JP3315433B2 - Volume hologram optical film, liquid crystal optical element and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a volume hologram optical film, a liquid crystal optical element, and a method for producing the same using a liquid crystal cured product composite comprising a liquid crystal and a cured product .

[0002]

2. Description of the Related Art As a volume hologram optical film, a film in which layers having different refractive indices are laminated in a resin film is known (conventional example 1) . This, for example, the photocurable compound by applying a light beam was Tsu assortment from two directions phase, causing interference, different layers of refractive index in layers is produced so as to be laminated.

This volume hologram optical film selectively transmits or selectively reflects a specific wavelength determined by its pitch (the interval between a high refractive index portion and an adjacent high refractive index portion). For this reason, its use in head-up displays, high-mount stop lamps, three-dimensional three-dimensional displays, and the like is being studied. Also, US Pat.
No. 38568 (conventional example 2) discloses that liquid crystal bubbles having different diameters are used.
Using a resin to diffract light in the off state
Indicated. International Publication No. 91-10926 is also known.
(Conventional example 3).

[0004]

However, the volume hologram optical film can always display only a fixed display, and it has been desired to change the display. For this reason,
It has also been proposed to form a porous volume hologram optical film by a conventional manufacturing method and impregnate it with liquid crystal, but the production is troublesome, the refractive index difference cannot be taken so much, and the productivity is not good. There was a point.

[0005] In the photocurable compound used in the volume hologram optical film, by applying a light beam was Tsu assortment from two directions phase, uncured product of the photocurable compound using interference of those two beams However, there is also a problem that even if it is cured into a layer, only a slight difference in refractive index is exhibited . For this reason, when used as a volume hologram, the diffraction efficiency of light is poor and the number of layers must be increased, and it has been desired to improve the diffraction efficiency.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems .

[0007] mixture containing a photocurable uncured material and the liquid crystal, by applying a light beam aligned in two directions phases, their 2
A step of curing a photocurable uncured material into a layer by using the interference of two light beams, and a step of completing the entire curing, and then applying an external field only in one of the two steps. By applying different external fields in the above, a layer structure composed of a liquid crystal and a cured product is formed, the refractive index of the layer structure changes periodically, and the pitch p of the change is 50 nm ≦ p ≦ 50.
A method for producing a volume hologram optical film having a relationship of 0 nm, wherein the layer structure is formed along the surface direction of the film.

Furthermore, as its liquid crystal optical active element substrate and one substrate was placed an active element for each pixel of the device, to provide a liquid crystal optical element that displays an image.

[0009] In a volume hologram optical film comprising a liquid crystal and cured product of the present invention, the inside in a particular liquid crystal alignment state I along the direction of the film has a periodically varying layer structure. The difference in the alignment state of the liquid crystal becomes the difference in the refractive index.

Layer of Volume Hologram Optical Film of the Invention
The structure is formed along the plane direction, and the layers having different refractive indices cause an interference effect to act as a volume hologram optical film. This is different from Conventional Example 2.

FIG. 1 is a sectional view of an example of the volume hologram optical film of the present invention. In FIG. 1, reference numeral 1 denotes a volume hologram optical film, which has a liquid crystal alignment state .
Higher layers 1A refractive index of, 1C, 1E, and 1G · · ·,
A low refractive index layer 1B having a different orientation state,
1D, 1F,... Are stacked. To Ku Ease Ri <br/> or I in this figure, although the high refractive index layer and the low refractive index layer is represented in a state of complete separation, usually gradually refractive index changes ing. That is, the alignment state of the liquid crystal is gradually changing.

The high refractive index layer and the low refractive index layer combine to form one pitch (p). Specifically, one pitch (p) is formed between the high refractive index layer 1A and the high refractive index layer 1C adjacent to the low refractive index layer 1B.

Specifically, there is a layer having two orientation states inside the film. The alignment state of the liquid crystal is different between the one layer and the other layer, and this is repeated periodically, and a large number of layers are stacked. More specifically, even though the liquid crystal exhibits ordered orientation from the microscopic viewpoint, the liquid crystal is almost aligned randomly in the macroscopic orientation, and is almost parallel to a specific direction. There is an alignment state close to. Note that both layers are oriented in a specific direction,
This particular direction may be different in both layers. The difference in the orientation of the liquid crystal causes a difference in the refractive index.

In this case, even if the liquid crystal content is the same in both layers, the refractive index is different, so that the liquid crystal content does not necessarily have to be different in both layers. Needless to say, the content of the liquid crystal may be made different between the two layers to further increase the difference in the refractive index.

According to the present invention, by employing the above-described structure, a difference in refractive index is increased to improve diffraction efficiency, and display information and wavelength dependency are changed by an external electric field, magnetic field, or the like. be able to. According to the production method of the present invention, a special material such as that used for a normal volume hologram is not required, and after curing, a specific material is removed,
Since there is no need to impregnate other materials as in the conventional example 3 , the productivity is good.

Compared with Conventional Example 1 , the volume hologram optical film of the present invention is composed of a cured product and a liquid crystal, and utilizes the difference in the refractive index caused by the difference in the orientation of the liquid crystal.
The difference in refractive index between layers can be increased. Further, by applying a field, the refractive index of the liquid crystal portion can be changed, and the display information and the wavelength dependency can be changed. Also,
The change pitch p has a relationship of 50 nm ≦ p ≦ 500 nm.
And the layer structure is formed along the surface direction of the film.
I have.

In the present invention, diffraction is performed by layers having different refractive indexes. In this case, which wavelength light is to be subjected to diffraction is determined by the refractive index of the material of the film and the pitch of the layer structure. For example, if the refractive index is used of about 1.5 of the resin material from ultraviolet wavelength of about 300 nm, about 1500n
between to the near infrared wavelength of m, in order to express the diffraction effects, provided 5 0 to 500 nm of about pitch p of the layer structure
You . It is also conceivable to use higher order diffraction. Thus, (the distance between the high layer of refractive index and the adjacent high refractive index layer) the pitch p of the layer structure, and 5 0 to 500 nm approximately
I do .

If it is desired to diffract only light of a specific wavelength, the pitch may be kept constant. Thus, only a specific wavelength can be transmitted or reflected. If an external field is applied to this, transmission of a specific wavelength can be turned on / off or reflection can be turned on / off depending on the field. In this application, color display can be performed without providing a coloring layer. For example, RGB 3
By forming a volume hologram optical film corresponding to a color for each pixel electrode, color display can be performed without a color filter.

Further, when it is desired to diffract light in a wavelength range of a certain range may be changed to suit the pitch range of the wavelength range. Thereby, a specific wavelength range can be transmitted or reflected. If the application of an external field is used together with this, transmission in a specific wavelength range can be turned on / off or reflection can be turned on / off depending on the field. In this application, a dimming window that reflects the infrared rays of the sun in summer and transmits the infrared rays of the sun in winter can be used.

In the present invention, the refractive index of the liquid crystal alignment state is provided me by the <br/> different different layers are stacked. This difference in refractive index is ideally the refractive index n ₁ between the two layers. Is n
_Two However, in an actual volume hologram optical film, the refractive index usually gradually changes. Therefore, the maximum value in the high refractive index layer is n ₁ , and the minimum value in the low refractive index layer is n ₂ And the refractive index difference Δn is Δn = n ₁ −n ₂ Expressed by In the present invention, the refractive index difference Δn, since related to the half-width of the diffraction efficiency and the diffraction light may larger, for example, the refractive index difference between the layers 0.
02 or more, preferably 0.05 or more.

The number of the layers is determined by the desired diffraction efficiency, but is about 10 to 100 in pitch (one layer of a layer having a high refractive index and a layer of a low refractive index is set as one pitch). When the refractive index difference Δn is about 0.2, the diffraction efficiency exceeds about 90% by stacking 30 pitches. When the refractive index difference Δn is about 0.1, it is necessary to stack about 60 pitches to obtain the same diffraction efficiency.

In the present invention, the layer structure has a structure along the film surface.
It is formed in the lateral direction. Layer structure of its is parallel to the film plane
Or , formed at a specific angle to the film surface
You . When it is almost parallel to the film surface, it becomes a reflection type volume hologram.

For example, when light is incident on the volume hologram optical film of FIG. 1 from an obliquely upper side 2A, light of a specific wavelength determined by the pitch and the refractive index is reflected on the opposite obliquely upper side 2B. Therefore, it is used for head-up displays, high-mount stop lamps, infrared reflection windows, and the like.

As a reference example, a volume hologram optical film having different layer directions will be described . This is layer 1 on the film surface
A to 1G are arranged vertically . And light of a specific wavelength is 2
Missing from A to the lower direction in the figure, it becomes Rukoto be transmitted through the film surface. For this reason, it is possible to use a color display without using a color filter.

The cured product of the present invention can be mixed with the liquid crystal in an uncured state, and is preferably a homogeneous solution. In general, the photo-curable resin material is used, if <br/> photocurable ones can be used with silicon or non-machine materials such as titanium, in combination with the heating step as needed also not good. It is preferable that the mixture be a homogeneous solution because it can be easily handled. The important point here is that in the present invention, the photo-curable material may be an ordinary photo-curable material, and does not require a special material as used for an ordinary volume hologram.

The liquid crystal of the present invention may be a nematic liquid crystal or a smectic liquid crystal.
Chi Tsu available click liquid crystal or the like can be used in a liquid crystal having a different refractive index in a different orientation states. Usually, several kinds of liquid crystal materials and non-liquid crystal materials having a liquid crystal-like structure are mixed to obtain desired refractive index anisotropy, dielectric anisotropy, temperature range showing liquid crystallinity, threshold voltage, and the like. Used as a composition.

[0027] When it is sandwiched between the substrate with the electrodes for applying the electric field, in particular, a combination of a nematic liquid crystal and a photocurable resin material (monomer, oligomer) having a positive dielectric anisotropy is preferable . And the photocurable resin material
Refractive index of the cured product fee is formed by curing (n _P ) Is the ordinary light refractive index ( n ₀ ) of the liquid crystal used. ) Or the extraordinary refractive index (n
_e ) Is preferably made to substantially coincide with the above. In particular, the ordinary refractive index of the liquid crystal ( n ₀ ) Is preferably made to substantially coincide with the above.

When no electric field is applied, the refractive index of the cured product in the resin matrix is different from the refractive index of at least a part of the liquid crystal. occurs, the reflective or transmissive occurs. Conversely, when an electric field is applied, the refractive index of the cured product matches the refractive index of the entire liquid crystal, the hologram property is lost, and light is transmitted as it is. n _P = N ₀ Accordingly, the liquid crystal when an electric field is applied is completely aligned in one direction when a sufficiently high electric field is applied, so that the transmittance is extremely high.

[0029] In addition, the outside of the photo-curable material, other monomers such as for adjusting the refractive index, oligomers, may be used in combination polymers. This is because light curing must be performed in the first curing step, but heat curing may be performed in the entire curing step. It is preferable that these materials also have compatibility. Furthermore, a viscosity modifier, a coloring agent,
An additive such as a coloring dye may be added.

The manufacturing method of the present invention will be described. In the present invention, As a first step, the mixture comprising the photocurable uncured material and the liquid crystal, by applying a light beam was Tsu assortment from two directions phases, by utilizing the interference of those two beams The photocurable uncured material is cured into a layer. Then, as a second step,
Irradiating light or heating to complete the entire curing.

During any of these steps, an external field such as an electric field, a magnetic field, or a tensile force for orienting the liquid crystal in a specific direction is applied. Of course, an external field that produces different orientations may be applied to both steps. This makes it possible to manufacture a volume hologram optical film including a liquid crystal and a cured product and having a layered structure in which the refractive index periodically changes. In this case, the amount of light at the time of photocuring in the first step should be large so that the liquid crystal and the cured product do not separate into particles that cause clear scattering.

[0032] In this case, when irradiated with light was Tsu assortment of phase two directions of 2A and 2D 1, can form a different layer structure refractive index due to a difference in Do orientation state will Yo in Figure 1. If you want to shift this layered structure 90 degrees in the vertical direction,
Light may be irradiated from two directions A and 2C (reference example) .
As for the method of supplying the light was Tsu assortment of this phase, for example, a laser beam of single mode may be used as parallel light that has spread using a beam expander.

When curing is performed without applying an external field, a cured product is formed. In a layer where a large amount of liquid crystal exists, the liquid crystal molecules are oriented in a substantially random direction when viewed macroscopically.

On the other hand, if the curing is performed while applying an external field, the liquid crystal molecules tend to be oriented in a specific direction, although the reason is not clear. This is because the cured product is affected by the liquid crystal molecules forcibly aligned by the external field and tries to maintain the same alignment even after removing the external field, or the formed cured product changes its shape It seems to be caused. Normally, an external field may be applied only during one step, but different external fields may be applied to both of the two steps to obtain different alignment states.

The degree to which the alignment state of the liquid crystal is fixed can be controlled by the crosslinking density in the cured product, the contact energy of the cured product with the liquid crystal, and the like. Was but I, in a mixture of uncured before curing, or light-curable polyfunctional compounds, different crystal and polarity is introduced to the curable compound having for example, a hydroxyl group, the control of delicate state Will be possible. As the polyfunctional compound, a monomer or oligomer having 2 to 6 functions is used. Further, among these, it introduces a polymer having no functional group, such as polarity is also utilizing the characteristics
Can Ru.

In the present invention, it is preferable that the photocurable uncured material and the liquid crystal form a homogeneous solution. According to this method,
A homogeneous volume hologram optical film is easily obtained.

For example, a photocurable compound and a positive dielectricrateAnisotropic
Nematic liquid crystal having the property that the ordinary refractive index of the liquid crystal
(n _O ) And the refractive index of the cured product of the photocurable compound (n _P )But
n _O ≒n _P Is used. This has two lights
In the area where light is applied most strongly by irradiating a line,
The curing compound is almost cured. At this time, apply an electric field
Then, the liquid crystal molecules are aligned in a direction parallel to the electric field. this part
Liquid crystal molecules remain in the same state even after the electric field is removed after curing
The orientation tends to continue in a state close to. That is, in FIG.
If an electric field is applied vertically to cure the liquid crystal molecules,
It is oriented vertically (vertically).

Next, the whole is irradiated with light or heated to complete the curing. In this case, it is not necessary to apply an electric field. It is preferred that this polymerization be carried out very slowly and that scattering in the cured layer be minimized. In this case, the liquid crystal molecules are oriented by the influence of the cured product, but when viewed macroscopically, they are nearly random. However, at this time, a weak electric field may be applied to adjust the refractive index, or a magnetic field may be applied in the horizontal direction to align the liquid crystal molecules in the horizontal direction. For this reason, all layers cured after this
When viewed as a body, the refractive index of the liquid crystal is different from n _O, and when combined with the refractive index of the cured product, the liquid crystal shows a different refractive index from the layer cured in the previous step.

As a result, a difference in refractive index occurs between the layers, and functions as a hologram. When this is sandwiched between substrates with electrodes and an electric field is applied, the liquid crystal of the layer which is oriented in a state close to random (other than vertical) is also vertically oriented, and the refractive index is n _O. Becomes Therefore, the refractive index of the entire film becomes the same, that is, the same as a homogeneous transparent body,
The hologram property disappears. By using this, the characteristics of the hologram can be turned on / off by an electric field, and color display and infrared reflection performance can be switched.

The application of the electric field in the curing step is reversed, and light is applied from two directions to cure without applying an electric field first.
In the second step, an electric field may be applied for curing. Also,
Instead of an electric field, a magnetic field can be used as another external field that can align the liquid crystal, or a tensile force can be used. However, the application of an electric field is the simplest and the productivity is good. In particular, in the case of sandwiching and using between substrates with electrodes, it is only necessary to sandwich and cure between them from the beginning, so that productivity is extremely high.

In two steps, an external field can be applied from two different directions to change the alignment direction of the liquid crystal in each layer.

Further, by partially applying an external field or partially performing the first step, it is possible to partially impart hologram properties without making the entire hologram the same.
Also, the hologram characteristics can be partially changed by partially changing the irradiation laser wavelength or the intensity or direction of the external field.

The refractive index difference between the layers can be set to a desired value by appropriately selecting the difference in the refractive index depending on the alignment state of the liquid crystal, the irradiation time of the two rays, the standing time, the average content of the liquid crystal, and the like. . In the present invention, it is preferable that the liquid crystal swells in the matrix of the cured product and is in a uniform state, but is not clearly separated such that scattering does not occur in a visible light region or a near infrared light region. It may be in a state.

According to the present invention, the hologram property can be turned on / off by an electric field. For example, only the transmission of near-infrared rays can be controlled depending on the presence or absence of an electric field, and visible light can always be transmitted. Thus, the window can be used as a window that reflects near-infrared rays in summer and transmits an near-infrared ray by applying an electric field in winter.

FIG. 2 is a front view of a liquid crystal optical element in which the volume hologram optical film of the present invention is sandwiched between substrates with electrodes. In FIG. 2, the volume hologram optical film 1
Is sandwiched between a substrate 4A provided with an electrode 3A and a substrate 4B provided with an electrode 3B. Although not shown in this figure, a seal may be formed at the end of the volume hologram optical film 1.

By applying an electric field between the upper and lower electrodes 3A and 3B, the orientation of the liquid crystal changes, and the refractive index changes. Specifically using a nematic liquid crystal having positive dielectric anisotropy, n _O of the refractive index and the liquid crystal of the cured product This will be described based on an example in which a material having substantially the same value is used. First, the volume hologram optical film itself is also manufactured by sandwiching a homogeneous solution of a photocurable compound and a liquid crystal between the substrates with the electrodes and curing. As in the above example, it is assumed that an electric field is applied when light is applied from two directions, which is the first step, and curing is performed. In the second overall curing, curing is performed without applying an electric field.

The liquid crystal optical element sandwiching the volume hologram optical film reflects light of a specific wavelength, for example, blue light in a state where nothing is done due to the hologram characteristics due to the difference in the alignment state of the liquid crystal. In this state, when an electric field is applied between the two electrodes and the liquid crystal molecules are almost vertically oriented, the refractive index of the cured product and the ordinary light refractive index of the liquid crystal match over the entire film, and the volume hologram optical film is simply uniform. It becomes a film having a refractive index. In this state, since all light is transmitted, blue light is not reflected.

It is assumed that the layer structure of the volume hologram optical film of FIG. 1 is sandwiched between the substrates with electrodes of FIG. 2 in a state where the layer structure is shifted by 90 ° (the layer is perpendicular to the substrate surface). It is assumed that blue light is transmitted in this state. In this state, when an electric field is applied between the two electrodes and the liquid crystal molecules are almost vertically oriented, the refractive index of the cured product matches the ordinary refractive index of the liquid crystal, and the volume hologram optical film has a mere uniform refractive index. It becomes a film. In this state, all light is transmitted.

As the photocurable compound of the present invention, a photocurable resin is generally used as described above. In particular, a vinyl photocurable compound is preferable, and an acrylic photocurable compound is particularly preferable. Optimal.

As the substrate with electrodes, ITO ( In ₂ O ₃
-SnO ₂ ), SnO ₂ For example, a transparent substrate such as glass or plastic with a transparent electrode can be used. Of course, it can be a substrate on which opaque electrodes such as metal wires are formed,
An active matrix substrate provided with an active element such as a thin film transistor (TFT), a thin film diode, a metal insulator, and a metal non-linear resistance element (MIM) may be provided for each pixel electrode. Further, in applications such as mirrors, one electrode may be a reflective electrode, and the substrate may be an opaque substrate.

The volume hologram optical film of the present invention comprises:
As described above, it can be used for the same applications as conventional volume hologram optical films. Specifically, there are a head-up display, a high mount stop lamp, an infrared reflection window, a three-dimensional three-dimensional display, and the like. In addition, it may be used by attaching it to a glass surface such as a window or a plastic surface, or may be used by being enclosed in laminated glass or laminated glass.

The present invention has a great advantage that the hologram characteristics can be changed by using the liquid crystal optical element by applying an electric field. For this purpose, it is used by sandwiching it between substrates with electrodes. As a manufacturing method for this, there is the following manufacturing method.

First, there is a method in which a mixture containing a photocurable uncured material and a liquid crystal is sandwiched between substrates with electrodes and irradiated with light to cure the mixture. More specifically, there is a method in which a substrate with electrodes is sealed around the periphery to form a cell, and a mixture containing a photocurable uncured material and a liquid crystal is injected into the cell and sandwiched and cured. is there. This is effective mainly for small display device-like applications. When an electric field is used as an external field at the time of curing, the electrode on the substrate can be used.

There is also a method in which a mixture containing a photocurable uncured substance and a liquid crystal is supplied onto a substrate with electrodes, and then another substrate with electrodes is overlaid, and then cured by applying a light beam. This is effective mainly for large-area applications such as windows.
In any of these methods, since the material is cured while being sandwiched between substrates, it is necessary to use a material that does not generate by-products such as gas during curing. Also, according to this method, the film thickness
It is uniformly formed easily benefits. Also in this case, when an electric field is used as an external field at the time of curing, the electrode of this substrate can be used.

A second method is to supply a mixture containing an uncured photocurable substance and liquid crystal onto a substrate with electrodes, apply a light beam, cure the mixture, and then stack another substrate with electrodes. is there. According to this method, even if a by-product such as gas is generated at the time of curing, it can be used. However, adverse effects may occur when the by-products are separated, and in this case, it is preferable to use a material that does not generate by-products. In this case, if an electric field is used at the time of curing, a separate electrode must be used. Therefore, there is little merit unless a magnetic field is used.

Third, a mixture containing a photocurable uncured material and a liquid crystal is irradiated with a light beam and cured to produce a volume hologram optical film. Thereafter, electrodes are provided on both sides of the volume hologram optical film. There is a method of stacking the substrates. This has almost the same effect as the second manufacturing method ,
The two electrode substrate with no so as to completely bonded if that can not be be Nau well rows off. Also in this case, when an electric field is used at the time of curing, a separate electrode must be used. Therefore, there is little merit unless a magnetic field is used.

The liquid crystal optical element of the present invention can be used for a light control window, a display element and the like. In addition, a backlight, a lens, a prism, a mirror, a diffusion plate, a light absorber, a color filter, an ultraviolet cut filter, and the like may be used in combination with the liquid crystal optical element.

[0058]

EXAMPLES Example 1 and Example 1A A nematic liquid crystal having a positive dielectric anisotropy having a refractive index anisotropy of 0.26, an acrylic photocurable compound, a photoreaction initiator, and a sensitizing dye were mixed. An uncured solution was obtained. Note that n of the liquid crystal
_O And the cured resin of the acrylic photocurable compound had substantially the same refractive index. This solution was cast on a glass plate.

[0059] using an argon laser (wavelength 514.5 nm) as an exposure light source, and collimated by the beam expander, after the two light beams using a mirror parallel rays of this, the two directions of the 2A and 2D 1 From the solution layer cast on a glass plate. At that time, a magnetic field was applied between the upper and lower sides to cure. Thereafter, the magnetic field was removed and the whole was exposed to ultraviolet rays to complete the curing, thereby producing a volume hologram optical film. Further, in Example 1A, the volume hologram optical film in the same manner except that no magnetic field is applied (Embodiment
Example 1A ) was prepared.

Each of the volume hologram optical films of Example 1 and Example 1A had green reflection, and a spectroscopic measurement showed a reflection band near 540 nm. Hologram optical film is more effective
The scattering property was smaller and the diffraction efficiency was better than the volume hologram optical film of Example 1A .

Example 2 The solution of Example 1 was injected into a cell formed by using a glass substrate with an ITO electrode, and exposed by the same method. However, instead of applying the magnetic field in the first step, an electric field was applied between the upper and lower electrodes to cure the electrode. This cell had a green reflection similarly to Example 1, and a spectroscopic measurement showed a reflection band around 540 nm. When an electric field was applied between the electrodes, the green reflection was reduced. Also in the case of this example, scattering was smaller and diffraction efficiency was better than that manufactured without applying an electric field.

Example 3 The solution of Example 1 was cast on a plastic film substrate with an ITO electrode, and another plastic film substrate with an ITO electrode was overlaid thereon. Exposed. This liquid crystal optical element has green reflection in the same manner as in Example 2.
A reflection band was observed around 540 nm, and when an electric field was applied between the electrodes, green reflection was reduced.

Example 4 A plastic film substrate with an ITO electrode was superimposed on both sides of the volume hologram optical film produced in Example 1. This liquid crystal optical element has green reflection as in the case of the third embodiment.
A reflection band was observed in the vicinity, and when an electric field was applied between the electrodes, green reflection was reduced.

[0064]

According to the volume hologram optical film of the present invention, it is easy to increase the refractive index difference between the layers, and it is easy to obtain a volume hologram optical film having a high diffraction efficiency with a small number of layers. There is also an advantage that a usual photocurable compound can be used as a photocurable uncured product to be used.

By using this volume hologram optical film as a liquid crystal optical element sandwiched between substrates with electrodes, reflection and transmission of light of a specific wavelength can be controlled by turning on and off the electric field. Thereby, it can be used for a light control window, a color display element, and the like. In particular, color display can be performed without a color filter.

[0066] or in parallel direction of the layer of the volume hologram optical film the film surface or by Oh Ru angle inclined, the volume hologram optical film of various characteristics can be easily obtained.

The present invention can be applied to various applications within a range that does not impair the effects of the present invention.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view for explaining the concept of a volume hologram optical film of the present invention.

FIG. 2 is a front view of a liquid crystal optical element using the volume hologram optical film of the present invention.

[Explanation of symbols]

 1: Volume hologram optical film 2A, 2B, 2C, 2D: Light direction 3A, 3B: Electrode 4A, 4B: Substrate

──────────────────────────────────────────────────続 き Continued on the front page Examiner Toshimitsu Satomura (56) References JP-A-63-4205 (JP, A) JP-A-4-355424 (JP, A) JP-A-5-80310 (JP, A) Kaihei 5-72509 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02B 5/32 G03H 1/00-1/30 G02F 1/13

Claims (5)

(57) [Claims] To 1. A photocurable of uncured material with a mixture containing a liquid crystal, by applying a light beam was Tsu assortment from two directions phases, their 2
A step of curing a photocurable uncured material into a layer by using the interference of two light beams, and a step of completing the entire curing, and then applying an external field only in one of the two steps. By applying different external fields in the above, a layer structure composed of a liquid crystal and a cured product is formed, the refractive index of the layer structure changes periodically, and the pitch p of the change is 50 nm ≦ p ≦ 50.
A method for producing a volume hologram optical film having a relationship of 0 nm, wherein the layer structure is formed along the surface direction of the film. 2. A volume hologram optical filter according to claim 1,
Volume hologram optical filter
Lum. 3. A method for manufacturing a liquid crystal optical element, comprising arranging a volume hologram optical film between substrates with electrodes using the manufacturing method according to claim 1, comprising the following steps (1), (2) and (2). A method for producing a liquid crystal optical element, comprising the step of 3). (1) a step of manufacturing the volume hologram optical film by sandwiching the mixture between substrates with electrodes; (2) manufacturing the volume hologram optical film after mounting the mixture on the substrate with electrodes; (3) a step of stacking and integrating substrates with electrodes on both sides of the volume hologram optical film; 4. A method for manufacturing a liquid crystal optical element according to claim 3.
Liquid crystal optical element manufactured by the company. 5. A light control element or a display element.
5. The liquid crystal optical element according to 4.