JP2002221621A - Polarization selective hologram optical element, image display element and image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain good polarization separation characteristics not only when the incident angle of an incident beam is small but when the incident angle increases. SOLUTION: The refractive index modulation type polarization selective hologram element has such a structure that optically anisotropic regions 5 and anisotropic regions 6 are alternately deposited. The optical axis of the anisotropic region 6 is aligned almost parallel to the entrance face for the reproducing light and almost parallel to the interface between the isotropic regions 5 and the anisotropic regions 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polarization selective hologram optical element, an image display element and an image display apparatus applied to an image display apparatus using a reflection type spatial light modulator, and more particularly to a projection type image display apparatus. In addition, the present invention relates to enabling weight reduction, cost reduction, high contrast, and high efficiency in a virtual image display device.

[0002]

2. Description of the Related Art As described below, various image display devices and an image display device constituted by using these image display devices have been proposed.

[1] Transmission-type polarization-selective hologram optical element configured to have two isotropic regions Conventionally, transmission-type polarization-selective hologram optics that divides incident light according to the polarization component of the incident light. As an element, Japanese Patent Application Laid-Open
As described in Japanese Patent Application Laid-Open No. 189809/1989, there is a color filter technology formed of a normal thick hologram. This is based on the incident polarization dependence of the diffraction efficiency of a thick hologram composed of isotropic material, and is theoretically proved by solving the exact solution of "coupled-wavetheory" ( Reference: MG Moha
ram and T. K. Gayload: Rigourous coupled-wave anal
ysis of planar grationgdiffraction, J. 0pt. Soc. A
m. 71, 811-818 (1977); G. Moharam and T. K. Ga
yload: Rigourous coupled-wave analysis of grationg
diffractlon E-mode polarization and lossws, J. 0p
t. Soc. Am. 73, 451-455 (1983)).

For example, in the case of a reflective hologram,
Hologram thickness t and pitch of interference fringes in the hologram Λ
When the value t / Λ determined by
As shown in (1), there is a difference in the diffraction efficiency between TE (S-polarized light) and TM (P-polarized light), and the S-polarized light has a maximum diffraction efficiency of about 45% higher than the P-polarized light.

An image display device has been proposed utilizing this phenomenon as shown in FIG. In this image display device, when the reading light is obliquely incident on the hologram color filters 101r, 101g, and 101b arranged in a laminated manner via the coupling prism 102, the S-polarized component of the reading light is The light is mainly diffracted and is incident on the liquid crystal layer 103 almost vertically as illumination light.
This illumination light passes through the liquid crystal layer 103 and passes through the dielectric mirror film 1.
04. Thus, the dielectric mirror film 10
Of the illumination light reflected by 4, the light reflected by the liquid crystal layer 103 with the polarization direction modulated by 90 ° (P-polarized component) has a low diffraction effect due to the above-described phenomenon.
Hologram color filters 101r, 101g, 10
At 1b, the light is emitted from the hologram color filters 101r, 101g, 101b almost vertically without undergoing any diffraction action. The illuminating light thus emitted enters a projection lens (not shown), and an image is formed on a screen by the projection lens.

[2] Transmission type polarization selective hologram optical element composed of anisotropic region and isotropic region In recent years, as shown in FIG. Holographically-formed polymer dispersed liquid crystal (holographically-formed polymer dispersed liq) that mixes and forms interference fringes by holographic techniques
uid crystals, hereinafter referred to as “H-PDLC”. ) Are also active (Reference papers: A. Ogiwara, Y. Kuratomi, T. Kar)
awa, A.Kakimoto and S.Mizuguchi, Proc.SID XXX, 1124 (1
999)).

[0007] This is a technique derived from the photo-induced phase separation "PDLC" discovered in the mid-1980s (Reference: Crawford GP and Zumer S., in Liquid Crystals i).
n Complex Geometries, Ulor and Francis, London (199
6)).

[0008] The "H-PDLC" will be described below.
A manufacturing method and an operation principle will be described. First, a material in which liquid crystal molecules, a monomer (prepolymer), a sensitizing dye, a reaction initiator, and the like are mixed is sandwiched between glass plates and sealed. This is exposed to interference fringes formed by laser light. Then, in the bright portion of the interference fringes, the monomer starts photopolymerization and polymerizes. For this reason, in the bright part and the dark part of the interference fringe, a monomer concentration distribution occurs,
Transfer of the monomer from the dark area to the light area occurs. as a result,
A periodic structure is formed by phase separation of a bright portion rich in polymer concentration and a dark portion rich in liquid crystal molecules. In the next step, the liquid crystal molecules are arranged so as to be orthogonal to the polymer phase.
The mechanism of this phenomenon has not yet been elucidated, but various related studies have been conducted (for example,
"CC Bowley, AK Fontecchio, and GP Crawfo
rd, Proc. SID XXX, 958 (1999) ").

After that, ultraviolet irradiation is performed to perform a fixing process. In the hologram optical element prepared as described above, the refractive index of the polymer layer and the ordinary ray refractive index of the liquid crystal layer are almost equal, and the refractive index of the polymer layer and the extraordinary ray refractive index of the liquid crystal layer are different. Functions as a selective hologram optical element.

[3] Transmission type polarization selective hologram optical element composed of two anisotropic regions Further, as described in JP-A-11-271536, as shown in FIGS. There is a technique for configuring a polarization-selective hologram element by configuring a photocurable liquid crystal and a non-polymerizable liquid crystal by controlling the orientation direction of the liquid crystal. The main advantage of this technique over the above-described laminated hologram in which an isotropic material and an anisotropic material are laminated is that, as shown in FIGS. 15 and 16, the orientation of the non-polymerizable liquid crystal is switched by applying an electric field. When controlling the presence or absence of diffraction by setting the ordinary refractive index and the extraordinary refractive index of the photocurable liquid crystal and the non-polymerizable liquid crystal to be equal to each other, diffraction can be performed regardless of the light incident angle and incident polarization direction. The point is that the diffraction efficiency in a state where no diffraction occurs can be suppressed to zero in principle.

This is because the photocurable liquid crystal and the non-polymerizable liquid crystal are oriented in the same direction when no diffraction occurs, so that there is no difference in the refractive index with respect to incident light rays from any direction. That's why.

[0012]

The problems to be solved by the present invention are as follows.

[1] In a thick hologram element composed of a normal isotropic material shown in FIG.
There is a problem that the polarization separation characteristics are low. This is because, in this hologram element, unlike the hologram element using an anisotropic material, the polarization component of either P or S
This is because an apparent interference fringe having a modulated refractive index always exists.

In this sense, it can be said that the hologram element is not a polarization-selective hologram element but a polarization-dependent hologram element. Usually, a photopolymerizable polymer such as a photopolymer is used as a material of such a hologram element. However, in the case of this material, it is difficult to set the refractive index modulation Δn to 0.05 or more. The refractive index modulation degree is an important parameter for determining the diffraction efficiency of the hologram. Generally, the larger the value, the easier it is to secure a large diffraction efficiency.

[2] Also, as shown in FIG. 14, the "H-PDLC" having no clear alignment control means has the following two problems.

First, the first problem is that it is difficult to increase the order parameter (order parameter) of the liquid crystal alignment. This is partly due to the fact that the mechanism of alignment, in which the liquid crystal molecules are arranged so as to be orthogonal to the polymer layer, has not been elucidated at the present time. To obtain a higher degree of order, for example, use of an alignment film In this case, it is necessary to take an orienting means with a clear mechanism. In addition,
As the degree of order increases, the diffraction efficiency of polarized light having a certain polarization direction increases, and the diffraction efficiency of polarized light having a polarization direction orthogonal to the polarization direction decreases, so that PS polarization separation characteristics are improved.

The second problem is that, as shown in FIG.
The isotropic region (region 1) and the optical axis are oriented substantially parallel to the light receiving surface of the polarization selective hologram optical element and substantially perpendicular to the boundary surface between the isotropic region and the anisotropic region. In the “H-PDLC” in which the anisotropic region (region 2) is stacked, when the incident angle of light on the polarization selective hologram element deviates from the optimal angle, the apparent refractive index modulation degree (Δn) And the diffraction efficiency decreases. That is, in the "H-PDLC" shown in FIG. 17, when the incident angle of the light beam becomes large, the apparent refraction of the refractive index anisotropic region including the liquid crystal with respect to polarized light (P-polarized light in this case) that causes a diffraction phenomenon. The rate n2 gradually decreases from ne. On the other hand, since the refractive index n1 of the isotropic refractive index region is invariable, the refractive index modulation Δn = | n1-
n2 | becomes small.

For example, assuming that the refractive index n1 of the region 1 is 1.5, the refractive index n of the region 2 in the direction orthogonal to the optical axis is
o = 1.5, refractive index ne = 1.65 in the direction along the optical axis
When calculating the refractive index of each region when the light enters the liquid crystal layer at an incident angle θmed = 40 °, the refractive index np1 of P-polarized light in the region 1 is shown as follows.

NP1 = no = 1.5 The refractive index np2 of the P-polarized light in the region 2 is shown as follows.

NP2 = (cos2 [50] / no2 + sin2
[50] / ne2) = 1.583 From these results, Δn, which is the difference between these refractive indices, is:
0.083.

[3] As shown in FIGS. 15 and 16, in a polarization-selective hologram optical element in which a photo-curable liquid crystal and a non-polymerizable liquid crystal are laminated and the orientation direction of the non-polymerizable liquid crystal is controllable. As shown in FIG. 18, the optical axis was oriented substantially parallel to the light receiving surface of the polarization selective hologram optical element and oriented substantially perpendicular to the boundary between the isotropic region and the anisotropic region. “H−” is obtained by laminating an anisotropic region (region 1) and an anisotropic region (region 2) whose optical axis is oriented substantially perpendicular to the light receiving surface of the polarization selective hologram optical element.
In the “PDLC”, as the incident angle of light increases, the apparent refractive index n1 of the region 1 with respect to polarized light that causes diffraction (P-polarized light in this case) gradually decreases from ne. On the other hand, since the apparent refractive index n2 of the region 2 gradually increases from no, the refractive index modulation degree Δn = |
n1-n2 | is further reduced as compared with the polarization selective hologram optical element shown in FIG. This means that when the angle of incidence of the light beam on the polarization-selective hologram optical element is increased, the diffraction efficiency of the incident light beam is hardly ensured.

Actually, as shown in FIG. 19, when the optical axes of regions 1 and 2 are indicated by refractive index ellipsoids orthogonal to each other, the refractive index no = 1.5 in the direction orthogonal to the optical axis. , The refractive index ne = 1 in the direction along the optical axis.
When the refractive index of each region is calculated when the incident angle θmed on the liquid crystal layer is θmed = 40 °, the region 1
Is represented as follows.

NP1 = (cos2 [40] / no2 + sin2
[40] / ne2) = 1.557 The refractive index np2 of the P-polarized light in the region 2 is expressed as follows.

NP2 = (cos2 [50] / no2 + sin2
[50] / ne2) = 1.583 From these results, it can be seen that the difference Δn between these refractive indices is only 0.026. This value is shown in FIG.
This value is smaller than that of the polarization selective hologram optical element shown in FIG.

As shown in FIG. 20, each layer constituting the polarization-selective hologram optical element has an optical axis substantially parallel to the light-receiving surface of the polarization-selective hologram optical element and an isotropic region. An anisotropic region (region 1) oriented substantially parallel to the boundary surface with the anisotropic region, and an optical axis oriented substantially perpendicular to the light receiving surface of the polarization selective hologram optical element. A configuration in which an anisotropic region (region 2) is laminated, as shown in FIG. 21, the optical axis is substantially parallel to the light receiving surface of this polarization selective hologram optical element, and the isotropic region and the anisotropic region An anisotropic region (region 1) oriented substantially perpendicular to the boundary surface with the region, and an anisotropic region whose optical axis is substantially parallel to the light receiving surface of the polarization selective hologram optical element and isotropic. Region (region 2) which is oriented substantially parallel to the interface with the anisotropic region. Structure formed by laminating the door, and, FIG. 22
As shown in (1), an isotropic region (region 1) and an anisotropic region (region 2) whose optical axis is oriented substantially perpendicular to the light receiving surface of the polarization selective hologram optical element were laminated. Configurations are possible.

Regions 1 and 2 shown in FIGS. 20 and 21
In the case where both of the two regions are configured as anisotropic regions, the light is diffracted for both P and S incident polarized light, so that the polarization selectivity is low. In the one configured by the isotropic region and the anisotropic region shown in FIG.
When the incident angle is small, there is a problem that the refractive index modulation Δn becomes small.

Therefore, the present invention has been proposed in view of the above-mentioned situation, and is not limited to the case where the incident angle of the incident light beam is small, but also the case where the incident angle is large.
An object of the present invention is to provide a polarization selective hologram optical element capable of obtaining good polarization separation characteristics, and to provide an image display device and an image display device using the polarization selective hologram optical element.

[0028]

In order to solve the above-mentioned problems, a polarization-selective hologram optical element according to the present invention has the following features.
A transmission structure in which an isotropic region having a refractive index isotropic and an anisotropic region having a refractive index anisotropy are alternately stacked in a direction along a main surface of the optical substrate between two optical substrates. Type polarization selective hologram optical element, wherein the optical axis of the anisotropic region is substantially parallel to the light receiving surface of the polarization selective hologram optical element, and the isotropic region and the anisotropic region , And a difference between the ordinary light refractive index in the anisotropic region and the refractive index in the isotropic region is 0.01 or less.

In the image display device according to the present invention, an isotropic region having a refractive index isotropic and an anisotropic region having a refractive index anisotropy are alternately provided between two optical substrates. A transmission-type polarization-selective hologram optical element configured to be laminated and diffracted incident illumination light in a direction along the main surface of the substrate,
A reflection-type spatial light modulation element that modulates and reflects the polarization state of the illumination light diffracted by the polarization-selective hologram optical element. The light is oriented substantially parallel to the light receiving surface of the polarization selective hologram optical element and substantially parallel to the boundary between the isotropic region and the anisotropic region. The light is incident on the selective hologram optical element at an incident angle of 30 ° or more and less than 90 ° with respect to the normal of the illumination light receiving surface, and the S-polarized component of the illumination light is mainly directed to the reflection type spatial light modulator. When the illumination light modulated by the reflective spatial light modulator and re-entered has a diffraction efficiency of 10% or less with respect to the P-polarized component, it is possible to transmit 70% or more of the P-polarized component. Features .

The image display device according to the present invention comprises a light source that emits illumination light, an isotropic region having refractive index isotropic between two optical substrates, and an anisotropic region having refractive index anisotropy. And a transparent polarization selective hologram optical element for diffracting incident illumination light, and a diffractive light diffracted by the polarization selective hologram optical element, wherein the transparent regions are alternately stacked in a direction along the main surface of the optical substrate. A reflective spatial light modulator that modulates and reflects the polarization state of the illuminating light, an illumination optical system that guides the illumination light to a polarization-selective hologram optical element, and a screen that illuminates the illumination light modulated by the reflective spatial light modulator. A projection optical system for projecting the illumination light on the illumination light system. And select polarization In the selective hologram optical element, the optical axis of the anisotropic region is substantially parallel to the light-receiving surface of the polarization-selective hologram optical element, and at the boundary between the anisotropic region and the isotropic region. The illumination light is oriented so as to be substantially parallel to the light, mainly diffracts the S-polarized component of the illumination light toward the reflective spatial light modulator, and is re-incident after being modulated by the reflective spatial light modulator. In this case, the P-polarized light component is transmitted by 70% or more when the diffraction efficiency with respect to the P-polarized light component is 10% or less.

Further, the image display device according to the present invention comprises a light source for emitting illumination light, an isotropic region having refractive index isotropic between two optical substrates, and an anisotropic region having refractive index anisotropy. And a transmission type polarization-selective hologram optical element for diffracting incident illumination light, and diffracted by the polarization-selective hologram optical element. A reflective spatial light modulator that modulates and reflects the polarization state of the illumination light, an illumination optical system that guides the illumination light to the polarization-selective hologram optical element, and an observer that uses the illumination light modulated by the reflective spatial light modulator. A virtual image observation optical system for guiding to the pupil of the illumination optical system, the illumination optical system, the illumination light emitted from the light source is 30 ° or more and less than 90 ° with respect to the normal to the illumination light receiving surface of the polarization selective hologram optical element. Incident at incident angle, polarization selection The optical axis of the anisotropic region is substantially parallel to the light-receiving surface of the polarization-selective hologram optical element, and at the boundary between the anisotropic region and the isotropic region. It is oriented so as to be substantially parallel to the light, and mainly diffracts the S-polarized light component of the illumination light toward the reflective spatial light modulator, and is re-entered after being modulated by the reflective spatial light modulator. When the diffraction efficiency with respect to the P-polarized light component of the illumination light is 10% or less, 70% or more of the P-polarized light component is transmitted.

[0032]

Embodiments of the present invention will be described below with reference to the drawings.

[1] Embodiment of Polarization Selective Hologram Optical Element According to the Present Invention [1]-(1) Manufacturing Method First, a method of manufacturing a polarization selective hologram optical element according to the present invention will be described with reference to FIGS. This will be described with reference to FIG.

First, an alignment film 7 made of polyimide, silicon oxide, or the like is formed on two glass substrates 8 and 9 by a method such as spin coating or vapor deposition, and then heat-treated. Subsequently, a rubbing process is performed on these alignment films 7 in a certain direction using a roller or the like. Next, a sealant is applied to a peripheral portion of one glass substrate 8 except for one side, and a bead spacer having a diameter of about 4 μm to 10 μm is dispersed on the main surface of the other glass substrate 9.

The glass substrates 8 and 9 are arranged in such a manner that the rubbing directions are parallel and the directions are opposite.
At the same time, empty cells are created by laminating the alignment films 7 of the glass substrates 8 and 9 so that they face each other.

Then, a liquid material 4 containing a refractive index anisotropic material, for example, a liquid crystal material, a prepolymer, a mixed material of a dye or the like is injected from one side of the empty cell where the sealant is not applied. The prepolymer is composed of a photopolymerizable monomer (photopolymerizable polymer material), a thermopolymerizable monomer (thermopolymerizable polymer material), an oligomer, a reaction initiator, and the like. As the dye in the liquid material, for example, rose bengal or the like that absorbs visible light is used in order to manufacture this polarization selective hologram optical element using a visible light laser such as an argon ion laser. As a liquid crystal material, a nematic liquid crystal for a polymer dispersed liquid crystal is used.

After the liquid material has been injected into the empty cells, the injection port is sealed with a sealant to complete the pre-exposure panel.

Subsequently, the pre-exposure panel is exposed to an interference fringe 3 using an emission spectrum of an argon ion laser, for example, 488 nm. At this time, both the object light 1 and the reference light 2 from the argon ion laser that generate the interference fringes are parallel light beams, and therefore, the interference fringes 3 generated by these are linear. In FIG. 2, the light and dark states of the interference fringes are indicated by broken lines.

In this exposure, it is important to dispose the alignment film 7 so that the rubbing direction of the alignment film 7 coincides with the direction of the generated interference fringes. This is to make the optical axis of the liquid crystal molecules parallel to the interference fringes. Also, during the exposure of the interference fringes, the temperature of the pre-exposure panel, more precisely, the temperature of the liquid material in the pre-exposure panel is kept substantially constant in the range of about 20 ° C. to 70 ° C. Control it. Further, in order to more strongly control the alignment of the liquid crystal material contained in the liquid material 4, an external electric field, an external magnetic field, or light may be applied during exposure.

In this exposure step, in the bright portion of the interference fringe, the monomer is polymerized by photopolymerization due to the photon energy of the interference fringe. Thus, the bright part of the interference fringes
The polymer layer 5 mainly formed by photopolymerization is constituted. On the other hand, in the dark part of the interference fringes, the monomer is consumed for forming the polymer in the bright part, and as a result, the layer 6 containing a large amount of liquid crystal is formed. This process is called light-induced phase separation. Liquid crystal molecules gathered in the dark part of the interference fringes
In addition, the alignment control force by the external control means causes the optical axis to be oriented parallel to the linear interference fringes.

After this exposure step, ultraviolet rays are irradiated to fix or destroy the remaining monomers and dyes. This is called a fixing step. With this fixing step, the step of manufacturing the polarization selective hologram element is completed.

[1]-(2) Operation Principle Hereinafter, the operation principle of the transmission type polarization selective hologram optical element manufactured by the above-described manufacturing method will be described with reference to FIG. This polarization selective hologram optical element,
As described above, it is composed of the glass substrates 8 and 9, the alignment films 7 and 7, and the hologram layer 4. Further, the hologram layer 4
Is a state in which anisotropic regions 6 and isotropic regions 5 are alternately stacked in a direction along the main surfaces of the glass substrates 8 and 9.

It is assumed that the P-polarized light 1 and the S-polarized light 2 enter the polarization selective hologram optical element at an incident angle θin as shown in FIG. This incident angle θin
Is an angle in a plane where both incident light and diffracted light exist.

Anisotropic region 6 for incident P-polarized light 1
The optical axis of the liquid crystal molecules in the anisotropic region 6 is substantially parallel to the light receiving surface of the polarization selective hologram optical element, and the boundary between the isotropic region 5 and the anisotropic region 6 Since it is substantially parallel to the surface (substantially parallel to the interference fringes), the ordinary ray refractive index no of the anisotropic region 6 is always obtained regardless of the incident angle θin. On the other hand, the refractive index of the isotropic region 5 is always n
Poly. Here, no and nPol are equal (no =
nPoly), or by designing the difference between no and nPol to be 0.01 or less, the incident P-polarized light 1
Can be eliminated.

Regarding the refractive index of the anisotropic region 6 with respect to the incident S-polarized light 2, the optical axis of the liquid crystal molecules in the anisotropic region 6 is substantially equal to the light receiving surface of the polarization selective hologram optical element. Parallel and isotropic region 5 and anisotropic region 6
Of the incident angle θin
, The extraordinary ray refractive index ne of the anisotropic region 6 is always obtained. On the other hand, the refractive index of the isotropic region 5 is always npoly. Here, ne and nPol are equal (ne = nPoly,
Normally, this is only possible by using a liquid crystal material with a negative index ellipsoid where ne <no. ) Or by designing the difference between no and nPol to be 0.01 or less, it is possible to eliminate diffraction for the incident S-polarized light 2.

As described above, assuming that no and nPol are equal, the refractive index modulation Δn of the polarization-selective hologram optical element with respect to the incident S-polarized light 2 always takes the following value. .

Δn = | ne−no | If ne and nPol are equal, the refractive index modulation Δn of the polarization selective hologram optical element with respect to the incident P-polarized light 1 is always the following value. Become.

Δn = | ne-no | In the polarization-selective hologram optical element according to the present invention, as shown in FIG. 4, the refractive index of the isotropic region 5 (region 1) for S-polarized light is nS1, This is, for example, n
is set to 1.5, which is equal to o, and the refractive index of the anisotropic region 6 (region 2) with respect to the S-polarized light is set to nS2.
When it is set to 1.65 which is equal to e, the refractive index modulation degree Δn for the S-polarized light is always 0.15 regardless of the incident angle θin as follows.

NS1 = no = 1.5 nS2 = ne = 1.65 Δn = | 1.65-1.5 | = 0.15 However, as described above, the liquid crystal phase is completely separated by the photo-induced phase separation. Since there is no separation into the polymer phase and the order parameter of the liquid crystal contained in the liquid crystal phase is not 1,
It is extremely difficult to realize the idealized value of Δn (0.15).

[2] Embodiment of Image Display Device According to the Present Invention As shown in FIG. 5, a reflective image display device according to the present invention uses a polymer-dispersed liquid crystal (hereinafter referred to as “PDLC”) as a material. The liquid crystal panel described above can be used as a polarization selective hologram optical element.

The manufacturing method and operation principle of the polarization selective hologram optical element are the same as those described in the above-described embodiment of the polarization selective hologram optical element according to the present invention. In this image display device, all of the above-mentioned various polarization selective hologram optical devices according to the present invention can be used.

This image display device is configured such that a reflection type TN liquid crystal panel 11 which is a reflection type spatial light modulation device is optically adhered to an interface 12 with a polarization selective hologram optical element 10.

As shown in FIG. 5, the laminated structure of the isotropic region 5 and the anisotropic region 6 of the polarization selective hologram optical element 10 in this embodiment has the object light 13 incident at an incident angle of 0 °. And interference fringes caused by irradiation of the reference light 14 incident at an incident angle θin-air.

Here, the tilt angle θint of the interference fringes in the polarization selective hologram optical element 10 is obtained. Assuming that the refractive index of the glass substrate 8 is ngla and the average refractive index of the "PDLC" (liquid crystal layer) 4 is ngla for simplicity.
Then, the following relationship is established.

Ngla · sin [θin-med] = sin [θin-air] where θin-med is the angle of incidence in the medium. From this equation, assuming that ngla is 1.5 and θin-air is 60 °, θin-med is 35.3 °. Thus, the tilt angle θint of the interference fringes is obtained as follows.

Θint = θin−med / 2 = 17.7 ° Next, the operation principle of the image display device will be described.
Here, the reproduction light 1 including both the P-polarized component and the S-polarized component
4 is incident from the glass substrate 8 of the polarization selective hologram optical element 10 at an incident angle θin-air.

Here, the reproduction light is refracted on the incident surface of the glass substrate 8 and subsequently incident on the hologram layer 4 at an incident angle θin.
Inject at -med. At this time, as described above, the S-polarized light is diffracted in the polarization-selective hologram optical element 10 and is incident on the reflective TN liquid crystal panel 11 as incident light 15 which is substantially perpendicular.

The reflective TN liquid crystal panel 11 has a structure in which a TN liquid crystal layer 18 is interposed between a pair of glass substrates 16 and 17. One surface of the TN liquid crystal layer 18 and the glass substrate 1
The boundary surface with 7 is an aluminum reflection surface 19. In the reflective TN liquid crystal panel 11, the incident light 15
The light passes through the glass substrate 16 and the TN liquid crystal layer 18 on the side of the polarization selective hologram optical element 10, is reflected by the aluminum reflection surface 19, and is modulated by transmitting again through the TN liquid crystal layer 18. Again on the hologram layer 4.

The reflected light from the reflection type TN liquid crystal panel 11 re-entering the hologram layer 4 of the polarization selective hologram optical element 10 in this manner is reproduced as the emitted light 20 because the S-polarized component is diffracted again in the hologram layer 4. Light 14
The P-polarized component returns perpendicularly from the polarization-selective hologram optical element 10 as the emission light 21 without being diffracted by the hologram layer 4.

On the other hand, the P-polarized light component of the reproduction light 14 is not diffracted by the hologram layer 4 of the polarization-selective hologram optical element 10 and is incident on the reflection type TN liquid crystal panel 11 at an incident angle θin-med. I do. This P-polarized component is
Although the polarization state is modulated by passing through the TN liquid crystal layer 18 of the reflective TN liquid crystal panel 11, the aluminum reflective surface 1
The reflected light 22 reflected by 9 does not match the diffraction condition because the hologram layer 4 of the polarization selective hologram optical element 10 is a thick hologram, and not only the P polarization component but also the S polarization component The light passes through the polarization-selective hologram optical element 10 without being diffracted by the hologram layer 4.

Even if a part of the S-polarized light component modulated by the reflective TN liquid crystal panel 11 of the P-polarized light component of the reproduction light 14 is diffracted by the hologram layer 4 of the polarization selective hologram optical element 10, The direction of emission of the diffracted light is changed to the emission light 21 (the P light modulated by the reflective TN liquid crystal panel 11 of the S-polarized light component of the reproduction light 14) which is emitted substantially perpendicularly from the polarization selective hologram optical element 10. By setting the direction sufficiently different from the emission direction of the (polarized light component), or by installing a polarizing plate in the optical path of the emitted light 21 for selectively transmitting the polarized light component mainly included in the emitted light 21, These diffracted light and emitted light 21 can be separated well.

Here, a thick hologram will be described. In general, a thick hologram is often defined as having a Q value of 10 or more as follows. Reference books detailing the Q value include “Holographie” (Shokabo) by Junpei Tsujiuchi.

Q = 2πλt / (nΛΛ) where λ is the reproduction wavelength, t is the thickness of the hologram layer,
n, the average refractive index of the hologram layer, Λ is the pitch of interference fringes. The pitch 干 渉 of the interference fringes is shown as follows.

Λ = λc / | 2 sin [(θs−θr) / 2] | where λc is the production wavelength, θs is the incident angle of the object light,
θr is the incident angle of the reference light.

From these equations, for example, λc is set to 0.55
μm, θs is 60 °, θr is 0 °, λ is 0.55 μm,
If t is 5 μm and n is 1.5, the pitch of the interference fringes Λ
Is 0.55 μm and Q is 38.1, which corresponds to the definition of a thick hologram.

A thick hologram has a high diffraction efficiency, but the diffraction efficiency drops sharply when the conditions of the reproduction light deviate from the conditions such as the wavelength used during manufacture and the incident angles of the object light and the reference light. have. That is, at a certain reproducing wavelength, if the incident angle of the reproducing light deviates greatly from the incident angle at which the diffraction efficiency becomes a peak, the diffraction effect is not exhibited. Therefore, as described above, the reproduction light 14
The reflected light 22 of the P-polarized component reflected by the aluminum reflective surface 19 of the reflective TN liquid crystal panel 11 has a polarization selectivity even if it is modulated by the reflective TN liquid crystal panel 11 to have an S-polarized component. The hologram layer 4 of the hologram optical element 10 is hardly diffracted.

In the polarization-selective hologram optical element 10 according to the present invention, in order to obtain high diffraction efficiency, the bend angle | θs−θr | Is set to However,
If the vent angle is too large, for example, 80 ° or more, the wavelength band in which the diffraction effect occurs and the incident angle range are reduced, and the light use efficiency is reduced.

Here, the polarization selective hologram optical element 1
0 and the incident angle θin−air of the polarization selective hologram optical element 10 to the hologram layer 4.
Think about med. As described above, the relationship between the two is as follows.

Ngla · sin [θin-med] = sin [θin-air] Here, paying attention to the rate of change of both, for example, assuming that the refractive index ngla of the glass substrate 8 is 1.5, the reproduced light incident angle θin− a
When ir changes by 10 ° from 55 ° to 65 °, the angle of incidence θin-med on the hologram layer 4 changes from 33.1 ° to 37.
The change is only 2 ° and 4.1 °. Reproduction light incident angle θin
If -air changes 10 ° from 65 ° to 75 °,
The incident angle θin-med to the hologram layer 4 changes from 37.2 ° to 40.1 °, which is a change of 2.9 °. This is nothing but moving the place where the change rate of the sine function is large to a place where the change rate is small by applying a certain magnification (in this case, the reciprocal of the refractive index ngla of the glass substrate 8). This means that the deterioration of the uniformity and the decrease of the diffraction efficiency of the polarization selective hologram optical element 10 depending on the incident angle of the reproduction light are reduced as described above.

The change rate of the incident angle θin-med to the hologram layer 4 with respect to the reproduction light incident angle θin-air becomes smaller as the refractive index ngla of the glass substrate 8 becomes larger.
For example, when the refractive index ngla of the glass substrate 8 is 1.73, when the incident angle θin-air of the reproduction light changes from 55 ° to 65 °, the incident angle θin-med to the hologram layer 4 becomes:
From 28.3 ° to 31.6 °, the change is only 3.3 °.

However, the polarization selective hologram optical element 1
The reproduction light incident angle θin-air to 0 is, for example,
If the angle is too large, such as 75 ° or more, the surface reflectance on the incident surface of the glass substrate 88 will increase, and it will be difficult to suppress it with an antireflection film or the like.

Therefore, the polarization selective hologram optical element 1
In the case where the incident angle θin-air of the reproduction light to zero exceeds 75 °, as shown in FIG.
It is effective to use 3. The coupling prism 23 is formed of the same material as the substrate 8 on the side where the reproduction light is incident.
4 and is arranged on the incident surface 4 so as to be joined to the incident surface.
The coupling prism 23 has a reproduction light incident surface that is inclined with respect to the incident surface of the reproduction light 14 of the polarization selective hologram optical element 10.

When the coupling prism 23 is used as described above, the polarization selective hologram optical element 1
The incident angle θin-air of the reproduction light to 0 becomes equal to the incident angle θin-med of the reproduction light to the hologram layer 4. For this reason, if the hologram layer 4 itself does not have a sufficiently wide allowable range of the incident angle of the reproduction light, the light use efficiency is reduced.

Therefore, in the reflection type image display device according to the present invention, when the coupling prism 23 is used, the diffracted light in the hologram layer 4 of the polarization selective hologram optical element 10 is substantially vertically reflected by the reflection type space. The bend angle is 30 ° under the condition that the light enters the light modulation element 11.
The angle of incidence on the polarization-selective hologram optical element 10, that is, 30 °, is defined as the minimum angle of incidence on the polarization-selective hologram optical element 10.

In order to maintain high diffraction efficiency with respect to high-band reproduction light, as shown in FIG. 7, a plurality of polarization-selective hologram optical elements 10r, 10g, and 10b are laminated to reproduce light. The wavelength band of the light 14 is divided into a plurality of parts, each band is diffracted by one corresponding polarization selective hologram optical element, and each wavelength band is incident on the reflection-type spatial light modulator 11 substantially perpendicularly for illumination. Illumination light.

In the embodiment shown here, the polarization selective hologram optical element has three layers. However, in this image display element, the polarization selective hologram optical element may have four or more layers. And two layers.

In order to maintain a high diffraction efficiency even when the incident angle range of the reproduction light 14 is large, a plurality of polarization selective hologram optical elements having different acceptance ranges of the incident angle of the reproduction light are laminated. In each polarization-selective hologram optical element, it is preferable to diffract the reproduction light in the incident angle range corresponding to each.

Furthermore, by laminating polarization selective hologram optical elements having different diffraction wavelength bands and different acceptance ranges of incident angles of reproduction light, or by superimposing them by multiple exposure, the target wavelength band is wide, and Thus, it is possible to realize an image display device having a wide acceptance angle of a reproduction light incident angle.

[3] Embodiment of Image Display Apparatus (Projection Type) According to the Present Invention In the image display apparatus according to the present invention, all of the various image display elements according to the present invention described above are used. be able to. As shown in FIG. 8, the image display device according to the present invention has a reflective spatial light
It can be configured as a color projection type image display device having two reflective TN vertical alignment liquid crystal panels.

In this image display device, the illumination light source 2
The illumination light emitted from 4 enters the illumination optical system 25. The illumination optical system 25 has functions such as correction of the cross-sectional shape of the light flux of the illumination light, uniformization of the intensity, and control of the divergence angle. Further, the illumination optical system 25 has a polarization conversion means 26, and the P-polarized light of the illumination light so that the incident light to the polarization selective hologram optical element described later becomes, for example, S-polarized light. The component is converted into S-polarized light by rotating the polarization direction of the component by 90 °, thereby improving the light use efficiency.

The light beam that has passed through the illumination optical system 25 passes through a polarizing plate 27 that selectively transmits S-polarized light, and then passes through a mirror 28.
The optical path is bent at and the light enters the polarization selective hologram optical element 10. The polarization-selective hologram optical element 10 is composed of five hologram layers having different target light wavelength bands and target light incident angle acceptance ranges. In the polarization-selective hologram optical element 10, the S-polarized light component of the reproduction light is diffracted from the polarization-selective hologram optical element 10 so as to be emitted substantially vertically, and enters the dichroic prism block 29.

This dichroic prism block 29
In the S-polarized light of the incident reproduction light, the blue component light is reflected by the blue light reflective thin film 29b, and the green component light is reflected by the green light reflective thin film 29g, so that R (red) G (Green) It is separated into each color of B (blue).

The respective color component lights separated in the dichroic prism block 29 are incident on the reflection type spatial light modulation elements 11r, 11g and 11b corresponding to each color substantially perpendicularly, respectively.
r, 11g, 11b, for each color component light,
The polarization state is modulated and reflected for each pixel.

Each of the reflective spatial light modulators 11r, 11g,
Each color component light modulated in 11b again enters the cross dichroic prism block 29, is recombined, and enters the polarization selective hologram optical element 10. At this time, the P-polarized component light is transmitted without being diffracted, and the S-polarized component light is diffracted and returns to the illumination optical system 25 side. The P-polarized component light transmitted through the polarization-selective hologram optical element 10 without being diffracted is incident on the projection optical system 31 via the polarizing plate 30 that selectively transmits the P-polarized light. The projection optical system 31 forms an incident light beam as an image on a screen (not shown). The image formed on the screen is an image formed by modulating each pixel in each of the reflective spatial light modulators 11r, 11g, and 11b.

The illumination optical system 25 converts the illumination light radiated from the illumination light source 24 to a normal to the illumination light receiving surface of the polarization selective hologram optical element 30 through a mirror 28.
The light is incident at an incident angle of at least 90 ° and less than 90 °. The polarization-selective hologram optical element 10 having the above-described configuration diffracts the S-polarized light component of the illumination light toward the reflection-type spatial light modulators 11r, 11g, and 11b. Since the diffraction efficiency with respect to the P-polarized component of the illumination light modulated by the elements 11r, 11g, and 11b and re-entered is 10% or less, this P
Transmits 70% or more of the polarized light component. This is the same in the embodiments described below.

The illumination optical system 25 may include a polarization-selective hologram optical element for correction having a bend angle opposite to that of the polarization-selective hologram optical element 10. This is the same in the embodiments described below.

Further, the image display device according to the present invention has the configuration shown in FIG.
As shown in (1), it is also possible to use a transmissive liquid crystal spatial light modulator. In this image display device, a light beam emitted from a lamp light source 24 enters an illumination optical system 25 having functions such as correction of a light beam cross-sectional shape, uniform intensity, and divergence angle control. The illumination optical system 25 includes a PS polarization converter 26 having a function of aligning a non-polarized light beam with either P-polarized light or S-polarized light with an efficiency of 50% or more. In the case of this embodiment, the light beam that has passed through the illumination optical system 25 has a polarization state in which the electric vector oscillates in a direction perpendicular to the paper surface in FIG. 9, that is, a polarization selective hologram optical element of a polarization splitting element that subsequently enters. 10 is converted to S-polarized light.

The luminous flux emitted from the illumination optical system 25 travels straight without being diffracted by the polarization selective hologram optical element 10 and enters the total reflection prism 40 from the first optical surface. After the traveling direction is changed by 90 ° on the second optical surface (total reflection surface) 41 of the total reflection prism 40, the light is emitted from the total reflection prism 40 on the third optical surface 42. The polarization selective hologram optical element 10 is optically attached to the first optical surface of the total reflection prism 40.

The P-polarized light remaining without being converted by the PS polarization converter 26 is diffracted by the polarization selective hologram optical element 10 in the direction of arrow A in FIG. The light exits from the total reflection prism 40 at the (reflection surface) 41.
Therefore, most of the illumination light emitted from the polarization splitting element is S-polarized light. The traveling direction of the green light and the red light is turned by 90 ° by the green and red light reflecting dichroic mirrors 44 through the condenser lens 43, and then the green light reflecting dichroic mirror 4 is turned on.
At 5, only the green light is reflected.

In this way, the illumination light is separated into blue (B), green (G), and red (R) light. Blue (B)
The color light passes through a condenser lens 52, a mirror 53, and a condenser lens 54, and enters a transmissive liquid crystal spatial light modulator (for blue) 55. The green (G) light passes through a condenser lens 56 and passes through a transmissive liquid crystal spatial light modulator (for green) 5.
7 is incident. The red (R) light is transmitted through the condenser lens 4
6, mirror 47, condenser lens 48, mirror 49,
After passing through a condenser lens 50, the light enters a transmissive liquid crystal spatial light modulator (for red) 51.

Each of the transmissive liquid crystal spatial light modulators 55, 57,
The illumination light transmitted through 51 is subjected to color synthesis in a cross dichroic prism 58 and projected on a screen (not shown) by the projection optical system 31.

In this image display device, the incident light on each of the transmission type liquid crystal spatial light modulators 55, 57 and 51 has already been detected as S-polarized light by the polarization splitter, so that the transmission type liquid crystal spatial light modulator is used. Since there is almost no absorption by the polarizers on the incident side of the modulation elements 55, 57, and 51, even when a bright image can be projected using a high-output light source, a high-contrast image and reliability can be obtained. Can be realized.

Further, as shown in FIG. 10, the image display device according to the present invention is configured as a color projection type image display device using one reflective FLC panel 11 as a reflective spatial light modulator. Can also.

In this image display device, the illumination light source 2
The illumination light emitted from 4 has an illumination optical system 2 having functions such as correction of a light beam cross-sectional shape, uniform intensity, and divergence angle control.
5 is incident. The illumination optical system 25 includes a polarization conversion unit (not shown). In the illumination optical system 25,
Color wheel 5 serving as time-sequential wavelength band switching means
9 are provided. The color wheel 59 time-divides the white light emitted from the illumination light source 24 into red, green, and blue light spectral components. Thus, the color wheel 59 is a single plate of the reflection-type FLC panel 11 and has a field sequential color. Color display by the method becomes possible.

The illumination light enters the polarization selective hologram optical element 10 via the mirror 28. Most of the S-polarized component of this illumination light is diffracted and the traveling direction of the light can be changed.
P-polarized light travels straight without being diffracted. Therefore, on the second optical surface 41 of the triangular prism 40 provided with the first optical surface in close contact with the polarization-selective hologram optical element 10, the S-polarized light component that is undiffracted light (zero-order light) Are totally reflected and emitted from the third optical surface (exit surface), and do not enter the reflective FLC panel 11.

On the other hand, the polarization selective hologram optical element 10
Is emitted from the second optical surface 41 of the triangular prism 40, and then the S-polarized light,
After passing through 0, the light enters the reflective FLC panel 11. The illumination light whose polarization direction has been modulated in accordance with the display image in the reflection type FLC panel 11 is again transmitted to the correction prisms 60 and 3.
The light enters the polarization-selective hologram optical element 10 through the prism 40. Here, most of the S-polarized light component is diffracted and returned to the incident direction of the illumination light, and the P-polarized light passes straight without being diffracted. Here, since the S-polarized light is also included in the light that travels straight without being diffracted in the polarization-selective hologram optical element 10, the polarizing plate selectively transmits the S-polarized component, that is, blocks the P-polarized component. 61
And detect. The light transmitted through the polarizing plate 61 is
The projection optical system 31 causes the reflection type FL on the screen 52.
An enlarged image of the C panel 11 is formed.

The reflection type spatial light modulation element 11 has a rectangular screen (polarization modulation area), and is disposed such that its longitudinal direction a coincides with the direction of the incident angle of the illumination light. This is a horizontal alignment polarization selective hologram optical element 1
This is because the effective width of the incident illumination light is reduced due to the oblique incidence of the illumination light incident on 0, and the amount of reduction in the effective width is reduced as much as possible to increase the light use efficiency.

Further, for the same reason, the longitudinal direction of the light emitting portion of the illumination light source 24 is perpendicular to the plane of FIG. This is because the smaller the light emitting portion is, the smaller the light beam diameter is, the harder the diffusion angle becomes when compared with the Lagrangian-Helmholtz invariant, so that the illumination light is obliquely applied to the spatial light modulator as in the present invention. This is because, when the light is made incident, it is effective to shorten the length of the light emitting portion in a direction corresponding to the incident direction in order to increase the light use efficiency.

Further, the polarizing plate 61 is used to correct the aberration of the modulated light having astigmatism caused by passing through the polarization selective hologram optical element 10, the correcting prism 60, and the triangular prism 40. They are arranged with opposite inclination angles. Thereby, astigmatism of the modulated light can be canceled, and a clear image display can be performed.

[4] Embodiment of Image Display Apparatus (Virtual Image Type) According to the Present Invention As shown in FIG. 11, the image display apparatus according to the present invention employs a reflective FLC panel as a reflective spatial light modulator as shown in FIG. 3
2 and a virtual image forming optical system.

In this image display apparatus, the illumination light emitted from the light emitting diode light source with lens 33 that sequentially emits three colors of red light, green light and blue light selectively transmits a P-polarized component. The light passes through the polarizing plate 34 and enters the polarization selective hologram optical element 10. This incident light is diffracted by the polarization selective hologram optical element 10 and is incident on the reflective FLC panel 32 substantially vertically.

The illumination light whose phase has been modulated by the reflection type FLC panel 32 is reflected by the aluminum reflection surface 19 of the reflection type FLC panel 32 and again enters the polarization selective hologram optical element 10. At this time, the P-polarized light component is diffracted again by the polarization-selective hologram optical element 10 and travels toward the light-emitting diode light source 33, but the S-polarized light component is not diffracted by the polarization-selective hologram optical element 10 and remains as it is. To Penetrate. The S-polarized light transmitted through the polarization-selective hologram optical element 10 is detected by a polarizing plate 35 that selectively transmits the S-polarized component, and then is subjected to free-form surface refraction by a free-form surface prism 36 constituting a virtual image observation optical system. The light enters from the surface 37.

The light incident on the free-form surface prism 36 is
After being totally reflected on the first optical surface 38 and then reflected on the second free-form surface reflecting surface 39, the light is transmitted through the first optical surface 38 and guided to the observation region 40 of the observer. At this time, in order to enlarge the observation region 40, a diffusion plate is disposed between the light emitting diode light source 33 and the polarizing plate 34,
Alternatively, in the polarization selective hologram optical element 10,
Interference fringes that cause a diffusion effect on the P-polarized light component incident on the polarization-selective hologram optical element 10 during diffraction may be recorded in advance.

[0104]

As described above, the polarization selective hologram optical element according to the present invention has a refractive index modulation type polarization structure having a structure in which optically isotropic regions and anisotropic regions are alternately laminated. This is a selective hologram element, which has improved polarization separation performance as compared with a conventional refractive index modulation type polarization selective hologram element having a structure in which isotropic regions having different refractive indexes are alternately stacked.

In the polarization-selective hologram optical element according to the present invention, the optical axis of the anisotropic region is substantially parallel to the plane of incidence of the reconstructed light, and the isotropic region and the anisotropic region Are oriented substantially parallel to the boundary surface, so that there is no conventional refractive index modulation type polarization selective hologram element having a structure in which anisotropic regions are alternately stacked, and no active alignment control means. Compared with a refractive index modulation type polarization selective hologram element having a structure in which an isotropic region and an anisotropic region are alternately stacked, a decrease in diffraction efficiency depending on the incident angle of the reproduction light is suppressed.

In the polarization-selective hologram optical element according to the present invention, a liquid-crystal material is used as the anisotropic substance existing in the anisotropic region, and the orientation of the liquid-crystal material is controlled to thereby provide a polarization-selective hologram. The polarization separation characteristics and the diffraction efficiency of the optical element are improved.

Further, in the polarization selective hologram optical element according to the present invention, the reliability can be improved by using a photocurable liquid crystal as a liquid crystal material and curing the liquid crystal in a state where the alignment is regulated.

The image display device and the image display device according to the present invention are configured by using the above-described image display device according to the present invention, so that the polarizing beam splitter can be used as an illuminating means for the reflective spatial light modulator. Because it is not necessary to use, it can be configured to be small and lightweight,
Problems such as contrast of a displayed image and manufacturing cost are improved.

That is, the present invention provides a polarization-selective hologram optical element capable of obtaining good polarization separation characteristics not only when the incident angle of the incident light beam is small but also when the incident angle is large. Can be provided.

Further, according to the present invention, by using the above-described polarization-selective hologram optical element according to the present invention, it is possible to realize a small and lightweight structure, high light use efficiency, high display image contrast and high reliability. It is possible to provide an image display device and an image display device which have high performance and whose manufacturing cost is suppressed.

[Brief description of the drawings]

FIG. 1 is a plan view showing a configuration of a polarization selective hologram optical element according to the present invention.

FIG. 2 is a longitudinal sectional view showing a configuration of the polarization selective hologram optical element.

FIG. 3 is a longitudinal sectional view showing an operation principle of the polarization selective hologram optical element.

FIG. 4 is a side view showing characteristics of the polarization-selective hologram optical element when the incident angle of the reproduction light changes.

FIG. 5 is a longitudinal sectional view showing a configuration of an image display device according to the present invention.

FIG. 6 is a longitudinal sectional view showing a configuration in which a coupling prism is provided in the image display element.

FIG. 7 is a longitudinal sectional view showing a configuration in which a polarization-selective hologram optical element is formed as a multilayer in the image display element.

FIG. 8 is a plan view showing the configuration of an image display device according to the present invention, which has a dichroic prism, a reflective spatial light modulator (three plates), and a projection optical system.

FIG. 9 is a plan view showing a configuration of the image display device having a dichroic mirror, a transmission type spatial modulation element (three plates), and a projection optical system.

FIG. 10 is a plan view showing a configuration of the image display device having a reflective spatial light modulator (single plate) and a projection optical system.

FIG. 11 is a side view showing a configuration of the image display device having a reflective spatial light modulator (single plate) and a virtual image optical system.

FIG. 12 is a graph showing a relationship between a change in diffraction efficiency and a thickness t of the hologram and a pitch 干 渉 of interference fringes in the hologram in the reflection hologram.

FIG. 13 is a longitudinal sectional view showing a configuration of a conventional image display element.

FIG. 14 is a longitudinal sectional view illustrating a method for manufacturing a conventional polarization-selective hologram optical element.

FIG. 15 is a longitudinal sectional view showing a configuration of a conventional polarization-selective hologram optical element in which the alignment direction of liquid crystal is controlled by applying a voltage.

FIG. 16 is a longitudinal sectional view showing a conventional polarization-selective hologram optical element in which a voltage is applied to control the orientation direction of liquid crystal.

FIG. 17 shows a conventional polarization-selective hologram optical element having an isotropic region and an anisotropic region, wherein the optical axis direction of the anisotropic region is at the boundary between the isotropic region and the anisotropic region. It is a longitudinal section showing the composition of what is perpendicular.

FIG. 18 shows a conventional polarization-selective hologram optical element having two anisotropic regions, in which the optical axis direction in each anisotropic region is perpendicular to the boundary between the anisotropic regions, and reproduction light. It is a longitudinal cross-sectional view which shows the structure of what becomes a direction perpendicular | vertical to an incidence surface.

FIG. 19 is a longitudinal sectional view showing the configuration of the conventional polarization selective hologram optical element shown in FIG.

FIG. 20 is a conventional polarization-selective hologram optical element having two anisotropic regions, wherein the optical axis direction in each anisotropic region is parallel to the boundary surface between the anisotropic regions and the reproduction light incident surface. FIG. 3 is a vertical cross-sectional view showing the configuration of a direction perpendicular to the reproduction light incidence surface and a direction perpendicular to the reproduction light incidence surface.

FIG. 21 is a conventional polarization-selective hologram optical element having two anisotropic regions, wherein the optical axis direction in each anisotropic region is parallel to the boundary between the anisotropic regions and the reproduction light incident surface. FIG. 4 is a longitudinal sectional view showing a configuration of a direction perpendicular to a boundary surface between anisotropic regions and a direction perpendicular to each other.

FIG. 22 shows a configuration of a conventional polarization-selective hologram optical element having an isotropic region and an anisotropic region, wherein the optical axis direction of the anisotropic region is perpendicular to the reproduction light incident surface. It is a longitudinal cross-sectional view.

[Explanation of symbols]

1 object light, 2 reference light, 3 interference fringes, 4 liquid crystal layer, 5
Isotropic region, 6 Anisotropic region, 7 Alignment film, 8, 9
Glass substrate, 10 polarization selective hologram optical element, 11
Reflective TN liquid crystal panel

Claims (94)

[Claims] 1. A direction along a main surface of an optical substrate, wherein an isotropic region having a refractive index isotropic and an anisotropic region having a refractive index anisotropy are alternately provided between two optical substrates. A transmission-type polarization-selective hologram optical element configured to be laminated on the optical axis, wherein the optical axis of the anisotropic region is substantially parallel to the light-receiving surface of the polarization-selective hologram optical element, and It is oriented substantially parallel to the interface between the isotropic region and the anisotropic region, and the difference between the ordinary light refractive index of the anisotropic region and the refractive index of the isotropic region is 0.01. A polarization-selective hologram optical element, characterized in that: 2. The polarization-selective hologram optical element according to claim 1, wherein the isotropic region is mainly composed of a photopolymerizable polymer material or a thermopolymerizable polymer material. 3. The polarization selective hologram optical element according to claim 1, wherein the anisotropic region contains a liquid crystal material. 4. The polarization-selective hologram optical element according to claim 3, wherein the liquid crystal material has its alignment controlled by an alignment control means. 5. The liquid crystal material alignment control means irradiates an alignment film provided on an optical substrate, an electric or magnetic field applied to the polarization selective hologram optical element, or irradiates the polarization selective hologram optical element. 5. The polarization-selective hologram optical element according to claim 4, wherein the selected one of the light beams or a combination thereof is used. 6. The liquid crystal material is a photo-curable liquid crystal, and in an uncured state, its alignment is controlled by an alignment control means.
4. The polarization-selective hologram optical element according to claim 3, wherein the liquid crystal is cured by being irradiated with a light beam having a wavelength for curing the photocurable liquid crystal. 7. The liquid crystal material alignment control means irradiates the alignment film provided on the optical substrate, the electric field or magnetic field applied to the polarization selective hologram optical element, or the polarization selective hologram optical element. 7. The polarization-selective hologram optical element according to claim 6, wherein the light beam is one of the light beams to be emitted or a combination thereof. 8. The two optical substrates have transparent electrodes, and an electric field generated by a voltage applied to these transparent electrodes causes
2. The polarization selective hologram optical element according to claim 1, wherein the optical axis direction of the anisotropic substance is variably controlled. 9. An optically isotropic region having a refractive index isotropic property and an anisotropic region having a refractive index anisotropy are alternately stacked between two optical substrates in a direction along a main surface of the optical substrate. A transmission-type polarization-selective hologram optical element configured to diffract incident illumination light; and a reflection-type spatial light that modulates and reflects the polarization state of the illumination light diffracted by the polarization-selection hologram optical element. A polarization element, wherein the polarization-selective hologram optical element has an optical axis of the anisotropic region substantially parallel to a light-receiving surface of the polarization-selective hologram optical element, and an isotropic region. And the alignment light is oriented substantially parallel to the boundary surface between the anisotropic region and the illumination light is at least 30 ° and less than 90 ° with respect to the normal to the illumination light receiving surface of the polarization selective hologram optical element. The illumination light is incident at an incident angle, and the S-polarized light The diffracted light is mainly diffracted toward the reflective spatial light modulator, and the diffraction efficiency for the P-polarized light component of the illumination light modulated by the reflective spatial light modulator and re-entered is 10% or less. And an image display device transmitting 70% or more of the P-polarized light component. 10. The image display device according to claim 9, wherein the isotropic region is mainly composed of a photopolymerizable polymer material or a thermopolymerizable polymer material. 11. The image display device according to claim 9, wherein the anisotropic region contains a liquid crystal material. 12. The image display device according to claim 11, wherein the alignment of the liquid crystal material is controlled by an alignment control unit. 13. An alignment control means for a liquid crystal material, comprising: an alignment film provided on an optical substrate; or an electric or magnetic field applied to the polarization selective hologram optical element;
13. The image display device according to claim 12, wherein any one of the light beams irradiated to the polarization selective hologram optical element or a combination thereof is used. 14. The liquid crystal material is a photocurable liquid crystal,
The alignment is controlled by an alignment regulating means in an uncured state, and the liquid crystal is cured by being irradiated with a light beam having a wavelength for curing the photocurable liquid crystal.
The image display device as described in the above. 15. An alignment control means for a liquid crystal material, comprising: an alignment film provided on an optical substrate; or an electric or magnetic field applied to the polarization selective hologram optical element;
15. The image display device according to claim 14, wherein the light beam is one of the light beams applied to the polarization selective hologram optical element or a combination thereof. 16. The two optical substrates have transparent electrodes,
10. The image display device according to claim 9, wherein the azimuth of the optical axis of the anisotropic substance is variably controlled by an electric field generated by a voltage applied to the transparent electrode. 17. The image according to claim 9, wherein a bend angle, which is a difference between an incident angle of illumination light and an exit angle of diffracted light with respect to a hologram surface of the polarization selective hologram optical element, is 30 ° or more. Display element. 18. The image display according to claim 9, wherein the diffracted light from the polarization-selective hologram optical element is emitted while being inclined with respect to the normal to the illumination light incident surface of the polarization-selective hologram optical element. element. 19. The image display device according to claim 9, wherein the polarization-selective hologram optical element is constituted by a plurality of hologram layers having different wavelength dependences of diffraction efficiency. 20. The image display device according to claim 9, wherein the polarization-selective hologram optical element is constituted by a plurality of hologram layers having different diffraction light incident angle dependences of diffraction efficiency. 21. The image display device according to claim 9, wherein the polarization-selective hologram optical element has a plurality of holograms having different diffraction efficiency wavelength dependences multiplexed in one hologram layer. 22. The image according to claim 9, wherein the polarization-selective hologram optical element comprises a plurality of holograms having different diffraction efficiencies depending on a reconstructed light incident angle, which are multiplexed on one hologram layer. Display element. 23. The image display device according to claim 9, wherein the polarization selective hologram optical device and the reflection type spatial light modulation device are optically adhered and integrally formed. 24. A light source for emitting illumination light, and an isotropic region having a refractive index isotropic property and an anisotropic region having a refractive index anisotropy between two optical substrates are alternately arranged on the optical substrate. A transmission-type polarization-selective hologram optical element configured to be laminated in a direction along a main surface of the optical element and diffracting incident illumination light; and a polarization state of the illumination light diffracted by the polarization-selective hologram optical element is modulated. A reflective spatial light modulator that reflects the reflected light, an illumination optical system that guides the illumination light to the polarization-selective hologram optical element, and a projection that projects the illumination light modulated by the reflective spatial light modulator on a screen An illumination system, wherein the illumination optical system emits illumination light emitted from the light source at an incident angle of 30 ° or more and less than 90 ° with respect to a normal to an illumination light receiving surface of the polarization selective hologram optical element. Incident, polarized above The selective hologram optical element has an optical axis of the anisotropic region substantially parallel to a light receiving surface of the polarization selective hologram optical element and a boundary between the anisotropic region and the isotropic region. It is oriented so as to be substantially parallel to the surface, and mainly diffracts the S-polarized component of the illumination light toward the reflective spatial light modulator, and is modulated by the reflective spatial light modulator. P of the re-entered illumination light
An image display device characterized by transmitting 70% or more of the P-polarized light component when the diffraction efficiency for the polarized light component is 10% or less. 25. The image display device according to claim 24, wherein the isotropic region is mainly made of a photopolymerizable polymer material or a thermopolymerizable polymer material. 26. The image display device according to claim 24, wherein the anisotropic region contains a liquid crystal material. 27. The image display device according to claim 26, wherein the alignment of the liquid crystal material is controlled by alignment control means. 28. An alignment control means for a liquid crystal material, comprising: an alignment film provided on an optical substrate; or an electric or magnetic field applied to the polarization-selective hologram optical element;
28. The image display device according to claim 27, wherein any one of the light beams applied to the polarization selective hologram optical element or a combination thereof is used. 29. The liquid crystal material is a photocurable liquid crystal,
27. An uncured state in which alignment is controlled by an alignment regulating means, and the liquid crystal is cured by being irradiated with a light beam having a wavelength for curing the photocurable liquid crystal.
The image display device as described in the above. 30. An alignment control means for a liquid crystal material, comprising: an alignment film provided on an optical substrate; or an electric or magnetic field applied to the polarization selective hologram optical element;
30. The image display device according to claim 29, wherein any one of the light beams applied to the polarization selective hologram optical element or a combination thereof is used. 31. Two optical substrates each having a transparent electrode,
25. The image display device according to claim 24, wherein the optical axis direction of the anisotropic substance is variably controlled by an electric field generated by a voltage applied to the transparent electrode. 32. The light source has a rectangular light-emitting portion, and the short side direction of the light-emitting portion is made to coincide with the incident direction of illumination light to the polarization-selective hologram optical element. The image display device according to claim 24. 33. A polarization conversion means for rotating a polarization direction by 90 ° of a component of the illumination light having a polarization direction orthogonal to the polarization direction at which the diffraction efficiency of the polarization selective hologram optical element is maximized. The image display device according to claim 24, further comprising: 34. The illumination optical system further comprises a polarization selection unit for selectively transmitting a component having a polarization orientation that maximizes the diffraction efficiency of the polarization-selective hologram optical element in the illumination light. The image display device according to claim 24, wherein: 35. A light source or an illumination optical system comprising time sequential wavelength band switching means for transmitting only a plurality of specific wavelength bands out of the entire wavelength band of the illumination light in time sequence. The image display device according to claim 24, wherein: 36. The image display apparatus according to claim 24, wherein the illumination optical system includes a correction polarization selective hologram optical element having a bend angle of the opposite sign to the polarization selective hologram optical element. 37. The image display device according to claim 24, wherein the polarization selective hologram optical element for correction is the same element as the polarization selective hologram optical element. 38. A first optical surface which is optically adhered to a polarization selective hologram optical element and at least illumination light is incident substantially perpendicularly, and light reflected by the reflection type spatial light modulation element is emitted substantially perpendicularly. And a coupling prism having a second optical surface. The polarization-selective hologram optical element receives illumination light at an incident angle of 60 ° or more and less than 90 ° with respect to a normal to the illumination light receiving surface. The image display device according to claim 24, wherein: 39. The coupling prism has a third optical surface provided with a light absorbing layer on which specular reflection light of illumination light from the reflection type spatial light modulation element is incident substantially perpendicularly. The image display device according to claim 38, wherein: 40. A projection optical system, comprising: a polarization selecting means for selectively transmitting a component of a polarization azimuth transmitted through the polarization-selective hologram optical element, of the light modulated by the reflection-type spatial light modulation element. The image display device according to claim 24, wherein: 41. The image according to claim 24, wherein a bend angle, which is a difference between an incident angle of the illumination light and an exit angle of the diffracted light with respect to the hologram surface of the polarization selective hologram optical element, is 30 ° or more. Display device. 42. The image display according to claim 24, wherein the hologram surface of the polarization-selective hologram optical element and the reflection surface of the reflective spatial light modulator have an optically inclined positional relationship. apparatus. 43. The image display device according to claim 24, wherein the polarization-selective hologram optical element is constituted by a plurality of hologram layers having different wavelength dependences of diffraction efficiency. 44. The image display device according to claim 24, wherein the polarization-selective hologram optical element is constituted by a plurality of hologram layers having different diffraction light dependences on the incident angle of the reproduction light. 45. The image display device according to claim 24, wherein the polarization-selective hologram optical element is configured such that a plurality of holograms having different wavelength dependences of diffraction efficiency are multiplexed on one hologram layer. 46. The image according to claim 24, wherein in the polarization selective hologram optical element, a plurality of holograms having different diffraction light dependences of the diffraction efficiency on the incident angle of the reproduction light are multiplexed in one hologram layer. Display device. 47. The image display device according to claim 24, wherein the polarization-selective hologram optical element and the reflection-type spatial light modulation element are optically adhered and integrally formed. 48. The reflection-type spatial light modulation element has a rectangular shape, and a long side direction thereof coincides with an incident direction of illumination light to the polarization-selective hologram optical element. 25. The image display device according to 24. 49. A light source that emits illumination light, and an isotropic region having a refractive index isotropic property and an anisotropic region having a refractive index anisotropy are alternately provided between two optical substrates. A transmission-type polarization-selective hologram optical element configured to be laminated in a direction along a main surface of the optical element and diffracting incident illumination light; and a polarization state of the illumination light diffracted by the polarization-selective hologram optical element is modulated. Transmissive spatial light modulator for transmitting the illumination light to the polarization selective hologram optical element, and projection for projecting the illumination light modulated by the transmissive spatial light modulator onto a screen An illumination system, wherein the illumination optical system emits illumination light emitted from the light source at an incident angle of 30 ° or more and less than 90 ° with respect to a normal to an illumination light receiving surface of the polarization selective hologram optical element. Incident In the selective hologram optical element, an optical axis of the anisotropic region is substantially parallel to a light receiving surface of the polarization selective hologram optical element, and a boundary between the anisotropic region and the isotropic region. An image display device, which is oriented so as to be substantially parallel to a surface, and mainly diffracts an S-polarized component of the illumination light toward the transmission-type spatial light modulator. 50. The image display device according to claim 49, wherein the isotropic region is mainly composed of a photopolymerizable polymer material or a thermopolymerizable polymer material. 51. The image display device according to claim 49, wherein the anisotropic region contains a liquid crystal material. 52. The image display device according to claim 51, wherein the alignment of the liquid crystal material is controlled by alignment control means. 53. An alignment control means for a liquid crystal material, comprising: an alignment film provided on an optical substrate, an electric field or a magnetic field applied to the polarization selective hologram optical element, or
53. The image display device according to claim 52, wherein any one of the light beams applied to the polarization selective hologram optical element or a combination thereof is used. 54. The liquid crystal material is a photocurable liquid crystal,
52. The liquid crystal composition is cured by being irradiated with a light beam having a wavelength for curing the photocurable liquid crystal, the orientation of which is controlled by the alignment regulating means in an uncured state.
The image display device as described in the above. 55. An alignment control means for a liquid crystal material, comprising: an alignment film provided on an optical substrate; or an electric or magnetic field applied to the polarization selective hologram optical element;
55. The image display device according to claim 54, wherein any one of the light beams applied to the polarization selective hologram optical element or a combination thereof is used. 56. Two optical substrates each having a transparent electrode,
50. The image display device according to claim 49, wherein the azimuth of the optical axis of the anisotropic substance is variably controlled by an electric field generated by the voltage applied to the transparent electrode. 57. A light source having a rectangular light-emitting portion, wherein a short side direction of the light-emitting portion is made to coincide with an incident direction of illumination light to the polarization-selective hologram optical element. 50. The image display device according to claim 49. 58. An illumination optical system comprising: a polarization conversion means for rotating a polarization direction by 90 ° of a component of the illumination light having a polarization direction orthogonal to the polarization direction at which the diffraction efficiency of the polarization selective hologram optical element is maximized. 50. The image display device according to claim 49, further comprising: 59. The illumination optical system further comprises a polarization selection unit for selectively transmitting a component having a polarization orientation that maximizes the diffraction efficiency of the polarization-selective hologram optical element in the illumination light. 50. The image display device according to claim 49. 60. The light source or the illumination optical system further comprises a time-sequential wavelength band switching means for sequentially transmitting only a plurality of specific wavelength bands in the entire wavelength band of the illumination light sequentially. 50. The image display device according to claim 49. 61. The image display device according to claim 49, wherein the illumination optical system includes a correction polarization selective hologram optical element having a bend angle of the opposite sign to that of the polarization selective hologram optical element. 62. The image display device according to claim 49, wherein the polarization selective hologram optical element for correction is the same element as the polarization selective hologram optical element. 63. A coupling prism having an optical surface that is in close contact with the polarization-selective hologram optical element and has a first optical surface on which at least illumination light is incident substantially perpendicularly, 50. The image display device according to claim 49, wherein the illumination light is incident at an incident angle of 60 [deg.] Or more and less than 90 [deg.] With respect to a normal to the illumination light receiving surface. 64. The image according to claim 49, wherein a bend angle, which is a difference between an incident angle of the illumination light and an exit angle of the diffracted light with respect to the hologram surface of the polarization selective hologram optical element, is 30 ° or more. Display device. 65. The image display device according to claim 49, wherein the polarization-selective hologram optical element is constituted by a plurality of hologram layers having different wavelength dependences of diffraction efficiency. 66. The image display apparatus according to claim 49, wherein the polarization-selective hologram optical element is constituted by a plurality of hologram layers having different diffraction light dependences on the incident angle of the reproduction light. 67. The image display device according to claim 49, wherein the polarization-selective hologram optical element has a plurality of holograms having different diffraction efficiency wavelength dependences multiplexed in one hologram layer. 68. The image according to claim 49, wherein the polarization-selective hologram optical element is configured such that a plurality of holograms having different diffraction efficiency dependences on the incident angle of the reproduction light are multiplexed in one hologram layer. Display device. 69. The image display device according to claim 49, wherein the polarization-selective hologram optical element and the transmission-type spatial light modulation element are optically adhered and integrally formed. 70. A light source for emitting illumination light, and an isotropic region having a refractive index isotropic property and an anisotropic region having a refractive index anisotropy between two optical substrates are alternately provided on the optical substrate. A transmission-type polarization-selective hologram optical element configured to be laminated in a direction along a main surface of the optical element and diffracting incident illumination light; and a polarization state of the illumination light diffracted by the polarization-selective hologram optical element is modulated. A reflective spatial light modulating element that reflects the reflected light, an illumination optical system that guides the illumination light to the polarization-selective hologram optical element, and an illumination light that is modulated by the reflective spatial light modulation element to an observer's pupil A virtual image observation optical system, wherein the illumination optical system converts the illumination light emitted from the light source into an incident angle of 30 ° or more and less than 90 ° with respect to a normal to an illumination light receiving surface of the polarization selective hologram optical element. And select the above polarization The optical axis of the anisotropic region is substantially parallel to the light-receiving surface of the polarization-selective hologram optical element, and a boundary surface between the anisotropic region and the isotropic region. The illumination light is oriented substantially parallel to the light, and mainly diffracts the S-polarized light component of the illumination light toward the reflective spatial light modulator, and is modulated by the reflective spatial light modulator and re- P of incident illumination light
An image display device characterized by transmitting 70% or more of the P-polarized light component when the diffraction efficiency for the polarized light component is 10% or less. 71. The image display device according to claim 70, wherein the isotropic region is mainly composed of a photopolymerizable polymer material or a thermopolymerizable polymer material. 72. The image display device according to claim 70, wherein the anisotropic region contains a liquid crystal material. 73. The image display device according to claim 72, wherein the alignment of the liquid crystal material is controlled by an alignment control unit. 74. An alignment control means for a liquid crystal material, comprising: an alignment film provided on an optical substrate; or an electric or magnetic field applied to the polarization selective hologram optical element;
74. The image display device according to claim 73, wherein any one of the light beams emitted to the polarization selective hologram optical element or a combination thereof is used. 75. The liquid crystal material is a photocurable liquid crystal,
73. The liquid crystal composition is cured by being irradiated with a light beam having a wavelength for curing the photocurable liquid crystal, the orientation of which is controlled by the alignment regulating means in an uncured state.
The image display device as described in the above. 76. An alignment control means for a liquid crystal material, comprising: an alignment film provided on an optical substrate; or an electric or magnetic field applied to the polarization-selective hologram optical element;
76. The image display device according to claim 75, wherein any one of the light beams applied to the polarization selective hologram optical element or a combination thereof is used. 77. The two optical substrates have transparent electrodes,
71. The image display device according to claim 70, wherein the azimuth of the optical axis of the anisotropic substance is variably controlled by an electric field generated by an applied voltage to the transparent electrode. 78. The light source has a rectangular light-emitting portion, and the short side direction of the light-emitting portion is made to coincide with the incident direction of illumination light to the polarization-selective hologram optical element. The image display device according to claim 70. 79. An illumination optical system comprising: a polarization conversion means for rotating a polarization direction by 90 ° of a component of the illumination light having a polarization direction orthogonal to the polarization direction at which the diffraction efficiency of the polarization selective hologram optical element is maximized. 71. The image display device according to claim 70, further comprising: 80. The illumination optical system includes a polarization selection unit that selectively transmits a component having a polarization orientation that maximizes the diffraction efficiency of the polarization selective hologram optical element in the illumination light. 71. The image display device according to claim 70. 81. The light source or the illumination optical system further comprises a time-sequential wavelength band switching means for temporally sequentially transmitting only a plurality of specific wavelength bands in the entire wavelength band of the illumination light. 71. The image display device according to claim 70. 82. The image display apparatus according to claim 70, wherein the illumination optical system includes a polarization-selective hologram optical element for correction having a bend angle opposite to that of the polarization-selective hologram optical element. 83. The image display device according to claim 70, wherein the polarization selective hologram optical element for correction is the same element as the polarization selective hologram optical element. 84. A first optical surface which optically adheres to the polarization selective hologram optical element and at least illumination light is incident substantially perpendicularly, and light reflected by the reflection type spatial light modulator is emitted substantially perpendicularly. And a coupling prism having a second optical surface. The polarization-selective hologram optical element receives illumination light at an incident angle of 60 ° or more and less than 90 ° with respect to a normal to the illumination light receiving surface. 71. The image display device according to claim 70, wherein: 85. The coupling prism has a third optical surface provided with a light absorption layer on which specular reflection light of illumination light from the reflection type spatial light modulation element is incident substantially perpendicularly. The image display device according to claim 84, wherein: 86. A projection optical system, comprising: a polarization selecting means for selectively transmitting a component of a polarization direction transmitted through the polarization-selective hologram optical element, of the light modulated by the reflection-type spatial light modulation element. 71. The image display device according to claim 70, wherein: 87. The image according to claim 70, wherein a bend angle, which is a difference between an incident angle of the illumination light and an exit angle of the diffracted light with respect to the hologram surface of the polarization selective hologram optical element, is 30 ° or more. Display device. 88. The image display according to claim 70, wherein the hologram surface of the polarization-selective hologram optical element and the reflection surface of the reflective spatial light modulator have an optically inclined positional relationship. apparatus. 89. The image display apparatus according to claim 70, wherein the polarization-selective hologram optical element is constituted by a plurality of hologram layers having different wavelength dependences of diffraction efficiency. 90. The image display apparatus according to claim 70, wherein the polarization-selective hologram optical element is constituted by a plurality of hologram layers having different diffraction light dependences on the incident angle of the reproduction light. 91. The image display device according to claim 70, wherein the polarization-selective hologram optical element has a plurality of holograms having different diffraction efficiency wavelength dependences multiplexed on one hologram layer. 92. The image according to claim 70, wherein the polarization-selective hologram optical element has a plurality of holograms having different diffraction efficiencies depending on a reconstructed light incident angle, which are multiplexed in one hologram layer. Display device. 93. The image display device according to claim 70, wherein the polarization-selective hologram optical element and the reflection-type spatial light modulation element are optically adhered and integrally formed. 94. The reflection-type spatial light modulator has a rectangular shape, and a long side direction thereof coincides with an incident direction of illumination light to the polarization selective hologram optical element. 70. The image display device according to 70.