WO2022168398A1 - Dispositif de visiocasque - Google Patents

Dispositif de visiocasque Download PDF

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Publication number
WO2022168398A1
WO2022168398A1 PCT/JP2021/042311 JP2021042311W WO2022168398A1 WO 2022168398 A1 WO2022168398 A1 WO 2022168398A1 JP 2021042311 W JP2021042311 W JP 2021042311W WO 2022168398 A1 WO2022168398 A1 WO 2022168398A1
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WO
WIPO (PCT)
Prior art keywords
display device
light
lcos
image display
head
Prior art date
Application number
PCT/JP2021/042311
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English (en)
Japanese (ja)
Inventor
雅孝 杉田
Original Assignee
株式会社日立エルジーデータストレージ
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Publication of WO2022168398A1 publication Critical patent/WO2022168398A1/fr

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    • 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
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/13363—Birefringent elements, e.g. for optical compensation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/64—Constructional details of receivers, e.g. cabinets or dust covers

Definitions

  • the present invention relates to a head-mounted display device (HMD: Head Mount Display, hereinafter referred to as HMD) that projects and displays a virtual image.
  • HMD Head Mount Display
  • An HMD is a device that generates a virtual image and displays an image through glasses-like or goggle-like light guide elements.
  • liquid crystal on silicon for example, is known as a video display device that modulates light incident from an illumination system based on a video signal to generate an image.
  • LCOS has a liquid crystal between the pixel electrode for image generation and the common electrode, and by controlling the electric field between the electrodes for each pixel based on the image signal, the polarization corresponding to the change in the phase difference of the light that has passed through the liquid crystal It displays images by generating brightness and darkness depending on the angle. Due to the variation in the polarization angle, contrast (luminance ratio of all white/all black) deteriorates.
  • Patent Document 1 discloses a first image forming apparatus, a first polarizing beam splitter through which illumination light passes to reach the first image forming apparatus, the first image forming apparatus, and a first polarized beam splitter. a first retardation element interposed between the beam splitter and attached to the first imaging device for substantially enhancing contrast in image light passing through the first polarizing beam splitter from the first imaging device; and a bias controller for biasing the pixels in the dark state to maximize the intensity.
  • An object of the present invention is to provide an HMD that can adjust and improve contrast deterioration with a simple configuration.
  • the present invention provides an image display device having a liquid crystal layer that changes the polarization angle between 90° and 0°, and an illumination system that supplies illumination light to the image display device. and a polarization optical element that guides irradiation light to the image display device and selects transmission/reflection according to the polarization angle of the light that varies depending on the image display device, wherein the polarization optical element and the image display device and the polarization function element is arranged between them.
  • FIG. 1 is a schematic configuration diagram of an image display unit in a conventional HMD;
  • FIG. It is a figure explaining the structure of the conventional LCOS. It is a figure explaining the operation
  • FIG. 10 is a diagram for explaining the operation of the LCOS and the PBS when the conventional video signal is all black; It is a figure explaining the subject in the case of the conventional HMD for one eye. It is a figure explaining the subject in the case of the conventional HMD for one eye. It is a figure explaining the subject in the case of the conventional HMD for one eye. It is a figure explaining the subject in the case of the conventional HMD for one eye. It is a figure explaining the subject in the case of the conventional HMD for one eye. It is a figure explaining the subject in the case of the conventional HMD for one eye. It is a figure explaining the subject in the case of the conventional HMD for one eye.
  • FIG. 1 is a schematic configuration diagram of a reflective image display unit using LCOS in Example 1.
  • FIG. 1 is a schematic configuration diagram of a transmissive image display unit using an LCD in Example 1.
  • FIG. 5 is a processing flowchart of contrast adjustment in Embodiment 1.
  • FIG. 10 is a simulation result of contrast with respect to polarization angle variation of LCOS without rotational adjustment in Example 1.
  • FIG. FIG. 10 is a simulation result of contrast with respect to polarization angle variation of LCOS with rotation adjustment in Example 1.
  • FIG. FIG. 10 is a diagram illustrating the configuration of a video display device according to Example 2;
  • FIG. 1 is a schematic configuration diagram of a video display unit in a conventional HMD. Note that if one structure of FIG. 1 is provided, it becomes a monocular HMD, and if it is provided with two structures, it becomes a binocular HMD.
  • an image display unit 100 includes an illumination system 10, a polarizing optical element PBS (Polarizing Beam Splitter) 20, an image display device 30, a projection system 40, and a light guide unit 50. ing.
  • PBS Polarizing Beam Splitter
  • the illumination system 10 has a light source 11 and a light source 13 which are light source units, condenser lenses 12 and 14, a dichroic mirror 15, a microlens array 16, a total reflection mirror 17, and an imaging lens . Note that some components may be omitted from the illumination system 10 as long as the image display device 30 can be illuminated via the PBS 20 .
  • the light source 11 in the light source unit emits green light (G light)
  • the light source 13 includes a red light source and a blue light source mounted in the same package, and emits red light and blue light (R light). and B light).
  • FIG. 1 shows the light source 13 in which two color light sources are mounted in the same package as an example, but each of the three color light sources may be mounted in an independent package. Colored light sources may be integrated and implemented in one package.
  • the light emitted from the light source 11 enters the condensing lens 12 .
  • the condensing lens 12 is arranged so that the light source 11 is positioned substantially at its synthetic focal position.
  • a light beam emitted from the light source 11 enters the condenser lens 12 and becomes collimated light. Collimated light from light source 11 is emitted toward dichroic mirror 15 .
  • the light emitted from the light source 13 enters the condensing lens 14 to become collimated light and is emitted toward the dichroic mirror 15 .
  • the dichroic mirror 15 aligns the optical axes of the R light, the B light, and the G light, synthesizes them, and synthesizes and emits the collimated light of each color.
  • the microlens array 16 receives substantially collimated light beams emitted from the dichroic mirror 15 .
  • the approximately collimated light is generated by the condensing lenses 12 and 14, and is a collimated light beam having a spread of light corresponding to the light emitting area of the light source section. Therefore, when the light is condensed by a lens provided on the incident side of the microlens array 16, an image of the light source is formed on the lens on the outgoing side of the microlens array 16.
  • FIG. A lens provided on the exit side of the microlens array emits a light beam having a light distribution corresponding to the aperture shape of the lens provided on the incidence side of the microlens array.
  • the light flux emitted from the microlens array 16 is totally reflected by the total reflection mirror 17, bends its course at a substantially right angle, and enters the imaging lens 18.
  • the imaging lens 18 emits the collimated light toward the PBS 20 while condensing it.
  • the PBS 20 is an optical material made of a transparent material and having an incident surface, a reflecting surface, and an exit surface.
  • the reflective surface is inclined with respect to the optical axis of the imaging lens 18 and has polarization-selective reflective performance. That is, S-polarized light is reflected, but P-polarized light is transmitted. Therefore, when the light flux from the imaging lens 18 is P-polarized light, the light flux from the imaging lens 18 is transmitted through the reflecting surface and illuminates the image display device 30 . Details will be described later.
  • the image display device 30 modulates the light incident from the illumination system 10 based on the image signal to generate an image.
  • the image light generated by the image display device 30 becomes image light and enters the projection system 40 via the PBS 20 .
  • the projection system 40 projects the image of the video display device 30 .
  • the projection system 40 provides the image of the video display device 30 as a virtual image in order to form the image of the video display device 30 on the retina so that it exists at a desired distance from the user. Therefore, the image light from the projection system 40 is emitted to the light guide section 50 .
  • the light guide unit 50 takes in the image light generated by the image display device 30 from the projection system 40, internally reflects it, and guides it to the front of the user.
  • FIG. 2 is a diagram for explaining the configuration of the video display device 30.
  • the image display device 30 is an LCOS, and is composed of a cover glass 31, a liquid crystal layer 32, and a display panel 33.
  • the LCOS has a liquid crystal layer 32 in front of the display panel 33, and the liquid crystal layer 32 electrically manipulates the polarized light and changes the polarization angle to adjust the color and control the contrast. That is, the display panel 33 reflects illumination light incident from the illumination system 10 .
  • the liquid crystal layer 32 modulates and manipulates the polarization of the illumination light incident from the illumination system 10 on the basis of the video signal, thereby controlling the emitted light. Accordingly, the image display device 30 modulates the light incident from the illumination system 10 based on the image signal to generate image light.
  • FIG. 3A and 3B are diagrams for explaining the operation of the video display device 30 and the PBS 20.
  • the image display device 30 is an LCOS
  • S-polarized light is defined as a vertical polarization direction
  • P-polarized light is defined as a horizontal polarization direction
  • FIG. 4 is a diagram for explaining that light emitted from the image display device 30 is incident on the projection system 40 via the PBS 20 when is all white.
  • FIG. 3A when the video signal is all white, the liquid crystal layer 32 rotates the polarization of the overall video signal by 90 degrees.
  • FIG. 3B is a diagram for explaining the relationship between the light emitted from the image display device 30 and the light incident on the projection system 40 when the image signal is completely black.
  • the liquid crystal layer 32 does not polarize the video signal in general. Therefore, when the luminous flux from the imaging lens 18 is P-polarized light, the emitted light from the image display device 30 is also P-polarized light, and is transmitted through the reflecting surface of the PBS 20 and does not enter the projection system 40 .
  • the polarization angle of the liquid crystal layer 32 of the LCOS in the image display device 30 varies from component to component, and the actual range of variation is about several degrees. Therefore, even if the video signal is completely black, if the polarization angle deviates from 90 degrees, a small amount of light will enter the projection system. Therefore, in that case, there is a problem that deterioration of contrast is caused.
  • the HMD attitude adjustment mechanism 80 is required.
  • FIG. 5 is a diagram for explaining problems in the case of a binocular HMD. As shown in FIG. 5, if the LCOS itself is adjusted by rotating in order to absorb the variation in the polarization angle of the LCOS for the left eye and the right eye, the image shifts between the two eyes. Therefore, it is necessary to adjust the rotation of the LCOS so that the images of both eyes match, and to adjust the contrast by another method.
  • FIG. 6 shows the reflectance simulation results of LCOS illumination light.
  • FIG. 6 shows the reflectance (absolute value) and reflection change rate (change rate) of the LCOS with respect to the polarization angle shift of the LCOS when the video signal is all white and all black. Note that the rate of change is defined as 100% when the deviation of the polarization angle is 0 degrees. As can be seen from the graph of the rate of change, the shift in the polarization angle of the LCOS slightly reduces the amount of light in full white, but the effect is large in the case of full black, which has a low reflectance. Therefore, it is all black that has a large effect on the contrast (all white/all black ratio).
  • CR overall contrast
  • CRp contrast of light reflected by the LCOS (all white/all black)
  • CP1 contrast of the LCOS part itself (this time: calculated by 250).
  • the contrast is adjusted so that the contrast becomes 200 or more with respect to the variation in the polarization angle of the LCOS, the variation in the polarization angle of the LCOS can be absorbed and the contrast performance can be stabilized. can.
  • FIG. 7 is a schematic configuration diagram of an image display unit for one eye and for both eyes in this embodiment.
  • the same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.
  • the difference from FIG. 1 is that a ⁇ /2 wavelength plate 35, which is a polarization function element, is added between the image display device 30 (LCOS) and the PBS 20, and the ⁇ /2 wavelength plate 35 is rotated. The point is that the contrast is adjusted.
  • LCOS image display device 30
  • FIG. 8 is a schematic configuration diagram when using a video display device 60 that is a transmissive LCD (Liquid Crystal Display).
  • the illumination system 10 and the imaging lens 18 are the same as those in FIG. 7 using LCOS, the total reflection mirror 17 is eliminated, and the line from the image display device 60 (LCD) to the light guide section 50 is made straight, and the image is displayed.
  • This is an example of an optical system in which the display unit 100 is made compact so as to fit on the frame of spectacles. Since the ⁇ /2 wavelength plate 35 is arranged between the image display device 60 (LCD) and the PBS 20, the contrast can be adjusted in the same manner as in FIG.
  • FIG. 9 is a processing flowchart of contrast adjustment in this embodiment.
  • the contrast adjustment is performed in the LCOS adjustment (focus, position, rotation) process of the HMD manufacturing process. That is, in FIG. 9, LCOS adjustment is started (S101), and conventional LCOS adjustment is completed (S102). Then, the contrast is checked (S103). For example, if the contrast is 200 or less, the ⁇ /2 wavelength plate is rotated to adjust the contrast (S104). Then, returning to S103, the ⁇ /2 wavelength plate is rotated to adjust the contrast until the contrast exceeds 200. When the contrast exceeds 200, the contrast adjustment is completed (S105).
  • FIGS. 10A and 10B are diagrams for explaining the effect of contrast adjustment in this embodiment, and are simulation results of contrast with respect to variations in polarization angle of LCOS.
  • FIG. 10A shows the case without rotation adjustment by the ⁇ /2 waveplate, and is similar to the contrast simulation result of FIG.
  • FIG. 10B shows a case where rotation adjustment is performed using a ⁇ /2 wavelength plate, and the contrast can be stabilized by absorbing variations in the polarization angle of the LCOS.
  • the video display device 30 (LCOS) or the video display device 60 (LCD) has been described, but the present invention is not limited to the LCOS or LCD. Any image display device made of a liquid crystal layer that changes the angle to 100° can be used.
  • the polarization function element is not limited to this, and may be, for example, a retardation plate, or, for example, two ⁇ /4 wavelength plates.
  • a combination may be used, or a combination of a plurality of wave plates may be used.
  • an optical rotator which is an element that rotates polarized light itself, may be used in addition to an element that rotates polarized light using a phase difference, such as a wave plate.
  • FIG. 11 is a diagram for explaining the configuration of the image display device 30 (LCOS) in this embodiment.
  • LCOS image display device 30
  • the same components as those in FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted.
  • 11 differs from FIG. 2 in that a liquid crystal layer 38, which is a polarization function element for changing the polarization angle, is added to the LCOS.
  • the liquid crystal layer 38 is a liquid crystal layer whose polarization angle can be arbitrarily changed.
  • the variation in the polarization angle can be adjusted and the contrast can be stabilized. can.
  • HMD HMD
  • 10 Illumination system
  • 20 PBS
  • 30 Image display device (LCOS)
  • 31 Cover glass
  • 32 Liquid crystal layer
  • 33 Display panel
  • 35 ⁇ /2 wavelength plate
  • 38 Liquid crystal layer
  • 40 projection system
  • 50 light guide section
  • 60 image display device (LCD)
  • 100 image display section

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  • Physics & Mathematics (AREA)
  • Nonlinear Science (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Mathematical Physics (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Liquid Crystal (AREA)

Abstract

Le but de la présente invention est de fournir un visiocasque avec lequel une détérioration de contraste peut être ajustée et améliorée avec une configuration simple.　Pour atteindre ce qui précède, l'invention concerne un dispositif de visiocasque comprenant : un dispositif d'affichage vidéo équipé d'une couche de cristaux liquides qui change un angle de polarisation à 90° et 0° ; un système d'irradiation qui fournit une lumière d'irradiation au dispositif d'affichage vidéo ; et un élément optique de polarisation qui guide la lumière d'irradiation vers le dispositif d'affichage vidéo et qui sélectionne la transmission/la réflexion en fonction de l'angle de polarisation de la lumière qui est modifiée par le dispositif d'affichage vidéo. Un élément fonctionnel de polarisation est disposé entre l'élément optique de polarisation et le dispositif d'affichage vidéo.
PCT/JP2021/042311 2021-02-05 2021-11-17 Dispositif de visiocasque WO2022168398A1 (fr)

Applications Claiming Priority (2)

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JP2021-017551 2021-02-05
JP2021017551A JP2022120575A (ja) 2021-02-05 2021-02-05 ヘッドマウントディスプレイ装置

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009063846A (ja) * 2007-09-06 2009-03-26 Fujifilm Corp 偏光制御システム及びプロジェクタ
JP2015059979A (ja) * 2013-09-17 2015-03-30 株式会社Ｊｖｃケンウッド 画像表示素子
WO2018135193A1 (fr) * 2017-01-20 2018-07-26 ソニー株式会社 Dispositif optique et dispositif d'affichage

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009063846A (ja) * 2007-09-06 2009-03-26 Fujifilm Corp 偏光制御システム及びプロジェクタ
JP2015059979A (ja) * 2013-09-17 2015-03-30 株式会社Ｊｖｃケンウッド 画像表示素子
WO2018135193A1 (fr) * 2017-01-20 2018-07-26 ソニー株式会社 Dispositif optique et dispositif d'affichage

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