WO2016136407A1 - Optical device and image display device - Google Patents

Optical device and image display device Download PDF

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Publication number
WO2016136407A1
WO2016136407A1 PCT/JP2016/053174 JP2016053174W WO2016136407A1 WO 2016136407 A1 WO2016136407 A1 WO 2016136407A1 JP 2016053174 W JP2016053174 W JP 2016053174W WO 2016136407 A1 WO2016136407 A1 WO 2016136407A1
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WO
WIPO (PCT)
Prior art keywords
optical
optical element
refractive
display surface
display
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PCT/JP2016/053174
Other languages
French (fr)
Japanese (ja)
Inventor
一臣 村上
新井　健雄
正充 佐藤
万 河村
Original Assignee
ソニー株式会社
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Publication of WO2016136407A1 publication Critical patent/WO2016136407A1/en

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    • 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—Arrangement of adaptations of instruments
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B17/00—Systems with reflecting surfaces, with or without refracting elements
    • G02B17/08—Catadioptric systems
    • 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
    • G02B27/02—Viewing or reading apparatus

Definitions

  • the technology disclosed in this specification relates to an optical device and an image display device that allow an observer to observe an enlarged virtual image of a display image.
  • Display devices for observing an enlarged virtual image of a display image such as a head-up display that projects an image on the observer's field of view, such as a windshield, are becoming widespread.
  • a virtual image observation provided with a reflection surface S1 for enlarging an image displayed on the display surface OP and a reflection surface S2 for correcting distortion caused by reflection on the reflection surface S1 (particularly distortion generated when the pupil is shifted).
  • Proposals have been made for devices (see, for example, Patent Document 1).
  • the reflecting surface S1 and the reflecting surface S2 are arranged in this order from the optical pupil EP side.
  • a virtual image observation apparatus using a free-form surface as a reflecting surface has a problem of resolution and distortion because of high sensitivity of aberration due to surface shape error.
  • positional accuracy by assembly is difficult because high accuracy is required.
  • an optical system using a plurality of reflecting surfaces has a problem that the optical path length becomes long and the apparatus becomes large.
  • the reflectance at each reflecting surface is not high, the luminance decreases each time the light is reflected, so that the image observed by the observer becomes dark.
  • An object of the technology disclosed in this specification is to provide an excellent optical device and an image display device that are easy to manufacture, can be configured in a small size, and allow an observer to observe an enlarged virtual image of a display image. It is to provide.
  • the technology disclosed in the present specification has been made in consideration of the above-mentioned problems, and the first aspect thereof is An optical device for observing a virtual image of an image displayed on a display surface at a position of an optical pupil, A reflection part having only one reflection surface disposed in an optical path between the display surface and the optical pupil; A refractive optical element disposed between the display surface and the reflective surface; Is an optical device.
  • the reflection surface of the optical device according to the first aspect has an optical axis that optically connects the center of the display surface and the center of the optical pupil. In contrast, it is arranged eccentrically.
  • the refractive optical element of the optical device includes light that optically connects the center of the display surface and the center of the optical pupil. It is arranged eccentrically with respect to the shaft.
  • the reflection surface of the optical device according to the first aspect has a negative power, and is configured to enlarge an image displayed on the display surface. Has been.
  • the refractive optical element of the optical device according to the first aspect has an effect that light passes through the medium and refracts light according to Snell's law. It consists of an element with
  • the refractive optical element of the optical device according to the first aspect is configured so that each light beam emitted from the display surface passes through the reflection surface. It is configured to correct various aberrations caused by the optical path difference that occurs up to the optical pupil.
  • the refractive optical element of the optical device has the light beam emitted from the display surface via the reflection surface. It has a surface shape that adjusts the optical path length to the optical pupil.
  • the refractive optical element of the optical device according to the first aspect has an angle at which each light beam emitted from the display surface is reflected by the reflection surface. The distortion of the virtual image due to the difference is corrected.
  • the refractive optical element of the optical device refracts each light beam emitted from the display surface to the reflective surface. The incident angle is adjusted.
  • any one surface or both surfaces of the refractive optical element of the optical device according to any one of the first to ninth aspects may be spherical or aspheric. It has a shape, anamorphic shape, or free-form surface shape.
  • the second derivative of Sag representing the height of the optical device according to the first aspect with respect to the direction parallel to the optical axis of the refractive optical element is the optical axis. It has a point that becomes 0 in the region other than the intersection with (that is, the sign of the second derivative of Sag changes in the region other than the origin).
  • an optical device according to any one of the first to tenth aspects includes a plurality of the refractive optical elements.
  • a part of the plurality of refractive optical elements of the optical device according to the twelfth aspect corrects the various aberrations or distortions, and the other part
  • the virtual image is configured to be enlarged.
  • the fourteenth aspect of the technology disclosed in this specification is: A display unit having a display surface for displaying an image; A reflection part having only one reflection surface disposed in an optical path between the display surface and an optical pupil for observing a virtual image of the image; A refractive optical element disposed between the display surface and the reflective surface;
  • the image display apparatus which comprises.
  • an excellent optical device and an image display device that are easy to manufacture, can be configured in a small size, and allow an observer to observe an enlarged virtual image of a display image suitably. Can be provided.
  • FIG. 1 is a diagram (cross-sectional view) schematically showing a configuration example of an image display device 100 to which the technology disclosed in this specification is applied.
  • FIG. 2 is a diagram (upper cross-sectional view) schematically showing a configuration example of the image display device 100 to which the technology disclosed in this specification is applied.
  • FIG. 3 is a diagram (perspective view) schematically showing a configuration example of the image display device 100 to which the technology disclosed in this specification is applied.
  • FIG. 4 is a diagram illustrating a state in which a fan-shaped distortion is generated in the virtual image due to the difference in the reflection angle of the light beam emitted from the display surface OP.
  • FIG. 5 is a diagram (cross-sectional view) illustrating another configuration example of the image display device 500 to which the technology disclosed in this specification is applied.
  • FIG. 6A is a diagram illustrating a state in which the optical element is not decentered with respect to the optical axis.
  • FIG. 6B is a diagram illustrating a state in which the optical element is tilted.
  • FIG. 6C is a diagram illustrating a state where the optical element is decentered with respect to the optical axis.
  • FIG. 7 is a diagram showing the Y L axis and the Z L axis on the local coordinate system set with reference to the refractive optical element 103.
  • FIG. 6A is a diagram illustrating a state in which the optical element is not decentered with respect to the optical axis.
  • FIG. 6B is a diagram illustrating a state in which the optical element is tilted.
  • FIG. 6C is a diagram illustrating a state where the optical element is decentered with respect to the optical axi
  • FIG. 8 is a diagram showing the X L axis and the Z L axis on the local coordinate system set with reference to the refractive optical element 103.
  • FIG. 9 is a diagram showing a cross-sectional shape of the refractive optical element 103.
  • FIG. 10 is a graph showing a cross-sectional profile of the refractive optical element 103 as Sag.
  • FIG. 11 is a graph showing a second derivative of the Sag shown in FIG.
  • FIG. 12 is a diagram for explaining the surface shape of the refractive optical element 103.
  • FIG. 13 is a diagram for explaining the surface shape of the refractive optical element 103.
  • FIG. 14 is a diagram for explaining the surface shape of the refractive optical element 103.
  • FIG. 15 is a diagram for explaining the surface shape of the refractive optical element 103.
  • FIG. 16 is a diagram for explaining the surface shape of the refractive optical element 103.
  • FIG. 1 to 3 schematically show a configuration example of an image display apparatus 100 to which the technology disclosed in this specification is applied.
  • 1 is a cross-sectional view of the image display device 100
  • FIG. 2 is a top cross-sectional view of the image display device 100
  • FIG. 3 is a perspective view of the image display device 100.
  • the illustrated image display device 100 includes a display unit 101 that displays an image on the display surface OP, and an optical system that guides light emitted from the display surface OP to the position of the optical pupil EP, and observes an enlarged virtual image on the display surface OP. It is comprised so that a person may observe.
  • the display unit 101 is a small multifunction information terminal such as a smartphone or a tablet, for example, and the display surface OP includes a display element such as a liquid crystal display device (LCD) or an organic EL element (OLED). Alternatively, the display surface OP may be a projected image of a screen.
  • a display element such as a liquid crystal display device (LCD) or an organic EL element (OLED).
  • the display surface OP may be a projected image of a screen.
  • the optical system is disposed between the reflection unit 102 including one reflection surface S1 disposed in the optical path between the display surface OP and the optical pupil EP, and between the display surface OP and the reflection surface S1 of the reflection unit 102.
  • the refractive optical element 103 is provided.
  • the term “refractive optical element” as used herein refers to an element having the action of light being transmitted through a medium (not reflected like a mirror) and refracting light according to Snell's law. It corresponds to the “lens”. 1 to 3 show only a single refractive optical element 103, two or more refractive optical elements may be arranged between the display surface OP and the reflective surface S1 (described later).
  • the reflection surface S1 of the reflection unit 102 may be either total reflection or semi-reflection.
  • the reflection unit 102 is disposed so that the reflection surface S1 faces the display surface OP and the optical pupil EP side.
  • the reflection unit 102 is configured as a windshield, and displays an enlarged virtual image of the display surface OP superimposed on the driver's field of view. .
  • the reflection surface S1 of the reflection unit 102 has negative power (that is, a concave mirror), and enlarges the image displayed on the display surface OP.
  • the refractive optical element 103 refracts the emitted light from the display surface OP to correct distortion caused by reflection on the reflection surface S1 of the reflection unit 102, and also corrects that the image forming position differs depending on the optical path difference. It has a free-form surface.
  • the optical system is configured to cause the enlarged virtual image of the display surface OP to be observed at the position of the optical pupil EP by guiding the light emitted from the display surface OP to the position of the optical pupil EP.
  • FIGS. 1 to 3 Although there are actually support members for supporting each of the display unit 101, the reflection unit 102, and the refractive optical element 103 at appropriate positions and postures, the illustration is omitted in FIGS. 1 to 3 for simplification. ing.
  • the direction perpendicular to the surface of the optical pupil EP (or the direction of the optical axis) is taken as the Z direction, and the direction parallel to the paper surface of FIG.
  • the direction perpendicular to the paper surface (in other words, the direction parallel to the paper surface of FIG. 2) is defined as the X direction.
  • a line that optically connects the center of the display surface OP and the center of the optical pupil EP is defined as an “optical axis” in the illustrated image display device 100 (the reflection surface S1 of the reflection unit 102 and the optical pupil EP are light beams).
  • the straight line connected by the axis is the Z axis).
  • FIGS. 1 and 2 can be referred to as a view of the image display device 100 as viewed from the ZX plane.
  • Each axis of XYZ shown in FIGS. 1 and 2 is a global coordinate system.
  • a local coordinate system can be set for the refractive optical element 103 with the direction of the optical axis as the Z direction.
  • the X L , Y L , and Z L axes on the local coordinate system set with reference to the refractive optical element 103 are shown in FIGS.
  • the reflecting surface S1 of the reflecting portion 102 and the refractive optical element 103 are arranged eccentrically with respect to the optical axis (for example, tilted about the X axis).
  • the decentering of the optical element here refers to the state where the optical element (the optical axis of the optical element itself) is tilted with respect to the optical axis of the image display apparatus 100 and the optical element (the optical axis thereof) of the image display apparatus 100.
  • FIG. 6A shows a state in which the optical element (lens) is not decentered with respect to the optical axis (of the image display device 100)
  • FIG. 6B shows the optical element with respect to the optical axis (or Z axis).
  • FIG. 6C shows a state where the optical element is decentered from the optical axis.
  • both the reflecting surface S1 of the reflecting portion 102 and the refractive optical element 103 are decentered (on the paper surface) with respect to the optical axis.
  • the refractive optical element 103 has a shape for correcting various aberrations such as distortion, and is disposed at an appropriate place. Referring to the cross-sectional view of FIG. 1, among the light rays emitted from the display surface OP of the display unit 101, a portion between the leftmost ray R1 and the rightmost ray R2 passes through the reflection surface S1 of the reflection unit 102. An optical path difference leading to the optical pupil EP occurs. For this reason, there is a concern that the positions at which the light rays R1 and R2 form an image are different and the resolution of the virtual image in the optical pupil EP is impaired.
  • the shape of the refractive optical element 103 (in the cross section) may be set so that the optical path lengths of the light rays R1 and R2 are equal.
  • the optical path length of the light beam R1 is shorter than the optical path length of the light beam R2.
  • the refractive optical element 103 may be formed in an uneven shape (wedge shape) such that the lens through which the light ray R1 passes is thick and the lens through which the light ray R2 passes is thin.
  • the refractive optical element 103 may have a cross-sectional shape that makes the optical path length until the light emitted from each pixel of the display unit 101 reaches the optical pupil EP uniform.
  • FIG. 4 shows a state in which fan-shaped distortion has occurred in the virtual image due to the difference in the reflection angle of the light beam emitted from the display surface OP. Therefore, each light beam is refracted by the refractive optical element 103 and the incident angle to the reflection surface S1 of the reflection unit 102 is changed, so that a virtual image without distortion can be observed with the optical pupil EP.
  • the refractive optical element 103 is non-reflective. It is a plane. Non-planar includes, for example, a spherical shape, an aspheric shape, an anamorphic shape, a free-form surface shape, and the like.
  • the refractive optical element 103 needs to be decentered (in the Y L direction) with respect to the optical axis (or Z L axis). In the case of the refractive optical element 103 having a free-form surface shape, the refractive optical element 103 does not necessarily have to be decentered.
  • the decentered arrangement tends to be an uneven shape.
  • the aberration (described above) can be corrected more satisfactorily.
  • an appropriate shape of the refractive optical element 103 can be determined using a technique well known in the art such as ray tracing simulation.
  • the surface shape of both surfaces may be non-planar as described above, or only one surface may be non-planar and the opposite side may be non-planar.
  • the surface may be a plane.
  • the surface of the refractive optical element 103 facing the reflecting surface S1 of the reflecting portion 102 is a flat surface, and the surface facing the display surface OP of the display portion 101 is non-planar. Each is formed.
  • refractive optical element 103 In the configuration example of the image display apparatus 100 shown in FIGS. 1 to 3, only a single refractive optical element 103 is drawn for convenience, but two or more refractive optical elements are provided between the display surface OP and the reflective surface S1. You may make it arrange
  • a plurality of refractive optical elements may be used for correcting various aberrations, some refractive optical elements may be used for correcting various aberrations, and the other part may further enlarge the virtual image. It is good also for the magnification.
  • the image display apparatus 100 to which the technology disclosed in this specification is applied allows an observer to observe an enlarged virtual image of a display image, but uses a refractive optical element and has a configuration in which a reflective surface (reflecting unit 102) is single. By doing so, an optical system with low sensitivity to various aberrations is obtained. Therefore, since the requirement of positional accuracy is relaxed by assembly accuracy and assembly, the device can be easily manufactured. Further, the image display device 100 has a single reflecting surface on the optical path of another path for obtaining an enlarged virtual image, and the optical path length is shortened, so that the optical system becomes a small configuration and the product becomes compact.
  • the optical pupil size can be enlarged with a wide angle of view (for example, the optical path lengths of light incident on the right and left eyes of the observer are equal to each other). You can enjoy comfortable viewing even if you shift the pupil.
  • the center of the observer's head (or the center of the body, or both eyes) is centered on the optical system (or the Z axis) of the image display apparatus 100. ), The centers of the left and right eyes are offset from each other in the left-right direction with respect to the center of the optical system.
  • the left and right eyes are at positions shifted by 32 millimeters from the center of the optical system.
  • the left eye is shifted by 64 millimeters from the center of the optical system.
  • the right eye is shifted by 64 millimeters from the center of the optical system.
  • the size of the optical pupil EP needs to be at least 64 millimeters in the X direction of the optical system.
  • the head when the observer views reclining, the head is often moved in the left-right direction (or the X direction of the optical system) rather than moving the head in the vertical direction (or the Y direction of the optical system). For this reason, it is preferable to enlarge the size of the optical pupil EP in the X direction. That is, the size of the optical pupil EP needs to be 64 millimeters or more in the X direction of the optical system.
  • the shape of the refractive optical element 103 in view of the above situation has a characteristic surface shape.
  • it has a characteristic surface shape in the X direction of the optical system in which the size of the optical pupil EP is enlarged.
  • FIG. 9 shows a cross-sectional shape of the refractive optical element 103 cut along a certain Z L X L plane 901 on the local coordinate system (described above).
  • FIG. 10 is a graph showing the cross-sectional profile of the refractive optical element 103 shown in FIG. 9 as Sag (sag amount).
  • the solid line denoted by reference numeral 1001 represents the sag of the refractive optical element 103.
  • a dotted line indicated by reference numeral 1002 represents a Sag having a spherical shape (simple R) in the paraxial region of the refractive optical element 103 for comparison.
  • the refractive optical element 103 in order to suppress distortion of the enlarged virtual image formed on the optical pupil EP, the refractive optical element 103 must have a gentle cross-sectional shape.
  • the shape of the refractive optical element 103 in the Y L direction is as already described with reference to FIG.
  • An optical path difference up to the optical pupil EP occurs between the leftmost light ray R1 and the rightmost light ray R2, the positions where the light rays R1 and R2 form an image are different, and the resolution of the virtual image in the optical pupil EP is different.
  • the shape of the refractive optical element 103 in the Y L direction is made such that the optical path lengths of the light rays R1 and R2 are equal. That is, as can be seen from FIG. 1, the refractive optical element 103 has an uneven thickness shape (wedge shape) in which the thickness of the lens through which the light ray R1 passes is thick and the thickness of the lens through which the light ray R2 passes is thin.
  • FIG. 12 shows a state in which the reflected light from the reflecting surface S1 having a negative power (that is, a concave mirror) (of the reflecting portion 102) is observed by the optical pupil EP.
  • the reflection surface S1 reflects irradiation light from the display surface OP (not shown in FIG. 12) of the display unit 101 (same as above).
  • the ZX plane shows a state of observation with the optical pupil EP (observer's eyes) arranged so as to coincide with the center of the optical system (that is, the Z axis), and the reflected light from the reflecting surface S1. Is imaged on a curved image plane as indicated by reference numeral 1201.
  • the image plane 1201 is curved because of reflection between light rays that have passed through the optical axis and light rays that have been emitted from the outermost periphery of the display surface OP among light rays emitted from the display surface OP of the display unit 101. This is because the angle reflected by the surface S1 is different (same as above).
  • FIG. 13 shows a state in which the reflected light from the reflecting surface S1 is observed on the optical pupil EP at a position shifted in the X direction from the center of the optical system (that is, the Z axis) on the ZX plane.
  • the image plane in this case is curved and inclined as indicated by reference numeral 1301.
  • the image surface 1301 is curved because the angles at which the light rays emitted from the display surface OP of the display unit 101 are reflected by the reflection surface S1 are different (same as above).
  • the image plane is inclined because the optical pupil EP is shifted from the center of the optical system, and the inclination increases according to the shift amount.
  • FIG. 14 shows the reflected light from the reflecting surface S1 when the refractive optical element 1401 made of a convex lens is disposed between the display surface OP and the reflecting surface S1 of the reflecting unit 102. That is, the ZX plane shows the state of observation with the optical pupil EP arranged so as to coincide with the Z axis).
  • the reflection surface S1 is a concave mirror having a negative power, and the reflection angle from the reflection surface S1 of each light beam irradiated from the display surface OP varies.
  • the reflection angle from the reflection surface S1 of each light beam irradiated from the display surface OP is adjusted by the refractive optical element 1401 made of a convex lens.
  • the curvature of the image plane observed at the optical pupil EP is corrected.
  • the reflected light from the reflecting surface S1 when the refractive optical element 1501 is disposed between the display surface OP and the reflecting surface S1 of the reflecting unit 102 is the center of the optical system (that is, Z A state of observing with the optical pupil EP at a position shifted in the X direction from the axis) is shown on the ZX plane.
  • the reflection surface S1 is a concave mirror having a negative power, and the reflection angle from the reflection surface S1 of each light beam irradiated from the display surface OP varies. Further, since the optical pupil EP is shifted from the center of the optical system, the image plane is inclined.
  • the refractive optical element 1501 has a shape in which a convex lens 1501A and a wedge 1501B are overlapped.
  • the reflection angle from the reflection surface S1 of each light beam irradiated from the display surface OP is adjusted by the convex lens 1501A portion of the refractive optical element 1501. Further, the inclination of the image plane is corrected by the wedge-shaped portion 1501B of the refractive optical element 1501. As a result, as indicated by reference numeral 1502, the curvature and inclination of the image plane observed with the optical pupil EP are corrected.
  • FIG. 16 shows a refractive optical element 1401 configured to correct curvature of the image plane when the optical pupil EP is arranged so as to coincide with the center of the optical system (that is, the Z axis), and the optical pupil EP.
  • the surface shape is as shown in FIG.
  • FIG. 5 schematically shows another configuration example (cross-sectional view) of the image display device 500 to which the technology disclosed in this specification is applied.
  • the image display apparatus 500 includes a display unit 501 that displays an image on the display surface OP, and an optical system that guides light emitted from the display surface OP to the position of the optical pupil EP, and provides an enlarged virtual image of the display surface OP to an observer. It is configured to be observed.
  • the optical system is disposed between the reflection unit 502 including one reflection surface disposed in the optical path between the display surface OP and the optical pupil EP, and between the display surface OP and the reflection surface of the reflection unit 502. And two refractive optical elements 503 and 504.
  • One difference between the image display device 500 and the image display device 100 shown in FIGS. 1 to 3 is that the angle ⁇ between the display surface OP of the display unit 501 and the reflection surface of the reflection unit 502 is widened. is there.
  • the angle ⁇ is widened, the refraction type optical elements 503 and 504 largely deviate from the optical path toward the optical pupil EP because the reflected light (enlarged virtual image) by the reflecting surface of the reflecting portion 502 can secure a good field of view for the observer. it can.
  • FIGS. 1 to 3 another difference between the image display device 500 and the image display device 100 shown in FIGS. 1 to 3 is that two refractive optical elements 503 and 504 are provided.
  • FIG. 5 when the angle ⁇ between the display surface OP of the display unit 501 and the reflection surface of the reflection unit 502 is widened, aberration due to decentering increases, and various aberrations are corrected only by the single refractive optical element 103. It will be difficult to do. For this reason, as shown in FIG. 5, it is preferable to correct various aberrations using two refractive optical elements 503 and 504 (or three or more refractive optical elements). Further, as described above, a plurality of refractive optical elements may be properly used for correcting various aberrations and for magnification of the magnified virtual image.
  • the image display device 500 shown in FIG. 5 also becomes an optical system with a low sensitivity to various aberrations by using (1) a configuration using a refractive optical element. (2) The optical system becomes compact and the product becomes compact. (3) The optical pupil size can be increased at a high angle of view by using a refractive optical element as an aberration correction lens. There is an advantage that a comfortable viewing can be performed even if the pupil is shifted.
  • the technology disclosed in this specification allows an observer to observe an enlarged virtual image on a display surface of a smartphone, a tablet terminal, a game machine, or the like, including a head-up display that displays information in the observer's field of view, such as a car windshield.
  • the present invention can be applied to various types of optical devices and image display devices.
  • the reflecting surface has negative power and enlarges an image displayed on the display surface.
  • the refractive optical element is composed of an element having a function of allowing light to pass through the medium and refracting the light according to Snell's law.
  • the refractive optical element corrects various aberrations caused by optical path differences that occur until each light beam emitted from the display surface reaches the optical pupil via the reflective surface.
  • the refractive optical element has a surface shape that adjusts an optical path length of each light beam emitted from the display surface to reach the optical pupil via the reflection surface.
  • the refractive optical element corrects distortion of the virtual image due to a difference in angle at which each light beam emitted from the display surface is reflected by the reflection surface.
  • the optical device according to (1) above. (9) The refractive optical element refracts each light beam emitted from the display surface and adjusts an incident angle on the reflection surface.
  • the optical device according to (1) above. (10) Either one or both surfaces of the refractive optical element has a spherical shape, an aspherical shape, an anamorphic shape, or a free-form surface shape.
  • the second derivative of Sag representing the height of the refractive optical element with respect to the direction parallel to the optical axis has a point that becomes 0 in a region other than the intersection with the optical axis (that is, the second derivative of Sag is The sign changes in areas other than the origin)
  • a plurality of the refractive optical elements are provided.
  • a part of the plurality of refractive optical elements corrects the aberrations or distortion, and the other part enlarges the virtual image.
  • a display unit having a display surface for displaying an image;
  • a reflection part having only one reflection surface disposed in an optical path between the display surface and an optical pupil for observing a virtual image of the image;
  • a refractive optical element disposed between the display surface and the reflective surface;
  • DESCRIPTION OF SYMBOLS 100 ... Image display apparatus 101 ... Display part, 102 ... Reflection part, 103 ... Refraction type optical element 500 ... Image display apparatus 501 ... Display part, 502 ... Reflection part 503,504 ... Refraction type optical element

Abstract

Provided is an optical device for causing an observer to observe an enlarged virtual image of a display image, the optical device being easily manufactured and configurable in a small size. An optical system is provided with a reflecting part 102 comprising one reflecting face provided in an optical path between a display face OP and an optical pupil EP, and a refractive optical element 103 provided between the display face OP and the reflecting face of the reflecting part 102. The reflecting face of the reflecting part 102 has a negative power and enlarges an image displayed on the display face OP. The refractive optical element 103 has a free-form surface whereby emitted light from the display face OP is refracted, and distortion caused by reflection by the reflecting face of the reflecting part 102 is corrected.

Description

光学装置並びに画像表示装置Optical device and image display device
　本明細書で開示する技術は、表示画像の拡大虚像を観察者に観察させる光学装置並びに画像表示装置に関する。 The technology disclosed in this specification relates to an optical device and an image display device that allow an observer to observe an enlarged virtual image of a display image.
　フロントガラスなど観察者の視界に画像を投影するヘッドアップディスプレイなど、表示画像の拡大虚像を観察させる表示装置が普及しつつある。 Display devices for observing an enlarged virtual image of a display image, such as a head-up display that projects an image on the observer's field of view, such as a windshield, are becoming widespread.
　例えば、表示面ＯＰに表示される画像を拡大する反射面Ｓ１と、反射面Ｓ１での反射によって生じる歪み（特に、瞳をシフトしたときに生じる歪み）を補正する反射面Ｓ２を備えた虚像観察装置について提案がなされている（例えば、特許文献１を参照のこと）。上記の虚像観察装置において、光学瞳ＥＰ側から、反射面Ｓ１、反射面Ｓ２の順に配置されている。 For example, a virtual image observation provided with a reflection surface S1 for enlarging an image displayed on the display surface OP and a reflection surface S2 for correcting distortion caused by reflection on the reflection surface S1 (particularly distortion generated when the pupil is shifted). Proposals have been made for devices (see, for example, Patent Document 1). In the virtual image observation apparatus, the reflecting surface S1 and the reflecting surface S2 are arranged in this order from the optical pupil EP side.
　しかしながら、上記のように、自由曲面を反射面として用いる虚像観察装置においては、面形状の誤差による収差の感度が高いため、解像感や歪曲の問題がある。また、複数の反射面を使用する光学系の場合、組み立てによる位置精度は高い精度が要求されるために困難である。また、複数の反射面を使用する光学系は、光路長が長くなり、装置が大型化してしまうという問題がある。さらに、各反射面での反射率が高くないと、反射する度に輝度が低下するため、観察者が観察する映像が暗くなってしまうという問題もある。 However, as described above, a virtual image observation apparatus using a free-form surface as a reflecting surface has a problem of resolution and distortion because of high sensitivity of aberration due to surface shape error. Further, in the case of an optical system using a plurality of reflecting surfaces, positional accuracy by assembly is difficult because high accuracy is required. In addition, an optical system using a plurality of reflecting surfaces has a problem that the optical path length becomes long and the apparatus becomes large. In addition, if the reflectance at each reflecting surface is not high, the luminance decreases each time the light is reflected, so that the image observed by the observer becomes dark.
特開２０１２－５８２９４号公報JP 2012-58294 A
　本明細書で開示する技術の目的は、製造が容易で、小型に構成することができ、表示画像の拡大虚像を観察者に好適に観察させることができる、優れた光学装置並びに画像表示装置を提供することにある。 An object of the technology disclosed in this specification is to provide an excellent optical device and an image display device that are easy to manufacture, can be configured in a small size, and allow an observer to observe an enlarged virtual image of a display image. It is to provide.
　本明細書で開示する技術は、上記課題を参酌してなされたものであり、その第１の側面は、
　表示面に表示された画像の虚像を光学瞳の位置で観察させる光学装置であって、
　前記表示面と前記光学瞳との間の光路中に配設された１つの反射面のみを持つ反射部と、
　前記表示面と前記反射面の間に配設された屈折型光学素子と、
を具備する光学装置である。 The technology disclosed in the present specification has been made in consideration of the above-mentioned problems, and the first aspect thereof is
An optical device for observing a virtual image of an image displayed on a display surface at a position of an optical pupil,
A reflection part having only one reflection surface disposed in an optical path between the display surface and the optical pupil;
A refractive optical element disposed between the display surface and the reflective surface;
Is an optical device.
　本明細書で開示する技術の第２の側面によれば、第１の側面に係る光学装置の前記反射面は、前記表示面の中心と前記光学瞳の中心とを光学的に結ぶ光軸に対して偏心して配設されている。 According to the second aspect of the technology disclosed in this specification, the reflection surface of the optical device according to the first aspect has an optical axis that optically connects the center of the display surface and the center of the optical pupil. In contrast, it is arranged eccentrically.
　本明細書で開示する技術の第３の側面によれば、第１の側面に係る光学装置の前記屈折型光学素子は、前記表示面の中心と前記光学瞳の中心とを光学的に結ぶ光軸に対して偏心して配設されている。 According to the third aspect of the technology disclosed in the present specification, the refractive optical element of the optical device according to the first aspect includes light that optically connects the center of the display surface and the center of the optical pupil. It is arranged eccentrically with respect to the shaft.
　本明細書で開示する技術の第４の側面によれば、第１の側面に係る光学装置の前記反射面は、負のパワーを持ち、前記表示面に表示される画像を拡大するように構成されている。 According to the fourth aspect of the technology disclosed in this specification, the reflection surface of the optical device according to the first aspect has a negative power, and is configured to enlarge an image displayed on the display surface. Has been.
　本明細書で開示する技術の第５の側面によれば、第１の側面に係る光学装置の前記屈折型光学素子は、光が媒体中を透過して、スネルの法則により光を屈折させる作用を持つ素子からなる。 According to the fifth aspect of the technology disclosed in this specification, the refractive optical element of the optical device according to the first aspect has an effect that light passes through the medium and refracts light according to Snell's law. It consists of an element with
　本明細書で開示する技術の第６の側面によれば、第１の側面に係る光学装置の前記屈折型光学素子は、前記表示面から射出される各光線が前記反射面を経由して前記光学瞳に至るまでに発生する光路差に起因する諸収差を補正するように構成されている。 According to a sixth aspect of the technology disclosed in the present specification, the refractive optical element of the optical device according to the first aspect is configured so that each light beam emitted from the display surface passes through the reflection surface. It is configured to correct various aberrations caused by the optical path difference that occurs up to the optical pupil.
　本明細書で開示する技術の第７の側面によれば、第１の側面に係る光学装置の前記屈折型光学素子は、前記表示面から射出される各光線が前記反射面を経由して前記光学瞳に至るまでの光路長を調整する面形状を有している。 According to a seventh aspect of the technology disclosed in this specification, the refractive optical element of the optical device according to the first aspect has the light beam emitted from the display surface via the reflection surface. It has a surface shape that adjusts the optical path length to the optical pupil.
　本明細書で開示する技術の第８の側面によれば、第１の側面に係る光学装置の前記屈折型光学素子は、前記表示面から射出される各光線が前記反射面によって反射される角度の相違に起因する前記虚像の歪曲を補正するように構成されている。 According to the eighth aspect of the technology disclosed in this specification, the refractive optical element of the optical device according to the first aspect has an angle at which each light beam emitted from the display surface is reflected by the reflection surface. The distortion of the virtual image due to the difference is corrected.
　本明細書で開示する技術の第９の側面によれば、第１の側面に係る光学装置の前記屈折型光学素子は、前記表示面から射出される各光線を屈折させて、前記反射面への入射角度を調整するように構成されている。 According to a ninth aspect of the technology disclosed in the present specification, the refractive optical element of the optical device according to the first aspect refracts each light beam emitted from the display surface to the reflective surface. The incident angle is adjusted.
　本明細書で開示する技術の第１０の側面によれば、第１乃至９のいずれかの側面に係る光学装置の前記屈折型光学素子のいずれか一方の面又は両面は、球面形状、非球面形状、アナモルフィック形状、又は自由曲面形状を有している。 According to the tenth aspect of the technology disclosed in this specification, any one surface or both surfaces of the refractive optical element of the optical device according to any one of the first to ninth aspects may be spherical or aspheric. It has a shape, anamorphic shape, or free-form surface shape.
　本明細書で開示する技術の第１１の側面によれば、第１の側面に係る光学装置の前記屈折型光学素子の光軸に平行な方向に対する高さを表すＳａｇの２次微分は光軸との交点以外の領域で０になる点を持つ（すなわち、Ｓａｇの２次微分は原点以外の領域で符号が変わる）ように構成されている。 According to the eleventh aspect of the technology disclosed in this specification, the second derivative of Sag representing the height of the optical device according to the first aspect with respect to the direction parallel to the optical axis of the refractive optical element is the optical axis. It has a point that becomes 0 in the region other than the intersection with (that is, the sign of the second derivative of Sag changes in the region other than the origin).
　本明細書で開示する技術の第１２の側面によれば、第１乃至１０のいずれかの側面に係る光学装置は、複数の前記屈折型光学素子を備えている。 According to a twelfth aspect of the technology disclosed in this specification, an optical device according to any one of the first to tenth aspects includes a plurality of the refractive optical elements.
　本明細書で開示する技術の第１３の側面によれば、第１２の側面に係る光学装置の複数の前記屈折型光学素子の一部は前記諸収差又は歪曲を補正し、他の一部は前記虚像を拡大するように構成されている。 According to the thirteenth aspect of the technology disclosed in this specification, a part of the plurality of refractive optical elements of the optical device according to the twelfth aspect corrects the various aberrations or distortions, and the other part The virtual image is configured to be enlarged.
　また、本明細書で開示する技術の第１４の側面は、
　画像を表示する表示面を有する表示部と、
　前記表示面と画像の虚像を観察する光学瞳との間の光路中に配設された１つの反射面のみを持つ反射部と、
　前記表示面と前記反射面の間に配設された屈折型光学素子と、
を具備する画像表示装置である。 The fourteenth aspect of the technology disclosed in this specification is:
A display unit having a display surface for displaying an image;
A reflection part having only one reflection surface disposed in an optical path between the display surface and an optical pupil for observing a virtual image of the image;
A refractive optical element disposed between the display surface and the reflective surface;
The image display apparatus which comprises.
　本明細書で開示する技術によれば、製造が容易で、小型に構成することができ、表示画像の拡大虚像を観察者に好適に観察させることができる、優れた光学装置並びに画像表示装置を提供することができる。 According to the technology disclosed in this specification, an excellent optical device and an image display device that are easy to manufacture, can be configured in a small size, and allow an observer to observe an enlarged virtual image of a display image suitably. Can be provided.
　なお、本明細書に記載された効果は、あくまでも例示であり、本発明の効果はこれに限定されるものではない。また、本発明が、上記の効果以外に、さらに付加的な効果を奏する場合もある。 In addition, the effect described in this specification is an illustration to the last, and the effect of this invention is not limited to this. In addition to the above effects, the present invention may have additional effects.
　本明細書で開示する技術のさらに他の目的、特徴や利点は、後述する実施形態や添付する図面に基づくより詳細な説明によって明らかになるであろう。 Other objects, features, and advantages of the technology disclosed in the present specification will become apparent from a more detailed description based on embodiments to be described later and the accompanying drawings.
図１は、本明細書で開示する技術を適用した画像表示装置１００の構成例を模式的に示した図（横断面図）である。FIG. 1 is a diagram (cross-sectional view) schematically showing a configuration example of an image display device 100 to which the technology disclosed in this specification is applied. 図２は、本明細書で開示する技術を適用した画像表示装置１００の構成例を模式的に示した図（上断面図）である。FIG. 2 is a diagram (upper cross-sectional view) schematically showing a configuration example of the image display device 100 to which the technology disclosed in this specification is applied. 図３は、本明細書で開示する技術を適用した画像表示装置１００の構成例を模式的に示した図（斜視図）である。FIG. 3 is a diagram (perspective view) schematically showing a configuration example of the image display device 100 to which the technology disclosed in this specification is applied. 図４は、表示面ＯＰから射出された光線の反射角の相違により、虚像に扇形の歪曲が発生した様子を示した図である。FIG. 4 is a diagram illustrating a state in which a fan-shaped distortion is generated in the virtual image due to the difference in the reflection angle of the light beam emitted from the display surface OP. 図５は、本明細書で開示する技術を適用した画像表示装置５００の他の構成例を示した図（横断面図）である。FIG. 5 is a diagram (cross-sectional view) illustrating another configuration example of the image display device 500 to which the technology disclosed in this specification is applied. 図６Ａは、光学素子が光軸に対して偏心していない状態を示した図である。FIG. 6A is a diagram illustrating a state in which the optical element is not decentered with respect to the optical axis. 図６Ｂは、光学素子がチルトしている状態を示した図である。FIG. 6B is a diagram illustrating a state in which the optical element is tilted. 図６Ｃは、光学素子が光軸に対しディセンターしている状態を示した図である。FIG. 6C is a diagram illustrating a state where the optical element is decentered with respect to the optical axis. 図７は、屈折型光学素子１０３を基準にして設定したローカル座標系上のＹL軸及びＺL軸を示した図である。FIG. 7 is a diagram showing the Y L axis and the Z L axis on the local coordinate system set with reference to the refractive optical element 103. 図８は、屈折型光学素子１０３を基準にして設定したローカル座標系上のＸL軸及びＺL軸を示した図である。FIG. 8 is a diagram showing the X L axis and the Z L axis on the local coordinate system set with reference to the refractive optical element 103. 図９は、屈折型光学素子１０３の断面形状を示した図である。FIG. 9 is a diagram showing a cross-sectional shape of the refractive optical element 103. 図１０は、屈折型光学素子１０３の断面形状のプロファイルをＳａｇとして表したグラフを示した図である。FIG. 10 is a graph showing a cross-sectional profile of the refractive optical element 103 as Sag. 図１１は、図１０に示したＳａｇの２次微分のグラフを示した図である。FIG. 11 is a graph showing a second derivative of the Sag shown in FIG. 図１２は、屈折型光学素子１０３の面形状を説明するための図である。FIG. 12 is a diagram for explaining the surface shape of the refractive optical element 103. 図１３は、屈折型光学素子１０３の面形状を説明するための図である。FIG. 13 is a diagram for explaining the surface shape of the refractive optical element 103. 図１４は、屈折型光学素子１０３の面形状を説明するための図である。FIG. 14 is a diagram for explaining the surface shape of the refractive optical element 103. 図１５は、屈折型光学素子１０３の面形状を説明するための図である。FIG. 15 is a diagram for explaining the surface shape of the refractive optical element 103. 図１６は、屈折型光学素子１０３の面形状を説明するための図である。FIG. 16 is a diagram for explaining the surface shape of the refractive optical element 103.
　以下、図面を参照しながら本明細書で開示する技術の実施形態について詳細に説明する。 Hereinafter, embodiments of the technology disclosed in this specification will be described in detail with reference to the drawings.
　図１～図３には、本明細書で開示する技術を適用した画像表示装置１００の構成例を模式的に示している。但し、図１は画像表示装置１００の横断面図、図２は画像表示装置１００の上断面図、図３は画像表示装置１００の斜視図とする。図示の画像表示装置１００は、表示面ＯＰに画像を表示する表示部１０１と、表示面ＯＰから射出される光を光学瞳ＥＰの位置まで導く光学系を備え、表示面ＯＰの拡大虚像を観察者に観察させるように構成されている。 1 to 3 schematically show a configuration example of an image display apparatus 100 to which the technology disclosed in this specification is applied. 1 is a cross-sectional view of the image display device 100, FIG. 2 is a top cross-sectional view of the image display device 100, and FIG. 3 is a perspective view of the image display device 100. The illustrated image display device 100 includes a display unit 101 that displays an image on the display surface OP, and an optical system that guides light emitted from the display surface OP to the position of the optical pupil EP, and observes an enlarged virtual image on the display surface OP. It is comprised so that a person may observe.
　表示部１０１は、例えばスマートフォンやタブレットなどの小型の多機能情報端末であり、その表示面ＯＰは、液晶表示装置（ＬＣＤ）や有機ＥＬ素子（ＯＬＥＤ）などの表示素子で構成される。あるいは、表示面ＯＰは、スクリーンの投影画像であってもよい。 The display unit 101 is a small multifunction information terminal such as a smartphone or a tablet, for example, and the display surface OP includes a display element such as a liquid crystal display device (LCD) or an organic EL element (OLED). Alternatively, the display surface OP may be a projected image of a screen.
　光学系は、表示面ＯＰと光学瞳ＥＰとの間の光路中に配設された１面の反射面Ｓ１からなる反射部１０２と、表示面ＯＰと反射部１０２の反射面Ｓ１の間に配設された屈折型光学素子１０３で構成される。本明細書で言う「屈折型光学素子」とは、光が媒体中を透過（ミラーのような反射ではない）して、スネルの法則により光を屈折させる作用を持つ素子のことであり、一般に言う「レンズ」に相当する。図１～図３では、単一の屈折型光学素子１０３しか描いていないが、２以上の屈折型光学素子が表示面ＯＰと反射面Ｓ１の間に配設される場合もある（後述）。また、反射部１０２の反射面Ｓ１は、全反射又は半反射のいずれでもよい。反射部１０２は、反射面Ｓ１が表示面ＯＰと光学瞳ＥＰ側を向くように配設されている。例えば、画像表示装置１００が車載用のヘッドアップディスプレイとして適用される場合、反射部１０２はフロントガラスとして構成され、運転者の視界に、表示面ＯＰの拡大虚像を重畳して表示することになる。 The optical system is disposed between the reflection unit 102 including one reflection surface S1 disposed in the optical path between the display surface OP and the optical pupil EP, and between the display surface OP and the reflection surface S1 of the reflection unit 102. The refractive optical element 103 is provided. The term “refractive optical element” as used herein refers to an element having the action of light being transmitted through a medium (not reflected like a mirror) and refracting light according to Snell's law. It corresponds to the “lens”. 1 to 3 show only a single refractive optical element 103, two or more refractive optical elements may be arranged between the display surface OP and the reflective surface S1 (described later). Further, the reflection surface S1 of the reflection unit 102 may be either total reflection or semi-reflection. The reflection unit 102 is disposed so that the reflection surface S1 faces the display surface OP and the optical pupil EP side. For example, when the image display device 100 is applied as an in-vehicle head-up display, the reflection unit 102 is configured as a windshield, and displays an enlarged virtual image of the display surface OP superimposed on the driver's field of view. .
　反射部１０２の反射面Ｓ１は負のパワーを持ち（すなわち、凹面鏡であり）、表示面ＯＰに表示される画像を拡大する。また、屈折型光学素子１０３は、表示面ＯＰから射出光を屈折させて、反射部１０２の反射面Ｓ１での反射によって生じる歪みを補正するとともに、光路差によって結像する位置が異なることを補正するような自由曲面を持つ。要するに、光学系は、表示面ＯＰから射出される光を光学瞳ＥＰの位置まで導くことにより、表示面ＯＰの拡大虚像を光学瞳ＥＰの位置で観察させるように構成されている。 The reflection surface S1 of the reflection unit 102 has negative power (that is, a concave mirror), and enlarges the image displayed on the display surface OP. In addition, the refractive optical element 103 refracts the emitted light from the display surface OP to correct distortion caused by reflection on the reflection surface S1 of the reflection unit 102, and also corrects that the image forming position differs depending on the optical path difference. It has a free-form surface. In short, the optical system is configured to cause the enlarged virtual image of the display surface OP to be observed at the position of the optical pupil EP by guiding the light emitted from the display surface OP to the position of the optical pupil EP.
　なお、表示部１０１、反射部１０２、屈折型光学素子１０３の各々を適切な位置及び姿勢で支持する支持部材が現実には存在するが、図１乃至図３では簡素化のため図示を省略している。 Although there are actually support members for supporting each of the display unit 101, the reflection unit 102, and the refractive optical element 103 at appropriate positions and postures, the illustration is omitted in FIGS. 1 to 3 for simplification. ing.
　便宜上、光学瞳ＥＰの面に垂直な方向（若しくは、光軸の方向）をＺ方向とし、Ｚ方向に垂直な２方向のうち、図１の紙面に平行な方向をＹ方向とし、図１の紙面に垂直な方向（言い換えれば、図２の紙面に平行な方向）をＸ方向とする。また、表示面ＯＰの中心と光学瞳ＥＰの中心とを光学的に結ぶ線を、図示の画像表示装置１００における「光軸」と定義する（反射部１０２の反射面Ｓ１と光学瞳ＥＰを光軸で結んだ直線をＺ軸とする）。図１は画像表示装置１００をＹＺ平面で見た図、図２は画像表示装置１００をＺＸ平面で見た図ということができる。図１及び図２に示したＸＹＺの各軸は、グローバルな座標系である。屈折型光学素子１０３に対して、光軸の方向をＺ方向として、ローカル座標系を設定することができる。屈折型光学素子１０３を基準にして設定したローカル座標系上のＸL、ＹL、ＺLの各軸を、図７及び図８に示しておく。 For convenience, the direction perpendicular to the surface of the optical pupil EP (or the direction of the optical axis) is taken as the Z direction, and the direction parallel to the paper surface of FIG. The direction perpendicular to the paper surface (in other words, the direction parallel to the paper surface of FIG. 2) is defined as the X direction. In addition, a line that optically connects the center of the display surface OP and the center of the optical pupil EP is defined as an “optical axis” in the illustrated image display device 100 (the reflection surface S1 of the reflection unit 102 and the optical pupil EP are light beams). The straight line connected by the axis is the Z axis). FIG. 1 can be said to be a view of the image display device 100 as viewed in the YZ plane, and FIG. 2 can be referred to as a view of the image display device 100 as viewed from the ZX plane. Each axis of XYZ shown in FIGS. 1 and 2 is a global coordinate system. A local coordinate system can be set for the refractive optical element 103 with the direction of the optical axis as the Z direction. The X L , Y L , and Z L axes on the local coordinate system set with reference to the refractive optical element 103 are shown in FIGS.
　反射部１０２の反射面Ｓ１と屈折型光学素子１０３は、光軸に対して偏心（例えば、Ｘ軸回りにチルト）して配置されている。ここで言う光学素子の偏心は、光学素子（光学素子自体の光軸）が画像表示装置１００の光軸に対してチルトしている状態と、光学素子（の光軸）が画像表示装置１００の光軸からディセンターしている状態の２種類が挙げられる。参考のため、図６Ａには光学素子（レンズ）が（画像表示装置１００の）光軸に対して偏心していない状態を示し、図６Ｂには光学素子が光軸（若しくは、Ｚ軸）に対して（Ｘ軸回りに）チルトしている状態を示し、図６Ｃには光学素子が光軸からディセンターしている状態を示している。反射部１０２の反射面Ｓ１と屈折型光学素子１０３の「偏心」に話を戻すと、反射部１０２の反射面Ｓ１と屈折型光学素子１０３はいずれも、光軸に対して偏心（紙面上で、光軸に対しＸ軸回りにチルト）して配置されている。 The reflecting surface S1 of the reflecting portion 102 and the refractive optical element 103 are arranged eccentrically with respect to the optical axis (for example, tilted about the X axis). The decentering of the optical element here refers to the state where the optical element (the optical axis of the optical element itself) is tilted with respect to the optical axis of the image display apparatus 100 and the optical element (the optical axis thereof) of the image display apparatus 100. There are two types that are decentered from the optical axis. For reference, FIG. 6A shows a state in which the optical element (lens) is not decentered with respect to the optical axis (of the image display device 100), and FIG. 6B shows the optical element with respect to the optical axis (or Z axis). FIG. 6C shows a state where the optical element is decentered from the optical axis. Returning to “eccentricity” of the reflecting surface S1 of the reflecting portion 102 and the refractive optical element 103, both the reflecting surface S1 of the reflecting portion 102 and the refractive optical element 103 are decentered (on the paper surface) with respect to the optical axis. , Tilted about the X axis with respect to the optical axis).
　屈折型光学素子１０３は、歪曲などの諸収差を補正するための形状を有し、適切な場所に配設される。図１の横断面図を参照すると、表示部１０１の表示面ＯＰから射出した光線のうち、最左端の光線Ｒ１と最右端の光線Ｒ２の間では、反射部１０２の反射面Ｓ１を経由して光学瞳ＥＰに至るまでの光路差が発生する。このため、光線Ｒ１と光線Ｒ２で結像する位置が異なり、光学瞳ＥＰにおける虚像の解像感が損なわれることが懸念される。そこで、屈折型光学素子１０３の（横断面の）形状を、光線Ｒ１と光線Ｒ２の光路長が等しくするような形状にすればよい。図１に示す例では、光線Ｒ１の光路長が光線Ｒ２の光路長よりも短い。このような場合、屈折型光学素子１０３は、光線Ｒ１が通過するレンズの厚みは厚く、光線Ｒ２が通過するレンズの厚みは薄いという偏肉の形状（楔形の形状）にすればよい。より一般化して言うと、屈折型光学素子１０３を、表示部１０１の各画素から射出する光線が光学瞳ＥＰに至るまでの光路長を均一にするような横断面の形状にすればよい。 The refractive optical element 103 has a shape for correcting various aberrations such as distortion, and is disposed at an appropriate place. Referring to the cross-sectional view of FIG. 1, among the light rays emitted from the display surface OP of the display unit 101, a portion between the leftmost ray R1 and the rightmost ray R2 passes through the reflection surface S1 of the reflection unit 102. An optical path difference leading to the optical pupil EP occurs. For this reason, there is a concern that the positions at which the light rays R1 and R2 form an image are different and the resolution of the virtual image in the optical pupil EP is impaired. Therefore, the shape of the refractive optical element 103 (in the cross section) may be set so that the optical path lengths of the light rays R1 and R2 are equal. In the example shown in FIG. 1, the optical path length of the light beam R1 is shorter than the optical path length of the light beam R2. In such a case, the refractive optical element 103 may be formed in an uneven shape (wedge shape) such that the lens through which the light ray R1 passes is thick and the lens through which the light ray R2 passes is thin. More generally, the refractive optical element 103 may have a cross-sectional shape that makes the optical path length until the light emitted from each pixel of the display unit 101 reaches the optical pupil EP uniform.
　また、図２の上断面図を参照すると、表示部１０１の表示面ＯＰから射出された光線のうち、光軸上を通過する光線Ｒ３と、表示面ＯＰの最外周から射出された光線Ｒ４とでは、反射部１０２の反射面Ｓ１によって反射される角度が異なるため、光学瞳ＥＰにおける虚像には歪曲が発生し、観察者の快適な視聴を損なうことが懸念される。図４には、表示面ＯＰから射出された光線の反射角の相違により、虚像に扇形の歪曲が発生した様子を示している。そこで、屈折型光学素子１０３により各光線を屈折させて、反射部１０２の反射面Ｓ１への入射角度を変化させることで、光学瞳ＥＰで歪曲のない虚像を観察できるようにすることができる。 2, among the light beams emitted from the display surface OP of the display unit 101, the light beam R3 passing on the optical axis, and the light beam R4 emitted from the outermost periphery of the display surface OP. Then, since the angle reflected by the reflection surface S1 of the reflection unit 102 is different, the virtual image in the optical pupil EP is distorted, and there is a concern that the viewer's comfortable viewing may be impaired. FIG. 4 shows a state in which fan-shaped distortion has occurred in the virtual image due to the difference in the reflection angle of the light beam emitted from the display surface OP. Therefore, each light beam is refracted by the refractive optical element 103 and the incident angle to the reflection surface S1 of the reflection unit 102 is changed, so that a virtual image without distortion can be observed with the optical pupil EP.
　上記のような、表示部１０１の表示面ＯＰから射出される各光線の光路長の調整と反射部１０２の反射面Ｓ１への入射角度の調整という２つの観点から、屈折型光学素子１０３は非平面である。非平面とは、例えば球面形状、非球面形状、アナモルフィック形状、自由曲面形状などである。屈折型光学素子１０３は、光軸（若しくは、ＺL軸）に対して（ＹL方向に）偏心して配置する必要がある。自由曲面形状を持つ屈折型光学素子１０３の場合は必ずしも屈折型光学素子１０３を偏心して配置する必要はないが、偏心して配置をした方が偏肉の形状になり易く、光路長の調整により諸収差（前述）をさらに良好に補正することができるようになる。例えば、光線追跡シミュレーションなど当業界において周知の手法を用いて、屈折型光学素子１０３の適切な形状を決定することができる。 From the above two viewpoints, adjustment of the optical path length of each light beam emitted from the display surface OP of the display unit 101 and adjustment of the incident angle to the reflection surface S1 of the reflection unit 102, the refractive optical element 103 is non-reflective. It is a plane. Non-planar includes, for example, a spherical shape, an aspheric shape, an anamorphic shape, a free-form surface shape, and the like. The refractive optical element 103 needs to be decentered (in the Y L direction) with respect to the optical axis (or Z L axis). In the case of the refractive optical element 103 having a free-form surface shape, the refractive optical element 103 does not necessarily have to be decentered. However, if the refractive optical element 103 is decentered, the decentered arrangement tends to be an uneven shape. The aberration (described above) can be corrected more satisfactorily. For example, an appropriate shape of the refractive optical element 103 can be determined using a technique well known in the art such as ray tracing simulation.
　なお、屈折型光学素子１０３が１枚の光学レンズで構成される場合、その両面の面形状を上記のような非平面にしてもよいし、片側の面のみを非平面にしてその反対側の面を平面としてもよい。図１～図３に示す例では、屈折型光学素子１０３の、反射部１０２の反射面Ｓ１と対向する側の面が平面に、表示部１０１の表示面ＯＰと対向する側の面が非平面に、それぞれ形成されている。 When the refractive optical element 103 is composed of a single optical lens, the surface shape of both surfaces may be non-planar as described above, or only one surface may be non-planar and the opposite side may be non-planar. The surface may be a plane. In the example shown in FIGS. 1 to 3, the surface of the refractive optical element 103 facing the reflecting surface S1 of the reflecting portion 102 is a flat surface, and the surface facing the display surface OP of the display portion 101 is non-planar. Each is formed.
　図１～図３に示した画像表示装置１００の構成例では、便宜上、単一の屈折型光学素子１０３しか描いていないが、２以上の屈折型光学素子が表示面ＯＰと反射面Ｓ１の間に配設するようにしてもよい。例えば、複数の屈折型光学素子をすべて諸収差の補正に使用してもよいし、一部の屈折型光学素子は諸収差の補正用とするとともに、他の一部は虚像をさらに拡大するための倍率用としてもよい。 In the configuration example of the image display apparatus 100 shown in FIGS. 1 to 3, only a single refractive optical element 103 is drawn for convenience, but two or more refractive optical elements are provided between the display surface OP and the reflective surface S1. You may make it arrange | position to. For example, a plurality of refractive optical elements may be used for correcting various aberrations, some refractive optical elements may be used for correcting various aberrations, and the other part may further enlarge the virtual image. It is good also for the magnification.
　本明細書で開示する技術を適用した画像表示装置１００は、表示画像の拡大虚像を観察者に観察させるが、屈折型光学素子を用い、反射面（反射部１０２）を単一とした構成にすることで、諸収差に対する感度の緩い光学系となる。したがって、組み立て精度や組み立てにより位置精度の要求が緩くなるので、装置の製造がし易くなる。また、画像表示装置１００は、拡大虚像を得る他路の光路上の反射面は単一であり、光路長が短縮されるので、光学系が小型な構成となり、製品がコンパクトになる。また、収差補正レンズとして屈折型光学素子を使用することで、広い画角で光学瞳サイズを拡大でき（例えば、観察者の右眼と左眼にそれぞれ入射する光の光路長が等しくなるようにすることができ）、瞳をシフトさせても快適な視聴をすることができる。 The image display apparatus 100 to which the technology disclosed in this specification is applied allows an observer to observe an enlarged virtual image of a display image, but uses a refractive optical element and has a configuration in which a reflective surface (reflecting unit 102) is single. By doing so, an optical system with low sensitivity to various aberrations is obtained. Therefore, since the requirement of positional accuracy is relaxed by assembly accuracy and assembly, the device can be easily manufactured. Further, the image display device 100 has a single reflecting surface on the optical path of another path for obtaining an enlarged virtual image, and the optical path length is shortened, so that the optical system becomes a small configuration and the product becomes compact. Further, by using a refractive optical element as an aberration correction lens, the optical pupil size can be enlarged with a wide angle of view (for example, the optical path lengths of light incident on the right and left eyes of the observer are equal to each other). You can enjoy comfortable viewing even if you shift the pupil.
　ここで、光学瞳ＥＰのサイズについてさらに詳細に検討してみる。 Here, we will examine the size of the optical pupil EP in more detail.
　観察者が表示面ＯＰの拡大虚像を両眼で視聴する際において、画像表示装置１００の光学系の中心（若しくは、Ｚ軸）に、観察者の頭の中心（若しくは、体の中心、又は両目の中間）を合わせた場合、左右の目の中心は光学系の中心に対してそれぞれ左右方向にずれた位置にある。 When the observer views the enlarged virtual image of the display surface OP with both eyes, the center of the observer's head (or the center of the body, or both eyes) is centered on the optical system (or the Z axis) of the image display apparatus 100. ), The centers of the left and right eyes are offset from each other in the left-right direction with respect to the center of the optical system.
　一般的には左右の目の間隔は６４ミリメートルと言われているので、光学系の中心から左右にそれぞれ３２ミリメートルだけシフトした位置に左右の目があることになる。例えば、右目を光学系の中心に合わせると、左目は光学系の中心から６４ミリメートルだけシフトした位置になる。逆に左目を光学系の中心に合わせると、右目は光学系の中心から６４ミリメートルだけシフトした位置になる。したがって、画像表示装置１００による拡大虚像を両目で観察することを想定すると、光学瞳ＥＰのサイズは少なくとも光学系のＸ方向に６４ミリメートルは必要であると言える。 Generally, since the distance between the left and right eyes is said to be 64 millimeters, the left and right eyes are at positions shifted by 32 millimeters from the center of the optical system. For example, when the right eye is aligned with the center of the optical system, the left eye is shifted by 64 millimeters from the center of the optical system. Conversely, when the left eye is matched with the center of the optical system, the right eye is shifted by 64 millimeters from the center of the optical system. Accordingly, assuming that the enlarged virtual image by the image display device 100 is observed with both eyes, it can be said that the size of the optical pupil EP needs to be at least 64 millimeters in the X direction of the optical system.
　また、観察者がリクライニング視聴する場合においては、頭を上下方向（若しくは、光学系のＹ方向）に移動させるよりも、左右方向（若しくは、光学系のＸ方向）に移動させることが多い。このため、光学瞳ＥＰのサイズをＸ方向に拡大することが好ましい。つまり、光学瞳ＥＰのサイズとしては、光学系のＸ方向に６４ミリメートル以上必要ということになる。 Also, when the observer views reclining, the head is often moved in the left-right direction (or the X direction of the optical system) rather than moving the head in the vertical direction (or the Y direction of the optical system). For this reason, it is preferable to enlarge the size of the optical pupil EP in the X direction. That is, the size of the optical pupil EP needs to be 64 millimeters or more in the X direction of the optical system.
　上記のような状況を鑑みた屈折型光学素子１０３の形状は、特徴的な面形状を有することになる。特に、光学瞳ＥＰのサイズを拡大した光学系のＸ方向に特徴的な面形状を有する。 The shape of the refractive optical element 103 in view of the above situation has a characteristic surface shape. In particular, it has a characteristic surface shape in the X direction of the optical system in which the size of the optical pupil EP is enlarged.
　図９には、屈折型光学素子１０３を、ローカル座標系（前述）上のあるＺLＸL平面９０１で切断した断面の形状を示している。また、図１０には、図９に示した屈折型光学素子１０３の断面形状のプロファイルをＳａｇ（サグ量）として表したグラフを示している。ここで言うＳａｇとは、光学素子の光軸（すなわち、ローカル座標系上のＺL軸）に平行な方向に対する高さを表す値（この例では、ＸL＝０と、あるＸL座標との高さの差）である。より厳密には、Ｓａｇは、光学素子の表面と光軸（すなわち、ローカル座標系上のＺL軸）の交点を含む光軸と直交する平面（すなわち、ＸLＹL平面）を基準に、光軸（ＺL＝０）からの距離ＸLに対して平面（ＸLＹL平面）から光学素子の表面の形状までの距離と言うこともできる。 FIG. 9 shows a cross-sectional shape of the refractive optical element 103 cut along a certain Z L X L plane 901 on the local coordinate system (described above). FIG. 10 is a graph showing the cross-sectional profile of the refractive optical element 103 shown in FIG. 9 as Sag (sag amount). Here, Sag is a value representing a height in a direction parallel to the optical axis of the optical element (that is, the Z L axis on the local coordinate system) (in this example, X L = 0, a certain X L coordinate, Difference in height). More precisely, Sag is based on a plane orthogonal to the optical axis including the intersection of the surface of the optical element and the optical axis (that is, the Z L axis on the local coordinate system) (that is, the X L Y L plane). It can also be said to be the distance from the plane (X L Y L plane) to the shape of the surface of the optical element with respect to the distance X L from the optical axis (Z L = 0).
　図１０中、参照番号１００１で示す実線は、屈折型光学素子１０３のＳａｇを表している。また、同図中、参照番号１００２で示す点線は、比較のため、屈折型光学素子１０３の近軸領域で球面形状（単純Ｒ）をしたＳａｇを表している。図１０に示したグラフから分かるように、光学瞳ＥＰに結像される拡大虚像の歪曲を抑えるために、屈折型光学素子１０３は緩やかな断面形状にしなければならない。 10, the solid line denoted by reference numeral 1001 represents the sag of the refractive optical element 103. Further, in the figure, a dotted line indicated by reference numeral 1002 represents a Sag having a spherical shape (simple R) in the paraxial region of the refractive optical element 103 for comparison. As can be seen from the graph shown in FIG. 10, in order to suppress distortion of the enlarged virtual image formed on the optical pupil EP, the refractive optical element 103 must have a gentle cross-sectional shape.
　図１０に示したＳａｇでは屈折型光学素子１０３の断面形状の特徴が分かり難いかもしれないので、Ｓａｇを２次微分することでその特徴を明確にしてみる。図１１には、図１０に示したＳａｇの２次微分のグラフを示している。Ｓａｇの２次微分のグラフを見ると、原点（すなわち、ＹL＝０）以外のある領域で０になる座標（変曲点）が存在し、それ以降は正負の符号が変わって０以下となることが分かる。つまり、緩やかな断面形状となる屈折型光学素子１０３のＳａｇの２次微分においては、変曲点となる座標が原点以外に存在する（変曲点以降は０以下になる）ことになる。 Since the characteristics of the cross-sectional shape of the refractive optical element 103 may be difficult to understand with the Sag shown in FIG. 10, the characteristics will be clarified by second-order differentiation of the Sag. FIG. 11 shows a graph of the second derivative of the Sag shown in FIG. Looking at the second-order derivative graph of Sag, there is a coordinate (inflection point) that becomes 0 in a certain region other than the origin (that is, Y L = 0), and after that, the sign of positive and negative changes and becomes 0 or less. I understand that That is, in the second derivative of the Sag of the refractive optical element 103 having a gentle cross-sectional shape, the inflection point has a coordinate other than the origin (below the inflection point, it becomes 0 or less).
　なお、ここでは図示を省略するが、球面形状（すなわち、単純Ｒ）をした光学素子の場合、原点（すなわち、ＹL＝０）以外の領域で０になる座標は存在せず、Ｓａｇは常に０以下である。 Although not shown here, in the case of an optical element having a spherical shape (that is, simple R), there is no coordinate that becomes 0 in an area other than the origin (that is, Y L = 0), and Sag is always 0 or less.
　また、屈折型光学素子１０３のＹL方向の形状については、図１を参照しながら既に説明した通りである。最左端の光線Ｒ１と最右端の光線Ｒ２の間では光学瞳ＥＰに至るまでの光路差が発生し、光線Ｒ１と光線Ｒ２で結像する位置が異なり、光学瞳ＥＰにおける虚像の解像感が損なわれることが懸念される。このため、屈折型光学素子１０３のＹL方向の形状を、光線Ｒ１と光線Ｒ２の光路長が等しくするような形状にする。すなわち、屈折型光学素子１０３は、図１から分かるように、光線Ｒ１が通過するレンズの厚みは厚く、光線Ｒ２が通過するレンズの厚みは薄いという偏肉の形状（楔形の形状）となる。 The shape of the refractive optical element 103 in the Y L direction is as already described with reference to FIG. An optical path difference up to the optical pupil EP occurs between the leftmost light ray R1 and the rightmost light ray R2, the positions where the light rays R1 and R2 form an image are different, and the resolution of the virtual image in the optical pupil EP is different. There is concern about damage. For this reason, the shape of the refractive optical element 103 in the Y L direction is made such that the optical path lengths of the light rays R1 and R2 are equal. That is, as can be seen from FIG. 1, the refractive optical element 103 has an uneven thickness shape (wedge shape) in which the thickness of the lens through which the light ray R1 passes is thick and the thickness of the lens through which the light ray R2 passes is thin.
　屈折型光学素子１０３が図１０に示したような面形状になる理由について、図１２乃至図１６を参照しながら説明する。 The reason why the refractive optical element 103 has the surface shape as shown in FIG. 10 will be described with reference to FIGS.
　図１２には、負のパワーを持つ（すなわち、凹面鏡の）（反射部１０２の）反射面Ｓ１からの反射光を光学瞳ＥＰで観察する様子を示している。反射面Ｓ１は、表示部１０１の表示面ＯＰ（図１２では図示を省略）からの照射光を反射するものとする（同上）。図１２では、光学系の中心（すなわち、Ｚ軸）に一致するように配置された光学瞳ＥＰ（観察者の目）で観察する様子をＺＸ平面で示しており、反射面Ｓ１からの反射光は、参照番号１２０１で示すように、湾曲している像面上に結像している。像面１２０１が湾曲しているのは、表示部１０１の表示面ＯＰから射出された光線のうち、光軸上を通過する光線と、表示面ＯＰの最外周から射出された光線とでは、反射面Ｓ１によって反射される角度が異なることに起因する（同上）。 FIG. 12 shows a state in which the reflected light from the reflecting surface S1 having a negative power (that is, a concave mirror) (of the reflecting portion 102) is observed by the optical pupil EP. The reflection surface S1 reflects irradiation light from the display surface OP (not shown in FIG. 12) of the display unit 101 (same as above). In FIG. 12, the ZX plane shows a state of observation with the optical pupil EP (observer's eyes) arranged so as to coincide with the center of the optical system (that is, the Z axis), and the reflected light from the reflecting surface S1. Is imaged on a curved image plane as indicated by reference numeral 1201. The image plane 1201 is curved because of reflection between light rays that have passed through the optical axis and light rays that have been emitted from the outermost periphery of the display surface OP among light rays emitted from the display surface OP of the display unit 101. This is because the angle reflected by the surface S1 is different (same as above).
　また、図１３には、光学系の中心（すなわち、Ｚ軸）からＸ方向にシフトした位置の光学瞳ＥＰで反射面Ｓ１からの反射光を観察する様子をＺＸ平面で示している。この場合の像面は、参照番号１３０１で示すように、湾曲しているとともに傾いている。像面１３０１が湾曲しているのは、表示部１０１の表示面ＯＰから射出された各光線が反射面Ｓ１によって反射される角度が異なることに起因する（同上）。また、像面が傾いているのは、光学瞳ＥＰが光学系の中心からシフトしているためで、シフト量に応じて傾きは大きくなる。 FIG. 13 shows a state in which the reflected light from the reflecting surface S1 is observed on the optical pupil EP at a position shifted in the X direction from the center of the optical system (that is, the Z axis) on the ZX plane. The image plane in this case is curved and inclined as indicated by reference numeral 1301. The image surface 1301 is curved because the angles at which the light rays emitted from the display surface OP of the display unit 101 are reflected by the reflection surface S1 are different (same as above). Further, the image plane is inclined because the optical pupil EP is shifted from the center of the optical system, and the inclination increases according to the shift amount.
　また、図１４には、表示面ＯＰと反射部１０２の反射面Ｓ１の間に、凸レンズからなる屈折型光学素子１４０１を配置した場合の、反射面Ｓ１からの反射光を、光学系の中心（すなわち、Ｚ軸）に一致するように配置された光学瞳ＥＰで観察する様子を、ＺＸ平面で示している。反射面Ｓ１は、負のパワーを持つ凹面鏡であり、表示面ＯＰから照射される各光線の反射面Ｓ１からの反射角度はまちまちである。図１４に示す例では、凸レンズからなる屈折型光学素子１４０１によって、表示面ＯＰから照射される各光線の反射面Ｓ１からの反射角度が調整される。この結果、参照番号１４０２で示すように、光学瞳ＥＰで観察される像面の湾曲は補正されている。 FIG. 14 shows the reflected light from the reflecting surface S1 when the refractive optical element 1401 made of a convex lens is disposed between the display surface OP and the reflecting surface S1 of the reflecting unit 102. That is, the ZX plane shows the state of observation with the optical pupil EP arranged so as to coincide with the Z axis). The reflection surface S1 is a concave mirror having a negative power, and the reflection angle from the reflection surface S1 of each light beam irradiated from the display surface OP varies. In the example shown in FIG. 14, the reflection angle from the reflection surface S1 of each light beam irradiated from the display surface OP is adjusted by the refractive optical element 1401 made of a convex lens. As a result, as indicated by reference numeral 1402, the curvature of the image plane observed at the optical pupil EP is corrected.
　また、図１５には、表示面ＯＰと反射部１０２の反射面Ｓ１の間に、屈折型光学素子１５０１を配置した場合の、反射面Ｓ１からの反射光を、光学系の中心（すなわち、Ｚ軸）からＸ方向にシフトした位置の光学瞳ＥＰで観察する様子を、ＺＸ平面で示している。反射面Ｓ１は、負のパワーを持つ凹面鏡であり、表示面ＯＰから照射される各光線の反射面Ｓ１からの反射角度はまちまちである。また、光学瞳ＥＰが光学系の中心からシフトしているため像面が傾く。これに対し、屈折型光学素子１５０１は、凸レンズ１５０１Ａと楔形１５０１Ｂを重ね合わせた形状を備えている。屈折型光学素子１５０１の凸レンズ１５０１Ａの部分によって、表示面ＯＰから照射される各光線の反射面Ｓ１からの反射角度が調整される。また、屈折型光学素子１５０１の楔形１５０１Ｂの部分によって、像面の傾きが補正される。この結果、参照番号１５０２で示すように、光学瞳ＥＰで観察される像面の湾曲と傾きは補正されている。 Further, in FIG. 15, the reflected light from the reflecting surface S1 when the refractive optical element 1501 is disposed between the display surface OP and the reflecting surface S1 of the reflecting unit 102 is the center of the optical system (that is, Z A state of observing with the optical pupil EP at a position shifted in the X direction from the axis) is shown on the ZX plane. The reflection surface S1 is a concave mirror having a negative power, and the reflection angle from the reflection surface S1 of each light beam irradiated from the display surface OP varies. Further, since the optical pupil EP is shifted from the center of the optical system, the image plane is inclined. On the other hand, the refractive optical element 1501 has a shape in which a convex lens 1501A and a wedge 1501B are overlapped. The reflection angle from the reflection surface S1 of each light beam irradiated from the display surface OP is adjusted by the convex lens 1501A portion of the refractive optical element 1501. Further, the inclination of the image plane is corrected by the wedge-shaped portion 1501B of the refractive optical element 1501. As a result, as indicated by reference numeral 1502, the curvature and inclination of the image plane observed with the optical pupil EP are corrected.
　図１６には、光学瞳ＥＰを光学系の中心（すなわち、Ｚ軸）に一致するように配置したときの像面の湾曲を補正するように構成された屈折型光学素子１４０１と、光学瞳ＥＰを光学系の中心（すなわち、Ｚ軸）からＸ方向にシフトしたときの像面の湾曲を補正するように構成された屈折型光学素子１５０１を重ね合わせて描いている。光学瞳ＥＰのサイズ拡大に対応するには、屈折型光学素子１４０１及び１５０１を合成した面形状とする必要があり、要するに図１０に示したような面形状になるということを理解できよう。 FIG. 16 shows a refractive optical element 1401 configured to correct curvature of the image plane when the optical pupil EP is arranged so as to coincide with the center of the optical system (that is, the Z axis), and the optical pupil EP. Is drawn by superimposing a refractive optical element 1501 configured to correct curvature of the image plane when shifted from the center of the optical system (that is, the Z axis) in the X direction. In order to cope with the enlargement of the size of the optical pupil EP, it is necessary to obtain a surface shape obtained by combining the refractive optical elements 1401 and 1501. In short, it can be understood that the surface shape is as shown in FIG.
　図５には、本明細書で開示する技術を適用した画像表示装置５００の他の構成例（横断面図）を模式的に示している。画像表示装置５００は、表示面ＯＰに画像を表示する表示部５０１と、表示面ＯＰから射出される光を光学瞳ＥＰの位置まで導く光学系を備え、表示面ＯＰの拡大虚像を観察者に観察させるように構成されている。光学系は、表示面ＯＰと光学瞳ＥＰとの間の光路中に配設された１面の反射面からなる反射部５０２と、表示面ＯＰと反射部５０２の反射面の間に配設された２つの屈折型光学素子５０３及び５０４で構成される。 FIG. 5 schematically shows another configuration example (cross-sectional view) of the image display device 500 to which the technology disclosed in this specification is applied. The image display apparatus 500 includes a display unit 501 that displays an image on the display surface OP, and an optical system that guides light emitted from the display surface OP to the position of the optical pupil EP, and provides an enlarged virtual image of the display surface OP to an observer. It is configured to be observed. The optical system is disposed between the reflection unit 502 including one reflection surface disposed in the optical path between the display surface OP and the optical pupil EP, and between the display surface OP and the reflection surface of the reflection unit 502. And two refractive optical elements 503 and 504.
　画像表示装置５００と図１～図３に示した画像表示装置１００との１つの相違点は、表示部５０１の表示面ＯＰと反射部５０２の反射面との角度θを広くしている点である。角度θを広くすると、屈折型光学素子５０３及び５０４が反射部５０２の反射面による反射光（拡大虚像）が光学瞳ＥＰに向かう光路から大きく外れるので、観察者の良好な視界を確保することができる。 One difference between the image display device 500 and the image display device 100 shown in FIGS. 1 to 3 is that the angle θ between the display surface OP of the display unit 501 and the reflection surface of the reflection unit 502 is widened. is there. When the angle θ is widened, the refraction type optical elements 503 and 504 largely deviate from the optical path toward the optical pupil EP because the reflected light (enlarged virtual image) by the reflecting surface of the reflecting portion 502 can secure a good field of view for the observer. it can.
　また、画像表示装置５００と図１～図３に示した画像表示装置１００との他の相違点は、２つの屈折型光学素子５０３及び５０４を備えている点である。図５に示すように、表示部５０１の表示面ＯＰと反射部５０２の反射面との角度θを広くすると、偏心による収差が大きくなり、単一の屈折型光学素子１０３だけで諸収差を補正することは困難となる。このため、図５に示すように、２つの屈折型光学素子５０３及び５０４（あるいは、３以上の屈折型光学素子）を用いて諸収差を補正することが好ましい。また、前述したように、複数の屈折型光学素子を、諸収差の補正用と拡大虚像の倍率用で使い分けるようにしてもよい。 Further, another difference between the image display device 500 and the image display device 100 shown in FIGS. 1 to 3 is that two refractive optical elements 503 and 504 are provided. As shown in FIG. 5, when the angle θ between the display surface OP of the display unit 501 and the reflection surface of the reflection unit 502 is widened, aberration due to decentering increases, and various aberrations are corrected only by the single refractive optical element 103. It will be difficult to do. For this reason, as shown in FIG. 5, it is preferable to correct various aberrations using two refractive optical elements 503 and 504 (or three or more refractive optical elements). Further, as described above, a plurality of refractive optical elements may be properly used for correcting various aberrations and for magnification of the magnified virtual image.
　図５に示す画像表示装置５００も、図１～図３に示した画像表示装置１００と同様に、（１）屈折型光学素子を用いた構成にすることで諸収差に対する感度の緩い光学系となり、装置の製造がし易くなる、（２）光学系が小型な構成となり、製品がコンパクトになる、（３）収差補正レンズとして屈折型光学素子を使用することで、高画角で光学瞳サイズを拡大でき、瞳をシフトさせても快適な視聴をすることができる、という利点がある。 Similar to the image display device 100 shown in FIGS. 1 to 3, the image display device 500 shown in FIG. 5 also becomes an optical system with a low sensitivity to various aberrations by using (1) a configuration using a refractive optical element. (2) The optical system becomes compact and the product becomes compact. (3) The optical pupil size can be increased at a high angle of view by using a refractive optical element as an aberration correction lens. There is an advantage that a comfortable viewing can be performed even if the pupil is shifted.
　以上、特定の実施形態を参照しながら、本明細書で開示する技術について詳細に説明してきた。しかしながら、本明細書で開示する技術の要旨を逸脱しない範囲で当業者が該実施形態の修正や代用を成し得ることは自明である。 As described above, the technology disclosed in this specification has been described in detail with reference to specific embodiments. However, it is obvious that those skilled in the art can make modifications and substitutions of the embodiments without departing from the scope of the technology disclosed in this specification.
　本明細書で開示する技術は、自動車のフロントガラスなど観察者の視界に情報を表示するヘッドアップディスプレイを始めとして、スマートフォンやタブレット端末、ゲーム機などの表示面の拡大虚像を観察者に観察させるさまざまなタイプの光学装置や画像表示装置に適用することができる。 The technology disclosed in this specification allows an observer to observe an enlarged virtual image on a display surface of a smartphone, a tablet terminal, a game machine, or the like, including a head-up display that displays information in the observer's field of view, such as a car windshield. The present invention can be applied to various types of optical devices and image display devices.
　要するに、例示という形態により本明細書で開示する技術について説明してきたのであり、本明細書の記載内容を限定的に解釈するべきではない。本明細書で開示する技術の要旨を判断するためには、特許請求の範囲を参酌すべきである。 In short, the technology disclosed in the present specification has been described in the form of examples, and the description content of the present specification should not be interpreted in a limited manner. In order to determine the gist of the technology disclosed in this specification, the claims should be taken into consideration.
　なお、本明細書の開示の技術は、以下のような構成をとることも可能である。
（１）表示面に表示された画像の虚像を光学瞳の位置で観察させる光学装置であって、
　前記表示面と前記光学瞳との間の光路中に配設された１つの反射面のみを持つ反射部と、
　前記表示面と前記反射面の間に配設された屈折型光学素子と、
を具備する光学装置。
（２）前記反射面は、前記表示面の中心と前記光学瞳の中心とを光学的に結ぶ光軸に対して偏心して配設される、
上記（１）に記載の光学装置。
（３）前記屈折型光学素子は、前記表示面の中心と前記光学瞳の中心とを光学的に結ぶ光軸に対して偏心して配設される、
上記（１）に記載の光学装置。
（４）前記反射面は、負のパワーを持ち、前記表示面に表示される画像を拡大する、
上記（１）に記載の光学装置。
（５）前記屈折型光学素子は、光が媒体中を透過して、スネルの法則により光を屈折させる作用を持つ素子からなる、
上記（１）に記載の光学装置。
（６）前記屈折型光学素子は、前記表示面から射出される各光線が前記反射面を経由して前記光学瞳に至るまでに発生する光路差に起因する諸収差を補正する、
上記（１）に記載の光学装置。
（７）前記屈折型光学素子は、前記表示面から射出される各光線が前記反射面を経由して前記光学瞳に至るまでの光路長を調整する面形状を有する、
上記（１）に記載の光学装置。
（８）前記屈折型光学素子は、前記表示面から射出される各光線が前記反射面によって反射される角度の相違に起因する前記虚像の歪曲を補正する、
上記（１）に記載の光学装置。
（９）前記屈折型光学素子は、前記表示面から射出される各光線を屈折させて、前記反射面への入射角度を調整する、
上記（１）に記載の光学装置。
（１０）前記屈折型光学素子のいずれか一方の面又は両面は、球面形状、非球面形状、アナモルフィック形状、又は自由曲面形状を有する、
上記（１）乃至（９）のいずれかに記載の光学装置。
（１１）前記屈折型光学素子の光軸に平行な方向に対する高さを表すＳａｇの２次微分は光軸との交点以外の領域で０になる点を持つ（すなわち、Ｓａｇの２次微分は原点以外の領域で符号が変わる）、
上記（１）に記載の光学装置。
（１２）複数の前記屈折型光学素子を備える、
上記（１）乃至（１０）のいずれかに記載の光学装置。
（１３）複数の前記屈折型光学素子の一部は前記諸収差又は歪曲を補正し、他の一部は前記虚像を拡大する、
上記（１２）に記載の光学装置。
（１４）画像を表示する表示面を有する表示部と、
　前記表示面と画像の虚像を観察する光学瞳との間の光路中に配設された１つの反射面のみを持つ反射部と、
　前記表示面と前記反射面の間に配設された屈折型光学素子と、
を具備する画像表示装置。 Note that the technology disclosed in the present specification can also be configured as follows.
(1) An optical device for observing a virtual image of an image displayed on a display surface at a position of an optical pupil,
A reflection part having only one reflection surface disposed in an optical path between the display surface and the optical pupil;
A refractive optical element disposed between the display surface and the reflective surface;
An optical device comprising:
(2) The reflecting surface is arranged eccentrically with respect to an optical axis that optically connects the center of the display surface and the center of the optical pupil.
The optical device according to (1) above.
(3) The refractive optical element is disposed eccentrically with respect to an optical axis that optically connects the center of the display surface and the center of the optical pupil.
The optical device according to (1) above.
(4) The reflecting surface has negative power and enlarges an image displayed on the display surface.
The optical device according to (1) above.
(5) The refractive optical element is composed of an element having a function of allowing light to pass through the medium and refracting the light according to Snell's law.
The optical device according to (1) above.
(6) The refractive optical element corrects various aberrations caused by optical path differences that occur until each light beam emitted from the display surface reaches the optical pupil via the reflective surface.
The optical device according to (1) above.
(7) The refractive optical element has a surface shape that adjusts an optical path length of each light beam emitted from the display surface to reach the optical pupil via the reflection surface.
The optical device according to (1) above.
(8) The refractive optical element corrects distortion of the virtual image due to a difference in angle at which each light beam emitted from the display surface is reflected by the reflection surface.
The optical device according to (1) above.
(9) The refractive optical element refracts each light beam emitted from the display surface and adjusts an incident angle on the reflection surface.
The optical device according to (1) above.
(10) Either one or both surfaces of the refractive optical element has a spherical shape, an aspherical shape, an anamorphic shape, or a free-form surface shape.
The optical device according to any one of (1) to (9) above.
(11) The second derivative of Sag representing the height of the refractive optical element with respect to the direction parallel to the optical axis has a point that becomes 0 in a region other than the intersection with the optical axis (that is, the second derivative of Sag is The sign changes in areas other than the origin)
The optical device according to (1) above.
(12) A plurality of the refractive optical elements are provided.
The optical device according to any one of (1) to (10) above.
(13) A part of the plurality of refractive optical elements corrects the aberrations or distortion, and the other part enlarges the virtual image.
The optical device according to (12) above.
(14) a display unit having a display surface for displaying an image;
A reflection part having only one reflection surface disposed in an optical path between the display surface and an optical pupil for observing a virtual image of the image;
A refractive optical element disposed between the display surface and the reflective surface;
An image display device comprising:
　１００…画像表示装置
　１０１…表示部、１０２…反射部、１０３…屈折型光学素子
　５００…画像表示装置
　５０１…表示部、５０２…反射部
　５０３、５０４…屈折型光学素子 DESCRIPTION OF SYMBOLS 100 ... Image display apparatus 101 ... Display part, 102 ... Reflection part, 103 ... Refraction type optical element 500 ... Image display apparatus 501 ... Display part, 502 ... Reflection part 503,504 ... Refraction type optical element

Claims (14)

  1. 　表示面に表示された画像の虚像を光学瞳の位置で観察させる光学装置であって、
    　前記表示面と前記光学瞳との間の光路中に配設された１つの反射面のみを持つ反射部と、
    　前記表示面と前記反射面の間に配設された屈折型光学素子と、
    を具備する光学装置。     An optical device for observing a virtual image of an image displayed on a display surface at a position of an optical pupil,
    A reflection part having only one reflection surface disposed in an optical path between the display surface and the optical pupil;
    A refractive optical element disposed between the display surface and the reflective surface;
    An optical device comprising:
  2. 　前記反射面は、前記表示面の中心と前記光学瞳の中心とを光学的に結ぶ光軸に対して偏心して配設される、
    請求項１に記載の光学装置。     The reflecting surface is arranged eccentrically with respect to an optical axis that optically connects the center of the display surface and the center of the optical pupil;
    The optical device according to claim 1.
  3. 　前記屈折型光学素子は、前記表示面の中心と前記光学瞳の中心とを光学的に結ぶ光軸に対して偏心して配設される、
    請求項１に記載の光学装置。     The refractive optical element is arranged eccentrically with respect to an optical axis that optically connects the center of the display surface and the center of the optical pupil.
    The optical device according to claim 1.
  4. 　前記反射面は、負のパワーを持ち、前記表示面に表示される画像を拡大する、
    請求項１に記載の光学装置。     The reflecting surface has negative power and enlarges an image displayed on the display surface;
    The optical device according to claim 1.
  5. 　前記屈折型光学素子は、光が媒体中を透過して、スネルの法則により光を屈折させる作用を持つ素子からなる、
    請求項１に記載の光学装置。     The refractive optical element is composed of an element having an action of light passing through the medium and refracting the light according to Snell's law.
    The optical device according to claim 1.
  6. 　前記屈折型光学素子は、前記表示面から射出される各光線が前記反射面を経由して前記光学瞳に至るまでに発生する光路差に起因する諸収差を補正する、
    請求項１に記載の光学装置。     The refractive optical element corrects various aberrations caused by optical path differences that occur until each light beam emitted from the display surface reaches the optical pupil via the reflection surface.
    The optical device according to claim 1.
  7. 　前記屈折型光学素子は、前記表示面から射出される各光線が前記反射面を経由して前記光学瞳に至るまでの光路長を調整する面形状を有する、
    請求項１に記載の光学装置。     The refractive optical element has a surface shape that adjusts the optical path length of each light beam emitted from the display surface to reach the optical pupil via the reflective surface.
    The optical device according to claim 1.
  8. 　前記屈折型光学素子は、前記表示面から射出される各光線が前記反射面によって反射される角度の相違に起因する前記虚像の歪曲を補正する、
    請求項１に記載の光学装置。     The refractive optical element corrects distortion of the virtual image due to a difference in angle at which each light beam emitted from the display surface is reflected by the reflecting surface;
    The optical device according to claim 1.
  9. 　前記屈折型光学素子は、前記表示面から射出される各光線を屈折させて、前記反射面への入射角度を調整する、
    請求項１に記載の光学装置。     The refractive optical element refracts each light beam emitted from the display surface and adjusts an incident angle on the reflecting surface;
    The optical device according to claim 1.
  10. 　前記屈折型光学素子のいずれか一方の面又は両面は、球面形状、非球面形状、アナモルフィック形状、又は自由曲面形状を有する、
    請求項１乃至９のいずれかに記載の光学装置。     Either one or both surfaces of the refractive optical element have a spherical shape, an aspherical shape, an anamorphic shape, or a free-form surface shape.
    The optical device according to claim 1.
  11. 　前記屈折型光学素子の光軸に平行な方向に対する高さを表すＳａｇの２次微分は光軸との交点以外の領域で０になる点を持つ（すなわち、Ｓａｇの２次微分は原点以外の領域で符号が変わる）、
    請求項１に記載の光学装置。     The second derivative of Sag representing the height of the refractive optical element with respect to the direction parallel to the optical axis has a point that becomes 0 in a region other than the intersection with the optical axis (that is, the second derivative of Sag is other than the origin). The sign changes in the region),
    The optical device according to claim 1.
  12. 　複数の前記屈折型光学素子を備える、
    請求項１乃至１０のいずれかに記載の光学装置。     Comprising a plurality of refractive optical elements,
    The optical device according to claim 1.
  13. 　複数の前記屈折型光学素子の一部は前記諸収差又は歪曲を補正し、他の一部は前記虚像を拡大する、
    請求項１２に記載の光学装置。     Some of the plurality of refractive optical elements correct the aberrations or distortion, and the other part enlarges the virtual image.
    The optical device according to claim 12.
  14. 　画像を表示する表示面を有する表示部と、
    　前記表示面と画像の虚像を観察する光学瞳との間の光路中に配設された１つの反射面のみを持つ反射部と、
    　前記表示面と前記反射面の間に配設された屈折型光学素子と、
    を具備する画像表示装置。     A display unit having a display surface for displaying an image;
    A reflection part having only one reflection surface disposed in an optical path between the display surface and an optical pupil for observing a virtual image of the image;
    A refractive optical element disposed between the display surface and the reflective surface;
    An image display device comprising:
PCT/JP2016/053174 2015-02-27 2016-02-03 Optical device and image display device WO2016136407A1 (en)

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