Virtual image display device and optical unit

Abstract

To provide a uniform backlight by a compact transmission type light source member.SOLUTION: The virtual image display device includes a transmissive OLED panel that transmits external light in a first state and emits backlight in a second state, a transmissive display member that faces the transmissive OLED panel, further transmits the external light transmitted through the transmissive OLED panel in the first state, and transmits the backlight emitted by the transmissive OLED panel and emits video light in the second state, and an imaging optical system that faces the transmissive OLED panel with the display member interposed therebetween, transmits at least a part of the external light in the first state, and forms an image of the video light in the second state.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a virtual image display device and an optical unit that enable the observation of a virtual image, and more particularly to a virtual image display device or the like that uses a transmissive OLED panel and a transmissive liquid crystal panel, and an optical unit. [Background technology]

[0002] A known see-through virtual image display device that enables viewing of the outside world includes a liquid crystal panel having an image display area and a transparent display area surrounding the image display area, and a light guide plate that guides backlight incident from a light source to an edge of the panel. The light guide plate has a light-emitting area that irradiates the image display area of ​​the liquid crystal panel with the backlight and a light-transmitting area that transmits ambient light (Patent Document 1). This virtual image display device is configured so that ambient light reaches the viewer through the light-transmitting area of ​​the light guide plate and the transparent display area of ​​the liquid crystal panel, and also so that ambient light reaches the viewer by passing through the light-emitting area of ​​the light guide plate and the image display area of ​​the liquid crystal panel during periods when backlight is not irradiated onto the image display area. This configuration achieves a see-through display in which image light and ambient light are superimposed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2016 / 056298 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above device, the light-emitting area of ​​the light guide plate is processed by forming dots, applying scattering material, etc., and ambient light passing through the image display area of ​​the liquid crystal panel passes through the processed light-emitting area, resulting in a decrease in see-through transmittance near the center of the field of view corresponding to the image display area. In order to achieve a see-through display with high see-through transmittance near the center of the field of view, a separate optical system with high see-through transmittance is required, which leads to an increase in size. [Means for solving the problem]

[0005] A virtual image display device according to one aspect of the present invention includes a transmissive OLED (Organic Light Emitting Diode) panel that transmits external light in a first state and emits backlight in a second state; a transmissive display element facing the transmissive OLED panel that further transmits the external light that has passed through the transmissive OLED panel in the first state and transmits the backlight emitted by the transmissive OLED panel in the second state to emit image light; and an imaging optical system facing the transmissive OLED panel across the display element that transmits at least a portion of the external light in the first state and forms an image from the image light in the second state. The transmissive OLED panel includes a first transmissive OLED element that emits light of a first color, and a second transmissive OLED element stacked on the first transmissive OLED element that emits light of a second color.

[0006] An optical unit according to one aspect of the present invention includes: a transmissive OLED panel that transmits external light in a first state and emits backlight in a second state; a transmissive display element that faces the transmissive OLED panel and further transmits the external light that has passed through the transmissive OLED panel in the first state and transmits the backlight emitted by the transmissive OLED panel in the second state to emit image light; and an imaging optical system that faces the transmissive OLED panel across the display element and transmits at least a portion of the external light in the first state and forms an image from the image light in the second state. The transmissive OLED panel includes a first transmissive OLED element that emits light of a first color, and a second transmissive OLED element that is stacked on the first transmissive OLED element and emits light of a second color. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 2 is an external front view illustrating a wearing state of the virtual image display device of the first embodiment. [Figure 2] FIG. 2 is a conceptual perspective view illustrating the structure of a display optical system. [Figure 3] FIG. 2 is a side cross-sectional view illustrating a light source member. [Figure 4] FIG. 2 is a side cross-sectional view illustrating a display device. [Figure 5] FIG. 10 is a diagram illustrating the state of light passing through the display. [Figure 6] FIG. 2 is a side cross-sectional view showing an optical unit of the display optical system. [Figure 7] FIG. 10 is a view of the optical unit as seen from another direction. [Figure 8] FIG. 1 is a conceptual perspective view illustrating the function of a polarized diffractive lens. [Figure 9] 4 is a timing chart illustrating a display operation by the display optical system. [Figure 10] FIG. 10 is a conceptual perspective view illustrating a transmissive liquid crystal panel according to a second embodiment. [Figure 11] FIG. 2 is a side cross-sectional view showing an optical unit of the display optical system. [Figure 12] 3A and 3B are a front view and a cross-sectional view illustrating the positional relationship and dimensions of a transmissive liquid crystal panel. [Figure 13] FIG. 4 is a cross-sectional view illustrating the positional relationship between a transmissive liquid crystal panel and a spacer. [Figure 14] FIG. 10 is a side cross-sectional view showing an optical unit of a display optical system according to a modified example. [Figure 15] FIG. 10 is a side cross-sectional view illustrating a display device according to a third embodiment. [Figure 16] FIG. 10 is a diagram illustrating the state of light passing through the display. [Figure 17] 4 is a timing chart illustrating a display operation by the display optical system. [Figure 18] FIG. 10 is a side cross-sectional view illustrating a light source member according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0008] [First embodiment] Hereinafter, a virtual image display device according to a first embodiment of the present invention will be described with reference to FIGS.

[0009] FIG. 1 is a front view illustrating a state in which a head-mounted display, i.e., a head-mounted display device 200, is worn. The head-mounted display device (hereinafter also referred to as HMD) 200 allows an observer or wearer US wearing it to recognize an image as a virtual image. In FIG. 1 and other figures, X, Y, and Z are Cartesian coordinate systems, with the +X direction corresponding to the lateral direction in which the eyes EY of the observer or wearer US wearing the HMD 200 are aligned, the +Y direction corresponding to the upward direction perpendicular to the lateral direction in which the eyes EY are aligned for the wearer US, and the +Z direction corresponding to the forward direction or front direction for the wearer US. The ±Y directions are parallel to the vertical axis or vertical direction.

[0010] The HMD 200 includes a first virtual image display device 100A for the right eye, a second virtual image display device 100B for the left eye, a pair of temples 100C supporting the virtual image display devices 100A and 100B, and a user terminal 90 serving as an information terminal. The first virtual image display device 100A includes a first display driver 102a disposed at the top and a first display optical system 103a covering the user's eyes. The second virtual image display device 100B includes a second display driver 102b disposed at the top and a second display optical system 103b covering the user's eyes. The HMD 200, which combines the first virtual image display device 100A and the second virtual image display device 100B, is also a virtual image display device in a broad sense. The pair of temples 100C are mounting members or support devices 106 worn on the head of the wearer US, and support the upper ends of the pair of display optical systems 103a and 103b via display drivers 102a and 102b, which are integrated in appearance. The pair of display drivers 102a and 102b is called a driver 102.

[0011] 2 is a conceptual perspective view illustrating the structure of the first display optical system 103a. The first display optical system 103a includes a plate-like display 40 that forms a two-dimensional image and emits corresponding image light ML, and a plate-like imaging optical system 50 that functions as a lens for the image light ML emitted from the display 40 to form a virtual image. In FIG. 2, the spacing between the components is partially enlarged to make it easier to understand the configuration of the first display optical system 103a.

[0012] The display 40 includes a light source member 10 including a first light source 10R that generates light of a first color, a second light source 10G that generates light of a second color, and a third light source 10B that generates light of a third color; a display element 20 that forms and emits image light ML; and a quarter-wave plate 23. The light source member 10 emits a backlight BLR of a first color, a backlight BLG of a second color, and a backlight BLG of a third color as backlight BL. The first, second, and third colors are selected so that the backlights BLR, BLG, and BLB are superimposed to form white light. The display 40 is driven and operated by a drive circuit 81 of a control device 80 incorporated in a first display drive unit 102a or a drive device 102. The display element 20 of the display 40 is disposed close to the eye EY with an imaging optical system 50 sandwiched therebetween, enabling observation of a virtual image formed by image light ML and a see-through view of the outside world. In the first display optical system 103a, the distance between the eye EY and the imaging optical system 50 in the direction of the optical axis AX is, for example, about 10 mm to 20 mm. Also, the distance between the transmissive liquid crystal panel 22 of the display 40 and the imaging optical system 50 in the direction of the optical axis AX is, for example, about 5 mm to 25 mm.

[0013] The display element 20 is a plate-like member extending along an XY plane perpendicular to the optical axis AX, and includes, in order from the outside, a first polarizing plate 21A, a transmissive liquid crystal panel 22, and a second polarizing plate 21B. The display element 20 has a structure in which the polarizing plates 21A and 21B and the transmissive liquid crystal panel 22 are stacked and integrated by a frame (not shown). The first polarizing plate 21A and the transmissive liquid crystal panel 22 are arranged in close proximity, with a predetermined distance or less between them. The transmissive liquid crystal panel 22 and the second polarizing plate 21B are also arranged in close proximity, with a predetermined distance or less between them. The transmissive liquid crystal panel 22 is an imager that forms, in a time-division manner, a first image light of a first color component, a second image light of a second color component, and a third image light of a third color component, which constitute the image light ML. The transmissive liquid crystal panel 22 includes a plurality of pixels arranged in a matrix along the XY plane.

[0014] The imaging optical system 50 is disposed on the face side, i.e., the -Z side, of the display 40 or the display element 20, and covers the eyes. The imaging optical system 50 is a plate-shaped member extending along the XY plane, and includes, in order from the outside, a first polarizing diffractive lens 51, a switching half-wave plate 55, and a second polarizing diffractive lens 52. The imaging optical system 50 has a structure in which its constituent optical elements, namely the first polarizing diffractive lens 51, the switching half-wave plate 55, and the second polarizing diffractive lens 52, are arranged parallel to one another and adjacent to one another, and are integrated by a frame (not shown). This integration stabilizes the optical performance of the imaging optical system 50 and enables the imaging optical system 50 to be made thinner. Note that, including cases in which other optical elements are disposed between the first polarizing diffractive lens 51 and the second polarizing diffractive lens 52 in addition to the switching half-wave plate 55, these can be integrated by directly fixing them with an adhesive, or by closely adhering them to each other and fixing them at their peripheries. Furthermore, the distance between the first polarizing diffractive lens 51 and the second polarizing diffractive lens 52 can be adjusted before they are integrated. The imaging optical system 50 is a dynamic optical element whose function changes depending on the state of the switching half-wave plate 55. The imaging optical system 50 functions as a lens for the image light ML emitted from the display element 20. In other words, the imaging optical system 50 comprehensively forms an image of multiple pixels included in the transmissive liquid crystal panel 22, making it possible to observe the image formed on the transmissive liquid crystal panel 22 as a virtual image. On the other hand, the imaging optical system 50 functions as a parallel plate for the external light OL passing through the display element 20. In other words, the external light OL is observed as a direct-view image by passing through the display element 20 in a straight line.

[0015] The second display optical system 103b is optically identical to the first display optical system 103a, or is a left-right inversion of the first display optical system 103a, and a detailed description thereof will be omitted.

[0016] In the first virtual image display device 100A, the optical device excluding the control device 80 is called the optical unit 100. In the second virtual image display device 100B, the optical device excluding the control device 80 is called the optical unit 100.

[0017] The quarter-wave plate 23 has a principal axis, for example, halfway between the X and Y directions, and converts the image light ML and the external light OL from linearly polarized light to circularly polarized light. Here, when focusing on the vibration of the electric field component or magnetic field component of the image light ML, the vibration direction rotates at the frequency of the image light ML in a plane perpendicular to the light propagation direction, and the amplitude is constant regardless of the direction. Right-handed circularly polarized light is light in which the vibration direction of the electric field component rotates clockwise as seen by an observer standing facing the direction of the light beam, and left-handed circularly polarized light is light in which the vibration direction rotates counterclockwise. However, in this specification, if the image light ML mainly contains right-handed circularly polarized light, even if it also contains linearly polarized light in a specific direction, such image light ML is considered to be right-handed circularly polarized light RCP. Similarly, if the image light ML mainly contains left-handed circularly polarized light, such image light ML is considered to be left-handed circularly polarized light LCP. In this specification, right-handed circularly polarized RCP is also referred to as right-handed circularly polarized RCP, and left-handed circularly polarized LCP is also referred to as left-handed circularly polarized LCP.

[0018] Fig. 3 is a side cross-sectional view illustrating a light source member 10 as a transmissive OLED panel. The first light source 10R, the first adhesive layer 1081, the second light source 10G, the second adhesive layer 1082, the third light source 10B, and the cover member 109 included in the light source member 10 in Fig. 3 are stacked in this order in the -Z direction of a Cartesian coordinate system. As shown in Fig. 2, the -Z direction is the direction in which external light OL enters the light source member 10 from the outside, passes through the light source member 10, and then travels toward the display element 20, the imaging optical system 50, and both eyes EY of the wearer US.

[0019] 3, first light source 10R includes a first transmissive OLED element that emits a first color light to first backlight BLR. First transmissive OLED element 10R includes first transparent substrate 101R, first transparent anode 102R, first hole transport layer 103R, first light-emitting layer 104R, first electron transport layer 105R, first transparent cathode 106R, and first sealing layer 107R, which are stacked in this order in the −Z direction of a Cartesian coordinate system.

[0020] When an appropriate voltage is applied between the first transparent anode 102R and the first transparent cathode 106R, the first transmissive OLED element emits light of a first color from the first light-emitting layer 104R as the first backlight BLR. The first wavelength of the first backlight BLR corresponds to, for example, red and may be in the range of 600 nm to 640 nm, more preferably in the range of 610 nm to 630 nm.

[0021] Similarly, second light source 10G includes a second transmissive OLED element that emits second backlight BLG as light of a second color. The second transmissive OLED element includes second transparent substrate 101G, second transparent anode 102G, second hole transport layer 103G, second light-emitting layer 104G, second electron transport layer 105G, second transparent cathode 106G, and second sealing layer 107G, which are stacked in this order in the −Z direction of a Cartesian coordinate system.

[0022] When an appropriate voltage is applied between the second transparent anode 102G and the second transparent cathode 106G, the second transmissive OLED element emits light of a second color from the second light-emitting layer 104G as the second backlight BLG. The second wavelength of the second backlight BLG corresponds to, for example, green and may be in the range of 500 nm to 550 nm, more preferably in the range of 520 nm to 540 nm.

[0023] Furthermore, the third light source 10B includes a third transmissive OLED element that emits a third backlight BLB as light of a third color. The third transmissive OLED element includes a third transparent substrate 101B, a third transparent anode 102B, a third hole transport layer 103B, a third light-emitting layer 104B, a third electron transport layer 105B, a third transparent cathode 106B, and a third sealing layer 107B that are stacked in this order in the −Z direction of a Cartesian coordinate system.

[0024] When an appropriate voltage is applied between the third transparent anode 102B and the third transparent cathode 106B, the third transmissive OLED element emits a third color light from the third light-emitting layer 104B as the third backlight BLB. The second wavelength of the third backlight BLB corresponds to, for example, blue and may be in the range of 450 nm to 480 nm, more preferably in the range of 450 nm to 460 nm.

[0025] Each of the first light-emitting layer 104R, the second light-emitting layer 104G, and the third light-emitting layer 104B may have a single light-emitting element or a plurality of light-emitting elements arranged in a mesh pattern on the XY plane. In this embodiment, a configuration in which each of the light-emitting layers 104R, 104G, and 104B has a single light-emitting element will be described.

[0026] The first transmissive OLED element, the second transmissive OLED element, and the third transmissive OLED element are bonded together with an adhesive such as a resin. More specifically, a first adhesive layer 1081 is provided between a first sealing layer 107R of the first transmissive OLED element and a second transparent substrate 101G of the second transmissive OLED element, and the adhesive of the first adhesive layer 1081 is filled between the +Z direction surface of the first sealing layer 107R and the −Z direction surface of the second transparent substrate 101G. Similarly, a second adhesive layer 1082 is provided between a second sealing layer 107G of the second transmissive OLED element and a third transparent substrate 101B of the third transmissive OLED element, and the adhesive of the second adhesive layer 1082 is filled between the +Z direction surface of the second sealing layer 107G and the −Z direction surface of the third transparent substrate 101B. By filling the gap between the three transmissive OLED elements with adhesive, it is possible to obtain a higher transmittance for the light source member 10 as a whole, at least in the wavelength band of visible light, compared to when an air layer is provided between the three transmissive OLED elements.

[0027] A cover member 109 for protecting the third transmissive OLED element is provided on the +Z direction surface of third sealing layer 107B of the third transmissive OLED element. Meanwhile, a second transmissive OLED element is bonded to the +Z direction surface of first sealing layer 107R of the first transmissive OLED element, so a cover member for protecting the first transmissive OLED element is omitted. Similarly, a third transmissive OLED element is bonded to the +Z direction surface of second sealing layer 107G of the second transmissive OLED element, so a cover member for protecting the second transmissive OLED element is omitted. In this way, by integrating the three transmissive OLED elements, two cover members can be omitted. As a result, the light source member 10 can be made thinner than when the cover members are not omitted.

[0028] At least a portion of the first backlight BLR emitted by the first light-emitting layer 104R of the first light source 10R travels in the -Z direction, passes through the second light source 10G, the third light source 10B, and the cover member 109, and travels toward the display element 20, the imaging optical system 50, and the eyes EY of the wearer US. Similarly, at least a portion of the second backlight BLG emitted by the second light-emitting layer 104G of the second light source 10G travels in the -Z direction, passes through the third light source 10B and the cover member 109, and travels toward the display element 20, the imaging optical system 50, and the eyes EY of the wearer US. Furthermore, at least a portion of the third backlight BLB emitted by the third light-emitting layer 104B of the third light source 10B travels in the -Z direction, passes through the cover member 109, and travels toward the display element 20, the imaging optical system 50, and the eyes EY of the wearer US. Note that another portion of the first backlight BLR may leak out of the light source member 10 in the +Z direction. Similarly, another portion of the second backlight BLG may leak out of the light source member 10 in the +Z direction, pass through the first light source 10R, and leak out of the light source member 10. Furthermore, another portion of the third backlight BLB may leak out of the light source member 10 in the +Z direction, pass through the second light source 10G and the first light source 10R, and leak out of the light source member 10. However, the light leaking out of the light source member 10 in this manner does not pass through the transmissive liquid crystal panel 22, and therefore the image formed by the transmissive liquid crystal panel 22 does not leak out of the light source member 10.

[0029] In the example shown in FIG. 3 , among the three transmissive OLED elements included in the light source member 10, the third transmissive OLED element emitting the third backlight BLB corresponding to blue is positioned closest to the display element 20. Similarly, the first transmissive OLED element emitting the first backlight BLR corresponding to red is positioned farthest from the display element 20, and the second transmissive OLED element emitting the second backlight BLG corresponding to green is positioned in an intermediate position. These arrangements are merely examples and do not limit the present embodiment. However, the light-emitting layers 104R, 104G, and 104B, which are organic layers included in the OLED elements, relatively easily absorb light with wavelengths corresponding to blue. Therefore, it is preferable to position each transmissive OLED element so that light emitted from the third transmissive OLED element does not pass through the first transmissive OLED element and the second transmissive OLED element as much as possible. As an example, among the three transmissive OLED elements included in the light source member 10, the third transmissive OLED element may be positioned closest to the display element 20.

[0030] Furthermore, in order to efficiently extract the first backlight BLR, second backlight BLG, and third backlight BLB emitted from the respective transmissive OLED elements to the outside of the light source member 10, the thicknesses of the hole transport layers 103R, 103G, and 103B and the electron transport layers 105R, 105G, and 105B included in the light source member 10 may be set as follows: That is, the thicknesses of the hole transport layers 103R, 103G, and 103B and the electron transport layers 105R, 105G, and 105B are set thicker in the first transmissive OLED element, thinner in the third transmissive OLED element, and intermediate in the second transmissive OLED element. As a more specific example, the thickness of the first hole transport layer 103R is set to 106 nm, the thickness of the second hole transport layer 103G is set to 75 nm, and the thickness of the third hole transport layer 103B is set to 50 nm. The thickness of the first electron transport layer 105R is set to 66 nm, the thickness of the second electron transport layer 105G is set to 48 nm, and the thickness of the third electron transport layer 105B is set to 33 nm. The thicknesses of the first light-emitting layer 104R, the second light-emitting layer 104G, and the third light-emitting layer 104B are each set to 30 nm. In this case, the total thickness of the first hole transport layer 103R, the first light-emitting layer 104R, and the first electron transport layer 105R is 202 nm. Similarly, the total thickness of the second hole transport layer 103G, the second light-emitting layer 104G, and the second electron transport layer 105G is 153 nm. The total thickness of the third hole transport layer 103B, the third light-emitting layer 104B, and the third electron transport layer 105B is 113 nm.

[0031] Fig. 4 is a conceptual enlarged cross-sectional view illustrating the structure of the display device 40. Referring to Fig. 4, the light source member 10 generates three color backlights BLR, BLG, and BLB as the backlight BL in a time-division manner, and supplies any one of the three color backlights BLR, BLG, and BLB to the transmissive liquid crystal panel 22 of the display element 20 at a time.

[0032] The display element 20 is disposed on the face side, i.e., the -Z side, facing the light source member 10 and the first polarizing plate 21A. The display element 20 includes a transmissive liquid crystal panel 22 and a pair of polarizing plates 21A and 21B sandwiching the transmissive liquid crystal panel 22. In this case, the display element 20 is a modulation element made of, for example, an IPS (in-plane switching) type liquid crystal and operates in units of pixels PX. The pixels PX do not have a filter and are colorless. The display element 20 does not rotate the polarization direction of incident light when no electric field is applied, but rotates the polarization direction of incident light when an electric field is applied. In this case, the pair of polarizing plates 21A and 21B are absorption-type polarizing elements and are disposed so that their polarization directions intersect, more specifically, are perpendicular to each other. The display element 20 can switch ON and OFF in units of pixels PX in response to a drive signal from a drive circuit 81, allowing incident light to partially pass through at any gradation between ON and OFF. For this reason, the transmissive liquid crystal panel 22 includes not only a liquid crystal layer 31, a common electrode 32, pixel electrodes 33, and a black matrix 35, but also scanning lines, signal lines, switch elements, etc. (not shown). For higher definition, the transmissive liquid crystal panel 22 is preferably produced as an HTPS (High-Temperature Poly-Silicon) panel.

[0033] The display element 20 or the transmissive liquid crystal panel 22 may rotate the polarization direction of incident light when no electric field is applied, but not when an electric field is applied. In this case, the pair of polarizing plates 21A and 21B are arranged so that the polarization directions are parallel to each other.

[0034] The quarter-wave plate 23 has a principal axis, for example, midway between the X and Y directions, and converts the image light ML and the external light OL (see FIG. 2 ) from linearly polarized light to circularly polarized light. Here, when focusing on the vibration of the electric field component or magnetic field component of the image light ML, the vibration direction rotates at the frequency of the image light ML in a plane perpendicular to the light propagation direction, and the amplitude is constant regardless of the direction. Right-handed circularly polarized light is light in which the vibration direction of the electric field component rotates clockwise as seen by an observer standing facing the direction in which the light beam propagates, and left-handed circularly polarized light is light in which the vibration direction rotates counterclockwise. However, in this specification, if the image light ML mainly contains right-handed circularly polarized light, even if it also contains linearly polarized light in a specific direction, then such image light ML is considered to be right-handed circularly polarized light RCP. Similarly, if the image light ML mainly contains left-handed circularly polarized light, then such image light ML is considered to be left-handed circularly polarized light LCP. In this specification, right-handed circularly polarized RCP is also referred to as right-handed circularly polarized RCP, and left-handed circularly polarized LCP is also referred to as left-handed circularly polarized LCP.

[0035] Fig. 5 is a diagram illustrating the state of light passing through the display 40. In Fig. 5, a first area AR1 indicates a case where the first display optical system 103a is in an image observation period and the display 40 is in a display state, and a second area AR2 indicates a case where the first display optical system 103a is in an ambient light observation period and the display 40 is in a non-display state.

[0036] 5, when the display device 40 is in a display state during an image observation period, one of the light-emitting layers 104R, 104G, and 104B shown in FIG. 3 of the light source member 10 selectively emits light in response to a control signal from the control device 80 shown in FIG. 2, and at least a portion of one of the light-emitting layers BLR, BLG, and BLG of the backlight BL is emitted toward the display element 20. The backlight BL (BLR, BLG, and BLG) illuminates the transmissive liquid crystal panel 22 as second polarized light P2, which is horizontally polarized or horizontally polarized light, via the first polarizer 21A of the display element 20. In other words, each colorless pixel PX constituting the display element 20 is illuminated. The image light ML that has passed through the transmissive liquid crystal panel 22 is obtained by rotating the polarization plane of the backlight BL (BLR, BLG, and BLG) in response to a drive signal, and only the first polarized light P1, which is vertically polarized or vertically polarized light, is emitted via the second polarizer 21B. The image light ML emitted from each pixel PX of the display element 20 passes through the quarter-wave plate 23 and is converted from the first polarized light P1 into right-handed circularly polarized light RCP.

[0037] On the other hand, when the display 40 is in a non-display state during the external light observation period, the light source member 10 is set to a non-emitting state, i.e., an extinguished state. At this timing, external light OL is incident on the display element 20. At this time, each pixel PX of the display element 20 operates, for example, in a normally-off mode and is set to a maximum transmittance state by a drive signal, and the second polarized light P2 of the external light OL incident on each pixel PX of the display element 20 travels straight through the display element 20, i.e., the pixel PX, and is converted into the first polarized light P1. The external light OL emitted from each pixel PX of the display element 20 passes through the quarter-wave plate 23 and is converted from the first polarized light P1 into right-handed circularly polarized light RCP.

[0038] Fig. 6 is a side cross-sectional view showing the optical unit 100 of the display optical systems 103a and 103b, and Fig. 7 is a view of the optical unit 100 seen from another direction. In Fig. 7, the first region BR1 is a perspective view of the optical unit 100, and the second region BR2 is a rear view of the optical unit 100.

[0039] The optical unit 100 comprises a display 40 that emits image light ML and transmits external light OL, an imaging optical system 50 that functions as a positive lens or collimator with positive power for the image light ML, and a support member 101 that fixes these relative to one another.

[0040] In the imaging optical system 50, the first polarizing diffractive lens 51 functions alone as a positive lens when predetermined circularly polarized light is incident, and the second polarizing diffractive lens 52 also functions alone as a positive lens when predetermined circularly polarized light is incident. The switching half-wave plate 55 can be switched between an ON state and an OFF state, and when the switching half-wave plate 55 is in the ON state, it causes the polarizing diffractive lenses 51 and 52 to both function as positive lenses, and when the switching half-wave plate 55 is in the OFF state, it cancels out the powers of the polarizing diffractive lenses 51 and 52 and causes them to function like parallel flat plate glass.

[0041] FIG. 8 is a conceptual perspective view illustrating the functions of the first polarized diffractive lens 51 and the second polarized diffractive lens 52. In FIG. 8, the first region CR1 shows a first operational example of the first type of polarized diffractive lens GP1, and the second region CR2 shows a second operational example of the first type of polarized diffractive lens GP1. In FIG. 8, the third region CR3 shows a first operational example of the second type of polarized diffractive lens GP2, and the fourth region CR4 shows a second operational example of the second type of polarized diffractive lens GP2. The first polarized diffractive lens 51 and the second polarized diffractive lens 52 shown in FIG. 8 are the first type of polarized diffractive lens GP1.

[0042] When collimated right-handed circularly polarized light RCP, such as light ray L1 shown by the solid line, is incident on the polarized diffractive lens GP1 from the left side of the drawing, it converts the right-handed circularly polarized light RCP into left-handed circularly polarized light LCP and converges it to focus at the focal point FP. When collimated left-handed circularly polarized light LCP, such as light ray L1 shown by the solid line, is incident on the polarized diffractive lens GP1, it converts the left-handed circularly polarized light LCP into right-handed circularly polarized light RCP and diverges it. When right-handed circularly polarized light RCP diverging from the focal point FP' on the left side of the drawing, such as light ray L2 shown by the dashed-dot line, is incident on the polarized diffractive lens GP1, it converts the right-handed circularly polarized light RCP into left-handed circularly polarized light LCP and collimates it. In other words, the polarized diffractive lens GP1 functions like a positive lens with a predetermined focal length for right-handed circularly polarized light RCP, reversing the direction of polarization rotation. The polarized diffractive lens GP1 also functions like a negative lens with the same absolute focal length for left-handed circularly polarized light LCP, reversing the direction of polarization rotation. In other words, the polarized diffractive lens GP1 is an optical element that has a positive power for right-handed circularly polarized light RCP and a negative power for left-handed circularly polarized light LCP.

[0043] When collimated right-handed circularly polarized light RCP, such as light ray L1 shown by a solid line, enters the polarized diffractive lens GP2 from the left side of the drawing, it converts the right-handed circularly polarized light RCP into left-handed circularly polarized light LCP and diverges it. When collimated left-handed circularly polarized light LCP, such as light ray L1 shown by a solid line, enters the polarized diffractive lens GP2 from the left side of the drawing, it converts the left-handed circularly polarized light LCP into right-handed circularly polarized light RCP and converges the light to focus at the focal point FP. In other words, the polarized diffractive lens GP2 functions like a positive lens with a predetermined focal length for left-handed circularly polarized light LCP, reversing the direction of polarization rotation. Furthermore, the polarized diffractive lens GP2 functions like a negative lens with the same absolute focal length for right-handed circularly polarized light RCP, reversing the direction of polarization rotation. In other words, the polarized diffractive lens GP2 is an optical element that has negative power for right-handed circularly polarized light RCP and positive power for left-handed circularly polarized light LCP.

[0044] The polarized diffractive lenses GP1 and GP2 have a refractive index anisotropy distribution, which is grasped in a plane by a number of annular zones centered on the optical axis AX, and function as a diffractive lens according to the refractive index anisotropy distribution and the polarization state of the incident light. Specifically, when the polarized diffractive lenses GP1 and GP2 have a refractive index anisotropy distribution in which the orientation of the optical axis rotates (actually repeating in the range of 0 to π) with increasing distance from the optical axis AX in two directions that are perpendicular to the central optical axis AX and perpendicular to each other, a geometric phase is formed in the specific circularly polarized light incident thereon, and the circularly polarized light is diffracted at a diffraction angle that reflects the periodic length of the rotation of the optical axis in each direction, and the polarization state is reversed. As a whole, the polarized diffractive lens causes diffraction corresponding to the power formed by the lens shape for specific circularly polarized light, and reverses the state of circular polarization before and after passing through, for example, from right-handed circularly polarized light to left-handed circularly polarized light.

[0045] Although not shown, the polarized diffractive lenses GP1 and GP2 are each formed by forming a thin liquid crystal-containing material layer on a transparent substrate, and are generally thin and plate-like. The liquid crystal-containing material layer contains a predetermined liquid crystal material. The orientation axes of the liquid crystal molecules are aligned parallel to, for example, the X direction in the region near the optical axis AX to form a desired geometric phase. Furthermore, the orientation axes of the liquid crystal molecules gradually rotate within the XY plane as they move away from the optical axis AX, i.e., depending on the distance or radius from the optical axis AX. In other words, the rotation angle of the orientation axes of the liquid crystal molecules increases with the distance from the optical axis AX, and this cycle is repeated periodically. In the liquid crystal compound layer, the orientation axes of the liquid crystal molecules are aligned, for example, with a constant orientation in the Z direction parallel to the optical axis AX. Note that the direction of increasing the rotation angle of the orientation axes of the liquid crystal molecules is reversed between the polarized diffractive lenses GP1 and GP2. The polarized diffractive lenses GP1 and GP2 are manufactured, for example, by coating a substrate with a liquid crystal-containing material film, which is a mixture of a liquid crystal material and a UV-curable organic material layer, and then two-dimensionally scanning the liquid crystal-containing material film with UV laser light of a specific polarization state to adjust the alignment axis of the liquid crystal molecules and cure the organic material layer. This allows the alignment axis of the liquid crystal molecules in the liquid crystal-containing material layer to be controlled and fixed three-dimensionally, resulting in a liquid crystal compound layer in which the rotation angle of the alignment axis increases with distance from the optical axis AX as described above. Such a polarized diffractive lens GP1 itself is a known technology, such as a polarization-dependent liquid crystal Fresnel lens (see, for example, Kohei Noda, et al., Applied Optics, February 10, 2017, Vol. 56, No. 5: 1302).

[0046] The polarized diffraction lens GP1 and the polarized diffraction lens GP2 do not need to be separate entities; simply rotating the polarized diffraction lens GP1 180° around the Y axis and flipping it over will result in the polarized diffraction lens GP2. In other words, by swapping the polarized diffraction lenses GP1 and GP2, they can function as both positive and negative lenses for the same circularly polarized light. This is because, in the polarized diffraction lenses GP1 and GP2, the alignment axes of the liquid crystal molecules are increased so that they rotate in a specific direction depending on the distance from the optical axis AX, as described above. Therefore, the rotation directions relative to the absolute values ​​of the distances in the ±X directions perpendicular to the optical axis AX, for example, are the same. When each of the polarized diffraction lenses GP1 and GP2 is viewed from the back, the rotation directions of the alignment axes are reversed.

[0047] The focal lengths of the polarized diffractive lenses GP1 and GP2 can be increased or decreased depending on the manufacturing method and liquid crystal material. In the liquid crystal compound layer, for example, when increasing the rotation angle of the alignment axis of the liquid crystal molecules with increasing distance from the optical axis AX, the absolute value of the positive or negative power of the polarized diffractive lenses GP1 and GP2 can be increased by increasing the rate of increase in the rotation angle relative to the distance or radius from the optical axis AX, i.e., by reducing the rotation period of the alignment axis. When passing through the polarized diffractive lenses GP1 and GP2, the loss of circularly polarized light L1 is close to zero, and the polarized diffractive lenses GP1 and GP2 exhibit almost 100% transmittance.

[0048] When linearly polarized light is incident on the polarized diffractive lens GP1, the right-handed circularly polarized light (RCP) and the left-handed circularly polarized light (LCP) behave differently. The right-handed circularly polarized light (RCP) component is focused after passing through the polarized diffractive lens GP1, while the left-handed circularly polarized light (LCP) component is diverged after passing through the polarized diffractive lens GP1, and the rotation direction of each polarization is reversed.

[0049] 6, the switching half-wave plate 55 is a device that performs a switching operation in response to a drive signal from the drive circuit 81 shown in FIG. 2. Depending on the orientation direction of the liquid crystal, the switching half-wave plate 55 switches the polarization state of incident light from right-handed circularly polarized light (RCP) to left-handed circularly polarized light (LCP) and passes the light, or passes the light as right-handed circularly polarized light (LCP). That is, the switching half-wave plate 55 switches between an ON state, which is a first state in which the image light ML that has passed through the first polarizing diffractive lens 51 is converted from left-handed circularly polarized light (LCP), which is the second circularly polarized light, back to right-handed circularly polarized light (LCP), which is the first circularly polarized light, and an OFF state, which is a second state in which the image light ML that has passed through the first polarizing diffractive lens 51 is passed as left-handed circularly polarized light (LCP), which is the second circularly polarized light. The switching half-wave plate 55 includes a liquid crystal layer 55a sandwiched between a pair of substrates 55b and 55c with a transparent electrode layer (not shown) interposed therebetween. Liquid crystal layer 55a is, for example, an IPS (in-plane switching) type liquid crystal, which, when an electric field is applied, causes switching half-wave plate 55 to function as an optical element equivalent to a half-wave plate with its major axis or fast axis set in a specific direction (for example, halfway between the X and Y directions), and causes switching half-wave plate 55 to function as an isotropic parallel plate when no electric field is applied. Switching half-wave plate 55 switches between the ON and OFF states over the entire surface, rather than on a pixel-by-pixel basis.

[0050] 8, and when the image light ML and external light OL incident from the display 40 are right-handed circularly polarized light RCP, the first polarized diffractive lens 51 functions as an optical element having positive power with respect to the image light ML and external light OL, reducing the divergence of the image light ML and external light OL while reversing the direction of polarization rotation to convert them to left-handed circularly polarized light LCP. The image light ML and external light OL that have passed through the first polarized diffractive lens 51 are incident on the switching half-wave plate 55 in the state of left-handed circularly polarized light LCP.

[0051] The switching half-wave plate 55 is in the ON state during the image observation period, that is, when the image light ML is incident, and is in the OFF state during the ambient light observation period, that is, when the ambient light OL is incident.

[0052] During the image observation period, the switching half-wave plate 55, in the ON state, converts the image light ML incident thereon from left-handed circularly polarized light (LCP) to right-handed circularly polarized light (RCP). However, unlike a parallel plate, the image light ML passes through without substantially converging, and is incident on the second polarizing diffractive lens 52. The second polarizing diffractive lens 52 is the polarizing diffractive lens GP1 shown in FIG. 8. When the image light ML passing through the switching half-wave plate 55 is right-handed circularly polarized light (RCP), the second polarizing diffractive lens 52 functions as an optical element with positive power for the image light ML, reducing the divergence of the image light ML and reversing the direction of polarization rotation to convert it to left-handed circularly polarized light (LCP). In this case, the absolute value of the power of the first polarizing diffractive lens 51 and the absolute value of the power of the second polarizing diffractive lens 52 are set to be equal, and the composite focal length of both polarizing diffractive lenses 51 and 52 is approximately equivalent to the composite focal length of two adjacently arranged thin convex lenses. When the combined focal length of both polarizing diffractive lenses 51, 52 is equal to the distance from the midpoint between both polarizing diffractive lenses 51, 52 to display surface 11d of display 40, imaging optical system 50 functions as a collimator, collimating and focusing image light ML at pupil position PP. Although Fig. 5 shows only the chief ray of image light ML from display surface 11d, it can be seen from Figs. 6 and 7 that image light ML from a diagonal position on display surface 11d passes through pupil position PP.

[0053] On the other hand, during the external light observation period, the switching half-wave plate 55 in the OFF state maintains the external light OL incident thereon as left-handed circularly polarized light (LCP) and causes it to enter the second polarizing diffractive lens 52. The second polarizing diffractive lens 52 is the polarizing diffractive lens GP1 shown in FIG. 8. When the external light OL passing through the switching half-wave plate 55 is left-handed circularly polarized light (LCP), the second polarizing diffractive lens 52 functions as an optical element with negative power with respect to the external light OL, reducing the convergence of the external light OL while reversing the direction of polarization rotation to convert it to right-handed circularly polarized light (RCP). In this case, the two polarizing diffractive lenses 51 and 52 are positioned close to each other and are set so that the absolute values ​​of their powers are equal, and the composite focal length of the two polarizing diffractive lenses 51 and 52 is infinity. When the combined focal length of the polarized diffraction lenses 51, 52 is infinity, the imaging optical system 50 functions as equivalent to a parallel plate, which is an optical system with approximately zero power, and causes the external light OL to travel in a substantially straight line without exerting any imaging effect such as focusing, thereby enabling the external light OL to be observed with the naked eye.

[0054] As described above, during the image observation period, the imaging optical system 50 has positive power due to the switching half-wave plate 55 in the ON state, making it possible to observe the image light ML, and during the external light observation period, the imaging optical system 50 has substantially zero power due to the switching half-wave plate 55 in the OFF state, making it possible to observe the external light OL. In other words, the virtual image display devices 100A, 100B or the display optical systems 103a, 103b that perform such display enable a see-through display in which the image light ML and the external light OL are superimposed in a time-division manner.

[0055] 9 is a timing chart illustrating the display operation of the display optical systems 103a and 103b. The horizontal axis represents time, and from top to bottom, the diagram shows a blinking signal SS1 from the first light source 10R of a first color (e.g., red, R), a first drive signal SM1 for displaying the first color component that is applied to the transmissive liquid crystal panel 22, a blinking signal SS2 from the second light source 10G of a second color (e.g., green, G), a second drive signal SM2 for displaying the second color component that is applied to the transmissive liquid crystal panel 22, a blinking signal SS3 from the third light source 10B of a third color (e.g., blue, B), a third drive signal SM3 for displaying the third color component that is applied to the transmissive liquid crystal panel 22, and an on / off signal SW for the switching half-wave plate (½λ) 55. The operation of the first virtual image display device 100A includes, in each frame, a first subframe ZR that is a subframe for observing a first color image, a second subframe ZG that is a subframe for observing a second color image, a third subframe ZB that is a subframe for observing a third color image, and a fourth subframe ZO that is a subframe for observing ambient light. The drive circuit 81 of the control device 80 outputs blinking signals SS1, SS2, and SS3 to control the operations of the light sources 10R, 10G, and 10B, respectively, outputs drive signals SM1, SM2, and SM3 to control the operation of the transmissive liquid crystal panel 22, respectively, and outputs an on-off signal SW to control the operation of the switching half-wave plate 55.

[0056] In this case, when the first virtual image display device 100A is in the first subframe ZR of the image observation period, the first light source 10R emits a backlight BLR of a first color, and the transmissive liquid crystal panel 22 is in a display state of the first color component, the first virtual image display device 100A displays a first image light ML(R) representing the intensity distribution of the wavelength component of the first color among the image light ML. Similarly, when the first virtual image display device 100A is in the second subframe ZG of the image observation period, the second light source 10G emits a backlight BLG of a second color, and the transmissive liquid crystal panel 22 is in a display state of the second color component, the first virtual image display device 100A displays a second image light ML(G) representing the intensity distribution of the wavelength component of the second color among the image light ML. Furthermore, when the first virtual image display device 100A is in the third subframe ZB of the image observation period, the third light source 10B emits a backlight BLB of the third color, and the transmissive liquid crystal panel 22 is in the display state of the first color component, the first virtual image display device 100A displays the third image light ML(B) representing the intensity distribution of the wavelength component of the third color among the image light ML. In this way, the first virtual image display device 100A displays the full-color image light ML by repeating, in a sufficiently short cycle, the respective states of the subframes ZR, ZG, and ZB in which the image light ML(R), ML(G), and ML(B) representing the intensity distribution of the wavelength components of the three colors included in the image light ML are displayed one by one in a time-division manner.

[0057] In the first subframe ZR, the second light source 10G and the third light source 10B are in a transmissive state and do not emit backlights BLG and BLB, but transmit the first color backlight BLR emitted by the first light source 10R, and the transmissive liquid crystal panel 22 forms only the first image light ML(R) of the image light ML and does not form the second image light ML(G) or the third image light ML(B), so that only the first image light ML(R) representing the intensity distribution of the wavelength component of the first color is displayed out of the image light ML. Similarly, in the second sub-frame ZG, the first light source 10R is in a transmissive state not emitting backlight BLR, the third light source 10B is in a transmissive state not emitting backlight BLB and transmits the second-color backlight BLG emitted by the second light source 10G, and the transmissive liquid crystal panel 22 generates only the second image light ML(G) of the image light ML and does not generate the first image light ML(R) and the image light ML(B). Therefore, only the second image light ML(G) representing the intensity distribution of the wavelength component of the second color is displayed. Also, in the third sub-frame ZB, the first light source 10R and the second light source 10G are in a transmissive state not emitting backlights BLR and BLG, and the transmissive liquid crystal panel 22 generates only the third image light ML(B) of the image light ML and does not generate the first image light ML(R) and the second image light ML(G). Therefore, only the third image light ML(B) representing the intensity distribution of the wavelength component of the third color is displayed.

[0058] When the first virtual image display device 100A is in the fourth subframe ZO as an ambient light observation period, the light sources 10R, 10G, and 10B are in a transmissive state not emitting backlights BLR, BLG, and BLB, the transmissive liquid crystal panel 22 is in a non-display state, and the switching half-wave plate 55 is in an off state that transmits light as is, the ambient light OL passes through the light sources 10R, 10G, and 10B, the transmissive liquid crystal panel 22, and the switching half-wave plate 55 and reaches the eye EY of the wearer US. In this way, the first virtual image display device 100A enables a see-through display in which the full-color image light ML and the ambient light OL are superimposed in a time-division manner by repeating, in a sufficiently short cycle, a state in which the first color component, the second color component, and the third color component of the image light ML are displayed in a time-division manner during the image observation period including the subframes ZR, ZG, and ZB, and a state in which the ambient light OL is transmitted during the ambient observation period as the subframe ZO.

[0059] The virtual image display devices 100A, 100B or the optical unit 100 according to the first embodiment described above include a light source member 10 as a transmissive OLED panel that transmits external light OL in a first state and emits backlight BL in a second state, a transmissive display element 20 that is arranged opposite the transmissive OLED panel and further transmits the external light OL that has transmitted through the transmissive OLED panel in the first state and transmits the backlight BL emitted by the transmissive OLED panel in the second state to emit image light, and a transmissive display element 20 that is arranged opposite the transmissive OLED panel with the display element 20 interposed therebetween. the display element 20 and the imaging optical system 50, which are disposed on the transmissive OLED panel, and transmit at least a portion of external light OL in a first state and form an image light in a second state; and a control device 80 that controls the transmissive OLED panel, the display element 20 and the imaging optical system 50 to switch between the first state and the second state, wherein the transmissive OLED panel includes a third light source 10B as a first transmissive OLED element that emits a first backlight of a first color, and a second light source 10G as a second transmissive OLED element that is stacked on the third light source 10B as the first transmissive OLED element and emits a second backlight of a second color.

[0060] The virtual image display devices 100A, 100B, or the optical unit 100 described above use a transmissive OLED panel, which is a surface-emitting light source, as the light source member 10 that generates the backlight BL. As a result, the virtual image display devices 100A, 100B, or the optical unit 100 can uniformly light the backlight BL and suppress uneven brightness of the image. Furthermore, by using a transmissive OLED element, power consumption for generating the backlight BL can be reduced, the light source member 10 can be made smaller, and high transmittance for external light OL and good display of the image light ML can be achieved. Furthermore, the virtual image display devices 100A, 100B, or the optical unit 100 combine a first polarizing diffractive lens 51 that has positive power for image light having a first circular polarization with a second polarizing diffractive lens 52 that has positive power for image light having a second circular polarization after passing through the first polarizing diffractive lens 51, thereby realizing an imaging optical system 50 that is relatively thin and has a relatively short focal length.

[0061] Second Embodiment The virtual image display devices 100A, 100B, etc. of the second embodiment will be described below. The virtual image display devices 100A, 100B of the second embodiment are partially modified versions of the virtual image display devices 100A, 100B of the first embodiment, and descriptions of parts common to the virtual image display devices 100A, 100B of the first embodiment will be omitted.

[0062] 10, the transmissive liquid crystal panel 22 of the display element 20 according to this embodiment includes a first transmissive liquid crystal panel 22R, a second transmissive liquid crystal panel 22G, and a third transmissive liquid crystal panel 22B. The third transmissive liquid crystal panel 22B, the second transmissive liquid crystal panel 22G, and the first transmissive liquid crystal panel 22R are arranged in this order so as to face each other in parallel in the −Z direction from the outside world toward the eye EY of the wearer US.

[0063] 11 is a side cross-sectional view showing the optical unit 100 of the display optical systems 103a and 103b. As shown in FIG. 11, the first light source 10R and the first transmissive liquid crystal panel 22R operate as a first image light emitting device that emits a first image light ML(R) that represents the intensity distribution of a wavelength component of a first color in the image light ML. Similarly, the second light source 10G and the second transmissive liquid crystal panel 22G operate as a second image light emitting device that emits a second image light ML(G) that represents the intensity distribution of a wavelength component of a second color in the image light ML. Furthermore, the third light source 10B and the third transmissive liquid crystal panel 22B operate as a third image light emitting device that emits a third image light ML(B) that represents the intensity distribution of a wavelength component of a third color in the image light ML.

[0064] Referring to Figure 12, we will explain how the chromatic aberration of the polarizing diffractive lenses 51 and 52 is corrected by appropriately setting the distance from each of the transmissive liquid crystal panels 22R, 22G, and 22B to the first polarizing diffractive lens 51 and appropriately setting the dimensions of the pixels included in the display areas 12R, 12G, and 12B of each of the transmissive liquid crystal panels 22R, 22G, and 22B.

[0065] One of the causes of chromatic aberration in the polarized diffractive lenses 51, 52 is that the focal lengths of the polarized diffractive lenses 51, 52 vary depending on the wavelength of the incident light. More specifically, in the polarized diffractive lenses 51, 52, the focal lengths corresponding to light with shorter wavelengths are longer, and the focal lengths corresponding to light with longer wavelengths are shorter. Thus, the wavelength dependence of the focal lengths of the polarized diffractive lenses 51, 52 is opposite to the wavelength dependence of the focal lengths of refractive lenses. Therefore, in this embodiment, to correct the chromatic aberration in the polarized diffractive lenses 51, 52, the distance DB between the polarized diffractive lens 51 and the third-color transmissive liquid crystal panel 22B that emits light with shorter wavelengths, for example, the third image light ML(B) that represents the intensity distribution of the blue wavelength component of the image light ML, is set longer, and the distance DR between the polarized diffractive lens 51 and the first-color transmissive liquid crystal panel 22R that emits light with longer wavelengths, for example, the first image light ML(R) that represents the intensity distribution of the red wavelength component of the image light ML, is set shorter. In addition, the distance DG between the second color transmissive liquid crystal panel 22G, which emits light having an intermediate wavelength, for example, the second image light ML(G) representing the intensity distribution of the green wavelength component of the image light ML, and the polarized diffraction lens 51 is set to an intermediate length.

[0066] Here, if the pixel dimensions are the same in each of the transmissive liquid crystal panels 22R, 22G, and 22B, the pixels included in the display region 12B of the third-color transmissive liquid crystal panel 22B, which is at a longer distance DB from the polarized diffractive lenses 51 and 52, will appear relatively small when viewed from the eye EY of the wearer US, and the pixels included in the display region 12R of the first-color transmissive liquid crystal panel 22R, which is at a shorter distance DR from the polarized diffractive lenses 51 and 52, will appear relatively large. To correct this difference, in this embodiment, the dimensions of the pixels 14R, 14G, and 14B included in the display regions 12R, 12G, and 12B of the transmissive liquid crystal panels 22R, 22G, and 22B, respectively, are set appropriately depending on the distance from each of the transmissive liquid crystal panels 22R, 22G, and 22B to the imaging optical system 50. More specifically, the dimension 13B of the display area 12B of the third-color transmissive liquid crystal panel 22B, which has a longer distance DB from the polarizing diffractive lenses 51, 52, is set to be relatively large, while the dimension 13R of the display area 12R of the first-color transmissive liquid crystal panel 22R, which has a shorter distance DR from the polarizing diffractive lenses 51, 52, is set to be relatively small. Furthermore, the dimension 13G of the display area 12G of the second-color transmissive liquid crystal panel 22G, which has an intermediate distance DG from the polarizing diffractive lenses 51, 52, is set to be intermediate. As a result, the differences between the first dimension of the first pixel 14R included in the first transmissive liquid crystal panel 22R, the second dimension of the second pixel 14G included in the second transmissive liquid crystal panel 22G, and the third dimension of the third pixel 14B included in the third transmissive liquid crystal panel 22B cancel out the differences in the distances to the first polarizing diffractive lenses of the first pixel 14R, the second pixel 14G, and the third pixel 14B. Furthermore, the first pixel 14R, the second pixel 14G, and the third pixel 14B, which correspond to each other, have shapes that appear to overlap each other at a desired observation position.

[0067] 12, when the first-color transmissive liquid crystal panel 22R is moved 2.3 mm closer to the polarized diffractive lens 51 (when D2=2.3 mm in region DR1), the size of the pixels included in the display region 12R of the first-color transmissive liquid crystal panel 22R is reduced to 94% (13R / 13G=94% is set in region DR2) based on the position and size of the second-color transmissive liquid crystal panel 22G. Also, when the third-color transmissive liquid crystal panel 22B is moved 1.6 mm away from the polarized diffractive lens 51 (when D1=1.6 mm in region DR1), the size of the pixels included in the third-color transmissive liquid crystal panel 22B is expanded to 111% (13B / 13G=111% in region DR2). At this time, when viewed from the eye EY of the wearer US, the pixels included in each of the transmissive liquid crystal panels 22R, 22G, 22B appear to be overlapping and of the same size, thereby improving the image quality of the image light ML.

[0068] To maintain a stable positional relationship between the transmissive liquid crystal panels 22R, 22G, and 22B, transparent plate-like spacers 24A and 24B may be provided between the transmissive liquid crystal panels 22R, 22G, and 22B, and the transmissive liquid crystal panels 22R, 22G, and 22B and the spacers 24A and 24B may be fixed by adhesive or the like, as shown in Fig. 13. The spacers 24A and 24B may be made of glass or resin. In addition to the transmissive liquid crystal panels 22R, 22G, and 22B and the spacers 24A and 24B, some or all of the light sources 10R, 10G, and 10B, the polarizing plates 21A and 21B, the quarter-wave plate 23, and the imaging optical system 50 may also be fixed and integrated.

[0069] The display operation by the display optical systems 103a and 103b according to this embodiment will be described. The display operation by the display optical systems 103a and 103b according to this embodiment can be obtained by modifying the display operation according to the first embodiment described with reference to FIG. 9 as follows. That is, in this embodiment, the first-color transmissive liquid crystal panel 22R is driven by the first drive signal SM1 to form the first image light ML(R), the second-color transmissive liquid crystal panel 22G is driven by the second drive signal SM2 to form the second image light ML(G), and the third-color transmissive liquid crystal panel 22B is driven by the third drive signal SM3 to form the third image light ML(B). Other elements of the display operation by the display optical systems 103a and 103b according to this embodiment are the same as those in the first embodiment.

[0070] In this embodiment, in the first sub-frame ZR, the second light source 10G and the third light source 10B are in a transmissive state where they do not emit backlights BLR, BLG, and BLB, and the second-color transmissive liquid crystal panel 22G and the third-color transmissive liquid crystal panel 22B are in a non-display state where they do not form image lights ML(G) and ML(B), and transmit the first-color backlight BLR emitted by the first light source 10R. As a result, in the first sub-frame ZR, of the image light ML, only the first image light ML(R) representing the intensity distribution of the wavelength component of the first color is displayed, and the second image light ML(G) representing the intensity distribution of the wavelength component of the second color and the third image light ML(B) representing the intensity distribution of the wavelength component of the third color are not displayed. Similarly, in the second sub-frame ZG, the first light source 10R is in a transmissive state not emitting a backlight BLR and transmits the second-color backlight BLG emitted by the second light source 10G, the third light source 10B is in a transmissive state not emitting a backlight BLG, the first-color transmissive liquid crystal panel 22R is in a non-display state not forming image light ML(R) and transmits the image light ML(G) formed by the second-color transmissive liquid crystal panel 22G, and the third-color transmissive liquid crystal panel 22B is in a non-display state not forming image light ML(B). As a result, in the second sub-frame ZG, of the image light ML, only the second image light ML(G) representing the intensity distribution of the wavelength component of the second color is displayed, and the first image light ML(R) representing the intensity distribution of the wavelength component of the first color and the third image light ML(B) representing the intensity distribution of the wavelength component of the third color are not displayed. Furthermore, in the third sub-frame ZB, the first light source 10R and the second light source 10G are in a transmissive state where they do not emit backlights BLR, BLG, and transmit the third-color backlight BLB emitted by the third light source 10B, and the first-color transmissive liquid crystal panel 22R and the second-color transmissive liquid crystal panel 22G are in a non-display state where they do not form image light ML(R), ML(G), and transmit the image light ML(B) formed by the third-color transmissive liquid crystal panel 22B. As a result, in the third sub-frame ZB, of the image light ML, only the third image light ML(B) representing the intensity distribution of the wavelength component of the third color is displayed, and the first image light ML(R) representing the intensity distribution of the wavelength component of the first color and the second image light ML(G) representing the intensity distribution of the wavelength component of the second color are not displayed.

[0071] Furthermore, when the first virtual image display device 100A is in the fourth subframe ZO as the ambient light observation period, the light sources 10R, 10G, and 10B are in a transmissive state not emitting backlights BLR, BLG, and BLB, the transmissive liquid crystal panels 22R, 22G, and 22B are in a non-display state, and the switching half-wave plate 55 is in an off state allowing light to pass directly, the ambient light OL passes through the light sources 10R, 10G, and 10B, the transmissive liquid crystal panels 22R, 22G, and 22B, and the switching half-wave plate 55 and reaches the eye EY of the wearer US. In this way, the first virtual image display device 100A enables a see-through display in which the full-color image light ML and the ambient light OL are superimposed in a time-division manner by repeating, in a sufficiently short cycle, a state in which the image light ML is displayed during the image observation period including the subframes ZR, ZG, and ZB and a state in which the ambient light OL is transmitted during the ambient light observation period as the subframe ZO.

[0072] A modified example of this embodiment will be described with reference to Fig. 14. Fig. 14 is a diagram illustrating display optical systems 103a and 103b of this modified example, and corresponds to Fig. 11. The configuration of Fig. 14 is the same as that of Fig. 11, except that the first polarizing diffractive lens 151 and the second polarizing diffractive lens 152 serving as the polarizing diffractive lens GP1 shown in Fig. 8 are replaced with the polarizing diffractive lens GP2 shown in Fig. 8. In this case, left-handed circularly polarized LCP image light ML is emitted from the display 40 in the early stage of time division, and left-handed circularly polarized LCP external light OL is transmitted by the display 40 in the later stage of time division.

[0073] In the imaging optical system 50, the first polarized diffractive lens 151 and the second polarized diffractive lens 152 are polarized diffractive lenses GP2 shown in the third region CR3 and the fourth region CR4 of Figure 8, and when the image light ML and external light OL incident from the display 40 are left-handed circularly polarized light LCP, they function as optical elements with positive power with respect to the image light ML and external light OL, reducing the divergence of the image light ML and external light OL while reversing the direction of polarization rotation to convert them to right-handed circularly polarized light RCP.

[0074] During the image observation period, the image light ML that has passed through first polarizing diffractive lens 151 is incident on switching half-wave plate 55, converted back into left-handed circularly polarized light LCP, and then incident on second polarizing diffractive lens 152. As a result, first polarizing diffractive lens 151 and second polarizing diffractive lens 152 relatively converge the image light ML passing through from the display device 40 side, and change the first circularly polarized light, left-handed circularly polarized light LCP, into the second circularly polarized light, right-handed circularly polarized light RCP. In this case, since imaging optical system 50 has positive power, it becomes possible to observe the image light ML.

[0075] On the other hand, during the external light observation period, external light OL that has passed through first polarizing diffractive lens 151 is incident on switching half-wave plate 55, maintained as right-handed circularly polarized light RCP, and then incident on second polarizing diffractive lens 152. As a result, first polarizing diffractive lens 151 and second polarizing diffractive lens 152 cause external light OL passing through from the display 40 side to travel in a substantially straight line, and maintain it as left-handed circularly polarized light LCP, which is the first circularly polarized light. In this case, since imaging optical system 50 has no power, it becomes possible to observe external light OL.

[0076] The modified example shown in FIG. 14 is also applicable to the first embodiment.

[0077] In the virtual image display devices 100A, 100B or the optical unit 100 according to the present embodiment described above, even when the first color component, the second color component, and the third color component of the image light ML are formed by three transmissive liquid crystal panels 22R, 22G, and 22B, respectively, the chromatic aberration of the polarized diffractive lenses 51 and 52 included in the imaging optical system 50 can be corrected by arranging each of the transmissive liquid crystal panels 22R, 22G, and 22B at different appropriate distances from the imaging optical system 50.

[0078] Third Embodiment In the first and second embodiments described above, the configurations of the virtual image display devices 100A, 100B and the optical unit 100 using the transmissive liquid crystal panel 22 without a color filter are described. In this embodiment, the configurations of the virtual image display devices 100A, 100B and the optical unit 100 using the transmissive liquid crystal panel 22 with a color filter are described.

[0079] When the transmissive liquid crystal panel 22 is equipped with a color filter, it can simultaneously emit a first image light ML(R) of a first color, a second image light ML(G) of a second color, and a third image light ML(B) of a third color out of the image light ML. Furthermore, in this case, the first light source 10R, the second light source 10G, and the third light source 10B of the light source member 10 can simultaneously emit a backlight BLR of the first color, a backlight BLG of the second color, and a backlight BLB of the third color, respectively. As a result, in the virtual image display devices 100A, 100B and the optical unit 100 according to this embodiment, the ratio of the image light ML and the external light OL to be superimposed in a time-division manner can be selected from a wider range.

[0080] The configurations of the virtual image display devices 100A, 100B and the optical unit 100 according to this embodiment are partially modified from the configurations of the first embodiment. Of the configurations of the virtual image display devices 100A, 100B and the optical unit 100 according to this embodiment, descriptions of parts common to the configurations of the first embodiment may be omitted.

[0081] 15, the display element 20 according to the present embodiment includes a first color filter 41r, a second color filter 41g, and a third color filter 41b in addition to the components included in the display element 20 according to the first embodiment shown in FIG. 4. Each of the pixels PX included in the display element 20 according to the present embodiment includes a first color sub-pixel PXs(R), a second color sub-pixel PXs(G), and a third color sub-pixel PXs(B). Here, the first color sub-pixel PXs(R) includes the first color filter 41r, the second color sub-pixel PXs(G) includes the second color filter 41g, and the third color sub-pixel PXs(B) includes the third color filter 41b.

[0082] The state of light passing through the display 40 according to this embodiment will be described with reference to Fig. 16. In Fig. 16, a first region ER1 indicates a case where the first display optical system 103a is in an image observation period and the display 40 is in a display state, and a second region ER2 indicates a case where the first display optical system 103a is in an ambient light observation period and the display 40 is in a non-display state.

[0083] 16, when the display device 40 is in a display state during the video observation period, the light source member 10 emits backlight BL toward the display element 20. More specifically, of the light source member 10, the light-emitting layers 104R, 104G, and 104B shown in FIG. 3 simultaneously emit backlight BLR, BLG, and BLB toward the display element 20.

[0084] The first-color backlight BLR passes through the first-color color filter 41r to reach the first-color sub-pixel PXs(R), but is blocked by the second-color and third-color color filters 41g and 41b and does not reach the second-color and third-color sub-pixels PXs(G) and PXx(B). Similarly, the second-color backlight BLG passes through the first-color color filter 41g to reach the first-color sub-pixel PXs(G), but is blocked by the first-color and third-color color filters 41r and 41b and does not reach the first-color and third-color sub-pixels PXs(R) and PXx(B). Furthermore, the third-color backlight BLB passes through the third-color color filter 41b to reach the third-color sub-pixel PXs(B), but is blocked by the first-color and second-color color filters 41r and 41g and does not reach the first-color and second-color sub-pixels PXs(R) and PXx(G).

[0085] The first-color sub-pixels PXs(R) form a first image of a first color component of the image. When the first-color sub-pixels are forming the first image, the first-color light-emitting layer 104R and the first-color sub-pixels PXs(R) emit a first image light ML(R) of the first color component of the image light ML. Similarly, the second-color sub-pixels PXs(G) form a second image of a second color component of the image. When the second-color backlight BLG is transmitted through the second-color sub-pixels are forming the second image, the second-color light-emitting layer 104G and the second-color sub-pixels PXs(G) emit a second image light ML(G) of the second color component of the image light ML. Furthermore, the third-color sub-pixels PXs(B) form a third image of a third color component of the image. When the third color backlight BLB passes through the third color sub-pixels that are forming the third image, the third color light emitting layer 104B and the third color sub-pixels PXs(B) emit the second image light ML(B) of the third color component from the image light ML.

[0086] As shown in the second region ER2 of FIG. 16 , when the display 40 is in a non-display state during the external light observation period, the light source member 10 is in a non-emitting state, i.e., an extinguished state. At this time, the light source member 10 and the sub-pixels PXs(R), PXs(G), and PXs(B) of the display element 20 are each in a maximum transmission state. At this timing, external light OL passes through the light source member 10 and enters the display element 20. Of the external light OL entering the display element 20, first external light OL(R) that has passed through the first-color color filter 41r, second external light OL(G) that has passed through the second-color color filter 41g, and third external light OL(B) that has passed through the third-color color filter 41b further pass through the sub-pixels PXs(R), PXs(G), and PXs(B) and the quarter-wave plate 23 to reach the eye EY of the wearer US.

[0087] The polarizing plates 21A, 21B and the quarter-wave plate 23, and the changes in polarization of the backlights BLR, BLG, BLB, the image light ML(R), ML(G), ML(B), and the external light OL, OL(R), OL(G), OL(B) are the same as those in the first embodiment described with reference to Figure 5.

[0088] The display operation of the display optical systems 103a and 103b according to this embodiment will be described with reference to Fig. 17. In the timing chart of Fig. 17, the horizontal axis represents time, and from top to bottom, the diagram shows examples of waveforms of the blinking signal SS of each light source 10R, 10G, and 10B of the light source member 10, the first drive signal SM1 for displaying the first color component, the second drive signal SM2 for displaying the second color component, and the third drive signal SM3 for displaying the third color component of the transmissive liquid crystal panel 22, and the on / off signal SW of the switching half-wave plate 55.

[0089] When the first virtual image display device 100A is in the first sub-frame Z1 for image observation, the first light source 10R, the second light source 10G, and the third light source 10B of the light source member 10 emit a backlight BLR of a first color, a backlight BLG of a second color, and a backlight BLB of a third color, respectively. Also, when the first virtual image display device 100A is in the first sub-frame Z1 for image observation, the first color sub-pixels PXs(R), the second color sub-pixels PXs(G), and the third color sub-pixels PXs(B) of the transmissive liquid crystal panel 22 display first image light ML(R) representing the intensity distribution of the wavelength component of the first color, second image light ML(G) representing the intensity distribution of the wavelength component of the second color, and third image light ML(B) representing the intensity distribution of the wavelength component of the third color, respectively, of the image light ML. As a result, when the first virtual image display device 100A is in the first sub-frame Z1 for image observation, it simultaneously displays the first image light ML(R), the second image light ML(G), and the third image light ML(B) that constitute the image light ML.

[0090] When the first virtual image display device 100A is in the second subframe Z2 as the ambient light observation period, the first light source 10R, the second light source 10G, and the third light source 10B of the light source member 10 are in a transmissive state in which they do not emit backlights BLR, BLG, and BLB, respectively, the subpixels PXs(R), PSx(G), and PXs(B) of the transmissive liquid crystal panel 22 are in a non-display state, and the switching half-wave plate 55 is in an off state in which it transmits light as is. Therefore, when the first virtual image display device 100A is in the second subframe Z2 as the ambient light observation period, the ambient light OL reaches the eye EY of the wearer US as ambient light OL(R), OL(G), and OL(B) that has passed through the color filters 41r, 41g, and 41b.

[0091] The first virtual image display device 100A of this embodiment enables a see-through display in which full-color image light ML and external light OL are superimposed in a time-division manner by repeating the first sub-frame Z1 and the second sub-frame Z2 at a sufficiently short period.

[0092] In addition to the effects of the virtual image display devices 100A, 100B and optical unit 100 according to the first embodiment, the virtual image display devices 100A, 100B and optical unit 100 according to the present embodiment can select from a wider range the ratio of the image light ML and the external light OL that are superimposed in a time-division manner.

[0093] [Modification] In the third embodiment described above, the first light source 10R, the second light source 10G, and the third light source 10B of the light source member 10 are stacked separately, as shown in FIG. 3. As a modification of this configuration, as shown in FIG. 18, a fourth light source 10RG may be provided, which integrates the first light source 10R and the second light source 10G of FIG. 3. The cross-sectional view of FIG. 18 is the cross-sectional view of FIG. 3 with the following modifications: the first light source 10R and the first adhesive layer 1081 are removed, and the second light source 10G is replaced with the fourth light source 10RG. The fourth light source 10RG includes a fourth transparent substrate 101RG, a fourth transparent anode 102RG, a fourth hole transport layer 103RG, a first light-emitting layer 104R, a second light-emitting layer 104G, a fourth electron transport layer 105RG, a fourth transparent cathode 106RG, and a first sealing layer 107RG, which are stacked in this order in the −Z direction of a Cartesian coordinate system.

[0094] In the fourth light source 10RG, when an appropriate voltage is applied between the fourth transparent anode 102RG and the fourth transparent cathode 106RG, the first light-emitting layer 104R emits a first color backlight BLR, and the second light-emitting layer 104G emits a second color backlight BLG.

[0095] Other configurations and operations of the light source member 10 are the same as those of the third embodiment shown in Fig. 3. Other configurations and operations of the virtual image display devices 100A and 100B and the optical unit 100 according to this modified example are also the same as those of the third embodiment.

[0096] According to this modification, in addition to the effects of the third embodiment, the light source member 10 can be further reduced in size.

[0097] In the above description, it is assumed that the HMD 200 is used by being worn on the head, but the virtual image display devices 100A and 100B can also be used as handheld displays that are not worn on the head but are peered into like binoculars. In other words, in the present invention, the head-mounted display also includes a handheld display.

[0098] In a specific embodiment, the virtual image display device includes a transmissive OLED (Organic Light Emitting Diode) panel that transmits external light in a first state and emits backlight in a second state; a transmissive display element facing the transmissive OLED panel and that further transmits the external light that has passed through the transmissive OLED panel in the first state and transmits the backlight emitted by the transmissive OLED panel in the second state to emit image light; and an imaging optical system facing the transmissive OLED panel across the display element and that transmits at least a portion of the external light in the first state and forms an image from the image light in the second state. The transmissive OLED panel includes a first transmissive OLED element that emits light of a first color, and a second transmissive OLED element that is stacked on the first transmissive OLED element and emits light of a second color.

[0099] In a specific embodiment, the virtual image device further includes a control device that controls the transmissive OLED panel, the display element, and the imaging optical system to switch between the first state and the second state.

[0100] In the virtual image display device, a transmissive OLED panel is used as a light source member that emits backlight, thereby realizing uniformity of the backlight and reduction in power consumption and size of the light source member.

[0101] In a specific embodiment of the virtual image display device, the transmissive OLED panel further includes a third transmissive OLED element stacked on the second transmissive OLED element and emitting light of a third color, the transmissive OLED panel emits light of the first color in the second state, emits light of the second color in the third state, and emits light of the third color in the fourth state, the display element transmits the light emitted by the transmissive OLED panel in the third and fourth states to display an image of the image light, the imaging optical system forms an image in the third and fourth states, and the control device controls the transmissive OLED panel, the display element, and the optical system to further switch between the third and fourth states.

[0102] In the virtual image display device, the light source member emits three-color backlight in a time-division manner, and the display element displays image light that represents the intensity distribution of the three-color wavelength components of the image light in a time-division manner.

[0103] In a specific embodiment of the virtual image display device, the display element includes a transmissive liquid crystal panel that switches between displaying a first image representing the intensity distribution of wavelength components of a first color, a second image representing the intensity distribution of wavelength components of a second color, and a third image representing the intensity distribution of wavelength components of a third color in a time-division manner, and the transmissive liquid crystal panel displays the first image of the images in the second state, the second image of the images in the third state, and the third image of the images in the fourth state.

[0104] In the virtual image display device, a single transmissive liquid crystal panel can be used as the display element.

[0105] In a specific embodiment of the virtual image display device, the display element includes a first transmissive liquid crystal panel that, in the second state, displays a first image representing the intensity distribution of wavelength components of a first color among the images; a second transmissive liquid crystal panel that faces the first transmissive liquid crystal panel and, in the third state, displays a second image representing the intensity distribution of wavelength components of a second color among the images; and a third transmissive liquid crystal panel that faces the second transmissive liquid crystal panel and, in the fourth state, displays a third image representing the intensity distribution of wavelength components of a third color among the images.

[0106] The virtual image display device can employ three transmissive liquid crystal panels as display elements.

[0107] In a specific aspect of the virtual image display device, the transmissive OLED panel further includes a third transmissive OLED element stacked on the second transmissive OLED element and emitting light of a third color, and in the second state, the first transmissive OLED element, the second transmissive OLED element, and the third transmissive OLED element emit light simultaneously. The display element includes a transmissive liquid crystal panel including a plurality of pixels arranged in a matrix, and each of the plurality of pixels includes: a first color filter that selectively transmits light of the first color; a first sub-pixel facing the first color filter that displays a first image representing the intensity distribution of wavelength components of the first color in an image of the image light; a second color filter that selectively transmits light of the second color; a second sub-pixel facing the second color filter that displays a second image representing the intensity distribution of wavelength components of the second color in the image; a third color filter that selectively transmits light of the third color; and a third sub-pixel facing the third color filter that displays a third image representing the intensity distribution of wavelength components of the third color in the image.

[0108] In the virtual image display device, a single transmissive liquid crystal panel equipped with three color filters can be used as a display element.

[0109] In a specific aspect of the virtual image display device, in the second state, the first transmissive OLED element emits light of a first color, and the second transmissive OLED element emits light of a second color and light of a third color, the display element comprises a transmissive liquid crystal panel including a plurality of pixels arranged in a matrix, each of the plurality of pixels including a first color filter that selectively transmits light of the first color, and a first sub-pixel facing the first color filter that displays a first image representing an intensity distribution of wavelength components of the first color from an image of the image light; The display device includes a second color filter that selectively transmits light of a second color, a second sub-pixel that faces the second color filter and displays a second image that represents the intensity distribution of wavelength components of the second color among the images, a third color filter that selectively transmits light of a third color, and a third sub-pixel that faces the third color filter and displays a third image that represents the intensity distribution of wavelength components of the third color among the images, and in the second state, the first sub-pixel, the second sub-pixel, and the third sub-pixel display the first image, the second image, and the third image, respectively.

[0110] The virtual image display device can employ a configuration including, as the light source member, a first transmissive OLED element that emits backlight of one color and a second transmissive OLED element that emits backlight of two colors.

[0111] In a specific aspect of the virtual image display device, the imaging optical system includes: a first polarizing diffractive lens facing the transmissive liquid crystal panel and having positive power for the first image light of the first image having circular polarization and the second image light of the second image having circular polarization; a second polarizing diffractive lens facing the transmissive liquid crystal panel across the first polarizing diffractive lens and having positive power for the first image light and the second image light that are incident through the first polarizing diffractive lens; and a switching half-wave plate disposed between the first polarizing diffractive lens and the second polarizing diffractive lens and functions as a half-wave plate in a first state to cancel out the powers of the first polarizing diffractive lens and the second polarizing diffractive lens, and turning off its function in a second state to cause both the first polarizing diffractive lens and the second polarizing diffractive lens to function as positive lenses; and the control device further controls the switching half-wave plate to switch between the first state and the second state.

[0112] In the virtual image display device, both of the two polarizing diffractive lenses are configured to have positive power with respect to the image light, and a relatively thin imaging optical system with a relatively short focal length can be realized.

[0113] In a specific aspect, the virtual image display device includes a first polarizing diffractive lens that faces the first transmissive liquid crystal panel and the second transmissive liquid crystal panel and has positive power with respect to a first image light of a first image and a second image light of a second image, both of which have circular polarization; a second polarizing diffractive lens that faces the first transmissive liquid crystal panel and the second transmissive liquid crystal panel across the first polarizing diffractive lens and has positive power with respect to the first image light and the second image light, both of which have circular polarization and which are incident via the first polarizing diffractive lens; and a polarizing diffractive lens that is disposed between the first polarizing diffractive lens and the second polarizing diffractive lens and functions as a half-wave plate in the first state. and a switching half-wave plate that cancels out the powers of the first polarizing diffractive lens and the second polarizing diffractive lens by switching off the function in a second state, causing both the first polarizing diffractive lens and the second polarizing diffractive lens to function as positive lenses, wherein the control device further controls the switching half-wave plate to switch between the first state and the second state, a first wavelength of the first color is shorter than a second wavelength of the second color, and a first dimension of each of a plurality of first pixels included in the first transmissive liquid crystal panel is larger than a second dimension of each of a plurality of second pixels included in the second transmissive liquid crystal panel.

[0114] In the virtual image display device, the two polarized diffractive lenses are both configured to have positive power with respect to the image light, enabling a relatively thin imaging optical system with a relatively short focal length to be realized. Furthermore, by using an image light output device that is located at a different distance from the polarized diffractive lens for each color component of the image light, the chromatic aberration of the polarized diffractive lens can be corrected.

[0115] In a specific aspect, the optical unit includes: a transmissive OLED panel that transmits external light in a first state and emits backlight in a second state; a transmissive display element that faces the transmissive OLED panel and further transmits the external light that has passed through the transmissive OLED panel in the first state and transmits the backlight emitted by the transmissive OLED panel in the second state to emit image light; and an imaging optical system that faces the transmissive OLED panel across the display element and transmits at least a portion of the external light in the first state and forms an image from the image light in the second state. The transmissive OLED panel includes a first transmissive OLED element that emits light of a first color, and a second transmissive OLED element that is stacked on the first transmissive OLED element and emits light of a second color.

[0116] In the optical unit, a transmissive OLED panel is used as the light source member that emits the backlight, thereby realizing uniformity of the backlight and reduction in the power consumption and size of the light source member. [Explanation of symbols]

[0117] 10...light source member, 10R, 10G, 10B...light source, 12R, 12G, 12B...display area, 13R, 13G, 13B...dimensions, 14R, 14G, 14G...pixel, 20...display element, 21A, 21B...polarizing plate, 22, 22R, 22G, 22B...transmissive liquid crystal panel, 23...quarter wave plate, 24A, 24B...spacer, 40...display, 50...imaging optical system, 51, 151...first polarized diffractive lens, 52, 152...second polarized diffractive lens, 55...switching half wave plate, 55a...liquid crystal layer, 55b, 55c...substrate, 80...control device, 81...drive circuit, 90...user terminal, 100...optical unit, 100A, 100B...virtual image display device , 100C...Temple, 101...Support member, 102...Driver, 102a, 102b...Display driver, 103a, 103b...Display optical system, 106...Support device, 200...Head-mounted display device, AX...Optical axis, BL, BLR, BLG, BLG...Backlight, DR, DG...Distance, EY...Eye, FP, FP'...Focus, GP1, GP2...Polarized diffractive lens, L1, L2...Light beam, LCP...Left-handed circularly polarized light, RCP...Right-handed circularly polarized light, ML...Image light, OL...External light, PP...Pupil position, SS1, SS2, SS3...Blinking signal, SM1, SM2, SM3...Drive signal, SW...On / Off signal, US...Wearer, Z1, Z2, ZR, ZG, ZB, ZO...Subframe

Claims

1. a transmissive OLED (Organic Light Emitting Diode) panel that transmits external light in a first state and emits backlight in a second state; a transmissive display element facing the transmissive OLED panel, which in the first state further transmits the external light that has passed through the transmissive OLED panel, and which in the second state transmits the backlight emitted by the transmissive OLED panel to emit image light; an imaging optical system that faces the transmissive OLED panel with the display element interposed therebetween, transmits at least a part of the external light in the first state, and forms an image of the video light in the second state; The transmissive OLED panel comprises: a first transmissive OLED element that emits light of a first color; a second transmissive OLED element that is stacked on the first transmissive OLED element and emits light of a second color; Equipped with Virtual image display device.

2. a control device that controls the transmissive OLED panel, the display element, and the imaging optical system to switch between the first state and the second state; Further equipped The virtual image display device according to claim 1 .

3. The transmissive OLED panel comprises: a third transmissive OLED element that is stacked on the second transmissive OLED element and emits light of a third color; Furthermore, the transmissive OLED panel emits light of the first color in the second state, emits light of the second color in the third state, and emits light of the third color in the fourth state; the display element transmits light emitted by the transmissive OLED panel in the third state and the fourth state to display an image of the image light; the imaging optical system forms the image in the third state and the fourth state, the control device controls the transmissive OLED panel, the display element, and the imaging optical system to further switch between the third state and the fourth state; The virtual image display device according to claim 2 .

4. The display element is a transmissive liquid crystal panel that displays, in a time-division switching manner, a first image representing an intensity distribution of the wavelength component of the first color, a second image representing an intensity distribution of the wavelength component of the second color, and a third image representing an intensity distribution of the wavelength component of the third color, among the images; Equipped with The transmissive liquid crystal panel is In the second state, the first image is displayed among the images; In the third state, the second image is displayed among the images; In the fourth state, the third image is displayed among the images. The virtual image display device according to claim 3 .

5. The display element is a first transmissive liquid crystal panel that displays, in the second state, a first image representing an intensity distribution of a wavelength component of the first color among the images; a second transmissive liquid crystal panel facing the first transmissive liquid crystal panel, which displays a second image representing an intensity distribution of a wavelength component of the second color in the third state; a third transmissive liquid crystal panel facing the second transmissive liquid crystal panel, which displays a third image representing an intensity distribution of a wavelength component of the third color among the images in the fourth state; Equipped with The virtual image display device according to claim 3 .

6. The transmissive OLED panel comprises: a third transmissive OLED element that is stacked on the second transmissive OLED element and emits light of a third color; Furthermore, In the second state, the first transmissive OLED element, the second transmissive OLED element, and the third transmissive OLED element simultaneously emit light; The display element is A transmissive liquid crystal panel containing multiple pixels arranged in a matrix. Equipped with Each of the plurality of pixels is a first color filter that selectively transmits light of the first color; a first sub-pixel facing the first color filter and displaying a first image representing an intensity distribution of a wavelength component of the first color in the image of the image light; a second color filter that selectively transmits light of the second color; a second sub-pixel facing the second color filter and displaying a second image representing an intensity distribution of the wavelength component of the second color in the image; a third color filter that selectively transmits light of the third color; a third sub-pixel facing the third color filter and displaying a third image representing an intensity distribution of a wavelength component of the third color in the image; Equipped with The virtual image display device according to claim 2 .

7. In the second state, the first transmissive OLED element emits light of the first color, and the second transmissive OLED element emits light of the second color and light of a third color; The display element is A transmissive liquid crystal panel containing multiple pixels arranged in a matrix. Equipped with Each of the plurality of pixels is a first color filter that selectively transmits light of the first color; a first sub-pixel facing the first color filter and displaying a first image representing an intensity distribution of a wavelength component of the first color in the image of the image light; a second color filter that selectively transmits light of the second color; a second sub-pixel facing the second color filter and displaying a second image representing an intensity distribution of the wavelength component of the second color in the image; a third color filter that selectively transmits light of the third color; a third sub-pixel facing the third color filter and displaying a third image representing an intensity distribution of a wavelength component of the third color in the image; Equipped with In the second state, the first sub-pixel, the second sub-pixel, and the third sub-pixel display the first image, the second image, and the third image, respectively. The virtual image display device according to claim 2 .

8. The imaging optical system includes: a first polarizing diffractive lens facing the transmissive liquid crystal panel and having positive power with respect to a first image light of the first image and a second image light of the second image, each having circular polarization; a second polarizing diffractive lens that faces the transmissive liquid crystal panel across the first polarizing diffractive lens and has positive power with respect to the first image light and the second image light that are incident through the first polarizing diffractive lens and have circular polarization; a switching half-wave plate that is disposed between the first polarizing diffractive lens and the second polarizing diffractive lens, and functions as a half-wave plate in the first state to cancel out the powers of the first polarizing diffractive lens and the second polarizing diffractive lens, and turns off its function in the second state to cause both the first polarizing diffractive lens and the second polarizing diffractive lens to function as positive lenses; Equipped with the control device further controls the switching half-wave plate to switch between the first state and the second state.

8. The virtual image display device according to claim 4, 6 or 7.

9. The imaging optical system includes: a first polarizing diffractive lens facing the first transmissive liquid crystal panel and the second transmissive liquid crystal panel, the first polarizing diffractive lens having positive power with respect to a first image light of the first image and a second image light of the second image, each having circular polarization; a second polarizing diffractive lens that faces the first transmissive liquid crystal panel and the second transmissive liquid crystal panel across the first polarizing diffractive lens and has positive power with respect to the first image light and the second image light that are incident through the first polarizing diffractive lens and have circular polarization; a switching half-wave plate that is disposed between the first polarizing diffractive lens and the second polarizing diffractive lens, and functions as a half-wave plate in the first state to cancel out the powers of the first polarizing diffractive lens and the second polarizing diffractive lens, and turns off its function in the second state to cause both the first polarizing diffractive lens and the second polarizing diffractive lens to function as positive lenses; Equipped with the control device further controls the switching half-wave plate to switch between the first state and the second state; a first wavelength of the first color is shorter than a second wavelength of the second color; a first dimension of each of the plurality of first pixels included in the first transmissive liquid crystal panel is larger than a second dimension of each of the plurality of second pixels included in the second transmissive liquid crystal panel; The virtual image display device according to claim 5 .

10. a transmissive OLED panel that transmits external light in a first state and emits backlight in a second state; a transmissive display element facing the transmissive OLED panel, which in the first state further transmits the external light that has passed through the transmissive OLED panel, and which in the second state transmits the backlight emitted by the transmissive OLED panel to emit image light; an imaging optical system that faces the transmissive OLED panel with the display element interposed therebetween, that transmits at least a portion of the external light in the first state, and that forms an image of the video light in the second state; Equipped with The transmissive OLED panel comprises: a first transmissive OLED element that emits light of a first color; a second transmissive OLED element that is stacked on the first transmissive OLED element and emits light of a second color; Equipped with Optical unit.

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