Virtual image display device and optical unit

Abstract

To correct chromatic aberration of a polarizing diffraction lens.SOLUTION: A virtual image display device comprises: a first image light emission device that emits first image light of a first color in a first state; a second image light emission device that emits second image light of a second color in a second state and transmits light in a state other than the second state; a first polarizing diffraction lens having positive power for the first image light and the second image light, which have circularly polarized light; a second polarizing diffraction lens having positive power for the first image light and the second image light, which are incident through the first polarizing diffraction lens and have the circularly polarized light; and a control device that controls the first image light emission device and the second image light emission device 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 a first pixel included in the first image light emission device is larger than a second dimension of a second pixel included in the second image light emission device.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 that uses a polarized diffractive lens. [Background technology]

[0002] A heat-formed multilayer reflective polarizer is known, which has at least one internal layer that is substantially rotationally symmetric with respect to an optical axis passing through the apex of the heat-formed multilayer reflective polarizer, is convex along first and second axes orthogonal to the optical axis, and is substantially optically uniaxial at at least one first location away from the apex, and has a radial distance r1 from the optical axis and a displacement s1 from a plane perpendicular to the optical axis at the apex, where s1 / r1 is at least 0.2 (Patent Document 1). This heat-formed multilayer reflective polarizer is heavy because it includes thick lenses. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2018-500584 Summary of the Invention [Problem to be solved by the invention]

[0004] It is expected that relatively thin and light polarized diffractive lenses will be used instead of relatively heavy thick lenses, but it is difficult to correct chromatic aberration in polarized diffractive lenses. [Means for solving the problem]

[0005] According to one aspect of the present invention, a virtual image display device includes a first image light output device that outputs first image light of a first color in a first state, a second image light output device that is disposed opposite the first image light output device, that outputs second image light of a second color in a second state, and that transmits the first image light in states other than the second state, a first polarized diffractive lens that is disposed opposite the first image light output device and the second image light output device, and that has positive power with respect to the first image light and the second image light having circular polarization, and ... second polarized diffractive lens that is disposed opposite the first image light output device and the second image light output device, with the first polarized diffractive lens sandwiched therebetween. and a second polarized diffractive lens arranged opposite the second image light-emitting device and having positive power for the first image light and the second image light which are incident through the first polarized diffractive lens and have circular polarization; and a control device which controls the first image light-emitting device and the second image light-emitting device to switch between a first state and a second state, wherein 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 image light-emitting device is larger than a second dimension of each of a plurality of second pixels included in the second image light-emitting device.

[0006] An optical unit according to one aspect of the present invention includes a first image light output device that outputs first image light of a first color in a first state; a second image light output device that is disposed opposite the first image light output device, that outputs second image light of a second color in a second state, and that transmits the first image light in states other than the second state; a first polarizing diffractive lens that is disposed opposite the first image light output device and the second image light output device, and that has positive power with respect to the first image light and the second image light having circular polarization; and a first image light output device that is disposed opposite the first image light output device and the second image light output device, with the first polarizing diffractive lens sandwiched therebetween. and a second polarized diffractive lens arranged opposite the second image light-emitting device and having positive power for the first image light and the second image light which are incident through the first polarized diffractive lens and have circular polarization; and a control device which controls the first image light-emitting device and the second image light-emitting device to switch between a first state and a second state, wherein 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 image light-emitting device is larger than a second dimension of each of a plurality of second pixels included in the second image light-emitting device. [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. 1 is a conceptual perspective view illustrating a structure of a virtual image display device. [Figure 3] FIG. 2 is a side cross-sectional view illustrating an imaging system of the virtual image display device. [Figure 4] 1A and 1B are a perspective view and a rear view illustrating the state of light rays in an imaging system. [Figure 5] FIG. 1 is a conceptual perspective view illustrating the function of a polarized diffractive lens. [Figure 6] 3A and 3B are a front view and a cross-sectional view illustrating the positional relationship and dimensions of a transmission type imager. [Figure 7] FIG. 10 is a cross-sectional view illustrating the positional relationship between a transmission imager and a spacer. [Figure 8] 10 is a chart illustrating the operation of the virtual image display device. [Figure 9] FIG. 10 is a side cross-sectional view illustrating a virtual image display device according to a modified example. [Figure 10] FIG. 10 is a side cross-sectional view illustrating a virtual image display device according to a second embodiment. [Figure 11] 10 is a chart illustrating the operation of the virtual image display device according to the second embodiment. 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] Fig. 2 is a 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 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, and a display member 20 that generates and emits image light ML. The light source member 10 emits light of the first, second, and third colors as backlight BL. 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 the drive device 102. The display member 20 of the display 40 is disposed close to the eye EY with an imaging system 50 sandwiched therebetween, enabling observation of a virtual image formed by the image light ML and see-through viewing of the outside world. In the first display optical system 103a, the distance between the eye EY and the imaging system 50 in the direction of the optical axis AX is, for example, approximately 10 mm to 20 mm. The distance between the transmissive liquid crystal panel 22 of the display 40 and the imaging system 50 in the direction of the optical axis AX is, for example, about 5 mm to 25 mm.

[0013] The display member 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 third transmissive liquid crystal panel 22B for a third color, a second transmissive liquid crystal panel 22G for a second color, a first transmissive liquid crystal panel 22R for a first color, a second polarizing plate 21B, and a quarter-wave plate 23. The display member 20 has a structure in which the polarizing plates 21A and 21B, the transmissive liquid crystal panels 22R, 22G, and 22B, and the quarter-wave plate 23 are stacked and integrated by a frame (not shown). The first polarizing plate 21A and the third transmissive liquid crystal panel 22B are disposed adjacent to each other with a predetermined distance or less between them. The first transmissive liquid crystal panel 22R and the second polarizing plate 21B are disposed adjacent to each other with a predetermined distance or less between them. The transmissive liquid crystal panels 22R, 22G, and 22B are imagers that respectively form image light of a first color, a second color, and a third color. The transmissive liquid crystal panel 22 includes a plurality of pixels arranged in a matrix along the XY plane. As shown in FIG. 3, the first light source 10R and the first transmissive liquid crystal panel 22R function as a first image light emitting device that emits first image light ML(R), which is a first color component of the image light ML. Similarly, the second light source 10G and the second transmissive liquid crystal panel 22G function as a second image light emitting device that emits second image light ML(G), which is a second color component of the image light ML. Furthermore, the third light source 10B and the third transmissive liquid crystal panel 22B function as a third image light emitting device that emits third image light ML(B), which is a third color component of the image light ML.

[0014] Returning to FIG. 2 , the imaging system 50 is disposed on the face side, i.e., the -Z side, of the display 40 or the display member 20, covering the eyes. The imaging 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 optical elements that constitute the imaging system 50, 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 system 50 and enables the imaging system 50 to be made thinner. Incidentally, even when 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 elements can be integrated by directly fixing them with an adhesive, or by closely adhering them to one another 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 system 50 is a dynamic optical element whose function changes depending on the state of the switching half-wave plate 55. The imaging system 50 functions as a lens for the image light ML emitted from the display member 20. In other words, the imaging system 50 comprehensively forms an image of multiple pixels included in the transmissive liquid crystal panels 22R, 22G, and 22B, making it possible to observe the image formed on the transmissive liquid crystal panels 22R, 22G, and 22B as a virtual image. On the other hand, the imaging system 50 functions as a parallel plate for the external light OL passing through the display member 20. In other words, the external light OL is observed as a direct-view image by passing through the display member 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 showing the optical unit 100 of the display optical systems 103a and 103b, and Fig. 4 is a view of the optical unit 100 seen from another direction. In Fig. 4, 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.

[0019] The optical unit 100 comprises a display 40 that emits image light ML and transmits external light OL, an imaging 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.

[0020] In imaging system 50, first polarizing diffractive lens 51 functions alone as a positive lens when predetermined circularly polarized light is incident, and second polarizing diffractive lens 52 also functions alone as a positive lens when predetermined circularly polarized light is incident. Switching half-wave plate 55 can be switched between an ON state and an OFF state, and when switching half-wave plate 55 is in the ON state, it causes polarizing diffractive lenses 51 and 52 to both function as positive lenses, and when switching half-wave plate 55 is in the OFF state, it cancels out the powers of polarizing diffractive lenses 51 and 52 and causes them to function like parallel flat plate glass.

[0021] FIG. 5 is a diagram illustrating the functions of the first polarized diffractive lens 51 and the second polarized diffractive lens 52. In FIG. 5, 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. 5, 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. 3 are the first type of polarized diffractive lens GP1.

[0022] As shown in the first region CR1 of FIG. 5, when collimated right-handed circularly polarized light RCP, such as light ray L1 shown by the solid line, enters 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 the light to focus at the focal point FP. Also, as shown in the second region CR2 of FIG. 5, when collimated left-handed circularly polarized light LCP, such as light ray L1 shown by the solid line, enters the polarized diffractive lens GP1 from the left side of the drawing, it converts the left-handed circularly polarized light LCP into right-handed circularly polarized light RCP and diverges the light. Also, as shown in the first region CR1 of FIG. 5, when right-handed circularly polarized light RCP, such as light ray L2 shown by the two-dot chain line, diverging from the focal point FP' on the left side of the drawing, enters the polarized diffractive lens GP1, it converts the right-handed circularly polarized light RCP into left-handed circularly polarized light LCP and collimates the light. 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. 5, the polarized diffractive lens GP1 functions as a negative lens with the same absolute focal length as the left-handed circularly polarized light LCP, while reversing the direction of rotation of the polarized light. In other words, the polarized diffractive lens GP1 is an optical element that has positive power for right-handed circularly polarized light RCP and negative power for left-handed circularly polarized light LCP.

[0023] As shown in the third region CR3 of FIG. 5, when collimated right-handed circularly polarized light RCP, such as the light ray L1 shown by the 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. Also, as shown in the fourth region CR4 of FIG. 5, when collimated left-handed circularly polarized light LCP, such as the light ray L1 shown by the 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. Also, as shown in the third region CR3 of FIG. 5, 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.

[0024] 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.

[0025] 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 polarized diffractive lenses GP1 themselves are known technology, such as polarization-dependent liquid crystal Fresnel lenses (see, for example, Kohei Noda, et al., Applied Optics, February 10, 2017, Vol. 56, No. 5: 1302).

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 3 , 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. 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 (RCP), 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.

[0030] 5, and when the image light ML and external light OL incident from the display 40 are right-handed circularly polarized light RCP, the first polarizing 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 polarizing diffractive lens 51 are incident on the switching half-wave plate 55 in the state of left-handed circularly polarized light LCP.

[0031] 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.

[0032] During the image observation period, the switching half-wave plate 55, in its ON state, converts the incident image light ML 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 the first region CR1 and the second region CR2 of FIG. 5. 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). The absolute values ​​of the powers of the first polarizing diffractive lens 51 and the second polarizing diffractive lens 52 are set equal, and the composite focal length of the 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 surfaces 11R, 11G, and 11B of transmissive liquid crystal panels 22R, 22G, and 22B included in display 40, imaging system 50 functions as a collimator, collimating and focusing image light ML at pupil position PP. Although Fig. 4 shows only the chief ray of image light ML from display surfaces 11R, 11G, and 11B, it can be seen that image light ML from diagonal positions on display surfaces 11R, 11G, and 11B passes through pupil position PP.

[0033] On the other hand, during the external light observation period, the switching half-wave plate 55 in the OFF state maintains the incident external light OL as left-handed circularly polarized light (LCP) and allows it to enter the second polarizing diffractive lens 52. The second polarizing diffractive lens 52 is the polarizing diffractive lens GP1 shown in the first region CR1 and the second region CR2 of FIG. 5. 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 combined 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 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.

[0034] As described above, during the image observation period, imaging system 50 has positive power due to switching half-wave plate 55 in the ON state, making it possible to observe image light ML, and during the external light observation period, imaging system 50 has substantially zero power due to switching half-wave plate 55 in the OFF state, making it possible to observe external light OL. In other words, virtual image display devices 100A, 100B or display optical systems 103a, 103b that perform such display enable a see-through display in which image light ML and external light OL are superimposed in a time-division manner.

[0035] Referring to Figure 6, 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 the transmissive liquid crystal panels 22R, 22G, and 22B, respectively.

[0036] 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, which emits light with shorter wavelengths (e.g., the blue 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, which emits light with longer wavelengths (e.g., the red component of the image light ML), is set shorter. Furthermore, the distance DG between the second color transmissive liquid crystal panel 22G that emits light having an intermediate wavelength, for example, the green component of the image light ML, and the polarizing diffraction lens 51 is set to an intermediate length.

[0037] 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 greater 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 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.

[0038] 6, 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 the area AR1), the size of the pixels included in the display area 12R of the first-color transmissive liquid crystal panel 22R is reduced to 94% (13R / 13G = 94% in the area AR2) based on the position and size of the second-color transmissive liquid crystal panel 22G. 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 the area AR1), the size of the pixels included in the third-color transmissive liquid crystal panel 22B is expanded to 111% (13B / 13G = 111% in the area AR2). 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.

[0039] 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, as shown in Fig. 7. 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 system 50 may also be fixed and integrated.

[0040] 8 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 first blinking signal SS1 from the first light source 10R of the first color (e.g., red), a first drive signal SM1 for displaying the first color that is applied to the transmissive liquid crystal panel 22R of the first color, a second blinking signal SS2 from the second light source 10G of the second color (e.g., green), a second drive signal SM2 for displaying the second color that is applied to the transmissive liquid crystal panel 22G of the second color, a third blinking signal SS3 from the third light source 10B of the third color (e.g., blue), a third drive signal SM3 for displaying the third color that is applied to the transmissive liquid crystal panel 22B of the third color, 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 operation 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 panels 22R, 22G, and 22B, respectively, and outputs an on-off signal SW to control the operation of the switching half-wave plate 55.

[0041] 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 illumination light of the first color, and the first-color transmissive liquid crystal panel 22R is in the display state, the first virtual image display device 100A displays a first image light ML(R), which is the first-color component of 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 illumination light of the second color, and the second-color transmissive liquid crystal panel 22G is in the display state, the first virtual image display device 100A displays a second image light ML(G), which is the second-color component of 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 illumination light of the third color, and the third-color transmissive liquid crystal panel 22B is in a display state, the first virtual image display device 100A displays the third image light ML(B), which is the third-color component of 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 states of the subframes ZR, ZG, and ZB, which display the three color components included in the image light ML one by one in a time-division manner.

[0042] In the first subframe ZR, the second light source 10G and the third light source 10B are in a transmissive state in which they do not emit illumination light, and the second-color transmissive liquid crystal panel 22G and the third-color transmissive liquid crystal panel 22B are in a non-display state in which they do not form image light ML(G), ML(B), and transmit the first-color illumination light emitted by the first light source 10R.Therefore, of the image light ML, the second image light ML(G), which is the second-color component, and the third image light ML(B), which is the third-color component, are not displayed. Similarly, in the second subframe ZG, the first light source 10R is in a transmissive state in which it does not emit illumination light and transmits the second color illumination light emitted by the second light source 10G, the third light source 10B is in a transmissive state in which it does not emit illumination light, the first color transmissive liquid crystal panel 22R is in a non-display state in which it does not form 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 in which it does not form image light ML(B), so that of the image light ML, the first color component, the first image light ML(R), and the third color component, the third image light ML(B), are not displayed. In addition, in the third subframe ZB, the first light source 10R and the second light source 10G are in a transmissive state in which they do not emit illumination light and transmit the third color illumination light 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 in which 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, so that of the image light ML, the first color component of the first image light ML(R) and the second color component of the second image light ML(G) are not displayed.

[0043] 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 in which they do not emit illumination light, 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 in which light is transmitted as is, 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 observation period as the subframe ZO.

[0044] A modified example of this embodiment will be described with reference to Fig. 9. Fig. 9 is a diagram illustrating display optical systems 103a and 103b of this modified example, and corresponds to Fig. 3. The configuration of Fig. 9 is the same as that of Fig. 3, 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. 5 are replaced with the polarizing diffractive lens GP2 shown in Fig. 5. 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.

[0045] In the imaging 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 5, 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.

[0046] During the image observation period, 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, because imaging system 50 has positive power, it becomes possible to observe the image light ML.

[0047] 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, where it is 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 device 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 system 50 has no power, it becomes possible to observe external light OL.

[0048] In the above description, the display 40 incorporates transmissive liquid crystal panels 22R, 22G, and 22B. However, other types of imagers, such as self-luminous organic EL (organic electroluminescence) displays, can be used instead of the transmissive liquid crystal panels 22R, 22G, and 22B. In this case, the light sources 10R, 10G, and 10B shown in FIG. 2 and elsewhere may be omitted. However, it is desirable that the imager of the organic EL display blocks external light OL while an image is being displayed and transmits external light OL while the image display is stopped.

[0049] The virtual image display devices 100A, 100B or the optical unit 100 according to the first embodiment described above include a light source 10B and a transmissive liquid crystal panel 22B as a third image light output device that outputs third image light of a third color in a subframe ZB as a third state, and a light source 10G and a transmissive liquid crystal panel 22G as a second image light output device that is disposed opposite the third image light output device and that outputs second image light of a second color in a subframe ZG as a second state and transmits the third image light in states other than the second state, and are disposed opposite the third image light output device and the second image light output device. The image light emitting device includes a first polarized diffractive lens 51 having positive power for the third image light and the second image light having circular polarization, a second polarized diffractive lens 52 having positive power for the third image light and the second image light that are incident through the first polarized diffractive lens 51 and have circular polarization, and a control device 80 that controls the third image light emitting device and the second image light emitting device to switch between the third state and the second state, wherein the third wavelength of the third color is shorter than the second wavelength of the second color, and the third dimension of each of the plurality of third pixels included in the third image light emitting device is larger than the second dimension of each of the plurality of second pixels included in the second image light emitting device.

[0050] In the virtual image display devices 100A, 100B or the optical unit 100, a first polarizing diffractive lens 51 having a positive power for image light having a first circular polarization and a second polarizing diffractive lens 52 having a positive power for image light having a second circular polarization after passing through the first polarizing diffractive lens 51 are combined to realize an imaging system 50 that is relatively thin and has a relatively short focal length. Furthermore, in the virtual image display devices 100A, 100B or the optical unit 100, the plurality of image light emitting devices that respectively emit a plurality of color components of the image light are disposed at different distances from the imaging system 50, thereby making it possible to correct chromatic aberration of the polarizing diffractive lenses 51, 52 included in the imaging system 50.

[0051] The virtual image display device 100A, 100B or the optical unit 100 further includes a switching half-wave plate disposed between the first polarizing diffractive lens 51 and the second polarizing diffractive lens 52, which operates as a half-wave plate that reverses the polarization rotation direction of circularly polarized light in the first state and the second state and transmits light in a fourth subframe ZO as a fourth state, the first image light output device and the second image light output device transmit external light OL in the fourth state, and a control device controls the first image light output device, the second image light output device, and the switching half-wave plate to switch between the first state, the second state, and the fourth state. Such a virtual image display device 100A, 100B or the optical unit 100 enables a see-through display in which the image light ML and the external light OL are superimposed in a time-division manner.

[0052] 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.

[0053] In the virtual image display device 100A, 100B or the optical unit 100 shown in FIG. 10 , the light sources 10R, 10G, and 10B and the transmissive liquid crystal panels 22R, 22G, and 22B do not transmit external light OL. Here, the light source 10B that is the outermost from the eye EY of the wearer US may be provided with a light-shielding film that blocks external light OL. As shown in FIG. 11 , when the virtual image display device 100A, 100B or the optical unit 100 according to this embodiment operates, the control device 80 controls the light sources 10R, 10G, and 10B and the transmissive liquid crystal panels 22R, 22G, and 22B to omit the subframe ZO as the external light observation period and to repeat the states of the subframes ZR, ZG, and ZB of the image observation period. As a result, only the image light ML enters the imaging system 50.

[0054] 10, instead of the switching half-wave plate 55 shown in Fig. 3, a non-dynamic half-wave plate 255 that is kept in a constant state is disposed, and the image light ML that has passed through the first polarizing diffractive lens 51 and become left-handed circularly polarized light LCP is converted into right-handed circularly polarized light RCP. The first polarizing diffractive lens 51 and the second polarizing diffractive lens 52 are polarizing diffractive lenses GP1.

[0055] In this embodiment, the display 40 does not transmit external light OL, so the virtual image display devices 100A and 100B do not perform see-through display, but display only the virtual image formed by the display 40.

[0056] 5 can also be used as the first polarizing diffractive lens 51 and the second polarizing diffractive lens 52 in the imaging system 50. In this case, the polarization state of the image light ML is reversed to that shown in FIG. 10, but it is possible to make the image light ML of collimated right-handed circularly polarized light RCP incident on the pupil position PP.

[0057] In the virtual image display devices 100A and 100B of this embodiment, a half-wave plate 255 is disposed between the first polarizing diffractive lens 51 and the second polarizing diffractive lens 52. The half-wave plate 255 converts the image light ML, which has passed through the first polarizing diffractive lens 51 and converted from the first circularly polarized light (right-circularly polarized RCP) to the second circularly polarized light (left-circularly polarized LCP), back to the first circularly polarized light, i.e., right-circularly polarized RCP. In this case, the half-wave plate 255 allows the first circularly polarized light, i.e., right-circularly polarized RCP, to be incident on the second polarizing diffractive lens 52. Therefore, assuming that the first polarizing diffractive lens 51 and the second polarizing diffractive lens 52 are of the same type that exhibit similar power characteristics for right-circularly polarized RCP, the first polarizing diffractive lens 51 and the second polarizing diffractive lens 52 can function like positive lenses despite their plate shape. Furthermore, the light sources 10R, 10G, and 10B and the transmissive LCD panels 22R, 22G, and 22B configured in the same manner as in the first embodiment allow correction of chromatic aberration of the polarizing diffractive lenses 51 and 52 to be achieved in the same manner as in the first embodiment.

[0058] 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.

[0059] In a specific aspect, the virtual image display device includes a first image light output device that outputs first image light of a first color in a first state, a second image light output device that is disposed opposite the first image light output device, outputs second image light of a second color in a second state, and transmits the first image light in states other than the second state, a first polarized diffractive lens that is disposed opposite the first image light output device and the second image light output device, and has positive power with respect to the first image light and the second image light having circular polarization, and a first polarized diffractive lens that is disposed opposite the first image light output device and the second image light output device, with the first polarized diffractive lens sandwiched therebetween. and a second polarized diffractive lens arranged opposite the second image light-emitting device and having positive power for the first image light and the second image light which are incident through the first polarized diffractive lens and have circular polarization; and a control device which controls the first image light-emitting device and the second image light-emitting device to switch between a first state and a second state, wherein 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 image light-emitting device is larger than a second dimension of each of a plurality of second pixels included in the second image light-emitting device.

[0060] Specifically, in the virtual image display device of this embodiment, the difference between the first dimension and the second dimension offsets the difference in the distance of the first pixel and the second pixel to the first polarized diffractive lens, and the corresponding first pixel and second pixel have shapes that appear to overlap at the desired observation position.

[0061] 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 system with a relatively short focal length. Furthermore, by using an image light output device that is positioned 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.

[0062] In a specific embodiment of the virtual image display device, the first polarizing diffractive lens and the second polarizing diffractive lens have a refractive index anisotropy distribution formed in a plane, which generates a geometric phase corresponding to the lens shape for a predetermined circularly polarized light.

[0063] In a specific aspect, the virtual image display device further includes a third image light-emitting device arranged opposite the first image light-emitting device and the second image light-emitting device, emitting third image light of a third color in a third state and transmitting the first image light and the second image light in states other than the third state; the first polarized diffractive lens is further arranged opposite the third image light-emitting device and has positive power for the third image light having circular polarization; the second polarized diffractive lens is further arranged opposite the third image light-emitting device across the first polarized diffractive lens and has positive power for the third image light that enters through the first polarized diffractive lens and has circular polarization; the control device further controls the third image light-emitting device to switch between the first state, the second state, and the third state; the second wavelength is shorter than the third wavelength of the third color, and the second dimension is larger than each third dimension of a plurality of third pixels included in the third image light-emitting device.

[0064] In the above virtual image display device, the three color components of the image light are respectively emitted, and full-color image light can be formed by superimposing the components in a time-division manner using image light emission devices that are each located at a different distance from the polarizing diffractive lens.

[0065] In a specific aspect of the virtual image display device, the first image light output device, the second image light output device, and the third image light output device transmit external light in the fourth state, and the virtual image display device further includes a switching half-wave plate disposed between the first polarized diffractive lens and the second polarized diffractive lens, which operates as a half-wave plate that reverses the polarization rotation direction of circularly polarized light in the first state, the second state, and the third state, and transmits light in the fourth state, and the control device further controls the switching half-wave plate to switch between the first state, the second state, the third state, and the fourth state.

[0066] In the virtual image display device, by controlling each image output device to provide a time for transmitting external light, it is possible to realize a see-through display in which image light and external light are superimposed in a time-division manner.

[0067] In a specific aspect of the virtual image display device, the first image light output device includes a first light source that outputs first illumination light of a first color in a first state and a first transmissive imager that forms first image light corresponding to the first illumination light in the first state, each of the first light source and the first transmissive imager transmitting light in states other than the first state; the second image light output device includes a second light source that outputs second illumination light of a second color in a second state and a second transmissive imager that forms second image light corresponding to the second illumination light in the second state, each of the second light source and the second transmissive imager transmitting light in states other than the second state; the third image light output device includes a third light source that outputs third illumination light of a third color in a third state and a third transmissive imager that forms third image light corresponding to the third illumination light in the third state, each of the third light source and the third transmissive imager transmitting light in states other than the third state.

[0068] In the virtual image display device, a combination of a transmissive backlight and a transmissive imager can be used as each image light emitting device.

[0069] In a specific embodiment, the virtual image display device further includes a first polarizing plate disposed between the first light source, the second light source, and the third light source and the first transmissive imager, the second transmissive imager, and the third transmissive imager, for converting the polarization of the first illumination light, the second illumination light, and the third illumination light into a first linearly polarized light; a second polarizing plate disposed between the first transmissive imager, the second transmissive imager, and the first polarizing diffractive lens, for converting the first linearly polarized light into a second linearly polarized light; and a quarter-wave plate disposed between the first polarizing plate and the first polarizing diffractive lens, for converting the second linearly polarized light into circularly polarized light.

[0070] In a specific embodiment, the virtual image display device further includes a first spacer having a uniform first thickness, one surface fixed to the first surface of the first transmissive imager and the other surface fixed to the first surface of the second transmissive imager, and transmitting light; and a second spacer having a uniform second thickness, one surface fixed to the second surface of the second transmissive imager and the other surface fixed to the first surface of the third transmissive imager, and transmitting light.

[0071] In the virtual image display device, by fixing each transmissive imager with a spacer interposed therebetween, it is possible to stably maintain different distances between each transmissive imager and the polarization diffractive lens.

[0072] In a specific embodiment, the virtual image display device includes a first image light emitting device that includes a self-luminous first transmissive imager that forms and emits first image light in a first state and transmits light in states other than the first state, a second image light emitting device that includes a self-luminous second transmissive imager that forms and emits second image light in a second state and transmits light in states other than the second state, and a third image light emitting device that includes a self-luminous third transmissive imager that forms and emits third image light in a third state and transmits light in states other than the third state.

[0073] In the virtual image display device, a self-luminous transmissive imager can be used as each of the image light emitting devices.

[0074] In a specific embodiment, the virtual image display device further includes a first polarizing plate disposed between the first transmissive imager, the second transmissive imager, and the third transmissive imager and the first polarizing diffractive lens, which converts the polarization of each of the first image light, the second image light, and the third image light into linearly polarized light, and a quarter-wave plate disposed between the first polarizing plate and the first polarizing diffractive lens, which converts the linearly polarized light into circularly polarized light.

[0075] In a specific embodiment, the virtual image display device further includes a first spacer having a uniform first thickness, one surface fixed to the first surface of the first transmissive imager and the other surface fixed to the first surface of the second transmissive imager, and transmitting light; and a second spacer having a uniform second thickness, one surface fixed to the second surface of the second transmissive imager and the other surface fixed to the first surface of the third transmissive imager, and transmitting light.

[0076] In a specific aspect, the optical unit includes a first image light output device that outputs first image light of a first color in a first state, a second image light output device that is disposed opposite the first image light output device, outputs second image light of a second color in a second state, and transmits the first image light in states other than the second state, a first polarized diffractive lens that is disposed opposite the first image light output device and the second image light output device, and has positive power with respect to the first image light and the second image light having circular polarization, and a first image light output device that is disposed opposite the first image light output device and the second image light output device, with the first polarized diffractive lens sandwiched therebetween. and a second polarized diffractive lens arranged opposite the second image light-emitting device and having positive power for the first image light and the second image light which are incident through the first polarized diffractive lens and have circular polarization; and a control device which controls the first image light-emitting device and the second image light-emitting device to switch between a first state and a second state, wherein 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 image light-emitting device is larger than a second dimension of each of a plurality of second pixels included in the second image light-emitting device.

[0077] In the optical unit, the two polarized diffractive lenses are both configured to have positive power with respect to the image light, enabling a relatively thin imaging system with a relatively short focal length. Furthermore, by using an image light output device that is positioned 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. [Explanation of symbols]

[0078] 10...light source member, 10R, 10G, 10B...light source, 11R, 11G, 11B...display surface, 12R, 12G, 12B...display area, 13R, 13G, 13B...dimensions, 14R, 14G, 14G...pixel, 20...display member, 21A, 21B...polarizing plate, 22R, 10G, 10B...transmissive liquid crystal panel, 23...quarter wave plate, 24A, 24B...spacer, 40...display, 50...imaging system, 51, 151...first polarized diffractive lens, 52, 152...second polarized diffractive lens, 55...switching half wave plate, 255...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... drive device, 102a, 102b... display drive unit, 103a, 103b... display optical system, 106... support device, 200... head-mounted display device, AX... optical axis, BL... backlight, DR, DG, DB, D1, D2... 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, ZR, ZG, ZB, ZO... subframe

Claims

1. a first image light emitting device that emits first image light of a first color in a first state; a second image light output device disposed opposite the first image light output device, the second image light output device outputting second image light of a second color in a second state and transmitting the first image light in states other than the second state; a first polarizing diffractive lens that is disposed opposite the first image light output device and the second image light output device and has a positive power with respect to the first image light and the second image light, each having circular polarization; a second polarizing diffractive lens that is disposed opposite the first image light output device and the second image light output device with the first polarizing diffractive lens interposed therebetween 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 control device that controls the first image light emitting device and the second image light emitting device to switch between the first state and the second state; Equipped with 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 image light-emitting device is larger than a second dimension of each of the plurality of second pixels included in the second image light-emitting device; Virtual image display device.

2. a difference between the first dimension and the second dimension offsets a difference in distance between the first pixel and the second pixel to the first polarized diffractive lens, and the corresponding first pixel and the second pixel have shapes that appear to overlap at a desired observation position. The virtual image display device according to claim 1 .

3. the first polarized diffractive lens and the second polarized diffractive lens have a refractive index anisotropy distribution formed in a plane, and generate a geometric phase corresponding to the lens shape for predetermined circularly polarized light; The virtual image display device according to claim 1 .

4. a third image light-emitting device disposed opposite the first image light-emitting device and the second image light-emitting device, emitting third image light of a third color in a third state and transmitting the first image light and the second image light in states other than the third state; Furthermore, the first polarized diffractive lens is further disposed opposite the third image light output device and has a positive power with respect to the third image light having circular polarization; the second polarizing diffractive lens is further disposed opposite the third image light output device with the first polarizing diffractive lens interposed therebetween, and has a positive power with respect to the third image light that has entered through the first polarizing diffractive lens and has circular polarization; the control device further controls the third image light emitting device to switch among the first state, the second state, and the third state; the second wavelength is shorter than the third wavelength of the third color; the second dimension is larger than a third dimension of each of a plurality of third pixels included in the third image light emitting device; The virtual image display device according to claim 1 .

5. the first image light output device, the second image light output device, and the third image light output device transmit external light in a fourth state; a switching half-wave plate disposed between the first polarizing diffractive lens and the second polarizing diffractive lens, which operates as a half-wave plate that reverses the polarization rotation direction of circularly polarized light in the first state, the second state, and the third state, and transmits light in the fourth state; Furthermore, the control device further controls the switching half-wave plate to switch between the first state, the second state, the third state, and the fourth state. The virtual image display device according to claim 4 .

6. the first image light emitting device, a first light source that emits first illumination light of the first color in the first state; a first transmissive imager that forms the first image light corresponding to the first illumination light in the first state; Equipped with each of the first light source and the first transmissive imager transmits light in a state other than the first state; the second image light emitting device, a second light source that emits second illumination light of the second color in the second state; a second transmissive imager that forms the second image light corresponding to the second illumination light in the second state; Equipped with each of the second light source and the second transmissive imager transmits light in a state other than the second state; the third image light emitting device, a third light source that emits third illumination light of the third color in the third state; a third transmissive imager that forms the third image light corresponding to the third illumination light in the third state; Equipped with each of the third light source and the third transmissive imager transmits light in a state other than the third state; 6. The virtual image display device according to claim 4 or 5.

7. a first polarizing plate disposed between the first light source, the second light source, and the third light source and the first transmissive imager, the second transmissive imager, and the third transmissive imager, and configured to convert the polarization of the first illumination light, the second illumination light, and the third illumination light into first linear polarization; a second polarizing plate disposed between the first transmissive imager, the second transmissive imager, and the third transmissive imager and the first polarizing diffractive lens, the second polarizing plate converting the first linearly polarized light into a second linearly polarized light; a quarter-wave plate disposed between the first polarizing plate and the first polarizing diffractive lens, and converting the second linearly polarized light into circularly polarized light; Further provided with The virtual image display device according to claim 6 .

8. a first spacer having a uniform first thickness, one surface of which is fixed to the first surface of the first transmissive imager and the other surface of which is fixed to the first surface of the second transmissive imager, and which transmits light; a second spacer having a uniform second thickness, one surface of which is fixed to the second surface of the second transmission imager and the other surface of which is fixed to the first surface of the third transmission imager, and which transmits light; Further provided with The virtual image display device according to claim 7 .

9. the first image light output device includes a first transmissive imager that is self-luminous and that generates and outputs the first image light in the first state and transmits light in states other than the first state; the second image light output device includes a second transmissive imager that is self-luminous and that generates and outputs the second image light in the second state and transmits light in states other than the second state; the third image light output device includes a self-luminous third transmissive imager that forms and outputs the third image light in the third state and transmits light in states other than the third state; 6. The virtual image display device according to claim 4 or 5.

10. a first polarizing plate disposed between the first transmissive imager, the second transmissive imager, and the third transmissive imager and the first polarized diffractive lens, the first polarizing plate converting the polarization of each of the first image light, the second image light, and the third image light into linearly polarized light; a quarter-wave plate disposed between the first polarizing plate and the first polarizing diffractive lens, and converting the linearly polarized light into circularly polarized light; Further provided with The virtual image display device according to claim 9 .

11. a first spacer having a uniform first thickness, one surface of which is fixed to a first surface of the first transmission imager and the other surface of which is fixed to a first surface of the second transmission imager; a second spacer having a uniform second thickness, one surface of which is fixed to the second surface of the second transmission imager and the other surface of which is fixed to the first surface of the third transmission imager; Further provided with The virtual image display device according to claim 10.

12. a first image light emitting device that emits first image light of a first color in a first state; a second image light output device disposed opposite the first image light output device, the second image light output device outputting second image light of a second color in a second state and transmitting the first image light in states other than the second state; a first polarizing diffractive lens that is disposed opposite the first image light output device and the second image light output device and has a positive power with respect to the first image light and the second image light, each having circular polarization; a second polarizing diffractive lens that is disposed opposite the first image light output device and the second image light output device with the first polarizing diffractive lens interposed therebetween 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 control device that controls the first image light emitting device and the second image light emitting device to switch between the first state and the second state; Equipped with 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 image light-emitting device is larger than a second dimension of each of the plurality of second pixels included in the second image light-emitting device; Optical unit.

Images