plate 7 and reflective polarizer 8 replaced with a convex lens 42.
  • the display device 1 may have an optical path length from the display panel 2 to the convex lens 42 that is shorter than the focal length of the convex lens 42. In this case, the virtual image V of the user 22 can be viewed.
  • the display device 1 may have an optical path length from the display panel 2 to the convex lens 42 that is longer than the focal length of the convex lens 42. In this case, the real image of the user 22 can be viewed.
  • the display panel 2 may display a mixed image including a left eye image and a right eye image having a parallax with each other, and may emit display light of the mixed image.
  • the display device 1 may include an optical element 9 located in the optical path of the display light emitted from the display panel 2.
  • the optical element 9 is configured to make a part of the display light of the mixed image reach one of the left eye and the right eye of the user 22, and make another part of the display light reach the other of the left eye and the right eye of the user 22.
  • the optical element 9 is configured to determine the respective light ray directions of the display light of the left eye image and the display light of the right eye image, so that at least a part of the display light of the left eye image reaches the left eye of the user 22, and at least a part of the display light of the right eye image reaches the right eye of the user 22. This allows the display device 1 to allow the user 22 to view a stereoscopic image.
  • the optical element 9 may be any element that allows a portion of the display light of the mixed image to reach one of the left and right eyes of the user 22 and allows the other portion of the display light to reach the other of the left and right eyes of the user 22, and may be, for example, a parallax barrier or a lenticular lens.
  • the parallax barrier may be formed of a liquid crystal panel.
  • the position of the optical element 9 is arbitrary within the display device 1.
  • the optical element 9 may be located between the display panel 2 and the first retardation plate 5, may be located after the reflective polarizer 8 in the emission direction of the display light, or may be located between the semi-transparent mirror 6 and the second retardation plate 7.
  • the display device of this embodiment differs from the display device of the above embodiment in the configuration of the optical system, but otherwise has a similar configuration. Therefore, the same reference symbols are used for similar configurations and detailed descriptions are omitted.
  • the display device 1A of this embodiment includes a display panel 2 and an optical system 10.
  • the display panel 2 has a display surface 2a, and displays a display image on the display surface 2a.
  • the optical system 10 projects the display light emitted from the display panel 2 into the visual field of the user 22 as a virtual image V.
  • the optical system 10 includes a first semi-transparent mirror 11, a first retardation plate 12, a second semi-transparent mirror 13, a second retardation plate 14, and a polarizing plate 15.
  • the first semi-transparent mirror 11, the first retardation plate 12, the second semi-transparent mirror 13, the second retardation plate 14, and the polarizing plate 15 are arranged in this order in the emission direction of the display light from the display panel 2.
  • the first retardation plate 12 is positioned opposite the reflecting surface 11a of the first semi-transparent mirror 11.
  • the first retardation plate 12 is positioned away from the display surface 2a in the emission direction of the display light from the display panel 2.
  • the second retardation plate 14 is positioned away from the first retardation plate 12 in the emission direction of the display light.
  • the first retardation plate 12 and the second retardation plate 14 are quarter-wave plates.
  • the first semi-transmitting mirror 11 is located between the display panel 2 and the first retardation film 12.
  • the first semi-transmitting mirror 11 may transmit a portion of the incident light and reflect the remainder.
  • the first semi-transmitting mirror 11 is a concave mirror having a concave reflective surface 11a facing the first retardation film 12.
  • the first semi-transmitting mirror 11 may be configured to transmit S-wave polarized light and reflect P-wave polarized light.
  • the first semi-transmitting mirror 11 may include a spherical shape, an aspherical shape, or a free-form shape on at least a portion of the reflective surface 11a.
  • the first semi-transmitting mirror 11 may be composed of, for example, a substrate and a plurality of thin metal wires (metal nanowire grid) located on the surface of the substrate.
  • the substrate may have a transmittance of 100% or close to 100% for light in the visible light band.
  • the substrate may be composed of, for example, a resin material, a glass material, etc.
  • the resin material may be, for example, an acrylic resin, a polycarbonate resin, etc.
  • the thin metal wires may be composed of a metal material such as aluminum, chromium, titanium oxide, etc.
  • the thin metal wires may be arranged along one direction.
  • the first semi-transmitting mirror 11 can transmit light components that vibrate in a direction perpendicular to the grid and can reflect light components that vibrate in a direction parallel to the grid.
  • the metal nanowire grid may be formed on the surface of the substrate facing the first retardation plate 12. In this example, the metal nanowire grid gives the first semi-transmitting mirror 11 a reflective polarizing function, but the first semi-transmitting mirror 11 may be a simple half mirror and a separate reflective polarizing plate may be provided.
  • the second semi-transmitting mirror 13 is located between the first retardation plate 12 and the second retardation plate 14.
  • the second semi-transmitting mirror 13 may transmit a portion of the incident light (e.g., approximately 50%) and reflect the remaining portion (e.g., approximately 50%).
  • the second semi-transmitting mirror 13 may be a plane mirror positioned such that the reflecting surface 13a faces the first retardation plate 12, as shown in FIG. 4.
  • the second semi-transmitting mirror 13 is also called a plane half mirror.
  • the second semi-transmitting mirror 13 may be integrated with the first retardation plate 12 and/or the second retardation plate 14, as shown in FIG. 31.
  • the second semi-transparent mirror 13 may be configured to include, for example, a substrate and a semi-transparent reflective layer located on the surface of the substrate.
  • the substrate may have a transmittance of 100% or close to 100% for light in the visible light band.
  • the substrate may be configured, for example, of inorganic glass, a resin material, etc.
  • the resin material may be, for example, an acrylic resin, a polycarbonate resin, etc.
  • the semi-transparent reflective layer may be a metal thin film.
  • the metal thin film may be configured, for example, of a metal material such as aluminum or chromium.
  • the semi-transparent reflective layer is not limited to a metal thin film, and may be, for example, a dielectric multilayer film, etc.
  • the polarizing plate 15 is positioned opposite the surface of the second retardation plate 14 opposite the surface facing the second semi-transmitting mirror 13. In other words, the polarizing plate 15 is positioned after the second retardation plate 14 in the emission direction of the display light from the display panel 2.
  • the polarizing plate 15 may transmit a portion of the incident light and absorb the remainder.
  • the polarizing plate 15 is configured to transmit P-wave polarized light and absorb S-wave polarized light.
  • the polarizing plate 15 may be integrated with the second retardation plate 14 as shown in FIG. 31.
  • the polarizing plate 15 may have the configuration of a known absorptive polarizing plate.
  • Known absorptive polarizing plates may be, for example, an iodine-based polarizing plate in which an iodine compound is adsorbed and aligned on a polyvinyl alcohol (PVA) film, or a dye-based polarizing plate in which a dichroic organic dye is adsorbed and aligned on a PVA film.
  • PVA polyvinyl alcohol
  • the optical function of the optical system 10 will be described.
  • the display light of S-wave polarized light (first linearly polarized light L1) emitted from the display panel 2 passes through the first semi-transparent mirror 11.
  • the display light of the first linearly polarized light L1 passes through the first phase difference plate 12 and is converted into the light of the first circularly polarized light C1.
  • the light of the first circularly polarized light C1 enters the second semi-transparent mirror 13.
  • a part of the light of the first circularly polarized light C1 (for example, approximately 50%) is reflected by the second semi-transparent mirror 13 and converted into the light of the second circularly polarized light C2.
  • the light of the second circularly polarized light C2 passes through the first phase difference plate 12 and is converted into the light of the second linearly polarized light L2 whose polarization direction is perpendicular to that of the first linearly polarized light L1 (i.e., P-wave polarized light).
  • the light of the second linearly polarized light L2 is reflected by the first semi-transparent mirror 11 and is converted into the light of the third linearly polarized light L3 whose polarization direction is perpendicular to that of the first linearly polarized light L1.
  • the third linearly polarized light L3 passes through the first phase difference plate 12 and is converted into the third circularly polarized light C3.
  • a portion (e.g., approximately 50%) of the third circularly polarized light C3 passes through the second semi-transparent mirror 13.
  • the third circularly polarized light C3 that passes through the second semi-transparent mirror 13 passes through the second phase difference plate 14 and is converted into the fourth linearly polarized light L4 whose polarization direction is perpendicular to the first linearly polarized light L1 (i.e., P-wave polarization).
  • the fourth linearly polarized light L4 passes through the polarizing plate 15 and is emitted to the outside.
  • the remaining portion (e.g., approximately 50%) of the first circularly polarized light C1 passes through the second semi-transparent mirror 13, then passes through the second retardation plate 14, and is converted into fifth linearly polarized light L5 whose polarization direction is parallel to the first linearly polarized light L1 (i.e., S-wave polarized light).
  • the fifth linearly polarized light L5 is absorbed by the polarizing plate 15 and is not emitted to the outside.
  • the fifth linearly polarized light L5 is light that is less transmitted through the polarizing plate 15. Therefore, the amount of light (brightness) of the light emitted from the display device 1A is, for example, approximately 25% of the amount of light (brightness) of the display light emitted from the display panel 2.
  • first retardation plate 12 and the second retardation plate 14 are quarter-wave plates, but the first retardation plate 12 and the second retardation plate 14 may be other wave plates or a combination thereof rather than quarter-wave plates, as long as some light is absorbed by the polarizing plate 15 and other light is transmitted through the polarizing plate 15. Also, the first retardation plate 12 and the second retardation plate 14 may be other wave plates or a combination thereof rather than quarter-wave plates, as long as some light is reflected by the first semi-transparent mirror 11 and other light is transmitted through the first semi-transparent mirror 11.
  • the first semi-transmitting mirror 11, the first retardation plate 12, the second semi-transmitting mirror 13, the second retardation plate 14, and the polarizing plate 15 are held by a holding member (not shown) to maintain their relative positions. Air is interposed between the first semi-transmitting mirror 11 and the first retardation plate 12.
  • the display device 1A is configured such that no member made of a resin material such as a polymer is provided between the first semi-transmitting mirror 11 and the first retardation plate 12. This reduces the risk of deformation of the first semi-transmitting mirror 11 when the resin material is hardened during the manufacturing process of the display device 1A, and of misalignment between the first semi-transmitting mirror 11 and the first retardation plate 12. As a result, deterioration in display quality can be reduced.
  • the optical system 10 is an on-axis type optical system in which the optical axis of the incident light and the optical axis of the outgoing light are substantially aligned, the space occupied by the optical system 10 can be reduced, and as a result, the display device 1A can be made more compact. Furthermore, because the optical system 10 is a uniaxial type, distortion and brightness unevenness of the virtual image V viewed by the user 22 can be reduced, and the design of the optical system 10 becomes easier.
  • the display device 1A may include an optical element 9, similar to the display device 1.
  • the display device 1A allows the user 22 to view a stereoscopic image.
  • the optical element 9 may be located between the display panel 2 and the first semi-transparent mirror 11, may be located after the polarizing plate 15 in the emission direction of the display light, or may be located between the first semi-transparent mirror 11 and the first retardation plate 12.
  • Display device 1A' of this example is different from display device 1A described above in the configuration (shape) of the second semi-transparent mirror, but otherwise has a similar configuration. Therefore, the same reference symbols are used for similar configurations and detailed descriptions are omitted.
  • the display device 1A' of this example includes a display panel 2 and an optical system 10, as shown in FIG. 5.
  • the optical system 10 includes a first semi-transparent mirror 11, a first retardation plate 12, a second semi-transparent mirror 13', a second retardation plate 14, and a polarizing plate 15.
  • the first semi-transparent mirror 11, the first retardation plate 12, the second semi-transparent mirror 13', the second retardation plate 14, and the polarizing plate 15 are arranged in this order in the emission direction of the display light from the display panel 2.
  • the second semi-transparent mirror 13' has a convex reflecting surface 13'a, which faces the first retardation plate 12.
  • the second semi-transparent mirror 13' is also called a convex half mirror.
  • the second semi-transparent mirror 13' may transmit a portion (e.g., approximately 50%) of the incident light and reflect the remaining portion (e.g., approximately 50%).
  • the second semi-transparent mirror 13' may be configured to include, for example, a substrate and a semi-transparent reflective layer located on the surface of the substrate.
  • the substrate may have a transmittance of 100% or close to 100% for light in the visible light band.
  • the substrate may be configured, for example, of inorganic glass, a resin material, etc.
  • the resin material may be, for example, an acrylic resin, a polycarbonate resin, etc.
  • the semi-transparent reflective layer may be a metal thin film.
  • the metal thin film may be configured, for example, of a metal material such as aluminum or chromium.
  • the semi-transparent reflective layer is not limited to a metal thin film, and may be, for example, a dielectric multilayer film, etc.
  • the optical system 10 may be configured so that the focal length of the second semi-transparent mirror 13' is greater than the distance between the display panel 2 and the second semi-transparent mirror 13'. In other words, the optical system 10 may be configured so that the second semi-transparent mirror 13' projects a reduced virtual image Q' (see FIG. 7) of the object (i.e., the display surface 2a). Furthermore, the optical system 10 may be configured so that the focal length of the first semi-transparent mirror 11 is greater than the distance between the virtual image Q' and the first semi-transparent mirror 11. In other words, the optical system 10 may be configured so that the first semi-transparent mirror 11 projects an enlarged virtual image V of the object (i.e., the virtual image Q'). In this case, it is possible to adjust the magnification and projection distance of the virtual image V while reducing the thickness of the optical system 10 in the depth direction (Z-axis direction).
  • the first semi-transmitting mirror 11, the first retardation film 12, the second semi-transmitting mirror 13', the second retardation film 14, and the polarizing film 15 are held by a holding member (not shown) to maintain their relative positions. Air is interposed between the first semi-transmitting mirror 11 and the first retardation film 12.
  • the display device 1A' is configured such that no member made of a resin material such as a polymer is provided between the first semi-transmitting mirror 11 and the first retardation film 12. This reduces the risk of deformation of the first semi-transmitting mirror 11 and misalignment between the first semi-transmitting mirror 11 and the first retardation film 12 occurring when the resin material is hardened during the manufacturing process of the display device 1A'. As a result, the deterioration of the display quality can be reduced.
  • the optical system 10 is an on-axis type optical system in which the optical axis of the incident light and the optical axis of the outgoing light are substantially aligned, the space occupied by the optical system 10 can be reduced, and as a result, the display device 1A' can be made more compact. Furthermore, because the optical system 10 is a uniaxial type, distortion and brightness unevenness of the virtual image V viewed by the user 22 can be reduced, and the design of the optical system 10 becomes easier.
  • the display device 1A' may also include an optical element 9, in which case it is possible for the user 22 to view a stereoscopic virtual image V.
  • the optical system 10 can be made thinner in the depth direction (Z-axis direction), so a thin display device can be provided.
  • the thinning of the optical system 10 will be described with reference to Figs. 6 and 7. Since the first semi-transmitting mirror 11 of the display devices 1A and 1A' has a concave reflecting surface 11a that reflects the display light emitted to the outside, the first semi-transmitting mirror 11 may be referred to as a concave mirror below.
  • the second semi-transmitting mirror 13 of the display device 1A has a planar reflecting surface 13a that reflects the display light emitted to the outside, the second semi-transmitting mirror 13 may be referred to as a planar mirror below. Since the second semi-transmitting mirror 13' of the display device 1A' has a convex reflecting surface 13'a that reflects the display light emitted to the outside, the second semi-transmitting mirror 13' may be referred to as a convex mirror below. Furthermore, the dimension of the optical system 10 in the depth direction (Z-axis direction) may be referred to as the thickness of the optical system 10.
  • FIG. 6 is a diagram explaining the projection of a virtual image V in the display device 1A.
  • the illuminator 4 and optical components that do not contribute to the projection distance (virtual image distance) and magnification of the virtual image V are omitted.
  • the concave mirror 11 is disposed so as to be in contact with the display panel 2 so that the distance between the display panel 2 and the concave mirror 11 can be regarded as "0".
  • the focal length of the concave mirror 11 is f
  • the distance between the concave mirror 11 and the plane mirror 13 is a/2.
  • the distance a/2 corresponds to the thickness of the optical system 10 of the display device 1A.
  • Display device 1A is configured to enlarge a virtual image Q on display surface 2a by plane mirror 13 using concave mirror 11 and project it as virtual image V.
  • virtual image Q is located on the opposite side of plane mirror 13 from concave mirror 11, and is at a distance a/2 from plane mirror 13.
  • Virtual image Q is an image of display surface 2a enlarged to the same size (1x).
  • the virtual image distance b and virtual image magnification m of the virtual image V are respectively expressed by the following formulas (1) and (2).
  • the virtual image distance b is the distance between the virtual image V and the concave mirror 11
  • the virtual image magnification m is the magnification of the virtual image V relative to the display surface 2a.
  • Table 1 shows configuration examples 1 and 2 of the display device 1A.
  • the focal length f, thickness a/2, and virtual image distance b shown in Table 1 are in mm.
  • Configuration examples 1 and 2 are configured so that the virtual image distance b is 200 mm and the virtual image magnification m is 2 or 3.
  • the thickness a/2 of the optical system 10 needs to be 50 mm (see configuration example 1), and in order to set the virtual image distance b to 200 mm and the virtual image magnification m to 3, the thickness a/2 of the optical system 10 needs to be 33.5 mm (see configuration example 2).
  • FIG. 7 is a diagram for explaining the projection of a virtual image V in the display device 1A'.
  • the illuminator 4 and optical components that do not contribute to the projection distance (virtual image distance) and magnification of the virtual image V are omitted.
  • the concave mirror 11 is disposed so as to be in contact with the display panel 2 so that the distance between the display panel 2 and the concave mirror 11 can be regarded as "0".
  • the focal length of the convex mirror 13' is f'
  • the focal length of the concave mirror 11 is f''
  • the distance between the concave mirror 11 and the convex mirror 13' is a'/2.
  • the distance a'/2 corresponds to the thickness of the optical system 10 of the display device 1A'.
  • the display device 1A' is configured to enlarge a virtual image Q' on the display surface 2a by a convex mirror 13' using a concave mirror 11 and project it as a virtual image V.
  • the virtual image Q' is located on the opposite side of the convex mirror 13' from the concave mirror 11.
  • the distance b' between the virtual image Q' and the convex mirror 13' is expressed by the following formula (3).
  • the magnification ratio m' of the virtual image Q' with respect to the display surface 2a is expressed by the following formula (4).
  • b' ⁇ a'/2 so the magnification ratio m' of the virtual image Q' is less than 1. Therefore, the virtual image Q' is a reduced virtual image of the display surface 2a.
  • b' 1/ ⁇ 1/f'+1/(a'/2) ⁇ ...(3)
  • m' b'/(a'/2)...(4)
  • the virtual image distance b'' and virtual image magnification m'' of the virtual image V are respectively expressed by the following formulas (5) and (6).
  • the virtual image distance b'' is the distance between the virtual image V and the concave mirror 11
  • the virtual image magnification m'' is the magnification of the virtual image V relative to the display surface 2a.
  • b'' 1/ ⁇ 1/(a'/2+b')-1/f'' ⁇ ...(5)
  • m'' (b'/(a'/2)) ⁇ b''/(a'/2+b')...(6)
  • Table 2 shows configuration examples 3 and 4 of the display device 1A'.
  • the focal lengths f', f'', thickness a'/2 and virtual image distance b'' shown in Table 2 are in mm.
  • Configuration examples 3 and 4 are configured to set the virtual image distance b'' to 200 mm and the virtual image magnification m'' to 2 or 3, similar to configuration examples 1 and 2.
  • the optical system 10 when the optical system 10 includes a convex mirror 13', the optical system 10 having a thickness a'/2 of 32 mm can set the virtual image distance b'' to 200 mm and the virtual image magnification m'' to 2, similar to configuration example 1 (see configuration example 3), and the optical system 10 having a thickness a'/2 of 25.5 mm can set the virtual image distance b'' to 200 mm and the virtual image magnification m'' to 3, similar to configuration example 2 (see configuration example 4). Therefore, according to the display device 1A', the optical system 10 can be made thinner, and as a result, a thin display device can be provided.
  • the optical system 10 can be designed to achieve them.
  • the design of the optical system 10 of the display device 1A' will be described below with reference to FIG. 8.
  • the illuminator 4, the first retardation plate 12, the second retardation plate 14, and the polarizing plate 15 are omitted, as in FIG. 7.
  • the concave mirror 11 is disposed so as to be in contact with the display panel 2 so that the distance between the display panel 2 and the concave mirror 11 can be regarded as "0".
  • the thickness of the optical system 10 is a1
  • the distance between the convex mirror 13' and the virtual image Q' is b1
  • the distance between the concave mirror 11 and the virtual image V is b2.
  • the magnification of the virtual image Q' with respect to the display surface 2a is m1, and the magnification of the virtual image V with respect to the virtual image Q' is m2. Furthermore, the focal length of the convex mirror 13' is f1, and the focal length of the concave mirror 11 is f2.
  • the magnification M of the virtual image V with respect to the display surface 2a is expressed as the product of the magnifications m1 and m2 as shown in the following formula (7).
  • the distance a2 between the concave mirror 11 and the virtual image Q' is expressed as the sum of the thickness a1 and the distance b1 as shown in the following formula (8).
  • M m1 ⁇ m2...(7)
  • a2 a1+b1...(8)
  • the magnification M is expressed by the following equation (9).
  • the display device 1A' can determine the focal lengths f1 and f2 (i.e., design the optical system 10) to realize these values.
  • the optical path length of the light emitted from the display panel 2, transmitted through the first semi-transmitting mirror 11, reflected by the second semi-transmitting mirror 13 and 13', and reaching the first semi-transmitting mirror 11 may be shorter than the focal length of the first semi-transmitting mirror 11. In this case, the user 22 can view a virtual image V.
  • the optical path length of the light emitted from the display panel 2, transmitted through the first semi-transmitting mirror 11, reflected by the second semi-transmitting mirror 13 and 13', and reaching the first semi-transmitting mirror 11 may be longer than the focal length of the first semi-transmitting mirror 11. In this case, the user 22 can view a real image.
  • the display device of this embodiment differs from the display device of the above embodiment in the configuration of the optical system, but otherwise has a similar configuration. Therefore, the same reference symbols are used for similar configurations and detailed descriptions are omitted.
  • the display device 1B of this embodiment includes a display panel 2 and an optical system 16.
  • the optical system 16 includes a first semi-transmitting mirror 17, a first retardation plate 18, a second semi-transmitting mirror 19, a second retardation plate 20, and a third semi-transmitting mirror 21.
  • the first semi-transmitting mirror 17, the first retardation plate 18, the second semi-transmitting mirror 19, the second retardation plate 20, and the third semi-transmitting mirror 21 are arranged in this order in the emission direction of the display light from the display panel 2.
  • the first retardation plate 18 is positioned opposite the reflecting surface 17a of the first semi-transparent mirror 17.
  • the first retardation plate 18 is positioned away from the display surface 2a in the emission direction of the display light from the display panel 2.
  • the second retardation plate 20 is positioned away from the first retardation plate 12 in the emission direction of the display light.
  • the first retardation plate 18 and the second retardation plate 20 are quarter-wave plates.
  • the first semi-transmitting mirror 17 is located between the display panel 2 and the first retardation plate 18.
  • the first semi-transmitting mirror 17 may transmit a portion of the incident light and reflect the remainder.
  • the first semi-transmitting mirror 17 may be configured to transmit S-wave polarized light and reflect P-wave polarized light.
  • the first semi-transmitting mirror 17 may be a concave mirror having a concave reflecting surface 17a facing the first retardation plate 18, as shown in FIG. 9.
  • the first semi-transmitting mirror 17 may include a spherical shape, an aspherical shape, or a free-form shape on at least a portion of the reflecting surface 17a.
  • the first semi-transmitting mirror 17 is composed of, for example, a substrate and a plurality of thin metal wires (metal nanowire grid) located on the surface of the substrate.
  • the substrate may have a transmittance of 100% or close to 100% for light in the visible light band.
  • the substrate may be composed of, for example, a resin material, a glass material, etc.
  • the resin material may be, for example, an acrylic resin, a polycarbonate resin, etc.
  • the thin metal wires may be composed of a metal material such as aluminum, chromium, titanium oxide, etc.
  • the thin metal wires may be arranged along one direction.
  • the first semi-transmitting mirror 17 can transmit light components that vibrate in a direction perpendicular to the grid and can reflect light components that vibrate in a direction parallel to the grid.
  • the metal nanowire grid may be formed on the surface of the substrate facing the first retardation plate 18. In this example, the metal nanowire grid gives the first semi-transmitting mirror 11 a reflective polarizing function, but the first semi-transmitting mirror 11 may be a simple half mirror and a separate reflective polarizing plate may be provided.
  • the second semi-transmitting mirror 19 is located between the first retardation plate 18 and the second retardation plate 20.
  • the second semi-transmitting mirror 13 may transmit a portion (e.g., approximately 50%) of the incident light and reflect the remaining portion (e.g., approximately 50%).
  • the second semi-transmitting mirror 19 may be a plane mirror having a reflecting surface 19a facing the first retardation plate 18 and a reflecting surface 19b facing the second retardation plate 20.
  • the second semi-transmitting mirror 19 is also called a plane half mirror.
  • the second semi-transmitting mirror 19 may be integrated with the first retardation plate 18 and/or the second retardation plate 20 as shown in FIG. 32.
  • the second semi-transmitting mirror 19 may be configured to include, for example, a substrate and a semi-transmitting layer located on the surface of the substrate.
  • the substrate may have a transmittance of 100% or close to 100% for light in the visible light band.
  • the substrate may be configured, for example, of inorganic glass, a resin material, etc.
  • the resin material may be, for example, an acrylic resin, a polycarbonate resin, etc.
  • the semi-transmitting layer may be a metal thin film.
  • the metal thin film may be configured, for example, of a metal material such as aluminum or chromium.
  • the semi-transmitting layer is not limited to a metal thin film and may be, for example, a dielectric multilayer film, etc.
  • the first retardation plate 18 and the second retardation plate 20 may be fixed to the second semi-transmitting mirror 19 by an optically transparent adhesive such as OCA (Optically Clear Adhesive).
  • the adhesive may be a material with small retardation.
  • the third semi-transmitting mirror 21 is positioned opposite the surface of the second retardation plate 20 opposite the surface facing the second semi-transmitting mirror 19.
  • the third semi-transmitting mirror 21 is positioned after the second retardation plate 20 in the emission direction of the display light from the display panel 2.
  • the third semi-transmitting mirror 21 may transmit a portion of the incident light and reflect the remainder.
  • the third semi-transmitting mirror 21 may be configured to reflect S-wave polarized light and transmit P-wave polarized light.
  • the third semi-transmitting mirror 21 may be a concave mirror having a concave reflecting surface 21a facing the second retardation plate 20, as shown in FIG. 9.
  • the third semi-transmitting mirror 21 may include a spherical shape, an aspherical shape, or a free-form shape on at least a portion of the reflecting surface 21a.
  • the third semi-transmitting mirror 21 is composed of, for example, a substrate and a plurality of thin metal wires (metal nanowire grid) located on the surface of the substrate.
  • the substrate may have a transmittance of 100% or close to 100% for light in the visible light band.
  • the substrate may be composed of, for example, a resin material, a glass material, etc.
  • the resin material may be, for example, an acrylic resin, a polycarbonate resin, etc.
  • the thin metal wires may be composed of a metal material such as aluminum, chromium, titanium oxide, etc.
  • the thin metal wires may be arranged along one direction.
  • the third semi-transmitting mirror 21 can transmit light components that vibrate in a direction perpendicular to the grid and can reflect light components that vibrate in a direction parallel to the grid.
  • the metal nanowire grid may be formed on the surface of the substrate facing the second retardation plate 20. In this example, the metal nanowire grid gives the third semi-transmitting mirror 21 a reflective polarizing function, but the third semi-transmitting mirror 21 may be a simple half mirror and a separate reflective polarizing plate may be provided.
  • the display light emitted from the display panel 2 may travel along path P1 or path P2 and be emitted to the outside.
  • the display light of S-wave polarized light (first linearly polarized light L1) emitted from the display panel 2 passes through the first semi-transparent mirror 17.
  • the light of the first linearly polarized light L1 passes through the first phase difference plate 18 and is converted into the light of the first circularly polarized light C1.
  • the light of the first circularly polarized light C1 is incident on the second semi-transparent mirror 19.
  • a part of the light of the first circularly polarized light C1 (for example, approximately 50%) is reflected by the second semi-transparent mirror 19 and converted into the light of the second circularly polarized light C2.
  • the light of the second circularly polarized light C2 passes through the first phase difference plate 18 and is converted into the light of the second linearly polarized light L2 whose polarization direction is perpendicular to that of the first linearly polarized light L1 (i.e., P-wave polarized light).
  • the second linearly polarized light L2 is reflected by the first semi-transparent mirror 17 and converted into a third linearly polarized light L3 whose polarization direction is orthogonal to the first linearly polarized light L1 (i.e., P-wave polarized light).
  • the third linearly polarized light L3 passes through the first phase difference plate 18 and is converted into a third circularly polarized light C3.
  • the third circularly polarized light C3 enters the second semi-transparent mirror 19. A portion (e.g., approximately 50%) of the third circularly polarized light C3 passes through the second semi-transparent mirror 19.
  • the third circularly polarized light C3 that passes through the second semi-transparent mirror 19 passes through the second phase difference plate 20 and is converted into a fourth linearly polarized light L4 whose polarization direction is orthogonal to the first linearly polarized light L1 (i.e., P-wave polarized light).
  • the fourth linearly polarized light L4 passes through the third semi-transparent mirror 21 and is emitted to the outside.
  • the remaining portion (e.g., approximately 50%) of the light of the first circularly polarized light C1 incident on the second semi-transparent mirror 19 is transmitted through the second semi-transparent mirror 19.
  • the light of the first circularly polarized light C1 transmitted through the second semi-transparent mirror 19 is transmitted through the second phase difference plate 20 and converted into light of the fifth linearly polarized light L5 whose polarization direction is parallel to the first linearly polarized light L1 (i.e., S-wave polarization).
  • the light of the fifth linearly polarized light L5 is reflected by the third semi-transparent mirror 21 and converted into light of the sixth linearly polarized light L6 whose polarization direction is parallel to the first linearly polarized light L1 (i.e., S-wave polarization).
  • the light of the sixth linearly polarized light L6 is transmitted through the second phase difference plate 20 and converted into light of the fourth circularly polarized light C4.
  • the light of the fourth circularly polarized light C4 is incident on the second semi-transparent mirror 19.
  • a portion of the fourth circularly polarized light C4 (e.g., approximately 50%) is reflected by the second semi-transparent mirror 19 and converted into the fifth circularly polarized light C5.
  • the fifth circularly polarized light C5 passes through the second retardation plate 20 and is converted into the seventh linearly polarized light L7 whose polarization direction is perpendicular to the first linearly polarized light L1 (i.e., P-wave polarization).
  • the seventh linearly polarized light L7 passes through the third semi-transparent mirror 21 and is emitted to the outside.
  • the display light emitted from display panel 2 travels along path P1 or path P2 and is emitted to the outside.
  • the amount of light (brightness) of the light emitted from display device 1B is, for example, approximately 50% of the amount of light (brightness) of the display light emitted from display panel 2.
  • Display device 1B can increase the light utilization efficiency and improve the brightness of the light emitted to the outside.
  • first phase difference plate 18 and the second phase difference plate 20 are quarter-wave plates, but the first phase difference plate 18 and the second phase difference plate 20 may not be quarter-wave plates but may be other wave plates or a combination thereof, as long as some light is reflected by the first semi-transparent mirror 17 and other light is transmitted through the first semi-transparent mirror 17. Also, the first phase difference plate 18 and the second phase difference plate 20 may not be quarter-wave plates but may be other wave plates or a combination thereof, as long as some light is reflected by the third semi-transparent mirror 21 and other light is transmitted through the third semi-transparent mirror 21.
  • the first semi-transmitting mirror 17, the first retardation plate 18, the second semi-transmitting mirror 19, the second retardation plate 20, and the third semi-transmitting mirror 21 are held by a holding member (not shown) to maintain their relative positions. Air is interposed between the first semi-transmitting mirror 17 and the first retardation plate 18 and between the third semi-transmitting mirror 21 and the second retardation plate 20.
  • the display device 1B is configured such that no member made of a resin material such as a polymer is provided between the first semi-transmitting mirror 17 and the first retardation plate 18 and between the third semi-transmitting mirror 21 and the second retardation plate 20, thereby reducing the risk of deformation of the first semi-transmitting mirror 11 and misalignment between the first semi-transmitting mirror 11 and the first retardation plate 12. As a result, the deterioration of the display quality can be reduced.
  • a resin material such as a polymer
  • the optical system 16 is an on-axis type optical system in which the optical axis of the incident light and the optical axis of the outgoing light are substantially aligned, the space occupied by the optical system 16 can be reduced, and as a result, the display device 1B can be made more compact. Furthermore, because the optical system 16 is a uniaxial type, distortion and brightness unevenness of the virtual image V viewed by the user 22 can be reduced, and the design of the optical system 16 becomes easier.
  • Display device 1B may be configured such that the focal length of first semi-transparent mirror 17 is equal to the focal length of third semi-transparent mirror 21, and second semi-transparent mirror 19 is a plane mirror.
  • the virtual image formed by light traveling along path P1 and the virtual image formed by light traveling along path P2 substantially coincide with each other, improving display quality.
  • the optical path length of light emitted from the display panel 2, transmitted through the first semi-transmitting mirror 17, reflected by the second semi-transmitting mirror 19, and reaching the first semi-transmitting mirror 17 is shorter than the focal length of the first semi-transmitting mirror 17, and the optical path length of light emitted from the display panel 2, transmitted through the first semi-transmitting mirror 17, transmitted through the second semi-transmitting mirror 19, and reaching the third semi-transmitting mirror 21 is shorter than the focal length of the first semi-transmitting mirror 17.
  • the optical path length of the light emitted from the display panel 2, transmitted through the first semi-transmitting mirror 17, reflected by the second semi-transmitting mirror 19, and reaching the first semi-transmitting mirror 17 may be greater than the focal length of the first semi-transmitting mirror 17, and the optical path length of the light emitted from the display panel 2, transmitted through the first semi-transmitting mirror 17, transmitted through the second semi-transmitting mirror 19, and reaching the third semi-transmitting mirror 21 may be greater than the focal length of the first semi-transmitting mirror 17. In this case, it is possible for the user 22 to visually recognize a real image.
  • the imaging device 100 of this embodiment includes display devices 1, 1A, 1A', and 1B.
  • the imaging device 100 allows the user 22 to view the display light emitted from the display panel 2 as a virtual image V. Since the imaging device 100 includes the display devices 1, 1A, 1A', and 1B, a small imaging device can be realized, and the user 22 can view the virtual image V with improved display quality. In particular, when the imaging device 100 includes the display device 1A', a thin imaging device can be realized.
  • the imaging device 100 may allow the user 22 to view the display light emitted from the display panel 2 as a real image.
  • the imaging device 100 may be mounted on a moving object 23 as shown in FIG. 10.
  • the moving object 23 may be a vehicle.
  • FIG. 10 shows a case where the vehicle is a passenger car, but the vehicle is not limited to a passenger car, and may be an automobile such as a truck, a bus, or a trolley bus.
  • the display devices 1, 1A, 1A', 1B may be positioned at any position inside the moving object 23.
  • the display devices 1, 1A, 1A', 1B may be positioned on the dashboard (instrument panel), inside the dashboard, on the ceiling of the passenger compartment, on the A-pillar, etc. Part of the configuration of the imaging device 100 may be shared with other devices and parts provided in the moving object 23.
  • the imaging device 100 may include a camera 102 that captures an image of the rear view of the moving object 23.
  • the camera 102 may include, for example, a CCD (Charge Coupled Device) imaging element or a CMOS (Complementary Metal Oxide Semiconductor) imaging element.
  • the imaging device 100 and the camera 102 are connected via wired and/or wireless communication. If the moving object 23 is a vehicle, the imaging device 100 and the camera 102 may be connected via a vehicle network such as a CAN (Control Area Network).
  • a vehicle network such as a CAN (Control Area Network).
  • the imaging device 100 may be configured to display at least a part of the captured image captured by the camera 102 on the display panel 2.
  • the imaging device 100 allows the user 22 (driver of the moving body 23) to visually recognize the rear view of the moving body 23 as a virtual image V imaged on the far side of the imaging device 100.
  • the user 22 can visually recognize the rear view of the moving body 23 without significantly changing the gaze distance (gazing point) while driving the moving body 23, making it easier to visually recognize the virtual image V and improving driving safety.
  • the imaging device 100 is a small imaging device, even if it is placed in the driver's cab of the moving body 23, it does not occupy a large volume in the cab and is unlikely to interfere with driving.
  • the imaging device 100 mounted on the moving body 23 and configured to allow the user 22 to visually recognize the rear view of the moving body 23 as a virtual image V is also called a digital rearview mirror.
  • the display devices 1, 1A, 1A', 1B may include an optical element 9 (see FIG. 3).
  • the imaging device 100 may be configured such that the display panel 2 displays a mixed image including a left eye image and a right eye image having parallax with respect to each other, emits a display light for the left eye image and a display light for the right eye image, and the optical element 9 causes the display light for the left eye image to reach the left eye of the user 22 and the display light for the right eye image to reach the right eye of the user 22.
  • the display light for the left eye image and the display light for the right eye image emitted from the display panel 2 can be viewed by the user 22 as a stereoscopic virtual image V.
  • the imaging device 100 may include a reflective optical element 101, as shown in FIG. 11.
  • the imaging device 100 may be configured such that the display devices 1, 1A, 1A', 1B emit display light toward the reflective optical element 101, and the reflective optical element 101 causes a portion of the display light to reach the eye of the user 22.
  • the imaging device 100 may also use the windshield 24 of the moving object 23 as the reflective optical element 101.
  • the imaging device 100 may be applied to a digital side mirror.
  • the imaging device 100 may include a display device 1, 1A, 1A', 1B (hereinafter also referred to as the left display device 1L) located on the left A-pillar of the moving body 23, a camera 102 (hereinafter also referred to as the left camera 102L) that captures the left rear of the moving body 23, a display device 1, 1A, 1A', 1B (hereinafter also referred to as the right display device 1R) located on the right A-pillar of the moving body 23, and a camera 102 (hereinafter also referred to as the right camera 102R) that captures the right rear of the moving body 23, as shown in FIG. 12.
  • the left display device 1L may allow the user 22 to view the image of the left rear of the moving body 23 captured by the left camera 102L as a virtual image V (hereinafter also referred to as the virtual image V2).
  • the right-side display device 1R may allow the user 22 to view an image of the right rear of the moving object 23 captured by the right-side camera 102R as a virtual image V (hereinafter also referred to as virtual image V3).
  • the image may be a moving image (also referred to as a video) or a still image.
  • the left-side camera 102L may be located in the same position as the left door mirror, and the right-side camera 102R may be located in the same position as the right door mirror.
  • the imaging device 100 may be configured so that the distance between the eyes (or eye box) of the user 22 and each of the virtual images V2 and V3 is approximately the same.
  • the user 22 can check the situation on the left rear and right rear of the moving body 23 without significantly changing the gaze distance (the distance between the eyes of the user 22 and the gaze point at which the user 22 is gazing). This can improve driving safety.
  • the eye box refers to the area in real space where the eyes of the user 22 are assumed to be present.
  • the imaging device 100 may be configured so that the distance between the eyes (or eyebox) of the user 22 and each of the virtual images V1 to V3 is approximately the same. In this case, the user 22 can check the situation immediately behind, to the left rear, and to the right rear of the moving object 23 without significantly changing the gaze distance. This can therefore improve driving safety.
  • the imaging device 100 may be applied to a cluster 29 in the dashboard of a moving object 23 (see FIG. 12).
  • the display device 1, 1A, 1A', 1B may allow the user 22 to view an image showing information related to driving, such as vehicle speed, engine speed, remaining fuel, etc., as a virtual image V (hereinafter also referred to as virtual image V4).
  • the imaging device 100 may be applied to a CID (Center Information Display) 30 (see FIG. 12).
  • the display devices 1, 1A, 1A', 1B may be arranged in a center cluster of a mobile object 23, and an image showing information on navigation, the in-vehicle environment (e.g., settings of the air conditioning system, audio system, etc.), etc. may be visually recognized by the user 22 as a virtual image V (hereinafter also referred to as virtual image V5).
  • the imaging device 100 may be configured so that the distance between the eye (or eye box) of the user 22 and each of the virtual images V4 and V5 is approximately the same.
  • the user 22 can check information related to the operation of the mobile object 23, as well as information related to navigation and the in-vehicle environment, without significantly changing the gaze distance. This can therefore improve driving safety.
  • the imaging device 100 may be configured so that the distance between the eyes (or eyebox) of the user 22 and each of the virtual images V1 to V5 is approximately the same.
  • the user 22 can see directly behind, to the left rear, and to the right rear of the moving object 23 without significantly changing the gaze distance, and can also check information related to the operation of the moving object 23, navigation, the in-vehicle environment, etc. Therefore, driving safety can be improved.
  • the imaging device 100 may be applied to a PID (Passenger Information Display) 31 (see FIG. 12).
  • the display devices 1, 1A, 1A', 1B may be arranged on the dashboard near the passenger seat, and may allow the passenger to view images of entertainment content and images showing information about the audio system, air conditioning system, etc. as a virtual image V.
  • the imaging device 100 may be applied to an RSE (Rear Seat Entertainment) system 32 (see FIG. 10).
  • RSE Rear Seat Entertainment
  • the display devices 1, 1A, 1A', 1B may be arranged on the back of the front seats, and images of entertainment content and images showing information about the audio equipment, air conditioning equipment, etc. may be visually recognized as virtual images V by passengers seated in the rear seats of the vehicle 23.
  • the display devices 1, 1A, 1A', 1B may be provided with a drive unit that adjusts the relative positions between the display panel 2, the semi-transmitting mirror 6, the first semi-transmitting mirror 11, 17, and the second semi-transmitting mirror 13, 13', 21 in the depth direction.
  • Image data of the display image displayed on the display panel 2 may include depth information that indicates the depth (distance in the depth direction) from a reference position.
  • the reference position may be, for example, the position of the display panel 2.
  • the virtual image display device 100 may be configured to adjust the distance between the display panel 2, the semi-transmitting mirror 6, the first semi-transmitting mirror 11, 17, and the second semi-transmitting mirror 13, 13', 21 based on the depth information included in the image data, and change the imaging position of the virtual image V in the depth direction.
  • the drive unit may be, for example, an electric slider, an electric cylinder, etc.
  • the drive unit may be configured so that the user 22 can manually adjust the relative positions between the display panel 2, the semi-transparent mirror 6, the first semi-transparent mirrors 11 and 17, and the second semi-transparent mirrors 13, 13' and 21.
  • Figures 13 and 14 are top views showing other examples of display devices of the present disclosure. Note that the first retardation plate 5, the second retardation plate 7, and the optical element 9 are omitted in Figures 13 and 14.
  • the display device 1 will be described as an example, but the same applies to the display devices 1A, 1A', and 1B.
  • the display device 1 can constitute a part of the imaging device 100 (digital rearview mirror).
  • a normal rearview mirror that is, a rearview mirror using a mirror
  • the image seen by the user's left eye also called the left eyeglass image
  • the image seen by the right eye also called the right eyeglass image
  • the user recognizes the left eyeglass image and the right eyeglass image as mirror images seen by both eyes due to the cognitive function of the brain.
  • the display device 1 may be configured so that the virtual image projected into the visual field of the user 22 has a binocular visible area (virtual image V in FIGS. 13 and 14) that is viewed by the left eye 22L and right eye 22R of the user 22, a left eye visible area VLa that is viewed only by the left eye 22L, and a right eye visible area VRa that is viewed only by the right eye 22R.
  • a binocular visible area virtual image V in FIGS. 13 and 14
  • VLa left eye visible area
  • VRa right eye visible area
  • the left eye virtual image VL may have a left eye visible area VLa that is viewed only by the left eye 22L
  • the right eye virtual image VR may have a right eye visible area VRa that is viewed only by the right eye 22R.
  • the left eye visible area VLa is located to the right of the binocular visible area
  • the right eye visible area VRa is located to the left of the binocular visible area.
  • the display device 1 may be configured such that the right end 6R of the semi-transparent mirror 6 that is visible to the user 22 is located on a straight line connecting the left eye 22L and the right end VLR of the left-eye virtual image VL, and the left end 6L of the semi-transparent mirror 6 that is visible to the user 22 is located on a straight line connecting the right eye 22R and the left end VRL of the right-eye virtual image VR.
  • the range observed by the user 22 through the left eye virtual image VL is different from the range observed by the user 22 through the right eye virtual image VR, similar to the left and right eyeglass images in a normal rearview mirror. Therefore, the user 22 can recognize the left eye virtual image VL and the right eye virtual image VR as virtual images V viewed by both eyes 22L, 22R through the cognitive function of the brain, similar to when using a normal rearview mirror. This reduces the risk of the user 22 feeling uncomfortable.
  • the size of the reflective surface on the display surface 2a side of the reflective polarizer 8 may be equal to or larger than the size of the display surface 2a.
  • the reflective polarizer 8 can reflect the image of the entire display surface 2a toward the semi-transparent mirror 6.
  • the display device 1 may be configured so that the virtual image VD (hereinafter also referred to as the display surface virtual image) when the image of the entire display surface 2a is projected into the field of view of the user 22 includes the left eye virtual image VL and the right eye virtual image VR.
  • the viewing area R can be controlled, for example, by controlling the size of the display surface 2a, the magnification of the virtual image, etc.
  • the image display area (area where the image is actually displayed) A on the display surface 2a it is also possible to control the size of the peering area R.
  • the peering area R By making the image display area A larger, the peering area R can be enlarged. By making the image display area A smaller, the peering area R can be reduced.
  • the image display area A becomes smaller than a predetermined threshold area, the peering area R disappears, and the left eye virtual image VL and right eye virtual image VR can be made the same virtual image.
  • the display device 1 may include a housing 27.
  • the housing 27 may have an opening 28 on its front side (the side of the user 22).
  • the virtual image V may be larger than the opening 28.
  • the size of the viewing area R can also be controlled by the size of the opening 28.
  • FIG. 14 by appropriately designing the size of the opening 28, it is possible to form a left eye virtual image VL including an area that cannot be seen by the right eye 22R, and a right eye virtual image VR including an area that cannot be seen by the left eye 22L.
  • the size of the opening 28 it is possible to form the viewing area R and control the size of the viewing area R.
  • the size of the semi-transparent mirror 6 only needs to be large enough to project the image of the entire display surface 2a into the visual field of the user 22, which makes it easier to design the optical system 3.
  • the display devices 1A, 1A', and 1B may be configured so that the virtual image projected into the field of view of the user 22 has a binocular visible area visible with the left eye 22L and the right eye 22R, a left eye visible area visible only with the left eye 22L, and a right eye visible area visible only with the right eye 22R. In this case, the risk of causing discomfort to the user 22 can be reduced.
  • the display devices 1A and 1A' may be configured so that the right end of the first semi-transparent mirror 11 visible to the user 22 is located on a straight line connecting the left eye 22L and the right end of the left eye virtual image, and the left end of the first semi-transparent mirror 11 visible to the user 22 is located on a straight line connecting the right eye 22R and the left end of the right eye virtual image.
  • the display device 1B may be configured such that the right ends of the first semi-transmitting mirror 17 and the third semi-transmitting mirror 21 that are visible to the user 22 are located on a straight line connecting the left eye 22L and the right end of the left-eye virtual image, and the left ends of the first semi-transmitting mirror 17 and the third semi-transmitting mirror 21 that are visible to the user 22 are located on a straight line connecting the right eye 22R and the left end of the right-eye virtual image.
  • the display devices 1A, 1A', and 1B may be configured to have a viewing region R.
  • the display devices 1A, 1A', and 1B may be configured such that the size of the viewing region R is controlled by the image display region A, or may be configured such that the size of the viewing region R is controlled by the opening 28 of the housing 27.
  • Figures 15 and 16 are cross-sectional views illustrating the other examples of display devices
  • Figures 17A to 17D and 18A to 18D are diagrams illustrating the optical system in the other examples of display devices
  • Figure 19 is a graph illustrating the optical system in the other examples of display devices.
  • display device 1 will be used as an example for the description, but the same applies to display devices 1A and 1A'.
  • the display device 1 is configured so that when the user 22 is located in front of the display device 1, the light of the second linearly polarized light L2 is reflected by the reflective polarizer 8 and does not exit from the display device 1 (see Figures 2 and 3).
  • the display device 1 is configured so that, when viewed from the front of the display device 1, the transmission axis of the polarizer on the front side (user 22 side) of the display panel 2 (liquid crystal panel) and the transmission axis of the reflective polarizer 8 are perpendicular (in a crossed Nicol arrangement).
  • the light of the second linearly polarized light L2 is not exited from the display device 1, and the light of the fourth linearly polarized light L4 is exited from the display device 1.
  • the user 22 does not directly view the display panel 2, but views the reflected image reflected by the semi-transparent mirror 6 as a virtual image V.
  • the crossed Nicol arrangement between the transmission axis of the front polarizer of the display panel 2 and the transmission axis of the reflective polarizer 8 is lost, and some of the light of the second linearly polarized light L2 may be transmitted through the reflective polarizer 8.
  • the user 22 may be able to see both the real image seen by looking directly at the display panel 2 and the virtual image V reflected by the semi-transparent mirror 6, which may degrade the display quality of the display device 1.
  • the display device 1 of this example has a third retardation plate 25 located between the display panel 2 and the reflective polarizer 8, as shown in Figures 15 and 16. This allows the relative angle between the transmission axis of the front polarizer of the display panel 2 and the transmission axis of the reflective polarizer 8 to approach a crossed Nicol arrangement even when the user 22 is not located in front of the display device 1, thereby reducing degradation in the display quality of the display device 1.
  • the third retardation plate 25 may be a 1/2 wavelength plate (half wavelength plate), 1/4 wavelength plate, 1/8 wavelength plate, 1/16 wavelength plate, etc., or may be a wavelength plate that imparts another phase difference.
  • the optical axis of the third retardation plate 25 may be approximately parallel or approximately perpendicular to the transmission axis of the reflective polarizer 8.
  • the display device 1 of this example may further include a fourth retardation plate 26 located between the display panel 2 and the reflective polarizer 8, as shown in Figs. 15 and 16.
  • a fourth retardation plate 26 located between the display panel 2 and the reflective polarizer 8, as shown in Figs. 15 and 16.
  • the fourth retardation plate 26 may be a 1/2 wavelength plate (half wavelength plate), 1/4 wavelength plate, 1/8 wavelength plate, 1/16 wavelength plate, etc., or may be a wavelength plate that imparts another phase difference.
  • the optical axis of the fourth retardation plate 26 may be approximately parallel or approximately perpendicular to the transmission axis of the reflective polarizer 8.
  • the third retardation film 25 and the fourth retardation film 26 may be located anywhere between the display panel 2 and the reflective polarizer 8. If no other optical elements are located between the third retardation film 25 and the fourth retardation film 26, the third retardation film 25 and the fourth retardation film 26 may be in contact with each other. In this case, the thickness of the optical system 3 in the depth direction can be reduced.
  • One of the third retardation film 25 and the fourth retardation film 26 may be a quarter-wave plate and the other a half-wave plate. In this case, degradation of the display quality of the display device 1 can be effectively reduced. Both the third retardation film 25 and the fourth retardation film 26 may be half-wave plates. In this case, degradation of the display quality of the display device 1 can be more effectively reduced.
  • 17A, 17B, 17C, and 17D are Poincaré spheres showing the optical functions (effects on the polarization state of light) of the third retardation plate 25 and the fourth retardation plate 26 when the third retardation plate 25 and the fourth retardation plate 26 are half-wave plates.
  • 17A and 17B are diagrams for explaining the optical function of the third retardation plate 25
  • 17C and 17D are diagrams for explaining the optical function of the fourth retardation plate 26.
  • 17A and 17C show diagrams of the Poincaré sphere as viewed from the north pole (S3 axis direction)
  • 17B and 17D show diagrams of the Poincaré sphere as viewed from the side (S1 axis direction).
  • S LCD shows the polarization state of light immediately after it is emitted from the display panel 2.
  • S 25 indicates the polarization state of the light that has passed through the third retardation plate 25
  • S 26 indicates the polarization state of the light that has passed through the fourth retardation plate 26. It can be said that S 26 indicates the polarization state of the light immediately before it enters the reflective polarizer 8.
  • S RP indicates the polarization state of the light that passes through the reflective polarizer 8 with a transmittance of substantially 100%
  • S AP is the antipodal point of S RP (a point symmetrical with respect to the center of the Poincaré sphere).
  • 18A, 18B, 18C, and 18D are Poincaré spheres showing the optical functions of the third retardation plate 25 and the fourth retardation plate 26 when the third retardation plate 25 is a quarter-wave plate and the fourth retardation plate 26 is a half-wave plate.
  • 18A and 18B are diagrams explaining the optical function of the third retardation plate 25
  • 18C and 18D are diagrams explaining the optical function of the fourth retardation plate 26.
  • 18A and 18C show diagrams of the Poincaré sphere seen from the north pole (S3 axis direction)
  • 18B and 18D show diagrams of the Poincaré sphere seen from the side (S1 axis direction).
  • S LCD , S 25 , S 26 , S RP , and S AP are as described above.
  • FIG. 19 is a graph showing the relationship between the light transmittance of an optical system in which a third retardation plate 25 and a fourth retardation plate 26 are inserted between polarizers PP1 and PP2 whose transmission axes are perpendicular to each other, and the phase difference of the third retardation plate 25 and the fourth retardation plate 26.
  • FIG. 19 shows the results obtained by simulation.
  • the incident light was green light with a wavelength ⁇ of 550 nm.
  • the polarizer PP1, the third retardation plate 25, the fourth retardation plate 26, and the polarizer PP2 are arranged in this order in the traveling direction of the incident light.
  • the polarizer PP1 imitates the front polarizer of the display panel 2, and the polarizer PP2 imitates the reflective polarizer 8.
  • the solid line in the graph of FIG. 19 shows the transmittance when the phase difference of the fourth retardation plate 26 is fixed at 0 nm and the phase difference of the third retardation plate 25 is changed, and is minimum when the phase difference of the third retardation plate 25 is about 275 nm (half the wavelength ⁇ of the incident light).
  • the dashed line in the graph of FIG. 19 shows the transmittance when the phase difference of the third retardation plate 25 is fixed at 270 nm and the phase difference of the fourth retardation plate 26 is changed, and is minimum when the phase difference of the fourth retardation plate 26 is about 275 nm (half the wavelength of the incident light).
  • the display device 1 can effectively reduce the risk that the user 22 will see a real image when looking directly at the display panel 2, and can effectively reduce a deterioration in the display quality of the display device 1.
  • the display device 1 can effectively reduce the risk that the user 22 will see a real image when looking directly at the display panel 2, and can effectively reduce a deterioration in the display quality of the display device 1, as long as the third retarder 25 can impart a phase difference greater than 0 nm (i.e., a non-zero) to the light incident on the third retarder 25.
  • the display devices 1A and 1A' may have a third retardation plate 25 located between the display panel 2 and the polarizing plate 15. In this case, it is possible to reduce the risk that the user 22 will see a real image when looking directly at the display panel 2, and it is possible to reduce the deterioration of the display quality of the display devices 1A and 1A'.
  • the display devices 1A and 1A' may further have a fourth retardation plate 26 located between the display panel 2 and the polarizing plate 15. In this case, it is possible to further reduce the risk that the user 22 will see a real image when looking directly at the display panel 2, and it is possible to further reduce the deterioration of the display quality of the display devices 1A and 1A'.
  • the third retardation plate 25 and the fourth retardation plate 26 may be a 1/2 wavelength plate (half wavelength plate), a 1/4 wavelength plate, a 1/8 wavelength plate, a 1/16 wavelength plate, etc., or may be a wavelength plate that imparts other phase differences.
  • One of the third retardation plate 25 and the fourth retardation plate 26 may be a quarter-wave plate and the other a half-wave plate. In this case, the degradation of the display quality of the display device 1 can be effectively reduced.
  • Both of the third retardation plate 25 and the fourth retardation plate 26 may be half-wave plates. In this case, the degradation of the display quality of the display device 1 can be more effectively reduced.
  • the third retardation plate 25 and the fourth retardation plate 26 may be located between the display panel 2 and the polarizing plate 15, and their positions are arbitrary.
  • Figure 20 is a cross-sectional view showing another example of the display device 1A'
  • Figure 21 is a cross-sectional view showing another example of the display device 1A.
  • the second semi-transmitting mirror 13' of the display device 1A' may be configured to include a holographic optical element (HOE).
  • HOE holographic optical element
  • the optical function of the second semi-transmitting mirror 13' can be realized by a flat optical element, and the thickness of the second semi-transmitting mirror 13' in the depth direction (Z-axis direction) can be reduced.
  • the display device 1A' can be made smaller in the depth direction.
  • the second semi-transmitting mirror 13' is a flat optical element, the distance between the second semi-transmitting mirror 13' and the second retardation plate 14 can be reduced, or the second semi-transmitting mirror 13' and the second retardation plate 14 can be brought into contact with each other, making it possible to further reduce the size of the display device 1A' in the depth direction.
  • the first semi-transmitting mirror 11 of the display device 1A' may be configured to include a HOE.
  • the optical function of the first semi-transmitting mirror 11 can be realized by a flat optical element, and the thickness of the first semi-transmitting mirror 11 in the depth direction can be reduced.
  • the display device 1A' can be made smaller in the depth direction.
  • the first semi-transmitting mirror 11 is a flat optical element, the distance between the first semi-transmitting mirror 11 and the display panel 2 can be reduced, or the first semi-transmitting mirror 11 and the display panel 2 can be brought into contact with each other, making it possible to further reduce the size of the display device 1A' in the depth direction.
  • the first semi-transparent mirror 11 including the HOE may be configured to have polarization selectivity.
  • the first semi-transparent mirror 11 including the HOE may have a plurality of metal fine wires (metal nanowire grid) formed on the surface facing the display panel 2 or the surface facing the first retardation plate 12, which realizes polarization selectivity that transmits S-wave polarized light and reflects P-wave polarized light. In this case, the decrease in brightness of the virtual image V viewed by the user 22 can be reduced.
  • the first semi-transmitting mirror 11 of the display device 1A may be configured to include a HOE.
  • the optical function of the first semi-transmitting mirror 11 can be realized by a flat optical element, and the thickness of the first semi-transmitting mirror 11 in the depth direction can be reduced.
  • the display device 1A can be made smaller in the depth direction.
  • the first semi-transmitting mirror 11 is a flat optical element, the distance between the first semi-transmitting mirror 11 and the display panel 2 can be reduced, or the first semi-transmitting mirror 11 and the display panel 2 can be brought into contact with each other, so that the display device 1A can be made smaller in the depth direction.
  • the first semi-transmitting mirror 11 including the HOE may have polarization selectivity.
  • the first semi-transmitting mirror 11 including the HOE may have a plurality of thin metal wires formed on the surface facing the display panel 2 or the surface facing the first retardation plate 12 to realize polarization selectivity that transmits S-wave polarized light and reflects P-wave polarized light. In this case, the decrease in brightness of the virtual image V viewed by the user 22 can be reduced.
  • the semi-transmitting mirror 6 of the display device 1 may be configured to include a HOE.
  • the optical function of the semi-transmitting mirror 6 can be realized by a flat optical element, and the thickness of the semi-transmitting mirror 6 in the depth direction can be reduced.
  • the display device 1 can be made smaller in the depth direction.
  • the semi-transmitting mirror 6 is a flat optical element, the distance between the semi-transmitting mirror 6 and the first retardation plate 5 can be reduced, or the semi-transmitting mirror 6 and the first retardation plate 5 can be brought into contact with each other, making it possible to further reduce the size of the display device 1 in the depth direction.
  • the first semi-transmitting mirror 17 of the display device 1B may be configured to include an HOE.
  • the optical function of the first semi-transmitting mirror 17 can be realized by a flat optical element, and the thickness of the first semi-transmitting mirror 17 in the depth direction can be reduced. As a result, the display device 1B can be made smaller in the depth direction.
  • the first semi-transmitting mirror 17 is a flat optical element, the distance between the first semi-transmitting mirror 17 and the display panel 2 can be reduced, or the first semi-transmitting mirror 17 and the display panel 2 can be brought into contact with each other, so that the display device 1B can be made smaller in the depth direction.
  • the first semi-transmitting mirror 17 including the HOE may have polarization selectivity.
  • the first semi-transmitting mirror 17 including the HOE may have a plurality of thin metal wires formed on the surface facing the display panel 2 or the surface facing the first retardation plate 18 to realize polarization selectivity that transmits S-wave polarized light and reflects P-wave polarized light. In this case, the decrease in brightness of the virtual image V viewed by the user 22 can be reduced.
  • the third semi-transmitting mirror 21 of the display device 1B may be configured to include an HOE.
  • the optical function of the third semi-transmitting mirror 21 can be realized by a flat optical element, and the thickness of the third semi-transmitting mirror 21 in the depth direction can be reduced. As a result, it is possible to reduce the size of the display device 1B in the depth direction.
  • the third semi-transmitting mirror 21 including the HOE may have polarization selectivity.
  • the third semi-transmitting mirror 21 including the HOE may have a plurality of thin metal wires formed on the surface facing the second retardation plate 20 or the surface opposite to the surface facing the second retardation plate 20, which realizes polarization selectivity that reflects S-wave polarized light and transmits P-wave polarized light.
  • the holographic optical element may, for example, have a pattern of interference fringes and be configured to diffract incident light in a predetermined direction.
  • the display device 1A' may be configured such that the second semi-transmitting mirror 13' includes a Fresnel lens.
  • the optical function of the second semi-transmitting mirror 13' can be realized by a substantially flat optical element having a reduced thickness (dimension in the depth direction) compared to a convex half mirror, and the thickness of the second semi-transmitting mirror 13' in the depth direction can be reduced. As a result, the display device 1A' can be made smaller in the depth direction.
  • the second semi-transmitting mirror 13' is substantially flat, the distance between the second semi-transmitting mirror 13' and the second retardation plate 14 can be reduced, or the second semi-transmitting mirror 13' and the second retardation plate 14 can be brought into contact with each other, so that the display device 1A' can be made smaller in the depth direction.
  • the second semi-transmitting mirror 13' including a Fresnel lens is also called a Fresnel half mirror 13'.
  • the Fresnel half mirror 13' may be configured to include a Fresnel lens (Fresnel convex lens) 33 having a planar first surface 33a facing the second retardation film 14 and a Fresnel-shaped second surface 33b facing the first retardation film 12, and a semi-transmissive reflective layer 34 located on the second surface 33b.
  • the Fresnel shape has concentric grooves centered on a reference point 33c.
  • the groove includes a surface that is approximately perpendicular to the first surface 33a and an inclined surface inclined with respect to the first surface 33a.
  • the inclined surface may be a curved surface or a flat surface.
  • the semi-transmissive reflective layer 34 may be located on the inclined surface of the Fresnel shape.
  • the semi-transmissive reflective layer 34 may transmit a portion (e.g., approximately 50%) of the incident light and reflect the remaining portion (e.g., approximately 50%).
  • the semi-transmissive reflective layer 34 may be a metal thin film.
  • the metal thin film may be made of a metal material such as aluminum or chromium.
  • the metal thin film may be formed by a deposition method such as CVD (Chemical Vapor Deposition) or PVD (Physical Vapor Deposition).
  • the Fresnel half mirror 13' has the optical function of a lens and the optical function of a half mirror.
  • the optical function of the lens e.g., focal length, etc.
  • the optical function of the half mirror is determined by the curvature and inclination angle of the inclined surface, the refractive index of the material that constitutes the Fresnel lens 33, etc.
  • the optical function of the half mirror e.g., focal length, transmittance, etc.
  • the curvature and inclination angle of the inclined surface e.g., focal length, transmittance, etc.
  • the Fresnel half mirror 13' may have a surface facing the second retardation plate 14 flattened by a transparent material layer formed on the second surface 33b of the Fresnel lens 33.
  • the transparent material layer may be made of a material having substantially the same refractive index as the material constituting the Fresnel lens 33.
  • the transparent material layer may be made of the same material as the material constituting the Fresnel lens 33.
  • the display device 1A' may be configured such that the first semi-transmitting mirror 11 includes a Fresnel lens.
  • the thickness of the first semi-transmitting mirror 11 can be reduced, and as a result, the display device 1A' can be made smaller in size in the depth direction.
  • the first semi-transmitting mirror 11 including the Fresnel lens is substantially flat, the distance between the first semi-transmitting mirror 11 and the display panel 2 can be reduced, or the first semi-transmitting mirror 11 and the display panel 2 can be brought into contact with each other, so that the display device 1A' can be made smaller in size in the depth direction.
  • the first semi-transmitting mirror 11 including a Fresnel lens is also called a Fresnel half mirror 11.
  • the Fresnel half mirror 11 may have a configuration similar to that of the Fresnel half mirror 13'.
  • the Fresnel half mirror 11 may be configured to include a Fresnel concave lens.
  • the Fresnel half mirror 11 may be configured to have polarization selectivity.
  • the Fresnel half mirror 11 may have a plurality of metal fine wires (metal nanowire grid) formed on the surface facing the display panel 2 or the surface facing the first retardation plate 12, which realizes polarization selectivity that transmits S-wave polarized light and reflects P-wave polarized light. This makes it possible to reduce the decrease in brightness of the virtual image V viewed by the user 22.
  • the first semi-transmitting mirror 11 of the display device 1A may be configured to include a Fresnel lens, as shown in FIG. 23.
  • the thickness of the first semi-transmitting mirror 11 can be reduced, and as a result, the display device 1A can be made smaller in size in the depth direction.
  • the first semi-transmitting mirror 11 including the Fresnel lens is substantially flat, the distance between the first semi-transmitting mirror 11 and the display panel 2 can be reduced, or the first semi-transmitting mirror 11 and the display panel 2 can be brought into contact with each other, so that the display device 1A can be made smaller in size in the depth direction.
  • the first semi-transmitting mirror 11 including the Fresnel lens may be configured to have polarization selectivity.
  • the first semi-transmitting mirror 11 including the Fresnel lens may have a plurality of thin metal wires formed on the surface facing the display panel 2 or the surface facing the first retardation plate 12, which realizes polarization selectivity that transmits S-wave polarized light and reflects P-wave polarized light. In this case, the decrease in brightness of the virtual image V viewed by the user 22 can be reduced.
  • the semi-transmitting mirror 6 of the display device 1 may be configured to include a Fresnel lens.
  • the thickness of the semi-transmitting mirror 6 can be reduced, and as a result, the display device 1 can be made smaller in size in the depth direction.
  • the semi-transmitting mirror 6 including the Fresnel lens is substantially flat, the distance between the semi-transmitting mirror 6 and the first retardation film 5 can be reduced, or the semi-transmitting mirror 6 and the first retardation film 5 can be brought into contact with each other, making it possible to further reduce the size of the display device 1 in the depth direction.
  • the first semi-transmitting mirror 17 of the display device 1B may be configured to include a Fresnel lens.
  • the thickness of the first semi-transmitting mirror 17 can be reduced, and as a result, the display device 1B can be made smaller in size in the depth direction.
  • the first semi-transmitting mirror 17 including the Fresnel lens is substantially flat, the distance between the first semi-transmitting mirror 17 and the display panel 2 can be reduced, or the first semi-transmitting mirror 17 and the display panel 2 can be brought into contact with each other, so that the display device 1B can be made smaller in size in the depth direction.
  • the first semi-transmitting mirror 17 including the Fresnel lens may be configured to have polarization selectivity.
  • the first semi-transmitting mirror 17 including the Fresnel lens may have a plurality of thin metal wires formed on the surface facing the display panel 2 or the surface facing the first retardation plate 18, which realizes polarization selectivity that transmits S-wave polarized light and reflects P-wave polarized light.
  • the decrease in brightness of the virtual image V viewed by the user 22 can be reduced.
  • the third semi-transmitting mirror 21 of the display device 1B may be configured to include a Fresnel lens. In this case, the thickness of the third semi-transmitting mirror 21 can be reduced, and as a result, the display device 1B can be made smaller in size in the depth direction.
  • the third semi-transmitting mirror 21 including the Fresnel lens may be configured to have polarization selectivity.
  • the third semi-transmitting mirror 21 including the Fresnel lens may have a plurality of thin metal wires formed on the surface facing the second retardation plate 20 or the surface opposite to the surface facing the second retardation plate 20, which realizes polarization selectivity that reflects S-wave polarized light and transmits P-wave polarized light. In this case, it is possible to reduce the deterioration in quality of the virtual image V viewed by the user 22, and also to reduce the deterioration in brightness of the virtual image V.
  • the imaging device 100 is a digital rearview mirror (see FIG. 10).
  • the imaging device 100 is equipped with an angle sensor that detects the orientation of the display device 1, 1A, 1A', 1B relative to a predetermined direction fixed to the moving body 23.
  • the predetermined direction may be, for example, the vehicle length direction of the moving body 23, but is not limited to this.
  • the angle sensor may be a three-axis angle sensor that can detect the orientation (roll, pitch, yaw) of the display device 1, 1A, 1A', 1B.
  • the moving body 23 is equipped with a DMS (Driver Monitoring System), and the imaging device 100 is capable of communicating with the DMS and controlling the DMS.
  • the DMS is capable of capturing an image of the face of a user 22 seated in the driver's seat of the moving body 23, performing face authentication of the user 22, and determining whether the user 22 is a known user.
  • a known user may refer to a user whose information (also called user information) such as features used for face recognition, eye position while driving, and face direction is stored in the memory unit of the controller 43 and/or the memory unit of the DMS.
  • the size of left viewing area PL and the size of right viewing area PR are approximately the same (see FIG. 25), and user 22 can see virtual image V, which changes in response to head movement, just as when using a normal rearview mirror.
  • the size of left viewing area PL and the size of right viewing area PR do not match (see FIG. 26), and user 22 cannot see virtual image V, which changes in response to head movement, just as when using a normal rearview mirror, and may feel uncomfortable.
  • the flowchart in FIG. 29 begins, for example, when a user 22 sits in the driver's seat of a vehicle 23 and starts the engine of the vehicle 23.
  • the DMS is controlled to confirm (user confirmation) the user 22 seated in the driver's seat of the vehicle 23.
  • [S2] face authentication is performed on the user 22 seated in the driver's seat, and the DMS is controlled to determine whether or not the user 22 is a known user. If in [S2] the user 22 is a known user [Yes], the process proceeds to [S3]. If in [S2] the user 22 is not a known user [No], the process proceeds to [S7].
  • user information of user 22 (such as eye position and face direction while driving) is obtained from the DMS.
  • the display devices 1, 1A, 1A', 1B are adjusted based on the user information acquired in [S3].
  • the adjustment of the display devices 1, 1A, 1A', 1B may include changing the display area of the display image on the display surface 2a of the display panel 2 according to the orientation of the display devices 1, 1A, 1A', 1B, the eye position of the user 22, the face orientation, etc. Changing the display area may be to make a part of the display surface 2a a non-display area 2b that does not display an image, as shown in FIG. 27. As shown in FIG.
  • the size of the left peek area PL and the size of the right peek area PR can be made approximately equal, even if the user 22 is not located directly in front of the display devices 1, 1A, 1A', 1B, and as a result, the risk of the user 22 feeling uncomfortable can be reduced.
  • Adjustment of the display devices 1, 1A, 1A', 1B may include sliding (translating) at least one of the reflective polarizer 8, semi-transparent mirror 6, and display panel 2 in a direction perpendicular to the emission direction of the display light from the display panel 2, depending on the orientation of the display devices 1, 1A, 1A', 1B, the eye position of the user 22, the face orientation, etc.
  • the size of the left viewing area PL and the size of the right viewing area PR can be made to be approximately the same as shown in FIG. 28, and as a result, the risk of the user 22 feeling uncomfortable can be reduced.
  • the size of the left viewing area PL and the right viewing area PR can be reduced from being smaller than when the user 22 is positioned directly in front of the display devices 1, 1A, 1A', 1B.
  • the controller 43 receives an instruction from the user 22 as to whether or not readjustment of the display devices 1, 1A, 1A', 1B is necessary.
  • the imaging device 100 may be configured so that the user 22 can indicate that readjustment is necessary by operating a button or the like provided on the steering wheel.
  • the imaging device 100 may be configured so that the user 22 can indicate that readjustment is necessary by swinging the imaging device 100 and varying the orientation of the imaging device 100.
  • the variation in the orientation of the imaging device 100 may be detected by a three-axis angle sensor of the imaging device 100.
  • the controller 43 may determine that readjustment is not necessary if there is no instruction from the user 22 within a predetermined time from when the controller 43 starts accepting instructions from the user 22.
  • the predetermined time may be, for example, about 3 to 10 seconds, but is not limited to this.
  • the controller 43 controls the DMS to detect user information of the user 22 (information such as the eye position and face direction while driving) and acquires the user information of the user 22 from the DMS.
  • the display devices 1, 1A, 1A', and 1B are adjusted based on the user information acquired in [S6].
  • the adjustment of the display devices 1, 1A, 1A', and 1B may be similar to the adjustment of the display devices 1, 1A, 1A', and 1B in [S4].
  • the controller 43 stores the user information of the user 22 and information related to the adjustment of the display devices 1, 1A, 1A', and 1B in the memory unit of the controller 43 and/or the memory unit of the DMS, and ends this flowchart.
  • the viewing area in the digital rearview mirror can be efficiently controlled, and the risk of the user 22 feeling uncomfortable can be reduced.
  • the flowchart in FIG. 29 can also be applied when the imaging device 100 constitutes a digital side mirror.
  • the display device 1C of this example includes a display panel 2, an optical system 35, and a housing 36.
  • the display panel 2 has a display surface 2a, and displays a display image on the display surface 2a.
  • the optical system 35 projects the display light emitted from the display panel 2 into the field of view of the user 22 as a virtual image V.
  • the optical system 35 may be the optical system 3 (see Figures 2, 3, 30), the optical system 10 (see Figures 4, 5, 31), or the optical system 16 (see Figures 9, 32).
  • Figures 33 to 36 show the case where the optical system 35 is the optical system 3 shown in Figure 30.
  • the housing 36 houses the display panel 2 and the optical system 35.
  • the housing 36 may hold the display panel 2 and the optical system 35.
  • the housing 36 may house and hold the illuminator 4.
  • the housing 36 has a window (opening) 37 that transmits the light emitted from the optical system 35.
  • the display device 1C may be arranged so that the window 37 and the display panel 2 overlap when the window 37 of the housing 36 is viewed.
  • the display device 1C may be arranged so that the window 37 and the optical system 35 overlap when the window 37 of the housing 36 is viewed.
  • the display device 1C may be arranged so that the display panel 2 and the optical system 35 overlap when the window 37 of the housing 36 is viewed.
  • the space occupied by the display device 1C can be reduced, and as a result, the display device 1C can be made smaller.
  • the display light emitted from the display panel 2 propagates substantially on one axis and is formed as a virtual image V. This reduces distortion and uneven brightness of the virtual image V viewed by the user 22, and also makes it easier to design the optical system 35.
  • the housing 36 may have a light-transmitting plate 38 arranged in the window 37, as shown in Figs. 33 and 34.
  • the light-transmitting plate 38 may transmit light emitted from the optical system 35.
  • the light-transmitting plate 38 at least partially covers the window 37.
  • the light-transmitting plate 38 may be made of, for example, glass, resin, etc.
  • the optical system 35 may have a third retardation plate 25 and a fourth retardation plate 26.
  • the third retardation plate 25 may be located on the surface of the second retardation plate 7 facing the semi-transmitting mirror 6.
  • the fourth retardation plate 26 may be located on the surface of the third retardation plate 25 facing the semi-transmitting mirror 6. This allows the relative angle between the transmission axis of the front polarizer of the display panel 2 and the transmission axis of the reflective polarizer 8 to approach a crossed Nicol arrangement even when the user 22 is not located in front of the display device 1C, thereby reducing the deterioration of the display quality of the display device 1C.
  • the third retardation plate 25 and the fourth retardation plate 26 may be, but are not limited to, a 1/2 wave plate (half wave plate).
  • the third retardation plate 25 and the fourth retardation plate 26 may be a 1/4 wave plate, a 1/8 wave plate, a 1/16 wave plate, etc., or may be a wave plate that imparts other phase differences.
  • the third retardation plate 25 and the fourth retardation plate 26 may be wave plates that impart the same phase difference, or may be wave plates that impart different phase differences.
  • the optical axis of the third retardation plate 25 may be approximately parallel or approximately perpendicular to the transmission axis of the reflective polarizer 8.
  • the optical system 35 may have a moth-eye structure film 39 located on the surface of the first retardation plate 5 facing the semi-transmitting mirror 6.
  • the moth-eye structure film 39 can attenuate the reflected light of the light incident from the semi-transmitting mirror 6 side. This can reduce unwanted light and ambient light, etc., being reflected by the first retardation plate 5, being emitted from the display device 1C, and being incident on the eyes of the user 22.
  • the optical system 35 may have a moth-eye structure film 40 located on the surface of the fourth retardation plate 26 facing the semi-transmissive mirror 6. This reduces the amount of unnecessary light and ambient light, etc., that is reflected by the fourth retardation plate 26, emitted from the display device 1C, and incident on the eyes of the user 22.
  • the reflective polarizer 8, the second retardation plate 7, the third retardation plate 25, the fourth retardation plate 26, the moth-eye structure film 40, and the light-transmitting plate 38 may be integrated together. This allows the display device 1C to be made thinner in the depth direction (Z-axis direction). In addition, deformation of the reflective polarizer 8, the second retardation plate 7, the third retardation plate 25, the fourth retardation plate 26, the moth-eye structure film 40, and the light-transmitting plate 38 can be reduced.
  • the display device 1C may have a touch panel 41.
  • the touch panel 41 may at least partially cover the window 37.
  • the touch panel 41 may be attached to the housing 36 as shown in Figs. 35 and 36.
  • the touch panel 41 may be attached to the housing 36 so as to cover the window 37 in which the light-transmitting plate 38 is arranged as shown in Figs. 35 and 36.
  • the touch panel 41 may cover the light-transmitting plate 38.
  • the touch panel 41 is communicatively connected to the controller 43 via a wired or wireless communication line. This allows the user 22 to operate the display device 1C via the touch panel 41.
  • the touch panel 41 may be a known touch panel.
  • the display system 200 includes display devices 1, 1A, 1A', 1B, and 1C, and a camera 201.
  • the display panel 2 of the display devices 1, 1A, 1A', 1B, and 1C is capable of communicating with the camera 201, and displays an image captured by the camera 201.
  • the display panel 2 and the camera 201 may be connected, for example, via a wired connection, wireless connection, or CAN (Controller Area Network), etc.
  • the moving body (vehicle) 23 of the present disclosure includes a display system 200.
  • the display devices 1, 1A, 1A', 1B, and 1C are small display devices that do not occupy a large volume in the cab of the vehicle 23 even when placed therein, and are unlikely to interfere with driving. Therefore, the user 22 can properly view the virtual image V or real image.
  • the display system 200 may be applied to the digital rearview mirror of the vehicle 23, or to the digital side mirrors 1L and 1R (see FIG. 12).
  • the display system 200 may be applied to the cluster 29, CID (Center Information Display) 30, PID (Passenger Information Display) 31, RSE (Rear Seat Entertainment) system 32, etc. (see FIGS. 10 and 12) in the dashboard of the vehicle 23.
  • the present disclosure it is possible to reduce the degradation of display quality in a small display device and improve the light utilization efficiency. Furthermore, according to the present disclosure, it is possible to provide a small imaging device that allows the user to clearly view a virtual image.
  • the display device of the present disclosure can be implemented in the following aspects (1) to (48).
  • a display panel that emits linearly polarized display light; a first retardation plate facing the display panel; a second retardation plate disposed apart from the first retardation plate; a reflective polarizing plate that transmits polarized light having a polarization axis parallel to the polarization axis of the display light and reflects polarized light having a polarization axis perpendicular to the polarization axis of the display light; a semi-transmitting mirror disposed between the first retardation plate and the second retardation plate and having a reflecting surface facing the second retardation plate,
  • the display device wherein the first retardation plate and the second retardation plate are quarter-wave plates.
  • a display device according to any one of (1) to (6) above, in which the reflective surface of the semi-transparent mirror is concave.
  • a display device in which the semi-transparent mirror is a flat optical element made of a holographic optical element.
  • a display panel that emits linearly polarized display light; a first retardation plate facing the display panel; a second retardation plate disposed apart from the first retardation plate; a first semi-transmitting mirror disposed between the display panel and the first retardation plate and having a first reflecting surface facing the first retardation plate; a second semi-transparent mirror disposed between the first retardation plate and the second retardation plate and having a second reflecting surface facing the first retardation plate; a polarizing plate facing the second retardation plate,
  • the display device wherein the first retardation plate and the second retardation plate are quarter-wave plates.
  • a display device in which the first retardation plate and the second retardation plate convert the display light into a first polarized light that transmits through the polarizing plate and a second polarized light that transmits less through the polarizing plate than the first polarized light.
  • a display device according to any one of (11) to (17) above, in which the first semi-transparent mirror and the second semi-transparent mirror are flat optical elements made of holographic optical elements.
  • a display panel that emits linearly polarized display light; a first retardation plate facing the display panel; a second retardation plate disposed apart from the first retardation plate; a first semi-transmitting mirror disposed between the display panel and the first retardation plate and having a first reflecting surface facing the first retardation plate; a second semi-transmitting mirror disposed between the first retardation plate and the second retardation plate and having a second reflecting surface facing the first retardation plate and a third reflecting surface facing the second retardation plate; a third semi-transparent mirror having a fourth reflecting surface facing the second retardation plate,
  • the display device wherein the first retardation plate and the second retardation plate are quarter-wave plates.
  • a display panel that emits display light; a first retardation plate that transmits the display light; a second retardation plate disposed apart from the first retardation plate; a first semi-transmitting mirror disposed between the display panel and the first retardation plate and having a first reflecting surface facing the first retardation plate; a second semi-transparent mirror disposed between the first phase difference plate and the second phase difference plate, the second semi-transparent mirror having a second reflecting surface facing the first phase difference plate and a third reflecting surface facing the second phase difference plate; a third semi-transparent mirror having a fourth reflecting surface facing the second retardation plate.
  • the display light includes a display light for a left eye image and a display light for a right eye image
  • the display device according to any one of (1) to (29) above, further comprising an optical element that defines the direction of each of the light rays of the display light for the left eye image and the display light for the right eye image.
  • An imaging device including a display device according to any one of (1) to (30) above.
  • the virtual image projected within the user's field of vision includes a binocular visible area that is visible with both the left and right eyes of the user, a left eye visible area that is visible only with the left eye, and a right eye visible area that is visible only with the right eye.
  • a display panel (33) a display panel; and an optical system that projects a display light emitted from the display panel as a virtual image or a real image; a housing that houses the display panel and the optical system, the housing has a window through which light emitted from the optical system passes, A display device, wherein the window of the housing is arranged so that the window, the optical system, and the display panel overlap when the window is viewed from the front.
  • a display device according to any one of (1) to (30) and (33) to (35) above, comprising an illuminator that irradiates light onto the surface of the display panel opposite the display surface.
  • a display device according to any one of (1) to (30) and (33) to (36) above, comprising a controller having a function of controlling at least one of the image to be displayed on the display panel and the irradiator.
  • a display panel that emits linearly polarized display light; a first retardation plate facing the display panel; a second retardation plate disposed apart from the first retardation plate; a reflective polarizing plate that transmits polarized light having a polarization axis parallel to the polarization axis of the display light and reflects polarized light having a polarization axis perpendicular to the polarization axis of the display light; a semi-transmitting mirror disposed between the first retardation plate and the second retardation plate and having a reflecting surface facing the second retardation plate; the first retardation plate and the second retardation plate are quarter-wave plates, a light path length of light emitted from the display panel, transmitted through the semi-transmitting mirror, reflected by the reflective polarizing plate, and reaching the semi-transmitting mirror is shorter than a focal length of the semi-transmitting mirror.
  • a display panel that emits linearly polarized display light; a first retardation plate facing the display panel; a second retardation plate disposed apart from the first retardation plate; a reflective polarizing plate that transmits polarized light having a polarization axis parallel to the polarization axis of the display light and reflects polarized light having a polarization axis perpendicular to the polarization axis of the display light; a semi-transmitting mirror disposed between the first retardation plate and the second retardation plate and having a reflecting surface facing the second retardation plate; the first retardation plate and the second retardation plate are quarter-wave plates, a light path length of light emitted from the display panel, transmitted through the semi-transmitting mirror, reflected by the reflective polarizing plate, and reaching the semi-transmitting mirror is longer than a focal length of the semi-transmitting mirror.
  • a display panel that emits linearly polarized display light; a first retardation plate that transmits the display light; a second retardation plate disposed apart from the first retardation plate; a first semi-transmitting mirror disposed between the display panel and the first retardation plate and having a first reflecting surface facing the first retardation plate; a second semi-transparent mirror disposed between the first retardation plate and the second retardation plate and having a second reflecting surface facing the first retardation plate; a polarizing plate facing the second retardation plate, the first retardation plate and the second retardation plate are quarter-wave plates, a light path length of light emitted from the display panel, transmitted through the first semi-transparent mirror, reflected by the second semi-transparent mirror, and reaching the first semi-transparent mirror is shorter than a focal length of the first semi-transparent mirror.
  • a display panel that emits linearly polarized display light; a first retardation plate that transmits the display light; a second retardation plate disposed apart from the first retardation plate; a first semi-transmitting mirror disposed between the display panel and the first retardation plate and having a first reflecting surface facing the first retardation plate; a second semi-transparent mirror disposed between the first retardation plate and the second retardation plate and having a second reflecting surface facing the first retardation plate; a polarizing plate facing the second retardation plate, the first retardation plate and the second retardation plate are quarter-wave plates, a light path length of light emitted from the display panel, transmitted through the first semi-transparent mirror, reflected by the second semi-transparent mirror, and reaching the first semi-transparent mirror is longer than a focal length of the first semi-transparent mirror.
  • a display panel that emits linearly polarized display light; a first retardation plate that transmits the display light; a second retardation plate disposed apart from the first retardation plate; a first semi-transmitting mirror disposed between the display panel and the first retardation plate and having a first reflecting surface facing the first retardation plate; a second semi-transparent mirror disposed between the first phase difference plate and the second phase difference plate, the second semi-transparent mirror having a second reflecting surface facing the first phase difference plate and a third reflecting surface facing the second phase difference plate; a third semi-transparent mirror having a fourth reflecting surface facing the second retardation plate, the first retardation plate and the second retardation plate are quarter-wave plates, a display device, wherein an optical path length of light that is emitted from the display panel, passes through the first semi-transparent mirror, is reflected by the second semi-transparent mirror, and reaches the first semi-transparent mirror is shorter than a focal length of the first semi-transparent mirror, and wherein an optical path length of light that is
  • a display panel that emits linearly polarized display light; a first retardation plate that transmits the display light; a second retardation plate disposed apart from the first retardation plate; a first semi-transmitting mirror disposed between the display panel and the first retardation plate and having a first reflecting surface facing the first retardation plate; a second semi-transparent mirror disposed between the first phase difference plate and the second phase difference plate, the second semi-transparent mirror having a second reflecting surface facing the first phase difference plate and a third reflecting surface facing the second phase difference plate; a third semi-transparent mirror having a fourth reflecting surface facing the second retardation plate, the first retardation plate and the second retardation plate are quarter-wave plates, a display device, wherein an optical path length of light that is emitted from the display panel, passes through the first semi-transparent mirror, is reflected by the second semi-transparent mirror, and reaches the first semi-transparent mirror is longer than a focal length of the first semi-transparent mirror, and wherein an optical path length of light that is
  • a display panel that emits display light; a convex lens through which the display light passes, The display device, wherein an optical path length from the display panel to the convex lens is shorter than a focal length of the convex lens.
  • a display panel that emits display light; a convex lens through which the display light passes, A display device, wherein an optical path length from the display panel to the convex lens is longer than a focal length of the convex lens.
  • a display device according to any one of (1) to (30), (33) to (37), and (39) to (46) above; A camera;
  • the display panel is capable of communicating with the camera and displays an image captured by the camera.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Engineering & Computer Science (AREA)
  • Transportation (AREA)
  • Combustion & Propulsion (AREA)
  • Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Devices For Indicating Variable Information By Combining Individual Elements (AREA)
  • Polarising Elements (AREA)
  • Electroluminescent Light Sources (AREA)
  • Lenses (AREA)
  • Fittings On The Vehicle Exterior For Carrying Loads, And Devices For Holding Or Mounting Articles (AREA)
  • Instrument Panels (AREA)
PCT/JP2024/040045 2023-11-10 2024-11-11 表示装置、結像装置、表示システムおよび車両 Pending WO2025100550A1 (ja)

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KR1020257031744A KR20250151535A (ko) 2023-11-10 2024-11-11 표시 장치, 결상 장치, 표시 시스템 및 차량
CN202480004796.XA CN120303608A (zh) 2023-11-10 2024-11-11 显示装置、成像装置、显示系统、以及车辆
JP2024568414A JP7725744B1 (ja) 2023-11-10 2024-11-11 表示装置、結像装置、表示システムおよび車両
EP24883535.7A EP4603892A4 (en) 2023-11-10 2024-11-11 DISPLAY DEVICE, IMAGE FORMING DEVICE, DISPLAY SYSTEM AND VEHICLE
KR1020267002991A KR20260023602A (ko) 2024-05-10 2025-05-09 표시 장치, 표시 시스템, 차량 및 표시 패널 수용 장치
JP2025534708A JP7747936B1 (ja) 2024-05-10 2025-05-09 表示装置、表示システム、車両及び表示パネル収容装置
PCT/JP2025/017146 WO2025234496A1 (ja) 2024-05-10 2025-05-09 表示装置、表示システム、車両及び表示パネル収容装置
CN202580003943.6A CN121646726A (zh) 2024-05-10 2025-05-09 显示装置、显示系统、车辆、以及显示面板收容装置
US19/209,490 US20250277982A1 (en) 2023-11-10 2025-05-15 Display device, imaging device, display system, and vehicle
JP2025128981A JP2025172065A (ja) 2024-05-10 2025-07-31 表示装置、表示システム、車両及び表示パネル収容装置
JP2025130909A JP2025169300A (ja) 2023-11-10 2025-08-05 表示装置、結像装置、表示システムおよび車両
JP2025244897A JP7826561B1 (ja) 2024-05-10 2025-12-10 表示装置、表示システム、移動体及び表示パネル収容装置
JP2025244900A JP2026065646A (ja) 2024-05-10 2025-12-10 表示装置、移動体、表示システム及び表示パネル収容装置
JP2025244896A JP7842938B1 (ja) 2024-05-10 2025-12-10 表示装置、移動体、表示システム及び表示パネル収容装置

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