Display device

Abstract

The invention relates to a display device. According to one embodiment, a display device includes: a display element including a display unit that displays an image; a first phase difference plate overlapping the display element; a holographic optical element which is adjacent to the display element and does not overlap the display unit; a second phase difference plate having a first surface facing the first phase difference plate and the holographic optical element, and a second surface on the opposite side of the first surface, the first surface being neither in direct contact with the main surface of the first phase difference plate nor in direct contact with the main surface of the holographic optical element; and a reflective polarizing plate disposed on the second surface.

Description

[0001] Related Applications

[0002] This application claims the priority based on Japanese Patent Application No. 2023-097097 for which it applied on June 13, 2023, and cites all the contents described in the Japanese 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 so that images are displayed on a display set 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] As an example of a technology for realizing such a head mounted display, there is known a technology for guiding light from a display element to the pupil of a user using a holographic optical element. Summary of the invention

[0006] An object of the embodiment is to provide a display device that can be reduced in size.

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

[0008] A display element having a display portion for displaying an image; a first phase difference plate overlapping the display element; a holographic optical element adjacent to the display element and not overlapping the display portion; a second phase difference plate having a first surface and a second surface opposite to the first surface, the first surface facing the first phase difference plate and the holographic optical element and not in direct contact with a main surface of the first phase difference plate or a main surface of the holographic optical element; and a reflective polarizing plate arranged on the second surface.

[0009] According to one embodiment, a display device includes:

[0010] A display element having a display portion for displaying an image; a holographic optical element adjacent to the display element and not overlapping the display portion; a transparent substrate having a first principal surface facing the display element and the holographic optical element and a second principal surface on the opposite side of the first principal surface; and a transparent adhesive layer for bonding the display element and the holographic optical element to the first principal surface, respectively.

[0011] According to the embodiment, a display device that can be reduced in size can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] 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.

[0013] Figure 2 It is shown Figure 1 A diagram showing an example of the configuration of a display device DSP.

[0014] 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.

[0015] Figure 4 It is used to illustrate Figure 2 A diagram showing the optical effects of the display device DSP is shown.

[0016] Figure 5 It is shown Figure 1 FIG. 2 is a diagram showing another configuration example of a DSP of a display device shown in FIG.

[0017] Figure 6 It is shown Figure 1 FIG. 2 is a diagram showing another configuration example of a DSP of a display device shown in FIG.

[0018] Figure 7 It is shown Figure 1 FIG. 2 is a diagram showing another configuration example of a DSP of a display device shown in FIG.

[0019] Figure 8 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. 9 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.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.

[0022] Fig.11 It is shown that it can be applied to Fig.10 The diagram shows an example of the configuration of a display element DE of a display device DSP shown.

[0023] Fig.12 It is used to illustrate Fig.10 A diagram showing the optical effects of the display device DSP is shown.

[0024] Fig.13 It is shown Figure 1 FIG. 2 is a diagram showing another configuration example of a DSP of a display device shown in FIG.

[0025] Fig.14 It is shown Figure 1 FIG. 2 is a diagram showing another configuration example of a DSP of a display device shown in FIG.

[0026] Fig.15 This is a diagram for explaining an example of a method for manufacturing a hologram optical element HE.

[0027] Fig.16 It is a diagram for explaining another example of the method for manufacturing the hologram optical element HE. DETAILED DESCRIPTION

[0028] 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.

[0029] 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 called the first direction X, the direction along the Y-axis is called the second direction Y, and the direction along the Z-axis is called 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 called the XY plane, and observing the XY plane is called top view.

[0030] 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.

[0031] The glasses 1, for example, include a display device DSPR for the right eye and a display device DSPL for the left eye. The display devices DSPR and DSPL each include a display element DE and a holographic optical element HE. The display element DE and the holographic optical element HE are arranged in a first direction X. The display devices DSPR and DSPL are arranged in a second direction Y. It should be noted that the display element DE and the holographic optical element HE may be arranged in the second direction Y, or in a direction different from the first direction X and the second direction Y.

[0032] The display devices DSPR and DSPL have substantially the same configuration and will be described below simply as the display device DSP.

[0033] Figure 2 It is shown Figure 1A diagram showing an example of the configuration of a display device DSP.

[0034] 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 into a flat plate along the XY plane. The normal line Nhe of the holographic optical element HE, the normal line Nrp of the reflective polarizing plate RP, and the normal line Nde of the display element DE are parallel to each other and are all parallel to the third direction Z.

[0035] 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.

[0036] 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 self-luminous light-emitting elements such as organic electroluminescent (EL) elements, micro LEDs, and mini LEDs. When the display element DE is a display panel having light-emitting elements, the lighting device and the first polarizing plate are omitted.

[0037] 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. 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. Although not described in detail, 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°.

[0038] In this specification, the state of "overlapping" of two components is defined as a state in which a part of another component exists on the normal line of one component. In addition, the state of "overlapping" includes a state in which the two components are in contact with each other, a state in which the two components are bonded to each other, and a state in which a space or another component exists between the two components.

[0039] The holographic optical element HE is arranged so as not to overlap with the display element DE in the third direction Z but to be adjacent to the display element DE in the first direction X. The holographic optical element HE is supported by a support body BS1. The holographic optical element HE is a resin film having a pattern of interference fringes recorded thereon, and has a lens function of diffracting incident light of a specific wavelength in a predetermined direction and focusing the incident light.

[0040] The second phase difference plate R2 is configured to be opposite to the first phase difference plate R1 and the holographic optical element HE through the air layer A in the third direction Z. The second phase difference plate R2 has a first surface R2a and a second surface R2b on the opposite side of the first surface R2a. The first surface R2a and the second surface R2b are opposite in the third direction Z. The first surface R2a is equivalent to the surface facing the first phase difference plate R1 and 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. Although not described in detail, the slow axis of the second phase difference plate R2 intersects with 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.

[0041] The reflective polarizing plate RP is arranged on the second surface R2b of the second phase difference plate R2. In addition, in the illustrated example, the stack of the reflective polarizing plate RP and the second phase difference plate R2 is supported by a transparent support body BS2. As the reflective polarizing plate RP, a multilayer thin film type polarizing plate, a wire grid type polarizing plate, etc. can be applied. Such a reflective polarizing plate RP is configured to reflect the first linear polarized light and allow the second linear polarized light different from the first linear polarized light to pass through. 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.

[0042] The optical function of the display device DSP is briefly described below.

[0043] 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 second phase difference plate R2 via the air layer A, and is reflected by the reflective polarizer RP. The display light DL reflected by the reflective polarizer RP is reflected by the holographic optical element HE via the air layer A. The display light DL reflected by the holographic optical element HE passes through the second phase difference plate R2 via the air layer A again, then passes through the reflective polarizer RP, and is focused on the pupil E of the user by the lens action of the holographic optical element HE.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] The display portion DA is a region configured to display an image on the liquid crystal panel PNL. The normal line Nde of the display element DE corresponds to, for example, the normal line of the first substrate SUB1 or the second substrate SUB2.

[0048] The lighting device IL includes a light guide plate LG and a light source LS. The light guide plate LG faces the first polarizing plate P1 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. The light source LS is arranged on the side opposite to the holographic optical element HE sandwiching the light guide plate LG in the first direction X. The liquid crystal panel PNL is located between the light source LS and the holographic optical element HE in the first direction X.

[0049] 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.

[0050] 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 to form illumination light. The illumination light incident on the liquid crystal panel PNL is inclined relative to the normal line Nde. The liquid crystal panel PNL selectively modulates the illumination light in the display unit DA. Then, a part of the illumination light passes through the second polarizing plate P2 to form linearly polarized display light DL.

[0051] Figure 4 It is used to illustrate Figure 2 A diagram showing the optical effects of the display device DSP is shown.

[0052] First, the display light DL of the first linear polarized light LP1 transmitted through the second polarizing plate P2 of the display element DE is converted into the first circular polarized light CP1 through the first phase difference plate R1. The first circular polarized light CP1 transmitted through the first phase difference plate R1 is converted into the first linear polarized light LP1 through the second phase difference plate R2.

[0053] 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.

[0054] The second circularly polarized light CP2 passing through the second phase difference plate R2 is reflected and diffracted by the hologram optical element HE. The second circularly polarized light CP2 reflected by the hologram optical element HE passes through the second phase difference plate R2 and is converted into the second linearly polarized light LP2. The second linearly polarized light LP2 is a linearly polarized light having a polarization axis orthogonal to the first linearly polarized light LP1.

[0055] The second linearly polarized light LP2 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.

[0056] 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 .

[0057] 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.

[0058] In addition, the display element DE and the hologram optical element HE do not overlap in the third direction Z, but are arranged in the first direction X. That is, there is no hologram optical element HE between the display element DE and the reflective polarizing plate RP in the third direction Z. Therefore, in the optical path of the display light DL from the display element DE to the reflective polarizing plate RP, the display light DL is not reflected by the hologram optical element HE. Therefore, in the hologram optical element HE, if it is assumed that almost all of the reflected light from the reflective polarizing plate RP is reflected, almost 100% of the display light DL emitted from the display element DE can be focused on the pupil E, and the light utilization efficiency can be improved.

[0059] Figure 5 It is shown Figure 1 FIG. 2 is a diagram showing another configuration example of a DSP of a display device shown in FIG.

[0060] Figure 5 The configuration example shown is Figure 2 Compared with the configuration example shown in the figure, the difference is that a light shielding body LSM is arranged on the back side of the hologram optical element HE. In the example shown in the figure, the light shielding body LSM overlaps with the support body BS1 in the third direction Z. The hologram optical element HE is located between the second phase difference plate R2 and the light shielding body LSM in the third direction Z.

[0061] The light shielding body LSM may be a film bonded to the support body BS1 or a plate that can be attached to and detached from the glasses. In addition, the light shielding body LSM may be a liquid crystal element or the like configured to be able to change the transmittance of external light.

[0062] Glasses including the display device DSP of such a configuration example can be used, for example, to provide virtual reality.

[0063] Figure 6 It is shown Figure 1 FIG. 2 is a diagram showing another configuration example of a DSP of a display device shown in FIG.

[0064] Figure 6 The configuration example shown is Figure 2 The difference from the configuration example shown is that the hologram optical element HE is configured to transmit the external light AL. The user can visually recognize the image displayed on the display element DE while visually recognizing the surrounding environment of the display device DSP.

[0065] Glasses including the display device DSP of such a configuration example can be used, for example, to provide augmented reality.

[0066] Figure 7 It is shown Figure 1 FIG. 2 is a diagram showing another configuration example of a DSP of a display device shown in FIG.

[0067] Figure 7 The configuration example shown is Figure 2 Compared with the illustrated configuration example, the difference is that the first phase difference plate R1, the second phase difference plate R2 and the hologram optical element HE are respectively covered with an anti-reflection layer AR.

[0068] In the absence of the anti-reflection layer AR, there is a concern that undesired reflected light may be generated at the interface between the first phase difference plate R1 and the air layer, the interface between the second phase difference plate R2 and the air layer, and the interface between the holographic optical element HE and the air layer. Such undesired reflected light may reach the user's pupil E through an optical path different from the normal optical path of the display light DL, which may cause a decrease in display quality.

[0069] according to Figure 7In the configuration example shown, reflection at the interface between the first phase difference plate R1 and the air layer, reflection at the interface between the second phase difference plate R2 and the air layer, and reflection at the interface between the hologram optical element HE and the air layer are suppressed. Therefore, it is possible to suppress degradation of display quality.

[0070] Figure 8 It is shown Figure 1 FIG. 2 is a diagram showing another configuration example of a DSP of a display device shown in FIG.

[0071] Figure 8 The configuration example shown is Figure 2 Compared with the configuration example shown in FIG. 1 , the display light DL is parallel light. In such a configuration example, in the first direction in which the display element DE and the hologram optical element HE are arranged, the width Wda of the display portion DA is equal to the width Whe of the hologram optical element HE.

[0072] When the display light DL is divergent light, the width Whe needs to be set larger than the width Wda. Figure 8 In the configuration example shown, Figure 2 Compared with the configuration example shown, the width Whe of the hologram optical element HE can be reduced, and the display device DSP can be further miniaturized. In addition, since the emission angle of the display light DL is constant, the optical design becomes easy.

[0073] Although not shown, Figure 7 The antireflection layer AR can be applied similarly to the illustrated configuration example.

[0074] Fig. 9 It is shown Figure 1 FIG. 2 is a diagram showing another configuration example of a DSP of a display device shown in FIG.

[0075] Fig. 9 The configuration example shown is Figure 2 Compared with the configuration example shown in FIG. 1 , the difference is that the normal line Nde of the display element DE is inclined relative to the normal line Nrp of the reflective polarizing plate RP. The display element DE has an end DEa close to the holographic optical element HE and an end DEb on the opposite side of the end DEa. The display element DE is inclined in such a way that the end DEb is closer to the reflective polarizing plate RP than the end DEa. It should be noted that the normal line Nhe of the holographic optical element HE is parallel to the normal line Nrp.

[0076] The display light DL emitted along the normal line Nde of the display element DE may be divergent light or parallel light. It should be noted that the display element DE is configured to display an image taking distortion into consideration so that a normal image is focused on the pupil E.

[0077] According to such a configuration example, the width along the first direction X can be reduced, and further miniaturization of the display device DSP is possible. Figure 2 Compared with the configuration examples shown in the above description, the slope of the emission angle of the display light DL is small, the optical design becomes easy, and the existing lighting device IL for emitting display light in the front direction can be applied.

[0078] Although not shown, Figure 7 The antireflection layer AR can be applied similarly to the illustrated configuration example.

[0079] 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.

[0080] The display device DSP includes a display element DE, a hologram optical element HE, a transparent substrate SB, and a transparent adhesive layer AD. The display element DE, the hologram optical element HE, and the transparent substrate SB are all formed in a flat plate shape along the XY plane.

[0081] Display element DE and Figure 2 The illustrated configuration example also includes the lighting device IL, the liquid crystal panel PNL, the first polarizing plate P1, and the second polarizing plate P2. When the display element DE is a display panel including a light-emitting element, the lighting device and the first polarizing plate are omitted.

[0082] The hologram optical element HE is arranged not to overlap with the display element DE in the third direction Z but to be adjacent to the display element DE in the first direction X. The hologram optical element HE is supported by a support body BS1. The hologram optical element HE has a lens function of diffracting incident light of a specific wavelength in a predetermined direction and focusing the incident light.

[0083] The transparent substrate SB is arranged to face the display element DE and the holographic optical element HE in the third direction Z. The liquid crystal panel PNL is arranged in the third direction Z between the illumination device IL and the transparent substrate SB.

[0084] The transparent substrate SB has a first main surface SBa and a second main surface SBb on the opposite side of the first main surface SBa. The first main surface SBa and the second main surface SBb are opposite in the third direction Z. The first main surface SBa is equivalent to the surface facing the display element DE and the holographic optical element HE. The second main surface SBb is in contact with a low refractive index layer having a lower refractive index than the transparent substrate SB. In the example shown in the figure, the low refractive index layer is air. Such a transparent substrate SB is a glass substrate or a resin substrate.

[0085] The transparent adhesive layer AD bonds the display element DE and the hologram optical element HE to the first main surface SBa, respectively. From the viewpoint of suppressing the generation of an undesired reflection interface, it is desirable that the refractive index of the transparent adhesive layer AD is equal to that of the transparent substrate SB.

[0086] The optical function of the display device DSP is briefly described below.

[0087] As shown by the dotted line, the display light DL emitted from the display element DE passes through the transparent adhesive layer AD and then enters the transparent substrate SB. The display light DL entering the transparent substrate SB is totally reflected on the second main surface SBb. In other words, the display element DE is configured to emit the display light DL at an angle that is totally reflected by the second main surface SBb. The display light DL reflected by the transparent substrate SB passes through the transparent adhesive layer AD and then is reflected by the holographic optical element HE. The display light DL reflected by the holographic optical element HE passes through the transparent adhesive layer AD again and the transparent substrate SB, and is focused on the pupil E of the user by the lens action of the holographic optical element HE.

[0088] Fig.11 It is shown that it can be applied to Fig.10 The diagram shows an example of the configuration of a display element DE of a display device DSP shown.

[0089] 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.

[0090] LCD panel PNL and Figure 3 The illustrated configuration example is also of a transmissive type and includes a first substrate SUB1, a second substrate SUB2, and a liquid crystal layer LC.

[0091] 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. The light source LS is arranged on the side opposite to the holographic optical element HE sandwiching the light guide plate LG in the first direction X. The liquid crystal panel PNL is located between the light source LS and the holographic optical element HE in the first direction X.

[0092] 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 to form illumination light. When the illumination light passes through the prism sheet PS, it is refracted to an angle that is totally reflected by the second main surface SBb as described above. The illumination light that passes through the prism sheet PS enters the liquid crystal panel PNL. The liquid crystal panel PNL selectively modulates the illumination light in the display unit DA. Then, a part of the illumination light passes through the second polarizing plate P2 to form display light DL of linearly polarized light.

[0093] Fig.12 It is used to illustrate Fig.10 A diagram showing the optical effects of the display device DSP is shown.

[0094] First, the display light DL of the first linear polarized light LP1 transmitted through the second polarizing plate P2 of the display element DE enters the transparent substrate SB and is totally reflected by the second main surface SBb. The display light DL totally reflected by the second main surface SBb is reflected and diffracted by the holographic optical element HE. The display light DL reflected by the holographic optical element HE transmits through the transparent substrate SB and is focused on the pupil E of the user by the lens action of the holographic optical element HE.

[0095] It should be noted that the reference Fig.12 The first linear polarized light LP1 described above is replaced by the second linear polarized light LP2. In addition, the polarization state of the display light DL after passing through the second polarizing plate P2 does not need to be maintained as linear polarized light.

[0096] According to this configuration example, Figure 2 The same effects as those of the configuration examples shown are achieved.

[0097] In addition, optical parts such as a phase difference plate and a reflective polarizing plate are not required, so that weight reduction and cost reduction can be achieved.

[0098] In addition, Figure 2 Compared with the illustrated configuration example, the thickness along the third direction Z can be further reduced.

[0099] Furthermore, since there are no interfaces between the display element DE and the air layer and no interfaces between the hologram optical element HE and the air layer, it is possible to suppress undesired reflection of the display light DL on the optical path.

[0100] Fig.13 It is shown Figure 1 FIG. 2 is a diagram showing another configuration example of a DSP of a display device shown in FIG.

[0101] Fig.13 The configuration example shown is Fig.10 Compared with the illustrated configuration example, the difference is that a light shielding body LSM is arranged on the back side of the hologram optical element HE.

[0102] Regarding the structure of the light shielding body LSM, refer to Figure 5 The configuration examples described are the same.

[0103] Glasses including the display device DSP of such a configuration example can be used, for example, to provide virtual reality.

[0104] Fig.14 It is shown Figure 1 FIG. 2 is a diagram showing another configuration example of a DSP of a display device shown in FIG.

[0105] Fig.14 The configuration example shown is Fig.10 The difference from the configuration example shown is that the hologram optical element HE is configured to transmit the external light AL. The user can visually recognize the image displayed on the display element DE while visually recognizing the surrounding environment of the display device DSP.

[0106] Glasses including the display device DSP of such a configuration example can be used, for example, to provide augmented reality.

[0107] Hereinafter, a method for manufacturing the hologram optical element HE will be briefly described.

[0108] Fig.15 This is a diagram for explaining an example of a method for manufacturing a hologram optical element HE.

[0109] The photosensitive resin PP is formed on one surface of the transparent support BS. Figure 2 The support body BS1 shown in the figure may be the same as the support body BS1, or may be different from the support body BS1.

[0110] The object light Ob is parallel light, and is irradiated toward the photosensitive resin PP via the lens L1. At this time, the object light Ob is irradiated from a direction along the normal line Nbs of the support body BS.

[0111] The reference light Rf is parallel light and is irradiated toward the photosensitive resin PP via the lens L2. At this time, the reference light Rf is irradiated from a direction inclined relative to the normal line Nbs of the support body BS. The reference light Rf and the object light Ob are lights of the same wavelength and interfere at the position of the photosensitive resin PP.

[0112] Interference fringes between the reference light Rf and the object light Ob are recorded in the photosensitive resin PP. Thus, a hologram optical element HE having a lens effect equivalent to that of a concave mirror for incident light (divergent light) from a direction inclined relative to the normal line Nbs is manufactured. The hologram optical element HE manufactured in this way can be used, for example, as Figure 2 The holographic optical element HE of the display device DSP shown in FIG.

[0113] Fig.16 It is a diagram for explaining another example of the method for manufacturing the hologram optical element HE.

[0114] Fig.16 The manufacturing method shown is Fig.15 The difference from the manufacturing method shown is that the reference light Rf is parallel light and is irradiated toward the photosensitive resin PP without passing through a lens. The reference light Rf and the object light Ob are lights of the same wavelength and interfere at the position of the photosensitive resin PP.

[0115] Interference fringes between the reference light Rf and the object light Ob are recorded in the photosensitive resin PP. Thus, a hologram optical element HE having a lens effect equivalent to that of a concave mirror for incident light (parallel light) from a direction inclined relative to the normal line Nbs is manufactured. The hologram optical element HE manufactured in this way can be used, for example, as Figure 8 The holographic optical element HE of the display device DSP is shown.

[0116] As described above, according to this embodiment, a display device that can be reduced in size can be provided.

[0117] 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: A display element having a display portion for displaying an image; A first phase difference plate, overlapping the display element; a holographic optical element, adjacent to the display element and not overlapping the display portion; a second phase difference plate having a first surface and a second surface opposite to the first surface, wherein the first surface faces the first phase difference plate and the holographic optical element and is not in direct contact with a main surface of the first phase difference plate or a main surface of the holographic optical element; as well as The reflective polarizing plate is disposed on the second surface.

2. The display device according to claim 1, wherein: The display element is configured to emit linearly polarized display light, 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 hologram optical element has a lens function and is configured to reflect the light reflected by the reflective polarizing plate toward the reflective polarizing plate.

4. The display device according to claim 3, wherein: The display device further includes a light shielding body disposed on a rear surface side of the hologram optical element.

5. The display device according to claim 3, wherein: The holographic optical element is configured to transmit external light.

6. 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.

7. The display device according to claim 6, wherein: The lighting device includes a light guide plate and a light source facing a side surface of the light guide plate. In the direction in which the display element and the holographic optical element are arranged, the liquid crystal panel is located between the light source and the holographic optical element.

8. The display device according to claim 1, wherein: The first phase difference plate, the second phase difference plate, and the holographic optical element are respectively covered with an anti-reflection layer.

9. The display device according to claim 1, wherein: In the direction in which the display element and the holographic optical element are arranged, the width of the display portion is equal to the width of the holographic optical element.

10. The display device according to claim 1, wherein: The normal line of the holographic optical element is parallel to the normal line of the reflective polarizing plate, A normal line of the display element is inclined with respect to a normal line of the reflective polarizing plate.

11. The display device according to claim 1, wherein: The first surface faces the first phase difference plate and the holographic optical element via an air layer.

12. A display device comprising: A display element having a display portion for displaying an image; a holographic optical element adjacent to the display element and not overlapping the display portion; A transparent substrate having a first main surface facing the display element and the holographic optical element and a second main surface on the opposite side of the first main surface; as well as The transparent adhesive layer adheres the display element and the holographic optical element to the first main surface respectively.

13. The display device according to claim 12, wherein: The display element is configured to emit display light that is totally reflected by the second main surface.

14. The display device according to claim 12, wherein: The holographic optical element has a lens function and is configured to reflect the light reflected by the second main surface toward the transparent substrate.

15. The display device according to claim 14, wherein: The display device further includes a light shielding body disposed on a rear surface side of the hologram optical element.

16. The display device according to claim 14, wherein: The holographic optical element is configured to transmit external light.

17. The display device according to claim 12, wherein: The display element includes: a lighting device; a liquid crystal panel disposed between the lighting device and the transparent substrate; and a prism sheet disposed between the lighting device and the liquid crystal panel.

18. The display device according to claim 17, wherein: The lighting device includes a light guide plate and a light source facing a side surface of the light guide plate. In the direction in which the display element and the holographic optical element are arranged, the liquid crystal panel is located between the light source and the holographic optical element.

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