Display device

Abstract

The invention relates to a display device. According to one embodiment, a display device includes: a display element; a first phase difference plate overlapping the display element; an optical element overlapping the display element and the first phase difference plate and having a lens effect; a second retardation plate overlapping the optical element and having a first main surface; and a reflective polarizing plate that overlaps the second phase difference plate and has a second main surface that is not in direct contact with the first main surface and is rotatable relative to the first main surface.

Description

[0001] Related Applications

[0002] This application claims the benefit of priority based on Japanese Patent Application No. 2023-097089 filed on June 13, 2023, and cites all the contents described in the Japanese patent application. Technical Field

[0003] An embodiment of the present invention relates to a display device. Background Art

[0004] In recent years, technologies that use head-mounted displays worn on the user's head to provide, for example, virtual reality (VR) have attracted attention. The head-mounted display is configured to display images on a display placed in front of the user's eyes. As a result, the user wearing the head-mounted display can experience a virtual reality space with a sense of presence.

[0005] In such a display device, it is desirable to reduce stray light caused by undesired reflected light from the viewpoint of improving display quality. Summary of the invention

[0006] An object of the embodiment is to provide a display device capable of suppressing a decrease in display quality.

[0007] According to one embodiment, a display device includes:

[0008] A display element; a first phase difference plate overlapping the display element; an optical element overlapping the display element and the first phase difference plate and having a lens effect; a second phase difference plate overlapping the optical element and having a first principal surface; and a reflective polarizing plate overlapping the second phase difference plate and having a second principal surface, the second principal surface is not in direct contact with the first principal surface, is opposite to the first principal surface and can rotate.

[0009] According to the embodiment, a display device capable of suppressing a decrease in display quality can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 1 is a perspective view showing an example of the appearance of glasses 1 to which the display device DSP according to the present embodiment is applied.

[0011] Figure 2 It is shown Figure 1 A diagram showing an example of the configuration of a display device DSP.

[0012] Figure 3 It is shown that it can be applied to Figure 2 The diagram shows an example of the configuration of a display element DE of a display device DSP shown.

[0013] Figure 4 It is used to illustrate Figure 2 A diagram showing the optical effects of the display device DSP is shown.

[0014] Figure 5 It is a diagram for explaining the first axis angle θ1 and the second axis angle θ2.

[0015] Figure 6 1 is a diagram showing a configuration example of the adjustment mechanism 3 for adjusting the rotation angle of the second transparent support body BS2.

[0016] Figure 7 It is a diagram showing another configuration example of the adjustment mechanism 3 for adjusting the rotation angle of the second transparent supporting body BS2.

[0017] Figure 8 It is used to illustrate Figure 2 A diagram showing reflected light at an interface included in a display device DSP is shown.

[0018] Fig. 9 This is a diagram for explaining reflected light at an interface included in a display device DSP as a comparative example.

[0019] Fig.10 It is shown Figure 1 FIG. 2 is a diagram showing another configuration example of a DSP of a display device shown in FIG.

[0020] Fig.11 It is shown Figure 1 FIG. 2 is a diagram showing another configuration example of a DSP of a display device shown in FIG.

[0021] Fig.12 It is a figure which shows the simulation result. DETAILED DESCRIPTION

[0022] Hereinafter, the present embodiment will be described with reference to the accompanying drawings. It should be noted that the disclosure is only an example, and appropriate changes that are easy for a person skilled in the art to think of within the scope of the main idea of ​​the present invention are of course also included in the scope of the present invention. In addition, the accompanying drawings sometimes schematically represent the width, thickness, shape, etc. of each part compared to the actual method in order to make the description clearer, which is only an example and does not limit the interpretation of the present invention. In addition, in this specification and each figure, the same figure mark is marked for the components that are the same as the parts described in the figures that have appeared or have similar functions, and repeated detailed descriptions are sometimes appropriately omitted.

[0023] It should be noted that, in the drawings, mutually orthogonal X-axis, Y-axis and Z-axis are recorded as needed for ease of understanding. The direction along the X-axis is referred to as the first direction X, the direction along the Y-axis is referred to as the second direction Y, and the direction along the Z-axis is referred to as the third direction Z. The X-axis, Y-axis and Z-axis may also intersect at an angle other than 90°. The plane defined by the X-axis and the Y-axis is referred to as the XY plane, and observing the XY plane is referred to as top view.

[0024] Figure 1 1 is a perspective view showing an example of the appearance of glasses 1 to which the display device DSP according to the present embodiment is applied.

[0025] The glasses 1 include, for example, a display device DSPR for the right eye and a display device DSPL for the left eye. The display devices DSPR and DSPL are arranged in the second direction Y. Such glasses 1 can be used, for example, to provide virtual reality, augmented reality, and the like.

[0026] The display devices DSPR and DSPL have substantially the same configuration and will be described below simply as the display device DSP.

[0027] Figure 2 It is shown Figure 1 A diagram showing an example of the configuration of a display device DSP.

[0028] The display device DSP includes a display element DE, a first phase difference plate R1, a holographic optical element HE, a second phase difference plate R2, and a reflective polarizing plate RP. The display element DE, the first phase difference plate R1, the holographic optical element HE, the second phase difference plate R2, and the reflective polarizing plate RP are all formed in a flat plate shape along the XY plane. As will be described in detail later, at least one of the second phase difference plate R2 and the reflective polarizing plate RP is configured to be rotatable in the XY plane.

[0029] The display element DE includes an illumination device IL, a liquid crystal panel PNL, a first polarizing plate P1, and a second polarizing plate P2. The first polarizing plate P1 is arranged between the illumination device IL and the liquid crystal panel PNL in the third direction Z. The liquid crystal panel PNL is arranged between the first polarizing plate P1 and the second polarizing plate P2 in the third direction Z. The transmission axis T1 of the first polarizing plate P1 and the transmission axis T2 of the second polarizing plate P2 are orthogonal to each other. In one example, the transmission axis T1 is parallel to the first direction X, and the transmission axis T2 is parallel to the second direction Y. Such a display element DE is configured to emit display light DL of linearly polarized light from the second polarizing plate P2. The polarization axis of the display light DL when emitted from the second polarizing plate P2 is parallel to the transmission axis T2. The display light DL when emitted from the second polarizing plate P2 is, for example, divergent light.

[0030] It should be noted that the configuration of the display element DE is not limited to the example shown in the figure. For example, the display element DE may also be a display panel having a self-luminous light-emitting element such as an organic electroluminescent (EL) element, a micro LED, or a mini LED. When the display element DE is a display panel having a light-emitting element, the lighting device and the first polarizing plate are omitted.

[0031] The first phase difference plate R1 overlaps with the display element DE in the third direction Z. In the example shown in the figure, the first phase difference plate R1 overlaps with the second polarizing plate P2 and is fixed to the second polarizing plate P2. Such a first phase difference plate R1 is a 1 / 4 wavelength plate and gives a phase difference of 1 / 4 wavelength to the light of a specified wavelength transmitted. It will be described later that the slow axis of the first phase difference plate R1 intersects with the transmission axis T1 of the first polarizing plate P1 at an angle of approximately 45°.

[0032] In this specification, the state of "overlapping" of two parts is defined as a state in which a part of another part exists on the normal line of one part. And, the state of "overlapping" includes a state in which the two parts are in contact with each other, a state in which the two parts are bonded to each other, and a state in which a space or another part exists between the two parts.

[0033] The holographic optical element HE is equivalent to an example of an optical element having a lens effect. The holographic optical element HE overlaps with the display element DE and the first phase difference plate R1 in the third direction Z. The holographic optical element HE is a resin film having a pattern of interference fringes recorded thereon, and has a lens effect of diffracting incident light of a specific wavelength in a predetermined direction and focusing the incident light.

[0034] The second phase difference plate R2 overlaps with the holographic optical element HE in the third direction Z. In one example, the second phase difference plate R2 is stacked on the holographic optical element HE. Such a second phase difference plate R2 is a 1 / 4 wavelength plate, and gives a phase difference of 1 / 4 wavelength to the light of a specified wavelength transmitted. It will be described later that the slow axis of the second phase difference plate R2 intersects the transmission axis T2 of the second polarizing plate P2 at an angle of approximately 45°, and is orthogonal to the slow axis of the first phase difference plate R1.

[0035] The first transparent support BS1 is formed in a flat plate shape and has a first surface S1 facing the first phase difference plate R1 in the third direction Z and a second surface S2 on the opposite side of the first surface S1. The first surface S1 and the second surface S2 are both planes parallel to the XY plane. In the example shown in the figure, the stack of the holographic optical element HE and the second phase difference plate R2 is arranged on the second surface S2.

[0036] It should be noted that the stacked body of the hologram optical element HE and the second phase difference plate R2 may be arranged on the first surface S1. Alternatively, the hologram optical element HE may be arranged on the first surface S1, and the second phase difference plate R2 may be arranged on the second surface S2.

[0037] The reflective polarizing plate RP overlaps with the second phase difference plate R2 via the air layer A in the third direction Z. As the reflective polarizing plate RP, a multilayer thin film polarizing plate, a wire grid polarizing plate, etc. can be applied. Such a reflective polarizing plate RP is configured to reflect the first linear polarized light and transmit the second linear polarized light different from the first linear polarized light. The transmission axis Trp of the reflective polarizing plate RP is orthogonal to the transmission axis T2 of the second polarizing plate P2. In one example, the transmission axis Trp is parallel to the first direction X, the polarization axis of the first linear polarized light is orthogonal to the transmission axis Trp, and the polarization axis of the second linear polarized light is parallel to the transmission axis Trp.

[0038] The second transparent support BS2 is formed in a flat plate shape and has a third surface S3 and a fourth surface S4 on the opposite side of the third surface S3. The third surface S3 and the fourth surface S4 are both planes parallel to the XY plane. The reflective polarizing plate RP is arranged on the third surface S3. It should be noted that the reflective polarizing plate RP can also be arranged on the fourth surface S4.

[0039] The first transparent support BS1 and the second transparent support BS2 are glass substrates or resin substrates.

[0040] The optical function of the display device DSP is briefly described below.

[0041] As shown by the dotted line, the display light DL emitted from the display element DE passes through the first phase difference plate R1, then passes through the first transparent support BS1, the holographic optical element HE and the second phase difference plate R2, and is reflected by the reflective polarizing plate RP via the air layer A. The display light DL reflected by the reflective polarizing plate RP passes through the second phase difference plate R2 via the air layer A, and is reflected by the holographic optical element HE. The display light DL reflected by the holographic optical element HE passes through the second phase difference plate R2, then passes through the reflective polarizing plate RP via the air layer A, and further passes through the second transparent support BS2, and is focused on the pupil E of the user by the lens action of the holographic optical element HE.

[0042] Figure 3 It is shown that it can be applied to Figure 2 The diagram shows an example of the configuration of a display element DE of a display device DSP shown.

[0043] The display element DE includes a liquid crystal panel PNL, an illumination device IL, and a prism sheet PS. The prism sheet PS is disposed between the liquid crystal panel PNL and the illumination device IL in the third direction Z.

[0044] The liquid crystal panel PNL is a transmissive type and includes a first substrate SUB1, a second substrate SUB2, and a liquid crystal layer LC. The liquid crystal layer LC is held between the first substrate SUB1 and the second substrate SUB2 in the third direction Z and is sealed by a sealant SE.

[0045] The liquid crystal panel PNL is arranged between the lighting device IL and the first phase difference plate R1 in the third direction Z. The first polarizing plate P1 is arranged between the lighting device IL and the liquid crystal panel PNL in the third direction Z, for example, bonded to the first substrate SUB1. The second polarizing plate P2 is arranged between the liquid crystal panel PNL and the first phase difference plate R1 in the third direction Z, for example, bonded to the second substrate SUB2.

[0046] The display portion DA is a region configured to display an image on the liquid crystal panel PNL.

[0047] The lighting device IL includes a light guide plate LG and a light source LS. The light guide plate LG faces the prism sheet PS in the third direction Z. The light source LS faces the side surface LGa of the light guide plate LG in the first direction X. Although not described in detail, the light source LS includes a light emitting element configured to emit light of a blue wavelength, a light emitting element configured to emit light of a green wavelength, and a light emitting element configured to emit light of a red wavelength. As these light emitting elements, for example, laser elements can be applied.

[0048] The light emitted from the light source LS propagates while being totally reflected inside the light guide plate LG. The light that deviates from the total reflection condition in the propagated light is emitted from the light guide plate LG toward the liquid crystal panel PNL. The light emitted from the light guide plate LG is refracted by the prism sheet PS to form illumination light emitted along the third direction Z. The liquid crystal panel PNL selectively modulates the illumination light in the display unit DA. Then, a part of the illumination light forms display light DL of linear polarized light when passing through the second polarizing plate P2.

[0049] Figure 4 It is used to illustrate Figure 2 A diagram showing the optical effects of the display device DSP is shown.

[0050] First, the display light DL of the first linear polarized light LP1 passing through the second polarizing plate P2 of the display element DE passes through the first phase difference plate R1 and is converted into the first circular polarized light CP1. The first circular polarized light CP1 passing through the first phase difference plate R1 passes through the holographic optical element HE, and then passes through the second phase difference plate R2 and is converted into the first linear polarized light LP1. It should be noted that the first circular polarized light CP1 reflected by the holographic optical element HE in the first circular polarized light CP1 passing through the first phase difference plate R1 passes through the first phase difference plate R1 again and is converted into the second linear polarized light LP2, and then is absorbed by the second polarizing plate P2. The second linear polarized light LP2 is a linear polarized light having a polarization axis orthogonal to the first linear polarized light LP1.

[0051] The first linear polarized light LP1 passing through the second phase difference plate R2 is reflected by the reflective polarizing plate RP. The first linear polarized light LP1 reflected by the reflective polarizing plate RP passes through the second phase difference plate R2 and is converted into the second circularly polarized light CP2. The second circularly polarized light CP2 is circularly polarized light in the opposite direction to the first circularly polarized light CP1.

[0052] The second circularly polarized light CP2 passing through the second phase difference plate R2 is reflected and diffracted by the holographic optical element HE. The second circularly polarized light CP2 reflected by the holographic optical element HE passes through the second phase difference plate R2 and is converted into the second linearly polarized light LP2. It should be noted that the second circularly polarized light CP2 passing through the holographic optical element HE in the second circularly polarized light CP2 passing through the second phase difference plate R2 is not reflected to the user side and does not contribute to display.

[0053] The second linearly polarized light LP2 reflected by the hologram optical element HE and then transmitted through the second phase difference plate R2 passes through the reflective polarization plate RP, and is focused on the pupil E of the user by the lens action of the hologram optical element HE.

[0054] It should be noted that the reference Figure 4 The first linear polarized light LP1 described above is replaced by the second linear polarized light LP2 , and the first circularly polarized light CP1 may be replaced by the second circularly polarized light CP2 .

[0055] According to such a configuration example, compared with an optical system including optical components formed of glass, resin, etc., the thickness along the third direction Z can be reduced and the weight can be reduced. Therefore, it is possible to miniaturize the display device DSP.

[0056] However, through Figure 4 Light reaching pupil E through a different optical path than the one indicated by the solid line in the figure becomes so-called stray light, which results in a decrease in display quality. Figure 4 In the example shown, from the viewpoint of suppressing stray light, it is important that the first linear polarized light LP1 of the light from the second phase difference plate R2 toward the reflective polarizing plate RP after passing through the holographic optical element HE is orthogonal to the transmission axis Trp of the reflective polarizing plate RP with high precision. In the case where the first linear polarized light LP1 of the light from the second phase difference plate R2 toward the reflective polarizing plate RP is not orthogonal to the transmission axis Trp of the reflective polarizing plate RP with high precision, a part of the light will be transmitted and stray light will be generated. As one of the reasons why the first linear polarized light LP1 is not orthogonal to the transmission axis Trp of the reflective polarizing plate RP with high precision, the mismatch between the first axis angle between the transmission axis T2 of the second polarizing plate P2 and the slow axis of the first phase difference plate R1 and the second axis angle between the transmission axis Trp of the reflective polarizing plate RP and the slow axis of the second phase difference plate R2 can be cited.

[0057] Therefore, in this embodiment, the second polarizing plate P2 and the first phase difference plate R1 are fixed to each other, while the reflective polarizing plate RP and the second phase difference plate R2 are respectively configured to be relatively rotatable on the XY plane. This will be described in more detail below.

[0058] Figure 5 It is a diagram for explaining the first axis angle θ1 and the second axis angle θ2.

[0059] As described above, the transmission axis T2 of the second polarizing plate P2 is, for example, parallel to the second direction Y. The slow axis AX1 of the first phase difference plate R1 intersects the transmission axis T2 or the second direction Y on the XY plane. The first axis angle θ1 is equivalent to the angle between the transmission axis T2 and the slow axis AX1. In order to convert the first linearly polarized light LP1 transmitted through the second polarizing plate P2 into the first circularly polarized light CP1, the first axis angle θ1 is set to 45°.

[0060] The transmission axis Trp of the reflective polarizing plate RP is, for example, parallel to the first direction X. The slow axis AX2 of the second phase difference plate R2 intersects the transmission axis Trp or the first direction X on the XY plane. The second axis angle θ2 is equivalent to the angle between the transmission axis Trp and the slow axis AX2. The second axis angle θ2 is set to be the same as the first axis angle θ1, and is set to 45° here.

[0061] It should be noted that the third axis angle θ3 corresponding to the angle formed by the slow axis AX1 and the slow axis AX2 is set to 90°.

[0062] In order to achieve a state where the first linear polarized light LP1 is orthogonal to the transmission axis Trp of the reflective polarizing plate RP with high precision, it is sufficient to match the first axis angle θ1 with the second axis angle θ2. Therefore, at least one of the second phase difference plate R2 and the reflective polarizing plate RP is configured to be rotatable on the XY plane. In the event of a mismatch between the first axis angle θ1 and the second axis angle θ2, the second axis angle θ2 can be matched with the first axis angle θ1 by rotating at least one of the second phase difference plate R2 and the reflective polarizing plate RP. In this way, it is possible to suppress unwanted stray light and suppress degradation of display quality.

[0063] An example of rotating the second transparent support BS2 on which the reflective polarizing plate RP is disposed will be described below.

[0064] Figure 6 1 is a diagram showing a configuration example of the adjustment mechanism 3 for adjusting the rotation angle of the second transparent support body BS2.

[0065] In the glasses 1, the display device DSPR for the right eye and the display device DSPL for the left eye are respectively held on the frame 2. In each of the display device DSPR and the display device DSPL, the second transparent support body BS2 provided with the reflective polarizing plate RP is formed into a circular shape. For example, the second transparent support body BS2 of the display device DSPR has a circular outer edge Ebs as shown in an enlarged manner. The turntable type adjustment mechanism 3 has a circular contact portion 3a in contact with the outer edge Ebs.

[0066] In the example shown in the figure, when the adjustment mechanism 3 rotates to the right, the second transparent support BS2 rotates to the left with its center Obs as the rotation axis. That is, the rotation angle of the second transparent support BS2 can be adjusted by the adjustment mechanism 3. As the second transparent support BS2 rotates, the reflective polarizing plate RP also rotates. Thus, the orientation of the transmission axis Trp of the reflective polarizing plate RP in the XY plane can be adjusted.

[0067] For example, when the diameter of the second transparent support BS2 is 60 mm and the diameter of the contact portion 3 a is 6 mm, when the adjustment mechanism 3 rotates 10°, the second transparent support BS2 and the reflective polarizing plate RP rotate 1°.

[0068] It should be noted that, although not shown in the drawings, the first transparent support body BS1 on which the second phase difference plate R2 is arranged is fixed to the frame 2 so as not to rotate.

[0069] In this way, by rotating the reflective polarizing plate RP relative to the fixed second phase difference plate R2, the second axis angle θ2 can be finely adjusted, and the second axis angle θ2 can be matched with the first axis angle θ1.

[0070] Figure 7 It is a diagram showing another configuration example of the adjustment mechanism 3 for adjusting the rotation angle of the second transparent supporting body BS2.

[0071] In each of the display device DSPR and the display device DSPL, the second transparent support BS2 provided with the reflective polarizing plate RP is formed in a non-circular shape. For example, as shown in an enlarged form, the second transparent support BS2 of the display device DSPR is formed in a substantially quadrilateral shape and has four sides E1 to E4 as an outer edge Ebs. Side E1 is opposite to side E3, and side E2 is opposite to side E4.

[0072] The screw type adjustment mechanism 3 is connected to the vicinity of the side E1 of the side E2. The vicinity of the corner where the side E3 and the side E4 intersect is connected to the fixing point 4 of the frame 2. Elastic bodies 5 such as springs are respectively present between the side E1 and the frame 2 and between the side E4 and the frame 2.

[0073] In the example shown in the figure, when the adjustment mechanism 3 is rotated and pressed toward the side E2, the second transparent support body BS2 rotates counterclockwise with the fixed point 4 as the rotation axis. In other words, the rotation angle of the second transparent support body BS2 can be adjusted by the adjustment mechanism 3. As the second transparent support body BS2 rotates, the reflective polarizing plate RP also rotates. Thus, the orientation of the transmission axis Trp of the reflective polarizing plate RP in the XY plane can be adjusted.

[0074] For example, when the second transparent supporting body BS2 is a square, the length of each side E1 to E4 is 50 mm, the thread diameter of the adjustment mechanism 3 is 2 mm, and the pitch of the adjustment mechanism 3 is 0.25 mm, when the adjustment mechanism 3 rotates 1°, the second transparent supporting body BS2 and the reflective polarizing plate RP rotate 0.46°.

[0075] It should be noted that, although not shown in the drawings, the first transparent support body BS1 on which the second phase difference plate R2 is arranged is fixed to the frame 2 so as not to rotate.

[0076] In this way, by rotating the reflective polarizing plate RP relative to the fixed second phase difference plate R2, the second axis angle θ2 can be finely adjusted, and the second axis angle θ2 can be matched with the first axis angle θ1.

[0077] In addition, Figure 6 and Figure 7 In each of the configuration examples shown, the second transparent support BS2 may be fixed to the frame 2, and the first transparent support BS1 may be rotated by the adjustment mechanism 3. In this case, the second axis angle θ2 can be finely adjusted by rotating the second phase difference plate R2 relative to the fixed reflective polarizing plate RP.

[0078] Next, the influence of reflection at the interface included in the DSP of the display device is discussed.

[0079] Figure 8 It is used to illustrate Figure 2 A diagram showing reflected light at an interface included in a display device DSP is shown.

[0080] The interfaces discussed here refer to the interface B1 between the second phase difference plate R2 and the air layer A, and the interface B2 between the reflective polarizing plate RP and the air layer A.

[0081] When part of the light traveling from the hologram optical element HE toward the second phase difference plate R2 is reflected at the interface B1, the reflected light is not reflected toward the pupil E and does not contribute to display.

[0082] When part of the light from the second phase difference plate R2 toward the reflective polarizing plate RP is reflected at the interface B2, the reflected light does not reach the pupil E and does not contribute to the display.

[0083] When part of the light from the reflective polarizing plate RP toward the second phase difference plate R2 is reflected at the interface B2, the reflected light maintains the polarization state of the first linear polarized light, does not pass through the reflective polarizing plate RP, and does not contribute to display.

[0084] When part of the light from the reflective polarizing plate RP toward the second phase difference plate R2 is reflected at the interface B1, the reflected light also does not pass through the reflective polarizing plate RP and does not contribute to display.

[0085] That is, according to the present embodiment, in addition to being able to suppress stray light caused by the mismatch between the first axis angle θ1 and the second axis angle θ2 , it is also possible to suppress stray light caused by undesired reflection at the interfaces B1 and B2 .

[0086] Fig. 9 This is a diagram for explaining reflected light at an interface included in a display device DSP as a comparative example.

[0087] The comparative example shown in the figure is Figure 8 Compared with the present embodiment shown in the figure, the difference is that the second phase difference plate R2 and the reflective polarizer RP are stacked, and there is an air layer A between the holographic optical element HE and the second phase difference plate R2. The interface discussed here refers to the interface B11 between the holographic optical element HE and the air layer A, and the interface B12 between the second phase difference plate R2 and the air layer A.

[0088] The reflected light to be noted here is the light reflected at the interface B11 and the interface B12 among the light reflected by the reflective polarizing plate RP. The light reflected toward the reflective polarizing plate RP at the interface B11 and the interface B12 is converted into the second linear polarized light LP2 when passing through the second phase difference plate R2. Therefore, the reflected light of a part of the optical path different from the optical path shown by the solid line passes through the reflective polarizing plate RP and reaches the pupil E as stray light, resulting in a decrease in display quality.

[0089] Moreover, in the comparative example shown here, the second polarizing plate P2 and the first phase difference plate R1 are stacked, and the second phase difference plate R2 and the reflective polarizing plate RP are stacked. Therefore, in the case where the first axis angle θ1 and the second axis angle θ2 do not match, the first axis angle θ1 and the second axis angle θ2 cannot be adjusted, which may further reduce the display quality.

[0090] Compared with such a comparative example, the present embodiment has the advantage that stray light can be suppressed and degradation of display quality can be suppressed.

[0091] Fig.10 It is shown Figure 1 FIG. 2 is a diagram showing another configuration example of a DSP of a display device shown in FIG.

[0092] Fig.10 The configuration example shown is Figure 2 Compared with the configuration example shown in the figure, the difference is that the first phase difference plate R1, the second phase difference plate R2 and the reflective polarizer RP are respectively covered with an anti-reflection layer AR. In the example shown in the figure, further, the first surface S1 of the first transparent support BS1 and the fourth surface S4 of the second transparent support BS2 are also respectively covered with an anti-reflection layer AR.

[0093] according to Fig.10 In the configuration example shown, undesired reflection is suppressed at the interface between the first phase difference plate R1 and the air layer, the interface between the first surface S1 and the air layer, the interface between the second phase difference plate R2 and the air layer, the interface between the reflective polarizing plate RP and the air layer, and the interface between the fourth surface S4 and the air layer. Thus, it is possible to suppress degradation of display quality.

[0094] Fig.11 It is shown Figure 1 FIG. 2 is a diagram showing another configuration example of a DSP of a display device shown in FIG.

[0095] Fig.11 The configuration example shown is Figure 2 Compared with the structure example shown, the difference is that the hologram optical element HE is replaced as an optical element having a lens function, and the side facing the second phase difference plate R2 is a semi-transmissive layer (half mirror) HM formed in a concave shape.

[0096] In the example shown in the figure, the first transparent support BS1 is formed as a plano-convex lens. That is, in the first transparent support BS1, the first surface S1 is formed as a convex surface, and the second surface S2 is formed as a plane parallel to the XY plane. The semi-transmissive layer HM is arranged on the first surface S1. The second phase difference plate R2 is arranged on the second surface S2.

[0097] The optical function of the display device DSP is briefly described below.

[0098] As shown by the dotted line, the display light DL emitted from the display element DE passes through the first phase difference plate R1, then passes through the semi-transparent layer HM, and then passes through the first transparent support BS1 and the second phase difference plate R2, and is reflected by the reflective polarizer RP through the air layer A. The display light DL reflected by the reflective polarizer RP passes through the second phase difference plate R2 and the first transparent support BS1 through the air layer A, and is reflected by the semi-transparent layer HM. The display light DL reflected by the semi-transparent layer HM passes through the first transparent support BS1 and the second phase difference plate R2, then passes through the air layer A, passes through the reflective polarizer RP, and then passes through the second transparent support BS2, and is focused on the pupil E of the user by the lens effect of the semi-transparent layer HM.

[0099] In such a configuration example, the same effects as those of the above-mentioned configuration example can be obtained.

[0100] Although not shown, Fig.10 The antireflection layer AR can be applied similarly to the illustrated configuration example.

[0101] Next, the inventors verified the influence of the mismatch between the first shaft angle θ1 and the second shaft angle θ2 through simulation.

[0102] Fig.12 It is a figure which shows the simulation result.

[0103] The simulation conditions are as follows: With the transmission axis T2 of the second polarizing plate P2 in the XY plane as a reference, the transmission axis T2 is set at an azimuth of 0°. The slow axis AX1 of the first phase difference plate R1 is set at an azimuth of 45°, and the first axis angle θ1 is set to 45°.

[0104] The slow axis AX2 of the second phase difference plate R2 is designed to have an azimuth of 135°, and the deviation from the designed value is represented by Δθr.

[0105] The transmission axis Trp of the reflective polarizing plate RP is designed to have an azimuth of 90°, and the amount of deviation from the designed value is represented by Δθp.

[0106] The retardation Δn·d of the first phase difference plate R1 and the second phase difference plate R2 is 144 nm. Δn is a parameter indicating the refractive index anisotropy or birefringence of each phase difference plate. d is equivalent to the thickness of each phase difference plate.

[0107] Fig.12 The horizontal axis is the deviation Δθr (°), and the vertical axis is the light leakage (au). Fig. 9 As described above, the undesired stray light caused by the mismatch between the second axis angle θ2 and the first axis angle θ1 corresponds to the light that reaches the pupil E after passing through the reflective polarizing plate RP.

[0108] The solid line in the figure represents the simulation result of the light leakage amount generated when the deviation amount Δθp is 0°. When the deviation amount Δθr is 0°, the second axis angle θ2 is equal to the first axis angle θ1, which is 45°. In this case, the light leakage amount is the lowest. It can be confirmed that as the absolute value of the deviation amount Δθr increases, the difference between the first axis angle θ1 and the second axis angle θ2 increases, and the light leakage amount increases.

[0109] The dotted line in the figure represents the simulation result of the light leakage amount generated when the deviation Δθp is 2°. When the deviation Δθr is 2°, the second axis angle θ2 is equal to the first axis angle θ1, which is 45°. In this case, the light leakage amount is the lowest. It can be confirmed that as the deviation Δθr increases or decreases from 2°, the difference between the first axis angle θ1 and the second axis angle θ2 increases, and the light leakage amount increases.

[0110] The dotted line in the figure represents the simulation result of the light leakage amount generated when the deviation amount Δθp is 5°. When the deviation amount Δθr is 5°, the second axis angle θ2 is equal to the first axis angle θ1, which is 45°. In this case, the light leakage amount is the lowest. It can be confirmed that as the deviation amount Δθr increases or decreases from 5°, the difference between the first axis angle θ1 and the second axis angle θ2 increases, and the light leakage amount increases.

[0111] As described above, according to this embodiment, a display device capable of suppressing a decrease in display quality can be provided.

[0112] It should be noted that several embodiments of the present invention have been described, but these embodiments are presented as examples and are not intended to limit the scope of the invention. These new embodiments can also be implemented in many other ways, and various omissions, substitutions, and changes can be made without departing from the scope of the invention. These embodiments and their variations are all included in the scope or purpose of the invention, and are also included in the invention described in the claims and their equivalents.

Claims

1. A display device comprising: Display components; A first phase difference plate, overlapping the display element; an optical element, overlapping the display element and the first phase difference plate, and having a lens function; A second phase difference plate, overlapping with the optical element and having a first main surface; as well as The reflective polarizing plate overlaps with the second phase difference plate and has a second main surface. The second main surface is not in direct contact with the first main surface but is rotatable relative to the first main surface.

2. The display device according to claim 1, wherein: The first phase difference plate and the second phase difference plate are 1 / 4 wavelength plates, The reflective polarizing plate is configured to reflect a first linearly polarized light and transmit a second linearly polarized light different from the first linearly polarized light.

3. The display device according to claim 1, wherein: The display element includes: a lighting device; a liquid crystal panel disposed between the lighting device and the first phase difference plate; a first polarizing plate disposed between the lighting device and the liquid crystal panel; and a second polarizing plate disposed between the liquid crystal panel and the first phase difference plate.

4. The display device according to claim 1, wherein: The optical element is a holographic optical element configured to reflect light reflected by the reflective polarizing plate toward the reflective polarizing plate.

5. The display device according to claim 1, wherein: The optical element is a semi-transmissive layer formed in a concave shape on a side facing the second phase difference plate, and is configured to reflect light reflected by the reflective polarizing plate toward the reflective polarizing plate.

6. The display device according to claim 1, wherein: The display device further comprises: a first transparent support body on which the optical element and the second phase difference plate are arranged; and The second transparent support is provided with the reflective polarizing plate.

7. The display device according to claim 1, wherein: The first phase difference plate, the second phase difference plate, and the reflective polarizing plate are respectively covered with an anti-reflection layer.

8. The display device according to claim 6, wherein: The display device further includes an adjustment mechanism that adjusts a rotation angle of the first transparent support or the second transparent support.

9. The display device according to claim 8, wherein: The first transparent support or the second transparent support is formed in a circular shape, The adjustment mechanism is configured to rotate the reflective polarizing plate with the center of the first transparent support or the second transparent support as a rotation axis.

10. The display device according to claim 8, wherein: The adjustment mechanism is configured to rotate the reflective polarizing plate about a fixed point in contact with an outer edge of the first transparent support or the second transparent support as a rotation axis.

11. The display device according to claim 8, wherein: The first transparent support or the second transparent support is formed in a circular shape, The adjustment mechanism is configured to rotate the second transparent support body with the center of the first transparent support body or the second transparent support body as a rotation axis.

12. The display device according to claim 8, wherein: The adjustment mechanism is configured to rotate the second transparent support body about a fixed point in contact with an outer edge of the first transparent support body or the second transparent support body as a rotation axis.

13. The display device according to claim 1, wherein: The display element is configured to emit linearly polarized display light.

14. The display device according to claim 1, wherein: The reflective polarizing plate is entirely rotatable relative to the first main surface.

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