JP2015141318A - projection system and projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a projection system that can render a projection image sharp even in a bright location and less in a failure such as color unevenness and the like, and to provide a projector that suppresses a failure in a projection image such as color unevenness and the like in display of the projection image by a projection image display member including a layer having a cholesteric liquid crystal phase immobilized.SOLUTION: There is provided a projection system including a projector which includes a drawing device for emitting polarized light and a projection image display member for displaying a projection image projected from the projector. An intermediate image screen is included between the drawing device and the projection image display member, and a phase difference film that has a phase difference large enough for putting the polarized light into pseudo non-polarized light is included between the drawing device and the intermediate image screen. The projection image display member includes a layer having a cholesteric liquid crystal phase immobilized. There is also provided a projector including the drawing device, the intermediate image screen, and the phase difference film.

Description

  The present invention relates to a projection system and a projector. More specifically, the present invention relates to a projection system including a projector and a projection image display member including a layer in which the cholesteric liquid crystal phase is fixed, and display of a projection image on the projection image display member including a layer in which the cholesteric liquid crystal phase is fixed. Relating to projectors.

In recent years, the usage scenes of projectors are expanding for home theater use and in-vehicle use. In many projectors currently used due to the light source and drawing method of the projector, the projection light is polarized.
In Patent Document 1, a reflective film including a layer in which a cholesteric liquid crystal phase that reflects right-circularly polarized light or left-circularly polarized visible light is fixed on a screen is used, and polarized projection light from a projector is received in an environment with external light. A system that selectively reflects and makes the projected image clearer has been proposed.
In Patent Document 2, the color unevenness of the display image on the screen of the Fresnel lens generated when the polarization state of the polarized projection light is disturbed by the lens or mirror in the projection lens, and the polarization state of the light is pseudo-polarized. It has been proposed to solve this problem by using a polarization conversion member.

JP-A-5-107660 JP 2005-321544 A

  An object of the present invention is to provide a projection system capable of providing a projected image that is clear even in a bright place and has few defects such as color unevenness. Another object of the present invention is to provide a projector in which a projected image is less likely to be defective in color unevenness in displaying a projected image on a projected image display member including a layer in which a cholesteric liquid crystal phase is fixed.

  In the course of research using a reflection film including a layer in which a cholesteric liquid crystal phase is fixed as a projection image display member, the present inventors faced a problem that light and shade and color unevenness occur in a projection image using a commercially available projector. It was discovered that the degree of light and darkness and color unevenness seemed to depend on the wavelength of the projector projection light, the polarization state, and the direction of the polarization plane. This finding was unexpected because the layer with the fixed cholesteric liquid crystal phase reflects either right or left sense circularly polarized light for S-polarized light and P-polarized light as well. Based on this finding, the present inventors have found that the above problem is that the polarized projection light is selected in the cholesteric layer by interference between the reflected light on the outermost surface of the reflective film and the selective reflected light on the cholesteric liquid crystal layer. Assuming that unevenness due to the strengthening or weakening of the reflection is caused by the polarization dependence of the reflectance, further studies were made based on this assumption, and the present invention was completed.

That is, the present invention provides the following [1] to [12].
[1] A projection system including a projector including a drawing device that emits polarized light, and a projection image display member that displays a projection image projected from the projector, wherein the drawing device and the projection image display member A projection image display member including an intermediate image screen and a retardation film having a phase difference of a magnitude that makes the polarized light pseudo-non-polarized between the drawing device and the intermediate image screen. Projection system that includes a layer with a fixed cholesteric liquid crystal phase.
[2] The projection system according to [1], wherein the intermediate image screen includes plastic.

[3] A field lens is provided between the intermediate image screen and the projection image display member, and the field lens changes the direction of light incident from the intermediate image screen side and projects the projection onto the projection image display member. The projection system according to [1] or [2], which adjusts a size of an image.
[4] The projection system according to any one of [1] to [3], in which the drawing device includes a laser light source and the retardation of the retardation film is 200,000 nm or more.
[5] The projection system according to [4], wherein the drawing device is a scanning drawing device using MEMS.
[6] The projection system according to any one of [1] to [5], wherein the retardation film includes a stretched polyethylene terephthalate film.

[7] The projection system according to any one of [1] to [6], wherein the projection image display member includes two or more layers in which a cholesteric liquid crystal phase is fixed.
[8] The projection system according to any one of [1] to [7], wherein the projection image display member is a reflection screen that displays a projection image as a real image on a surface.
[9] The projection system according to any one of [1] to [7], wherein the projection image display member is a half mirror having visible light permeability.
[10] The projection system according to [9], which is a head-up display.
[11] A projector for projecting a projected image onto a projected image display member including a layer in which a cholesteric liquid crystal phase is fixed, and includes a drawing device that emits polarized light, a retardation film, and an intermediate image screen in this order. The retardation film is a projector having a phase difference of a magnitude that makes the polarized light pseudo-non-polarized.
[12] The projector according to [11], wherein the drawing device includes a laser light source, and the retardation of the retardation film is 200,000 nm or more.

  According to the present invention, a projection system capable of providing a projection image which is clear even in a bright place and has few defects such as color unevenness, and a projection image on a projection image display member including a layer in which a cholesteric liquid crystal phase is fixed is displayed. In addition, a projector in which defects such as color unevenness are unlikely to occur is provided.

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.
In this specification, “retardation” or “retardation” represents in-plane retardation. The phase difference can be measured by using a polarization phase difference analyzer AxoScan manufactured by AXOMETRICS and narrowing the measurement wavelength interval in the spectrum scan mode for samples having a phase difference of up to several thousand nm. For samples with a phase difference greater than several thousand nm, the number of stripes from the optical axis to the normal incidence direction is measured by conoscopic observation of a polarizing microscope through a 550 nm bandpass filter to determine the order of interference n. Thus, the phase difference can be calculated by adding nx 550 to the zeroth-order retardation value measured using AxoScan.

In this specification, the measurement wavelength is 550 nm unless otherwise specified. For example, when the phase difference is simply described, the wavelength indicates the phase difference at 550 nm.
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, the “projection system” means a combination of a projector and a projection image display member. The projector and the projection image display member may be separated or integrated.
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 a drawn image may be referred to as an “intermediate image screen” separately from the projected image display member. For example, the projector only has to project an image drawn on a small intermediate image screen on the projection display member.
In this specification, the “projected image display member” means a member for displaying a projected image. The projected image display member is a half mirror that displays the projected image as a virtual image that appears above the projected image display member when viewed by the observer, even if it is a screen that displays the projected image on the surface as a real image. May be.
The projected image may be a single color image, a multicolor image of two or more colors, or a full color image.

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 light bulbs, mercury lamps, fluorescent lamps, and LEDs emit almost natural light, but the characteristic of creating polarized light such as a measurement object such as a filter mounted on these light sources is, for example, manufactured by AXOMETRICS It can be measured using a polarization phase difference analyzer AxoScan or the like.
Moreover, it can measure even if a measuring object is attached 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.

<Drawing device>
The projector includes a drawing device. The drawing device draws an image or a projected image using light from a light source. In this specification, the drawing device is a light source,
It means a device including a light modulator, a laser brightness modulation means, a light deflection means for drawing, and the like.
(light source)
A light source is not specifically limited, A laser light source, LED, a discharge tube etc. can be used. Among these, the laser light source can efficiently use the light emitted with excellent directivity, so that the energy use efficiency is high, and therefore the heat dissipation mechanism can be relatively small, which can contribute to the miniaturization of the projector. Therefore, it is preferable. The laser light source is not particularly limited, and a commercially available semiconductor laser that can irradiate light of a desired wavelength can be selected and used as appropriate.

(Drawing method)
Examples of the drawing method include a two-dimensional spatial light modulator method, a scanning method, and a laser fluorescence excitation method, and can be selected according to the light source to be used and the application.

In the two-dimensional spatial light modulator method, light of each color is modulated and combined by an optical modulator, and an image is formed by a projection lens. Examples of the two-dimensional spatial light modulator include an LCD method using liquid crystal and an LCOS (Liquid Crystal on Silicon) method.
The scanning method is a method in which a light beam is scanned on a screen and an image is contrasted using an afterimage of an eye. For example, the descriptions in JP-A-7-270711 and JP-A-2013-228664 can be referred to. The scanning method is preferable as a drawing method when light having high directivity such as laser light is used. In a scanning method using a laser light source, laser light of each color (for example, red light, green light, and blue light) whose luminance is modulated is bundled into one light beam by a multiplexing optical system or a condensing lens. What is necessary is just to be scanned and drawn by the light deflection means. In the scanning method, the luminance modulation of laser light of each color (for example, red light, green light, and blue light) may be performed directly as a change in intensity of the light source, or may be performed by an external modulator. Examples of the light deflection means include a galvanometer mirror, a combination of a galvanometer mirror and a polygon mirror, or MEMS (microelectromechanical system). Among these, MEMS is preferable. Examples of the scanning method include a random scan method and a raster scan method, but it is preferable to use a raster scan method. In the raster scan method, the laser beam can be driven by a resonance frequency in the horizontal direction and a sawtooth wave in the vertical direction, for example.
Since the scanning system does not require a projection lens, the apparatus can be easily miniaturized, which is preferable.

(Polarization)
In the projection system of the present invention, the light emitted from the drawing device includes at least polarized light (linearly polarized light). In a drawing device or drawing method using a laser light source, the output light of a drawing device using an LCD and LCOS is polarized. When the light emitted from the drawing device includes light having a plurality of wavelengths (colors), it is preferable that the polarization directions (transmission axis directions) of the plurality of light beams are the same or orthogonal to each other.

<Intermediate image screen>
The projection system of the present invention includes an intermediate image screen. An image is drawn on the intermediate image screen. The intermediate image screen is disposed between the drawing device and the projection image display member. The intermediate image screen may be a constituent member of the projector, and may be disposed independently between the projector and the projection image display member, but is preferably a constituent member of the projector.

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.

<Field lens>
A field lens may be disposed between the intermediate image screen and the projection image display member. The field lens is preferably located in close proximity to the intermediate image screen and may be physically adjacent. The field lens has a function of adjusting the size of the projected image on the projected image display member by changing the direction of light incident from the intermediate image screen side. The field lens may disturb the polarization plane of incident polarized light and the light intensity in the same manner as the intermediate image screen.

<Phase difference film>
The projection system of the present invention includes a retardation film having a phase difference of a magnitude that makes the polarized light pseudo-non-polarized between the drawing device and the intermediate image screen.
The phase difference that can make the polarized light non-polarized is described in paragraphs [0022] to [0033] of JP-A-2005-321544. It can be said that it can be non-polarized light. The specific numerical value of the phase difference can be determined according to the drawing device used, the light source, the accuracy required for the projected image, and the like. Typically, the phase difference of the retardation film may be 20000 nm or more. Particularly, in the projection system of the present invention, when a laser light source is used for the drawing device, the retardation of the retardation film should be 200000 nm or more. Is preferable, and it is more preferable to set it as 300000 nm or more. Moreover, in the projection system of this invention, when using a LED light source for a drawing device, it is preferable that the phase difference of a phase difference film shall be 20000 nm or more, and it is more preferable to set it as 30000 nm or more.

  The retardation film is disposed between the drawing device and the intermediate image screen. Intermediate image screens and / or field lenses have birefringence and disturb the polarization state or polarization direction of light from the drawing device. Therefore, it is considered that the polarization dependency of the reflectance is visualized and the above-described color unevenness is generated. Color retardation can be reduced by placing a retardation film between the drawing device and the intermediate image screen so that it is not polarized before entering the intermediate image screen and the field lens. .

The retardation film is preferably disposed so that the optical axis (slow axis) direction is 45 degrees with respect to the polarization direction (polarization transmission axis direction) of the polarized light from the drawing device.
Examples of the retardation film include birefringent materials such as plastic films and quartz plates. Examples of the plastic film include polyester films such as polyethylene terephthalate (PET), polycarbonate films, polyacetal films, and polyarylate films. JP, 2013-257579, A public relations etc. can be referred to for a phase contrast film which has a high phase contrast which has PET as a main ingredient. Commercial products such as optical Cosmo Shine (registered trademark) super birefringence type (Toyobo) may be used.

  In general, plastic films with high phase difference are melt-extruded from resin, cast on drums, etc., and formed into a film shape. It can be formed by stretching at a magnification. In order to promote crystallization and increase the strength of the film, a heat treatment called “heat setting” may be performed at a temperature exceeding the stretching temperature after stretching.

<Configuration of projector>
The projector may include a housing, and the drawing device only needs to be installed inside the housing. The housing is preferably formed of a light shielding material. In the case where the intermediate image screen constitutes a part of the projector, it is also preferable that the intermediate image screen is disposed at the opening of the housing and at the exit of the projection light. The light emitted from the drawing device may be bent by a reflection mirror disposed inside as necessary according to the structure of the housing, and irradiated to the intermediate image screen. When the projector includes a reflection mirror, the retardation film may be disposed between the drawing device and the reflection mirror, or may be disposed between the reflection mirror and the intermediate image screen. Between the two.

<Projection image display member>
The projection image display member used in the projection system of the present invention includes at least one layer 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.
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, or may have a curved surface. It may have a concave shape or a convex shape as a whole.

When the projection image display member is a screen that displays a projection image on the surface as a real image, it 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.
In order to form a real image on the screen, the screen needs to be scattered and reflected with respect to the projection light wavelength. This scattering reflection performance is imparted by a method of forming a diffusion layer formed by mixing fine particles with a binder and applying the mixture on a transparent medium on the light incident side of the screen, or a method of disturbing the uniformity of alignment of the cholesteric liquid crystal layer. be able to. 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, the haze value of the projection image display member in the above case is preferably 2 to 50%, and more preferably 4 to 25%. In this specification, the haze value is {(scattering reflectance of natural light) / (scattering reflectance of natural light + regular reflectance of natural light) × 100 (%)}. The regular reflectance is a spectrophotometer, and the all-angle measurement value of the reflectance can be measured by combining an integrating sphere unit with the spectrophotometer. For the convenience of measurement, the regular reflectance may be a measured value at an incident angle of 5 °, for example. 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.

  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 (light transmittance 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. In this case, the haze value of the projection image display member is preferably 2% or less, and more preferably 1% or less.

(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 region). . 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 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 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 crystalline compound in the 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 selective reflection center wavelength is 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 (when used as a projection image display member). means. 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.

  In the projection system of the present invention, in order to display a full-color projection image, the projection image display member has an apparent selective reflection center wavelength for red light, green light, and blue light, respectively. Just do it. Specifically, the projection image display member may have three selective reflection center wavelengths 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. preferable. Such a property can be achieved by a configuration including three or more cholesteric liquid crystal layers. 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 is a cholesteric liquid crystal layer that selectively reflects either right circularly polarized light or left circularly polarized light with respect to red light (a cholesteric liquid crystal layer having a central wavelength of selective reflection at 750 to 620 nm). ), A cholesteric liquid crystal layer (cholesteric liquid crystal layer having a central wavelength of selective reflection at 630-500 nm) that selectively reflects either right circularly polarized light or left circularly polarized light with respect to green light, and right with respect to blue light 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 circularly polarized light or left circularly polarized light.

  Efficient use of light by adjusting the center wavelength of selective reflection of the cholesteric liquid crystal layer to be used according to the wavelength range of the projection light from the projector used in the projection system of the present invention and the usage mode of the projection image display member A clear projected image can be displayed. In particular, by adjusting the central wavelengths of selective reflection of a plurality of cholesteric liquid crystal layers in accordance with the wavelength range of the projection light from the projector, it is possible to display a clear color projection image with high 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.

  The spiral senses of the cholesteric liquid crystal layers having different selective reflection center wavelengths may all be the same or different.

  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.

(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 the rod-shaped nematic liquid crystal compound include azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, and 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. 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 3% by mass or more, the effect of improving the crosslinking density is higher, and when it is 20% by mass or less, the stability of the cholesteric liquid crystal layer is higher.

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 alignment 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. A cholesteric liquid crystal layer in which the cholesteric regularity is fixed by coating the cholesteric liquid crystal layer on the coated cholesteric liquid crystal layer and drying it to obtain a coating film, and irradiating the coating film with an actinic ray to polymerize the cholesteric liquid crystalline 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 the light irradiation. The irradiation energy is preferably ^{0.02J / cm 2 ~50J / cm 2} , 0.1J / cm 2 ~1.5J / 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.

(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, 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 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.
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 in the case where the projection image display member is a half mirror, it is the surface of the base material described later, You may provide in the surface on the opposite side to the surface in which the cholesteric liquid crystal layer was provided.

  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. For example, JP-A-8-122504 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.
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 the base material include acrylic resins (acrylic esters such as polymethyl (meth) acrylate), polycarbonate, cyclic polyolefins such as cyclopentadiene polyolefin and norbornene polyolefin, polyolefins such as polypropylene, polystyrene, etc. And aromatic vinyl polymers, 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, the material is preferably an acrylate, urethane acrylate, epoxy acrylate, or the like. .
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 member, it is preferable that the projection image display member be provided with a uniform thickness.

<Projection system>
The projection system of the present invention may be a large system used in a movie theater or the like, may be a home theater system, or may be a so-called nano projector system, and its use is not particularly limited. . By using a half-mirror structure having visible light transmission as a projection image display member and using it as a combiner, the projection system of the present invention can be used for a head-up display or a head-mounted display. By using a laser as the light source and adopting a scanning type for the drawing system, it is possible to design a smaller projection system.

  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.

Example 1
Production of retardation film:
By directly reacting terephthalic acid and ethylene glycol at a mass ratio of 4.7: 1.8, distilling off water, esterifying, and then using a direct esterification method in which polycondensation is performed under reduced pressure, a continuous polymerization apparatus is used. Raw material polyester 1 (Sb catalyst system PET) was obtained. This raw material polyester 1 was put into a hopper of a single screw kneading extruder. The raw material polyester 1 was melted at 300 ° C., extruded from a die onto a cooling cast drum set at a temperature of 25 ° C., and adhered to the cooling cast drum using an electrostatic application method. It peeled using the peeling roll arrange | positioned facing the cooling cast drum, and obtained the unstretched polyester film 1 of thickness 4mm.
Subsequently, the unstretched polyester film 1 was guided to a tenter (lateral stretching machine), and heated by hot air of 90 ° C. blown from a hot air nozzle while holding both ends of the film with clips.

  This heated unstretched polyester film 1 was transversely stretched in the TD direction using a tenter at a stretch ratio of 4.3 times in the width direction. Next, the film surface temperature of the polyester film was controlled at 180 ° C. and held for 15 seconds to perform heat setting. Thereafter, the polyester film was cooled at a cooling temperature of 50 ° C. to obtain a PET film 1 having a thickness of 950 μm and a retardation of 100,000 nm.

  A field lens of a Pioneer LD projector (product name AVIC-ZH10009HUD AR HUD unit) having a scanning type drawing device including a laser light source and MEMS and two microlens arrays located on the light source side were removed. Subsequently, the above-prepared retardation 100000 nm PET film 1 is laminated with its slow axis parallel to each other, and its slow axis is oriented at 45 degrees with respect to the polarization direction of the laser light of the light source. The microlens array was cut out and attached to the side of the light source. The microlens and the field lens were again incorporated into the LD projector main body, and a projector of Example 1 having a retardation film with a total retardation of 400000 on the light source side surface of two microlenses was produced.

Example 2
A retardation film having a total retardation of 300,000 was prepared using three PET films 1 having a retardation of 100,000 nm, and this film was used in the same manner as in Example 1 except that this film was used instead of the retardation film having a retardation of 400,000. Thus, the projector of Example 2 was produced.

Example 3
A retardation film having a total retardation of 200,000 was prepared using two PET films 1 having a retardation of 100,000 nm, and this film was used in the same manner as in Example 1 except that this film was used in place of the retardation film having a retardation of 400,000. Thus, the projector of Example 3 was produced.

Comparative Example 1
The evaluation described below was performed using the projector used in Example 1 with no four PET films 1 attached.
Comparative Example 2
A projector of Comparative Example 2 was formed in the same manner as Example 1 except that four sheets of PET film 1 were attached to the outside of the field lens (opposite the drawing device side).
Comparative Example 3
A projector of Comparative Example 3 was formed in the same manner as Example 1 except that one PET film 1 was used instead of the four PET films 1.

Preparation of half mirror Using a wire bar at room temperature so that the dry film thickness after drying coating liquid A-1 shown in Table 1 is 3 μm on the rubbing treated surface of Fujifilm PET subjected to rubbing treatment. 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 70 ° C. for 6 to 12 seconds at an output of 60% with a fusion D bulb (lamp 90 mW / cm). A liquid crystal layer was obtained. On this liquid crystal layer, coating liquid A-2 shown in Table 1 was applied at room temperature so that the thickness of the dried film after drying was 3.5 μm, and then dried, heated, and irradiated with UV in the same manner as described above. A second liquid crystal layer was formed. Further, the coating liquid A-3 shown in Table 1 is applied on the second liquid crystal layer at room temperature so that the thickness of the dried film after drying is 4 μm, and then drying, heating, and UV irradiation are performed in the same manner as described above. Then, a third liquid crystal layer was formed to obtain a laminate having central wavelengths of selective reflection at 450 nm, 530 nm, and 640 nm.
On one side of an acrylic plate (Mitsubishi Rayon Co., Ltd.) having a thickness of 10 mm, 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 cholesteric liquid crystal layer side surface of the laminate produced above were bonded together so as not to contain bubbles, and then heated at 30 ° C. with a fusion D bulb (lamp 90 mW / cm) at an output of 60% and 6 to 6%. A half mirror was formed by UV irradiation for 12 seconds.

Evaluation was performed according to the following method.
In the dark place, the projector projection image was kept in a white display state, and the projection image reflected by the half mirror including the cholesteric liquid crystal layer produced above was visually observed. At this time, visual observation was performed with the cholesteric liquid crystal layer surface on the incident light side, and the results obtained according to the following evaluation criteria are shown in Table 3.
A: Both color and brightness are uniform.
B; Slight color unevenness is observed. (Acceptable)
C: Clear color unevenness is observed.

Claims (12)

A projection system including a projector including a drawing device that emits polarized light and a projection image display member that displays a projection image projected from the projector,
Including an intermediate image screen between the drawing device and the projected image display member;
Between the drawing device and the intermediate image screen, including a retardation film having a phase difference of a magnitude that makes the polarized light pseudo-polarized,
A projection system, wherein the projection image display member includes a layer in which a cholesteric liquid crystal phase is fixed. The projection system of claim 1, wherein the intermediate image screen comprises plastic. A field lens is provided between the intermediate image screen and the projection image display member, and the field lens changes the direction of light incident from the intermediate image screen side to increase the size of the projection image on the projection image display member. The projection system according to claim 1, wherein the projection is adjusted. The projection system according to any one of claims 1 to 3, wherein the drawing device includes a laser light source, and the retardation of the retardation film is 200,000 nm or more. The projection system according to claim 4, wherein the drawing device is a scanning drawing device using MEMS. The projection system according to claim 1, wherein the retardation film includes a stretched polyethylene terephthalate film. The projection system according to claim 1, wherein the projection image display member includes two or more layers in which a cholesteric liquid crystal phase is fixed. The projection system according to claim 1, wherein the projection image display member is a reflection screen that displays a projection image as a real image on a surface. The projection system according to any one of claims 1 to 7, wherein the projection image display member is a half mirror having visible light permeability. The projection system according to claim 9, wherein the projection system is a head-up display. A projector for projecting a projected image onto a projected image display member including a layer in which a cholesteric liquid crystal phase is fixed,
A drawing device that emits polarized light, a retardation film, and an intermediate image screen in this order,
The retardation film is a projector having a phase difference of a magnitude that makes the polarized light pseudo-non-polarized. The projector according to claim 11, wherein the drawing device includes a laser light source, and a retardation of the retardation film is 200,000 nm or more.