JP2017015897A - Image projection system and projection surface member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image projection system that can display an image with a high contrast even in a bright environment.SOLUTION: An image projection system comprises: a projection surface member including a selective light reflection layer that can selectively reflect polarized light; a projection device that projects, to the projection surface member, first light including the polarized light that can be reflected on the selective light reflection layer and can display an image with the first light reflected on the selective light reflection layer; and a second light supply source that can illuminate the projection surface member with second light. The second light is reverse polarized light to the polarized light that is included in the first light and can be reflected on the selective light reflection layer.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image projection system and a projection surface member for the image projection system.

In the image projection system, generally, light is projected from a projection device onto a projection surface member such as a screen made of paper material or cloth material, and a desired image is displayed on the projection surface member. It has also been proposed to display an image by light transmitted through the projection surface member of the projected light (Patent Document 1). However, in an ordinary image projection system, an image is reflected by reflected light from the projection surface member of the projected light. indicate.
A technique such as that disclosed in Patent Document 2 is also known.

JP 2006-227581 A JP 2008-003536 A

  In general, in a bright environment, the contrast of an image displayed by the image projection system is low. Therefore, in order to increase the contrast in the conventional image projection system, it has been required to darken the usage environment. However, in order to darken the usage environment, it is necessary to eliminate the illumination light and the outside light. Such time and effort is complicated and may hinder the spread of the image projection system.

  The present invention has been made in view of the above problems, and an object thereof is to provide an image projection system capable of displaying an image with high contrast even in a bright environment, and a projection surface member for the image projection system.

As a result of intensive examination to solve the above problems, the inventor has obtained a projection surface member having a selective light reflective layer that can selectively reflect polarized light, and polarized light that can be reflected by the selective light reflective layer. By using an image projection system comprising a projection device that can project an image including first light and a second light source that can illuminate a projection surface member with polarized light that can pass through the selective light reflective layer, It was found that an image can be displayed with high contrast even in a bright environment, and the present invention has been completed.
That is, the present invention is as follows.

[1] a projection surface member including a selective light reflective layer capable of selectively reflecting polarized light;
Projection device capable of projecting first light including polarized light that can be reflected by the selective light reflective layer onto the projection surface member and displaying an image by the reflected light of the first light from the selective light reflective layer When,
A second light source capable of illuminating the projection surface member with a second light,
The image projection system, wherein the second light is reversely polarized with respect to polarized light that is included in the first light and can be reflected by the selective light reflective layer.
[2] The polarized light that is included in the first light and can be reflected by the selective light reflective layer is one of left circularly polarized light and right circularly polarized light,
The image projection system according to [1], wherein the second light is the other of left circularly polarized light and right circularly polarized light.
[3] The image projection system according to [1] or [2], wherein the selective light reflective layer includes a cholesteric resin layer.
[4] The image projection system according to any one of [1] to [3], wherein the projection surface member is a screen or a wall material.
[5] Any of [1] to [4], wherein the projection surface member includes the selective light reflective layer and a light absorption layer capable of absorbing the second light in this order from the side closer to the projection device. An image projection system according to claim 1.
[6] A projection surface member for receiving the first light projected from the projection device to display an image while being illuminated by the second light supplied from the second light supply source,
The projection surface member includes a selective light reflective layer capable of selectively reflecting polarized light included in the first light,
The projection surface member, wherein the polarized light that is included in the first light and can be reflected by the selective light reflective layer, and the second light are oppositely polarized light.

  According to the present invention, it is possible to provide an image projection system capable of displaying an image with high contrast even in a bright environment, and a projection surface member for the image projection system.

FIG. 1 is a schematic view schematically showing an image projection system according to the first embodiment of the present invention. FIG. 2 is a schematic diagram schematically showing the image projection system according to the first embodiment of the present invention. FIG. 3 is a schematic view schematically showing an image projection system according to the second embodiment of the present invention. FIG. 4 is a schematic view schematically showing an image projection system according to the second embodiment of the present invention.

  Hereinafter, the present invention will be described in detail with reference to embodiments and examples. However, the present invention is not limited to the following embodiments and exemplifications, and can be implemented with arbitrary modifications without departing from the scope of the claims of the present invention and the equivalents thereof.

  In the following description, unless otherwise specified, the “polarizing plate” and the “wave plate” include not only a rigid member but also a flexible member such as a resin film.

  In the following description, unless otherwise specified, “natural light” includes not only natural light such as sunlight but also artificial light that is not intended by the user, such as outdoor illumination light.

  In the following description, unless otherwise specified, retardation represents in-plane retardation. The in-plane retardation of a certain layer is a value represented by (nx−ny) × d unless otherwise specified. Here, nx represents a refractive index in a direction (in-plane direction) perpendicular to the thickness direction of the layer and giving the maximum refractive index. Ny represents the refractive index in the in-plane direction of the layer and in a direction orthogonal to the nx direction. Furthermore, d represents the thickness of the layer. In-plane retardation can be measured using a commercially available retardation measuring device (for example, “WPA-micro” manufactured by Photonic Lattice), Senarmon method, Axoscan manufactured by Axometrics, or KOBRA manufactured by Oji Scientific Instruments. At this time, the measurement wavelength is 550 nm unless otherwise specified.

  In the following description, unless stated otherwise, the term “(meth) acryl” includes both acrylic and methacrylic, the term “(meth) acrylate” includes both acrylate and methacrylate, and the term “(thio) epoxy”. "Includes both epoxy and thioepoxy, and the term" iso (thio) cyanate "includes both isocyanate and isothiocyanate.

[1. First embodiment]
FIG. 1 is a schematic view schematically showing an image projection system 10 according to the first embodiment of the present invention. As shown in FIG. 1, the image projection system 10 according to the first embodiment of the present invention includes a projection surface member 100, a projection device 200, and an illumination device 300 as a second light supply source, and natural light enters. It is installed in the room where is blocked.

Projection surface member 100 is a member for receiving the projection light L _P as a first light projected from the projection device 200 to display an image. Usually, the projection plane member 100 has a flat projection surface 100S which faces the projection apparatus 200 is provided so as to be able receive the projection light _{L P} at the projection surface 100S. In the present embodiment, an example in which a sheet-like screen having a flat projection surface 100S is used as the projection surface member 100 will be described.

FIG. 2 is a schematic diagram schematically showing the image projection system 10 according to the first embodiment of the present invention. In FIG. 2, the projection surface member 100 is shown cut along a plane perpendicular to the projection surface 100 </ b> S of the projection surface member 100. In addition, the reflection of light by the selective light reflective layer 120 can occur not only on the surface of the selective light reflective layer 120 but also inside, but as a schematic representation, in FIG. The reflection of light is illustrated as occurring on the surface of the selective light reflective layer 120.
As shown in FIG. 2, the projection surface member 100 includes a light diffusion layer 110, a selective light reflection layer 120, and a light absorption layer 130 in this order from the side closer to the projection device 200.

The light diffusion layer 110 is a layer that can diffuse and transmit light. As the light diffusion layer 110 may reflected light L _R reflected projected projection light L _P and the projection light L _P is selected light reflecting layer 120 from the projection apparatus 200, is transmitted through diffused, selected It is provided closer to the projection device 200 than the light reflective layer 120. As such a light diffusion layer 110, within the range that can maintain a high clarity of the image than the level required for the image projection system 10 may use a layer capable of diffusing the projection light L _P and the reflected light L _R.

  The specific haze of the light diffusion layer 110 is preferably 60% or more, more preferably 70% or more, and particularly preferably 80% or more. By setting the haze of the light diffusion layer 110 to be equal to or higher than the lower limit value of the above range, the displayed image can be visually recognized in a wide angle range. The haze is preferably as high as described above, but is preferably 90% or less because it is easily available. The haze of the light diffusion layer 110 can be measured using a haze meter (“NDH-2000” manufactured by Nippon Denshoku Industries Co., Ltd.).

  The total light transmittance of the light diffusion layer 110 is preferably high. The specific range of the total light transmittance of the light diffusion layer 110 is preferably 80% or more, more preferably 85% or more, and particularly preferably 90% or more. By increasing the total light transmittance of the light diffusion layer 110 in this way, the brightness of the displayed image can be increased. The upper limit of the total light transmittance of the light diffusion layer 110 is ideally 100%, but is preferably 95% or less because it is easily available. The total light transmittance of the light diffusion layer 110 can be measured using a haze meter (“NDH-2000” manufactured by Nippon Denshoku Industries Co., Ltd.).

  The thickness of the light diffusion layer 110 is not particularly limited, and may be, for example, 30 μm to 200 μm.

Selective light reflecting layer 120 is a layer capable of selectively reflecting polarized light included in the projection light L _P. In the following description, polarized light that can be selectively reflected by the selective light reflective layer 120 may be referred to as “selective polarized light” as appropriate. An image projection system 10 according to this embodiment, the projection light L selective light reflecting layer 120 of the selective polarization contained in _P is selectively reflected, the selective reflection light reflected by the light reflecting layer 120 L _R As a result, an image is displayed. Here, “a layer that can selectively reflect selectively polarized light” means that when light enters the layer, it reflects the selectively polarized light in a specific wavelength band and transmits light other than the reflected selectively polarized light. It means the layer that can be. As such a selective light reflective layer 120, for example, a layer that reflects either circularly polarized light of left circularly polarized light or right circularly polarized light and transmits light other than the reflected circularly polarized light; and a certain direction And a layer that reflects linearly polarized light having a vibration direction and transmits light other than the reflected linearly polarized light. Here, the vibration direction of linearly polarized light means the vibration direction of the electric field of linearly polarized light. In the following description, the wavelength band in which the selective light reflective layer 120 can reflect selective polarized light may be referred to as “selective reflection band” as appropriate.

  From the viewpoint of displaying an image that can be viewed with the naked eye, the selective light reflective layer 120 preferably has a selective reflection band in the visible light region. Moreover, it is preferable that the wavelength width of the selective reflection band is wide from the viewpoint of widening the range of colors that can be used for image display. Specifically, the half width of the selective reflection band of the selective light reflective layer 120 is preferably 300 nm or more, more preferably 350 nm or more, and particularly preferably 400 nm or more. There is no particular limitation on the upper limit of the half-value width of the selective reflection band of the selective light reflective layer 120, but it can be 470 nm or less because it is easily available.

  The thickness of the selective light reflective layer 120 is not particularly limited, and may be 1 μm to 20 μm, for example.

  In this embodiment, right circularly polarized light is reflected as selective polarized light in the selective reflection band in the visible light region, and the reflected light other than right circularly polarized light (specifically, light having a wavelength outside the selective reflection band, and An example in which a layer capable of transmitting the selective reflection band (left circularly polarized light) is used as the selective light reflective layer 120 will be described.

The light absorption layer 130 is a layer that can absorb the illumination light L _L as the second light supplied from the illumination device 300. As the light absorption layer 130, a layer that can absorb a part of the illumination light L _L can be used, but a layer that can absorb all of the illumination light L _L is preferable. As the light absorbing layer 130, in addition to the illumination light L _L, it may be used a layer which can absorb the projection light L _P.

  As the light absorption layer 130, a layer having a low total light transmittance and a low total light reflectance can be used. The specific range of the total light transmittance of the light absorption layer 130 is preferably 1% or less, more preferably 0.1% or less, and particularly preferably 0.01% or less. The lower limit of the total light transmittance of the light absorbing layer 130 is ideally 0%. Further, the specific range of the total light reflectance of the light absorbing layer 130 is preferably 1% or less, more preferably 0.1% or less, and particularly preferably 0.01% or less. The lower limit of the total light reflectance of the light absorbing layer 130 is ideally 0%. As described above, the layer 130 having a low total light transmittance and a low total light reflectance can be substantially easily achieved by a general member such as black polyethylene terephthalate.

  The thickness of the light absorption layer 130 is not particularly limited, and may be, for example, 100 μm to 300 μm.

  In the present embodiment, an example in which an opaque black layer that can absorb all light in the visible light region is used as the light absorption layer 130 will be described.

Projection device 200 is a device capable of projecting a projection light L _P as a first light to the projection plane member 100 provided with a selective light reflecting layer 120. The projection apparatus 200, the reflected light L _R of the selected light reflecting layer 120 of the projection light L _P, are provided so as to be able to display an image. Therefore, the projection apparatus 200, used as it can project the projection light L _P including the selected polarization may be reflected by the selective light reflecting layer 120 provided on the projection surface member 100. Projection light L _P comprises may be a light containing only the selected polarization may be reflected by the selective light reflective layer 120, an optional polarization components in addition to the selected polarization may be reflected by the selective light reflecting layer 120 light It may be. Therefore, the projection light L _P may be non-polarized light may be polarized. In the present embodiment, it will be described an example of using a non-polarized light projection apparatus which can project the unpolarized light as the projection light L _P as a projection device 200.

The illumination device 300 is provided so that the environment in which the image projection system 10 is used can be brightened by illuminating the indoor space where the image projection system 10 is used with the illumination light L _L as the second light. Yes. Therefore, the projection surface member 100 can be illuminated by the illumination light L _L supplied by the illumination device 300. Image projection system 10 according to this embodiment, even in a bright environment where the projection plane member 100 with the illumination light L _L Thus a light other than the projection light L _P to be projected from the projection device 200 is illuminated, a high contrast It is provided so that an image can be displayed.

From the viewpoint of realizing a high contrast as described above, as illumination light L _L, is included in the projection light L _P using reverse polarization for the selected polarization may be reflected by the selective light reflecting layer 120. Here, the reverse polarization with respect to the selective polarization means a polarization in which one of the two components Ex and Ey of the electric field vector constituting the selective polarization has a phase shifted by π. For example, when the selectively polarized light is one of the left circularly polarized light and the right circularly polarized light, the inversely polarized light with respect to the selected polarized light represents the other of the left circularly polarized light and the right circularly polarized light. Further, for example, when the polarized light is linearly polarized light having a vibration direction in a certain direction, the inversely polarized light with respect to the selected polarized light represents linearly polarized light having a vibration direction perpendicular to the vibration direction of the selected polarized light. In the present embodiment, an example in which an illumination device that can supply left circularly polarized light as illumination light L _L is used as the illumination device 300 will be described.

As the illumination device 300 that can supply such polarized light as the illumination light L _L , a polarization source device that can emit polarized light may be used. Further, the illumination device 300 includes a non-polarization source device that can emit non-polarized light and a polarizing plate that can obtain polarized light from the non-polarized light, and supplies the polarized light that has passed through the polarizing plate as illumination light L _L. A composite light source device may be used. At this time, as the polarizing plate provided in the composite light source device for supplying linearly polarized light as the illumination light L _L , a linearly polarizing plate including a linear polarizer can be used. Moreover, as a polarizing plate provided in the composite light source device for supplying circularly polarized light as the illumination light L _L , a circularly polarizing plate provided with a combination of a linear polarizer and a quarter wavelength plate can be used. Here, the retardation Re of the quarter-wave plate is preferably 80 nm or more, more preferably 100 nm or more, particularly preferably 120 nm or more, preferably 180 nm or less, more preferably 160 nm or less, particularly preferably 150 nm or less. is there. As described above, various polarizing plates can be used, and among them, a polarizing plate provided with the same layer as the selective light reflective layer 120 of the projection surface member 100 is preferable as the polarizing plate provided in the lighting device 300. From a composite light source device including a polarizing plate including a layer similar to the selective light reflective layer 120 of the projection surface member 100, polarized light transmitted through the polarizing plate is supplied as illumination light L _L. Therefore, such a composite light source device can supply polarized light including only a light component that can be stably transmitted through the selective light reflective layer 120 of the projection surface member 100 as the illumination light L _L. In the present embodiment, a composite light source device that includes a polarizing plate that includes the same layer as the selective light reflective layer 120 and that can supply left circularly polarized light that can be transmitted through the selective light reflective layer 120 as illumination light L _L is used for illumination. An example in which the apparatus 300 is used will be described.

The image projection system 10 according to the first embodiment of the present invention has the structure described above. When using such an image projection system 10, in a bright environment lit illumination device 300, the projection apparatus 200 to the projection surface 100S of the projection surface member 100 projects the projection light L _P is a non-polarized light.

Projection light _{L P} passes through the light diffusion layer 110 of the projection surface member 100, enters the selective light reflecting layer 120. Of the projection light L _P having entered the selective light reflecting layer 120, right-circularly polarized light as a selected polarization is reflected as reflected light L _R by selective light reflecting layer 120, a projection plane member 100 through the light diffusion layer 110 Is sent outside the. Image is displayed by the reflected light L _R, the user can view the image by viewing the reflected light L _R. At this time, since the projection light L _P and the reflected light L _R is diffused by the light diffusion layer 110, the user can visually recognize the image in a wide range of angles, it can realize a wide viewing angle. On the other hand, among the projection light L _P having entered the selective light reflecting layer 120, the transmitted light L _T containing left-handed circularly polarized light not reflected by the selective light reflecting layer 120, enters the light absorbing layer 130, the light absorption Absorbed by layer 130.

Also, the illumination light L _L supplied from the illumination device 300 enters the selective light reflective layer 120 through the light diffusion layer 110 of the projection surface member 100. Since the illumination light L _L is not reflected by the selective light reflective layer 120, it enters the light absorption layer 130 through the selective light reflective layer 120 and is absorbed by the light absorption layer 130. For this reason, the illumination light L _L is difficult to see from the user, so that an increase in the luminance of the image due to the illumination light L _L is suppressed. Therefore, the contrast of the image displayed by the projection device 200 can be increased in a bright environment illuminated by the illumination light L _L supplied by the illumination device 300. In particular, in the present embodiment, since the composite light source device including the polarizing plate having the same layer as the selective light reflective layer 120 is used as the illumination device 300, the illumination light L _L stably uses the selective light reflective layer 120. It can be transmitted. For this reason, it is possible to effectively suppress a part of the illumination light L _{L from} being unintentionally reflected by the selective light reflective layer 120, so that the contrast can be particularly increased.

The image projection system 10 according to the first embodiment of the present invention has been described in detail above, but the image projection system may be further modified and implemented.
For example, in the above-described embodiment, the example in which the selective polarization is the right circular polarization and the illumination light L _L is the left circular polarization, but the combination of the selection polarization and the illumination light L _L is not limited thereto. For example, the selective polarization may be left circular polarization and the illumination light L _L may be right circular polarization. Alternatively, the polarized light may be linearly polarized light having a vibration direction in a certain direction and the illumination light L _L may be linearly polarized light having a vibration direction perpendicular to the vibration direction of the selected polarization. When using linearly polarized light as a selected polarization and illumination light L _L, in order to enhance the visibility due to a general polarized sunglass, preferably having a vibration direction in the vertical direction linear polarization of the selected polarization, as the illuminating light L _L The linearly polarized light preferably has a vibration direction in the horizontal direction.

  In the above-described embodiment, an example in which a screen is used as the projection surface member 100 has been described. However, a member other than the screen may be used as the projection surface member 100. For example, a wall material and window material of a house, a wall material and window material of a vehicle may be used as the projection surface member 100. Especially, it is preferable that the projection surface member 100 is a screen or a wall material.

  Further, for example, the projection surface member 100 may further include an arbitrary layer in combination with the light diffusion layer 110, the selective light reflective layer 120, and the light absorption layer 130. Examples of the optional layer include an adhesive layer for bonding the light diffusion layer 110, the selective light reflection layer 120, and the light absorption layer 130; a support layer for increasing the mechanical strength of the projection surface member 100; 110, a protective layer for protecting the selective light reflective layer 120 and the light absorption layer 130; and the like.

Moreover, although the example which used the non-polarization projection apparatus which can project a non-polarization as the projection apparatus 200 was shown in embodiment mentioned above, the polarization projection apparatus which can project a polarization may be used as the projection apparatus 200. As such a polarization projection apparatus, for example, a polarization source apparatus that can emit polarized light, and an apparatus that can project the polarization emitted by the polarization source apparatus may be used. In addition, as the polarization projection device, for example, a non-polarization source device that can emit non-polarized light and a polarizing plate that can obtain polarized light from the non-polarized light, and a composite projection device that can project polarized light transmitted through the polarizing plate It may be used. In this case, as the polarizing plate, the linearly polarizing plate comprising a linear polarizer, such as a circularly polarizing plate including a combination of a linear polarizer and a quarter-wave plate, depending on the type of polarization to be projected as a projection light L _P Any polarizing plate can be used. Furthermore, as a polarizing plate, you may use the polarizing plate provided with a cholesteric resin layer.

[2. Second embodiment]
In the first embodiment described above, although the image projection system 10 using the illumination device 300 which generates illumination light L _L as its own second light as the second light source, the second light source, the The second light supply source itself may not generate the illumination light L _L. For example, a member that can obtain illumination light L _L as polarized light from natural light may be used as the second light supply source. Hereinafter, an example of such an image projection system will be described as a second embodiment.

  FIG. 3 is a schematic diagram schematically showing the image projection system 20 according to the second embodiment of the present invention. As shown in FIG. 3, the image projection system 20 according to the second embodiment of the present invention is the same as the image projection system 10 according to the first embodiment except that a polarization transmission filter 400 is provided instead of the illumination device 300. A projection surface member 100, a projection device 200, and a polarization transmission filter 400 as a second light supply source are provided.

The polarization transmission filter 400 is a filter that can transmit polarized light for use as illumination light L _L in natural light and block light other than the polarized light to be transmitted. The polarization transmission filter 400 is usually provided in a window of a room where the image projection system 20 is installed. In this case, among the natural light entering the room through the window, the illumination light L _L as polarized light passes through the polarization transmission filter 400, but other light is blocked by the polarization transmission filter 400. Thus, the polarization transmission filter 400 is used by the image projection system 20 by illuminating the space in which the image projection system 20 is used with the illumination light L _L as the second light supplied by the polarization transmission filter 400. It is provided to brighten the environment.

In the present embodiment, the illumination light L _L, using reverse polarization for the selected polarization may be reflected by the selective light reflecting layer 120 included in the projection light L _P. In order to enable supply of such illumination light L _L, a filter including a polarizing plate can be used as the polarization transmission filter 400. At this time, as the polarizing plate, depending on the type of polarized light to be supplied as the illumination light L _L , such as a linear polarizing plate provided with a linear polarizer, a circular polarizing plate provided with a combination of a linear polarizer and a quarter wave plate, etc. Any polarizing plate can be used. Among these, as the polarization transmission filter 400, a composite light source device including a polarizing plate including a layer similar to the selective light reflective layer 120 of the projection surface member 100 is preferable. In the present embodiment, the polarizing plate includes a polarizing plate that includes the same layer as the selective light reflective layer 120 and can supply left circularly polarized light that can be transmitted through the selective light reflective layer 120 as illumination light L _L. An example used as 400 will be described.

The image projection system 20 according to the second embodiment of the present invention has the structure described above. When such an image projection system 20 is used, in a bright environment illuminated by the illumination light L _L captured through the polarization transmission filter 400, the projection apparatus 200 is unpolarized to the projection plane 100S of the projection plane member 100. projecting the projection light _{L P.}

FIG. 4 is a schematic view schematically showing the image projection system 20 according to the second embodiment of the present invention. In FIG. 4, the projection plane member 100 is shown cut along a plane perpendicular to the projection plane 100 </ b> S of the projection plane member 100. In addition, the reflection of light by the selective light reflective layer 120 may occur not only on the surface of the selective light reflective layer 120 but also inside, but as a schematic representation, in FIG. The reflection of light is illustrated as occurring on the surface of the selective light reflective layer 120.
As shown in FIG. 4, of the projection light L _P, the right circularly polarized light as a selected polarization is reflected as reflected light L _R by selective light reflecting layer 120, an image is displayed by the reflected light L _R. On the other hand, among the projection light L _P having entered the selective light reflecting layer 120, the transmitted light L _T containing left-handed circularly polarized light not reflected by the selective light reflecting layer 120, it is absorbed by the light absorbing layer 130.

Also, the illumination light L _L supplied by the polarization transmission filter 400 enters the light absorption layer 130 through the light diffusion layer 110 and the selective light reflective layer 120 of the projection surface member 100 and is absorbed by the light absorption layer 130. The For this reason, the illumination light L _L is difficult to see from the user, and thus an increase in the luminance of the image due to the illumination light L _L can be suppressed. Therefore, the contrast of the image displayed by the projection device 200 can be increased in a bright environment illuminated by the illumination light L _L supplied by the polarization transmission filter 400. Furthermore, in this embodiment, the same advantages as the first embodiment can be obtained.

The image projection system 20 according to the second embodiment of the present invention has been described in detail above, but the image projection system may be further modified and implemented.
For example, the image projection system 20 according to the present embodiment may be modified and implemented in the same manner as described in the first embodiment of the present invention.

[3. Selective light reflective layer]
Hereinafter, the selective light reflective layer included in the projection surface member will be described. As the selective light reflective layer, an appropriate layer can be arbitrarily used depending on the selective polarization to be selectively reflected.

  For example, a layer including a cholesteric resin layer can be used as the selective light reflective layer that can selectively reflect one of left circularly polarized light and right circularly polarized light. The cholesteric resin layer is a resin layer containing molecules having cholesteric regularity. Usually, in the cholesteric resin layer, the polymer molecules contained in the cholesteric resin layer have cholesteric regularity. Here, “cholesteric regularity” means that the molecular axes are aligned in a certain direction on one plane, but the direction of the molecular axis is shifted by an angle in the next plane that overlaps it, and in the next plane, As the angle further shifts, the structure is such that the angle of the molecular axis in the plane is shifted (twisted) as it sequentially passes through the overlapping planes. Thus, the structure in which the direction of the molecular axis is continuously twisted is usually a spiral structure and an optically chiral structure. The normal line (helical axis) of the plane is preferably substantially parallel to the thickness direction of the cholesteric resin layer.

  Such a cholesteric resin layer can selectively reflect circularly polarized light. Therefore, when light is incident on the cholesteric resin layer, only the left circularly polarized light or the right circularly polarized light in the selective reflection band light is reflected, and the light other than the reflected circularly polarized light is transmitted. Therefore, a selective light reflective layer can be obtained by using this cholesteric resin layer. Usually, the reflection in the cholesteric resin layer reflects circularly polarized light while maintaining its chirality.

  The wavelength at which the cholesteric resin layer can selectively reflect circularly polarized light depends on the pitch of the helical structure in the cholesteric resin layer. Here, the pitch of the helical structure is the distance in the plane normal direction until the angle of the molecular axis in the helical structure gradually shifts as it advances along the plane and then returns to the original molecular axis direction again. . Therefore, the wavelength at which circularly polarized light can be selectively reflected can be controlled by adjusting the pitch of the spiral structure. Examples of the cholesteric resin layer that can selectively reflect circularly polarized light in a wide selective reflection band include (i) a cholesteric resin layer in which the pitch of the spiral structure is changed stepwise, and (ii) a spiral structure Examples thereof include a cholesteric resin layer in which the pitch is continuously changed.

  The cholesteric resin layer is produced, for example, by a production method including a step of providing a cholesteric liquid crystal composition layer on an appropriate substrate and a step of curing the cholesteric liquid crystal composition layer to obtain a cholesteric resin layer. sell.

  As the cholesteric liquid crystal composition for forming the cholesteric resin layer, a composition containing a liquid crystal compound and capable of exhibiting a cholesteric liquid crystal phase when formed into a layer can be used. Here, as the liquid crystal compound, a liquid crystal compound which is a polymer compound and a polymerizable liquid crystal compound can be used. In order to obtain high thermal stability, it is preferable to use a polymerizable liquid crystal compound. By polymerizing such a polymerizable liquid crystalline compound in a state exhibiting cholesteric regularity, the layer of the cholesteric liquid crystal composition is cured to obtain a non-liquid crystalline cholesteric resin layer cured while exhibiting cholesteric regularity. Can do. Note that the material referred to as a liquid crystal composition here for convenience includes not only a mixture of two or more substances but also a material made of a single substance.

  (I) A cholesteric resin layer in which the pitch of the spiral structure is changed stepwise manufactures a plurality of cholesteric resin layers having different helical structure pitches, and these cholesteric resin layers are bonded together via an adhesive or an adhesive. It can be manufactured by a method. Alternatively, (i) a cholesteric resin layer in which the pitch of the helical structure is changed stepwise can be manufactured by a method in which another cholesteric resin layer is sequentially formed after a certain cholesteric resin layer is formed.

  Further, (ii) the cholesteric resin layer in which the pitch of the spiral structure is continuously changed is a layer of the cholesteric liquid crystal composition obtained by coating a cholesteric liquid crystal composition containing a polymerizable liquid crystal compound on a substrate. A step of continuously changing the pitch of the spiral structure by one or more times of light irradiation and / or heating treatment, and a state in which the pitch of the spiral structure is continuously changed in this way, And a step of curing the layer of the cholesteric liquid crystal composition. Since the operation of continuously changing the pitch of the spiral structure is an operation of extending the selective reflection band of the cholesteric resin layer, it is called “broadband processing”.

As the cholesteric liquid crystal composition used for such a broadening treatment, a liquid crystal composition containing a compound represented by the following formula (1) and a specific rod-like liquid crystalline compound is preferable.
R ¹ -A ¹ -BA ² -R ² (1)

In the formula (1), R ¹ and R ² are each independently a linear or branched alkyl group having 1 to 20 carbon atoms, or a straight chain having 1 to 20 carbon atoms. Or a branched alkylene oxide group, a hydrogen atom, a halogen atom, a hydroxyl group, a carboxyl group, a (meth) acryl group, an epoxy group, a mercapto group, an isocyanate group, an amino group, which may have an arbitrary linking group interposed, And a group selected from the group consisting of a cyano group.

  The alkyl group and alkylene oxide group may be unsubstituted or substituted with one or more halogen atoms. The halogen atom, hydroxyl group, carboxyl group, (meth) acryl group, epoxy group, mercapto group, isocyanate group, amino group, and cyano group are bonded to an alkyl group having 1 to 2 carbon atoms and an alkylene oxide group. You may do it.

Preferred examples of R ¹ and R ² include a halogen atom, a hydroxyl group, a carboxyl group, a (meth) acryl group, an epoxy group, a mercapto group, an isocyanate group, an amino group, and a cyano group.

In addition, at least one of R ¹ and R ² is preferably a reactive group. By having a reactive group as at least one of R ¹ and R ^2, the compound represented by the formula (1) is fixed in the cholesteric resin layer at the time of curing, and a stronger layer can be formed. Here, examples of the reactive group include a carboxyl group, a (meth) acryl group, an epoxy group, a mercapto group, an isocyanate group, and an amino group in which an arbitrary linking group may be interposed.

In Formula (1), A ¹ and A ² are each independently 1,4-phenylene group, 1,4-cyclohexylene group, 1,4-cyclohexenyl group, 4,4′-biphenylene group, 4 , 4′-bicyclohexylene group and a group selected from the group consisting of 2,6-naphthylene group. The 1,4-phenylene group, 1,4-cyclohexylene group, 1,4-cyclohexenyl group, 4,4′-biphenylene group, 4,4′-bicyclohexylene group, and 2,6-naphthylene group are Are not substituted, or are substituted by one or more substituents such as a halogen atom, a hydroxyl group, a carboxyl group, a cyano group, an amino group, an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group, etc. It may be. In each of A ¹ and A ² , when two or more substituents are present, they may be the same or different.

Particularly preferred as A ¹ and A ² are groups selected from the group consisting of 1,4-phenylene group, 4,4′-biphenylene group, and 2,6-naphthylene group. These aromatic ring skeletons are relatively rigid as compared with the alicyclic skeleton, have a high affinity with the mesogen of the rod-like liquid crystalline compound, and have higher alignment uniformity ability.

In the formula (1), B represents a single bond, —O—, —S—, —S—S—, —CO—, —CS—, —OCO—, —CH ₂ —, —OCH ₂ —, —CH. = N-N = CH -, - NHCO -, - OCOO -, - CH 2 COO-, and is selected from the group consisting of _-CH 2 OCO-.

  Particularly preferable examples of B include a single bond, —OCO—, and —CH═N—N═CH—.

  At least one of the compounds represented by the formula (1) preferably has liquid crystallinity, and preferably has chirality. In addition, the compound represented by the formula (1) is preferably used in combination of a plurality of optical isomers. For example, a mixture of a plurality of types of enantiomers, a mixture of a plurality of types of diastereomers, or a mixture of enantiomers and diastereomers may be used. At least one of the compounds represented by formula (1) preferably has a melting point in the range of 50 ° C to 150 ° C.

  When the compound represented by Formula (1) has liquid crystallinity, the compound represented by Formula (1) preferably has a high refractive index anisotropy Δn. By including a liquid crystalline compound having a high refractive index anisotropy Δn, the refractive index anisotropy Δn of the cholesteric liquid crystal composition can be improved, and a cholesteric resin layer having a wide selective reflection band can be produced. At least one refractive index anisotropy Δn of the compound represented by the formula (1) is preferably 0.18 or more, more preferably 0.22 or more.

  Specific examples of particularly preferred compounds represented by the formula (1) include the following compounds (A1) to (A9). Moreover, the compound represented by Formula (1) may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

  In the compound (A3), “*” represents a chiral center.

The cholesteric liquid crystal composition preferably contains a rod-like liquid crystal compound having at least two reactive groups in one molecule. Preferable examples of the rod-like liquid crystalline compound include a compound represented by the formula (2).
R ³ -C ³ -D ³ -C ⁵ -M C ⁶ -D ⁴ -C ⁴ -R ⁴ Formula (2)

In the formula (2), R ³ and R ⁴ are reactive groups, each independently (meth) acryl group, (thio) epoxy group, oxetane group, thietanyl group, aziridinyl group, pyrrole group, vinyl group. , An allyl group, a fumarate group, a cinnamoyl group, an oxazoline group, a mercapto group, an iso (thio) cyanate group, an amino group, a hydroxyl group, a carboxyl group, and an alkoxysilyl group. D ³ and D ⁴ are each a single bond, a linear or branched alkyl group having 1 to 20 carbon atoms, and a linear or branched alkylene oxide group having 1 to 20 carbon atoms. Represents a group selected from the group consisting of C ^{3 to} C ⁶ are each independently a single bond, —O—, —S—, —S—S—, —CO—, —CS—, —OCO—, —CH ₂ —, —OCH ₂ —. , -CH = N-N = CH -, - NHCO -, - OCOO -, - CH 2 COO-, and represents a group selected from the group consisting of _-CH 2 OCO-. M represents a mesogenic group, and specifically, azomethines, azoxys, phenyls, biphenyls, terphenyls, naphthalenes, anthracenes, benzoic acid, which may be unsubstituted or substituted. 2-4 selected from the group of esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, alkoxy-substituted phenylpyrimidines, phenyldioxanes, tolanes, alkenylcyclohexylbenzonitriles The skeleton is represented by —O—, —S—, —S—S—, —CO—, —CS—, —OCO—, —CH ₂ —, —OCH ₂ —, —CH═N—N═CH—, — _{NHCO -, - OCOO -, -} CH 2 COO-, and is formed are joined by a linking group of _-CH 2 OCO- or the like.

Examples of the substituent that the mesogenic group M may have include, for example, a halogen atom, an optionally substituted alkyl group having 1 to 10 carbon atoms, a cyano group, a nitro group, —O—R ⁵ , —O—C. (═O) —R ⁵ , —C (═O) —O—R ⁵ , —O—C (═O) —O—R ⁵ , —NR ⁵ —C (═O) —R ⁵ , —C ( ═O) —NR ⁵ R ⁷ , or —O—C (═O) —NR ⁵ R ⁷ . Wherein, ^{R 5} and ^{R 7} represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, when it is alkyl group, and the alkyl group, -O -, - S -, - O-C (= O) —, —C (═O) —O—, —O—C (═O) —O—, —NR ⁶ —C (═O) —, —C (═O) —NR ⁶ —, —NR ^6- or -C (= O)-may be present (except when two or more of -O- and -S- are present adjacent to each other). Here, R ⁶ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
Examples of the substituent in the “optionally substituted alkyl group having 1 to 10 carbon atoms” include, for example, a halogen atom, a hydroxyl group, a carboxyl group, a cyano group, an amino group, and 1 to 6 carbon atoms. An alkoxy group having 2 to 8 carbon atoms, an alkoxyalkoxyalkoxy group having 3 to 15 carbon atoms, an alkoxycarbonyl group having 2 to 7 carbon atoms, and an alkyl having 2 to 7 carbon atoms Examples thereof include a carbonyloxy group and an alkoxycarbonyloxy group having 2 to 7 carbon atoms.

The rod-like liquid crystalline compound preferably has an asymmetric structure. Here, the asymmetric structure is a structure in which R ³ -C ³ -D ³ -C ⁵ -and -C ⁶ -D ⁴ -C ⁴ -R ⁴ are different from each other in the formula (2) with the mesogenic group M as the center. Say. By using a rod-shaped liquid crystalline compound having an asymmetric structure, alignment uniformity can be further improved.

  The refractive index anisotropy Δn of the rod-like liquid crystal compound is preferably 0.18 or more, more preferably 0.22 or more. When a compound having a refractive index anisotropy Δn of 0.30 or more is used, the absorption edge on the long wavelength side of the ultraviolet absorption spectrum may extend to the visible range, but it is desirable even if the absorption edge of the spectrum extends to the visible range. As long as the optical performance is not adversely affected, it can be used. By having such a high refractive index anisotropy Δn, a cholesteric resin layer having high optical performance (for example, selective reflection performance of circularly polarized light) can be obtained.

  The rod-like liquid crystalline compound may have two or more reactive groups in one molecule. Examples of reactive groups include epoxy groups, thioepoxy groups, oxetane groups, thietanyl groups, aziridinyl groups, pyrrole groups, fumarate groups, cinnamoyl groups, isocyanate groups, isothiocyanate groups, amino groups, hydroxyl groups, carboxyl groups, alkoxysilyls. Groups, oxazoline groups, mercapto groups, vinyl groups, allyl groups, methacryl groups, and acrylic groups. By having these reactive groups, when the cholesteric liquid crystal composition is cured, a stable cured product having a film strength that can withstand practical use can be obtained. The film strength that can withstand practical use is pencil hardness (JIS K5400), preferably HB or more, more preferably H or more. Since the film strength is high as described above, the film is hardly scratched and has excellent handling properties. The upper limit of the preferred pencil hardness is not particularly limited as long as it does not adversely affect the optical performance and durability test.

  Preferable specific examples of the rod-like liquid crystalline compound include the following compounds (B1) to (B9), but the rod-like liquid crystalline compound is not limited to the following compounds. Moreover, a rod-shaped liquid crystalline compound may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

  The weight ratio represented by “(total weight of compounds represented by formula (1)) / (total weight of rod-like liquid crystalline compound)” is preferably 0.05 or more, more preferably 0.1 or more, particularly preferably. Is 0.15 or more, preferably 1 or less, more preferably 0.65 or less, and particularly preferably 0.45 or less. By setting the weight ratio to be equal to or higher than the lower limit of the above range, alignment uniformity can be enhanced in the layer of the cholesteric liquid crystal composition. Further, by setting the upper limit value or less, the alignment uniformity can be increased. In addition, the stability of the liquid crystal phase of the cholesteric liquid crystal composition can be increased. Furthermore, since the refractive index anisotropy Δn of the cholesteric liquid crystal composition can be increased, a cholesteric resin layer having desired optical performance (for example, selective reflection performance of circularly polarized light) can be stably obtained. Here, the total weight indicates the weight when one type is used, and indicates the total weight when two or more types are used.

  In the cholesteric liquid crystal composition, the molecular weight of the compound represented by the formula (1) is preferably less than 600, and the molecular weight of the rod-like liquid crystal compound is preferably 600 or more. Thereby, the fluidity of the cholesteric liquid crystal composition is increased, and the uniformity of the liquid crystal alignment can be improved.

  The cholesteric liquid crystal composition can optionally contain a crosslinking agent in order to improve the film strength and durability after curing. The cross-linking agent increases the cross-linking density of the cholesteric resin layer by, for example, reacting when the layer of the cholesteric liquid crystal composition is cured, promoting the reaction by heat treatment after curing, or allowing the reaction to proceed spontaneously due to moisture. be able to. As a crosslinking agent, what can react with an ultraviolet-ray, a heat | fever, humidity, etc. can be used, for example. Among these, as the crosslinking agent, those that do not deteriorate the alignment uniformity are preferable.

  Specific examples of the crosslinking agent include trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and 2- (2-vinyloxyethoxy). ) Polyfunctional acrylate compounds such as ethyl acrylate; Epoxy compounds such as glycidyl (meth) acrylate, ethylene glycol diglycidyl ether, glycerin triglycidyl ether, pentaerythritol tetraglycidyl ether; 2,2-bishydroxymethylbutanol-tris [3- (1-aziridinyl) propionate], 4,4-bis (ethyleneiminocarbonylamino) diphenylmethane, trimethylolpropane-tri-β-aziridinyl Aziridine compounds such as pionate; isocyanate compounds such as isocyanurate type isocyanate, biuret type isocyanate and adduct type isocyanate derived from hexamethylene diisocyanate, hexamethylene diisocyanate; polyoxazoline compound having an oxazoline group in the side chain; vinyltrimethoxysilane; N- (2-aminoethyl) 3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3- (meth) acryloxypropyltrimethoxysilane, N- (1 , 3-dimethylbutylidene) -3- (triethoxysilyl) -1-propanamine and the like alkoxysilane compounds. Moreover, a crosslinking agent may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios. Furthermore, a catalyst may be used according to the reactivity of the crosslinking agent. By using a catalyst, productivity can be improved in addition to improvement in film strength and durability.

  The amount of the crosslinking agent is preferably such that the amount of the crosslinking agent in the cholesteric resin layer obtained by curing the cholesteric liquid crystal composition is 0.1% by weight to 15% by weight. By setting the amount of the crosslinking agent to be not less than the lower limit of the above range, the crosslinking density can be effectively increased. Moreover, the uniformity of the liquid crystal orientation of a cholesteric liquid crystal composition can be hold | maintained by setting it as an upper limit or less.

  The cholesteric liquid crystal composition can optionally contain a photopolymerization initiator. As a photoinitiator, the compound which generate | occur | produces a radical or an acid with an ultraviolet-ray or visible light can be used, for example. Specific examples of the photopolymerization initiator include benzoin, benzylmethyl ketal, benzophenone, biacetyl, acetophenone, Michler's ketone, benzyl, benzylisobutyl ether, tetramethylthiuram mono (di) sulfide, 2,2-azobisisobutyronitrile, 2,2-azobis-2,4-dimethylvaleronitrile, benzoyl peroxide, di-tert-butyl peroxide, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-diethylthioxanthone, methylbenzoylforme 2,2-diethoxyacetophenone, β-ionone, β-bromostyrene, diazoaminobenzene, α-amylcinnamic aldehyde, p-dimethylaminoacetophenone, p-dimethylaminopropiophenone, 2-chlorobenzophenone, pp ′ -Dichlorobenzophenone, pp'-bisdiethylaminobenzophenone, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-propyl ether, benzoin n-butyl ether, diphenyl sulfide, bis (2,6-methoxybenzoyl) -2,4,4-trimethyl -Pentylphosphine oxide, 2,4,6-trimethylbenzoyldiphenyl-phosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxine Id, 2-methyl-1 [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one , Anthracene benzophenone, α-chloroanthraquinone, diphenyl disulfide, hexachlorobutadiene, pentachlorobutadiene, octachlorobutene, 1-chloromethylnaphthalene, 1,2-octanedione, 1- [4- (phenylthio) -2- (o -Benzoyloxime)] and 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl] ethanone 1- (o-acetyloxime), (4-methylphenyl) ) [4- (2-Methylpropyl) phenyl] iodonium hexafluo Phosphate, 3-methyl-2-butynyl tetramethyl hexafluoroantimonate, diphenyl - (p-phenylthiophenyl) sulfonium hexafluoroantimonate, and the like. Moreover, these may be used individually by 1 type and may be used combining two or more types by arbitrary ratios. Furthermore, you may control sclerosis | hardenability using the tertiary amine compound as a photosensitizer or a polymerization accelerator as needed.

  The amount of the photopolymerization initiator is preferably 0.03% by weight to 7% by weight in the cholesteric liquid crystal composition. Since the polymerization degree can be increased by setting the amount of the photopolymerization initiator to be equal to or higher than the lower limit of the above range, the film strength of the cholesteric resin layer can be increased. Moreover, since the orientation of a liquid crystalline compound can be made favorable by setting it to the upper limit value or less, the liquid crystal phase of the cholesteric liquid crystal composition can be stabilized.

  The cholesteric liquid crystal composition can optionally contain a surfactant. As the surfactant, for example, one that does not inhibit the orientation can be appropriately selected and used. As such a surfactant, for example, a nonionic surfactant containing a siloxane or a fluorinated alkyl group in the hydrophobic group portion is preferably exemplified. Of these, oligomers having two or more hydrophobic group moieties in one molecule are particularly suitable. Specific examples of these surfactants include “PF-151N”, “PF-636”, “PF-6320”, “PF-656”, “PF-6520”, “PF-3320” of PolyFox, OMNOVA. , “PF-651”, “PF-652”; “FTX-209F”, “FTX-208G”, “FTX-204D” from Neos's footagent; “KH-40” from Seimi Chemical Co., Ltd. Can do. Moreover, surfactant may be used individually by 1 type and may be used combining two or more types by arbitrary ratios.

  The amount of the surfactant is preferably such that the amount of the surfactant in the cholesteric resin layer obtained by curing the cholesteric liquid crystal composition is 0.05% by weight to 3% by weight. By setting the amount of the surfactant to be equal to or higher than the lower limit of the above range, the alignment regulating force at the air interface can be increased, so that alignment defects can be prevented. Moreover, by making it into the upper limit value or less, it is possible to prevent a decrease in alignment uniformity due to excessive surfactant entering between liquid crystal molecules.

  The cholesteric liquid crystal composition can optionally contain a chiral agent. Specific examples of the chiral agent include JP-A-2005-289881, JP-A-2004-115414, JP-A-2003-66214, JP-A-2003-313187, JP-A-2003-342219, JP-A-2003-342219. 2000-290315, JP-A-6-072962, U.S. Pat. No. 6,468,444, WO 98/00428, JP-A 2007-176870, etc. can be used as appropriate. For example, it is available as LC756 of BASF Corporation Paliocolor. Moreover, a chiral agent may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

  The amount of the chiral agent can be arbitrarily set within a range not deteriorating the desired optical performance. The specific amount of the chiral agent is preferably 1% by weight to 60% by weight in the cholesteric liquid crystal composition.

  The cholesteric liquid crystal composition may further contain an optional component as necessary. Examples of the optional component include a solvent, a polymerization inhibitor for improving pot life, an antioxidant for improving durability, an ultraviolet absorber, and a light stabilizer. As the optional component, one type may be used alone, or two or more types may be used in combination at any ratio. The amount of these optional components can be set within a range that does not deteriorate the desired optical performance.

  After preparing a cholesteric liquid crystal composition, a cholesteric resin layer can be obtained by providing a layer of the cholesteric liquid crystal composition on a substrate, performing an alignment treatment as necessary, and then performing a curing treatment.

  As the substrate, a resin film having a total light transmittance of 80% or more at a thickness of 1 mm is usually used. Specific examples of the substrate include alicyclic olefin resin, chain olefin resin such as polyethylene resin and polypropylene resin, triacetyl cellulose resin, polyvinyl alcohol resin, polyimide resin, polyarylate resin, polyester resin, polycarbonate resin, polysulfone resin. And a monolayer or laminated film made of a synthetic resin such as a polyethersulfone resin, a modified acrylic resin, an epoxy resin, a polystyrene resin, or an acrylic resin. Among these, an alicyclic olefin resin or a chain olefin resin film is preferable, and an alicyclic olefin resin film is particularly preferable from the viewpoints of transparency, low moisture absorption, dimensional stability, and lightness. Further, the resin film as the substrate may be a stretched film that has been subjected to a stretching treatment.

  The substrate may be provided with an alignment film before the layer of the cholesteric liquid crystal composition is provided. The alignment film can be formed of, for example, cellulose, silane coupling agent, polyimide, polyamide, polyvinyl alcohol, epoxy acrylate, silanol oligomer, polyacrylonitrile, phenol resin, polyoxazole, cyclized polyisoprene, etc. preferable. As the modified polyamide, for example, an aromatic polyamide or an aliphatic polyamide that has been modified can be used. Of these, a modified aliphatic polyamide is particularly preferred. Preferable examples include nylon-6, nylon-66, nylon-12, ternary to quaternary copolymer nylon, fatty acid polyamide, or fatty acid block copolymer (eg, polyether ester amide, polyester amide). The thing which modified | denatured can be mentioned. Examples of the modification include terminal amino modification, carboxyl modification, hydroxyl modification, and the like, and modification in which a part of the amide group is alkylaminated or N-alkoxyalkylated. Examples of the N-alkoxyalkylated modified polyamide include N-methoxymethylated part of the amide group of copolymer nylon such as nylon-6, nylon-66, or nylon-12. The weight average molecular weight of the modified polyamide is preferably 5,000 to 500,000, more preferably 10,000 to 200,000.

The alignment film can be produced, for example, by applying a solution containing the above-described material onto a substrate, drying, and performing a rubbing treatment. Examples of the coating method at this time include a reverse gravure coating method, a direct gravure coating method, a die coating method, and a bar coating method.
The thickness of the alignment film is preferably 0.001 μm to 5 μm, and more preferably 0.01 μm to 2 μm. When the substrate includes an alignment film, a layer of a cholesteric liquid crystal composition is usually provided on the alignment film.

  Furthermore, before providing the layer of the cholesteric liquid crystal composition or before providing the alignment film, the surface of the substrate may be subjected to a surface treatment such as a corona discharge treatment or a rubbing treatment, if necessary.

  The formation of the cholesteric liquid crystal composition layer is usually carried out by a coating method. Examples of the coating method include an extrusion coating method, a direct gravure coating method, a reverse gravure coating method, a die coating method, and a bar coating method.

  After providing a layer of the cholesteric liquid crystal composition on the substrate, an alignment treatment may be performed as necessary. The alignment treatment can be performed, for example, by heating the cholesteric liquid crystal composition layer at 50 to 150 ° C. for 0.5 to 10 minutes. By performing the alignment treatment, the cholesteric liquid crystal composition in the layer of the cholesteric liquid crystal composition is well aligned, and the molecules of the liquid crystalline compound are in a state exhibiting cholesteric regularity.

Thereafter, a curing process is performed to cure the layer of the cholesteric liquid crystal composition. The curing process can be performed, for example, by a combination of one or more light irradiations and a heating process.
In the heating condition, the heating temperature is preferably 40 ° C. or higher, more preferably 50 ° C. or higher, and preferably 200 ° C. or lower, more preferably 140 ° C. or lower. The heating time is preferably 1 second or longer, more preferably 5 seconds or longer, and preferably 3 minutes or shorter, more preferably 120 seconds or shorter.
Moreover, the light used for light irradiation includes not only visible light but also ultraviolet rays and other electromagnetic waves. The light irradiation can be performed, for example, by irradiating light having a wavelength of 200 nm to 500 nm for 0.01 second to 3 minutes. At this time, the energy of light irradiated, for ^example, may be a ^{0.01mJ / cm 2 ~50mJ / cm 2} .

By repeating 0.01mJ ^/ cm ² ~50mJ / cm 2 of weak ultraviolet irradiation and heating Metropolitan several times alternately, the size of the pitch of the helical structure continuously greatly change, wide selective reflection band A cholesteric resin layer can be obtained. Further, after the extension of the selective reflection band due to weak UV irradiation, or the like described above, for example relatively strong ultraviolet radiation such ^{50mJ / cm 2 ~10,000mJ / cm 2} , to completely polymerize the liquid crystal compound Thus, a cholesteric resin layer having high mechanical strength can be obtained. The expansion of the selective reflection band and the irradiation with strong ultraviolet rays may be performed in the air, or part or all of the process may be performed in an atmosphere in which the oxygen concentration is controlled (for example, in a nitrogen atmosphere).

  The steps of applying and curing the cholesteric liquid crystal composition as described above are not limited to once, and the application and curing may be repeated a plurality of times. Thereby, the cholesteric resin layer containing two or more layers can be formed. However, by using the cholesteric liquid crystal composition containing the compound represented by the formula (1) and the specific rod-like liquid crystalline compound described in the above example, the coating and curing of the cholesteric liquid crystal composition can be performed only once. A cholesteric resin layer containing a well-oriented rod-like liquid crystalline compound and having a thickness of 5 μm or more can be easily formed.

  When manufacturing a cholesteric resin layer by such a manufacturing method, the twist direction of a cholesteric resin layer can be selected with the kind (structure) of the chiral agent to be used. Specifically, when the torsion direction is the right direction, a chiral agent that imparts dextrorotation is used, and when the torsion direction is the left direction, it is realized by using a chiral agent that imparts levorotation. it can.

  The thickness of the cholesteric resin layer is preferably 0.1 μm or more and more preferably 1 μm or more in order to obtain sufficient reflectance. Moreover, when obtaining the transparency of a cholesteric resin layer, it is preferable that it is 20 micrometers or less, and it is more preferable that it is 10 micrometers or less. Here, the thickness of the cholesteric resin layer refers to the total thickness of each layer when the selective light reflective layer has two or more layers, and when the cholesteric resin layer is one layer, Refers to its thickness.

  The cholesteric resin layer obtained by the production method described above may be peeled off from the substrate and used alone as the selective light reflective layer by the cholesteric resin layer alone. In addition, when the base material does not interfere with the display of the image, a member having a multilayer structure including the base material and the cholesteric resin layer may be used as the selective light reflective layer without peeling off the cholesteric resin layer from the base material. Good.

  For example, as the selective light reflective layer capable of selectively reflecting linearly polarized light, for example, a linearly polarized light reflecting element layer using birefringence as described in Japanese Patent No. 3448626 can be used. Furthermore, as the selective light reflective layer capable of selectively reflecting linearly polarized light, for example, a reflective polarizer layer in which the above-described cholesteric resin layer and a quarter wavelength plate are combined may be used.

[4. Application]
The above-described image projection system can be used in a building, for example. Moreover, the image projection system mentioned above can be used in a vehicle, for example. When used in a vehicle, the projection surface member may be provided as a screen in the vehicle, or may be provided in a vehicle portion such as a wall portion and a ceiling portion, or in a window portion such as a side glass and a rear glass. In particular, when a selective light reflective layer including a cholesteric resin layer is used, the cholesteric resin layer is usually a translucent layer having a half mirror function, so that even if the cholesteric resin layer is provided on the window, the field of view of the window is greatly hindered. Since there is no, it is preferable.

Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to the following examples, and can be implemented with any modifications without departing from the scope of the claims of the present invention and the equivalents thereof.
In the following description, “%” and “part” representing amounts are based on weight unless otherwise specified. Moreover, the following operation was performed in normal temperature normal pressure atmosphere unless otherwise indicated.

[Production Example 1. Production of circularly polarized light separating sheet]
25.5 parts of a compound represented by the following formula (X), 11 parts of a polymerizable liquid crystalline compound represented by the following formula (Y), 2.3 parts of a chiral agent (“LC756” manufactured by BASF), polymerization initiation Cholesteric liquid crystal was prepared by mixing 1.2 parts of an agent (“Irgacure OXE02” manufactured by Ciba Specialty Chemicals), 0.04 part of a surfactant (“Fuent 209F” manufactured by Neos) and 60 parts of cyclopentanone as a solvent. A composition was prepared.

  The compound represented by the above formula (X) was used according to the method described in Japanese Patent No. 5365519, and the compound represented by the above formula (Y) was used according to the method described in Japanese Patent No. 4054392. .

An alicyclic olefin resin film (“Zeonor Film” manufactured by Nippon Zeon Co., Ltd.) having a thickness of 130 μm was prepared as a substrate. One side of the substrate was rubbed, and the cholesteric liquid crystal composition was applied using a # 10 wire bar to obtain a cholesteric liquid crystal composition layer. This layer of cholesteric liquid crystal composition was subjected to alignment treatment at 130 ° C. for 5 minutes. Thereafter, a process comprising irradiation treatment with weak ultraviolet rays of 0.1 mJ / cm ^{2 to} 45 mJ / cm ² and subsequent heating treatment at 100 ° C. for 1 minute is repeated twice for the cholesteric liquid crystal composition layer. After that, an ultraviolet ray of 800 mJ / cm ² was irradiated in a nitrogen atmosphere to form a cholesteric resin layer having a thickness of 5.2 μm. As a result, a circularly polarized light separating sheet having a layer structure of cholesteric resin layer / base material was obtained.

  About the circularly polarized light separating sheet thus manufactured, a transmission spectrum is measured using a spectroscope (“instant multi-photometry system MCPD-3000” manufactured by Otsuka Electronics Co., Ltd.) and a microscope (“polarized microscope ECLIPSEE600-POL” manufactured by Nikon). did. As a result, the circularly polarized light separating sheet has a function of reflecting the right circularly polarized light in the selective reflection band in the visible light region and transmitting the other circularly polarized light, and the half width of the selective reflection band is 470 nm. Met.

[Production Example 2. Production of selective reflective screen]
On the cholesteric resin layer side of the circularly polarized light separating sheet as the selective light reflecting layer, a diffusion sheet as a light diffusion layer (“Light Control Film S012” manufactured by Yodogawa Paper Mill, thickness 50 μm, total light transmittance 99%, haze 86%) was bonded using a laminator through an adhesive. At this time, the thickness of the pressure-sensitive adhesive layer was 25 μm.

  Further, a black polyethylene terephthalate sheet (“Kukikiri Mierle” manufactured by Yodogawa Paper Mill) as a light absorbing layer was bonded to the base material side of the circularly polarized light separating sheet with a laminator through an adhesive. Thereby, a selective reflection screen was obtained as a projection surface member having a layer structure of diffusion sheet / adhesive layer / cholesteric resin layer / base material / adhesive layer / black polyethylene terephthalate sheet.

[Production Example 3. Manufacturing of circularly polarized illumination device]
As a non-polarized light source device that can emit non-polarized light, an LED desk stand (“SQ-LD200” manufactured by Panasonic) was prepared. The surface of the circularly polarized light separating sheet made of the cholesteric resin layer and the base material was bonded to the light emitting portion of the non-polarized light source device using an adhesive tape. As a result, a circularly polarized illumination device capable of supplying left circularly polarized light as the second light was obtained.

[Production Example 4. Manufacture of circularly polarized projector]
A linear polarizer and a quarter wave plate were bonded together to obtain a circularly polarizing plate having a function of converting non-polarized light into right circularly polarized light. In addition, a DLP type non-polarized light projection device (“PLUS U3-1100Z” manufactured by Plusvision) capable of projecting non-polarized light was prepared. The circularly polarizing plate was attached to the light projection portion of this non-polarized projection apparatus. As a result, a circularly polarized light projection device capable of projecting right circularly polarized light as the first light was obtained.

[Description of Example Group I]
Hereinafter, Examples and Comparative Examples in which illumination is installed in front of the screen and brightness is measured from substantially the front of the screen will be described.

[Example I-1]
In the dark room, the selective reflection screen manufactured in Production Example 2 was installed so that the projection surface on the diffusion sheet side of the selective reflection screen was a plane perpendicular to the horizontal direction. In addition, a non-polarization projector (plus) is provided at a point about 2 m away from the projection surface of the selective reflection screen in the front direction so that unpolarized light can be projected as the first light from the front direction onto the projection surface of the selective reflection screen. Vision Corporation “PLUS U3-1100Z”) was installed. Further, in order to be able to illuminate the projection surface of the selective reflection screen from the front direction, production example 3 is located immediately adjacent to the non-polarized projection device (that is, a point about 2 m away from the front direction of the projection surface of the selective reflection screen). The circularly polarized light illumination device manufactured in 1 was installed. Thus, an image projection system including a selective reflection screen as a projection surface member, a non-polarization projection device as a projection device, and a circularly polarized illumination device as a second light supply source was prepared.

  In this image projection system, a luminance meter (at a point about 2 m away in the polar angle 10 ° direction of the projection surface of the selective reflective screen (that is, a direction that forms an angle of 10 ° with respect to the normal direction of the projection surface). “SR-3” manufactured by TOPCON, measuring angle 2 °, measuring area Φ66.4 mm) was installed. An image including a white display part and a black display part by projecting non-polarized light from the non-polarization projection device onto the projection surface of the selective reflection screen while turning on the circular polarization illumination device and illuminating the selective reflection screen with left circular polarization. Was displayed. And the brightness | luminance of the white display part of this image and the brightness | luminance of the black display part were measured with the said luminance meter. Further, the contrast CR (the luminance of the white display portion / the luminance of the black display portion) was calculated by dividing the luminance of the white display portion by the luminance of the black display portion.

[Example I-2]
In order to use right circularly polarized light as the first light, the circularly polarized light projection device manufactured in Production Example 4 was used instead of the non-polarized light projection device. Except for the above, the image projection system was manufactured and evaluated in the same manner as in Example I-1.

[Comparative Example CI-1]
In order to use non-polarized light as the second light, a non-polarized light source device (an LED desk stand “SQ-LD200” manufactured by Panasonic) was used instead of the circularly polarized illumination device. Except for the above, the image projection system was manufactured and evaluated in the same manner as in Example I-1.

[Comparative Example CI-2]
In order to use right circularly polarized light as the first light, the circularly polarized light projection device manufactured in Production Example 4 was used instead of the non-polarized light projection device. Further, in order to use non-polarized light as the second light, a non-polarized light source device (an LED desk stand “SQ-LD200” manufactured by Panasonic) was used instead of the circularly polarized illumination device. Except for the above, the image projection system was manufactured and evaluated in the same manner as in Example I-1.

[Comparative Example CI-3]
Instead of the selectively reflective screen, white printing paper was used as the screen. Except for the above, the image projection system was manufactured and evaluated in the same manner as in Example I-1.

[Comparative Example CI-4]
In order to use right circularly polarized light as the first light, the circularly polarized light projection device manufactured in Production Example 4 was used instead of the non-polarized light projection device. Also, white printing paper was used as the screen instead of the selectively reflective screen. Except for the above, the image projection system was manufactured and evaluated in the same manner as in Example I-1.

[Comparative Example CI-5]
In order to use non-polarized light as the second light, a non-polarized light source device (an LED desk stand “SQ-LD200” manufactured by Panasonic) was used instead of the circularly polarized illumination device. Also, white printing paper was used as the screen instead of the selectively reflective screen. Except for the above, the image projection system was manufactured and evaluated in the same manner as in Example I-1.

[Comparative Example CI-6]
In order to use right circularly polarized light as the first light, the circularly polarized light projection device manufactured in Production Example 4 was used instead of the non-polarized light projection device. In addition, in order to use non-polarized light as the second light, a non-polarized light source device (LED desk stand “SQ-LD200” manufactured by Panasonic) was used instead of the circularly polarized illumination. Furthermore, instead of the selective reflective screen, white printing paper was used as the screen. Except for the above, the image projection system was manufactured and evaluated in the same manner as in Example I-1.

[Results of Examples I-1 to I-2 and Comparative Examples CI-1 to CI-6]
Table 1 shows the results of Examples I-1 to I-2 and Comparative Examples CI-1 to CI-6. In Table 1, the meanings of the abbreviations are as follows.
CR: Contrast CLC: Selective reflective screen Paper: Screen made of white printing paper

[Description of Example Group II]
Hereinafter, examples and comparative examples in which the illumination is installed in front of the screen and the luminance is measured from the tilt direction of the screen will be described.

[Examples II-1 to II-2 and Comparative Examples CII-1 to CII-6]
The position of the luminance meter was changed to a point about 2 m away in the polar angle 45 ° direction of the projection plane of the screen (that is, the direction forming an angle of 45 ° with respect to the normal direction of the projection plane). Except for the above, the image projection system was manufactured and evaluated in the same manner as in Examples I-1 to I-2 and Comparative Examples CI-1 to CI-6.

[Results of Examples II-1 to II-2 and Comparative Examples CII-1 to CII-6]
Table 2 shows the results of Examples II-1 to II-2 and Comparative Examples CII-1 to CII-6. In Table 2, the meaning of the abbreviation is the same as in Table 1.

[Description of Example Group III]
Hereinafter, Examples and Comparative Examples in which illumination is installed in the tilt direction of the screen and brightness is measured from substantially the front of the screen will be described.

[Examples III-1 to III-2 and Comparative Examples CIII-1 to CIII-6]
The position of the illumination (circularly polarized illumination device or non-polarized light source device) is about 2 m away in the polar angle 45 ° direction of the projection plane of the screen (ie, the direction that forms an angle of 45 ° with respect to the normal direction of the projection plane) It was changed to the point. Except for the above, the image projection system was manufactured and evaluated in the same manner as in Examples I-1 to I-2 and Comparative Examples CI-1 to CI-6.

[Results of Examples III-1 to III-2 and Comparative Examples CIII-1 to CIII-6]
Table 3 shows the results of Examples III-1 to III-2 and Comparative Examples CIII-1 to CIII-6. In Table 3, the meaning of the abbreviation is the same as in Table 1.

[Consideration]
As can be seen from the above table, in the above-described example, a higher contrast is obtained than in the comparative example. As can be seen from this result, according to the image projection system of the present invention, it is possible to display an image with high contrast even in a bright environment illuminated by the second light. Moreover, from the said Example, when non-polarized light was used as 1st light, it was confirmed that especially high contrast is obtained.

DESCRIPTION OF SYMBOLS 10 Image projection system 20 Image projection system 100 Projection surface member 100S Projection surface 110 Light diffusion layer 120 Selective light reflection layer 130 Light absorption layer 200 Projection device 300 Illumination device 400 Polarization transmission filter

Claims (6)

A projection surface member comprising a selective light reflective layer capable of selectively reflecting polarized light;
Projection device capable of projecting first light including polarized light that can be reflected by the selective light reflective layer onto the projection surface member and displaying an image by the reflected light of the first light from the selective light reflective layer When,
A second light source capable of illuminating the projection surface member with a second light,
The image projection system, wherein the second light is reversely polarized with respect to polarized light that is included in the first light and can be reflected by the selective light reflective layer. The polarized light that is included in the first light and can be reflected by the selective light reflective layer is one of left circularly polarized light and right circularly polarized light,
The image projection system according to claim 1, wherein the second light is the other of left circularly polarized light and right circularly polarized light.   The image projection system according to claim 1, wherein the selective light reflective layer includes a cholesteric resin layer.   The image projection system according to claim 1, wherein the projection surface member is a screen or a wall material.   The said projection surface member is equipped with the said selective light reflective layer and the light absorption layer which can absorb said 2nd light in this order from the one close | similar to the said projection apparatus in any one of Claims 1-4. Image projection system. A projection surface member for receiving the first light projected from the projection device to display an image while being illuminated by the second light supplied from the second light source;
The projection surface member includes a selective light reflective layer capable of selectively reflecting polarized light included in the first light,
The projection surface member, wherein the polarized light that is included in the first light and can be reflected by the selective light reflective layer, and the second light are oppositely polarized light.

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