Virtual image display device

Abstract

To increase see-through transmittance in an image display area.SOLUTION: A virtual image display device 100A (100B) comprises: a light source 10; a light guide member 21; a ferroelectric liquid crystal plate 12 that is provided on the light guide member 21, and is in a scattering state where it emits illumination light IL to the outside of the light guide member 21 and a transparent state where it permits passage of external light OL; a transmission type liquid crystal panel 22 that is in a display state where it makes incident the illumination light IL passing through the ferroelectric liquid crystal plate 12 to form video light ML, or a non-display state where it transmits the external light OL passing through the ferroelectric liquid crystal plate 12; a switching 1 / 2 wavelength plate 23 that passes incident light, while switching the polarization direction of the incident light between a first direction and a second direction intersecting each other according to the alignment direction of liquid crystal; and a polarizing lens 50 that has refractive power to form first polarized light P1 in the first direction as a virtual image, and passes second polarized light P2 in the second direction.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a virtual image display device that enables observation of a virtual image, and particularly to a see-through type virtual image display device that enables visual recognition of an external image.

Background Art

[0002] As a see-through type virtual image display device that enables visual recognition of the outside world, there is known a liquid crystal panel having an image display area and a transparent display area formed so as to surround the image display area, and a light guide plate that guides backlight light incident from a light source to an end portion. The light guide plate includes a light emitting area that irradiates the image display area of the liquid crystal panel with backlight light and a light transmission area that transmits ambient light (Patent Document 1). In this virtual image display device, ambient light reaches the observer from the light transmission area of the light guide plate and the transparent display area of the liquid crystal panel, and during a period when the image display area is not irradiated with backlight light, the ambient light passes through the light emitting area of the light guide plate and the image display area of the liquid crystal panel and reaches the observer. With such a configuration, a see-through display in which video light and ambient light are superimposed is realized.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above device, processing such as dot formation and application of a scattering material is performed on the light emitting area of the light guide plate, and ambient light passing through the image display area of the liquid crystal panel passes through the processed light emitting area. Therefore, the see-through transmittance near the center of the visual field corresponding to the image display area decreases. In order to realize a see-through display with a high see-through transmittance near the center of the visual field, an optical system or the like with a high see-through transmittance is separately required, which leads to an increase in size.

Means for Solving the Problem

[0005] The virtual image display device according to one aspect of the present invention includes, in order from the outside world, a light guide member that propagates illumination light from a light source, a ferroelectric liquid crystal panel that is provided on the light guide member and is in a scattered state with respect to the illumination light and a transparent state with respect to external light, a transmissive liquid crystal panel that is in a display state and a non-display state, a switching 1 / 2 wavelength plate that switches the polarization direction of incident light to cross each other in a first direction and a second direction according to the liquid crystal alignment direction and allows it to pass through, and a polarization lens that has a refractive power to form an image of the polarization in the first direction as a virtual image and allows the polarization in the second direction to pass through. When the transmissive liquid crystal panel is in the display state, the switching 1 / 2 wavelength plate makes the video light from the transmissive liquid crystal panel enter the polarization lens as the polarization in the first direction, and when the transmissive liquid crystal panel is in the non-display state, makes the external light passing through the transmissive liquid crystal panel enter the polarization lens as the polarization in the second direction.

Brief Description of the Drawings

[0006]

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Mode for Carrying Out the Invention

[0007] 〔First Embodiment〕 Hereinafter, with reference to FIGS. 1 to 5, the virtual image display device according to the first embodiment of the present invention will be described.

[0008] FIG. 1 is a perspective view for explaining the wearing state of a head-mounted display, that is, a head-mounted display device 200. The head-mounted display device (hereinafter, also referred to as an HMD) 200 is a binocular display device 201, and causes an observer or wearer US wearing the same to recognize an image as a virtual image. In FIGS. 1 and the like, X, Y, and Z are orthogonal coordinate systems, the +X direction corresponds to the horizontal direction in which both eyes EY of the observer or wearer US wearing the HMD 200 are arranged, the +Y direction corresponds to the upward direction orthogonal to the horizontal direction in which both eyes EY are arranged for the wearer US, and the +Z direction corresponds to the forward direction or the front direction for the wearer US. The ±Y direction is parallel to the vertical axis or the vertical direction.

[0009] The HMD200 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 that support the virtual image display devices 100A and 100B, and a user terminal 90 that is an information terminal. The first virtual image display device 100A is composed of a first display driving unit 102a disposed at the upper part, a first display optical system 103a that covers in front of the eyes, and a light transmission cover 104a that covers the first display optical system 103a on the outside or front side. The second virtual image display device 100B is composed of a second display driving unit 102b disposed at the upper part, a second display optical system 103b that covers in front of the eyes, and a light transmission cover 104b that covers the second display optical system 103b on the outside or front side. The HMD200 that 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 is a wearing member or support device 106 that is worn on the head of the wearer US, and supports the upper end sides of the pair of display optical systems 103a and 103b and the upper end sides of the pair of light transmission covers 104a and 104b via the display driving units 102a and 102b that are integrated in appearance. The combination of the pair of display driving units 102a and 102b is called a driving device 102. The combination of the pair of light transmission covers 104a and 104b is called a shade 104.

[0010] FIG. 2 is a perspective view for explaining the structure of the first display optical system 103a. The first display optical system 103a includes a light source 10 that generates three-color light as illumination light in a time-division manner, a plate-shaped composite display member 20 that forms a two-dimensional image and emits image light ML, and a polarizing lens 50 that functions as a lens with respect to the image light ML. The light source 10 is also a part of the first display driving unit 102a shown in FIG. 1, and is arranged in the vicinity above the upper side of the light guide member 21 so as to supply illumination light from the upper end side to the light guide member 21, which will be described later, among the composite display members 20. The light source 10 and the composite display member 20 are driven by a drive circuit 81 of a control device 80 incorporated in the first display driving unit 102a to operate, and simultaneously realize the observation of a virtual image by the image light ML and see-through vision of the outside world. The composite display member 20 and the polarizing lens 50 are arranged at a distance in the optical axis AX direction. In the first display optical system 103a, the distance between the eye EY and the polarizing lens 50 is, for example, about 10 mm to 20 mm. Also, the distance between the composite display member 20 and the polarizing lens 50 is, for example, about 3 mm to 25 mm.

[0011] The light source 10 includes an R light-emitting element 10r that generates red light, a B light-emitting element 10b that generates blue light, and a G light-emitting element 10g that generates green light. The R light-emitting element 10r, the B light-emitting element 10b, and the G light-emitting element 10g are self-luminous elements, and may be, for example, light-emitting diodes such as organic light-emitting diodes (OLEDs) and micro light-emitting diodes (μLEDs) formed of inorganic materials. The R light-emitting element 10r, the B light-emitting element 10b, and the G light-emitting element 10g are not limited to being incorporated individually. That is, the light source 10 is a combination of one or more R light-emitting elements 10r, one or more B light-emitting elements 10b, and one or more G light-emitting elements 10g. A multiplexer / demultiplexer including a beam splitter can be incorporated between the light source 10 and the light guide member 21 of the composite display member 20 to assist in the diffusion of the illumination light.

[0012] The composite display member 20 is a plate-shaped member extending along the XY plane perpendicular to the optical axis AX, and includes, in order from the outside world, a light guide member 21, a transmissive liquid crystal panel 22, and a switching 1 / 2 wavelength plate 23. The composite display member 20 is a plate-shaped member as a whole in which the light guide member 21, the transmissive liquid crystal panel 22, and the switching 1 / 2 wavelength plate 23 are laminated, and has a structure integrated by a frame body (not shown). Here, the light guide member 21, the transmissive liquid crystal panel 22, and the switching 1 / 2 wavelength plate 23 are fixed to each other in a state where they are arranged in the vicinity with a predetermined interval. The transmissive liquid crystal panel 22 includes a plurality of pixels PX (see FIG. 3) arranged in a matrix along the XY plane.

[0013] The polarizing lens 50 is arranged on the front side of the composite display member 20, that is, the -Z side, and covers in front of the eyes. More specifically, the polarizing lens 50 is arranged on the opposite side of the transmissive liquid crystal panel 22 facing the switching 1 / 2 wavelength plate 23 in the composite display member 20. The polarizing lens 50 is a plate-shaped member extending along the XY plane. The action of the polarizing lens 50 varies according to the polarization direction of the incident light. The polarizing lens 50 functions as a lens with respect to the video light ML emitted from the composite display member 20. That is, the polarizing lens 50 comprehensively forms an image of a plurality of pixels constituting the transmissive liquid crystal panel 22, and enables the image formed on the transmissive liquid crystal panel 22 to be observed as a virtual image. On the other hand, the polarizing lens 50 functions as a parallel plate with respect to the external light OL passing through the composite display member 20. Specifically, the polarizing lens 50 is a liquid crystal lens and includes a plurality of circular annular portions RA having different refractive index states. A group of annular portions RA are symmetrically and concentrically arranged around the optical axis AX. Among the group of annular portions RA, the peripheral annular portion RA away from the optical axis AX has a narrower radial width centered on the optical axis AX than the central annular portion RA through which the optical axis AX passes. That is, the radial width of the annular portion RA becomes narrower as it is closer to the periphery.

[0014] The second display optical system 103b is optically identical to the first display optical system 103a, or is obtained by horizontally inverting the first display optical system 103a, and a detailed description thereof is omitted.

[0015] Referring to FIG. 3, the light source 10 generates three-color illumination lights ILr, ILg, and ILb as illumination light IL in a time-division manner, and supplies the three-color illumination lights ILr, ILg, and ILb to the light guide member 21 of the composite display member 20. The three-color illumination lights IL are selected to become white light when overlapped.

[0016] The light guide member 21 is formed by fixing the ferroelectric liquid crystal panel 12 to the light guide plate 11. The illumination lights ILr, ILg, and ILb from the light source 10 are coupled into the light guide plate 11 from the upper end of the light guide plate 11. The light guide plate 11 propagates the incident illumination lights ILr, ILg, and ILb from the light source 10 downward.

[0017] The light guide plate 11 is composed of a flat plate having light transmissivity and has a pair of planes 11a and 11b. On the plane 11b on the back side of the light guide plate 11, the ferroelectric liquid crystal panel 12 is attached in a state of being in close contact with the light guide plate 11 and fixed to the light guide plate 11. The ferroelectric liquid crystal panel 12 is provided in association with the light guide plate 11. That is, the ferroelectric liquid crystal panel 12 is provided in the light guide member 21 including the light guide plate 11. The ferroelectric liquid crystal panel 12 is a device that performs a switch-type operation in response to a drive signal from the drive circuit 81, and can be switched between a scattered state in which the illumination light IL (ILr, ILg, ILb) is emitted outside the light guide plate 11 and a transparent state in which the external light OL is transmitted and its passage is allowed. The ferroelectric liquid crystal panel 12 includes a ferroelectric liquid crystal layer 12a sandwiched between a pair of base materials 12b and 12c via a transparent electrode layer (not shown). The ferroelectric liquid crystal layer 12a is, for example, a reverse mode polymer dispersed liquid crystal, which becomes a transmissive state when no electric field is applied and becomes a scattered state when an electric field is applied (see, for example, Japanese Patent Laid-Open No. 6-308543, etc.). The ferroelectric liquid crystal panel 12 can be switched between ON and OFF not in pixel units but over the entire surface. When the ferroelectric liquid crystal panel 12 is in the OFF state, the ferroelectric liquid crystal panel 12 becomes a transparent state as a whole, allows the guiding of the illumination light IL in the light guide plate 11, and transmits and allows the passage of the external light OL incident on the ferroelectric liquid crystal panel 12 from the outside world through the light guide plate 11. On the other hand, when the ferroelectric liquid crystal panel 12 is in the ON state, the ferroelectric liquid crystal panel 12 becomes a scattered state as a whole, prevents total reflection of the illumination light IL in the light guide plate 11 and emits the illumination light IL outside the light guide plate 11, and restricts the passage of the external light OL incident on the ferroelectric liquid crystal panel 12 from the outside world through the light guide plate 11. Note that the ferroelectric liquid crystal layer 12a may be one that becomes a transmissive state when an electric field is applied and becomes a scattered state when no electric field is applied.

[0018] The transmissive liquid crystal panel 22 is disposed on the face side, i.e., the -Z side, facing the light guide plate 11 and the ferroelectric liquid crystal panel 12. The transmissive liquid crystal panel 22 includes a liquid crystal modulation member 14 and a pair of polarizing plates 15 and 16 sandwiching the liquid crystal modulation member 14. In this case, the transmissive liquid crystal panel 22 or the liquid crystal modulation member 14 is a modulation element made of, for example, an IPS (in plane switching) type liquid crystal and operates in units of pixels PX. The pixel PX has no filter and is colorless. The liquid crystal modulation member 14 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 15 and 16 are arranged such that the polarization directions intersect, more specifically, such that the polarization directions are orthogonal. That is, the video light ML or the external light OL emitted from the polarizing plate 16 after passing through the transmissive liquid crystal panel 22 has a first polarization P1 whose polarization direction is in the vertical first direction (see FIG. 4). The transmissive liquid crystal panel 22 can switch between ON and OFF in units of pixels PX according to a drive signal from the drive circuit 81, and can partially transmit incident light at an arbitrary gradation between ON and OFF. For this reason, the liquid crystal modulation member 14 includes not only a liquid crystal layer 31, a common electrode 32, a pixel electrode 33, and a black matrix 35, but also, although not shown, a scanning line, a signal line, a switching element, and the like.

[0019] Note that the transmissive liquid crystal panel 22 or the liquid crystal modulation member 14 may be one that rotates the polarization direction of incident light when no electric field is applied and does not rotate the polarization direction of incident light when an electric field is applied. In this case, the pair of polarizing plates 15 and 16 are arranged such that the polarization directions are parallel to each other.

[0020] The switching 1 / 2 wavelength plate 23 is disposed on the opposite side of the light guide plate 11 facing the transmissive liquid crystal panel 22. The switching 1 / 2 wavelength plate 23 is a device that performs a switching-type operation in response to a drive signal from the drive circuit 81, and switches and passes the polarization direction of incident light between a first direction and a second direction that intersect each other according to the alignment direction of the liquid crystal. The switching 1 / 2 wavelength plate 23 includes a liquid crystal layer 17a sandwiched between a pair of base materials 17b and 17c via a transparent electrode layer (not shown). The liquid crystal layer 17a is, for example, an in-plane switching (IPS) type liquid crystal or the like, which does not rotate the polarization direction of incident light when no electric field is applied, and rotates the polarization direction of incident light when an electric field is applied. The switching 1 / 2 wavelength plate 23 can switch ON and OFF over the entire surface rather than in pixel units. When the switching 1 / 2 wavelength plate 23 is in the OFF state, the switching 1 / 2 wavelength plate 23 functions as a transparent flat plate as a whole, and transmits the video light ML (that is, the first polarization P1 whose polarization direction is the vertical first direction, i.e., the ±Y direction) while maintaining its polarization direction (see the first region AR1 in FIG. 4). On the other hand, when the switching 1 / 2 wavelength plate 23 is in the ON state, the switching 1 / 2 wavelength plate 23 functions as a 1 / 2 wavelength plate having a main axis in the middle of the X direction and the Y direction as a whole, rotates the polarization direction of the external light OL (that is, the first polarization P1 whose polarization direction is the vertical first direction) by 90°, and emits it as the second polarization P2 whose polarization direction is the horizontal second direction (see the second region AR2 in FIG. 4).

[0021] The polarizing lens 50 disposed on the front face side of the switching 1 / 2 wavelength plate 23 includes a liquid crystal layer 18a sandwiched between a pair of base materials 18b and 18c via a transparent electrode layer (not shown). As described above, the liquid crystal layer 18a includes a number of circular ring-shaped portions RA (see FIG. 2) having different refractive index states around the optical axis AX along the XY plane. With respect to the first polarization P1 whose polarization direction is the vertical first direction parallel to the paper surface, that is, the ±Y direction, that is, with respect to the video light ML, the refractive index gradually decreases from the central ring-shaped portion RA through which the optical axis AX passes to the outer edge ring-shaped portion RA of the liquid crystal layer 18a, and it functions as a lens having positive power. Further, with respect to the second polarization P2 whose polarization direction is the horizontal second direction perpendicular to the paper surface, that is, the ±X direction, that is, with respect to the external light OL, the refractive index of each ring-shaped portion RA is uniform, and it functions as a parallel plate. As a result, the polarizing lens 50 has a refractive power for forming the first polarization P1 in the first direction as a virtual image, and allows the second polarization P2 in the second direction to pass through.

[0022] Hereinafter, with reference to FIG. 4, the state of light in the first display optical system 103a will be described. In FIG. 4, the first region AR1 shows the case where the first display optical system 103a is in the video observation period and the transmissive liquid crystal panel 22 is in the display state, and the second region AR2 shows the case where the first display optical system 103a is in the external light observation period and the transmissive liquid crystal panel 22 is in the non-display state. In the transmissive liquid crystal panel 22, the display state is a state in which illumination light IL passing through the ferroelectric liquid crystal panel 12 is incident to form video light ML, and the non-display state is a state in which external light OL passing through the ferroelectric liquid crystal panel 12 is transmitted.

[0023] In the first stage of the image observation period, among the light emitting elements 10r, 10g, and 10b of the light source 10, for example, the R light emitting element 10r emits light, and illumination light ILr which is red light is supplied to the light guide member 21. At this timing, when the ferroelectric liquid crystal panel 12 is switched to the ON state and becomes a scattering state, the illumination light ILr illuminates the liquid crystal modulation member 14 as the second polarization P2 which is horizontal polarization through the first polarizing plate 15 of the transmissive liquid crystal panel 22. That is, each colorless pixel PX constituting the transmissive liquid crystal panel 22 is illuminated. The video light QL that has passed through the liquid crystal modulation member 14 is the one obtained by rotating the polarization plane of the illumination light ILr according to the drive signal, and only the first polarization P1 which is vertical polarization is emitted as the video light ML(R) through the second polarizing plate 16. The video light ML(R) emitted from each pixel PX of the transmissive liquid crystal panel 22 is incident on the switching 1 / 2 wavelength plate 23. At this time, the switching 1 / 2 wavelength plate 23 is switched to the OFF state and functions like a transparent flat plate, and transmits the video light ML(R) of the first polarization P1 while maintaining its polarization direction. The video light ML(R) of the first polarization P1 that has passed through the switching 1 / 2 wavelength plate 23 forms a virtual image through the polarization lens 50 that functions as a convex lens with respect to the first polarization P1.

[0024] In the second stage of the image observation period, while maintaining the ferroelectric liquid crystal panel 12 in the ON state, the G light emitting element 10g of the light source 10 emits light instead of the R light emitting element 10r, and illumination light ILg which is green light is supplied to the light guide member 21 and is emitted laterally from the light guide member 21. The video light QL that passes through each pixel PX constituting the transmissive liquid crystal panel 22 or the liquid crystal modulation member 14 illuminated by the illumination light ILg is the one obtained by rotating the polarization plane of the illumination light ILg according to the drive signal, and each pixel PX of the transmissive liquid crystal panel 22 emits the video light ML(G) which is the first polarization P1. The switching 1 / 2 wavelength plate 23 is maintained in the OFF state, and the video light ML(G) of the first polarization P1 that has passed through the switching 1 / 2 wavelength plate 23 forms a virtual image through the polarization lens 50 that functions as a convex lens with respect to the first polarization P1.

[0025] In the third stage of the image observation period, while maintaining the ferroelectric liquid crystal panel 12 in the ON state, the B light emitting element 10b of the light source 10 emits light instead of the G light emitting element 10g, and illumination light ILb which is blue light is supplied to the light guide member 21 and is emitted laterally from the light guide member 21. The video light QL passing through each pixel PX constituting the transmissive liquid crystal panel 22 or the liquid crystal modulation member 14 illuminated by the illumination light ILb is the one obtained by rotating the polarization plane of the illumination light ILb according to the drive signal, and each pixel PX of the transmissive liquid crystal panel 22 emits the video light ML(B) which is the first polarization P1. The switching 1 / 2 wavelength plate 23 is maintained in the OFF state, and the video light ML(B) of the first polarization P1 passing through the switching 1 / 2 wavelength plate 23 forms a virtual image through the polarization lens 50 which functions as a convex lens with respect to the first polarization P1.

[0026] During the above image observation period, that is, when the transmissive liquid crystal panel 22 is in the display state, the three-color video lights ML(R), ML(G), and ML(B) are sequentially displayed, and the switching 1 / 2 wavelength plate 23 makes the first polarization P1 which is the video light ML from the transmissive liquid crystal panel 22 enter the polarization lens 50, and the wearer US recognizes a color image.

[0027] On one hand, during the external light observation period, the light source 10 is set to a non-light-emitting state, that is, the off state, and the supply of the illumination light IL to the light guide member 21 is stopped. At this timing, when the ferroelectric liquid crystal panel 12 is switched to the OFF state and becomes a transmissive state, the external light OL travels straight so as to intersect the light guide member 21 and enters the transmissive liquid crystal panel 22. At this time, each pixel PX of the transmissive liquid crystal panel 22 operates in, for example, a normally-off manner and is set to the maximum transmission state by a drive signal. Among the external light OL incident on the pixel PX of the transmissive liquid crystal panel 22, the second polarization P2 travels straight through the transmissive liquid crystal panel 22, that is, the pixel PX, and is converted into the first polarization P1 and enters the switching 1 / 2 wavelength plate 23. At this time, the switching 1 / 2 wavelength plate 23 is switched to the ON state and functions as a 1 / 2 wavelength plate, rotates the polarization direction of the external light OL that is the first polarization P1 by 90°, and emits it as the second polarization P2. That is, when the transmissive liquid crystal panel 22 is in the non-display state, the switching 1 / 2 wavelength plate 23 makes the external light OL that has passed through the transmissive liquid crystal panel 22 enter the polarization lens 50 as the second polarization P2. The external light OL of the second polarization P2 that has passed through the switching 1 / 2 wavelength plate 23 passes through the polarization lens 50 that functions as a parallel flat plate with respect to the second polarization P2 and enters the eye EY without undergoing an imaging effect by the composite display member 20 or the polarization lens 50.

[0028] FIG. 5 is a timing chart for explaining the display operation by the first virtual image display device 100A. The horizontal axis represents time. In order from the top, there are shown the blinking signal SS1 of the R light-emitting element 10r, the R drive signal SM1 for red display given to the liquid crystal modulation member 14, the blinking signal SS2 of the G light-emitting element 10g, the G drive signal SM2 for green display given to the liquid crystal modulation member 14, the blinking signal SS3 of the B light-emitting element 10b, the B drive signal SM3 for blue display given to the liquid crystal modulation member 14, the on / off signal SD of the ferroelectric liquid crystal panel (FLC) 12, and the on / off signal SW of the switching 1 / 2 wavelength plate (1 / 2λ) 23. The operation of the first virtual image display device 100A has, in each frame, a first sub-frame Z1 that is a sub-frame for video observation and a second sub-frame Z2 that is a sub-frame for external light observation.

[0029] In the red display section Δ1, which is the first stage of the first sub-frame Z1 for video observation, the drive circuit 81 turns on the ferroelectric liquid crystal panel 12, lights the R light-emitting element 10r, outputs an R drive signal SM1 for red display to each pixel PX of the transmissive liquid crystal panel 22, and turns off the switching 1 / 2 wavelength plate 23. As a result, red video light ML(R) is incident on the eye EY, and the polarizing lens 50 enables the observation of a virtual image corresponding to the red pattern formed on the transmissive liquid crystal panel 22. In the green display section Δ2, which is the second stage of the first sub-frame Z1, the drive circuit 81 maintains the ON state of the ferroelectric liquid crystal panel 12, lights the G light-emitting element 10g, outputs a G drive signal SM2 for green display to each pixel PX of the transmissive liquid crystal panel 22, and maintains the OFF state of the switching 1 / 2 wavelength plate 23. As a result, green video light ML(G) is incident on the eye EY, and the polarizing lens 50 enables the observation of a virtual image corresponding to the green pattern formed on the transmissive liquid crystal panel 22. In the blue display section Δ3, which is the third stage of the first sub-frame Z1, the drive circuit 81 maintains the ON state of the ferroelectric liquid crystal panel 12, lights the B light-emitting element 10b, outputs a B drive signal SM3 for blue display to each pixel PX of the transmissive liquid crystal panel 22, and maintains the OFF state of the switching 1 / 2 wavelength plate 23. As a result, blue video light ML(B) is incident on the eye EY, and the polarizing lens 50 enables the observation of a virtual image corresponding to the blue pattern formed on the transmissive liquid crystal panel 22.

[0030] During the above first sub-frame Z1, that is, the video observation period, the three-color video lights ML(R), ML(G), and ML(B) are sequentially displayed by the transmissive liquid crystal panel 22 in the display state or the transmissive state, and the wearer US recognizes a color image.

[0031] In the second sub-frame Z2 for external light observation, the drive circuit 81 sets the ferroelectric liquid crystal panel 12 to the OFF state to transmit the external light OL, turns off the light source 10, outputs, for example, a drive signal with maximum transmittance to each pixel PX of the transmissive liquid crystal panel 22, and sets the switching 1 / 2 wavelength plate 23 to the ON state. At this time, the transmissive liquid crystal panel 22 is in a non-display state and a transmissive state. As a result, the external light OL that travels straight through the transmissive liquid crystal panel 22 and the polarizing lens 50 enters the eye EY, enabling the observation of the external image.

[0032] The structure of the first embodiment described above is an example. For example, the transmissive liquid crystal panel 22 does not necessarily need to operate in the normally-off mode and may operate in the normally-on mode. When operating in the normally-on mode, the drive signals SM1, SM2, and SM3 shown in FIG. 5 are those with the phase relationship inverted, that is, those with the magnitude of the applied voltage inverted. The transmissive liquid crystal panel 22 is not limited to an IPS-type liquid crystal element and may be another type of liquid crystal display element such as a TN-type liquid crystal element.

[0033] The switching 1 / 2 wavelength plate 23 may be configured to rotate the polarization direction of the video light ML by 90° and emit it as the second polarization P2 while allowing the external light OL to pass through as the first polarization P1 while maintaining its polarization direction. In this case, the polarizing lens 50 has a refractive power to form an image of the video light ML of the second polarization P2 as a virtual image and allows the external light OL of the first polarization P1 to pass through as a parallel plate as it is. Note that the second polarization P2 that undergoes an imaging effect by such a polarizing lens 50 can be called the first polarization, and the first polarization P1 that does not undergo an imaging effect by this polarizing lens 50 can be called the second polarization.

[0034] The light guide member 21 is not limited to a structure in which the ferroelectric liquid crystal panel 12 is fixed to the eye EY side of the light guide plate 11 and may be a structure in which the ferroelectric liquid crystal panel 12 is fixed to the external side of the light guide plate 11.

[0035] The first sub-frame Z1 and the second sub-frame Z2 shown in FIG. 5 are merely examples, and the time width and time ratio of the sub-frames Z1 and Z2 can be adjusted according to the external environment by, for example, the control device 80, or can also be adjusted by the wearer US via the user terminal 90.

[0036] In the first sub-frame Z1, it is not necessary to set the pixels PX of the transmissive liquid crystal panel 22 to the maximum transmission state. By adjusting the transmittance of the pixels PX, the transmission intensity of the external light OL can be adjusted like a dimmable sunglass. At this time, the transmittance can be adjusted not for the entire surface of the transmissive liquid crystal panel 22 but for a local area.

[0037] The virtual image display devices 100A and 100B of the first embodiment described above include, in order from the outside world, a light guide member 21 that propagates the illumination light IL from the light source 10, a ferroelectric liquid crystal panel 12 provided on the light guide member 21 and being in a scattered state with respect to the illumination light IL and in a transparent state with respect to the external light OL, a transmissive liquid crystal panel 22 that becomes a display state and a non-display state, a switching 1 / 2 wavelength plate 23 that switches and passes the polarization direction of the incident light in the first direction and the second direction that cross each other according to the liquid crystal alignment direction, and a polarization lens 50 that has a refractive power to form an image of the first polarization P1 in the first direction as a virtual image and passes the second polarization P2 in the second direction. When the transmissive liquid crystal panel 22 is in the display state, the switching 1 / 2 wavelength plate 23 makes the video light ML from the transmissive liquid crystal panel 22 incident on the polarization lens 50 as the first polarization P1 in the first direction, and when the transmissive liquid crystal panel 22 is in the non-display state, makes the external light OL that has passed through the transmissive liquid crystal panel 22 incident on the polarization lens 50 as the second polarization P2 in the second direction.

[0038] In the above virtual image display device, when the transmissive liquid crystal panel 22 is in the display state, the switching 1 / 2 wavelength plate 23 makes the video light ML from the transmissive liquid crystal panel 22 incident on the polarizing lens 50 as the first polarization P1 in the first direction. When the transmissive liquid crystal panel 22 is in the non-display state, the external light OL passing through the transmissive liquid crystal panel 22 is made incident on the polarizing lens 50 as the second polarization P2 in the second direction. Therefore, it is possible to switch between the video light ML and the external light OL and observe them in parallel. That is, the transmissive liquid crystal panel 22 can be used for video observation and external light observation by using the ferroelectric liquid crystal panel 12, and it is possible to suppress a decrease in the see-through transmittance while ensuring the brightness of the display.

[0039] In the virtual image display devices 100A and 100B of the first embodiment, the light source 10 generates illumination light by switching among red, green, and blue. The transmissive liquid crystal panel 22 has colorless pixels PX, modulates according to the color of the illumination light generated by the light source 10 by the pixels PX, and makes the pixels PX in the transmissive state when the light source 10 is not emitting light. In this case, during the first sub-frame Z1 which is a sub-frame for video observation, there are display sections Δ1, Δ2, and Δ3 of respective colors for displaying the red, green, and blue video lights ML(R), ML(G), and ML(B).

[0040] 〔Second Embodiment〕 Hereinafter, the virtual image display device and the like of the second embodiment will be described. Note that the virtual image display device of the second embodiment is a partially modified version of the virtual image display device of the first embodiment, and descriptions of the parts common to the virtual image display device of the first embodiment will be omitted.

[0041] In the first display optical system 103a or the first virtual image display device 100A shown in FIG. 6, the transmissive liquid crystal panel 22 includes sub-pixels PXs, specifically, three types of sub-pixels PXs(R), PXs(G), and PXs(B). These sub-pixels PXs(R), PXs(G), and PXs(B) are arranged in a stripe shape or a Bayer shape (not shown) to form the pixel PX.

[0042] In the sub-pixels PXs(R) for red display, a red color filter 41r is disposed near the first polarizing plate 15. In the sub-pixels PXs(G) for green display, a green color filter 41g is disposed near the first polarizing plate 15. In the sub-pixels PXs(B) for blue display, a blue color filter 41b is disposed near the first polarizing plate 15.

[0043] Referring to FIG. 7, the state of light in the first display optical system 103a will be described. In FIG. 7, the first region BR1 shows the case where the first display optical system 103a is in the video observation period and the transmissive liquid crystal panel 22 is in the display state, and the second region BR2 shows the case where the first display optical system 103a is in the external light observation period and the transmissive liquid crystal panel 22 is in the non-display state.

[0044] During the video observation period, by causing all the light-emitting elements 10r, 10g, 10b constituting the light source 10 to emit light, white illumination lights ILr, ILg, ILb are supplied to the light guide member 21. At this timing, when the ferroelectric liquid crystal panel 12 is switched to the ON state and becomes the scattering state, among the illumination lights ILr, ILg, ILb, the second polarization P2 illuminates the sub-pixels PXs(R), PXs(G), PXs(B) constituting each pixel PX through the first polarizing plate 15 of the transmissive liquid crystal panel 22. As a result, the modulated ML(R), ML(G), ML(B) of the first polarization P1 are emitted in parallel from the transmissive liquid crystal panel 22. The video lights ML(R), ML(G), ML(B) emitted from the respective sub-pixels PXs(R), PXs(G), PXs(B) of the transmissive liquid crystal panel 22 enter the OFF-state switching 1 / 2 wavelength plate 23. The switching 1 / 2 wavelength plate 23 transmits the video lights ML(R), ML(G), ML(B) of the first polarization P1 while maintaining their polarization directions. The video lights ML(R), ML(G), ML(B) of the first polarization P1 that have passed through the switching 1 / 2 wavelength plate 23 form virtual images through the polarization lens 50 that functions as a convex lens with respect to the first polarization P1.

[0045] On one hand, during the external light observation period, the light source 10 is set to a non-emitting state, that is, the lighting is turned off, and the supply of illumination light IL to the light guide member 21 is stopped. When the ferroelectric liquid crystal panel 12 is switched to the OFF state to be in a transmissive state, the external light OL travels straight through the light guide member 21 and enters the transmissive liquid crystal panel 22. At this time, the sub-pixels PXs(R), PXs(G), and PXs(B) that make up each pixel PX of the transmissive liquid crystal panel 22 are, for example, in the maximum transmission state. Among the external light OL, the second polarization P2 travels straight through the transmissive liquid crystal panel 22, that is, the sub-pixels PXs(R), PXs(G), and PXs(B), and is converted into the first polarization P1 and enters the switching 1 / 2 wavelength plate 23. The switching 1 / 2 wavelength plate 23 in the ON state rotates the external light OL of the first polarization P1 by 90° in its polarization direction and emits it as the second polarization P2. The external light OL of the second polarization P2 that has passed through the switching 1 / 2 wavelength plate 23 enters the eye EY without being subjected to an imaging effect by the composite display member 20 or the polarization lens 50 via the polarization lens 50 that functions as a parallel plate with respect to the second polarization P2.

[0046] FIG. 8 is a timing chart for explaining the display operation by the first virtual image display device 100A, corresponding to the timing chart shown in FIG. 5 of the first embodiment. In this case, instead of sequentially displaying the three-color video lights ML(R), ML(G), and ML(B) in a time division manner, the three-color video lights ML(R), ML(G), and ML(B) are displayed simultaneously in parallel. When the first virtual image display device 100A is in the external light observation period and the transmissive liquid crystal panel 22 is in a non-display state, the external light OL evenly passes through the sub-pixels PXs(R), PXs(G), and PXs(B) of the transmissive liquid crystal panel 22, enabling the observation of an external image without coloring.

[0047] Also in this embodiment, the switching 1 / 2 wavelength plate 23 may be configured to rotate the polarization direction of the video light ML by 90° and emit it as the second polarization P2 while allowing the external light OL to pass through as the first polarization P1 while maintaining its polarization direction. Also, the time widths and time ratios of the sub-frames Z1 and Z2 can be adjusted according to the external environment by, for example, the control device 80.

[0048] In the second sub-frame Z2 which is a sub-frame for external light observation, it is not necessary to set each sub-pixel PXs(R), PXs(G), PXs(B) that constitutes the transmissive liquid crystal panel 22 to the maximum transmission state, and the transmittance of each sub-pixel PXs(R), PXs(G), PXs(B) can be adjusted individually.

[0049] In the virtual image display devices 100A and 100B of the second embodiment, the light source 10 generates white illumination lights ILr, ILg, and ILb, the transmissive liquid crystal panel 22 has red, green, and blue sub-pixels PXs(R), PXs(G), and PXs(B), modulation is performed by the sub-pixels PXs(R), PXs(G), and PXs(B) of each color in accordance with the light emission of the light source 10, and each sub-pixel PXs(R), PXs(G), and PXs(B) of each color is in a transmissive state when the light source 10 is not emitting light. In this case, in the first sub-frame Z1 which is a sub-frame for video observation, red, green, and blue video lights ML can be simultaneously displayed.

[0050] 〔Third Embodiment〕 Hereinafter, the virtual image display device and the like of the third embodiment will be described. Note that the virtual image display device of the third embodiment is a partially modified version of the virtual image display device of the first embodiment, and descriptions of the parts common to the virtual image display device of the first embodiment will be omitted.

[0051] In the first display optical system 103a or the first virtual image display device 100A shown in FIGS. 9 and 10, the transmissive liquid crystal panel 22 includes two types of pixels PX(D) and PX(T). The pixels PX(D) and PX(T) both do not have color filters and are colorless. One display pixel PX(D) is a part for forming the video light ML, and the other transmissive pixel PX(T) is for external light OL and enables the external light OL to be seen through.

[0052] For example, as shown in FIG. 11, the colorless pixels PX(D) and PX(T) can be arranged alternately in a checkerboard pattern, but it is not limited thereto, and as long as the rows of the display pixels PX(D) and the rows of the transmissive pixels PX(T) are alternately repeated.

[0053] During the video observation period shown in FIG. 9, each of the light emitting elements 10r, 10g, 10b constituting the light source 10 emits light sequentially, and illumination lights ILr, ILg, ILb of respective colors are supplied to the light guide member 21. At this time, the ferroelectric liquid crystal panel 12 is in the ON state and in the scattering state, and the second polarization P2 among the illumination lights ILr, ILg, ILb illuminates each display pixel PX(D) through the first polarizing plate 15 of the transmissive liquid crystal panel 22. As a result, modulated ML(R), ML(G), ML(B) of the first polarization P1 are sequentially emitted from the transmissive liquid crystal panel 22 at different timings in time series. However, the transmissive pixel PX(T) is in the OFF state and does not transmit the illumination light. The video lights ML(R), ML(G), ML(B) emitted from each display pixel PX(D) of the transmissive liquid crystal panel 22 are incident on the OFF-state switching 1 / 2 wavelength plate 23. The switching 1 / 2 wavelength plate 23 sequentially transmits the video lights ML(R), ML(G), ML(B) of the first polarization P1 while maintaining their polarization directions. The video lights ML(R), ML(G), ML(B) of the first polarization P1 that have sequentially passed through the switching 1 / 2 wavelength plate 23 at different timings in time series form virtual images through the polarization lens 50 that functions as a convex lens with respect to the first polarization P1.

[0054] On the other hand, during the external light observation period shown in FIG. 10, when the light source 10 is in the non-light emitting state, that is, the light-off state, the supply of the illumination light IL to the light guide member 21 is stopped, and the ferroelectric liquid crystal panel 12 is switched to the OFF state to be in the transmissive state, the external light OL travels straight so as to intersect the light guide member 21 and is incident on the transmissive liquid crystal panel 22. At this time, the display pixel PX(D) and the transmissive pixel PX(T) of the transmissive liquid crystal panel 22 are, for example, in the maximum transmissive state, and the second polarization P2 among the external lights OL travels straight through the transmissive liquid crystal panel 22, that is, the pixels PX(D), PX(T), is converted into the first polarization P1, and is incident on the switching 1 / 2 wavelength plate 23. The ON-state switching 1 / 2 wavelength plate 23 rotates the polarization direction of the external light OL of the first polarization P1 by 90° and emits it as the second polarization P2. The external light OL of the second polarization P2 that has passed through the switching 1 / 2 wavelength plate 23 is incident on the eye EY without being subjected to an imaging action by the composite display member 20 or the polarization lens 50 through the polarization lens 50 that functions as a parallel plate with respect to the second polarization P2.

[0055] FIG. 12 is a timing chart for explaining the display operation by the first virtual image display device 100A. FIG. 12 is obtained by adding a W drive signal SM4 for the pixel PX(T) to the drive signal similar to that in FIG. 5.

[0056] FIG. 13 is a modification of the first display optical system 103a shown in FIG. 9 and the like, and the ferroelectric liquid crystal panel 12 has a stripe-shaped effective region 51. The effective region 51 is not uniformly formed on the light guide plate 11 or the light guide member 21, but is formed to face only the display pixel PX(D). The effective region 51 has a ferroelectric liquid crystal layer 12a (see FIG. 3) and can scatter the illumination lights ILr, ILg, and ILb. On the other hand, the transmission region 52 formed between the effective regions 51 does not have a ferroelectric liquid crystal layer 12a and allows the external light OL to travel straight and transmit without scattering.

[0057] As shown in FIG. 14, the transmissive liquid crystal panel 22 has a stripe arrangement in which the rows of the display pixels PX(D) and the rows of the transmissive pixels PX(T) are alternately repeated. Correspondingly, the ferroelectric liquid crystal panel 12 also has a stripe arrangement in which the effective regions 51 facing the rows of the display pixels PX(D) and the transmission regions 52 facing the rows of the transmissive pixels PX(T) are alternately repeated. Note that the rows of the pixels PX(D) and PX(T) are exemplified as extending in the horizontal direction or the X direction, but are not limited to those extending in the horizontal direction or the X direction, and may extend in the vertical direction or the Y direction.

[0058] In the virtual image display devices 100A and 100B according to the third embodiment, the light source 10 generates illumination light ILr, ILg, and ILb of red, green, and blue by switching. The transmissive liquid crystal panel 22 has colorless display pixels PX(D) and colorless transmissive pixels PX(T). Modulation is performed by the colorless display pixels PX(D) according to the color of the illumination light ILr, ILg, and ILb generated by the light source 10, and the colorless transmissive pixels PX(T) are in a transmissive state when the light source 10 is not emitting light. In this case, in the first sub-frame Z1, which is a sub-frame for observing video, there are display sections Δ1, Δ2, and Δ3 for displaying video light ML(R), ML(G), and ML(B) of red, green, and blue. In the second sub-frame Z2, which is a sub-frame for observing external light, by operating at least the colorless transmissive pixels PX(T), it becomes possible to observe a color video and a see-through image in a time-division manner.

[0059] In the virtual image display device 100A of the modified example shown in FIG. 13, the transmissive liquid crystal panel 22 has the colorless display pixels PX(D) in a transmissive state when the light source 10 is not emitting light. In this case, in the second sub-frame Z2, which is a sub-frame for observing external light, the display pixels PX(D) can be utilized, and the see-through image can be brightened.

[0060] In the virtual image display device 100A of the modified example shown in FIG. 13, the effective region 51 of the ferroelectric liquid crystal panel 12 is locally formed in a region facing the colorless display pixels PX(D) of the transmissive liquid crystal panel 22. For the colorless transmissive pixels PX(T), it is not necessary to scatter the external light OL. By simply locally forming the effective region 51 of the ferroelectric liquid crystal panel 12 in a region facing the colorless display pixels PX(D), the illumination light ILr, ILg, and ILb can be selectively incident on the colorless display pixels PX(D).

[0061] 〔Fourth Embodiment〕 Hereinafter, the virtual image display device and the like according to the fourth embodiment will be described. The virtual image display device according to the fourth embodiment is a partially modified version of the virtual image display device according to the second embodiment, and descriptions of parts common to the virtual image display device according to the second embodiment will be omitted.

[0062] In the first display optical system 103a or the first virtual image display device 100A shown in FIGS. 15 and 16, the transmissive liquid crystal panel 22 includes sub-pixels PXs, specifically, four types of sub-pixels PXs(R), PXs(G), PXs(B), and PXs(T). Three types of sub-pixels PXs(R), PXs(G), and PXs(B) all have color filters 41r, 41g, and 41b and are for image light ML. The remaining one type of sub-pixel PXs(T) has no color filter and is for external light OL.

[0063] Referring to FIG. 17, the arrangement of the sub-pixels PXs will be described. In FIG. 17, the first region CR1 shows an example of the arrangement of the sub-pixels PXs, and the second region CR2 shows another example of the arrangement of the sub-pixels PXs. The four types of sub-pixels PXs(R), PXs(G), PXs(B), and PXs(T) are in an equal stripe-like arrangement, but they can also be arranged in a Bayer pattern.

[0064] During the video observation period shown in FIG. 15, by causing all the light emitting elements 10r, 10g, 10b constituting the light source 10 to emit light, white illumination lights ILr, ILg, ILb are supplied to the light guide member 21. At this timing, when the ferroelectric liquid crystal panel 12 is switched to the ON state and becomes a scattering state, the second polarization P2 among the illumination lights ILr, ILg, ILb illuminates the sub-pixels PXs(R), PXs(G), PXs(B), PXs(T) constituting each pixel PX through the first polarizing plate 15 of the transmissive liquid crystal panel 22. As a result, the modulated ML(R), ML(G), ML(B) of the first polarization P1 are emitted in parallel from the transmissive liquid crystal panel 22. However, the sub-pixel PXs(T) is in the OFF state and does not transmit the illumination light. The video lights ML(R), ML(G), ML(B) emitted from the respective sub-pixels PXs(R), PXs(G), PXs(B) of the transmissive liquid crystal panel 22 are incident on the OFF-state switching 1 / 2 wavelength plate 23. The switching 1 / 2 wavelength plate 23 transmits the video lights ML(R), ML(G), ML(B) of the first polarization P1 while maintaining their polarization directions. The video lights ML(R), ML(G), ML(B) of the first polarization P1 that have passed through the switching 1 / 2 wavelength plate 23 form virtual images through the polarization lens 50 that functions as a convex lens with respect to the first polarization P1.

[0065] On the one hand, during the external light observation period shown in FIG. 16, when the light source 10 is in a non-emitting state, that is, in a turned-off state, the supply of illumination light IL to the light guide member 21 is stopped, and the ferroelectric liquid crystal panel 12 is switched to the OFF state to be in a transmissive state. Then, the external light OL travels straight so as to intersect the light guide member 21 and enters the transmissive liquid crystal panel 22. At this time, the sub-pixels PXs(R), PXs(G), PXs(B), and PXs(T) that constitute each pixel PX of the transmissive liquid crystal panel 22 are driven, for example, to the maximum transmissive state. Among the external light OL, the second polarization P2 travels straight through the transmissive liquid crystal panel 22, that is, the sub-pixels PXs(R), PXs(G), PXs(B), and PXs(T), and is converted into the first polarization P1 and enters the switching 1 / 2 wavelength plate 23. The switching 1 / 2 wavelength plate 23 in the ON state rotates the external light OL of the first polarization P1 by 90° in its polarization direction and emits it as the second polarization P2. The external light OL of the second polarization P2 that has passed through the switching 1 / 2 wavelength plate 23 enters the eye EY without undergoing an imaging effect by the composite display member 20 or the polarization lens 50 via the polarization lens 50 that functions as a parallel plate with respect to the second polarization P2.

[0066] FIG. 18 is a modified example of the first display optical system 103a shown in FIG. 15 and the like, and the ferroelectric liquid crystal panel 12 has a stripe-shaped effective region 51. The effective region 51 is formed to face only the display sub-pixels PXs(R), PXs(G), and PXs(B) among the respective pixels PX. The effective region 51 has a ferroelectric liquid crystal layer 12a (see FIG. 3) and can scatter the illumination lights ILr, ILg, and ILb. On the other hand, the transmissive region 52 formed between the effective regions 51 does not have the ferroelectric liquid crystal layer 12a and allows the external light OL to travel straight and transmit without scattering it.

[0067] As shown in FIG. 19, the transmissive liquid crystal panel 22 has a stripe arrangement in which three rows of sub-pixels PXs(R), PXs(G), and PXs(B) and one row of sub-pixels PXs(T) are alternately repeated. Correspondingly, the ferroelectric liquid crystal panel 12 also has a stripe arrangement in which the effective regions 51 facing the three rows of sub-pixels PXs(R), PXs(G), and PXs(B) and the transmissive regions 52 facing the rows of sub-pixels PXs(T) are alternately repeated.

[0068] In the virtual image display devices 100A and 100B according to the fourth embodiment, the light source 10 generates white illumination lights ILr, ILg, and ILb, and the transmissive liquid crystal panel 22 has red, green, and blue sub-pixels PXs(R), PXs(G), PXs(B) and colorless sub-pixels PXs(T). Modulation is performed by the sub-pixels PXs(R), PXs(G), PXs(B) of each color in accordance with the light emission of the light source 10, and the colorless sub-pixel PXs(T) is in a transmissive state when the light source 10 is not emitting light. In this case, in the first sub-frame Z1 which is a sub-frame for video observation, red, green, and blue video lights ML(R), ML(G), ML(B) can be displayed simultaneously. In the second sub-frame Z2 which is a sub-frame for external light observation, by operating at least the colorless sub-pixel PXs(T), it becomes possible to observe in a time-division manner between a color video and a see-through image.

[0069] In the virtual image display device 100A of the modification shown in FIG. 18 etc., the transmissive liquid crystal panel 22 makes the sub-pixels PXs(R), PXs(G), PXs(B) of each color in a transmissive state when the light source 10 is not emitting light. In this case, in the second sub-frame Z2 which is a sub-frame for external light observation, the sub-pixels PXs(R), PXs(G), PXs(B) of each color can be utilized, and the see-through image can be brightened.

[0070] 〔Modification and Others〕 Although the present invention has been described in accordance with the above embodiments, the present invention is not limited to the above embodiments, and can be implemented in various aspects without departing from the gist thereof. For example, the following modifications are also possible.

[0071] The liquid crystal lens as the polarizing lens 50 is not limited to one including a ring-shaped annular portion RA. As the polarizing lens 50, various structures having a lens action with respect to a specific polarization can be adopted.

[0072] In the above description, it was assumed that the HMD 200 is used while being worn on the head. However, the virtual image display devices 100A and 100B can also be used as a handheld display that peeks in like binoculars without being worn on the head. That is, in the present invention, the head-mounted display includes a handheld display.

[0073] In a specific embodiment, the virtual image display device includes, in order from the outside world, a light guide member that propagates illumination light from a light source, a ferroelectric liquid crystal panel that is provided on the light guide member and is in a scattered state with respect to the illumination light and a transparent state with respect to external light, a transmissive liquid crystal panel that is in a display state and a non-display state, a switching 1 / 2 wavelength plate that switches and passes the polarization direction of incident light in a first direction and a second direction that cross each other depending on the liquid crystal alignment direction, and a polarization lens that has a refractive power to form an image of the polarization in the first direction as a virtual image and passes the polarization in the second direction. When the transmissive liquid crystal panel is in the display state, the switching 1 / 2 wavelength plate makes the video light from the transmissive liquid crystal panel enter the polarization lens as polarization in the first direction. When the transmissive liquid crystal panel is in the non-display state, the external light that has passed through the transmissive liquid crystal panel enters the polarization lens as polarization in the second direction.

[0074] In the above virtual image display device, when the transmissive liquid crystal panel is in the display state, the switching 1 / 2 wavelength plate makes the video light from the transmissive liquid crystal panel enter the polarization lens as polarization in the first direction. When the transmissive liquid crystal panel is in the non-display state, the external light that has passed through the transmissive liquid crystal panel enters the polarization lens as polarization in the second direction. Therefore, it becomes possible to switch between the video light and the external light and observe them in parallel. That is, the transmissive liquid crystal panel can be used for video observation and external light observation by using the ferroelectric liquid crystal panel, and it is possible to suppress a decrease in the see-through transmittance while ensuring the brightness of the display.

[0075] In a virtual image display device according to a specific embodiment, a light source generates illumination light by switching among red, green, and blue. A transmissive liquid crystal panel has colorless pixels, modulates according to the color of the illumination light generated by the light source by means of the pixels, and sets the pixels in a transmissive state when the light source is not emitting light. In this case, in a sub-frame for video observation, there are display sections for each color that display red, green, and blue video light.

[0076] In a virtual image display device according to a specific embodiment, a light source generates illumination light by switching among red, green, and blue. A transmissive liquid crystal panel has colorless display pixels and colorless transmissive pixels, modulates by means of the colorless display pixels according to the color of the illumination light generated by the light source, and sets the colorless transmissive pixels in a transmissive state when the light source is not emitting light. In this case, in a sub-frame for video observation, there are display sections for each color that display red, green, and blue video light. In an external light observation sub-frame, by operating at least the colorless transmissive pixels, it becomes possible to observe a color video and a see-through image in a time-division manner.

[0077] In a virtual image display device according to a specific embodiment, an effective region of a ferroelectric liquid crystal panel is locally formed in a region facing the colorless display pixels of the transmissive liquid crystal panel. For the colorless transmissive pixels, there is no need to scatter external light, and by simply locally forming the effective region of the ferroelectric liquid crystal panel in the region facing the colorless display pixels, the illumination light can be selectively incident on the colorless display pixels.

[0078] In a virtual image display device according to a specific embodiment, a transmissive liquid crystal panel sets colorless display pixels in a transmissive state when the light source is not emitting light. In this case, in an external light observation sub-frame, the display pixels can be utilized, and the see-through image can be brightened.

[0079] In a virtual image display device according to a specific embodiment, a light source generates white illumination light. A transmissive liquid crystal panel has red, green, and blue sub-pixels, modulates by means of the sub-pixels of each color according to the light emission of the light source, and sets the sub-pixels of each color in a transmissive state when the light source is not emitting light. In this case, in a sub-frame for video observation, red, green, and blue video light can be displayed simultaneously.

[0080] In a virtual image display device in a specific embodiment, the light source generates white illumination light, the transmissive liquid crystal panel has red, green, blue, and colorless sub-pixels, modulation is performed by the sub-pixels of each color in accordance with the light emission of the light source, and the colorless sub-pixels are in a transmissive state when the light source is not emitting light. In this case, in the sub-frame for observing an image, red, green, and blue image light can be simultaneously displayed, and in the sub-frame for observing external light, by operating at least the colorless sub-pixels, it becomes possible to observe a color image and a see-through image in a time-division manner.

[0081] In a virtual image display device in a specific embodiment, the effective region of the ferroelectric liquid crystal panel is locally formed in a region facing the colorless sub-pixels of the transmissive liquid crystal panel. For the colorless sub-pixels, it is not necessary to scatter external light, and by locally forming the effective region of the ferroelectric liquid crystal panel in the region facing the sub-pixels of each color, the illumination light can be made to enter the sub-pixels of each color.

[0082] In a virtual image display device in a specific embodiment, the transmissive liquid crystal panel has the sub-pixels of each color in a transmissive state when the light source is not emitting light. In this case, in the sub-frame for observing external light, the sub-pixels of each color can be utilized, and the see-through image can be brightened.

[0083] In a virtual image display device in a specific embodiment, the ferroelectric liquid crystal panel emits the illumination light outside the light guide member in a scattered state and transmits external light in a transparent state.

[0084] In a virtual image display device in a specific embodiment, the colorless sub-pixels are arranged in a stripe shape or a Bayer shape together with the sub-pixels of each color to form pixels.

[0085] In a virtual image display device in a specific embodiment, the ferroelectric liquid crystal panel emits the illumination light outside the light guide member in a scattered state and transmits external light in a transparent state.

[0086] In the virtual image display device according to a specific embodiment, the ferroelectric liquid crystal panel is attached to one of a pair of planes of the light guide plate provided in the light guide member and fixed to the light guide plate.

[0087] In the virtual image display device according to a specific embodiment, the transmissive liquid crystal panel allows illumination light passing through the ferroelectric liquid crystal panel in the display state to enter and form video light, and transmits external light passing through the ferroelectric liquid crystal panel in the non-display state.

[0088] In the virtual image display device according to a specific embodiment, the transmissive liquid crystal panel includes a liquid crystal modulation member and a pair of polarizing plates sandwiching the liquid crystal modulation member. The pair of polarizing plates are set in a direction in which the polarization directions intersect or in a direction in which the polarization directions are parallel according to the characteristics and driving method of the liquid crystal modulation member.

[0089] In the virtual image display device according to a specific embodiment, it further includes a drive circuit that operates in harmony with the light source, the ferroelectric liquid crystal panel, the transmissive liquid crystal panel, and the switching 1 / 2 wavelength plate.

Explanation of Reference Numerals

[0090] AX…Optical axis, EY…Eye, IL, ILr, ILg, ILb…Illumination light, ML…Image light, OL…External light, PX…Pixel, PX(D)…Pixel for display, PX(T)…Pixel for transmission, PXs…Sub-pixel, QL…Image light, RA…Annular belt portion, SM1…R drive signal, SM2…G drive signal, SM3…B drive signal, SM4…W drive signal, SS1, SS2, SS3…Flashing signal, SW…On / off signal, US…Wearer, Z1, Z2…Sub-frame, 10…Light source, 10b…B light-emitting element, 10r…R light-emitting element, 10g…G light-emitting element, 11…Light guide plate, 12…Ferroelectric liquid crystal panel, 12a…Ferroelectric liquid crystal layer, 12b, 12c…Substrates, 14…Liquid crystal modulation member, 15…First polarizing plate, 16…Second polarizing plate, 17a…Liquid crystal layer, 17b, 17c…Substrates, 18a…Liquid crystal layer, 18b, 18c…Substrates, 20…Composite display member, 21…Light guide member, 22…Transmissive liquid crystal panel, 23…Switching 1 / 2 wavelength plate, 31…Liquid crystal layer, 32…Common electrode, 33…Pixel electrode, 35…Black matrix, 41r, 41g, 41b…Color filter, 50…Polarizing lens, 51…Effective area, 52…Transmission area, 80…Control device, 81…Drive circuit, 90…User terminal, 100A, 100B…Virtual image display device, 102…Drive device, 102a, 102b…Display drive unit, 103a, 103b…Display optical system, 104…Shade, 104a, 104b…Light transmission cover, 200…Head-mounted display device, 201…Binocular display device

Claims

1. In the order from the outside, a light guide member that propagates illumination light from a light source, a ferroelectric liquid crystal panel provided on the light guide member, which becomes a scattered state with respect to the illumination light and a transparent state with respect to external light, a transmissive liquid crystal panel that becomes a display state and a non-display state, a switching 1 / 2 wavelength plate that switches and passes the polarization directions of incident light to cross each other in a first direction and a second direction depending on the liquid crystal alignment direction, a polarization lens that has a refractive power to form an image of the polarization in the first direction as a virtual image and passes the polarization in the second direction, When the transmissive liquid crystal panel is in the display state, the switching 1 / 2 wavelength plate makes the video light from the transmissive liquid crystal panel incident on the polarization lens as the polarization in the first direction, and when the transmissive liquid crystal panel is in the non-display state, the external light passing through the transmissive liquid crystal panel is made incident on the polarization lens as the polarization in the second direction. A virtual image display device.

2. The light source generates illumination light by switching among red, green, and blue, The transmissive liquid crystal panel has colorless pixels, modulates according to the color of the illumination light generated by the light source by the pixels, and makes the pixels in a transmissive state when the light source is not emitting light. The virtual image display device according to Claim 1.

3. The light source generates illumination light by switching among red, green, and blue, The transmissive liquid crystal panel has colorless display pixels and colorless transmissive pixels, modulates by the colorless display pixels according to the color of the illumination light generated by the light source, and makes the colorless transmissive pixels in a transmissive state when the light source is not emitting light. The virtual image display device according to Claim 1.

4. The effective area of the ferroelectric liquid crystal panel is locally formed in a region facing the colorless display pixels of the transmissive liquid crystal panel. The virtual image display device according to Claim 3.

5. The transmissive liquid crystal panel makes the colorless display pixels in a transmissive state when the light source is not emitting light. The virtual image display device according to Claim 3.

6. The light source generates white illumination light, The transmissive liquid crystal panel has red, green, and blue sub-pixels, modulates by each color's sub-pixels according to the light emission of the light source, and makes each color's sub-pixels in a transmissive state when the light source is not emitting light. The virtual image display device according to Claim 1.

7. The light source generates white illumination light, The transmissive liquid crystal panel has red, green, blue, and colorless sub-pixels, modulates light according to the emission of the light source by the sub-pixels of each color, and makes the colorless sub-pixels in a transmissive state when the light source is not emitting light. The virtual image display device according to claim 1.

8. The effective area of the ferroelectric liquid crystal panel is locally formed in a region facing the colorless sub-pixels of the transmissive liquid crystal panel. The virtual image display device according to claim 7.

9. The transmissive liquid crystal panel makes the sub-pixels of each color in a transmissive state when the light source is not emitting light. The virtual image display device according to claim 7.

10. The colorless sub-pixels are arranged in a stripe shape or a Bayer shape together with the sub-pixels of each color to form pixels. The virtual image display device according to any one of claims 6 and 7.

11. The ferroelectric liquid crystal panel emits the illumination light outside the light guide member in the scattered state and transmits the external light in the transparent state. The virtual image display device according to claim 1.

12. The ferroelectric liquid crystal panel is attached to one of a pair of planes of a light guide plate provided in the light guide member and fixed to the light guide plate. The virtual image display device according to claim 1.

13. The transmissive liquid crystal panel makes the illumination light passing through the ferroelectric liquid crystal panel incident in the display state to form video light, and transmits the external light passing through the ferroelectric liquid crystal panel in the non-display state. The virtual image display device according to claim 1.

14. The transmissive liquid crystal panel has a liquid crystal modulation member and a pair of polarizing plates sandwiching the liquid crystal modulation member. The virtual image display device according to claim 1.

15. The virtual image display device further includes a drive circuit that operates by coordinating the light source, the ferroelectric liquid crystal panel, the transmissive liquid crystal panel, and the switching 1 / 2 wavelength plate. The virtual image display device according to claim 1.

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