Optical system, display device, and head-mounted device

Abstract

Provided are: an optical system which can be reduced in size, is low in manufacturing cost, and has a large positive refractive power; and a display device and a head-mounted device which are provided with the optical system. The optical system includes: a half mirror; at least one first optical element comprising a first film-like optical element affixed to the first plane; at least one second optical element including a second film-like optical element attached to a second plane, disposed at a position symmetrical to a position at which the at least one first optical element is disposed with respect to the half mirror, and having a shape symmetrical to a shape of the at least one first optical element with respect to the half mirror; and a convex lens.

Description

Technical Field

[0001] The present disclosure relates to an optical system, a display device, and a head-mounted device. Background Art

[0002] Patent document 1 discloses an optical element. In the optical element, a first linear polarized light passes through a first reflective linear polarizing plate, passes through a first phase difference plate and changes into right circular polarized light. A portion of the right circular polarized light is reflected by a partial reflector and changes into left circular polarized light. A portion of the right circular polarized light passes through the partial reflector.

[0003] The left circularly polarized light reflected by the partial reflector passes through the first phase difference plate and changes into the second linearly polarized light. The second linearly polarized light is reflected by the first reflective linear polarizing plate, passes through the first phase difference plate and changes into the left circularly polarized light. The left circularly polarized light passes through the partial reflector, passes through the second phase difference plate and changes into the second linearly polarized light. The second linearly polarized light passes through the second reflective linear polarizing plate.

[0004] The right circularly polarized light after passing through the partial reflector passes through the second phase difference plate and changes into the first linear polarized light. The first linear polarized light is reflected by the second reflective linear polarizing plate, passes through the second phase difference plate and changes into the right circularly polarized light. The right circularly polarized light is reflected by the partial reflector and changes into the left circularly polarized light. The left circularly polarized light passes through the second phase difference plate and changes into the second linear polarized light. The second linear polarized light passes through the second reflective linear polarizing plate.

[0005] As a result, the optical path length can be increased, and the optical element can be miniaturized (Paragraphs

[0016] and

[0026] -

[0036] )

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: International Publication No. 2021 / 200428 Summary of the invention

[0009] Problem that the invention aims to solve

[0010] A reflective linear polarizing plate is generally a film-shaped optical element and is attached to a lens surface.

[0011] In the optical element disclosed in Patent Document 1, when a reflective linear polarizing plate is attached to a convex lens surface, a bonding device capable of attaching a film-like optical element to the convex lens surface is required. Therefore, the cost required for the equipment to manufacture the optical element becomes high. In addition, in the optical element disclosed in Patent Document 1, when a reflective linear polarizing plate is attached to a convex lens surface, the following problems are prone to occur: bubbles are bitten between the reflective linear polarizing plate and the convex lens surface; wrinkles and looseness are generated in the reflective linear polarizing plate. Therefore, the yield of the optical element is reduced, and the cost required to manufacture the optical element is increased. On the other hand, in the optical element disclosed in Patent Document 1, when a reflective linear polarizing plate is attached to a flat lens surface, the positive optical power of the optical element is insufficient.

[0012] One aspect of the present disclosure is made in view of these problems. One aspect of the present disclosure aims to provide an optical system that can be miniaturized, has low manufacturing cost, has large positive power, and a display device and a head-mounted device including the optical system.

[0013] Solutions for solving problems

[0014] An optical system according to a first aspect of the present disclosure comprises: a half-reflecting mirror having a first surface and a second surface located on opposite sides to each other; a first at least one optical element comprising a first film-shaped optical element attached to a first plane, having a third surface and a fourth surface located on opposite sides to each other, the third surface being opposite to the first surface, and emitting a first circularly polarized light having a first rotational direction from the third surface when first linearly polarized light having a first polarization direction is incident on the fourth surface, and emitting a third circularly polarized light having a second rotational direction different from the first rotational direction from the third surface when second circularly polarized light having a second rotational direction different from the first rotational direction is incident on the third surface; and a second at least one optical element comprising a second film-shaped optical element attached to a second plane, having A fifth surface and a sixth surface are located on opposite sides to each other, the fifth surface is opposite to the second surface, when the fourth circularly polarized light having the first rotation direction is incident on the fifth surface, the fifth circularly polarized light having the first polarization direction is emitted from the fifth surface, and when the sixth circularly polarized light having the second rotation direction is incident on the fifth surface, the second linear polarized light having a second polarization direction perpendicular to the first polarization direction is emitted from the sixth surface, the second at least one optical element is arranged at a position symmetrical to the position where the first at least one optical element is arranged with respect to the half mirror, and has a shape symmetrical to the shape of the first at least one optical element with respect to the half mirror; and a convex lens, allowing the second linear polarized light to pass through.

[0015] A display device according to a second aspect of the present disclosure includes the optical system according to the first aspect of the present disclosure and a display that emits the first linearly polarized light.

[0016] A head mounted device according to a third aspect of the present disclosure includes the display device according to the second aspect of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 1 is a front view schematically showing the headgear according to the first embodiment and the head of a person wearing the headgear.

[0018] Figure 2 It is a cross-sectional view schematically showing the display device included in the head mounted device according to the first embodiment.

[0019] Figure 3 1 is a diagram showing changes in the polarization state of the display device included in the head mounted device according to the first embodiment.

[0020] Figure 4 The diagram shows the relationship between a first transmission axis and a first reflection axis of a first reflective polarizing plate included in the head-mounted device according to the first embodiment, and a second transmission axis and a second reflection axis of a second reflective polarizing plate included in the head-mounted device.

[0021] Figure 5 The diagram shows the relationship between the first fast axis and the first slow axis of the first quarter wavelength plate included in the head-mounted device according to the first embodiment, and the second fast axis and the second slow axis of the second quarter wavelength plate included in the head-mounted device.

[0022] Figure 6 It is a cross-sectional view schematically showing a display device included in the head mounted device according to the second embodiment.

[0023] Figure 7 1 is a cross-sectional view schematically showing a display device included in the head mounted device according to the third embodiment.

[0024] Figure 8 The diagram shows the relationship between the first rotation direction of the first cholesteric liquid crystal film of the head-mounted device of the third embodiment and the second rotation direction of the second cholesteric liquid crystal film of the head-mounted device, and the relationship between the first rotation direction of the first polarizer hologram (PVH) film of the head-mounted device of the fourth embodiment and the second rotation direction of the second PVH film of the head-mounted device.

[0025] Fig. 9 1 is a cross-sectional view schematically showing a display device included in a head mounted device according to a fourth embodiment.

[0026] Fig.101 is a cross-sectional view schematically showing a display device included in a head mounted device according to a fifth embodiment.

[0027] Fig.11 1 is a cross-sectional view schematically showing a display device included in a head mounted device according to a sixth embodiment.

[0028] Fig.12 1 is a cross-sectional view schematically showing a display device included in a head mounted device according to a seventh embodiment.

[0029] Fig.13 FIG. 1 is a cross-sectional view schematically showing a display device included in a head mounted device according to an eighth embodiment.

[0030] Fig.14 1 is a cross-sectional view schematically showing a display device included in a head mounted device according to a ninth embodiment.

[0031] Fig.15 is a cross-sectional view schematically illustrating a display device according to a first reference example.

[0032] Fig.16 It is a diagram showing changes in the polarization state of the display device of the first reference example.

[0033] Fig.17 is a cross-sectional view schematically illustrating a display device according to a second reference example.

[0034] Fig.18 It is a diagram showing changes in the polarization state of the display device of the second reference example.

[0035] Description of Reference Numerals

[0036] 1 head-mounted device; 11 housing; 12 display device; 101 display; 101a display surface; 102 optical system; 111 transparent plate; 111a one main surface; 111b another main surface; 112 half-reflecting mirror; 112a first surface; 112b second surface; 113 first at least one optical element; 1133 third surface; 1134 fourth surface; 114 second at least one optical element; 1145 fifth surface; 1146 sixth surface; 115 polarizing plate; 116 convex lens; 116a flat lens surface; 116b convex lens surface; 117 transparent plate; 117a: main surface; 12 1: first reflective polarizing plate; 121a: first principal surface; 121b: second principal surface; 121c: first transmission axis; 121d: first reflection axis; 122: first quarter wavelength plate; 122a: first surface; 122b: second surface; 122e: first phase-advancing axis; 122f: first phase-delaying axis; 123: first lens; 123a: first convex lens surface; 123b: first flat lens surface; 124: first cholesteric liquid crystal film; 124a: first principal surface; 124b: second principal surface; 124h: first rotation direction; 125: first polarizer holographic (PVH) film; 125a: first principal surface; 125b: second principal surface second principal surface; 125h first rotation direction; 131 second reflective polarizing plate; 131a first principal surface; 131b second principal surface; 131c second transmission axis; 131d second reflection axis; 132 second 1 / 4 wavelength plate; 132a first surface; 132b second surface; 132e second phase advance axis; 132f second phase lag axis; 133 second lens; 133a second convex lens surface; 133b second flat lens surface; 134 second cholesteric liquid crystal film; 134a first principal surface; 134b second principal surface; 134h second rotation direction; 135 second PVH film; 135a first principal surface; 134b second principal surface; 134h second rotation direction; 135 second PVH film; 135a second a main surface; 135b a second main surface; 135h a second direction of rotation; 181 linear polarization; 182 linear polarization; 183 circular polarization; 184p circular polarization; 185p linear polarization; 186p linear polarization; 187p circular polarization; 188p circular polarization; 189p linear polarization; 190p linear polarization; 184q circular polarization; 185q linear polarization; 186q linear polarization; 187q circular polarization; 188q circular polarization; 189q linear polarization; 190p linear polarization; 82 display device; 801 display; 802 1 / 4 wavelength plate; 803 half-reflecting mirror; 804 1 / 4 wavelength plate; 805 reflective polarizing plate; 811 lens; 812 lens; 881 linear polarized light; 882 circular polarized light; 883 circular polarized light; 884 linear polarized light; 885 linear polarized light; 886 circular polarized light; 887 circular polarized light; 888 linear polarized light; 889 linear polarized light; 92 display device; 901 display; 902 reflective polarizing plate; 903 1 / 4 wavelength plate; 904 half-reflecting mirror; 905 1 / 4 wavelength plate; 906 reflective polarizing plate; 911 lens;912 lens; 913 glass plate; 981 linear polarized light; 982 linear polarized light; 983 circular polarized light; 984p circular polarized light; 985p linear polarized light; 986p linear polarized light; 987p circular polarized light; 988p circular polarized light; 989p linear polarized light; 990p linear polarized light; 989q circular polarized light; 985q linear polarized light; 986q linear polarized light; 987p circular polarized light; 988p circular polarized light; 989p linear polarized light; 990p linear polarized light; H head; E eye; D1 first polarization direction; D2 second polarization direction; DR first rotation direction; DL second rotation direction. ; DETAILED DESCRIPTION

[0037] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. In addition, regarding the drawings, the same or equivalent elements are denoted by the same reference numerals, and repeated descriptions are omitted.

[0038] 1 First Reference Example

[0039] Hereinafter, in order to help understand the display device included in the head mounted device (head mounted device) of the first embodiment, a display device according to a first reference example will be described.

[0040] Fig.15 is a cross-sectional view schematically illustrating a display device according to a first reference example. Fig.16 It is a diagram showing changes in the polarization state of the display device of the first reference example.

[0041] Fig.15 and Fig.16 The display device 82 of the first reference example shown in the figure includes a thin pancake lens (PancakeLens). In this pancake lens, a single path method is adopted to guide light to the eye E through one optical path.

[0042] like Fig.15 and Fig.16 As shown in the figure, the display device 82 includes a display 801 , a quarter wavelength plate 802 , a half mirror 803 , a quarter wavelength plate 804 , and a reflective polarizing plate 805 .

[0043] The display 801, the quarter wavelength plate 802, the half mirror 803, the quarter wavelength plate 804, and the reflective polarizing plate 805 are arranged in a row in the order described.

[0044] The display 801 emits linearly polarized light 881 having a first polarization direction D1.

[0045] The quarter-wave plate 802 transmits the linearly polarized light 881 and emits the circularly polarized light 882 having the first rotation direction DR.

[0046] The half mirror 803 transmits a part of the circularly polarized light 882 and emits circularly polarized light 883 having a first rotation direction DR.

[0047] The quarter-wave plate 804 transmits the circularly polarized light 883 and emits the linearly polarized light 884 having the first polarization direction D1.

[0048] The reflective polarizing plate 805 reflects the linearly polarized light 884 and emits the linearly polarized light 885 having the first polarization direction D1.

[0049] The quarter-wave plate 804 transmits the linearly polarized light 885 and emits circularly polarized light 886 having a first rotation direction DR.

[0050] The half mirror 803 reflects a part of the circularly polarized light 886 and emits circularly polarized light 887 having the second rotation direction DL.

[0051] The quarter-wave plate 804 transmits the circularly polarized light 887 and emits the linearly polarized light 888 having the second polarization direction D2.

[0052] The reflective polarizing plate 805 transmits the linearly polarized light 888 and emits the linearly polarized light 889 having the second polarization direction D2.

[0053] Linearly polarized light 889 reaches eye E.

[0054] In the display device 82, light travels back and forth between the half mirror 803 and the reflective polarizing plate 805. This can lengthen the optical path of the light. Thus, the optical system including the 1 / 4 wavelength plate 802, the half mirror 803, the 1 / 4 wavelength plate 804, and the reflective polarizing plate 805 becomes a thin pancake lens.

[0055] In the display device 82, the half mirror 803 reflects part of the circularly polarized light 882, thereby losing about 50% of the light. In addition, the half mirror 803 transmits part of the circularly polarized light 886, thereby losing about 25% of the light. Therefore, about 75% of the light is lost as a whole.

[0056] like Fig.15 As shown, the display device 82 includes lenses 811 and 812. A quarter wavelength plate 802 is attached to the display surface of the display 801. A half mirror 803 is attached to the convex lens surface of the lens 811. A quarter wavelength plate 804 and a reflective polarizing plate 805 are attached to the flat lens surface of the lens 812.

[0057] 2 Second reference example

[0058] Hereinafter, in order to help understand the display device included in the head mounted device of the first embodiment, a display device according to a second reference example will be described.

[0059] Fig.17 is a cross-sectional view schematically illustrating a display device according to a second reference example. Fig.18 It is a diagram showing changes in the polarization state of the display device of the second reference example.

[0060] Fig.17 and 18 The display device 92 of the second reference example shown in the figure includes a thin pancake lens. In this pancake lens, a dual-path method is adopted in which light is guided to the eye E via two different optical paths.

[0061] like Fig.17 and 18 As shown in the figure, the display device 92 includes a display 901 , a reflective polarizing plate 902 , a quarter-wave plate 903 , a half mirror 904 , a quarter-wave plate 905 , and a reflective polarizing plate 906 .

[0062] The display 901, the reflective polarizing plate 902, the quarter-wave plate 903, the half mirror 904, the quarter-wave plate 905, and the reflective polarizing plate 906 are arranged in a row in the order described.

[0063] The display 901 emits linearly polarized light 981 having a first polarization direction D1.

[0064] The reflective polarizing plate 902 transmits the linearly polarized light 981 and emits the linearly polarized light 982 having the first polarization direction D1 .

[0065] The quarter-wave plate 903 transmits the linearly polarized light 982 and emits circularly polarized light 983 having the first rotation direction DR.

[0066] The half mirror 904 reflects a part of the circularly polarized light 983 to emit circularly polarized light 984p having the second rotation direction DL. Also, the half mirror 904 transmits a part of the circularly polarized light 983 to emit circularly polarized light 984q having the first rotation direction DR.

[0067] The quarter-wave plate 903 transmits the circularly polarized light 984 p and emits the linearly polarized light 985 p having the second polarization direction D2 .

[0068] The reflective polarizing plate 902 reflects the linearly polarized light 985p and emits the linearly polarized light 986p having the second polarization direction D2.

[0069] The quarter-wave plate 903 transmits the linearly polarized light 986 p and emits circularly polarized light 987 p having the second rotation direction DL.

[0070] The half mirror 904 transmits a part of the circularly polarized light 987p and emits circularly polarized light 988p having the second rotation direction DL.

[0071] The quarter-wave plate 905 transmits the circularly polarized light 988p and emits linearly polarized light 989p having the second polarization direction D2.

[0072] The reflective polarizing plate 906 transmits the linearly polarized light 989 p and emits the linearly polarized light 990 p having the second polarization direction D2 .

[0073] The quarter-wave plate 905 transmits the circularly polarized light 984q and emits linearly polarized light 985q having the first polarization direction D1.

[0074] The reflective polarizing plate 906 reflects the linearly polarized light 985q and emits the linearly polarized light 986q having the first polarization direction D1.

[0075] The quarter-wave plate 905 transmits the linearly polarized light 986q and emits circularly polarized light 987q having the first rotation direction DR.

[0076] The half mirror 904 reflects a part of the circularly polarized light 987q and emits circularly polarized light 988q having the second rotation direction DL.

[0077] The quarter-wave plate 905 transmits the circularly polarized light 988q and emits linearly polarized light 989q having the second polarization direction D2.

[0078] The reflective polarizing plate 906 transmits the linearly polarized light 989q and emits the linearly polarized light 990q having the second polarization direction D2.

[0079] The linearly polarized light 890p and 890q reaches the eye E.

[0080] The reflective polarizing plate 902, the quarter wavelength plate 903, the half mirror 904, the quarter wavelength plate 905, and the reflective polarizing plate 906 are designed to be symmetrical with respect to the half mirror 904. This can prevent the image formed at the eye E from becoming a double image.

[0081] In the display device 92, part of the light travels back and forth between the half mirror 904 and the reflective polarizing plate 902. In addition, part of the light travels back and forth between the half mirror 904 and the reflective polarizing plate 906. Thus, the optical path of the light can be extended. Thus, the optical system including the reflective polarizing plate 902, the quarter wavelength plate 903, the half mirror 904, the quarter wavelength plate 905, and the reflective polarizing plate 906 becomes a thin pancake lens.

[0082] In the display device 92, the half mirror 904 reflects a part of the circularly polarized light 987q, thereby losing about 25% of the light amount. In addition, the reflective polarizing plate 902 transmits a part of the linearly polarized light 985p, thereby losing about 25% of the light amount. Therefore, about 50% of the light amount is lost as a whole. Therefore, the amount of light lost in the display device 92 is less than the amount of light lost in the display device 82.

[0083] like Fig.17 As shown in the figure, the display device 92 includes a lens 911, a lens 912, and a glass plate 913. The reflective polarizing plate 902 is attached to the convex lens surface of the lens 911. The 1 / 4 wavelength plate 903, the half mirror 904, and the 1 / 4 wavelength plate 905 are attached to the main surface of the glass plate 913. The reflective polarizing plate 906 is attached to the convex lens surface of the lens 912. The 1 / 4 wavelength plate 903 only needs to be arranged between the half mirror 904 and the reflective polarizing plate 902. Therefore, the 1 / 4 wavelength plate 903 can also be attached to the convex lens surface of the lens 911. The 1 / 4 wavelength plate 905 only needs to be arranged between the half mirror 904 and the reflective polarizing plate 906. Therefore, the 1 / 4 wavelength plate 905 can also be attached to the convex lens surface of the lens 912.

[0084] In display device 92, reflective polarizing plates 902 and 906 are attached to the convex lens surfaces of lenses 911 and 912, respectively. Therefore, an attaching device capable of attaching a film-like optical element to the convex lens surface is required. Therefore, the cost required for the equipment to manufacture display device 92 becomes high. In addition, the following problems arise: bubbles are bitten between reflective polarizing plate 902 and lens 911; bubbles are bitten between reflective polarizing plate 906 and lens 912; wrinkles and sags are generated in reflective polarizing plate 902; wrinkles and sags are generated in reflective polarizing plate 906. Therefore, the yield rate of display device 92 becomes low, and the cost required to manufacture display device 92 becomes high.

[0085] 3. First Implementation

[0086] 3.1 Headset

[0087] Figure 1 1 is a front view schematically showing the headgear according to the first embodiment and the head of a person wearing the headgear.

[0088] Figure 1 The head mounted device 1 shown in the figure is worn on a person's head H. The head mounted device 1 is a goggle type head mounted device. The head mounted device 1 may be a head mounted device other than the goggle type head mounted device. For example, the head mounted device 1 may be a headset type, a glasses type, or the like.

[0089] The head mounted device 1 displays images of virtual reality (VR). The head mounted device 1 may also display images other than VR images. For example, the head mounted device 1 may also display images of augmented reality (AR), mixed reality (MR), and the like.

[0090] like Figure 1 As shown in the figure, the head mounted device 1 includes a housing 11 and a display device 12 .

[0091] The housing 11 is attachable to and detachable from the head H. The housing 11 accommodates a display device 12 .

[0092] The display device 12 faces the eyes located in the head H. The display device 12 displays an image toward the eyes facing the head H.

[0093] 3.2 Display Device

[0094] Figure 2 It is a cross-sectional view schematically showing the display device included in the head mounted device according to the first embodiment. Figure 3 1 is a diagram showing changes in the polarization state of the display device included in the head mounted device according to the first embodiment.

[0095] Figure 2 and Figure 3 The display device 12 shown in the figure includes a thin pancake lens. The pancake lens adopts a dual-path method of guiding light to the eye E via two optical paths.

[0096] like Figure 2 As shown in the figure, the display device 12 includes a display 101 and an optical system 102 .

[0097] The display 101 emits a first linear polarized light (linear polarized light 181). The display 101 emits a first linear polarized light (linear polarized light 181) having a distribution of brightness and chromaticity corresponding to an input image signal. Thus, the display 101 displays an image corresponding to the input image signal. The display 101 has a display surface 101a. The display 101 displays an image on the display surface 101a. The display 101 is a liquid crystal display (LCD), a self-luminous display, or the like.

[0098] The optical system 102 focuses the light emitted from the display 101 onto the eye E. Thus, the optical system 102 forms an image on the eye E corresponding to the video displayed on the display 101 .

[0099] 3.3 Optical system

[0100] like Figure 2 and Figure 3As shown in the figure, the optical system 102 includes a transparent plate 111 , a half mirror 112 , at least one first optical element 113 , at least one second optical element 114 , a polarizing plate 115 , and a convex lens 116 .

[0101] The transparent plate 111 is disposed between the first at least one optical element 113 and the second at least one optical element 114. The transparent plate 111 is disposed between the first convex lens surface 123a of the first lens 123 of the first at least one optical element 113 and the second convex lens surface 133a of the second lens 133 of the second at least one optical element 114.

[0102] The transparent plate 111 has one main surface 111a and the other main surface 111b. The one main surface 111a and the other main surface 111b are located on opposite sides to each other.

[0103] The transparent plate 111 is a glass plate or the like.

[0104] The half mirror 112 is disposed on the other principal surface 111b of the transparent plate 111. The half mirror 112 may be disposed on one principal surface 111a of the transparent plate 111.

[0105] The half mirror 112 has a first surface 112a and a second surface 112b. The first surface 112a and the second surface 112b are located on opposite sides to each other.

[0106] The first at least one optical element 113 has a third surface 1133 and a fourth surface 1134. The third surface 1133 is opposite to the first surface 112a of the half mirror 112. The fourth surface 1134 is opposite to the display surface 101a of the display 101.

[0107] When the first linear polarized light (linear polarized light 181) having the first polarization direction D1 is incident on the fourth surface 1134, the first at least one optical element 113 transmits the incident first linear polarized light (linear polarized light 181) and emits the first circularly polarized light (circularly polarized light 183) having the first rotation direction DR from the third surface 1133. When the second circularly polarized light (circularly polarized light 184p) having the second rotation direction DL different from the first rotation direction DR is incident on the third surface 1133, the first at least one optical element 113 reflects the incident second circularly polarized light (circularly polarized light 184p) and emits the third circularly polarized light (circularly polarized light 187p) having the second rotation direction DL from the third surface 1133.

[0108] The second at least one optical element 114 has a fifth surface 1145 and a sixth surface 1146. The fifth surface 1145 is opposite to the second surface 112b of the half mirror 112. The sixth surface 1146 is opposite to the third flat lens surface 116a of the convex lens 116.

[0109] When the fourth circularly polarized light (circularly polarized light 184q) having the first rotation direction DR is incident on the fifth surface 1145, the second at least one optical element 114 reflects the incident fourth circularly polarized light (circularly polarized light 184q) and emits the fifth circularly polarized light (circularly polarized light 187q) having the first rotation direction DR from the fifth surface 1145. When the sixth circularly polarized light (circularly polarized lights 188p and 188q) having the second rotation direction DL is incident on the fifth surface 1145, the second at least one optical element 114 transmits the incident sixth circularly polarized light (circularly polarized lights 188p and 188q) and emits the second linearly polarized light (linearly polarized lights 190p and 190q) having the second polarization direction D2 perpendicular to the first polarization direction D1 from the sixth surface 1146.

[0110] Thus, the first at least one optical element 113 transmits the linearly polarized light 181 having the first polarization direction D1 and emits the circularly polarized light 183 having the first rotation direction DR.

[0111] The half mirror 112 reflects a part of the circularly polarized light 183 and emits a circularly polarized light 184p having the second rotation direction DL. Also, the half mirror 112 transmits a part of the circularly polarized light 183 and emits a circularly polarized light 184q having the first rotation direction DR.

[0112] The at least one first optical element 113 reflects the circularly polarized light 184p and emits circularly polarized light 187p having the second rotation direction DL.

[0113] The half mirror 112 transmits a part of the circularly polarized light 187p and emits circularly polarized light 188p having the second rotation direction DL.

[0114] The second at least one optical element 114 transmits the circularly polarized light 188p and emits a linearly polarized light 190p having a second polarization direction D2.

[0115] The at least one second optical element 114 reflects the circularly polarized light 184q and emits circularly polarized light 187q having the first rotation direction DR.

[0116] The half mirror 112 reflects a part of the circularly polarized light 187q and emits circularly polarized light 188q having the second rotation direction DL.

[0117] The at least one second optical element 114 transmits the circularly polarized light 188q and emits a linearly polarized light 190q having a second polarization direction D2.

[0118] The second at least one optical element 114 is arranged at a position symmetrical to the position where the first at least one optical element 113 is arranged with respect to the half mirror 112. The second at least one optical element 114 has a shape symmetrical to the shape of the first at least one optical element 113 with respect to the half mirror 112. Symmetrical with respect to the half mirror 112 means being optically symmetrical, which means that the optical characteristics affecting the optical path of the light, such as the distribution of the refractive index, are symmetrical. Thus, the optical paths of the linearly polarized lights 190p and 190q can be made consistent with each other. Thus, the image formed by the first at least one optical element 113, the half mirror 112, and the second at least one optical element 114 can be suppressed from becoming a double image.

[0119] The polarizing plate 115 is arranged on the eye E side relative to the second at least one optical element 114. Thus, the polarizing plate 115 transmits the linearly polarized light 190p and 190q. The polarizing plate 115 suppresses the reflected light generated by the linearly polarized light 190p and 190q reflected by the user's eye E, face, etc., from being reflected by the second reflective polarizing plate 131 included in the second at least one optical element 114 and reaching the user's eye E. Thus, the polarizing plate 115 improves the quality of the image displayed by the display device 12. The polarizing plate 115 may also be omitted.

[0120] The convex lens 116 is arranged on the eye E side relative to the polarizing plate 115 and the second at least one optical element 114. Thus, the convex lens 116 transmits the second linearly polarized light (linearly polarized light 190p and 190q) after passing through the polarizing plate 115. The second linearly polarized light (linearly polarized light 190p and 190q) after passing through the convex lens 116 is guided to the eye E.

[0121] The convex lens 116 is disposed outside the first at least one optical element 113, the half mirror 112, and the second at least one optical element 114, which must have symmetry. This can increase the positive power of the optical system 102 and expand the field of view (FOV) of the optical system 102.

[0122] Convex lens 116 is disposed outside a region between first reflective polarizing plate 121 included in first at least one optical element 113 and second reflective polarizing plate 131 included in second at least one optical element 114 for polarization compensation. Therefore, convex lens 116 may be a lens made of a material having residual birefringence.

[0123] 3.4 First at least one optical element

[0124] Figure 4The diagram shows the relationship between a first transmission axis and a first reflection axis of a first reflective polarizing plate included in the head-mounted device according to the first embodiment, and a second transmission axis and a second reflection axis of a second reflective polarizing plate included in the head-mounted device. Figure 5 The diagram shows the relationship between the first fast axis and the first slow axis of the first quarter wavelength plate included in the head-mounted device according to the first embodiment, and the second fast axis and the second slow axis of the second quarter wavelength plate included in the head-mounted device.

[0125] like Figure 2 and Figure 3 As shown, the first at least one optical element 113 includes a first reflective polarizing plate 121 , a first quarter-wave plate 122 , and a first lens 123 .

[0126] The first reflective polarizing plate 121 is a first film-shaped optical element. The first reflective polarizing plate 121 has a first main surface 121a and a second main surface 121b. The first main surface 121a and the second main surface 121b are located on opposite sides. The second main surface 121b becomes the fourth surface 1134 of the first at least one optical element 113.

[0127] like Figure 4 As shown, the first reflective polarizing plate 121 has a first transmission axis 121c and a first reflection axis 121d. The first transmission axis 121c and the first reflection axis 121d are perpendicular to each other. The first polarization direction D1 is parallel to the first transmission axis 121c. The second polarization direction D2 is parallel to the first reflection axis 121d. Thus, the first reflective polarizing plate 121 selectively transmits the linear polarized light 181 having the first polarization direction D1 and emits the linear polarized light 182 having the first polarization direction D1. In addition, the first reflective polarizing plate 121 selectively reflects the linear polarized light 185p having the second polarization direction D2 and emits the linear polarized light 186p having the second polarization direction D2.

[0128] The first quarter-wave plate 122 is disposed between the half mirror 112 and the first reflective polarizing plate 121 .

[0129] The first quarter wavelength plate 122 has a first surface 122a and a second surface 122b. The first surface 122a and the second surface 122b are located on opposite sides to each other. The first surface 122a becomes the third surface 1133 of the first at least one optical element 113.

[0130] like Figure 5As shown, the first 1 / 4 wavelength plate 122 has a first fast axis 122e and a first slow axis 122f. The first fast axis 122e and the first slow axis 122f are perpendicular to each other. The first polarization direction D1 is 45° to the first fast axis 122e. The second polarization direction D2 is 45° to the first fast axis 122e. Thus, the first 1 / 4 wavelength plate 122 transmits the linear polarized light 182 having the first polarization direction D1 and emits the circular polarized light 183 having the first rotation direction DR. In addition, the first 1 / 4 wavelength plate 122 transmits the circular polarized light 184p having the second rotation direction DL and emits the linear polarized light 185p having the second polarization direction D2. In addition, the first 1 / 4 wavelength plate 122 transmits the linear polarized light 186p having the second polarization direction D2 and emits the circular polarized light 187p having the second rotation direction DL.

[0131] Thus, when the linearly polarized light 181 having the first polarization direction D1 is incident on the fourth surface 1134, the first at least one optical element 113 transmits the incident linearly polarized light 181 and emits circularly polarized light 183 having the first rotation direction DR from the third surface 1133. In addition, when the circularly polarized light 184p having the second rotation direction DL is incident on the third surface 1133, the first at least one optical element 113 reflects the incident circularly polarized light 184p and emits circularly polarized light 187p having the second rotation direction DL from the third surface 1133.

[0132] The first lens 123 is a first plano-convex lens. Therefore, the first lens 123 has positive power. The first lens 123 has a first convex lens surface 123a and a first plano lens surface 123b. The first convex lens surface 123a and the first plano lens surface 123b are located on opposite sides of each other. The first convex lens surface 123a is opposite to the first surface 112a of the semi-reflecting mirror 112. The first convex lens surface 123a can be any one of a spherical surface, an aspherical surface, and a free-form surface.

[0133] The first reflective polarizing plate 121 and the first quarter wavelength plate 122 are attached to the first flat lens surface 123b of the first lens 123 as the first plane. Thus, the first reflective polarizing plate 121 and the first quarter wavelength plate 122 have a flat shape.

[0134] Since the first reflective polarizing plate 121 is attached to the first flat lens surface 123b of the first lens 123, there is no need for an attaching device that can attach a film-shaped optical element to a convex lens surface. Therefore, the cost required for the equipment to manufacture the optical system 102 is reduced. In addition, since the first reflective polarizing plate 121 is attached to the first flat lens surface 123b, the following problems are not likely to occur: bubbles are bitten between the first reflective polarizing plate 121 and the first lens 123; wrinkles and looseness are generated in the first reflective polarizing plate 121. Therefore, the yield rate of the optical system 102 is increased, and the cost required to manufacture the optical system 102 is reduced.

[0135] Since both the first reflective polarizing plate 121 and the first quarter wavelength plate 122 are attached to the first lens 123, the first reflective polarizing plate 121 and the first quarter wavelength plate 122 can be attached to the first lens 123 simply by attaching the laminate of the first reflective polarizing plate 121 and the first quarter wavelength plate 122 to the first lens 123. The laminate can be easily manufactured. Thus, the cost required to attach the first reflective polarizing plate 121 and the first quarter wavelength plate 122 to the first lens 123 can be reduced.

[0136] Since the first lens 123 is a plano-convex lens, the cost of a mold required for manufacturing the first lens 123 can be reduced compared to a case where the first lens 123 is a biconvex lens.

[0137] 3.5 Second at least one optical element

[0138] like Figure 2 and Figure 3 As shown, the second at least one optical element 114 includes a second reflective polarizing plate 131 , a second quarter-wave plate 132 , and a second lens 133 .

[0139] The second reflective polarizing plate 131 is a second film-shaped optical element. The second reflective polarizing plate 131 has a first main surface 131a and a second main surface 131b. The first main surface 131a and the second main surface 131b are located on opposite sides. The second main surface 131b becomes the sixth surface 1146 of the second at least one optical element 114.

[0140] like Figure 4As shown, the second reflective polarizing plate 131 has a second transmission axis 131c and a second reflection axis 131d. The second transmission axis 131c and the second reflection axis 131d are perpendicular to each other. The first polarization direction D1 is parallel to the second reflection axis 131d. The second polarization direction D2 is parallel to the second transmission axis 131c. As a result, the second reflective polarizing plate 131 selectively reflects the linear polarized light 185q having the first polarization direction D1 and emits the linear polarized light 186q having the first polarization direction D1. In addition, the second reflective polarizing plate 131 selectively transmits the linear polarized lights 189p and 189q having the second polarization direction D2 and emits the linear polarized lights 190p and 190q having the second polarization direction D2.

[0141] The second transmission axis 131c of the second reflective polarizing plate 131 is perpendicular to the first transmission axis 121c of the first reflective polarizing plate 121. The second reflection axis 131d of the second reflective polarizing plate 131 is perpendicular to the first reflection axis 121d of the first reflective polarizing plate 121.

[0142] The second quarter-wave plate 132 is disposed between the half mirror 112 and the second reflective polarizing plate 131 .

[0143] The second quarter wavelength plate 132 has a first surface 132a and a second surface 132b. The first surface 132a and the second surface 132b are located on opposite sides to each other. The first surface 132a becomes the fifth surface 1145 of the second at least one optical element 114.

[0144] like Figure 5 As shown, the second quarter wavelength plate 132 has a second fast axis 132e and a second slow axis 132f. The second fast axis 132e and the second slow axis 132f are perpendicular to each other. The first polarization direction D1 is 45° to the second fast axis 132e. The second polarization direction D2 is 45° to the second fast axis 132e. The second fast axis 132e is perpendicular to the first fast axis 122e of the first quarter wavelength plate 122. The second slow axis 132f is perpendicular to the first slow axis 122f of the first quarter wavelength plate 122. Thus, the second quarter wavelength plate 132 transmits the circularly polarized light 184q having the first rotation direction DR and emits the linearly polarized light 185q having the first polarization direction D1. In addition, the second quarter wavelength plate 132 transmits the linearly polarized light 186q having the first polarization direction D1 and emits the circularly polarized light 187q having the first rotation direction DR. In addition, the second quarter-wave plate 132 transmits the circularly polarized lights 188 p and 188 q having the second rotation direction DL, and emits the linearly polarized lights 189 p and 189 q having the second polarization direction D2.

[0145] Thus, when circularly polarized light 184q having the first rotation direction DR is incident on the fifth surface 1145, the at least one second optical element 114 reflects the incident circularly polarized light 184q, and emits circularly polarized light 187q having the first rotation direction DR from the fifth surface 1145. In addition, when circularly polarized light 188p and 188q having the second rotation direction DL is incident on the fifth surface 1145, the at least one second optical element 114 transmits the incident circularly polarized light 188p and 188q, and emits linearly polarized light 190p and 190q having the second polarization direction D2 from the sixth surface 1146.

[0146] The second lens 133 is a second plano-convex lens. Therefore, the second lens 133 has positive power. The second lens 133 has a second convex lens surface 133a and a second plano lens surface 133b. The second convex lens surface 133a and the second plano lens surface 133b are located on opposite sides of each other. The second convex lens surface 133a is opposite to the second surface 112b of the semi-reflecting mirror 112. The second convex lens surface 133a can be any one of a spherical surface, an aspherical surface, and a free-form surface.

[0147] The second reflective polarizing plate 131 and the second quarter wavelength plate 132 are attached to the second flat lens surface 133b of the second lens 133 as the second plane. Thus, the second reflective polarizing plate 131 and the second quarter wavelength plate 132 have a flat shape.

[0148] Since the second reflective polarizing plate 131 is attached to the second flat lens surface 133b of the second lens 133, there is no need for an attaching device that can attach a film-shaped optical element to a convex lens surface. Therefore, the cost required for the equipment to manufacture the optical system 102 is reduced. In addition, since the second reflective polarizing plate 131 is attached to the second flat lens surface 133b, the following problems are not likely to occur: bubbles are bitten between the second reflective polarizing plate 131 and the second lens 133; wrinkles and looseness are generated in the second reflective polarizing plate 131. Therefore, the yield rate of the optical system 102 is increased, and the cost required to manufacture the optical system 102 is reduced.

[0149] Since both the second reflective polarizing plate 131 and the second quarter wavelength plate 132 are attached to the second lens 133, the second reflective polarizing plate 131 and the second quarter wavelength plate 132 can be attached to the second lens 133 simply by attaching the laminate of the second reflective polarizing plate 131 and the second quarter wavelength plate 132 to the second lens 133. The laminate can be easily manufactured. Thus, the cost required to attach the second reflective polarizing plate 131 and the second quarter wavelength plate 132 to the second lens 133 can be reduced.

[0150] The second lens 133 is arranged at a position symmetrical to the position where the first lens 123 is arranged with respect to the half mirror 112. The second lens 133 has a shape symmetrical to the shape of the first lens 123 with respect to the half mirror 112. This can prevent the image formed by the optical system 102 from becoming a double image.

[0151] 3.6 Thinning of optical systems and miniaturization of display devices and head-mounted devices

[0152] In the display device 12, part of the light emitted by the display 101 travels back and forth between the half mirror 112 and the first reflective polarizing plate 121. In addition, part of the light emitted by the display 101 travels back and forth between the half mirror 112 and the second reflective polarizing plate 131. Therefore, the optical system 102 is a folding optical system. As a result, the optical path of the light can be extended. As a result, the optical system 102 can be made into a thin pancake lens. As a result, the display device 12 and the head mounted device 1 having the optical system 102 can be miniaturized.

[0153] In recent years, virtual space called metaverse has attracted attention. Therefore, as a tool for accessing the world built in this virtual space, the popularity of head-mounted devices that provide VR images is expected. One reason that hinders the popularity of head-mounted devices that provide VR content is that the housing of the head-mounted devices is large. Therefore, the head-mounted device 1 that can be miniaturized can eliminate this one reason.

[0154] 3.7 Optical Power and FOV of Optical Systems

[0155] The first lens 123 and the second lens 133 are plano-convex lenses so that the first reflective polarizing plate 121 and the second reflective polarizing plate 131 can be attached to a plane.

[0156] When the first lens 123 and the second lens 133 are plano-convex lenses, the positive refractive power of the first lens 123 and the second lens 133 becomes smaller than when the first lens 123 and the second lens 133 are biconvex lenses, and the positive refractive power of the optical system 102 becomes smaller.

[0157] The convex lens 116 increases the positive power of the optical system 102. Therefore, the convex lens 116 compensates for the reduced positive power of the first lens 123 and the second lens 133. Thus, the positive power of the optical system 102 can be increased.

[0158] 3.8 Convex lens

[0159] The convex lens 116 is a third plano-convex lens. Therefore, the convex lens 116 has a third plano lens surface 116a and a third convex lens surface 116b. The third plano lens surface 116a and the third convex lens surface 116b are located on opposite sides of each other. The third plano lens surface 116a is opposite to the second plano lens surface 133b of the second lens 133. The third convex lens surface 116b can be any one of a spherical surface, an aspherical surface, and a free-form surface.

[0160] The second reflective polarizing plate 131 and the second quarter wavelength plate 132 may be attached to the third planar lens surface 116 a as the second plane.

[0161] Since the convex lens 116 is a plano-convex lens, the cost of a mold required for manufacturing the convex lens 116 can be reduced compared to a case where the convex lens 116 is a biconvex lens.

[0162] 4 Second Embodiment

[0163] The following describes the differences between the second embodiment and the first embodiment. Regarding the points not described, the second embodiment also adopts the same configuration as that adopted in the first embodiment.

[0164] Figure 6 It is a cross-sectional view schematically showing a display device included in the head mounted device according to the second embodiment.

[0165] In a second embodiment, if Figure 6 As shown in the figure, the first quarter wavelength plate 122 is attached to one principal surface 111 a of the transparent plate 111 . In addition, the second quarter wavelength plate 132 is attached to the other principal surface 111 b of the transparent plate 111 .

[0166] Since the first quarter wavelength plate 122 and the second quarter wavelength plate 132 are attached to a common element of the transparent plate 111 , the accuracy of polarization compensation by the first quarter wavelength plate 122 and the second quarter wavelength plate 132 can be improved.

[0167] 5 Third Embodiment

[0168] The following describes the differences between the third embodiment and the first embodiment. Regarding the points not described, the third embodiment also adopts the same configuration as that adopted in the first embodiment.

[0169] Figure 7 1 is a cross-sectional view schematically showing a display device included in the head mounted device according to the third embodiment.

[0170] In a third embodiment, if Figure 7As shown, the first at least one optical element 113 includes a first cholesteric liquid crystal film 124 instead of the combination of the first reflective polarizing plate 121 and the first quarter-wave plate 122. In addition, the second at least one optical element 114 includes a second cholesteric liquid crystal film 134 instead of the combination of the second reflective polarizing plate 131 and the second quarter-wave plate 132.

[0171] The combination of the reflective polarizing plate and the quarter-wave plate has the property of selectively reflecting circularly polarized light having a specific rotation direction and emitting circularly polarized light having the specific rotation direction. The cholesteric liquid crystal film also has the property of selectively reflecting circularly polarized light having a specific rotation direction and emitting circularly polarized light having the specific rotation direction. Therefore, the cholesteric liquid crystal film can be used as a substitute for the combination of the reflective polarizing plate and the quarter-wave plate.

[0172] The first cholesteric liquid crystal film 124 is a first film-like optical element attached to the first flat lens surface 123b of the first lens 123 as the first plane. The first cholesteric liquid crystal film 124 has a first principal surface 124a and a second principal surface 124b. The first principal surface 124a and the second principal surface 124b are located on opposite sides to each other. The first principal surface 124a becomes the third surface 1133 of the first at least one optical element 113. The second principal surface 124b becomes the fourth surface 1134 of the first at least one optical element 113.

[0173] The second cholesteric liquid crystal film 134 is a second film-like optical element attached to the third flat lens surface 133b of the second lens 133 as the second plane. The second cholesteric liquid crystal film 134 has a first principal surface 134a and a second principal surface 134b. The first principal surface 134a and the second principal surface 134b are located on opposite sides to each other. The first principal surface 134a becomes the fifth surface 1145 of the second at least one optical element 114. The second principal surface 134b becomes the sixth surface 1146 of the second at least one optical element 114.

[0174] Figure 8 It is a diagram showing the relationship between a first convolution direction of a first cholesteric liquid crystal film included in a head mounted device according to a third embodiment and a second convolution direction of a second cholesteric liquid crystal film included in the head mounted device.

[0175] like Figure 8 As shown, the first cholesteric liquid crystal film 124 has a first rotation direction 124h. The liquid crystal molecules included in the first cholesteric liquid crystal film 124 have a structure that rotates in a spiral shape along the first rotation direction 124h. The second rotation direction DL is the same direction as the first rotation direction 124h. Therefore, the first cholesteric liquid crystal film 124 selectively reflects the circularly polarized light 184p having the second rotation direction DL.

[0176] The second cholesteric liquid crystal film 134 has a second rotation direction 134h opposite to the first rotation direction 124h. The liquid crystal molecules included in the second cholesteric liquid crystal film 134 have a structure that rotates in a spiral shape along the second rotation direction 134h. The first rotation direction DR is the same direction as the second rotation direction 134h. Therefore, the second cholesteric liquid crystal film 134 selectively reflects the circularly polarized light 184q having the first rotation direction DR.

[0177] 6 Fourth Embodiment

[0178] The following describes the differences between the fourth embodiment and the first embodiment. Regarding the points not described, the fourth embodiment also adopts the same configuration as that adopted in the first embodiment.

[0179] Fig. 9 1 is a cross-sectional view schematically showing a display device included in a head mounted device according to a fourth embodiment.

[0180] In a fourth embodiment, if Fig. 9 As shown, the first at least one optical element 113 includes a first polarizing volume hologram (PVH) film 125 instead of the combination of the first reflective polarizing plate 121 and the first quarter wavelength plate 122. In addition, the second at least one optical element 114 includes a second PVH film 135 instead of the combination of the second reflective polarizing plate 131 and the second quarter wavelength plate 132.

[0181] The combination of the reflective polarizing plate and the quarter-wave plate has the property of selectively reflecting circularly polarized light having a specific rotation direction and emitting circularly polarized light having the specific rotation direction. The PVH film also has the property of selectively reflecting circularly polarized light having a specific rotation direction and emitting circularly polarized light having the specific rotation direction. Therefore, the PVH film can be used as a substitute for the combination of the reflective polarizing plate and the quarter-wave plate.

[0182] The PVH film has many cholesteric liquid crystal molecules. Many cholesteric liquid crystal molecules are arranged in a direction inclined from the surface direction of the PVH film. Therefore, the PVH film can bend the optical path of circularly polarized light with a specific rotation direction so that the circularly polarized light is reflected off-axis or transmitted off-axis, and can transmit circularly polarized light with a rotation direction opposite to the specific rotation direction. Making light reflect off-axis means making the reflected light travel in a direction different from the direction in which the reflected light travels when the light is reflected regularly.

[0183] The first PVH film 125 is a first film-shaped optical element attached to the first flat lens surface 123b of the first lens 123 as the first plane. The first PVH film 125 has a first principal surface 125a and a second principal surface 125b. The first principal surface 125a and the second principal surface 125b are located on opposite sides of each other. The first principal surface 125a becomes the third surface 1133 of the first at least one optical element 113. The second principal surface 125b becomes the fourth surface 1134 of the first at least one optical element 113.

[0184] The second PVH film 135 is a second film-shaped optical element attached to the third flat lens surface 133b of the second lens 133 as the second plane. The second PVH film 135 has a first principal surface 135a and a second principal surface 135b. The first principal surface 135a and the second principal surface 135b are located on opposite sides to each other. The first principal surface 135a becomes the fifth surface 1145 of the second at least one optical element 114. The second principal surface 135b becomes the sixth surface 1146 of the second at least one optical element 114.

[0185] Figure 8 It is also a diagram showing the relationship between a first rotation direction of a first PVH film included in a head mount according to a fourth embodiment and a second rotation direction of a second PVH film included in the head mount.

[0186] The first PVH film 125 has a first rotation direction 125h. The liquid crystal molecules contained in the first PVH film 125 have a structure that rotates in a spiral shape along the first rotation direction 125h. The second rotation direction DL is the same direction as the first rotation direction 125h. Therefore, the first PVH film 125 selectively reflects the circularly polarized light 184p having the second rotation direction DL.

[0187] The second PVH film 135 has a second rotation direction 135h opposite to the first rotation direction 125h. The liquid crystal molecules included in the second PVH film 135 have a structure that rotates in a spiral shape along the second rotation direction 135h. The first rotation direction DR is the same direction as the second rotation direction 135h. Therefore, the second PVH film 135 selectively reflects the circularly polarized light 184q having the first rotation direction DR.

[0188] Preferably, the directions of arrangement of the many cholesteric liquid crystal molecules of each PVH film of the first PVH film 125 and the second PVH film 135 are changed within the plane of each PVH film so that each PVH film has a positive optical power like a concave mirror. Thus, positive optical power can be imparted to each PVH film having a flat shape. Thus, the positive optical power of the optical system 102 can be increased, and the optical system 102 can be made thinner.

[0189] 7 Fifth Embodiment

[0190] The following describes the differences between the fifth embodiment and the first embodiment. Regarding the points not described, the fifth embodiment also adopts the same configuration as that adopted in the first embodiment.

[0191] Fig.10 1 is a cross-sectional view schematically showing a display device included in a head mounted device according to a fifth embodiment.

[0192] In a fifth embodiment, if Fig.10 As shown in the figure, the optical system 102 includes a transparent plate 117 .

[0193] The transparent plate 117 has a main surface 117 a .

[0194] The transparent plate 117 is a glass plate or the like.

[0195] The first flat lens surface 123 b of the first lens 123 faces the first surface 112 a of the half mirror 112 . The first lens 123 is disposed between the transparent plate 117 and the half mirror 112 .

[0196] The second flat lens surface 133 b of the second lens 133 faces the second surface 112 b of the half mirror 112 .

[0197] The half mirror 112 is sandwiched between the first flat lens surface 123b of the first lens 123 and the second flat lens surface 133b of the second lens 133. The half mirror 112 is produced, for example, by evaporating a metal on the flat lens surface of one of the first lens 123 and the second lens 133 to produce a composite body of the first lens 123 and the second lens 133 and the half mirror 112, and bonding the produced composite body to the other of the first lens 123 and the second lens 133. The bonding of the composite body to the other of the first lens 123 and the second lens 133 is performed in such a manner that the first lens 123 and the second lens 133 become symmetrical with respect to the half mirror 112. The adhesive or the like is selected so that even if the distance from the half mirror 112 to the second lens 133 and the distance from the half mirror 112 to the first lens 123 become different due to the adhesive or the like, the symmetry is not substantially lost. The fifth embodiment is adopted when the complex body as a rigid body and the other lens of the first lens 123 and the second lens 133 as a rigid body can be bonded to each other by an adhesive or the like.

[0198] The first reflective polarizing plate 121 and the first quarter-wavelength plate 122 are attached to the principal surface 117 a of the transparent plate 117 , which is the first plane.

[0199] The second reflective polarizing plate 131 and the second quarter-wavelength plate 132 are attached to the third planar lens surface 116 a of the convex lens 116 as the second plane.

[0200] 8 Sixth Embodiment

[0201] The following describes the differences between the sixth embodiment and the fifth embodiment. Regarding the points not described, the sixth embodiment also adopts the same configuration as that adopted in the fifth embodiment.

[0202] Fig.11 1 is a cross-sectional view schematically showing a display device included in a head mounted device according to a sixth embodiment.

[0203] In the sixth embodiment, if Fig.11 As shown in the figure, the optical system 102 includes a transparent plate 111 .

[0204] Therefore, the optical system 102 includes a transparent plate 117 as a first transparent plate and a transparent plate 111 as a second transparent plate. The transparent plate 117 has a principal surface 117a as a first principal surface, and the transparent plate 111 has another principal surface 111b as a second principal surface.

[0205] The transparent plate 111 is disposed between the first flat lens surface 123 b of the first lens 123 and the second flat lens surface 133 b of the second lens 133 .

[0206] The half mirror 112 is disposed on the other principal surface 111 b of the transparent plate 111 .

[0207] Since the half mirror 112 is attached to the other main surface 111 b of the transparent plate 111 , the flatness of the half mirror 112 , which is important in the display device 12 adopting the dual path method, can be improved.

[0208] 9 Seventh Embodiment

[0209] The following describes the differences between the seventh embodiment and the fifth embodiment. Regarding the points not described, the seventh embodiment also adopts the same configuration as that adopted in the fifth embodiment.

[0210] Fig.12 1 is a cross-sectional view schematically showing a display device included in a head mounted device according to a seventh embodiment.

[0211] In the seventh embodiment, if Fig.12 As shown in the figure, the first quarter wavelength plate 122 is attached to the first flat lens surface 123b of the first lens 123. In addition, the second quarter wavelength plate 132 is attached to the second flat lens surface 133b of the second lens 133. In addition, the half mirror 112 is sandwiched between the first quarter wavelength plate 122 and the second quarter wavelength plate 132.

[0212] Since the first quarter wavelength plate 122 and the second quarter wavelength plate 132 are attached to a common element of the half mirror 112 , the accuracy of polarization compensation by the first quarter wavelength plate 122 and the second quarter wavelength plate 132 can be improved.

[0213] The seventh embodiment is adopted when the half mirror 112 can be arranged on the first quarter-wave plate 122 or the second quarter-wave plate 132 .

[0214] 10 Eighth Embodiment

[0215] The following describes the differences between the eighth embodiment and the fifth embodiment. Regarding the parts not described, the eighth embodiment also adopts the same configuration as that adopted in the fifth embodiment.

[0216] Fig.13 FIG. 1 is a cross-sectional view schematically showing a display device included in a head mounted device according to an eighth embodiment.

[0217] In an eighth embodiment, if Fig.13 As shown in the figure, the first at least one optical element 113 includes a first cholesteric liquid crystal film 124 instead of the combination of the first reflective polarizing plate 121 and the first quarter wavelength plate 122. In addition, the second at least one optical element 114 includes a second cholesteric liquid crystal film 134 instead of the combination of the second reflective polarizing plate 131 and the second quarter wavelength plate 132. The first cholesteric liquid crystal film 124 and the second cholesteric liquid crystal film 134 in the eighth embodiment are respectively the same cholesteric liquid crystal films as the first cholesteric liquid crystal film 124 and the second cholesteric liquid crystal film 134 in the third embodiment.

[0218] 11 Ninth Implementation Method

[0219] The following describes the differences between the ninth embodiment and the fifth embodiment. Regarding the parts not described, the ninth embodiment also adopts the same configuration as that adopted in the fifth embodiment.

[0220] Fig.14 This is also a cross-sectional view schematically illustrating a display device included in the head mounted device according to the ninth embodiment.

[0221] In the ninth embodiment, if Fig.14As shown in the figure, the first at least one optical element 113 includes a first PVH film 125 instead of the combination of the first reflective polarizing plate 121 and the first quarter wavelength plate 122. In addition, the second at least one optical element 114 includes a second PVH film 135 instead of the combination of the second reflective polarizing plate 131 and the second quarter wavelength plate 132. The first PVH film 125 and the second PVH film 135 in the ninth embodiment are respectively the same PVH films as the first PVH film 125 and the second PVH film 135 in the fourth embodiment.

[0222] The present disclosure is not limited to the above-described embodiments, and may be replaced with a configuration that is substantially the same as the configuration shown in the above-described embodiments, a configuration that produces the same function and effect, or a configuration that can achieve the same purpose.

Claims

1. An optical system, characterized in that: have: a semi-reflective mirror having a first surface and a second surface located on opposite sides of each other; The at least one first optical element includes a first film-shaped optical element attached to a first plane, and has a third surface and a fourth surface located on opposite sides to each other, the third surface is opposite to the first surface, when first linearly polarized light having a first polarization direction is incident on the fourth surface, first circularly polarized light having a first rotation direction is emitted from the third surface, and when second circularly polarized light having a second rotation direction different from the first rotation direction is incident on the third surface, third circularly polarized light having the second rotation direction is emitted from the third surface; a second at least one optical element, comprising a second film-shaped optical element attached to a second plane, having a fifth surface and a sixth surface located on opposite sides to each other, the fifth surface being opposite to the second surface, and emitting a fifth circularly polarized light having the first polarization direction from the fifth surface when a fourth circularly polarized light having the first rotation direction is incident on the fifth surface, and emitting a second linearly polarized light having a second polarization direction perpendicular to the first polarization direction from the sixth surface when a sixth circularly polarized light having the second rotation direction is incident on the fifth surface, the second at least one optical element being arranged at a position symmetrical to the position where the first at least one optical element is arranged with respect to the half mirror, and having a shape symmetrical to the shape of the first at least one optical element with respect to the half mirror; as well as The convex lens transmits the second linearly polarized light.

2. The optical system according to claim 1, wherein: The first at least one optical element comprises a first lens, The second at least one optical element includes a second lens that is arranged at a position symmetrical to the position where the first lens is arranged with respect to the half mirror and has a shape symmetrical to the shape of the first lens with respect to the half mirror.

3. The optical system according to claim 2, wherein: The first lens is a first plano-convex lens having a first plano lens surface and a first convex lens surface located on opposite sides to each other, The second lens is a second plano-convex lens having a second plano lens surface and a second convex lens surface located on opposite sides to each other.

4. The optical system according to claim 3, wherein: The first convex lens surface is opposite to the first surface, The second convex lens surface is opposite to the second surface, The first plane is the first plano lens surface, The second plane is the second planar lens surface.

5. The optical system according to claim 4, wherein: A transparent plate having a main surface and arranged between the first convex lens surface and the second convex lens surface is provided. The half mirror is arranged on the main surface.

6. The optical system according to claim 3, wherein: The first convex lens surface is opposite to the first surface, The second convex lens surface is opposite to the second surface, The convex lens is a third plano-convex lens having a third plano lens surface and a third convex lens surface located on opposite sides to each other, and the third plano lens surface is opposite to the second plano lens surface, The first plane is the first plano lens surface, The second plane is the third plano lens surface.

7. The optical system according to claim 6, wherein: A transparent plate having a main surface and arranged between the first convex lens surface and the second convex lens surface is provided. The half mirror is arranged on the main surface.

8. The optical system according to claim 3, wherein: A transparent plate having a main surface, The first plano-convex lens is disposed between the transparent plate and the half mirror. The first plane lens surface is opposite to the first surface, The second flat lens surface is opposite to the second surface, The convex lens is a third plano-convex lens having a third plano lens surface and a third convex lens surface located on opposite sides to each other, and the third plano lens surface is opposite to the second convex lens surface, The first plane is the main surface, The second plane is the third plano lens surface.

9. The optical system according to claim 8, wherein: The half mirror is sandwiched between the first flat lens surface and the second flat lens surface.

10. The optical system according to claim 8, wherein: The transparent plate is a first transparent plate, The main surface is a first main surface, The optical system includes a second transparent plate, the second transparent plate having a second principal surface and arranged between the first plano lens surface and the second plano lens surface. The half mirror is arranged on the second main surface.

11. The optical system according to any one of claims 1 to 10, wherein: The first film-like optical element is a first reflective polarizing plate having the fourth surface and having a first transmission axis and a first reflection axis. The at least one first optical element includes a first quarter wavelength plate, which is disposed between the half mirror and the first reflective polarizing plate, has the third surface and has a first fast axis and a first slow axis. The second film-like optical element is a second reflective polarizing plate, the second reflective polarizing plate has the sixth surface and has a second transmission axis and a second reflection axis, the second transmission axis is perpendicular to the first transmission axis, and the second reflection axis is perpendicular to the first reflection axis. The second at least one optical element includes a second 1 / 4 wavelength plate, which is arranged between the half-mirror and the second reflective polarizing plate, has the fifth surface and has a second fast phase axis and a second slow phase axis, the second fast phase axis is perpendicular to the first fast phase axis, and the second slow phase axis is perpendicular to the first slow phase axis.

12. The optical system according to claim 11, wherein: The first at least one optical element includes a first plano-convex lens, the first plano-convex lens having a first plano lens surface and a first convex lens surface located on opposite sides of each other, the first convex lens surface being opposite to the first surface, The second at least one optical element comprises a second plano-convex lens, wherein the second plano-convex lens has a second plano lens surface and a second convex lens surface located on opposite sides to each other, and the second convex lens surface is opposite to the second surface. The first plane is the first plano lens surface, The second plane is the second plano lens surface, The first quarter wavelength plate is attached to the first flat lens surface. The second quarter wavelength plate is attached to the second flat lens surface.

13. The optical system according to claim 11, wherein: The first at least one optical element includes a first plano-convex lens, the first plano-convex lens having a first plano lens surface and a first convex lens surface located on opposite sides of each other, the first convex lens surface being opposite to the first surface, The second at least one optical element comprises a second plano-convex lens, wherein the second plano-convex lens has a second plano lens surface and a second convex lens surface located on opposite sides to each other, and the second convex lens surface is opposite to the second surface. The convex lens is a third plano-convex lens having a third plano lens surface and a third convex lens surface located on opposite sides to each other, and the third plano lens surface is opposite to the second plano lens surface, The first plane is the first plano lens surface, The second plane is the third plano lens surface, The first quarter wavelength plate is attached to the first flat lens surface. The second quarter wavelength plate is attached to the third plano lens surface.

14. The optical system according to claim 11, wherein: The first at least one optical element includes a first plano-convex lens, the first plano-convex lens having a first plano lens surface and a first convex lens surface located on opposite sides of each other, the first convex lens surface being opposite to the first surface, The second at least one optical element comprises a second plano-convex lens, wherein the second plano-convex lens has a second plano lens surface and a second convex lens surface located on opposite sides to each other, and the second convex lens surface is opposite to the second surface. The optical system includes a transparent plate having one principal surface and another principal surface located on opposite sides to each other and arranged between the first convex lens surface and the second convex lens surface. The first plane is the first plano lens surface, The second plane is the second plano lens surface, The first quarter wavelength plate is attached to the one main surface, The second quarter wavelength plate is attached to the other main surface. The half mirror is arranged on the one main surface or the other main surface.

15. The optical system according to claim 11, wherein: The first at least one optical element includes a first plano-convex lens, the first plano-convex lens having a first plano lens surface and a first convex lens surface located on opposite sides of each other, the first convex lens surface being opposite to the first surface, The second at least one optical element comprises a second plano-convex lens, wherein the second plano-convex lens has a second plano lens surface and a second convex lens surface located on opposite sides to each other, and the second convex lens surface is opposite to the second surface. The convex lens is a third plano-convex lens having a third plano lens surface and a third convex lens surface located on opposite sides to each other, and the third plano lens surface is opposite to the second plano lens surface, The optical system includes a transparent plate having one principal surface and another principal surface located on opposite sides to each other and arranged between the first convex lens surface and the second convex lens surface. The first plane is the first plano lens surface, The second plane is the third plano lens surface, The first quarter wavelength plate is attached to the one main surface, The second quarter wavelength plate is attached to the other main surface. The half mirror is arranged on the one main surface or the other main surface.

16. The optical system according to claim 11, wherein: A transparent plate having a main surface, The at least one first optical element includes a first plano-convex lens, the first plano-convex lens having a first plano lens surface and a first convex lens surface located on opposite sides of each other, the first plano lens surface is opposite to the first surface, and the first plano-convex lens is arranged between the transparent plate and the half mirror. The second at least one optical element comprises a second plano-convex lens, the second plano-convex lens having a second plano lens surface and a second convex lens surface located on opposite sides to each other, the second plano lens surface being opposite to the second surface, The convex lens is a third plano-convex lens having a third plano lens surface and a third convex lens surface located on opposite sides to each other, and the third plano lens surface is opposite to the second convex lens surface, The first plane is the main surface, The second plane is the third plano lens surface, The first quarter wavelength plate is attached to the main surface. The second quarter wavelength plate is attached to the third flat lens surface. The half mirror is sandwiched between the first flat lens surface and the second flat lens surface.

17. The optical system according to claim 11, wherein: A first transparent plate having a first main surface and a second transparent plate having a second main surface are provided. The first at least one optical element includes a first plano-convex lens, the first plano-convex lens having a first plano lens surface and a first convex lens surface located on opposite sides of each other, the first plano lens surface is opposite to the first surface, and the first plano-convex lens is arranged between the first transparent plate and the half mirror. The second at least one optical element comprises a second plano-convex lens, the second plano-convex lens having a second plano lens surface and a second convex lens surface located on opposite sides to each other, the second plano lens surface being opposite to the second surface, The convex lens is a third plano-convex lens having a third plano lens surface and a third convex lens surface located on opposite sides to each other, and the third plano lens surface is opposite to the second convex lens surface, The second transparent plate is disposed between the first flat lens surface and the second flat lens surface. The first plane is the first main surface, The second plane is the third plano lens surface, The first quarter wavelength plate is attached to the first main surface. The second quarter wavelength plate is attached to the third flat lens surface. The half mirror is arranged on the second main surface.

18. The optical system according to claim 11, wherein: A transparent plate having a main surface, The at least one first optical element includes a first plano-convex lens, the first plano-convex lens having a first plano lens surface and a first convex lens surface located on opposite sides of each other, the first plano lens surface is opposite to the first surface, and the first plano-convex lens is arranged between the transparent plate and the half mirror. The second at least one optical element comprises a second plano-convex lens, the second plano-convex lens having a second plano lens surface and a second convex lens surface located on opposite sides to each other, the second plano lens surface being opposite to the second surface, The convex lens is a third plano-convex lens having a third plano lens surface and a third convex lens surface located on opposite sides to each other, and the third plano lens surface is opposite to the second convex lens surface, The first plane is the main surface, The second plane is the third plano lens surface, The first quarter wavelength plate is attached to the first flat lens surface. The second quarter wavelength plate is attached to the second flat lens surface. The half mirror is sandwiched between the first 1 / 4 wavelength plate and the second 1 / 4 wavelength plate.

19. An optical system according to any one of claims 1 to 10, wherein: The first film-like optical element is a first cholesteric liquid crystal film having the third surface and the fourth surface and having a first rotation direction, The second film-like optical element is a second cholesteric liquid crystal film having the fifth surface and the sixth surface and having a second rotation direction different from the first rotation direction.

20. The optical system according to any one of claims 1 to 10, wherein: The first film-like optical element is a first polarizing holographic film having the third surface and the fourth surface and having a first rotation direction. The second film-like optical element is a second polarizing holographic film having the fifth surface and the sixth surface and having a second rotation direction different from the first rotation direction.

21. A display device, characterized in that: have: The optical system of any one of claims 1 to 10; and A display emits the first linearly polarized light.

22. A head mounted device, characterized in that: A display device according to claim 21 is provided.

Images