JP6193471B2 - Projection video display member and projection video display member including projection video display member - Google Patents

Description

  The present invention relates to a projection image display member and a projection system including a projection image display member.

Many projectors in which the projection light contains polarized light are commercially available. As a projection screen used in combination with such a projector, a projection screen that selectively reflects only light in a specific polarization state has been proposed. It is possible to provide quality projected images (for example, Patent Document 1 and Patent Document 2).
When a layer having a fixed cholesteric liquid crystal phase is used as a projection screen as described in Patent Document 2, the amount of circularly polarized light obtained by reflecting linearly polarized light is theoretically reduced to half, so that efficient light reflection is possible. In addition, the linearly polarized light projected from the projector can be irradiated by being converted into circularly polarized light reflected by a layer having a fixed cholesteric liquid crystal phase by a quarter wavelength phase difference plate or the like. However, it is known that many of the projectors described above have a non-uniform polarization direction in the wavelength bands of red, green, and blue light in the projected light (Patent Document 3), and the projection light is ¼. The circularly polarized light obtained by the conversion with the wavelength phase difference plate does not have the same sense of circularly polarized light depending on the wavelength bands of red, green, and blue light (Patent Document 4).

JP-A 62-266980 JP-A-5-107660 JP 2000-212449 A JP 2006-208786 A

  An object of the present invention is to provide a projection image display member capable of providing a high-quality image. For example, for projection image display capable of providing a high-quality image even in a bright environment. It is to provide a member. Another object of the present invention is to provide a projection system including a projection image display member.

  In order to solve the above-mentioned problems, the present inventor diligently studied and focused on solving this problem by designing a layer formed from a cholesteric liquid crystal phase according to the polarization characteristics of the light projected from the projector. The present invention has been completed.

That is, the present invention provides the following [1] to [10].
[1] including at least three layers in which a cholesteric liquid crystal phase is fixed;
The layer having the three cholesteric liquid crystal phases fixed exhibits different center wavelengths of selective reflection,
The three-layer cholesteric liquid crystal phase-fixed layer includes a projection image display member including a layer in which the twist direction of the spiral of the cholesteric liquid crystal is on the right side and a layer on the left side.
[2] A layer in which a cholesteric liquid crystal phase having a central wavelength of selective reflection is fixed at 750 to 620 nm, a layer in which a cholesteric liquid crystal phase having a central wavelength of selective reflection is fixed at 630 to 500 nm, and a center of selective reflection at 530 to 420 nm The projection image display member according to [1], including a layer in which a cholesteric liquid crystal phase having a wavelength is fixed, and the central wavelengths of the selective reflection of the three layers differ from each other by 50 nm or more.

[3] The projection image display member according to [2], wherein the twisted direction of the spiral of the cholesteric liquid crystal between the layer in which the cholesteric liquid crystal phase having a central wavelength of selective reflection at 630 to 500 nm is fixed and the other two layers is opposite .
[4] The projected image display member according to any one of [1] to [3], which is a reflective member.
[5] The projected image display member according to any one of [1] to [4], wherein the haze value at a wavelength of 550 nm measured from any one of the surfaces is 2.0 or more.
[6] The projected image display member according to any one of [1] to [5], which is a screen that displays a projected image as a real image on the surface of the projected image display member.
[7] The projected image display member according to any one of [1] to [4], which is a half mirror having visible light permeability.
[8] The projected image display member according to [7], which is used as a combiner for a head-up display.
[9] A projection system including a projector that projects linearly polarized light, a wave plate that converts linearly polarized light into circularly polarized light, and the projection image display member according to any one of [1] to [8].
[10] The projection system according to [9], wherein the wave plate that converts linearly polarized light into circularly polarized light is a λ / 4 wavelength phase difference plate.

  According to the present invention, a projection image display member capable of providing a high-quality image is provided. In particular, the present invention provides a projection image display member capable of providing a high-quality image as a projection image display member for use in combination with a projector that projects linearly polarized light. The projection image display member of the present invention is suitable for use as a projection screen or a combiner for a head-up display.

It is a figure which shows arrangement | positioning of the projector, the quarter wavelength phase difference plate, a rear proscreen, and the member for a projection image display in the projection system used in the Example. It is a figure which shows arrangement | positioning of the projector, the quarter wavelength phase difference plate, and the member for a projection image display in the projection system used in the Example.

Hereinafter, the present invention will be described in detail.
In the present specification, “to” is used to mean that the numerical values described before and after it are included as a lower limit value and an upper limit value. Further, in the present specification, regarding the angle (for example, an angle such as “90 °”) and the relationship (for example, “orthogonal”, “parallel”, “crossing at 45 °”, etc.), the technical field to which the present invention belongs. The range of allowable error is included. For example, it means that the angle is within the range of strict angle ± 10 °, and the error from the strict angle is preferably 5 ° or less, and more preferably 3 ° or less.

In this specification, “selective” for circularly polarized light means that the amount of light of either the right circularly polarized component or the left circularly polarized component of the irradiated light is greater than that of the other circularly polarized component. Specifically, when referred to as “selective”, the degree of circular polarization of light is preferably 0.3 or more, more preferably 0.6 or more, and even more preferably 0.8 or more. More preferably, it is substantially 1.0. Table In _{/ (I R + I L)} | Here, the degree of circular polarization, the intensity of the right circularly polarized light component of the light I _R, when the strength of the left-handed circularly polarized light component and I _L, | I _R -I _L Is the value to be In this specification, the degree of circular polarization is sometimes used to represent the ratio of circularly polarized light components.

  In this specification, “sense” for circularly polarized light means right circularly polarized light or left circularly polarized light. The sense of circularly polarized light is right-handed circularly polarized light when the electric field vector tip turns clockwise as time increases when viewed as the light travels toward you, and left when it turns counterclockwise. Defined as being circularly polarized.

  In this specification, the term “sense” may be used for the twist direction of the spiral of the cholesteric liquid crystal. The selective reflection by the cholesteric liquid crystal reflects right circularly polarized light when the twist direction (sense) of the cholesteric liquid crystal spiral is right, transmits left circularly polarized light, and reflects left circularly polarized light when the sense is left, Transmits circularly polarized light.

In this specification, “light” means visible light (natural light) unless otherwise specified. Visible light is light having a wavelength that can be seen by human eyes among electromagnetic waves, and usually indicates light having a wavelength range of 380 nm to 780 nm.
In this specification, the measurement of the light intensity required in connection with the calculation of the light transmittance may be performed by using, for example, a normal visible spectrum meter and measuring the reference as air.
In the present specification, the term “reflected light” or “transmitted light” is used to mean scattered light and diffracted light.

In addition, the polarization state of each wavelength of light can be measured using a spectral radiance meter or a spectrometer equipped with a circularly polarizing plate. In this case, the intensity of light measured through the right circularly polarizing plate corresponds to I _R , and the intensity of light measured through the left circularly polarizing plate corresponds to I _L. In addition, ordinary light sources such as incandescent bulbs, mercury lamps, fluorescent lamps, and LEDs emit almost natural light. However, the characteristic of creating polarization of a measurement object such as a projection image display member mounted on these light sources is, for example, AXOMETRICS. It can be measured using a polarization phase difference analyzer AxoScan manufactured by the company.
The polarization state can also be measured by attaching a measurement object to an illuminometer or an optical spectrum meter. The ratio can be measured by attaching a right circular polarized light transmission plate, measuring the right circular polarized light amount, attaching a left circular polarized light transmission plate, and measuring the left circular polarized light amount.

<Projection image display member>
In this specification, the projection image display member may be any member that can display a projection image with reflected light or transmitted light, and can display the projection image projected from a projector or the like in a visible manner. Anything is acceptable. The projection image display member may be a reflection member. Examples of the projection image display member include a projection screen and a projection image display half mirror.

(Configuration of projection image display member)
The projection image display member of the present invention includes at least three layers in which a cholesteric liquid crystal phase is fixed.
In the present specification, a layer in which a cholesteric liquid crystal phase is fixed may be referred to as a cholesteric liquid crystal layer or a liquid crystal layer.
The projected image display member may include layers such as an antireflection layer, an alignment layer, a support, an adhesive layer, and a substrate described later in addition to the cholesteric liquid crystal layer.

  When the projection image display member is a projection screen that displays a projection image on the surface as a real image, the projection image display member may include a light blocking layer that reflects or absorbs light. Furthermore, an antireflection layer or a hard coat layer may be included on the surface side that is the outermost surface on the observation side. When the projection image display member is a half mirror that displays the projection image as a virtual image that appears above the projection image display member when viewed from the observer, it does not include a light blocking layer that reflects or absorbs light. Is preferred. This is to obtain high transparency (visible light transparency of 60% or more, preferably 70% or more) for visually recognizing the surrounding scenery or viewing information on the opposite side of the projection image display member.

  The projection image display member may be a thin film, sheet, or plate. The projected image display member may have a flat shape without a curved surface, but may have a curved surface, and has a concave or convex shape as a whole, and enlarges or reduces the projected image. May be displayed. Moreover, it may adhere to another member and become said shape, and before adhesion | attachment, it may be a roll shape etc. as a thin film.

(Cholesteric liquid crystal phase fixed layer: cholesteric liquid crystal layer)
The cholesteric liquid crystal layer functions as a circularly polarized light selective reflection layer that selectively reflects either right circularly polarized light or left circularly polarized light and transmits the other circularly polarized light in the selective reflection band (selective reflection wavelength range). . That is, the sense of reflected circularly polarized light is left if the sense of transmitted circularly polarized light is right, and is right if the sense of transmitted circularly polarized light is left. With the above function of the cholesteric liquid crystal layer, it is possible to form a projected image by reflecting the circularly polarized light of one of the senses at a wavelength showing selective reflection in the projection light.
Many films formed from a composition containing a polymerizable liquid crystal compound have been known as films exhibiting circularly polarized light selective reflectivity, and a layer in which a cholesteric liquid crystal phase is fixed (cholesteric liquid crystal layer) is known in the related art. You can refer to the technology.

  The cholesteric liquid crystal layer may be a layer in which the orientation of the liquid crystal compound in the cholesteric liquid crystal phase is maintained. Typically, the polymerizable liquid crystal compound is placed in the orientation state of the cholesteric liquid crystal phase and then irradiated with ultraviolet rays. Any layer may be used as long as it is polymerized and cured by heating or the like to form a layer having no fluidity, and at the same time, the layer is changed to a state in which the orientation is not changed by an external field or an external force. In the cholesteric liquid crystal layer, it is sufficient that the optical properties of the cholesteric liquid crystal phase are maintained in the layer, and the liquid crystal compound in this layer may no longer exhibit liquid crystallinity. For example, the polymerizable liquid crystal compound may have a high molecular weight due to a curing reaction and may no longer have liquid crystallinity.

The cholesteric liquid crystal layer exhibits circularly polarized reflection derived from the helical structure of cholesteric liquid crystal. In the present specification, this circularly polarized reflection is referred to as selective reflection.
The central wavelength λ of selective reflection depends on the pitch length P (= helical period) of the helical structure in the cholesteric phase, and follows the relationship between the average refractive index n of the cholesteric liquid crystal layer and λ = n × P. In the present specification, the selective reflection center wavelength λ of the cholesteric liquid crystal layer means the wavelength at the center of gravity of the reflection peak of the circularly polarized reflection spectrum measured from the normal direction of the cholesteric liquid crystal layer. As can be seen from the above equation, the center wavelength of selective reflection can be adjusted by adjusting the pitch length of the spiral structure. That is, by adjusting the n value and the P value, for example, to selectively reflect either the right circularly polarized light or the left circularly polarized light with respect to the blue light, the center wavelength λ is adjusted, and an apparent selection is made. The central wavelength of reflection can be in the wavelength range of 450 nm to 495 nm. The apparent center wavelength of selective reflection means the wavelength at the center of gravity of the reflection peak of the circularly polarized reflection spectrum of the cholesteric liquid crystal layer measured from the observation direction in practical use. Since the pitch length of the cholesteric liquid crystal phase depends on the kind of chiral agent used together with the polymerizable liquid crystal compound or the concentration of the chiral agent, the desired pitch length can be obtained by adjusting these. For the method of measuring spiral sense and pitch, use the methods described in “Introduction to Liquid Crystal Chemistry Experiments”, edited by the Japanese Liquid Crystal Society, Sigma Publishing 2007, page 46, and “Liquid Crystal Handbook”, Liquid Crystal Handbook Editing Committee, page 196. be able to.

As each cholesteric liquid crystal layer, a cholesteric liquid crystal layer whose spiral sense is either right or left is used. The sense of reflected circularly polarized light in the cholesteric liquid crystal layer coincides with the sense of a spiral.
The full width at half maximum Δλ (nm) of the selective reflection band exhibiting circularly polarized selective reflection follows the relationship of Δλ = Δn × P, where Δλ depends on the birefringence Δn of the liquid crystal compound and the pitch length P. Therefore, the width of the selective reflection band can be controlled by adjusting Δn. Δn can be adjusted by adjusting the kind of the polymerizable liquid crystal compound and the mixing ratio thereof, or by controlling the temperature at the time of fixing the alignment.
In order to form one type of cholesteric liquid crystal layer having the same central wavelength of selective reflection, a plurality of cholesteric liquid crystal layers having the same period P and the same spiral sense may be stacked. By laminating cholesteric liquid crystal layers having the same period P and the same spiral sense, the circularly polarized light selectivity can be increased at a specific wavelength.

  For example, in the visible light region, the width of the selective reflection band is usually about 15 nm to 100 nm for one material. In order to increase the width of the selective reflection band, two or more kinds of cholesteric liquid crystal layers having different center wavelengths of reflected light with different periods P may be stacked. At this time, it is preferable to stack cholesteric liquid crystal layers having the same spiral sense. In addition, the width of the selective reflection band can be increased by gradually changing the period P in the film thickness direction in one cholesteric liquid crystal layer. The width of the selective reflection band is not particularly limited, but may be a wavelength width such as 1 nm, 10 nm, 50 nm, 100 nm, 150 nm, or 200 nm. The width is preferably about 100 nm or less.

  The projection image display member of the present invention preferably includes a cholesteric liquid crystal layer having an apparent center wavelength of selective reflection for red light, green light, and blue light. Specifically, the projected image display member of the present invention has three central wavelengths of selective reflection that are different from each other (for example, 50 nm or more different) in the respective ranges of 750 to 620 nm, 630 to 500 nm, and 530 to 420 nm. It is also preferable to have it. This is because a full-color projected image can be displayed. Specifically, it may be configured to include three or more kinds of cholesteric liquid crystal layers having different periods P and hence different center wavelengths of selective reflection. Preferably, the projection image display member of the present invention has a cholesteric liquid crystal layer (selectively reflecting central wavelength at 750 to 620 nm) that selectively reflects either right circularly polarized light or left circularly polarized light with respect to red light. A cholesteric liquid crystal layer), a cholesteric liquid crystal layer (cholesteric liquid crystal layer having a central wavelength of selective reflection at 630 to 500 nm) that selectively reflects either right circularly polarized light or left circularly polarized light with respect to green light, and blue light On the other hand, it is preferable to include a cholesteric liquid crystal layer (cholesteric liquid crystal layer having a central wavelength of selective reflection at 530 to 420 nm) that selectively reflects either right circularly polarized light or left circularly polarized light.

  By adjusting the central wavelength of selective reflection of the cholesteric liquid crystal layer to be used according to the emission wavelength range of the light source used for projection and the usage mode of the projection image display member, a clear projection image is displayed with high light utilization efficiency. be able to. In particular, by adjusting the center wavelengths of selective reflection of a plurality of cholesteric liquid crystal layers in accordance with the emission wavelength range of the light source used for projection, it is possible to display a clear color projection image with light utilization efficiency. Examples of usage of the projection image display member include an incident angle of projection light on the surface of the projection image display member, a projection image observation direction on the surface of the projection image display member, and the like.

  A cholesteric liquid crystal layer including at least three layers in the projected image display member having different selective reflection center wavelengths includes a layer in which the twist direction (sense) of the spiral of the cholesteric liquid crystal is on the right side and a layer on the left side. When the projected image display member includes three cholesteric liquid crystal layers each having an apparent center wavelength of selective reflection with respect to red light, green light, and blue light, the twist direction is reversed in any layer. However, it is preferable that the twist directions of the spirals of the cholesteric liquid crystal layer having the central wavelength in green light and the other two layers are reversed. Specifically, it is preferable that the twist directions of the spirals of the cholesteric liquid crystal layer of the cholesteric liquid crystal layer having the center wavelength of selective reflection at 630 to 500 nm and the other two layers are reversed. As a result of confirmation by the present inventors, in many commercially available projectors, the green output light is different from the other output light (red light and blue light) in the polarization direction (transmission axis direction). The directions were orthogonal. Therefore, a projection image suitable for projection by projection light from a projector having the above characteristics with a configuration in which the twisting direction of the spiral of the cholesteric liquid crystal layer having a central wavelength in green light and the other two layers is reversed. It can be set as a display member.

  When laminating a plurality of cholesteric liquid crystal layers, a separately prepared cholesteric liquid crystal layer may be laminated using an adhesive or the like, and the polymerizable liquid crystal is directly applied to the surface of the previous cholesteric liquid crystal layer formed by the method described later. A liquid crystal composition containing a compound or the like may be applied and the alignment and fixing steps may be repeated, but the latter is preferred. By forming the next cholesteric liquid crystal layer directly on the surface of the previously formed cholesteric liquid crystal layer, the orientation direction of the liquid crystal molecules on the air interface side of the previously formed cholesteric liquid crystal layer and the cholesteric liquid crystal layer formed thereon This is because the orientation directions of the lower liquid crystal molecules coincide with each other, and the polarization property of the laminate of cholesteric liquid crystal layers is improved. In addition, when an adhesive layer that is normally provided with a film thickness of 0.5 to 10 μm is used, interference unevenness derived from the uneven thickness of the adhesive layer may be observed. It is because it is preferable.

(Method for producing a layer having a fixed cholesteric liquid crystal phase)
Hereinafter, a manufacturing material and a manufacturing method of the cholesteric liquid crystal layer will be described.
Examples of the material used for forming the cholesteric liquid crystal layer include a liquid crystal composition containing a polymerizable liquid crystal compound and a chiral agent (optically active compound). If necessary, apply the above liquid crystal composition, which is further mixed with a surfactant or polymerization initiator and dissolved in a solvent, onto a substrate (support, alignment film, underlying cholesteric liquid crystal layer, etc.), and then cholesteric. After the alignment aging, the cholesteric liquid crystal layer can be formed by fixing.

Polymerizable liquid crystal compound The polymerizable liquid crystal compound may be a rod-like liquid crystal compound or a disc-like liquid crystal compound, but is preferably a rod-like liquid crystal compound.
Examples of the rod-like polymerizable liquid crystal compound forming the cholesteric liquid crystal layer include a rod-like nematic liquid crystal compound. Examples of rod-like nematic liquid crystal compounds include azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, alkoxy-substituted phenylpyrimidines. , Phenyldioxanes, tolanes and alkenylcyclohexylbenzonitriles are preferably used. Not only low-molecular liquid crystal compounds but also high-molecular liquid crystal compounds can be used.

  The polymerizable liquid crystal compound can be obtained by introducing a polymerizable group into the liquid crystal compound. Examples of the polymerizable group include an unsaturated polymerizable group, an epoxy group, and an aziridinyl group, preferably an unsaturated polymerizable group, and particularly preferably an ethylenically unsaturated polymerizable group. The polymerizable group can be introduced into the molecule of the liquid crystal compound by various methods. The number of polymerizable groups possessed by the polymerizable liquid crystal compound is preferably 1 to 6, more preferably 1 to 3. Examples of polymerizable liquid crystal compounds are described in Makromol. Chem. 190, 2255 (1989), Advanced Materials 5, 107 (1993), US Pat. No. 4,683,327, US Pat. No. 5,622,648, US Pat. No. 5,770,107, International Publication WO95 / 22586. No. 95/24455, No. 97/00600, No. 98/23580, No. 98/52905, JP-A-1-272551, No. 6-16616, and No. 7-110469. 11-80081 and JP-A 2001-328773, and the like. Two or more kinds of polymerizable liquid crystal compounds may be used in combination. When two or more kinds of polymerizable liquid crystal compounds are used in combination, the alignment temperature can be lowered.

  Moreover, it is preferable that the addition amount of the polymeric liquid crystal compound in a liquid-crystal composition is 80-99.9 mass% with respect to solid content mass (mass except a solvent) of a liquid-crystal composition, and 85-99. More preferably, it is 5 mass%, and it is especially preferable that it is 90-99 mass%.

Chiral agent (optically active compound)
The chiral agent has a function of inducing a helical structure of a cholesteric liquid crystal phase. The chiral compound may be selected according to the purpose because the helical sense or helical pitch induced by the compound is different.
The chiral agent is not particularly limited, and known compounds (for example, liquid crystal device handbook, Chapter 3-4-3, TN, chiral agent for STN, page 199, Japan Society for the Promotion of Science, 142nd edition, 1989) Description), isosorbide, and isomannide derivatives can be used.
A chiral agent generally contains an asymmetric carbon atom, but an axially asymmetric compound or a planar asymmetric compound containing no asymmetric carbon atom can also be used as the chiral agent. Examples of the axial asymmetric compound or the planar asymmetric compound include binaphthyl, helicene, paracyclophane, and derivatives thereof. The chiral agent may have a polymerizable group. When both the chiral agent and the liquid crystal compound have a polymerizable group, they are derived from the repeating unit derived from the polymerizable liquid crystal compound and the chiral agent by a polymerization reaction between the polymerizable chiral agent and the polymerizable liquid crystal compound. A polymer having repeating units can be formed. In this aspect, the polymerizable group possessed by the polymerizable chiral agent is preferably the same group as the polymerizable group possessed by the polymerizable liquid crystal compound. Therefore, the polymerizable group of the chiral agent is also preferably an unsaturated polymerizable group, an epoxy group or an aziridinyl group, more preferably an unsaturated polymerizable group, and an ethylenically unsaturated polymerizable group. Particularly preferred.
The chiral agent may be a liquid crystal compound.

It is preferable that the chiral agent has a photoisomerizable group because a pattern having a desired reflection wavelength corresponding to the emission wavelength can be formed by irradiation with a photomask such as actinic rays after coating and orientation. As a photoisomerization group, the isomerization part of the compound which shows photochromic property, an azo, an azoxy, and a cinnamoyl group are preferable. Specific examples of the compound include JP 2002-80478, JP 2002-80851, JP 2002-179668, JP 2002-179669, JP 2002-179670, and JP 2002-2002. Use the compounds described in JP-A No. 179681, JP-A No. 2002-179682, JP-A No. 2002-338575, JP-A No. 2002-338668, JP-A No. 2003-313189, and JP-A No. 2003-313292. Can do.
The content of the chiral agent in the liquid crystal composition is preferably 0.01 mol% to 200 mol%, more preferably 1 mol% to 30 mol% of the amount of the polymerizable liquid crystal compound.

Polymerization initiator The liquid crystal composition preferably contains a polymerization initiator. In the embodiment in which the polymerization reaction is advanced by ultraviolet irradiation, the polymerization initiator to be used is preferably a photopolymerization initiator that can start the polymerization reaction by ultraviolet irradiation. Examples of the photopolymerization initiator include α-carbonyl compounds (described in US Pat. Nos. 2,367,661 and 2,367,670), acyloin ether (described in US Pat. No. 2,448,828), α-hydrocarbon substituted aromatics. Group acyloin compounds (described in US Pat. No. 2,722,512), polynuclear quinone compounds (described in US Pat. Nos. 3,046,127 and 2,951,758), combinations of triarylimidazole dimers and p-aminophenyl ketone (US patents) No. 3549367), acridine and phenazine compounds (JP-A-60-105667, US Pat. No. 4,239,850), oxadiazole compounds (US Pat. No. 4,221,970), and the like. .
The content of the photopolymerization initiator in the liquid crystal composition is preferably 0.1 to 20% by mass, and preferably 0.5 to 5% by mass with respect to the content of the polymerizable liquid crystal compound. Further preferred.

Crosslinking agent The liquid crystal composition may optionally contain a crosslinking agent in order to improve the film strength after curing and the durability. As the cross-linking agent, one that can be cured by ultraviolet rays, heat, moisture, or the like can be suitably used.
There is no restriction | limiting in particular as a crosslinking agent, According to the objective, it can select suitably, For example, polyfunctional acrylate compounds, such as a trimethylol propane tri (meth) acrylate and pentaerythritol tri (meth) acrylate; Glycidyl (meth) acrylate , Epoxy compounds such as ethylene glycol diglycidyl ether; aziridine compounds such as 2,2-bishydroxymethylbutanol-tris [3- (1-aziridinyl) propionate], 4,4-bis (ethyleneiminocarbonylamino) diphenylmethane; hexa Isocyanate compounds such as methylene diisocyanate and biuret type isocyanate; polyoxazoline compounds having an oxazoline group in the side chain; vinyltrimethoxysilane, N- (2-aminoethyl) 3-aminopropylto Alkoxysilane compounds such as methoxy silane. Moreover, a well-known catalyst can be used according to the reactivity of a crosslinking agent, and productivity can be improved in addition to membrane strength and durability improvement. These may be used individually by 1 type and may use 2 or more types together.
3 mass%-20 mass% are preferable, and, as for content of a crosslinking agent, 5 mass%-15 mass% are more preferable. When the content of the crosslinking agent is less than 3% by mass, the effect of improving the crosslinking density may not be obtained. When the content exceeds 20% by mass, the stability of the cholesteric liquid crystal layer may be decreased.

Alignment control agent In the liquid crystal composition, an alignment control agent that contributes to stably or rapidly forming a planar cholesteric liquid crystal layer may be added. Examples of the orientation control agent include fluorine (meth) acrylate polymers described in paragraphs [0018] to [0043] of JP-A-2007-272185, and paragraphs [0031] to [0034] of JP-A-2012-203237. Etc.] and the compounds represented by the formulas (I) to (IV).
In addition, as an orientation control agent, 1 type may be used independently and 2 or more types may be used together.

  The addition amount of the alignment control agent in the liquid crystal composition is preferably 0.01% by mass to 10% by mass, more preferably 0.01% by mass to 5% by mass with respect to the total mass of the polymerizable liquid crystal compound. 0.02% by mass to 1% by mass is particularly preferable.

Other additives In addition, the liquid crystal composition contains at least one selected from various additives such as a surfactant for adjusting the surface tension of the coating film and making the film thickness uniform, and a polymerizable monomer. It may be. Further, in the liquid crystal composition, if necessary, a polymerization inhibitor, an antioxidant, an ultraviolet absorber, a light stabilizer, a colorant, metal oxide fine particles, and the like may be added as long as the optical performance is not deteriorated. Can be added.

  A cholesteric liquid crystal layer is prepared by preparing a liquid crystal composition in which a polymerizable liquid crystal compound and a polymerization initiator, a chiral agent added as necessary, a surfactant, and the like are dissolved in a solvent, a support, an alignment layer, or first. The cholesteric liquid crystal layer is coated on the cholesteric liquid crystal layer and dried to obtain a coating film. The coating film is irradiated with actinic rays to polymerize the cholesteric liquid crystal composition. Can be formed. Note that a laminated film including a plurality of cholesteric liquid crystal layers can be formed by repeatedly performing a manufacturing process of the cholesteric liquid crystal layer.

There is no restriction | limiting in particular as a solvent used for preparation of a liquid-crystal composition, Although it can select suitably according to the objective, An organic solvent is used preferably.
The organic solvent is not particularly limited and may be appropriately selected depending on the intended purpose. For example, ketones, alkyl halides, amides, sulfoxides, heterocyclic compounds, hydrocarbons, esters, ethers, etc. Is mentioned. These may be used individually by 1 type and may use 2 or more types together. Among these, ketones are particularly preferable in consideration of environmental load.

  The method of applying the liquid crystal composition on the substrate is not particularly limited and can be appropriately selected depending on the purpose. For example, the wire bar coating method, curtain coating method, extrusion coating method, direct gravure coating method, reverse Examples include gravure coating, die coating, spin coating, dip coating, spray coating, and slide coating. Moreover, it can implement also by transferring the liquid-crystal composition separately coated on the support body to a base material. The liquid crystal molecules are aligned by heating the applied liquid crystal composition. The heating temperature is preferably 200 ° C. or lower, and more preferably 130 ° C. or lower. By this alignment treatment, an optical thin film in which the polymerizable liquid crystal compound is twisted and aligned so as to have a helical axis in a direction substantially perpendicular to the film surface is obtained.

The aligned liquid crystal compound may be further polymerized. The polymerization may be either thermal polymerization or photopolymerization by light irradiation, but photopolymerization is preferred. It is preferable to use ultraviolet rays for light irradiation. The irradiation energy is preferably ^{20mJ / cm 2 ~50J / cm 2} , 100mJ / cm 2 ~1,500mJ / cm 2 is more preferable. In order to accelerate the photopolymerization reaction, light irradiation may be performed under heating conditions or in a nitrogen atmosphere. The irradiation ultraviolet wavelength is preferably 350 nm to 430 nm. The polymerization reaction rate is preferably as high as possible from the viewpoint of stability, preferably 70% or more, and more preferably 80% or more. The polymerization reaction rate can determine the consumption rate of a polymerizable functional group using an IR absorption spectrum.
The film thickness of the cholesteric liquid crystal layer may be 1 μm to 20 μm, preferably 2 μm to 15 μm, and more preferably 3 μm to 10 μm.

(Support)
The support is not particularly limited. The support used for forming the cholesteric liquid crystal layer may be a temporary support that is peeled off after forming the cholesteric liquid crystal layer. When the support is a temporary support, it is not a layer constituting the projected image display member of the present invention, and there is no particular limitation on optical properties such as transparency and refraction. As the support (temporary support), glass or the like may be used in addition to the plastic film. Examples of the plastic film include polyester such as polyethylene terephthalate (PET), polycarbonate, acrylic resin, epoxy resin, polyurethane, polyamide, polyolefin, cellulose derivative, and silicone.
The film thickness of the support may be about 5 μm to 1000 μm, preferably 10 μm to 250 μm, more preferably 15 μm to 90 μm.

(Alignment film)
The alignment film is a layer having an organic compound, a rubbing treatment of a polymer (resin such as polyimide, polyvinyl alcohol, polyester, polyarylate, polyamide imide, polyether imide, polyamide, modified polyamide), oblique deposition of an inorganic compound, or a micro groove. Or accumulation of organic compounds (eg, ω-tricosanoic acid, dioctadecylmethylammonium chloride, methyl stearylate) by the Langmuir-Blodgett method (LB film). Furthermore, an alignment film in which an alignment function is generated by application of an electric field, application of a magnetic field, or light irradiation is also known.
In particular, the alignment film made of a polymer is preferably subjected to a rubbing treatment and then a composition for forming a liquid crystal layer is applied to the rubbing treatment surface. The alignment film to be formed is particularly preferable. The rubbing treatment can be performed by rubbing the surface of the polymer layer several times in a certain direction with paper or cloth.
You may apply | coat a liquid-crystal composition to the support body surface without providing an alignment film, or the surface which carried out the rubbing process of the support body.
When the support is a temporary support, the alignment film does not have to be peeled off together with the temporary support to form a layer constituting the projected image display member of the present invention.
The thickness of the alignment layer is preferably 0.01 to 5 μm, and more preferably 0.05 to 2 μm.

(Antireflection layer)
The projection image display member may include an antireflection layer. The antireflection layer may be provided on the observation side surface (outermost surface) as viewed from the cholesteric liquid crystal layer, and may be provided on the surface of the base material described later, on the opposite side of the surface on which the cholesteric liquid crystal layer is provided. Also good.
The antireflection layer is not particularly limited as long as it has practically sufficient durability and heat resistance, and can suppress the reflectance at 60 ° incidence to 5% or less, and is appropriately selected according to the purpose. For example, in addition to a film having fine surface irregularities, a two-layer film structure combining a high refractive index film and a low refractive index film, a medium refractive index film, a high refractive index film, and a low refractive index For example, a three-layer film structure in which rate films are sequentially stacked.

As a configuration example, two layers of a high refractive index layer / low refractive index layer or three layers having different refractive indexes are arranged in order from the bottom, and a medium refractive index layer (having a higher refractive index than the lower layer and a high refractive index). In some cases, a layer having a lower refractive index than a layer) / a layer having a higher refractive index / a layer having a lower refractive index are stacked in this order. Among them, from the viewpoint of durability, optical characteristics, cost, productivity, etc., it is preferable to have a medium refractive index layer / high refractive index layer / low refractive index layer in this order on the hard coat layer. Examples include the configurations described in JP-A-8-110401, JP-A-10-300902, JP-A 2002-243906, JP-A 2000-11706, and the like. Further, an antireflection film having a three-layer structure excellent in robustness against film thickness fluctuation is described in JP-A-2008-262187. Further, each layer may be provided with other functions, for example, an antifouling low refractive index layer, an antistatic high refractive index layer, an antistatic hard coat layer, an antiglare hard coat layer, and the like. (For example, JP-A-10-206603, JP-A-2002-243906, JP-A-2007-264113, etc.) and the like.
The refractive index of the high refractive index layer is preferably 1.65 to 2.20, and more preferably 1.70 to 1.80. The refractive index of the middle refractive index layer is adjusted to be a value between the refractive index of the low refractive index layer and the refractive index of the high refractive index layer. The refractive index of the medium refractive index layer is preferably 1.55 to 1.65, and more preferably 1.58 to 1.63.
Although the film thickness of an antireflection layer is not specifically limited, What is necessary is just about 0.1-10 micrometers, 1-5 micrometers, and 2-4 micrometers.

(Base material)
In the present specification, the base material means a layer provided for maintaining the shape of the cholesteric liquid crystal layer, and may be the same as the support used in forming the cholesteric liquid crystal layer. May be provided separately.
When the projected image display member of the present invention is used as a projected image display half mirror, the substrate is preferably transparent in the visible light region.
The projection image display member may or may not include a substrate. For example, the projection image display member is attached to at least a part of another article such as a windshield of a vehicle, and at least one of the articles is displayed. The part may function as a base material.

As the substrate, the same materials as those mentioned as examples of the support can be used. Moreover, as a film thickness of a base material, although the same film thickness as said support body may be sufficient, it may be larger than 1000 micrometers and may be 10 mm or more. Moreover, what is necessary is just 200 mm or less, 100 mm or less, 80 mm or less, 60 mm or less, 50 mm or less, 40 mm or less, 30 mm or less, 20 mm or less.
In the projected image display member, it is sufficient that the cholesteric liquid crystal layer is provided on one side of the base material, and it is preferable that the cholesteric liquid crystal layer is not provided on the other side.
Specific examples of polymer resin materials that can be used as a substrate include acrylic resins (such as acrylic esters such as polymethyl (meth) acrylate), polycarbonate, cyclic polyolefins such as cyclopentadiene-based polyolefins and norbornene-based polyolefins, and polypropylene. Examples include polyolefins, aromatic vinyl polymers such as polystyrene, polyarylate, and cellulose acylate.

(Adhesive layer)
The adhesive layer may be formed from an adhesive.
Adhesives include hot melt type, thermosetting type, photocuring type, reactive curing type, and pressure-sensitive adhesive type that does not require curing, from the viewpoint of curing method, and the materials are acrylate, urethane, urethane acrylate, epoxy , Epoxy acrylate, polyolefin, modified olefin, polypropylene, ethylene vinyl alcohol, vinyl chloride, chloroprene rubber, cyanoacrylate, polyamide, polyimide, polystyrene, polyvinyl butyral, etc. can do. From the viewpoint of workability and productivity, the photocuring type is preferable as the curing method, and from the viewpoint of optical transparency and heat resistance, it is preferable to use an acrylate, urethane acrylate, epoxy acrylate, or the like material.
The thickness of the adhesive layer may be 0.5 to 10 μm, preferably 1 to 5 μm. In order to reduce color unevenness and the like of the projected image display half mirror, it is preferably provided with a uniform film thickness.

(Projection screen)
When the projection image display member is used as a projection screen for displaying a real image on the member, the screen is preferably scattered and reflected with respect to the projection light wavelength in order to form a real image on the screen. If the scattering is small, the viewing angle is narrowed. Conversely, if the scattering is too large, the contrast of the display is lowered due to the scattering of ambient light. Therefore, it is preferable that the haze value measured from either surface of the projection image display member is 2.0% or more and 30% or less. When the haze value is 2.0% or more, light can be diffusely reflected on the surface of the projection image display member, and the projection image can be displayed with a wide viewing angle. Moreover, it becomes possible to suppress the contrast fall of the display image by ambient light because it is 30% or less. The haze value is more preferably 3.0% or more and 25% or less, and further preferably 4.0% or more and 20% or less.
In this specification, the haze value is {(scattering reflectance of natural light) / (scattering reflectance of natural light + regular reflectance of natural light) × 100 (%)}. The specular photometer is a spectrophotometer, and the specular reflectivity that can be measured by combining the spectrophotometer with an integrating sphere unit is the specular spectrophotometer. That's fine. The scattering reflectance can be calculated by subtracting the regular reflectance from the all-angle measurement value of the reflectance.
The haze value can be measured using a haze meter NDH-2000 manufactured by Nippon Denshoku.

The scattering reflection performance is obtained by, for example, a method of forming a diffusion layer formed by mixing fine particles in a binder and coating the transparent medium on the light incident side of the screen, or a method of disturbing the uniformity of the orientation of the cholesteric liquid crystal layer. Can be granted.
As an example of a method for disturbing the uniformity of alignment of the cholesteric liquid crystal layer, the polymerizable liquid crystal compound molecules in the liquid crystal composition provided on the surface of the cholesteric liquid crystal layer as a lower layer to which the liquid crystal composition is applied are formed. On the other hand, there is a method using a transparent layer made of a material that gives a low pretilt angle. As such a transparent layer, for example, a non-liquid crystalline polymerizable composition containing (meth) acrylate monomer, gelatin, urethane monomer or the like is applied and cured, polyimide (Nisan Chemical's polyimide varnish Sunever 130, etc.) And resins such as polyvinyl alcohol, polyester, polyarylate, polyamide imide, polyether imide, polyamide, and modified polyamide. The surface of the transparent layer to which the liquid crystal composition is applied is subjected to rubbing treatment (for example, rubbing treatment by rubbing the surface of the polymer layer with paper or cloth in a certain direction) in order to form a scattering reflective cholesteric liquid crystal layer. It is preferable not to do so.

The thickness of the layer is preferably 0.01 to 50 μm, and more preferably 0.05 to 20 μm.
For example, an acrylic layer obtained by applying and curing a layer containing a (meth) acrylate monomer is isotropic in the plane. Therefore, if a liquid crystal layer is formed without rubbing the acrylic layer surface, the acrylic layer is in contact with the acrylic layer. The in-plane orientation direction of the liquid crystal is random. Therefore, a cholesteric liquid crystal layer formed by applying a liquid crystal composition on the surface of the acrylic layer can be used as a layer having an alignment defect, and scattering reflectivity can be imparted.

In the present specification, the “tilt angle” means an angle formed by tilted liquid crystal molecules with a layer plane, and the maximum refractive index direction of the refractive index ellipsoid of the liquid crystal compound with respect to the layer plane is the maximum. Means the angle. Therefore, in the rod-like liquid crystal compound having positive optical anisotropy, the tilt angle means an angle formed by the major axis direction of the rod-like liquid crystal compound, that is, the director direction and the layer plane. The pretilt angle means the tilt angle of the liquid crystal molecules on the lower surface when the polymerizable liquid crystal compound is aligned in the formation of the cholesteric liquid crystal layer. The pretilt angle is preferably distributed in the range of 0 to 20 degrees. More preferably, it is distributed in the range of 0 to 10 degrees.
In the present specification, the term “liquid crystal molecule” means a molecule of a polymerizable liquid crystal compound in the liquid crystal composition, and when the polymerizable liquid crystal compound is polymerized by a curing reaction of the liquid crystal composition, the above-described polymerizable property. This means a partial structure corresponding to a liquid crystal compound molecule.

  In order to lower the pretilt angle as described above, preferably horizontal, and to reduce the alignment uniformity of the liquid crystal molecules, the transparent layer on which the liquid crystal composition is applied and the alignment treatment such as rubbing are not performed on the surface of the support. It is preferable. In order to make the liquid crystal molecules on the air interface side of the cholesteric liquid crystal layer horizontal, it is preferable to use the above-mentioned alignment control agent in the liquid crystal composition.

(Half mirror for projected image display)
The projected image display half mirror is capable of displaying the projected image so as to be visible, and information or landscape on the opposite side of the projected image display half mirror from the same surface on which the image is displayed. Means an optical member that can be observed simultaneously. That is, the projected image display half mirror can achieve a function as an optical path combiner that displays the ambient light and the image light in a superimposed manner.
Specific examples of use as a projected image display half mirror include a head-up display (HUD) combiner and a reflective mirror used in a projection device, a reflective screen for a see-through display, a reflective mirror for a head-mounted display, a dichroic mirror, etc. And flat mirrors, concave mirrors, convex mirrors and the like for forming virtual images by various projectors. Regarding the use of the head-up display as a combiner, JP 2013-79930 A and International Publication WO 2005/124431 can be referred to.
When the projected image display member is used as a projected image display half mirror, the haze value at a wavelength of 550 nm measured from either surface of the projected image display member is preferably less than 2.0%.

<Projection system>
The projection image display member can be a projection system for displaying a projection image together with a projector that projects linearly polarized light and a wave plate that converts linearly polarized light into circularly polarized light.
The projected image may be an image based on the projection of light from the projector to be used, not the surrounding scenery. The projected image may be a multicolor or full color image. The projected image may be formed from reflected light or transmitted light from the projected image display member, but is preferably formed from reflected light. The projected image may be displayed on the surface of the projected image display member and viewed as if it is displayed on the surface, and is a virtual image that appears above the projected image display member as viewed by the observer. It may be. When the projected image display member is a half mirror, it can be displayed as such a virtual image.

In the projection system, the projector, the wave plate that converts linearly polarized light into circularly polarized light, and the projection image display member may be arranged in this order. The wave plate may be integrated with the projector, may be integrated with the projection image display member, or may be separated from both.
In the projection system, the wave plate is installed at an angle at which the slow axis direction is adjusted in accordance with the polarization direction of the projection light of the projector and the outgoing light is circularly polarized. Furthermore, it arrange | positions so that the circular polarization sense of the projection light of each wavelength which permeate | transmitted the wavelength plate may match the selective reflection characteristic of the circular polarization of the projection image display member.

(Wave plate that converts linearly polarized light into circularly polarized light)
An example of a wave plate that converts linearly polarized light into circularly polarized light is a retardation plate that functions as a quarter wave plate. Examples of the quarter-wave plate include a one-quarter-type quarter-wave retardation plate, a broadband quarter-wave retardation plate in which a quarter-wave retardation plate and a half-wave retardation plate are stacked, and the like. Can be mentioned.
The front phase difference of the former λ / 4 wavelength phase difference plate may be a length of ¼ of the projection light wavelength. Therefore, for example, when the center wavelength of the projection light is 450 nm, 530 nm, and 640 nm, the wavelength of 450 nm is 112.5 nm ± 10 nm, preferably 112.5 nm ± 5 nm, more preferably 112.5 nm, and 530 nm. Inverse dispersion phase difference of 5 nm ± 10 nm, preferably 132.5 nm ± 5 nm, more preferably 132.5 nm, 160 nm ± 10 nm at a wavelength of 640 nm, preferably 160 nm ± 5 nm, more preferably 160 nm Although the plate is most preferable as the λ / 4 wavelength phase difference plate, a phase difference plate having a small wavelength dispersion of retardation or a forward dispersion phase difference plate can also be used. The reverse dispersion means a property that the absolute value of the phase difference becomes larger as the wavelength becomes longer, and the forward dispersion means a property that the absolute value of the phase difference becomes larger as the wavelength becomes shorter.

The latter laminated type quarter-wave retardation plate is formed by laminating a quarter-wave retardation plate and a half-wave retardation plate at an angle of about 60 degrees with respect to the slow axis. By arranging the retardation plate side on the incident side of the linearly polarized light and crossing the slow axis of the half-wave retardation plate at 15 degrees or 75 degrees with respect to the polarization plane of the incident linearly polarized light, It converts to circularly polarized light. Since the reverse dispersion of the phase difference is good, it can be suitably used.
The phase difference can be measured using a polarization phase difference analyzer AxoScan manufactured by AXOMETRIC. Alternatively, KOBRA 21ADH or WR (manufactured by Oji Scientific Instruments) may be measured by making light having a wavelength λ nm incident in the normal direction of the film.

  The λ / 4 wavelength retardation plate may be a commercially available product using a birefringent material such as quartz, or may be formed by arranging and fixing a polymerizable liquid crystal compound or a polymer liquid crystal compound. The type of liquid crystal compound used for this formation is not particularly limited. For example, an optically anisotropic layer obtained by forming a low-molecular liquid crystal compound in a nematic alignment in a liquid crystal state and then fixing by photocrosslinking or thermal cross-linking, or a polymer liquid crystal compound in a nematic alignment in a liquid crystal state and then cooling. Accordingly, an optically anisotropic layer obtained by fixing the orientation can also be used.

(projector)
As the projector, a projector that can project linearly polarized light may be used. Any projector may be used as long as it projects linearly polarized light on the principle of forming a projected image. The projector may be a projector that projects only linearly polarized light, or may be a projector that projects natural light or light in another polarization state together with linearly polarized light. In the present specification, the “projector” is “an apparatus that projects light or an image”, and includes an “apparatus that projects a drawn image onto a projection image display member”. In the present specification, a screen for displaying an image drawn by a projector may be referred to as an “intermediate image screen” separately from the projection image display member. The projector may, for example, enlarge and project an image drawn on a small intermediate image screen onto the projection image display member.

The projector is not particularly limited as long as it has a function of projecting an image. As an example of the projector, a projector having a configuration in which polarization is separated for each color by a polarization beam splitter or the like can be given. Specifically, a liquid crystal projector, a LCOS (Liquid Crystal on Silicon) projector, a CRT (Cathode Ray Tube) projector, and the like can be given.
In particular, the projector is preferably one in which the polarization directions of the wavelengths of emitted light are not all the same. In the projection system, the twist direction of the cholesteric liquid crystal layer may be adjusted according to the polarization direction of the light emitted from the projector.
As a light source of the projector, a laser light source, an LED, a discharge tube, or the like can be used.

(Intermediate image screen)
The projection system may include an intermediate image screen. It is only necessary that an image is drawn on the intermediate image screen. The intermediate image screen may be disposed between the projector and the projection image display member, and may be disposed between the λ / 4 wavelength phase difference plate and the projection image display member. The intermediate image screen may be a constituent member of the projector, or may be disposed independently between the projector and the projection image display member.

Examples of the intermediate image screen include a scattering film, a microlens array, and a screen for rear projection. When a plastic material is used as the intermediate image screen, if the intermediate image screen has birefringence, the polarization plane and light intensity of the polarized light incident on the intermediate image screen are disturbed, and color unevenness or the like occurs in the projected image display member. Although this tends to occur, the use of a retardation film having a predetermined phase difference can reduce the problem of color unevenness.
It is preferable that the intermediate image screen has a function of spreading and transmitting incident light, and can enlarge the viewing angle of the projected image on the projected image display member. For example, a screen composed of a microlens array can be mentioned. The microarray lens used in the head-up display is described in, for example, Japanese Patent Application Laid-Open No. 2012-226303, Japanese Patent Application Laid-Open No. 2010-145745, and Japanese Patent Application Publication No. 2007-523369.

  The present invention will be described more specifically with reference to the following examples. The materials, reagents, amounts and ratios of substances, operations, and the like shown in the following examples can be appropriately changed without departing from the gist of the present invention. Therefore, the scope of the present invention is not limited to the following examples.

<Production of Projected Image Display Member 1>
On a PET film manufactured by Fujifilm Co., Ltd. that has been rubbed, apply a wire bar at room temperature so that the coating liquid R-1 having the right twist direction shown in Table 1 has a dry film thickness of 5 μm after drying. Applied. The coating layer was dried at room temperature for 30 seconds, heated in an atmosphere of 85 ° C. for 2 minutes, and then irradiated with UV light at 30 ° C. with a fusion D bulb (lamp 90 mW / cm) at an output of 60% for 6 to 12 seconds. A liquid crystal layer was obtained. On this liquid crystal layer, the coating liquid L-2 with the twist direction shown on the left shown in Table 1 was applied at room temperature so that the dry film thickness after drying was 5 μm, and then dried, heated and irradiated with UV in the same manner as described above. And a second liquid crystal layer was formed. Further, the coating liquid R-3 having the right twist direction shown in Table 1 is applied onto the liquid crystal layer at room temperature so that the thickness of the dried film after drying is 5 μm. Irradiation was performed to form a third liquid crystal layer to obtain a reflective film.

The reflection peak of this projection image display member is at three wavelengths, and the respective center wavelengths measured using AxoScan manufactured by AXOMETRICS were 655 nm, 540 nm, and 465 nm. Moreover, the haze measured using Nippon Denshoku Co., Ltd. haze meter NDH2000 was 0.3.
Next, on the surface of the reflective film prepared above on the liquid crystal layer side, a UV curable adhesive Exp. U12034-6 was applied using a wire bar at room temperature so that the dry film thickness after drying was 5 μm. The coated surface and the surface of a 10 cm square 5 mm thick acrylic transparent substrate were bonded together so as not to contain air bubbles, and a fusion D bulb (lamp 90 mW / cm) at 30 ° C. with an output of 60% and 6%. UV irradiation for -12 seconds. Then, the Fuji Film Co., Ltd. PET, which was a support for the projected image display member, was peeled off to obtain a projected image display member 1 for HUD.

<Production of Projected Image Display Member 2>
The coating liquid R-1 is changed to the left L-1 in the twist direction, the coating liquid L-2 is changed to the right R-2, and the coating liquid R-3 is changed to the left L-3 in the twist direction. Similarly to the production of the projection image display member 1, the projection image display member 2 for HUD was obtained. The reflection peak of this projection image display member was at three wavelengths, and the respective central wavelengths measured in the same manner as in the production of the projection image display member 1 were 655 nm, 540 nm, and 465 nm. The haze was 0.3.

<Production of Projected Image Display Member 3>
The coating liquid A shown in Table 2 was applied to a PET surface manufactured by FUJIFILM Corporation using a wire bar at room temperature so that the dry film thickness after drying was 8 μm. The coating layer was dried at room temperature for 30 seconds, heated in an atmosphere of 85 ° C. for 2 minutes, and then irradiated with UV light at 30 ° C. with a fusion D bulb (lamp 90 mW / cm) at an output of 60% for 6 to 12 seconds. An acrylic layer (horizontal random alignment film, the above transparent layer) was formed. On this acrylic layer, without applying rubbing treatment, the coating liquid R-3 having the right twist direction shown in Table 1 was applied at room temperature so that the dry film thickness after drying was 5 μm, and then the same as described above. Drying, heating, and UV irradiation were performed to obtain a liquid crystal layer. If a liquid crystal layer is further formed on the liquid crystal layer having alignment defects, the liquid crystal layer similarly has alignment defects. Therefore, the thickness of the dry film after drying the coating liquid L-2 shown in Table 1 on this liquid crystal layer is The coating was applied at room temperature so as to have a thickness of 5 μm, followed by drying, heating and UV irradiation in the same manner as described above to form a second liquid crystal layer. Further, coating liquid R-1 shown in Table 1 whose twist direction is on the right is applied onto this liquid crystal layer at room temperature so that the thickness of the dried film after drying is 5 μm, and thereafter drying, heating, and UV are performed in the same manner as described above. Irradiation was performed to form a third liquid crystal layer to obtain a projected image display member 3 for a screen.
The reflection peak of this projection image display member is at three wavelengths, and the respective center wavelengths measured using AxoScan manufactured by AXOMETRICS were 655 nm, 540 nm, and 465 nm. The haze was 8.8.

<Preparation of Projected Image Display Member 4>
A projection image display member 4 for HUD was obtained in the same manner as the production of the projection image display member 1 except that the coating liquid L-2 was changed to R-2 with the twist direction on the right. The reflection peak of the projected image display member 4 was at 3 wavelengths, and the central wavelengths measured in the same manner as in the examples were 655 nm, 540 nm, and 465 nm. The haze was 0.2.
<Production of Projected Image Display Member 5>
A projection image display member 5 for a screen was obtained in the same manner as in the production of the projection image display member 3 except that the coating liquid L-2 was changed to a coating solution having a twist direction R-2 on the right. The projected image display member had a reflection peak at three wavelengths, and the center wavelengths measured in the same manner as in the examples were 655 nm, 540 nm, and 465 nm. The haze was 8.7.
Table 3 shows the structures and optical characteristics of the projection image display members 1 to 5 produced as described above.

<Production of projection system>
Example 1
A laser projector VPL-FHZ55 manufactured by Sony Corporation was prepared as a projection device. When the polarization state of this projection light was confirmed using a bandpass filter and an absorption type linear polarization plate, red light, green light, and blue light were all linearly polarized, and the polarization planes of red and blue light were parallel, and green light. It was confirmed that the plane of polarization of each was orthogonal to them. A film holder was attached to the tip of the lens of this projector, and Pure Ace WR W-142, which is a λ / 4 wavelength phase difference plate manufactured by Teijin Ltd., was installed. At this time, the slow axis of the λ / 4 plate was set in a 45 ° clockwise direction with respect to the polarization plane of the red light when the light emitted from the projector was observed. Further, FIG. 1 shows a virtual image obtained by projecting an image onto a rear-pro screen RHD-HCR manufactured by Kikuchi Science Laboratory Co., Ltd. as a real image forming screen and reflecting the image on the projection image display member 1. The projection system of Example 1 shown was made.

Example 2
The direction of the slow axis of the λ / 4 wavelength phase difference plate is set at an angle of 45 degrees counterclockwise with respect to the polarization plane of the red light when the light emitted from the projector is viewed. A projection system of Example 2 was produced in the same manner as Example 1 except that the projection image display member 2 was used instead.

Example 3
An EB-W18 liquid crystal projector manufactured by EPSON was prepared as a projection device. When the polarization state of this projection light was confirmed using a bandpass filter and an absorption linear polarization plate, red light, green light, and blue light were all linearly polarized, and the polarization planes of red and blue light were parallel, and green light It was confirmed that the plane of polarization of each was orthogonal to them. In the same manner as in Example 1, a λ / 4 wavelength phase difference plate was installed at the tip of the projector lens. A projection system of Example 3 shown in FIG. 2 was produced in which the image of the projector was projected onto the projection image display member 3 to view the real image.

Example 4
A projection system of Example 4 was produced in the same manner as Example 3 except that an Avio multi-projector MP-50 manufactured by Nippon Avionics was used as the projector. When the polarization state of this projector was confirmed in the same manner as in Example 1, all of red light, green light, and blue light were linearly polarized, the polarization planes of red and blue light were parallel, and the polarization planes of green light were orthogonal to them. It was recognized that

Comparative Example 1
A projection system of Comparative Example 1 was produced in the same manner as in Example 1 except that the projected image display member 4 was used instead of the projected image display member 1.
Comparative Example 2
A projection system of Comparative Example 2 was produced in the same manner as Example 3 except that the projection image display member 5 was used instead of the projection image display member 3.
Comparative Example 3
A front info display CY-DF100D made by Panasonic was prepared as a projection device. When the polarization state of this projection light was confirmed using a bandpass filter and an absorption type linear polarization plate, it was confirmed that red light, green light, and blue light were all linearly polarized, and the polarization planes of each color were all parallel. It was. A λ / 4 wavelength phase difference plate was installed at the light exit of the projector in the same manner as in Example 1. A projection system of Comparative Example 3 was produced in which this projection light was reflected by the projection image display member 1 to view a virtual image.

Comparative Example 4
A BenQ DLP projector MX503 was prepared as a projection device. When the polarization state of the projection light was confirmed using a bandpass filter and an absorption linear polarization plate, it was confirmed that all of red light, green light, and blue light were non-polarized light. In the same manner as in Example 3, a λ / 4 wavelength phase difference plate was installed at the tip of the projector lens. A projection system of Comparative Example 4 shown in FIG. 2 was produced in which the image of the projector was projected onto the projection image display member 3 and the real image was seen.

Measurement method In the dark room, the images of each projector were projected with uniform white display, and the brightness and color were evaluated. For the evaluation of brightness, for Examples 1 and 2 of the virtual image projection and Comparative Examples 1 and 3, the reflectance ratio with respect to the aluminum vapor deposition mirror was measured and evaluated according to the following criteria.
A: 0.8 or more B: 0.6 to less than 0.8 C: less than 0.6 In addition, for Examples 3 and 4 of the screen projection and Comparative Examples 2 and 4, the luminance ratio with respect to the white copy paper was measured. The evaluation was based on the following criteria.
A: 2.0 or more B: 1.5 to less than 2.0 C: less than 1.5 The color was evaluated visually according to the following criteria.
A: Recognizable as white as a whole B: Mostly recognized as white (allowable)
C: The result in which coloring is clearly recognized is shown in Table 4.

DESCRIPTION OF SYMBOLS 1 Projector 2 (lambda) / 4 wavelength phase difference plate 3 Rear pro screen 4 Projection image display member

Claims (4)

A layer in which a cholesteric liquid crystal phase having a central wavelength of selective reflection is fixed at 750 to 620 nm, a layer in which a cholesteric liquid crystal phase having a central wavelength of selective reflection is fixed in 630 to 500 nm, and a central wavelength of selective reflection in 530 to 420 nm Including a layer with a fixed cholesteric liquid crystal phase,
The central wavelengths of the selective reflection of the three layers are different from each other by 50 nm or more, and the twist direction of the spiral of the cholesteric liquid crystal between the layer in which the cholesteric liquid crystal phase having the central wavelength of selective reflection at 630 to 500 nm is fixed and the other two layers is Vice versa
The haze value at a wavelength of 550 nm measured from either surface is less than 2.0,
Projection image display member used as a half mirror for projection image display.   The projection image display member according to claim 1, which is used as a combiner for a head-up display.   A projection system comprising: a projector that projects linearly polarized light; a wave plate that converts the linearly polarized light into circularly polarized light; and the projection image display member according to claim 1.   The projection system according to claim 9, wherein the wavelength plate that converts the linearly polarized light into circularly polarized light is a λ / 4 wavelength phase difference plate.

Images